船舶与海洋工程静力学》课程考试 模 拟 试 卷A

第一篇：船舶与海洋工程静力学》课程考试 模 拟 试 卷A

机

密★启用前

大连理工大学网络教育学院

2015年3月份《船舶与海洋工程静力学》课程考试

模 拟 试 卷

考试形式：闭卷 试卷类型：（A）

☆ 注意事项：本考卷满分共：100分；考试时间：90分钟。

学习中心______________ 姓名____________ 学号____________

一、单项选择题（本大题共5小题，每小题2分，共10分）

1、（）的储备浮力往往在100%以上。

A．内河驳船

B．海船

C．货船

D．军舰

2、某船的首吃水dF=6.3m，尾吃水dA=5.5m，船的设计吃水为6.0 m，则该船的平均吃水为（）。A．6.3m

B．6.0m

C．5.9m

D．5.5m

3、每厘米吃水吨数TPC

3333AW100，这里AW指的是（）。

A．水线面面积

B．横剖面面积 C．方形系数

D．棱形系数

4、右图为船舶小角度倾斜示意图，指出船舶的横稳心半径？（）A．g1gB．B1B2 C．BO D．BM

5、对稳性衡准数K值的要求为？A．K

1B．K0

C．K1

D．K1

（）

二、多项选择题（本大题共5小题，每小题4分，共20分）

1、常采用的固定在船体上的直角坐标系，哪个是正确的？（）

大工《船舶与海洋工程静力学》课程考试 模拟试卷（A）第1页

共4页 A．基平面、中站面和中线面的交点为原点

B．基线面与中线面的交线是x轴 C．y轴指向左舷为正

D．z轴向上为正

2、对于船型系数，说法正确的是？（）

A．船型系数是无因次系数

B．船型系数一般都大于1 C．方形系数表示水线面的肥瘦程度

D．棱形系数表示排水体积沿船长方向的分布情况

3、关于中和平面，说法正确的有哪些？（）A．中和平面的高度为dd2dGM B．中和平面的高度为d2+GM

C．小量载荷p加载在中和平面的上方, 增加初稳心高 D．小量载荷p加载在中和平面的下方, 增加初稳心高

4、对于船舶横倾状态，下列说法正确的是?（）

A．正浮时候有横倾角 B．正浮时候没有横倾角

C．平均吃水等于艏吃水与艉吃水和的一半

D．平均吃水等于艏吃水减去艉吃水

5、下列措施可增加船舶稳性的有哪些？（）

A．采用较大的舷弧

B．重在舷侧加装一个凸出体 C．船两舷水线附近加装浮箱 D．水线以上的横剖线适当“外飘”

三、判断题（本大题共5小题，每小题2分，共10分）

1、应用辛式一法时候，长度L的等分数目n没有任何限制。（）

2、船舶设计水线长一般大于船舶总长。（）

3、船体型线图可表示船舶的结构组成。（）

4、自由液面的存在会降低船舶的稳性。（）

5、倾斜试验的目的是确定船舶的重量和重心位置。（）

四、简答题（本大题共5小题，每小题6分，共30分）

1、什么是船舶抗沉性？ 什么是船舶的浮性？

大工《船舶与海洋工程静力学》课程考试 模拟试卷（A）第2页

共4页

2、请给出船舶的首垂线和尾垂线的定义。

3、普通货船所需计算的典型装载情况有哪些？通常所说的设计排水量指的是哪种状态下的排水量?

4、请叙述在静力学计算中是怎样选取坐标系统的？

5、船舶的初稳心高越大越好，对吗？为什么？

五、计算题（本大题共3小题，每小题10分，共30分）

1、证明每度横倾力矩M0

大工《船舶与海洋工程静力学》课程考试 模拟试卷（A）第3页

共4页 GM。并求出横倾力矩MH作用于船上引起的横倾角度H。57.32、某海洋客船船长L=130m，船宽B=15m，吃水d=6m，排水体积▽=6468m3，中横剖面面积AM=81m2，求：

（1）方形系数CB；（2）中横剖面系数CM；（3）棱形系数Cp。

3、某船主要数据为：船长L=135m，船宽B=14.2m，首吃水dF=4.8m，尾吃水dA=5.2m，排水量△=5200t，横稳性高GM=0.95m，每厘米吃水吨数TPC=13.8t/cm，漂心纵向坐标XF=3.5m，试求：在x=3.5m，y=1.0m，z=9.0m处装载200t货物后船舶的浮态和初稳性。（装卸载荷后新的初稳性高的公式如下：G1MGM+pd）dzGMp2大工《船舶与海洋工程静力学》课程考试 模拟试卷（A）第4页

共4页

第二篇：船舶与海洋工程

基本介绍

随国际形式的复杂化、国际交往与运输的频繁以及国内陆路交通的形势严峻，船舶与海洋工程成为捍卫疆域完整以及扩大交往密度而亟待发展的学科。该专业运用物理、数学、力学、船舶与海洋工程原理的基本理论和基本知识，掌握船舶与海洋结构物的设计方法，研究船舶轮机的工作原理；具有船体制图，应用计算机进行科研的初步能力；熟悉船舶与海洋结构物的建造法规和国内外重要船级社的规范，了解造船和海洋开发的理论前沿，新型舰船和海洋结构物的应用前景和发展动态；船舶与海洋结构物设计制造学主要从事新型船舶与海洋工程结构物，水下深潜器的设计开发，主要研究领域有：船舶与海洋工程和其它各种结构的强度、刚度、疲劳断裂、振动及结构可靠性；海洋流体力学；船舶阻力、推进、操纵性和耐波性。中国部分研究成果已达到国际水平。轮机工程主要是研究船舶机械的原理以及应用，随信息技术的不断发展，雷达、遥感技术的应用，环境保护要求的提高以及对能源的更高效利用，船舶的动力装置、船舶电器设备、轮机自动化系统等都面临着新的技术要求与挑战。个别院校在轮机工程专业里还设置了分支学科——轮机管理专业，以培训能够从事海洋船舶轮机运行管理工作，具有船舶动力装置系统国

航、维修、保养及研究。水声工程主要研究潜艇等船舶处于水下的船舶在水中的探测、定位以及对水中兵器的引导和对抗。中国正积极进行声纳在水中传输特性的研究，并在该领域取得一定的成功。

学科优势

造船与海洋工程工业是一项周期长、资金密集、科技密集、劳动密集型传统产业，对中国的综合国力发展有至关重

要的影响。随着国际形势的复杂化、国际交往运输的频繁化，船舶与海洋工程成为了捍卫疆域完整以及扩大交往密度而亟待发展的学科，它是为水上交通运输、海洋资源开发和海军部队提供各类装备和进行海洋工程设计、建造的工程技术领域。虽然中国的船舶工业通过近几年的发展取得了较大的成绩，但与世界发达国家如日本、韩国等相比，仍然有很大的距离。为了缩短船舶工业发展的差距，中央主要领导吴邦国、温家宝等对大力发展中国船舶工业做出

了重要批示，确立了中国在2015年将努力建设成为世界第一造船大国的战略目标。根据此目标，到2015年，中国造船占到国际船舶的份额将达到35%。

在这种背景下，中国船舶工业面临着前所未有的发展契机，也使拥有船舶与海洋工程专业的高校面临着巨大的挑战和千载难逢的机遇。如何适应新的形势，培养出一批德、智、体、美全面发展的具备现代船舶与海洋工程设计、建造、研究的基本理论和基础知识，并且基础扎实、专业知识面广、动手能力强、具有创新精神和实践能力的应用型、复合型人才，这是船舶与海洋工程专业目前必须面对和要解决的重要问题。

学习形势

船舶与海洋工程专业是培养从事船舶、水下运载器及各类海洋结构设计、研究、生产制造、检验及海洋开发技术经济分析的高级工程技术人才的学科。这个专业的学生主要学习物理、数学、力学、船舶及海洋工程

原理的基本理论和基本知识；掌握船舶与海洋结构物的设计方法；具有船体制图，应用计算机进行科研的初步能力；熟悉船舶与海洋结构物的建造法规和国内外重要船级社的规范；了解造船和海洋开发的理论前沿，新型舰船和海洋结构物的应用前景和发展动态；掌握文献检索、资料查询的基本方法。其基础课包括自然辨证法、科学社会主义理论、外语、高等工程数学、计算机图形处理及软件工程基础、企业管理等；技术基础课包括海洋结构物原理及设计、船舶原理与设计、船舶与海洋结构物强度、流体力学、海洋防腐技术、船舶与海洋结构物在波浪中的运动理论、决策理论与方法、结构可靠性原理；专业课包括工程技术经济论证方法、企业信息管理、船舶科学与工程进展、海洋系统工程、海洋工程水池试验技术、结构优化设计、船舶与海洋结构物现代建造方法、浮式系统等。

大学四年后学生须掌握船舶与海洋工程领域的坚实基础理论和宽广的专业知识，以及解决工程问题的现代化实验研究方法和技术手段，并且具有独立从事新产品开发设计能力、生产工艺设计及实施能力、工程管理的能力。

业务培养要求

本专业学生主要学习物理、数学、力学、船舶及海洋工程原理的基本理论和基本知识；掌握船舶与海洋结构物的设计方法；具有船体制图，应用计算机 进行科研的初步能力；熟悉船舶与海洋结构物的建造法规和国内外重要船级社的规范；了解造船和海洋开发的理论前沿，新型舰船和海洋结构物的应用前景和发展动态；掌握文献检索、资料查询的基本方法，具有一定的科学研究和实际工作能力。

主干学科

数学、力学、船舶与海洋工程

主要课程

理论力学、材料力学、流体力学、结构力学、船舶原理（静力学、船舶阻力、船舶推进、船舶操纵等）、船体制图、船舶材料与焊接、船舶英语、船舶结构与强度、船体振动

等

主要实践性教学环节

包括金工实习(3周)、船厂实习(3周)、上舰实习(2 周)等，一般总共安排8周。

主要专业实验

船模阻力实验、螺旋桨试验、船模自航试验及结构实验应力分析等

修业年限

四年

授予学位

工学学士

相近专业

轮机工程

毕业生应获得以下几方面的知识和能力

1．掌握船舶动力装置、电器、液压、气动和机电一体化等方面的基础知识；

2．掌握轮机工况检测、轮机系统的保养和维修等基本技术；

3．具有操纵船舶动力装置，覆行船舶监修、监造职责的初步能力；

4．熟悉有关海船运输安全方面的公约和法律法规；

5．了解海洋运输船舶的发展动态；

6．掌握文献检索、资料查询的基本方法，具有初步的科学研究和实际工作能

力。

开设院校

大连海事大学 武汉理工大学 哈尔滨工业大学 哈尔滨工程大学 天津大学 大连理工大学 上海交通大学 华中科技大学 华南理工大学 河海大学 中国石油大学（华东）上海海事大学 中国海洋大学 厦门集美大学

广东海洋大学 江苏科技大学 重庆交通大学 大连海洋大学 山东交通学院 浙江海洋学院 青岛科技大学

华中科技大学文华学院 青岛远洋船员学院 武汉船舶职业技术学院 渤海船舶职业技术学院

就业趋势

船舶与海洋工程专业学生毕业后可签约到船舶与海洋工程设计研究单位、海事局、国内外船级社、船舶公司、船厂、海洋石油单位、高等院校、船舶运输管理、船舶贸易与经营、海关、海上保险和海事仲裁等部门，从事船舶与海洋结构物设计、研究、制造、检验、使用和管理等工作，也可到相近行业和信息产业有关单位就业。此外，还可争取留学资格到美国、加拿大、英国、挪威、德国、日本等国留学深造。当然，也可以报考相关专业的研究生进一步深造。据各高校有关就业部门统计，船舶与海洋工程专业学生就业形势不错。现在很多学生喜欢选择金融、工商管理、市场营销、信息技术等专业，所以高校中就读传统的船舶与海洋工程专业者已经远不如以前众多，而且该专业人才退休、老化普遍存在。再加上目前开设相关专业的学校已经不多，物以稀为贵，所以船舶与海洋工程这个专业的毕业生出去后容易受到用人单位的欢迎。像重庆交通学院还是西南地区惟一开设船舶与海洋工程专业的高

校。21世纪是海洋经济时代，人类将多方位的开发利用海洋，如海洋资源开发利用、海洋能源开发利用、海洋空间开发利用、海洋交通与通讯通道的开发利用等，本专业将会有广阔的发展前景。

第三篇：船舶与海洋工程

船舶与海洋工程,主要课程:理论力学、材料力学、流体力学、结构力学、船舶与海洋工程原理.专业实验:船模阻力实验、螺旋桨试验、船模自航试验及结构实验应力分析等.学制:4年,授予学位:工学学士,相近专业:轮机工程.就业前景:主要到船舶与海洋结构物设计、研究、制造、检验、使用和管理等部门从事技术和管理方面的工作.首先明确一点,在学科划分上船舶与海洋工程是一级学科,下属有船舶工程/海洋工程、轮机工程、水声工程3个二级学科,这里的排名是中国大学船舶与海洋工程专业排名.上海交通大学

地处国际航运的中心城市的上海,中国船舶工业的老牌大学上交地理优势极为明显,加上上海市对人才的吸引能力,使得交大在近几十年以来一直都稳做船舶院校老大位置.虽然近几年大连理工凭借其临近日韩的优势发展壮大了不少,大工的学生在业内的认可程度也日渐提高,但是想要撼动交大的老大地位恐怕尚需时日.哈尔滨工程大学

虽然继承了“哈军工”大部分家当,但当老一辈的牛人渐渐老去后我们真不知道当年的哈船院在十年以后将会是个什么样子.军品是哈工程的强项,但是学科发展受国家政策影响较大,在市场经济的今天,在别的学校都在拼命做项目赚钱的今天,哈工程的地位无比尴尬.另外,由于北国哈尔滨对人才的吸引力远远不如经济发达的东部沿海城市,所以人才断档问题比较严重,但如今仍然有以两位老院士为代表的老底在,排到第二也属合情合理.武汉理工大学

武汉理工大学的造船专业可以追溯到1946年武昌海事职业技术学校造船科,1952年院系调整时造船系被调整至上海交通大学.1958年重建,1963年交通部院系调整,大连海运学院(现大连海事大学)造船系整体搬迁至武汉,与当时的武汉水运工程学院造船系合并.80年代初至90年代中期,由于长江内河航运繁忙,武汉理工(时为武汉水运工程学院)造船系显赫一时,可以说在民品的设计和研究方面仅次于上交.一批骨干教师在当时国内的造船界极高的声誉.如今的武汉理工大学造船专业虽然不如当年名声那么响亮,但是在内河市场上仍然具有统治力,在高性能船舶方面特色鲜明.虽然地处内陆,但已在华南,华东设有设计研究所.如果学校能够更加开放,管理更加有力的话,相信重现辉煌指日可待.大连理工大学

大连理工大学的造船专业在2000年以后可谓是异军突起.如今良好的发展势头应该说内部是得意于学院的国际化发展战略--学生在本科阶段去日本实习,与日韩的造船高校进行了广泛和深入的合作与交流.外部是得意于地处大连的地理位置和国际造船行业从日韩向中国转移的大趋势.虽然没有交大,哈船那样显赫的历史,但发展势头强劲,假以时日前途无量.华中科技大学

华科的造船系和别的专业相比一直都不怎么起眼,70年代建系以后鲜有什么骄傲的成绩拿出手.现如今该校造船系发展偏结构比较明显,流体这一块继石仲堃以后迟迟没人接班.老师做的项目非船项目比较多,船方面的项目主要跟701所和719所合作.由于学校实力相当强,所以学生仍然比较受欢迎.其实武汉理工和华科向来互相不服,但从师资力量,学校重视程度,试验设施等各方面来看,华科的造船稍逊一筹.天津大学

天津大学的船海系隶属于建筑工程学院,分船舶工程和海洋工程两个方向,也是国内为数不多的搞海洋工程比较有底蕴的院校.但是建筑工程学院更牛的在港航专业,3个院士都是港航的,来招聘的单位也是港航方面的单位.天大的造船不仅在国内造船界很少被提及,在校内也不受重视.排到第六应该也是合情合理的了.江苏科技大学

虽然造船专业是该校的王牌专业,虽然曾经的镇江船院也是国防科工委的院校,但是学校目前仍然是2本(可能江苏省内是一本)至今尚无造船博士点.实力与前面几所学校根本不在一个档次,暂时位居末席.在上述中国大学船舶与海洋工程专业排名中,排名前四的四所学校的船舶与海洋结构物设计制造均为国家级重点学科.船舶工程主要修理建造各类船舶,海洋工程主要主要从事海上采油.就业单位主要有修造船厂(如沪东中华,外高桥等),海上运输公司(如中国远洋),石油公司(如中海油),海事局(需要本科或研究生应届毕业生报考国家直属机构-海事局公务员,限应届毕业),船级社(一般需要有船厂经验外语好的),高校(博士或硕士学历).总体而言,就业基本没大问,工资刚开始两千至三千/月(单位地点,毕业院校,单位制度造成差异),工作两年月工资基本在五千至七千月,且工资出现两极分化(进船级社如ABS,DNV等月收入在万元,很多技术好的都跳去船级社).如果想在这个领域吃香,建议小方向选择海洋工程,学好外语,最好到可以交流地步(进船级社),这两点做到了工作不愁,工资不愁.船舶与海洋工程专业是培养从事船舶、水下运载器及各类海洋结构设计、研究、生产制造、检验及海洋开发技术经济分析的高级工程技术人才的学科。这个专业的学生主要学习物理、数学、力学、船舶及海洋工程原理的基本理论和基本知识；掌握船舶与海洋结构物的设计方法；具有船体制图，应用计算机进行科研的初步能力；熟悉船舶与海洋结构物的建造法规和国内外重要船级社的规范；了解造船和海洋开发的理论前沿，新型舰船和海洋结构物的应用前景和发展动态；掌握文献检索、资料查询的基本方法。其基础课包括自然辨证法、科学社会主义理论、外语、高等工程数学、计算机图形处理及软件工程基础、企业管理等；技术基础课包括海洋结构物原理及设计、船舶原理与设计、船舶与海洋结构物强度、流体力学、海洋防腐技术、船舶与海洋结构物在波浪中的运动理论、决策理论与方法、结构可靠性原理；专业课包括工程技术经济论证方法、企业信息管理、船舶科学与工程进展、海洋系统工程、海洋工程水池试验技术、结构优化设计、船舶与海洋结构物现代建造方法、浮式系统等。

大学四年后学生须掌握船舶与海洋工程领域的坚实基础理论和宽广的专业知识，以及解决工程问题的现代化实验研究方法和技术手段，并且具有独立从事新产品开发设计能力、生产工艺设计及实施能力、工程管理的能力。

就业趋势

船舶与海洋工程专业学生毕业后可签约到船舶与海洋工程设计研究单位、海事局、国内外船级社、船舶公司、海洋石油单位、高等院校、船舶运输管理、船舶贸易与经营、海关、海上保险和海事仲裁等部门，从事船舶与海洋结构物设计、研究、制造、检验、使用和管理等工作，也可到相近行业和信息产业有关单位就业。此外，还可争取留学资格到美国、加拿大、英国、挪威、德国、日本等国留学深造。当然，也可以报考相关专业的研究生进一步深造。据各高校有关就业部门统计，船舶与海洋工程专业学生就业形势不错。现在很多学生喜欢选择金融、工商管理、市场营销、信息技术等专业，所以高校中就读传统的船舶与海洋工程专业者已经远不如以前众多，而且该专业人才退休、老化普遍存在。再加上目前开设相关专业的学校已经不多，物以稀为贵，所以船舶与海洋工程这个专业的毕业生出去后容易受到用人单位的欢迎。像重庆交通学院还是西南地区惟一开设船舶与海洋工程专业的高校。相关链接 学制：四年 授予学位：工学学士 体检要求：色盲与色弱受限。

开设院校：中国石油大学、天津大学、大连理工大学、大连海事大学、大连水产学院、哈尔滨工程大学、上海交通大学、上海海运学院、河海大学、华东船舶工业学院、浙江海洋学院、中国海洋大学、华中科技大学、武汉理工大学、华南理工大学、广东海洋大学、重庆交通学院等

第四篇：船舶与海洋工程专业英语

船舶与海洋工程英语

目录

Part 1.船舶与海洋工程英语

1.The Naval Architect…………………………………………….……….….....1 2.Definitions, Principal Dimensions……………………………….….………....3 3.Merchant ship Types………………………………………………..…………10 4.Ship Design…………………………………………………………………16 5.General Arrangement……………………………………………………....…20 6.Ship Lines……………………………………………………..…………...…25 7.Ship Equilibrium, Stability and Trim………………………………………..28 8.Estimating Power Requirements………………………………………….….33 9.Ship Motions, Maneuverability………………………………………………37 10.The Function of Ship Structural Components……………………………………….....40 11.Structural Design, Ship Stresses…………………………………………………….......43 12.Classification Societies…………………………………………………...…48 13.Shipyard, Organization, Layout…………………………………..….....…..53 14.Planning, From Contract to Working Plans……………………………...….56 15.Lines Plan and Fairing, Fabrication and Assembly………………………....58 16.Launching and Outfitting…………………………………………………....61 17.Sea Trials……………………………………………………………………64 18.Marine Engines………………………………………………………………………...66 19.Marine Electrical Equipment…………………………………………..……71 20.Unattended Machinery Spaces……………………………………….……..76 21.Mobile Drilling Platforms……………………………………………………………...81 22.Examples of Offshore Structures……………………………………….…..85 23.Oceanographic Submersibles…………………………………………….…91 24.Application of Engineering Economics to Ship Design……………..……..94 25.Computer Development and the Naval Architect………………………..…98 Part2.26.船舶英语实用词汇手册……………………………………………………………..101 27.船舶英语缩略语…………………………………………………………………...…129

Lesson One

The Naval Architect A naval architect asked to design a ship may receive his instructions in a form ranging from such simple requirements as ―an oil tanker to carry 100 000 tons deadweight at 15 knots‖ to a fully detailed specification of precisely planned requirements.He is usually required to prepare a design for a vessel that must carry a certain weight of cargo(or number of passengers)at a specified speed with particular reference to trade requirement;high-density cargoes, such as machinery, require little hold capacity, while the reverse is true for low-density cargoes, such as grain.Deadweight is defined as weight of cargo plus fuel and consumable stores, and lightweight as the weight of the hull, including machinery and equipment.The designer must choose dimensions such that the displacement of the vessel is equal to the sum of the dead weight and the lightweight tonnages.The fineness of the hull must be appropriate to the speed.The draft------which is governed by freeboard rules------enables the depth to be determined to a first approximation.After selecting tentative values of length, breadth, depth, draft, and displacement, the designer must achieve a weight balance.He must also select a moment balance because centres of gravity in both longitudinal and vertical directions must provide satisfactory trim and stability.Additionally, he must estimate the shaft horsepower required for the specified speed;this determines the weight of machinery.The strength of the hull must be adequate for the service intended, detailed scantlings(frame dimensions and plate thicknesses)can be obtained from the rules of the classification society.These scantings determine the requisite weight of hull steel.The vessel should possess satisfactory steering characteristics, freedom from troublesome vibration, and should comply with the many varied requirements of international regulations.Possessing an attractive appearance, the ship should have the minimum net register tonnage, the factor on which harbour and other dues are based.(The gross tonnage represents the volume of all closed-in spaces above the inner bottom.The net tonnage is the gross tonnage minus certain deductible spaces that do not produce revenue.Net tonnage can therefore be regarded as a measure of the earning capacity of the ship, hence its use as a basis for harbour and docking charges.)Passenger vessels must satisfy a standard of bulkhead subdivision that will ensure adequate stability under specified conditions if the hull is pierced accidentally or through collision.Compromise plays a considerable part in producing a satisfactory design.A naval architect must be a master of approximations.If the required design closely resembles that of a ship already built for which full information is available, the designer can calculate the effects of differences between this ship and the projected ship.If, however, this information is not available, he must first produce coefficients based upon experience and, after refining them, check the results by calculation.Training

There are four major requirements for a good naval architect.The first is a clear understanding of the fundamental principles of applied science, particularly those aspects of science that have direct application to ships------mathematics, physics, mechanics, fluid mechanics, materials, structural strength, stability, resistance, and propulsion.The second is a detailed knowledge of past and present practice in shipbuilding.The third is personal experience of accepted methods in the design, construction, and operation of ships;and the fourth, and perhaps most important, is an aptitude for tackling new technical problems and of devising practical solutions.The professional training of naval architects differs widely in the various maritime countries.Unimany universities and polytechnic schools;such academic training must be supplemented by practical experience in a shipyard.Trends in design The introduction of calculating machines and computers has facilitated the complex calculations required in naval architecture and has also introduced new concepts in design.There are many combinations of length, breadth, and draft that will give a required displacement.Electronic computers make it possible to prepare series of designs for a vessel to operate in a particular service and to assess the economic returns to the shipowner for each separate design.Such a procedure is best carried out as a joint exercise by owner and builder.As ships increase in size and cost, such combined technical and economic studies can be expected to become more common.(From ―Encyclopedia Britannica‖, Vol.16, 1980)

Technical terms

1.naval architect 造船工程（设计）师 32.scantling 结构（件）尺寸

naval architecture造船（工程）学 33.frame 肋骨 2.instruction 任务书、指导书 34.classification society 船级社 3.oil tanker 油轮 35.steering 操舵、驾驶 4.deadweight 载重量 36.vibration 振动 5.knot 节 37.net register tonnage 净登记吨位 6.specification 规格书，设计任务书 38.harbour 港口 7.vessel 船舶 39.dues 税收 8.cargo 货物 40.gross tonnage 总吨位 9.passenger 旅客 41.deductible space 扣除空间 10.trade 贸易 42.revenue 收入 11.machinery 机械、机器 43.docking 进坞 12.hold capacity 舱容 44.charge 费用、电荷 13.consumable store 消耗物品 45.bulkhead 舱壁 14.light weight 轻载重量、空船重量 46.subdivision分舱（隔）、细分 15.hull 船体 47.collision 碰撞 16.dimension 尺度、量纲、维（数）48.compromise 折衷、调和 17.displacement 排水量、位移、置换 49.coefficient 系数 18.tonnage 吨位 50.training 培训 19.fineness 纤瘦度 51.fluid mechanics 流体力学 20.draft 吃水 52.structural strength 结构强度 21.breadth 船宽 53.resistance 阻力 22.freeboard 干舷 54.propulsion 推进 23.rule 规范 55.shipbuilding 造船 24.tentative 试用（暂行）的 56.aptitude（特殊）才能，适应性 25.longitudinal direction 纵向 57.maritime 航运，海运 26.vertical direction 垂向 58.polytechnical school 工艺（科技）学校 27.trim 纵倾 59.academic 学术的 28.stability 稳性 60.shipyard 造船厂 29.shaft horse power 轴马力 61.electronic computer 电子计算机 30.strength 强度 62.owner 船主，物主 31.service 航区、服务 63.encyclop(a)edia 百科全书

Additional Terms and Expressions 1.the Chinese Society of Naval Architecture and Marine Engineering(CSNAME)中国造船工程学会

the Chinese Society of Navigation中国航海学会

“Shipbuilding of China‖ 中国造船 Ship Engineering 船舶工程

“Naval 安定Merchant Ships” 舰船知识

China State Shipbuilding Corporation(CSSC)中国船舶工业总公司

China offshore Platform Engineering Corporation(COPECO)中国海洋石油平台工程公司

Royal Institution of Naval Architects(RINA)英国皇家造船工程师学会

Society of Naval Architects and Marine Engineers(SNAME)美国造船师与轮机工程师协会

10.Principle of naval architecture 造船原理 11.ship statics(or statics of naval

architecture)造船静力学 12.ship dynamics 船舶动力学

13.ship resistance and propulsion 船舶阻力

和推进

14.ship rolling and pitching 船舶摇摆 15.ship manoeuvrability 船舶操纵性 16.ship construction 船舶结构

17.ship structural mechanics 船舶结构力学 18.ship strength and structural design 船舶

强度和结构设计

19.ship design 船舶设计

20.shipbuilding technology 造船工艺

21.marine(or ocean)engineering 海洋工程 2.3.4.5.6.7.8.9.Note to the Text

1.range from A to B 的意思为“从A到B的范围内”，翻译时，根据这个基本意思可以按汉语习惯译成中文。例：

Lathe sizes range from very little lathes with the length of the bed in several inches to very large ones turning a work many feet in length.车床有大有小，小的车床其车身只有几英寸，大的车床能车削数英尺长的工件。

2.Such that 可以认为是such a kind/value 等的缩写，意思为“这样的类别/值等……以至于……”。译成中文是，可根据具体情况加以意译。例：

The depth of the chain locker is such that the cable is easily stowed.锚链舱的深度应该使锚链容易存储。

Possessing an attractive appearance, the ship should have the minimum net register tonnage,the factor on which harbour and oyher dues are based.Possessing an attractive appearance现在分词短语，用作表示条件的状语，意译成“船舶除有一个漂亮的外形……”。一般说，如分词短语谓语句首，通常表示时间、条件、原因等。

The factor on which…are based中的the factor是前面the minimum net register tonnage的铜谓语，而on which…are based是定语从句，修饰the factor。

4.Electronic computers make it possible to prepare series id designs for a vessel to operate in a particular service and to assess the economic returns to the shipowner for each separate design.句中的it是形式宾语，实际宾语为不定式短语 to prepare series of designs …和to assess the economic returns …

Lesson Two

Definitions, Principal Dimensions Before studying in detail the various technical branches of naval architecture it is important to define chapters.The purpose of this chapter is to explain these terms and to familiarise the reader with them.In the first place the dimensions by which the size of a ship is measured will be considered;they are referred to as ‗principal dimensions‘.The ship, like any solid body, requires three dimensions to define its size, and these are a length, a breadth and a depth.Each of these will be considered in turn.Principal dimensions Length There are various ways of defining the length of a ship, but first the length between perpendiculars will be considered.The length between perpendiculars is the distance measured parallel to the base at the level of the summer load waterline from the after perpendicular to the forward perpendicular.The after perpendicular is taken as the after side of the rudder post where there is such a post, and the forward perpendicular is the vertical line drawn through the intersection of the stem with summer load waterline.In ships where there is no rudder post the after perpendicular is taken as the line passing through the centre line of the rudder pintals.The perpendiculars and the length between perpendiculars are shown in Figure 1.The length between perpendiculars(LBP)is used for calculation purposes as will be seen later, but it will be obvious from Figure 1 that this does not represent the greatest length of the ship.For many purposes, such as the docking of a ship, it is necessary to know what the greatest length of the ship is.This length is known as the length of the extreme point at the after end to a similar point at the forward end.This can be clearly seen by referring again to Figure 1.In most ships the length overall will exceed by a considerable amount the length between perpendiculars.The excess will include the overhang of the stern and also that of the stem where the stem is raked forward.In modern ships having large bulbous bows the length overall LOA may have to be measured to the extreme point of the bulb.A third length which is often used, particularly when dealing with ship resistance, is the length on the waterline LWL.This is the distance measured on the waterline at which the ship is floating from the intersection of the stern with the waterline to the length is not a fixed quantity for a particular ship, as it will depend upon the waterline at which the ship is floating and upon the trim of the ship.This length is also shown in Figure 1.6 Breadth The mid point of the length between perpendiculars is called ‗amidships‘and the ship is usually broadest at this point.The breadth is measured at this position and the breadth most commonly used is called the ‗breadth moulded‘.It may be defined simply as the distance from the inside of plating on one side to a similar point on the other side measured at the broadest part of the ship.As is the case in the length between perpendiculars, the breadth moulded dose not represent the greatest breadth the breadth extreme is required(see Figure 2).In many ships the breadth extreme is the breadth moulded plus the thickness of the shell plating where the strakes of shell plating were overlapped the breadth extreme was equal to the breadth moulded plus four thicknesses of shell plating, but in the case of modern welded ships the extra breadth consists of two thicknesses of shell plating only.The breadth extreme may be much greater than this in some ships, since it is the distance from the extreme overhang on one side of the ship to a similar point on the other side.This distance would include the overhang of decks, a feature which is sometimes found in passenger ships in order to provide additional deck area.It would be measured over fenders, which are sometimes fitted to ships such as cross channel vessels which have to operate in and out of port under their own power and have fenders provided to protect the sides of the ships when coming alongside quays.Depth The third principal dimension is depth, which varies along the length of the ship but is usually measured ant amidships.This depth is known as the ‗depth moulded and is measured from the underside of the plating of the deck at side amidships to the base line.It is shown in Figure 2(a).It is sometimes quoted as a ‗depth moulded to upper deck‘ or ‗depth moulded to second deck‘, etc.Where no deck is specified it can be taken the depth is measured to the uppermost continuous deck.In some modern ships there is a rounded gunwale as shown in Figure 2(b).In such cases the depth moulded is measured from the intersection of the deck line continued with the breadth moulded line.Other features

The three principal dimensions give a general idea of the size of a ship but there are several other features which have to be considered and which could be different in two ships having the same length, breadth and depth.The more important of these will now be defined.Sheer Sheer is the height of the deck at side above a line drawn parallel to the base and tangent to the length of the ship and is usually greatest at the ends.In modern ships the deck line at side often has a variety of shapes: it may be flat with zero sheer over some distance on either side of amidships and then rise as a straight line towards the ends;on the other hand there may be no sheer at all on the deck, which will then be parallel to the base over the entire length.In older ships the deck at side line was parabolic in profile and the sheer was quoted as its value on the forward and after perpendiculars as shown in Figure 1.So called ‗standard‘ sheer was given by the formulae:

Sheer forward(in)=0.2Lft+20 Sheer aft

(in)=0.1Lft+10 These two formulae in terms of metric units would give:

Sheer forward

(cm)=1.666Lm+50.8 Sheer aft

(cm)=0.833Lm+25.4 It will be seen that the sheer forward is twice as much as the sheer aft in these standard formulae.It was often the case, however, that considerable variation was made from these standard values.Sometimes the sheer forward was increased while the sheer after was reduced.Occasionally the lowest point of the upper deck was some distance aft of amidships and sometimes departures were made from the parabolic sheer profile.The value of sheer and particularly the sheer forward was to increase the height of the deck above water(the ‗height of platform‘ as it was called)and this helped to prevent water being shipped when the vessel was moving through rough sea.The reason for the abolition of sheer in some modern ships is that their depths are so great that additional height of the deck above water at the fore end is unnecessary from a seakeeping point of view.Deletion of sheer also tends to make the ship easier to construct, but on the other hand it could be said that the appearance of the ship suffers in consequence.Camber Camber or round of beam is beam is defined as the rise of the deck of the ship in going from the side to the centre as shown in Figure 3(a).The camber curve used to be parabolic but here again often nowadays straight line camber curves are used or there may be no camber at all on decks.Camber is useful on the weather deck of a ship from a drainage point of view, but this may not be very important since the ship is very rarely upright and at rest.Often, if the weather deck of a ship is cambered, the lower decks particularly in passenger ships may have no camber at all, as this makes for horizontal decks in accommodation which is an advantage.Camber is usually stated as its value on the moulded breadth of the ship and standard camber was taken as one-fiftieth of the breadth.The camber on the deck diminishes towards the ends of the ship as the deck breadths become smaller.Bilge radius An outline of the midship section of a ship is shown in Figure 3(a).In many ‗full‘ cargo ships the section is virtually a rectangle with the lower corners rounded off.This part of the section is referred to as the ‗bilge‘ and the shape is often circular at this position.The radius of the circular arc forming the bilge is called the ‗bilge radius‘.Some designers prefer to make the section some curve other than a circle in way of the bilge.The curve would have a radius of curvature which increases as it approaches the straight parts of the section with which it has to link up.Rise of floor The bottom of a ship at amidships is usually flat but is not necessarily horizontal.If the line of the flat bottom is continued outwards it will intersect the breadth moulded line as shown in Figure 3(a).The height of this intersection above base is called the ‗rise of floor ‘.The rise of floor is very much dependent on the ship form.In ships of full form such as cargo ships the rise of floor may only be a few centimeters or may be eliminated altogether.In fine form ships much bigger rise of floor would be adopted in association with a larger bilge radius.Flat of keel

A feature which was common in the days of riveted ships what was known as ‗flat of keel ‘ or ‗flat of bottom ‘.Where there is no rise of floor, of course, the bottom is flat from the centre line to the point where the curve of the bilge starts.If there was a rise of floor it was customary for the line of the bottom to intersect the base line some distance from the centre line so that on either side of the centre line there was a small portion of the bottom which was horizontal, as shown in Figure 3(a).this was known as the ‗flat of bottom‘ and its value lay in the fact that a rightangle connection could be made between the flat plate keel and the vertical centre girder and this connection could be accomplished without having to bevel the connecting angle bars.Tumble home Another feature of the midship section of a ship which was at one time quite common but has now almost completely disappeared is what was called ‗tumble home‘.This is the amount which the side of the ship falls in from the breadth moulded line, as shown in Figure 3(b).Tumble home was a usual feature in sailing ships and often appeared in steel merchant ships before World War II.Ships of the present day rarely employ this feature since its elimination makes for ease of production and it is of doubtful value.Rake of stem In ships which have straight stems formed by a stem bar or a plate the inclination of the stem to the vertical is called the ‗rake‘.It may be defined either by the angle to the vertical or the distance between the intersection of the stem produced with the base line and the forward perpendicular.When ships have curved stems in profile, and especially where they also have bulbous bows, stem rake cannot be simply defined and it would be necessary to define the stem profile by a number of ordinates at different waterlines.In the case of a simple straight stem the stem line is usually joined up with the base line by a circular are, but sometimes a curve of some other form is used, in which case several ordinates are required to define its shape.Draught and trim The draught at which a ship floats is simply the distance from the bottom of the ship to the waterline.If the waterline is parallel to the keel the ship is said to be floating on an even keel, but if the waterline is not parallel then the ship is said to be trimmed.If the draught at the after end is greater than that at the fore end the ship is trimmed by the stern and if the converse is the case it is trimmed by the bow or by the head.The draught can be measured in two ways, either as a moulded draught which is the distance from the base line to the waterline, or as an extreme draught which is the distance from the bottom of the ship to the waterline.In the modern welded merchant ship to the waterline.In the modern welded merchant ship these two draughts differ only by one thickness of plating, but in certain types of ships where, say, a bar keel is fitted the extreme draught would be measured to the underside of the keel and may exceed the moulded draught of by 15-23cm(6-9in).It is important to know the draught of a ship, or how much water the ship is ‗drawing‘, and so that the draught may be readily obtained draught marks are cut in the stem and the stern.These are 6 in high with a space of 6in between the top of one figure and the bottom of the next one.When the water level is up to the bottom of a particular figure the draught in feet has the value of that figure.If metric units are used then the figures would probably be 10 cm high with a 10 cm spacing.In many large vessels the structure bends in the longitudinal vertical plane even in still water, with the result that the base line or the keel does not remain a straight line.The mean draught at which the vessel is floating is not then simply obtained by taking half the sum of the forward and after draughts.To ascertain how much the vessel is hogging or sagging a set of draught marks is placed amidships so that if da, d and df are the draughts at the after end amidships and the forward end respectively then

Hog or sag=

dadf-d

2When use is made of amidship draughts it is necessary to measure the draught on both sides of the ship and take the mean of the two readings in case the ship should be heeled one side or the other.The difference between the forward and after draughts of s ship is called the ‗trim‘, so that trim T=da-df, and as previously stated the ship will the said to be trimming by the stern or the bow according as the draught aft or the draught forward is in excess.For a given total load on the ship the draught will have its least value when the ship is on an even keel.This is an important point when a ship is navigating in restricted depth of water or when entering a dry dock.Usually a ship should be designed to float on an even keel in the fully loaded condition, and if this is not attainable a small trim by the stern is aimed at.Trim by the bow is not considered desirable and should be avoided as it reduces the ‗height of platform‘ forward and increases the liability to take water on board in rough seas.Freeboard Freeboard may be defined as the distance which the ship projects above the surface of the water or the distance measured downwards from the deck to the waterline.The freeboard to the weather deck, for example, will vary along the length of the ship because of the sheer of the deck and will also be affected by the trim, if any.Usually the freeboard will be a minimum at amidships and will increase towards the ends.Freeboard has an important influence on the seaworthiness of a ship.The greater the freeboard the greater is the above water volume, and this volume provides reserve buoyancy, assisting the ship to rise when it goes through waves.The above water volume can also help the ship to remain afloat in the event of damage.It will be seen later that freeboard has an important influence on the range of stability.Minimum freeboards are laid down for ships under International Law in the form of Load Line Regulations.(from ―Naval Architecture for Marine Engineers‖ by W.Muckle, 1975)

Technical Terms

1.principal dimension 主要尺度

2.naval architecture 造船（工程）学 3.造船工程（设计）师

4.length between perpendiculars(LBP)垂线间长 5.summer load waterline 夏季载重水线 6.forward/after perpendicular 首/尾垂线 7.rudder post 尾柱 8.stem 首柱

9.rudder pintle 舵销

10.length over all(LOA)总长

11.overhang（水线以上）悬伸部分 12.bulbous bow 球鼻艏

13.length on the waterline（LWL）水线长 14.amidship 船中

15.breath moulded 型宽 16.breath extreme 最大船宽 17.shell plating 船壳板 18.rivet 铆接 19.weld 焊接

20.strake（船壳板）列板 21.fender 护舷木

22.deck area 甲板面积（区域）23.cross channel vessel 海峡船 24.port 港口，船的左舷 25.side 舷侧（边）26.quay 码头

27.depth moulded 型深 28.plating of deck 甲板板 29.base line 基线 30.upper deck 上甲板 31.second deck 第二甲板

32.the uppermost continuous deck 最上层连续甲板 33.rounded gunwale 圆弧舷边顶部 34.moulded line 型线 35.sheer 舷弧 36.ends 船端

37.deck line at side 甲板边线 deck at side line 甲板边线 deck at side

甲板边线 38.profile

纵剖面（图），轮廓 39.sheer forward/aft 首/尾舷 40.platform

平台

41.rough sea

强浪，汹涛海面 42.seakeeping

耐波性

43.appearance

外形（观），出现 44.camber

梁拱

round of beam 梁拱 45.weather deck 露天甲板 46.drainage 排水

47.upright 正浮，直立 48.at rest 在静水中

49.accommodation 居住舱，适应 50.bilge radius

舭（部）半径 5.1 midship section 船中剖面 52.bilge

舭（部）53.rise of floor 船底升高 54.flat of keel 龙骨宽 55.flat plate keel平板龙骨 56.vertical center girder 中桁材

57.bevel

折射角，将直角钢改为斜角 58.connecting angle 联接角钢

59.tumble home 内倾 60.sailing ship 帆船

61.steel merchant ship 钢质商船 62.bar 棒，巴（气压单位）63.rake 倾斜

64.draught 吃水，草图，通风 65.even keel 等吃水，正浮

66.trimmed by the stern/bow 尾/首倾 67.moulded draught 型吃水 68.extreme draught 最大吃水 69.bar keel 棒龙骨 70.‖drawing‖“吃水” 71.draught marks 吃水标志 72.imperial unit 英制单位 73.metric unit 公制单位 74.spacing 间距 75.hogging 中拱 76.sagging 中垂 77.heel

横倾 78.dry dock 干船坞

79.fully loaded condition 满载标志 80.freeboard 干舷

81.seaworthiness 适航性

82.reserve buoyancy 储备浮力 83.range of stability 稳性范围

84.Load Line Regulations 载重线规范

Additional Terms and Expressions

1.form coefficients 船型系数 2.block coefficient 方型系数 3.prismatic coefficient 棱型系数

4.midship area coefficient 船中横剖面面积系数

5.waterplane area coefficient 水线面面积系数

6.vertical prismatic coefficient 竖向棱型系数 7.body section of U-form U形横剖面 8.V-shaped section V形横剖面

9.geometrically similar ships 几何相似船 10.base plane 基平面

11.center plane 中线面 12.midstation plane 中站面 13.moulded base line 基线 14.length breadth ratio 长度比 15.cruiser stern 巡洋舰型尾

16.principal coordinate planes 主坐标面 17.transom 方尾 18.soft chine 圆舭 19.hard chine 尖舭 20.counter 尾伸部 21.forefoot 首踵 22.aftfoot 尾踵

23.deadwood 尾鳍（呆木）

Notes to the Text

1.as will be seen later 和as is the case in the length between perpendiculars 中as 引出的从句为非限制性定语从句。关系代词as代替整个主句，并在从主语中作主语。as 也可在从句中作宾语，表语用。

2.A third length 序数字前面，一般用定冠词“the”，但当作者心目中对事物总数还不明确，或还不足以形成一个明确的序列时，序数字前面用不定冠词“a”。例：

will they have to modify the design a fourth time?(它们的设计究竟要修改多少次，心中无数，但依次下来已是第四次，所以用不定冠词“a”。)3.This is the distance measured on the waterline at which the ship is floating from the intersection of the stern with the waterline to the intersection of the stem with the waterline.这是一个符合据。其中at which the ship is floating 为定语从句，修饰the waterline.from the intersection of the stern(with the waterline为intersection 所要求的介词短语)to the intersection of the stern(with the waterline 为第二个intersection 所要求的介词短语）都属于介词短语，作状语用，说明测量的范围。

4.参见第一课注3.中的第二部分说明 5.quay 一般指与海岸平行的码头

pier 系指与海岸或呈直角面突出的码头

wharf 一般用于的码头

6.the deck line continued 和the stern produced 为过去分词作后置定语，分别修饰“the deck line 和the stern.都可译成“延长时”。

considerable variation was made from these standard values 和departures were made from the parabolic sheer profile 和（when）use is made of amidship draughts 这三句都属于主语的成分被位于动词隔离成两部分。这是英语句子结构平衡的需要中带有这种情况，阅读和翻译时需加以注意。

7.considerable variation was made from these standard values 和departures were made from the parabolic sheer profile 和（when）use is made of amidship draughts 这三句都属于主语的成分被位于动词隔离成两部分。这是英语句子结构平衡的需要中带有这种情况，阅读和翻译时需加以注意。Lesson Three

Merchant ship Types Break-bulk cargo ships

The inboard space in break bulk cargo ships is divided longitudinally by transverse bulkheads, spaced 40-70 ft apart, into a series of cargo compartments of approximately equal volume, generally seven for a ship of about 500 ft Lap.Vertically, the bulkheads are divided by one or two decks below the uppermost, continuous deck(main or strength deck).The space between the inner bottom and the lowest deck, called the hold, is limited to a height of about 18 ft(5.5m)to minimize damage to cargo through crushing.Usually the height of each space between decks termed between deck space)is 9-10ft(2.7-3.0m).In addition to the previously mentioned double-bottom tanks, the most break-bulk cargo ships have deep tanks used for fuel oil, water ballast, or liquid cargoes such as latex, coconut oil, or edible oils.The cargo is handled through large rectangular deck openings(hatches)over each cargo space.Mechanically operated hatch covers are used to close the openings.The hatch covers in the tween decks are strong enough to support cargo stowed on them.The topside hatch covers are watertight.The tween deck space is generally suitable for break-bulk or palletized cargo holds have had one hatch per deck, with of 35-50% the ship‘s breath and a length of 50-60% the hold length.The trend is toward widen hatches or multiple hatches abreast and often longer hatches, to increase cargo handling speed.A multiple hatch arrangement(triple hatch, for instance)is efficiently used for a partial load of containers stowed under deck.Break-bulk cargo handling between pier and ship is done usually by means of cargo booms installed on board.The booms are raised or lowered by adjustable wire rigging led from the mast or king post to the boom ends.A wire rope leads over sheaves from a winch to the outer end of each boom and terminates in a cargo hook.Cargo can be hoisted using one boom(customarily for very heavy loads of cargo, 10 tons or over)or for faster handling, by a pair of married booms, with one boom end over the hatch and the other over the pier.This cargo handling operation, called burtoning, is customary for loads up to 10 tons.Most break-bulk cargo ships fitted with booms have a pair of booms at each hatch end to expedite cargo handling.The cargo is often piled together in a large net which is emptied and returned for the next load.Packaged cargo of nearly uniform dimensions may be stacked on pallets which are hoisted aboard individually.The sling load is landed through the hatch opening.The pallets or nets are then unloaded, and each item is individually stowed by the hold gang.Any cargo stowed in the wings of the hold is manhandled unless it is on pallets and handled by a forklift truck.The use of forklift trucks is becoming common practice, and a number of these trucks may be carried on board if they are not available at cargo terminals.The amount of cargo which is manhandled onboard determines largely the ship turnaround and port expenses, and, the profitability of the transportation system.Most break-bulk cargo ships have provisions for a heavy lift boom of 30-100-metric ton capacity for occasional units of heavy cargo.An increasing number of break-bulk cargo ships are being fitted with revolving deck cargo cranes instead of masts, booms and winches.Container ships

Container ships are replacing the conventional break-bulk cargo ship in trade routes where rapid cargo handling is essential.Containers are weatherproof boxes(usually metal)strengthened withstand stacking and motion at sea.Containers are of standard size, the largest ones weighing up to about 30 metric tons when loaded.The use of standard containers facilitates ship-board stowage, land or waterway transportation, and rental or lease.A large container ship may be loaded or unloaded completely in about half a day, compared to several days for the same amount of cargo in break-bulk cargo ship.Generally, the shipper places the cargo in the container and，except for custom inspection, it is delivered unopened to the consignee.Highway trailers(most commonly), railroad cars, or barges transport containers to and from their land destination and are therefore apart of the same transportation system.For a given payload cargo capacity, container ships are larger and more costly to build than the traditional cargo ship, but both the cargo handling cost and the idle ship time in port are reduced considerably.Although in some ships containers are moved horizontally for loading and unloading, the predominant arrangement is that illustrated in Fig.1 where containers are stowed in vertical cells and moved vertically in and out of the vessel.Roll-on/Roll-off ships

With a broad interpretation all ships that are designed to handle cargo by rolling it on wheels can be considered under this heading.This would include trailer ships;sea trains(carrying railroad cars or entire carriers: ships carrying pallets handled by forklift trucks from and to shore;and so on, the following is a description of a ship of this type, which is intended primarily to operate as a trailer ship, although it may handle several types of wheeled vehicles.Roll-on/Roll-off ships require a high proportion of cubic capacity relative to the amount of cargo and are particularly suited to services with short runs and frequent loading and unloading.They need even shorter port time than container ships but their building cost is higher.Because fully loaded toll-on/roll-off ships can not carry enough cargo to immerse them deeply, their large freeboard allows the fitting of side ports above the waterline for handling of cargo on wheels by means of ramps.Usually, ships of this type have a transom stern(a square-shaped stern like that of a motorboat)fitted with doors for handling wheeled vehicles on an aft ramp.Roll-on/Roll-off ships have several decks, and the cargo is handled on wheels from the loading deck to other decks by elevators or sloping ramps.Both internal elevators and ramps occupy substantial volume in the ship.The need for clear decks, without interruption by transverse bulkheads, and tween decks for vehicle parking results in a unique structural arrangement.Barge-carrying ships

This type of ship represents a hold step in the trend toward cargo containerization and port time reductions.Cargo is carried in barges or lighters each weighing up to 1000 metric tons when loaded.The lighters are carried below and above deck and handled by gantry cranes or elevator platforms.These are among the fastest, largest, and costest ships for the carriage of general cargo.For their size, their payload capacity is less than that of the conventional break-bulk cargo ship.However, they can be loaded and unloaded much faster and with a considerable saving in man-hours.Because the lighters can be waterborne and operated as regular barges, these large ships can serve undeveloped ports advantageously.Using portable fixtures that can be erected quickly, barge-carrying ships can be adapted for the transport of varying amounts of standard containers in addition to or in plane of lighters.Bulk cargo ships

A large proportion of ocean transportation is effected by bulk cargo ships.Dry bulk cargo includes products such as iron ore, coal, limestone, grain, cement, bauxite gypsum, and sugar.Most oceangoing dry bulk carriers are loaded and unloaded using shore side installations.Many dry bulk carriers operating in the Great Lakes have shipboard equipment for the handling of cargo(self-unloaders), and an increasing number of oceangoing ships carrying this type of cargo are being fitted with self-unloading gear.By far the largest amount of liquid bulk cargo consists of petroleum products, but ocean transportation of other bulk liquid products is increasing in importance;for example, various chemicals, vegetable oils, molasses, latex, liquefied gases, molten sulfur, and even wine and fruit juices.Practically all liquid bulk carriers have pumps for unloading the cargo, usually have ship board pumps for unloading liquids.Practically all bulk carriers have the machinery compartment, crew accommodations, and conning stations located aft.An exception is the Great Lakes self-unloader with crew accommodations and bridge forward.The tendency in bulk carriers is toward larger ships, with speeds remaining about constant at moderate level(16-18 knots or 30-33 km/h for oceangoing ships, lower for Great Lakes vessels).The oceangoing ore carrier is characterized by a high double bottom and small volume of cargo hold because of the high density of the ore.Storing the cargo high in the ship decreases stability and prevents excessively quick rolling.The oceangoing combination bulk carrier permits low-cost transportation because of its flexibility.It is able to carry many types of bulk cargoes over a variety of sea lanes.This type of ship carries bulk cargoes, such as petroleum product, coal, grain, and ore.The double bottom in bulk carriers is shallow and the volume of cargo holds is large compared to the size of the ship.The tanker is the characteristic, and by far the most important, liquid bulk carrier both in numbers and tonnage.Tankers carry petroleum products almost exclusively.The very large tankers are used almost entirely for the transport of crude oil.A few tankers are built especially for the transportation of chemical products, and others are prepared for alter native loads of grain.Bulk liquid carriers, with standing, rectangular, cylindrical, or spherical cargo tanks separated from the hull, are used for the transportation of molten sulfur and liquefied gases, such as anhydrous ammonia and natural gas.Liquefied natural gas(LNG)is also carried in ships with membrane tanks, i.e., where a thin metallic linear is fitted into a tank composed of ship structural and load-bearing insulation.The transportation of molten surfur and liquefied gases requires special consideration regarding insulation and high structural soundness of cargo tanks, including the use of high grade, costly materials for their construction.(From ―McGraw-Hill Encyclopedia of Science and Technology‖, Vol.8.1982).Passenger-cargo ships

The accommodations for passengers in this type of ship are located to assure maximum comfort.Generally a passenger-cargo ship serves ports that have an appeal for the tourist trade and where rather special, high freight-rate cargo is handled.Because of the service needs of passengers, a ship of this type requires a much larger crew than a merchant ship of comparable size engaged exclusively in the carriage of cargo.The living accommodations for passengers consist of staterooms with 1-4 berths, each room with bath and toilet.A few rooms may be connected and suites may include a living room, dressing room, and even a private outdoor veranda.Public rooms for passenger use may include dining room, lounge, cocktail room, card and game room, library, shops, and swimming pool.Ships carrying more than 12 passengers must comply with the SOLAS regulations.These regulations deal with ship characteristics related to items such as the following:(1)lessening the risk of foundering or capsizing due to hull damage,(2)preventing the start and spread of fires aboard, and(3)increasing the possibility and safety of abandoning ship in emergencies.The ship in Fig.2 is an interesting example of a departure from the traditional break-bulk cargo ship in which cargo is handled almost exclusively by means of a ship board installation of masts and booms.This ship is provided with gantry cranes to handle containers, vehicles, and large pallets.The containers may be stored in cargo holds equipped with container cells or on deck.Large-size pallets and vehicles may be handled through side ports by means of an athwart-ship gear called a siporter.Wheeled vehicles can also be rolled on and off the ship through the side ports.Cargo may be carried to and from lower decks by cargo elevators, and, in addition, there are vertical conveyors for handling cargo such as bananas.The horizontal conveyors shown in the typical section receive cargo automatically, mostly on pallets, from the cargo elevators.This cargo is then stowed by manually controlled, battery operated pallet loaders.Cargo for the forward hold is handled by a 5-ton burtoning cargo gear and transferred to lower levels by a cargo elevator.(From ―McGraw – Hill Encyclopedia of Science and Technology‖, Vol.12, 1977)

Technical Terms

1.break-bulk cargo ship 件杂货船 26.king post 吊杆柱，起重柱 2.inboard 船内 27.wire rope 钢丝绳 3.compartment 舱室 28.sheave

滑轮 4.transverse bulkhead 横舱壁 29.winch 绞车 5.main deck 主甲板 30.cargo hook 吊货钩 6.strength deck 强力甲板 31.married booms 联合吊杆 7.inner bottom 内底 32.burtoning 双杆操作 8.hold(cargo hold)货舱 33.cargo handling 货物装卸 9.tween deck space 甲板间舱 34.packaged cargo 包装货 10.double bottom 双层底 35.pallet 货盘 11.deep tank 深舱 36.sling load

悬吊荷重 12.water ballast 水压载 37.hold gang 货舱理货组 13.latex 胶乳 38.wings 货舱两侧 14.coconut oil 椰子油 39.forklift truck 铲车 15.edible oil 食用油 40.terminal 码头，终端 17.hatch 舱口 41.turnaround 周转期 18.hatch cover 舱口盖 42.profitability 利益 19.palletized cargo 货盘运货 43.container ship 集装箱船 20.multiple hatch 多舱口 44.trade route 贸易航线 21.abreast 并排 45.weather proof 风雨密 22.container 集装箱 46.stacking 堆压 23.pier 码头 47.stowage 装载，贮藏 24.cargo boom 吊货杆 48.waterway 水路 25.wire rigging 钢索索具 49.rental 出租（费）50.lease 租借 51.shipper 货运主 52.custom 海关

53.consignee 收货人

54.highway trailer 公路拖车

55.payload 净载重量，有效载荷 56.cell 格栅，电池，元件 57.roll-on/roll-off ship 滚装船 58.heading 标题，航向 59.trailer ships 拖车运输船

60.sea trains ferry 海上火车渡船 61.truck 卡车 62.trailer 拖车

63.military vehicle carriers 军用车辆运输船

64.cubic capacity 舱容 65.ramp 跳板，坡道 66.transom stern 方尾

67.motor boat 机动艇，汽艇 68.clear deck 畅通甲板 69.parking 停车（场）

70.barge-carrying ship 载驳船 71.lighter 港驳船 72.barge 驳船

73.portable fixture 轻便固定装置

74.bulk cargo ship/bulk carrier 散装货船 75.dry bulk cargo 散装干货 76.limestone 石灰石 77.bauxite 矾土 78.gypsum 石膏

79.Great Lakes（美国）大湖 80.petroleum 石油

81.chemicals 化学制（产）品 82.molasses 糖浆

83.liquefied gas 液化气体 84.molten sulfur 熔态硫 85.conning station 驾驶室

86.ore hold 矿砂舱 87.空

88.engine room 机舱

89.liquid bulk carrier 液体散货船

90.combination bulk carrier 混装散货船 91.ocean-going ore carrier 远洋矿砂船 92.lane 航道（线）93.tanker 油船 94.crude oil 原油

95.anhydrous ammonia 无水氨 96.natural gas 天然气

97.passenger-cargo ship 客货船 98.tourist 旅游者 99.freight-rate 运费率

100.carriage 装（载）运，车辆 101.stateroom 客舱 102.suite 套间

103.living room 卧室 104.veranda 阳台 105.lounge 休息室

106.cocktail room 酒吧间

107.card and game room 牌戏娱乐室 108.foundering 沉没 109.capsizing 倾覆 110.abandoning 弃船 111.emergency 应急

112.installation 装置，运载工具 113.vehicle 车辆，运载工具 114.gantry crane 门式起重机 115.container cell 集装箱格栅 116.siporter 横向装卸机

117.rolled on and off 滚进滚出 118.side port 舷门

119.cargo elevator 运货升降机 120.conveyor 输送机

Additional Terms and Expressions 1.2.3.4.transport ship 运输船 general cargo ship 杂货船 liquid cargo ship 液货船 refrigerated ship 冷藏船

5.6.7.8.working ship 工程船

ocean development ship 海洋开发船 dredger 挖泥船

floating crane/derrick boat 起重船 9.salvage vessel 救捞船 10.submersible 潜水器 11.ice-breaker 破冰船 12.fisheries vessel 渔业船 13.trawler 拖网渔船

seine netter 围网渔船 14.harbour boat 港务船 15.supply ship 供应船 16.pleasure yacht 游艇

17.hydrofoil craft 水翼艇 18.air-cushion vehicle 气垫船

hovercraft 全垫升气垫船 19.catamaran 双体船 20.concrete ship 水泥船

21.fiberglass reinforced plastic boat 玻璃钢

艇

Notes to the Text

1.unless 连接词，作“如果不”，“除非”解释，例如：

An object remain at rest or moves in a straight line unless a force acts upon it.一个物体如无外力作用，它将继续保持静止或作直线运动。

In this book the word is used in its original sense unless(it is)otherwise sated.本书内，这个词按其意采用，除非另有说明。2.“to and from 名词”或“from and to +名词” 后面的名词委前面两个介词公用，可译作“来回于（名词）之间”。

3.with a broad interpretation 具有广泛的意思

under this heading 属于这个范畴

4.barge 和lighter 一般都可以译作驳船，但barge 往往指货物经过较长距离运输到达某一目的地，故译作“驳船”，而lighter 旨在港口或近距离内起到装卸货物的联络作用，故译作“驳船”。

5.in additional to or in place of lighters 是in addition to lighters or in place of lighters 的省略形式，翻译成中文时，不一定能省略。

6.“by far +形容词（或副词）的最高级或比较及”具有“远远，非常，最„，或„得多”的意思。例：

by far the fastest 最快的

by far faster than A 远比A快（比A 快得多）

By far the most common type of fixed offshore structure in existence today is the template, or jacket, structure illustrated in Fig 1.1.现今最普遍采用的固定平台型式是图1.1所示的导管架平台。

7.the SOLAS regulations 系指国际海上人命安全公约规则，几乎所有海运国家都要遵守这些规则。其中的“SOLAS”为“International Convention for the Safety Of Life At Sea‖的缩写。Lesson Four

Ship Design

The design of a ship involves a selection of the features of form, size, proportions, and other factors which are open to choice, in combination with those features which are imposed by circumstances beyond the control of the design naval architect.Each new ship should do some things better than any other ship.This superiority must be developed in the evolution of the design, in the use of the most suitable materials, to the application of the best workmanship, and in the application of the basic fundamentals of naval architecture and marine engineering.As sips have increased in size and complexity, plans for building them have became mare detailed and more varied.The intensive research since the period just prior to World War 2 has brought about many technical advances in the design of ships.These changes have been brought about principally by the development of new welding techniques, developments in main propulsion plants, advances in electronics, and changes in materials and methods of construction.All ships have many requirements which are common to all types, whether they are naval, merchant, or special-purpose ships.The first of such requirements is that the ship must be capable of floating when carrying the load for which it was designed.A ship floats because as it sinks into the water it displaces an equal weight of water, and the pressure of the water produces an upward force, which is called the buoyancy force is equal to the weight of the water displaced by the ship and is called the displacement.Displacement is equal to the underwater volume of the ship multiplied by the density of the water in which it is gloating.When floating in still water, the weight of the ship, including everything it carries, is equal to the buoyancy or displacement.The weight of the ship itself is called the light weight.This weight includes the weight of the hull structure, fittings, equipment, propulsion machinery, piping and ventilation, cargo-handling equipment and other items required for the efficient operation of the ship.The load which the ship carries in addition to its own weight is called the deadweight.This includes cargo, passengers, crew and effects, stores, fresh water, feed water for the boilers incase of steam propelling machinery, and other weights which may be part of the ships international load.The sum of all these weights plus the lightweight of the ship gives the total displacement;that is

Displacement = lightweight + deadweight

One of the first things which a designer must do is to determine the weight and size of the ship and decide upon a suitable hull form to provide the necessary buoyancy to support the weight that has been chosen.Owner’s requirements

Ships are designed, built, and operated to fulfill, the requirements and limitations specified by the operator and owner.These owner‘s requirements denote the essential considerations which are to form the basis for the design.They may be generally stated as(1)a specified minimum deadweight carrying capacity,(2)a specified measurement tonnage limit,(3)a selected speed at sea, or a maximum speed on trial, and(4)maximum draft combined with other draft limitations.In addition to these general requirements, there may be a specified distance of travel without refueling and maximum fuel consumption per shaft horsepower hour limitation, as well as other items which will influence the basic design.Apart from these requirements, the ship owner expects the designer to provide a thoroughly efficient ship.Such expectations include(1)minimum displacement on a specified deadweight carrying capacity,(2)maximum cargo capacity on a minimum gross tonnage,(3)appropriate strength of construction,(4)the most efficient type of propelling machinery with due consideration to weight, initial cast, and cost of operation,(5)stability and general seaworthiness, and(6)the best loading and unloading facilities and ample accommodations for stowage.Design procedure

From the specified requirements, an approach is made to the selection of the dimensions, weight, and displacement of the new design.This is a detailed operation, but some rather direct approximations can be made to start the design process.This is usually done by analyzing data available from an existing ship which is closely similar.For example, the design displacement can be approximated from the similar ship‘s known deadweight of, say, 11790 tons and the known design displacement of 17600 tons.From these figures, a deadweight-displacement ratio of 0.67 is obtained.Thus, if the deadweight for the new design is, for example, 10000 tons, then the approximate design displacement will 10,000/0.67 or 15000 tons.This provides a starting point for the first set of length, beam, and draft dimensions, after due consideration to other requirements such as speed, stability, and strength.Beam is defined as the extreme breath of a ship at its widest part, while draft is the depth of the lowest part of the ship below the waterline.Length and speed These factors are related to the hull form, the propulsion machinery, and the propeller design.The hull form is the direct concern of the naval architect, which the propulsion machinery and propeller design are concern.The naval architect has considerable influence on the final decisions regarding the efficiency, weight, and size of the propeller, as both greatly influence the design of the hull form.Speed has an important influence on the length selected for the ship.The speed of the ship is related to the length in term of the ratio V/

L, where V is the speed in knots and L is the effective waterline length of the ship.As the speed-length ratio increases, the resistance of the ship increases.Therefore, in order to obtain an efficient hull form from a resistance standpoint, a suitable length must be selected for minimum resistance.Length in relation to the cross-sectional area of the underwater form(the prismatic coefficient), is also very important insofar as resistance is concerned.Fast ships require fine(slender)forms or relatively low fullness coefficients as compared with relatively slow ships which may be designed with fuller hull forms.Beam and stability

A ship must be stable under all normal conditions of loading and performance at sea.This means that when the ship is inclined from the vertical by some external force, it must return to the vertical when the external force is removed.Stability may be considered in the transverse or in the longitudinal direction.In surface ship, longitudinal stability is much less concern than transverse stability.Submarines, however, are concerned with longitudinal stability in the submerged condition.The transverse stability of a surface ship must be considered in two ways, first at all small angles of inclination, called initial stability, and second at large angles of inclination.Initial stability depends upon two factors,(1)the height of the center gravity of the ship above the base line and(2)the underwater form of the ship.The center of gravity is the point at which the total weight of the ship may be considered to be concentrated.The hull form factor governing stability depends on the beam B, draft T, and the proportions of the underwater and waterline shape.For a given location of the center of gravity, the initial stability of the ship is proportional to B2/T.Beam, therefore, is a primary factor in transeverse stability.At large angles of heel(transeverse inclination)freeboard is also an important factor.Freeboard is the amount the ship projects above the waterline of the ship to certain specified decks(in this case, to the weatherdeck to which the watertight sides extend).Freeboard affects both the size of the maximum righting arm and the range of the stability, that is the angle of inclination at which the ship would capsize if it were inclined beyond that angle.5 Depth an strength

A ship at sea is subjected to many forces because of the action of the waves, the motion of the ship, and the cargo and other weights, which are distributed throughout the length of the ship.These forces produces stresses in the structure, and the structure must be of suitable strength to withstand the action.The determination of the minimum amount of material required for adequate strength is essential to attaining the minimum weight of the hull.The types of structural stress experienced by a ship riding waves at sea are caused by the unequal distribution of the weight and buoyancy throughout the length of ship.The structure as a whole bends in a longitudinal plane, with the maximum bending stresses being found in the bottom and top of the hull girder.Therefore, depth is important because as it is increased, less material is required in the deck and bottom shell.However, there are limits which control the maximum depth in terms of practical arrangement and efficiency of design.(From ―McGraw-Hill Encyclopedia of science and Technology‖, Vol.12, 1982)

Technical Terms

1.form 船型，形状，格式 22.distance of travel 航行距离 2.proportion 尺度比，比例 23.refueling 添加燃料 3.workmanship 工艺质量 24.consumption 消耗 4.basic fundamentals 基本原理 25.initial cost 造价 5.marine engineering 轮机工程 26.cost of operation 营运成本 6.intensive 精致的 27.unloading facility 卸货设备 7.propulsion plants 推进装置 28.cross sectional area 横剖面面积 8.naval ship 军舰 29.fineness 纤瘦度 9.special-purpose ship 特殊用途船 30.prismatic coefficient 菱形系数 10.buoyancy 浮力 31.slender 瘦长（型）11.fittings 配/附件 32.beam 船宽 12.piping 管路 33.inclined 倾斜的 13.ventilation 通风 34.external force 外力 14.cargo-handing equipment 货物装卸装35.surface ship 水面船舶

置 36.submarine 潜水艇 15.crew and effects 船员及自身物品 37.submerged condition 潜水状态 16.stores 储藏物 38.initial stability 初稳性 17.fresh water 淡水 39.weather deck 楼天甲板 18.feed water 给水 40.righting arm 复原力臂 19.boiler 锅炉 41.capsize 倾复 20.measurement(吨位)丈量，测量 42.stress 应力 21.trial 试航，试验 43.unequal distribution 分布不相等 44.longitudinal plane 纵向平面 45.hull girder 船体梁

AdditionalTerms and Expressions

1.tentative design 方案设计 2.preliminary design 初步设计 3.technical design 技术设计 4.working design 施工设计 5.basic design 基本设计

6.conceptual design 概念设计 7.inquire design 咨询设计 8.contract design 合同设计 9.detailed design 详细设计 10.finished plan 完工图

11.hull specification 船体说明书 12.general specification 全船说明书 13.steel weight 钢料重量

14.outfit weight（木作）舾装重量 15.machinery weight 机械重量 16.weight curve重量曲线

17.weight estimation 重量估计

18.cargo capacity 货舱容积

19.bale cargo capacity 包装舱容积 20.bulk cargo capacity 散装货容积 21.bunker capacity 燃料舱容积 22.capacity curve 容积曲线 23.capacity plan 容量（积）图 24.stowage factor 积载系数

25.homogenuous cargo 均质货物 26.gross tonnage 总吨位 27.net tonnage 净吨位

28.tonnage capacity 量吨容积 29.tonnage certificate 吨位证书

30.displacement length ratio 排水量长度比 31.accommodation 居住舱室 32.ice strengthening 冰区加强 33.drawing office 制图室 34.drafting room 制图室

Notes to the Text 1.A ship floats because as it sinks into the water it displace an equal weight of water, and pressure of the water produces an upward force which is called buoyancy.这是一个复合句。

从because开始至句末均属原因状语从句，它本身也是一个复合句，包含有以下从句：

as it sinks into the water 为整个原因状语从句中的时间状语从句;

it displaces an equal weight of water, and pressure of the water produces an upward 为整个原因状语从句中的两个并列的主要句子；

which is called buoyancy 为定语从句，修饰an upward force.2.In addition to 除……以外（还包括……）

例：In addition to these general requirements, … 除了这些一般要求外，还有……

而在The load which the ship carries in addition to its own weight is called the deadweight中的in addition to 应理解成“外加在它本身重量上的”，故应译为“本身重量除外（不包括本身重量）。

3.插入语，相当于 for example.一般在口语中用得比较多。

4.注意 ―ton‖, ―tonne‖, 和 ―tonnage‖ 三个词的区别。ton和tonne一般用来表示船舶的排水量和载重量，指重量单位。其中ton可分long ton(英吨)和 short ton(美吨)，而tonne为公吨；tonnage 是登记吨，表征船舶容积的一种单位。

5． …the angle of inclination at which the ship would capsize if it were inclined beyond that angle.从at 开始至句末是一定语从句，修饰angle, 而该从句本身又由一个带虚拟语气的主从复合句所构成。因为假设的条件不会发生，或发生的可能性非常小，所以主句和从句中的谓语动词都采用虚拟语气。

Lesson Five

General Arrangement

1.1 Definition The general arrangement of a ship can be defined as the assignment of spaces for all the required functions and equipment, properly coordinated for location and access.Four consecutive steps characterize general arrangement;namely, allocation of main spaces, setting individual space boundaries, choosing and locating equipment and furnishing within boundaries, and providing interrelated access.These steps progress from overall to detail considerations, although there is some overlapping.Generally, particular arrangement plans are prepared for conceptual, preliminary, contract, and working plan stages.The data for early stages come into first experience, and the degree of detail increases as the design progresses.It has often been said that ship design is inevitably a compromise between various conflicting requirements, and it is in formulation of the general arrangement that most of the compromises are made.Ship design requires a melding of many arts and sciences, and most of this melding occurs in the general arrangement.The designer considers the demands for all the functions and subfunctions of the ship, balances the relative types and importance of the demands, and attempts to arrive at an optimum coordinate relationship of the space assignments within the ship hull.The general arrangement, then, represents a summary or integration of information from other divisions and specialties in the ship design, to provide all the necessary functions of the ship in the most efficient and economical way from an overall viewpoint.The efficient operation of a ship depends upon the proper arrangement of each separate space and the most effective interrelationships between all spaces.It is important that the general arrangement be functionally and economically developed with respect to factors that affect both the construction and operation cost, especially the manpower required to operate the ship.Many other divisions of ship design provide the feed-in for the general arrangement, such as structure, hull engineering(hatch covers, cargo handling, etc), scientific(weights, stability, and lines), engineering(machinery, uptakes), and specifications.1.2 Function of ship

In this chapter, consideration of ship type is restricted to those whose function is to transport something for economic profit;in other words, commercial transportation.Such ship types may be subdivided in accordance with material to be transported;e.g., general cargo, bulk cargo, vehicles, passengers, etc.General cargo ships may further be subdivided in accordance with the form in which the general cargo is transported;e.g.break-bulk, containers, standardized pallets, roll-on/roll-off, etc.Bulk cargo ships may be subdivided into liquid bulk types and solid bulk types, or combinations of these, and, of course, may be further subdivided for specific liquids and solid bulks.Vehicle ships would include ferryboats and ships for the transoceanic delivery of automobiles, trucks, etc.Passengers can be carried in ships designed primarily for that purpose, as well as in any of the aforementioned types.Therefore, even after ship types are limited to those for Commercial transportation, they can have widely diverse functions.However, the common objective of the general arrangement in each case is to fulfill the function of the ship n the most economical manner;in other words develop a ship which will transport cargo at the least unit cost.This dual aspect of function cost is actually the force which has give rise to special ship types, many of which have been created in the last few years.The reason for this may be seen in a comparative annual cost break-bulk cargo ship fleet and a container ship fleet designed to carry the same cargo ,as estimated in ref[1].Conventional

Break-bulk

container

Fleer

Ship Fleet Capital……………………………………………………………..$2,370,000….$ 2,940,000 Operating…………………………………………………………….4,550,000

3,550,000 Cargo handing………………………………………………………22,900,000

4,920,000 Terminal allocation………………………………………………….1200,000

1,200,000 Overhead and allocations……………………………………………2,20,000

2200000 Total transportation cost …………………………………………….$33,220,000 $14,810,000 Cost per long ton of cargo transported………………………………$4,920

$2,190 It is the implication of such cost figures that gave rise to a rapid growth in the container ship type.Some such similar sets of cost figures, comparing different ways to accomplish the same function, explain the growth of any special ship type.The problems of general arrangement, then, are, associated with the function of the ship and generally fifer according to ship type.The arrangements of all types, however, have certain things in common.For example, the problems of accommodation and propulsion machinery arrangements are generally similar, although the different ship types impose different limitations.1.3

Ship as a system.In analyzing any tool or implement which has a functional-economic aspect, it is convenient to consider that tool as a system made up of a group of subsystems.By this approach, each subsystem may be analyzed separately, and its components and characteristics selected for optimum function and economics;then the subsystems may be combined to form the compatible system.Of course the subsystems must be compatible and the sum of their functions must equal the complete system function, just as the sum of their cists must equal the complete system costs.A ship which is a structural-mechanical tool or implement may be considered as a system for the transportation of goods or people ,across a body of water, from one marine terminal to another.The complete system is broken down into subsystems which generally must include, as a minimum, subsystems for:

 Enclosing volume for containing cargo and other contents of ship and providing buoyancy to support cargo and other weights(hull envelope). Providing structure for maintaining watertight integrity of enclosed volume and supporting cargo and other contents of ship against static and dynamic forces and primary strength of the hull girder(structure). Transporting cargo from pier to ship and stowing it aboard ship(cargo handling and stowage). Propelling ship at various speeds(machinery and control). Controlling direction of ship(steering). Housing and supporting human components of system(accommodations).Providing safety in event of accident(watertight subdivision, fire control, etc.).The general arrangement is largely developed by consideration of the requirement of each system, which are balanced, weighed, and combined into a complete system.However, the development of the general arrangement is not completely compatible with the system approach, because a general arrangement is a diagram of space and location, which may be minor aspects of certain subsystems.For example, some sub-subsystems occupy practically no space and do not appear on a general arrangement plan.Although this chapter will not go further with the system approach than is warranted by the subject of “general arrangement‖, it should be noted that each of the foregoing subsystems may be further broken down into second-degree subsystems(or sub-subsystems)and these in turn may be further broken down.The complete ship itself is, of course, a subsystem of larger system for the transportation of goods or people from any point on earth to any other point.1.4 The Problem and the approach

The first step in solving the general arrangement problem is locating the main spaces and their boundaries within the ship hull and superstructure.They are:

Cargo spaces

Machinery spaces

Crew, passenger, and associated spaces

Tanks

Miscellaneous

At the same time, certain requirements must be met, mainly:

Watertight subdivision and integrity

Adequate stability

Structural integrity

Adequate provision for access

As stated in the foregoing, the general arrangement is evolved by a gradual progress of trial, check and improvement.As for any other problem, the first approach to a solution to the general arrangement must be based on a minimum amount of information, including:  Required volume of cargo spaces, based on type and amount of cargo. Method of stowing cargo and cargo handling system. Required volume of machinery spaces, based on type of machinery and ship. Required volume of tankage, mainly fuel and clean ballast, based on type of fuel, and cruising range. Required standard of subdivision and limitation of main transverse bulkhead spacing. Approximate principal dimensions(length, beam, depth, and draft). Preliminary lines plan.The approximate dimensions and lines plan are base on a preliminary summation of the required volumes for all the aforementioned contents of the ship, a preliminary, estimate of all the weights in the ship, a selection of the proper hull coefficients for speed and power, and adequate freeboard and margin line for subdivision and stability.From the lines plan and margin line, a curve of sectional areas along the length of the ship and a floodable length curve may be made.The first general arrangement layout to allocate the main spaces is based on the foregoing information.Peak oulkheads and inner bottom are established in accordance with regulatory body requirements.Other main transverse bulkheads are located to satisfy subdivision requirements, based on preliminary floodable length curves.Decks are located to suit the requirements.Allowance for space occupied by structure must be deducted in arriving at the resulting net usable volumes and the clear deck heights.Usually, in the first approach, several preliminary general arrangements are laid out in the form of main space allocations, boundaries, and subdivisions.These are checked for adequacy of volumes, weights and stability, and the changes to be made in the preliminary lines to make these features satisfactory.At this point, certain arrangements may be dropped, either because they are not feasible or are less efficient than other arrangements.The general arrangement process then continues into more refined stages ,simultaneously with the development of structure, machinery layout, and calculations of weights, volumes, floodable length, and stability（intact and damaged）.The selection of one basic arrangement may cone early in the process, or may have to be delayed and based on a detailed comparison of ―trade-offs.‖ In any case, the selection is usually made in consultation with the owner so that consideration may be given to his more detailed knowledge of operating problems.（From “Ship Design and Construction” by D‘ Arcangelo, 1969）

Technical Terms

1.general arrangement 总布置 29.profit 利益 2.assignment 指定，分配 30.annual cost 费用 3.space 处所，空间 31.breakdown 细目 4.access 通道，入口

32.terminal allocation 码头配置费 5.allocation 分配，配置 33.overhead 管理费，杂项开支 6.furnishings 家具 34.component(组成)部分，分量 7.conceptual(design)概念（设计）35.characteristic 特性 8.preliminary(design)初步（设计）36.mechanical 机械的 9.contract(stage)合同（阶段）37.goods 货物 10.working plan 施工图 38.marine terminal 港口，码头 11.formulation 公式化，明确表达 39.enclosing volume 密（围）闭容积 12.melding 融合 40.hull envelope 船体外壳 13.optimum 最佳 41.primary strength 总强度 14.coordinate relationship 协调关系

42.stowage 配载 15.summary 综合，摘要 43.housing 容纳 16.integration 综合，积分 44.diagram 图 17.division 部分，划分 45.superstructure 上层建筑 18.efficient and economical way 有效和46.machinery space 机舱

经济的方式 47.miscellaneous(其他)杂用舱室 19.speciality 专业 48.watertight subdivision 水密分舱 20.feed-in 送进，提供 49.integrity 完整性 21.specifications 各种技术条件，说明书 50.tankage 液舱，容量（积）22.uptake 烟道 51.clean ballast 清洁压载 23.commercial transportation 商业运输 52.lines plan 型线图 24.solid(liquid)bulk type 固体（液体）53.crusing range 巡航范围

散装型 54.margine line 限界线 25.ferryboat 渡船 55.floodable length curve 可浸长度曲线 26.transoceanic 渡（远）洋的 56.layout（设计，布置）草图 27.automobile汽车 57.peak bulkhead 尖舱舱壁 28.aforementioned(a.m.)上述的 58.regulatory body 主管机构（关）59.intact stability 完整稳性 60.trade-off 权衡，折衷

61.consultation 协商

Additional Terms and Expressions

1.interior arrangement 舱室布置

2.stairway and passageway arrangement 梯道及走道布置

3.interior/exterior passageway 内/外走道 4.bridge deck 驾驶甲板 5.compass deck 罗经甲板 6.boat deck 艇甲板

7.promenda deck 游步甲板

8.accommodation deck 起居甲板 9.vehicle deck 车辆甲板

10.winch platform 起货机平台 11.wheel house 驾驶室 12.chart room 海图室 13.radio room 报务室 14.electric room 置电室 15.mast room 桅室

16.caption‘s room 船长室 17.crew‘s room 船员室 18.cabin 客舱

19.main engine control room 主机操纵室 20.auxiliary engine room 副机舱

21.boiler room 锅炉间

22.steering engine room 舵机舱 23.workshop 机修间 24.store 贮藏室

25.fore/aft peak 首/尾尖舱

26.topside/bottomside tank 顶边/底边舱 27.wing tank 边舱

28.steering gear 操舵装置

29.anchor and mooring arrangement 锚泊和

系缆设备

30.howse pipe 锚链筒 31.chain locker 锚链舱

32.closing appliances 关闭设备 33.hatch cover 舱口盖

34.lifesaving equipment/appliance 救生设备 35.mast 桅 36.rigging 索

37.bollard 双柱带缆柱 38.bitt 带缆桩 39.fairlead 导缆钩

Notes to the Text

1.It is in formulation of the general arrangement that most of the compromises are made.这是“it is … that … ”强调句型，强调in formulation of the general arrangement.in formulation of 原意为“在……的表达中”，现意译为“体现在……中”。

2.It is important that the general arrangement be functionally and economically developed…

这是虚拟语气形式的句型，在that 从句中采用原形动词。类似的句型还有：

It is desired/suggested/requested that……

It is necessary that …

有时It is essential that …也用虚拟语气。3.hull engineering 为“船舶设备”之意 4.scientific 原意为“科学的”，现根据上下文意译成“船舶性能”。5.at the least unit cost 以最小的单价 6.a long ton 一英吨（=2240磅）

a short ton 一美吨（=2000磅）

7.any tool or implement 在这里implement 和tool 基本上同义，帮or 后面的名词在翻译时可以省略不译。

8.across a body of water 穿过一段水路/一个水域

9.aboard ship和 on board ship, 以及on board a(the ship)都为“在船上”之意。

10.Although this chapter will not go further with the system approach than is warranted by the subject of ―general arrangement‖.这个让步状语从句中包含有比较状语从句。than 后面的主语（this chapter）被省略掉了。其中的is warranted 原意为“补认为是合理（或正当）的”，整个从句可翻译成：“虽然这一章只限于‘总布置’这个主题，而不再进一步讨论系统处理方法”。

Lesson Six

Ship Lines The outside surface of a ship is the surface of a solid with curvature in two directions.The curves which express this surface are not in general given by mathematical expressions, although attempts have been made from time to time to express the surface mathematically.It is necessary to have some drawing which will depict in as detailed a manner as possible the outside surface of the ship.The plan which defines the ship form is known as a ‘line plan‘.The lines plan consists of three drawings which show three sets of sections through the form obtained by the intersection of three sets of mutually orthogonal planes with the outside surface.Consider first a set of planes perpendicular to the centre line of the ship.Imagine that these planes intersect the ship form at a number of different positions in the length.The sections obtained in this way are called ‗body section‘ and are drawn in what is called the ‗body sections‘ as shown in Figure 1*.When drawing the body plan half-sections aft of amidships（the after body sections）are drawn on one side of the centre line and the sections forward of amidships(the fore body sections)are drawn on the other side of the center line.It is normal to divide the length between perpendiculars into a number of divisions of equal length(often ten)and to draw a section at each of these divisions.Additional sections are sometimes drawn near the ends where the changes in the form become more rapid.In merchant ship practice the sections are numbered from the after perpendicular to the forward perpendicular —thus a.p.is 0 and f.p.is 10 if there are ten divisions.The two divisions of length at the ends of the ship would usually be subdivided so that there would be sections numbered 1/2, 11/2, 81/2, and 91/2.Sometimes as many as 20 divisions of length are used, with possibly the two divisions at each end subdivided, but usually ten divisions are enough to portray the form with sufficient accuracy.Suppose now that a series of planes parallel to the base and at different distances above it are considered.The sections obtained by the intersections of these planes with the surface of the ship are called ‗waterlines‘ or sometimes ‗level lines‘.The lines are shown in Figure 1.The waterlines like the body sections are drawn for one side of the ship only.They are usually spaced about, 1m(3-4ft)apart, but a closer spacing is adopted near the bottom of the ship where the form is changing rapidly.Also included on the half breadth plan is the outline of the uppermost deck of the ship.A third set of sections can be obtained by considering the inter-section of a series of vertical planes parallel to the centre line of the ship with the outside surface.The resulting sections are shown in a view called the ‗sheer profile‘ see Figure 1 and are called ‗buttocks‘ in the after body and ‗bow lines‘ in the fore body or often simply ‗buttocks‘.The buttocks like the waterlines will be spaced 1m(3-4ft)apart.On the sheer profile the outline of the ship on the centre line is shown and this can be regarded as a buttock at zero distance from the centre line.The three sets of sections discussed above are obviously not independent of one another, in the sense that an alteration in one will affect the other two.Thus, if the shape of a body section is altered this will affect the shape of both the waterlines and the buttocks.It is essential when designing the form of the ship that the three sets of curves should be ‗fair‘ and their interdependence becomes important in this fairing process.What constitutes a fair curve is open to question.But formerly the fairing process was done very largely by eye.Nowadays the lines plan is often faired by some mathematical means which will almost certainly involve the use of the computer.However the fairing process is carried out the design of the lines of a ship will normally start by the development of an approximate body plan.The designer when he has such a body plan will then lift offsets for the waterlines and will run the waterlines in the half-breadth plan.This means drawing the best possible curves through the offsets which have been lifted from the sections, and this is done by means of wooden or plastics battens.If it is not possible to run the waterlines through all the points lifted from the body plan then new offsets are lifted from the waterlines and new body sections drawn.The process is then repeated until good agreement is obtained between waterlines and body sections.It is then possible to run the buttocks, and to ensure that these are fair curves it may be necessary to adjust the shape of body sections and waterlines.The process of fairing is usually done in the drawing office on a scale drawing.It is clear that a much more accurate fairing of the form is necessary for production purposes in particular, and this used to be done in the mould loft of the shipyard full size.The procedure was for the drawing office to send to the mould loft office from the lines as faired in the office and they were laid out full size on the loft floor.A contracted scale was adopted for the length dimension but waterline and section breadths and buttock heights were marked out full size.The same process of fairing was then adopted as used in the office, the fairing being done by using wood battens of about 25mm square section pinned to the loft floor by steel pins.To save space the waterlines and buttocks in the forward and after bodies were overlapped in the forward and after bodies were overlapped in the length direction.This type of full scale fairing enabled sections, waterlines and buttocks to be produced which represented the desired form with considerable accuracy.From the full scale fairing, offsets were lifted which were returned to the drawing office and made the basis of all subsequent calculations for the ship, as will be seen later.A more recent development has been the introduction of 1/10 scale lofting, which can be done in the drawing office, and the tendency has been to dispense with full scale loft work.Several methods have also been developed for the mathematical fairing of ship forms and linking this up with production processes.Discussion of these topics, however, is outside the scope of this work..The lines drawn on the lines plan representing the ship form are what are called ―moulded lines‖, which may be taken to represent the inside of the plating of the structure.The outside surface of the ship extends beyond the moulded lines by one thickness of shell plating in an all welded ship.When riveting was put on in a series of ―in‖ and ―out‖ strakes.In this case the outsides surface of the ship extended two thicknesses of plating beyond the moulded lines in way of an outside strake and one thickness beyond the moulded lines in way of an inside strake.Actually the outside surface would be rather more than one thickness or two thicknesses of plating, as the case may be beyond the moulded line in places where there is considerable curvature of the structure, as for example at the ends of the ship or below the level of the bilge.In multiple screw merchant ships it is customary to enclose the wing shafts in what is called a ―shaft bossing‖.This consists of plating, stiffened by frames and extending from the point where the shafts emerge from the ship and ending in a casting called a ―shaft bracket‖.The bossing is usually faired separately and added on to the main hull form.The bossing is treated as an appendage.In many ships of the cross section does not change for an appreciable distance on either side of amidships.This portion is called the ―parallel middle body‖ and may be of considerable extent in full slow ships but may not exist at all in fine fast ships.Forward of the parallel middle the form gradually reduces in section towards the bow and in like manner the form reduces in section abaft the after end of the parallel middle.These parts of the form are called respectively the ―entrance‖ and the ―run‖ and the points where they join up with the parallel middle are referred to as the ―forward‖ and ―after shoulders‖.(From ―Naval Architecture for Marine Engineering‖ by W.Muckle, 1975)

Technical terms

1.ship lines 船体线型 21.drawing office 制图/设计室 2.ship form 船体形状 22.mould loft 放样间 3.mathematical expressions 数学表达式 23.full size 实尺（1：1）4.drawing 图，拉延 24.loft floor 放样台 5.lines plan 型线图 25.contracted scale 缩尺 6.orthogonal plan 正交平面 26.lofting 放样 7.body section 横剖面 27.steel pin 铁钉 8.body plan 横剖线图 28.mathematical fairing of ship form 船体9.symmetry 对称 数学光顺法 10.water lines /level lines 水线，水平型线 29.screw 螺旋桨，螺钉 11.half breadth plan 半宽水线图 30.wing shaft 侧轴 12.view 视图，观察 31.shaft bossing 轴包套 13.sheer profile 侧视图，纵剖线图 32.casting 铸件 14.buttocks 后体纵剖线 33.shaft bracket 轴支架 15.bow line 前体纵剖线 34.appendage 附属体 16.after/fore body 后/前体 35.parallel middle body平行中体 17.alteration 修改，变更 36.full slow ship 丰满的低速船 18.fairing process 光顺过程 37.fine fast ship 尖瘦的快速船 19.offsets 型值 38.entrance 进流端入口

to lift offsets 量取型值 39.run 去流端，运行，流向 20．Wooden/plastics battern 木质/塑料压条 40.forward/after shoulder 前/后肩

Additional Terms and Expressions

1.grid 格子线 4.station ordinate 站线 2.ordinate station 站 5.finished/returned offsets 完工型值 3.midstation 中站 6.table of offsets 型值表 7.diagonal 斜剖线 11.preliminary offsets 原始型值 8.keel line 龙骨线 12.mathematical lines 数学型线 9.rake of keel, designed drag 龙骨设计斜13.mathematical fairing of lines 型线数学光度 顺法 10.knuckle line 折角线

Notes to the Text

1.in as detailed a manner as possible 相当于 in a manner as detailed as possible, 阅读和翻译科技原文时，应注意这类不一般的语序。

2.关系词what可引出主语从句，表语从句等。例如：…in what is called the ‘body plan’及…in what is called a ‘shaft bossing’中的what从句作为介词in的宾语从句。

What constitutes a fair curve is open to question…中的what从句为主语从句。

The lines drawn on… are what are called moulded lines 中的what 从句为表语从句。3.When drawing the body plan half-sections only are shown because of the symmetry of the ship.When drawing the body plan 是省略了主语和谓语一部分（to be）的时间装语从句，尽管从句和主句的主语并不一致。这种省略方法似乎与一般的英语语法规律有矛盾，但在科技文献中较常见，其原因是这类省略不会引起读音的误解。

4.a.p.和f.p.分别为after perpendicular(尾垂线)和forward perpendicular(首垂线)的缩写。5.Also included on the half-breadth plan is the outlines of the uppermost deck of the ship.这是依据倒装句，为了突出情调部分，此句中的also included on the half breadth plan 这部分移至句首，主语the outline of…反而置于句末。

6.on a scale of 1/4 in to 1 ft or on 1/50 scale 以一个1/4英寸代表1英尺的比例尺（即1：48）或1:50的比例尺。

7.The procedure was for the drawing office to the mould loft offsets from the lines as faired in the office and they were laid out full size on the loft floor.for the drawing office to send….是‖for+名词+不定式‖结构，在句中作表语。For后面的the drawing office 可看作不定式的逻辑主语。

Offsets 是不定式to send 的宾语。由于它后面有一个较长的介词短语from the line(其后面又有as faired in ….On the loft floor 修饰the line)加以修饰，为了句子结构平衡的需要，被移至介语短语to the mould loft(作为地点状语用)之后。8.in way of….在…部位，在….处

这一组合介词在造船和海洋工程英语中用得较普遍。例：The structural strength of a ship in way of the engine and boiler space demands special attention the designer.机炉舱部位的船体轻度要求设计人员给予特别的注意。

The thickness of upper shell plating should be increased in way of the break.船楼端部处的上层壳板厚度应该增加。/ 9.as the case may be 按情况而定。

Lesson Seven

Ship Equilibrium, Stability and Trim

The basis for ship equilibrium

Consider a ship floating upright on the surface of motionless water.In order to be at rest or in equilibrium, there must be no unbalanced forces or moments acting on it.There are two forces that maintain this equilibrium(1)the force of gravity, and(2)the force of buoyancy.When the ship is at rest, these two forces are acting in the same perpendicular line, and , in order for the ship to float in equilibrium, they must be exactly equal numerically as well as opposite in direction.The force of gravity acts at a point or center where all of the weights of the ship may be said to be concentrated: i.e.the center of gravity.Gravity always acts vertically downward.The force of buoyancy acts through the center of buoyancy, where the resultant, of all of the buoyant forces is considered to be acting.This force always acts vertically upward.When the ship is heeled, the shape of the underwater body is changed, thus moving the position of the center of buoyancy.Now, when the ship is heeled by an external inclining force and the center of buoyancy has been moved from the centerline plane of the ship, there will usually be a separation between the lines of action of the force of gravity and the force of buoyancy.This separation of the lines of action of the two equal forces, which act in opposite directions, forms a couple whose magnitude is equal to the product of one of these forces(i.e.displacement)and the distance separating them.In figure 1(a),where this moment tends to restore the ship to the upright position, the moment is called the righting moment, and the perpendicular distance between the two lines of action is the righting arm(GZ).Suppose now that the center of gravity is moved upward to such a position that when the ship is heeled slightly, the buoyant force acts in a line through the center of gravity.In the new position, there are no unbalanced forces, or, in other words, a zero moment arm and a zero moment.In figure 1(b),the ship is in neutral equilibrium, and further inclination would eventually bring about a change of the state of equilibrium.If we move the center of gravity still higher, as in figure 1(c),the separation between the lines of action of the two forces as the ship is inclined slightly is in the opposite direction from that of figure 1(a).In this case, the moment does not act in the direction that will restore the ship to the upright but will cause it to incline further.In such a situation, the ship has a negative righting moment or an upsetting moment.The arm is an upsetting arm, or negative righting arm(GZ).These three cases illustrate the forces and relative position of their lines of action in the three fundamental states of equilibrium.32

Fig.1 Stable(a), Neutral(b), and Unstable(c)

Equilibrium in the upright position

The hull is shown inclined by an outside force to demonstrate the tendency in each case(From ―Modern Ship Design ‖ Second Edition, by Thomas.C.Gillmer, 1975)Stability and trim

Figure 2 shows a transverse section of a ship floating at a waterline WL displaced from its

buoyancy

Weight of ship

Fig.2 Stability shown in a transverse section of a floating ship(see text)

original waterline WL.One condition of equilibrium has been defined above.A second condition is that the centre of gravity of a ship must be in such a position that, if the vessel is inclined, the forces of weight and buoyancy tend to restore the vessel to its former position of rest.At small angles, vertical lines through B, the centre of buoyancy when the vessel is inclined to an angle 0,intersect the center line at M, the metacentre, which means ―change

point‖.If M is above G(the centre of gravity of the ship and its contents),the vessel is in stable equilibrium, When M concides with G, there is neutral equilibrium.When M is below G, the forces of weight and buoyancy tend to increase the angle of inclination, and the equilibrium is unstable.The distance GM is termed the metacentric height and the distance GZ, measured from G perpendicular to the vertical through B, is termed the righting level or GZ value.Weight and buoyancy are equal and act through G and B, respectively, to produce a moment(tendency to produce a heeling motion)△GZ, where △ is the displacement or weight in tons.Stability at small angles, known as initial stability, depends upon the metacentric height GM.At large angle, the value of GZ affords a direct measure of stability, and it is common practice to prepare cross-curves of stability, from which a curve of GZ can be obtained for any particular draft and displacement.Transverse stability should be adequate to cover possible losses in stability that may arise from flooding, partially filled tanks, and the upward thrust of the ground or from the keelblocks when the vessel touches the bottom on being dry-docked.The case of longitudinal stability, or trim, is illustrated in Figure3.There is a direct analogy with the case of transverse stability.When a weight originally on board at position A is moved a distance d, to position B, the new waterline W1L1 intersects the original waterline WL at center of flotation(the centre of gravity of the water plane area WL),the new centre of buoyancy is B, and the new centre of gravity is G.For a small angle of trim, signified by the Greek letter theta(θ)，θ=(a+f)/L wd=△GMl(a+f)/L

Changes in stern trim is x-y

Fig.3 Longitudinal section of float ship showing change in stern trim as deck load w was shifted

from position A to position B(see text)

Thus if（a+f）=1 inch =1/12 foot, wd =△GM/12L and this presents the moment to change trim one inch.The inclining experiment

A simple test called the inkling experiment provides a direct method of determining GM, the metacentric height, in any particular condition of loading, from which the designer can deduce the position of G, the ship‘s centre of gravity.If a weight w(ton)is transferred a distance d(feet)from one side of the ship to the other and thereby causes an angle of heel theta(θ)degrees，34 measured by means of a pendulum or otherwise, then GM=wd/△tanθ(see Figure 2).For any particular condition, KB and BM can be calculated, GM is found by the inclining experiment, whence KG=KM-GM.It is simple to calculate the position of G for any other condition of loading.(From ―Encyclopedia Britannica‖, Vo1.16, 1980)

Technical Terms

1.equilibrium平衡 15.stable equilibrium 稳定平衡 2.stability and trim 稳性与纵倾 16.netural equilibrium 中性平衡 3.floating upright 正浮 17.metacenter height 稳心高 4.force of gravity 重力 18.righting level 复原力臂 5.resultant 合力 19.initial stability 初稳性 6.center of buoyancy 浮力 20.cross-curves of stability 稳性横截曲线 7.couple 力偶 21.flooding 进水 8.magnitude 数值（大小）22.thrust 推力 9.displacement 排水量，位移，置换 23.keelblock 龙骨墩 10.righting moment 复原力矩 24.dry dock 干船坞 11.righting arm 复原力臂 25.center of floatation 漂心 12.upsetting moment 倾复力矩 26.Greek letter 希腊字母 13.upsetting arm 倾复力臂 27.inclining experiment 倾斜试验 14.metacentre 稳心 28.pendulum 铅锤，摆

Additional Terms and Expressions

1.lost buoyancy 损失浮力 9.stability at large angles 大倾角稳性 2.reserve buoyancy 储备浮力 10.dynamical stability 动稳性 3.locus of centers of buoyancy 浮心轨迹 11.damaged stability 破舱稳性 4.Bonjean‘s curves 邦戎曲线 12.stability criterion numeral 稳性衡准书 5.Vlasov‘s curves 符拉索夫曲线 13.lever of form stability 形状稳性臂 6.Firsov‘s diagram 菲尔索夫图谱 14.locus of metacenters 稳心曲线 7.Simpson‘s rules 辛浦生法 15.angle of vanishing stability 稳性消失角 8.trapezoidal rule 梯形法 16.free surface correction 自由液面修正

Notes to the Text

1.When the ship is at rest, these two forces are acting in same perpendicular line, and, in order for the ship to float in equilibrium, they must be exactly equal numerically as well as opposite in direction.in order for the ship to float in equilibrium 是“in order带to的不定式“结构，表示目的状语，其中for the ship中的the ship是不定式逻辑主语。

As well as是一个词组，可有几种译法，具体译成什么意思应根据上下文加以适当选择。例如：

The captain as well as the passenger was frightened.船长和旅客一样受惊。（和……一样）受惊的既有旅客又有船长。（既……又）

不仅旅客而且船长也受惊了。（不仅……而且）除旅客外，还有船长也受惊了。（除……外，还）

不管那种译法，强调的都是as well as前面的那个名次（例句中的the captain,船长），因此谓语动词的性、数也由这个名词决定。

2.thus moving the position of the center of buoyancy.由thus引出的现在分词短语用作表示结果的状语。一般来说，如分词短语位于句末，往往有结果、目的等含义。

3.suppose now that the center of gravity is moved upward to such a position that when the ship is heeled slightly, the buoyant force acts in a line through the center of gravity.Suppose now that …与now let‘s suppose that…同意，其后that 所引出的从句是suppose 的宾语从句。

to such a position that…是such…that…引导结果状语从句。但在这个从句中又包含了一个由关系副词when引导的时间状语从句。

4.Figure 2 shows a transverse section of a ship floating at a waterline WL, displaced from its original waterline WL.floating at a waterline WL 现在分词短语（含有主动态），修饰前面的名词a ship;displaced from its original waterline WL 过去分词短语（含有被动态），也是修饰前面的名词，ship,注意这里的displaced 应选择“移动位置”的词义。

5.At small angles, vertical lines through B, the center of buoyancy when the vessel is inclined at an angle θ，intersect the center line at M, the metacenter, which means ―change point‖.此句的主要成分为vertical lines intersect the center line.the center of buoyancy 是B的同位语。the metacenter 是M的同位语。

6.Tranverse stability should be adequate to cover possible losses in stability that may arise from flooding ,partically filled tanks, and the upwards thrust of the ground or from the keelblocks when the vessel touches the bottom on being dry-docked.that may arised from…the keelblocks是定语从句，修饰losses.when the vessel…on being dry-docked是时间状语从句，修饰may arise from the keelblock.on being dry-docked 中的being dry-docked是动名词的被动态，接在on之后表示（刚）进船坞的时候。

7.or otherwise意为“或相反，或其他”。例：

It can be verified by trial or otherwise.这可用试验或其他方法加以验证。

Fine or otherwise,we shall have to do this test.不管天气好不好，我们非做这个试验不可。

Lesson Eight

Estimating Power Requirements The power required to propel a new ship is subject to a formidable number of variable items.The family tree of power for propulsion(Fig.1)shows these divided into two main groups.One is concerned with the resistance to motion caused by the interaction of the hull of the ship with the surrounding water and the other concerns the efficiency with which the power developed in the engine itself can be used and converted into thrust at the propeller.Before considering the methods used for estimating their combined effect on power requirements, it is necessary to take the items in turn and discuss briefly their significance and nature.Fig.1 Power for propulsion

Ship resistance Friction at the hull surface in contact with the water is the major part of the resistance of all merchant vessels.Wave-making resistance does not assume prime importance until a speed/length ratio(V/√L)in excess of unity has been reached.The reason for surface friction is that water is far from being a perfect fluid.Its magnitude depends on the length and area of surface in contact and its degree of roughness, and it varies with the speed of the body through the fluid.By observation and experiment it can be shown that the particles of water in actual contact with the ship adhere to its surface and are carried along by it(it does not seem unreasonable to assume some interlocking of particles).There is no slip.At small distances from the body the velocity imparted to the surrounding fluid is only very small but with a noticeable degree of turbulence.The width of this belt, known as the layer increases somewhat towards the after end of the moving body.Its appearance is one of the most spectacular sights to be seen when a vessel is moving at high speed.from a practical point of view it is assumed that all the fluid shear responsible for skin friction occurs within this belt and also that outside it fluid viscosity can be disregarded.The exact width of the belt is difficult to determine, but an arbitrary assessment is usually accurate enough.If it is now considered that the effective shape of the immersed body is defined by the extremities of the boundary layer, then that body may be assumed to move without friction.However, this does not apply to the transmission of pressure.Part of the energy necessary to move a ship over the surface of the sea is expended in the form of pressure waves.This form of resistance to motion is known as residual resistance, or wave-making.Three such wave systems are created by the passage of a ship: a bow system, a stern system(both of which are divergent), and a transverse system.They occur only in the case of a body moving through two fluids simultaneously.For instance, the residuary resistance of well formed bodies like aircraft or submarines, wholly immersed, is comparatively small.Because of surface waves formed by a floating body the flow pattern varies considerably with speed, but

with an immersed body this flow pattern is the same at all speeds.For this reason the shape of a submarine or aircraft(in consideration of submerged performance only)is more easily related to the constant conditions under which it performs ,in the dynamic sense, than is the form of surface vessel.Returning to a consideration of our three wave systems, it can easily be understood that the bow system is initiated by a crest due to the build-up of pressure necessary to push the water aside and the greater the speed the greater will be the height of the crest and its distance from the bow.Conversely, the stern system is associated with a hollow due to filling-in at the stern.If a ship had a sufficient length of parallel middle body the bow wave system would die out before it reached the stern, but in practice ships are never long enough for this to obtain and interference effects have to be taken into account.The transverse wave system becomes of importance at high speeds and is responsible for the greater part of wave-making resistance.The net effect of the three systems is extremely important from a residuary resistance point of view, and it is necessary to ensure that they do not combine to produce a hollow(a through)at the stern.Of course, if the energy produced at the bow could be recovered at the stern then there would be no net energy loss.But this is not the case as energy is dissipated laterally in order to maintain a wave pattern.The more developed the wave pattern the more energy is needed to maintain it.Considerations of minimum resistance, therefore, involved a complicated assessment of the interrelation of ship-form characteristics likely to reduce wave causation.Wave-making resistance follows the laws of dynamic similarity(also known as Froude‘s Law of Comparison), which state that the resistances of geometrically ships will vary as the cube of their linear dimensions provided the speeds are in the ratio of the square root of the linear dimensions.Perhaps the law, which does not apply to frictional resistance, looks more concise if stated symbolically, namely:

RtL3V3providedrtvlL l

The most important cause of eddy-making is the ship.There is sometimes a tendency to think of eddy-making as being related only to such appendages as rudders, bilge keel, propeller bossings and the like.While it is perfectly true that badly designed appendages can have eddy-making resistances which are excessive in relation to their size and frictional resistances, the eddy-making of a ship, though relatively small, may be a very large part of the total eddy-making resistance.Eddy making is usually included with the wave-making resistance because it is impracticable to measure the one without the other.However, some distinction is helpful to an understanding of resistance phenomena.In eddy-making it is the stern of the ship which plays the influential part because of the difficulty of maintaining streamline flow even in the most easily shaped body.Propulsion

It will be obvious that the total resistance of a ship at any speed and the force necessary to propel it must be equal and opposite.The power that the ship‘s machinery is capable of developing, however, must be considerably more than this to overcome the various deficiencies inherent in the system, because engines, transmission arrangements and propellers all waste power before it becomes available as thrust.The total efficiency of propulsion therefore involves a consideration of the separate efficiencies of individual items the product of which is expressed in the form of a propulsive coefficient.The engine efficiency depends upon the type of engine employed and its loading.In the case of a reciprocating engine, either diesel or steam, the power developed in the cylinders can be calculated from the effective pressures recorded on indicator cards.This is known as indicated h.p., which is naturally more than the horsepower output when measured by means of a brake at the crankshaft coupling.The ratio b.h.p./i.b.p.is, of course the mechanical efficiency of the engine.If the power is measured on the propeller shaft aft of the thrust

block and any gearing, then this is known as shaft h.p.and in the case of a turbine is the only place at which it is practicable to measure the power output.There is no such thing as indicated or brake horsepower for a steam or gas turbine, shaft h.p.is almost the same as b.h.p.for a reciprocating engine which drives the propeller directly, but where gearing or special couplings are introduced in the case of high-speed diesel engines or turbines, the transmission losses in these items influence the s.h.p.This is, of course very necessary in order that fair comparisons between the efficiencies of different types of drives can be made.The remainder of the transmission losses are those in the stern tube.When all the engine and transmission losses have been taken into account what is left is a certain amount of the original power which is now delivered at the propeller.We have already noted that a ship in motion drags along with it a large mass of water.This ―wake‖ as it is known(not the popular interpretation of something that is left astern!)has a forward velocity in which the screw operates, so that the speed of the screw through the wake water is less than the speed of the ship.This is beneficial as it involves a gain in efficiency which is referred to as the wake gain.On the pressure distribution at the stern of the vessel which causes some augment of resistance.It is usual to consider this as a thrust deduction effect.These almost separate effects can be combined to give the effective horse-power required.The screw efficiency in the open, i.e.delivering its thrust to an imaginary vessel, is most important.It is only by considering hull resistance and propeller performance as separate entities that any proper assessment can be made of their effect when combined.The mechanism of hull resistance has been fairly well explored, but the theories of propeller action are still incomplete.Power estimates

When power estimates are required by a shipbuilder who is tendering for the construction of a new vessel, there is no time to run model tests, nor would the expense normally the justified.The naked e.h.p.is therefore estimated from a published series of methodical tests such as those of Ayre or Taylor.Percentage allowances are made to the naked e.h.p.for appendages and air resistance combined with an estimated lies in the proper selection of the QPC.There are numerous methods of estimating power, but the above is one of the most popular.Some rapid means of evaluating ship power requirements merely from a lines plan and main technical particulars has long been needed.With increasing productivity, faster construction times and fierce international competition for new orders this has become ever more pressing.Detailed power assessments for ship design proposals are needed frequently well in advance of any firm order.Statistical analysis methods are now being applied to resistance and propulsion problems to peed up the process of ship performance prediction.Performance criteria are expressed, in terms of equations based on selected parameters of hull shape, dimensions, propeller characteristics and stern conditions.Performance of a design can be assessed from these regression equations which have been derived from a large number of previous model results for the ship type under review.Comparison of a particular result with established data is obtained by minimization of the regression equations.The big advantage of doing things this way is that the coefficients of the regression equations can be fed into a high-speed digital computer.This means that in less than an hour the results of well over a dozen different combinations of hull characteristics can be calculated.This should then lead to an optimum combination of form parameters.The eventual link up with work now being done on the complete definition of hull shape in mathematical terms should take us one step nearer to the soundly based fully automated shipyard.(From ― Background to Ship Design and Shipbuilding Production‖ by J.Anthony Hind, 1965).39

Technical Terms

1.resistance 阻力 2.thrust 推力

3.propeller 推进器

4.skin friction resistance 摩擦阻力 5.wave-making resistance 兴波阻力 6.eddy-making resistance 漩涡阻力 7.appendage resistance 附体阻力 8.propulsive efficiency 推进效率 9.hull efficiency 船身效率

10.transmission efficiency 轴系效率 11.speed/length ratio 速长比 12.perfect fluid 理想流体 13.roughness 粗糙度 14.turbulence 紊动

15.boundary layer 边界层

16.spectacular sights 壮观景色 17.fluid shear 流体剪力 18.fluid viscosity 流体粘性

19.immersed body 浸没的船体部分 20.residuary resistance 剩余阻力 21.bow 船首 22.stern 船尾

23.divergent 分散的 24.submarine 潜水艇 25.aircraft 飞机 26.crest 波峰

27.hollow 凹陷，孔隙，波谷 28.parallel middle body平行中体 29.through 波谷

30.ship-form characteristics 船型特性

31.laws of dynamics similarity 动力相似定律 32.rudder 舵

33.bilge keel 舭龙骨

34.propeller bossing 推进器箍 35.streamline 流线型

36．reciprocating engine 往复式发动机 37.diesel/steam engine 柴油/蒸汽机 38.indicator card 示功图 39.indicated h.p.指示马达 40.brake 制动

41.crankshaft coupling 曲轴连轴器 42.mechanical efficiency 机械效率 43.thrust block 推力轴承 44.gearing 齿轮 45.shaft h.p.轴马达 46.brake h.p.制动马达 47.turbine 汽轮机

48.gas turbine 燃气轮机 49.stern tube 尾轴管 50.wake 伴流

51.astern 向（在）船尾 52.wake gain 伴流增益

53.thrust deduction 推力减额

54.effective horse-power(e.h.p.)有效马达

55.screw efficiency in the open(water)螺旋桨趟水效率

56.imaginary vessel 假想船

57.mechanism 作用原理（过程），机构 58.proposal 建议

59.statistical 统计分析 60.criterion 衡准

61.ship performance prediction 船舶性能预报 62.regression equation 回归方程 63.form parameter 形状参数

Additional Terms and Expression 1.2.3.4.5.6.7.service speed 服务航速 design speed 设计航速 cruising speed 巡航速度 trial speed 试航速度 endurance 续航力

admiralty coefficient/constant 海军系数 fouling 污底

8.hydrodynamics 水动力学 9.inflow 进流

10.angle of attack 攻角

11.lift 升力

12.circulation 环量

13.aspect ratio 展弦比

14.Reynolds number 雷诺数 15.Froude number 傅汝德数 16.momentum theory 动量理论 17.impulse theory 冲量理论 18.cavitation 空泡现象

19.adjustable-pitch propeller 可调螺距螺旋桨

controllable-pitch propeller 可调螺距螺旋桨 20.reversible propeller 可反转螺旋桨

21.coaxial contra-rotating propellers 对转螺旋桨 22.ducted propeller, shrouded propeller 导管螺旋桨 23.tandem propeller 串列螺旋桨

24.jet propeller 喷射推进器 25.paddle wheel 明轮

26.ship model experiment tank 船模试验水池 27.ship model towing tank 船模拖拽试验水池 28.wind tunnel 风洞

29.cavitation tunnel 空泡试验水筒 30.self propulsion test 自航试验 31.scale effect 尺度效应 32.naked model 裸体模型

1.2.3.4.5.6.Notes to the Text

the family tree of power for propulsion 推进马力族类表

For this reason the shape of a submarine or aircraft(in consideration of submerged performance only)is more easily related to the constant conditions under which it performs, in the dynamic sense, than is the form of a surface vessel.其中的主要句子the shape---is more easily---than---是一句带有比较状语从句的复合句。在than is the form of a surface vessel 中省略了 easily related to the variable conditions under which it performs,显然，to the constant conditions 和 to the variable conditions 实际上是不同的。严格说，这种省略方法是不正规的，但由于读者能从上下文联系中容易判断出种种不同，为了简便起见，作了省略。在英美科技文章中有此种现象。

the greater the speed the greater will be the height of the crest and its distance from the bow.The more developed the wave pattern the more energy is needed to maintain it.这两句都是“the+比较级---the +比较级”结构的句型。this is not the case 情况并非如此

and the like = and such like 以及诸如此类

The eventual link up with work now being done on the complete definition of hull shape in mathematical

Lesson Nine

Ship Motions, Manoeuvrability Ship motions Ship motions are defined by the movements from the equilibrium position of the ship‘s centre of gravity along the three axes shown in Figure 1 and by rotations about axes approximately parallel to these.The linear displacements along the horizontal(x), lateral(y), and veritical(z)

Fig.1 Coordinate axes of ship motions(see text)

axes are termed surge, sway, and heave, respectively.The rotations about the corresponding body axes are respectively termed roll, pitch, and yaw(veering off course).Roll, pitch, and heave are oscillatory because hydrodynamic forces and moments oppose them.Ship motions are important for many reasons.A ship should be able to survive any sea that may be Encountered and, in addition, to behave well and to respond to control.In brief, a ship should respond to the action of the sea in such a manner that the amplitudes of its motions and its position never become dangerous, and so that the accelerations it undergoes are kept within reasonable limits.Propulsive performance, or heaving.Hence these motions are made as small as possible.Ship motions are excited by waves, whose growth is governed by the wind velocity at the sea surface, the area of water, or distance, over which the wind blows(the ―fetch‖), and the length of time during which the wind has been blowing(the ―duration‖).Any seaway is always a complex mixture of waves of different lengths, as wind itself is a complex mixture of gusts.All wave components do not travel in the same direction, but the directions of most of them in a single storm lie within 30°of each other.Regular trains of waves of uniform height and length are rarely, if ever, encountered.Most seas are confused and can be considered as made up of many separate component waves that differ in height and length.Pitching, rolling, and heaving are all excited by the changing pattern of surface waves in relation to the speed and course of the ship.In practice, it is possible to damp one motion only---that of rolling.The fitting of bilge keels(finlike longitudinal projections along the part of the underwater body of a ship between the flat of the bottom and the vertical topsides)has this effect, and still more effective means are the activated for stabilizer(a device along the side of a ship activated by a gyroscope and used to keep the ship steady)and the passive or flume stabilizing tank, filled with water inside the ship.Manoeuvrability

Increases in the size and speed of ships bring problems of safe operation in congested waters and control at high speed in waves.Therefore, designs necessarily represent a compromise between manoeuvrability and course-keeping ability.Ship operators desire maximum manoeuvrability in port to minimize the need for assistance from tugs and to reduce delays in docking.They also desire a ship that can hold a steady course at sea with the minimum use of helm.These aims, however, are mutually conflicting.A ship is steered by means of one or more rudders arranged at the stern or, in rare cases, at the bow.There are many types and shapes of rudders, depending upon the type of ship, design of stern, and number of propellers.When a yaw---that is, a change of angle about a vertical axis through the centre of gravity---is started, a turning moment is set up and the ship swings off course unless the swing is corrected by rudder action.This turning effects arises because the hull′s centre of lateral resistance is much nearer the bow than the ship′s centre of gravity.Good course keeping demands directional stability.This is aided by design features that bring the centre of lateral resistance nearer to the ship′s centre of gravity.These measures, however, increase the diameter of the ship′s turning circle, requiring a design compromise.In warships, in vessels operating in confined water, and in tugs, a small turning circle is essential.In merchant ships, rapid manoeuvring is required only in port;accordingly, the everyday function of the rudder is to ensure the maintenance of a steady course with the minimum use of helm.In this sense, turning circle properties are of less practical significance than the effect of small rudder angles.(From ―Encyclopedia Britannica‖, Vol.16, 1980)

Technical Terms

1． manoeuvrability 操纵性 3． surge 纵荡 2． linear displacement 线性位移 4． sway 横荡

5． heave 垂荡 6． veer 变向

7． oscillatory 振荡

8． hydrodynamic 流体动力(学)的 9． Amplitude 振幅 10． acceleration 加速度 11． wind velocity 风速 12． fetch 风区长度，波浪形成区 13． duration 持续时间 14． seaway 航路（道）15． gusts 阵风(雨)16． storm 风暴 17． regular trains of waves 规则波系

18． damp 阻尼 19． bilge keel 舭龙骨 20． finlike 鳍状

21.projection 突出体，投影，规则

22.activated fin stabilitizer 主动式稳定（减摇）鳍 23.gyroscope(gyro)陀螺仪，回转仪 24.steady 稳定 25.flume 槽

26.congested waters 拥挤水域 27.course-keeping 保持航向 28.tug 拖船

29.docking 靠码头 30.helm 操舵，驾驶 31.swing 摆动

32.turning circle 回转圈 33.warship 军舰

34.confined water 受限制水域

Additional Terms and Expressions

1.2.3.4.5.6.7.8.9.10.11.seakeeping 耐波性 seaworthiness 适航性 course 航向 track, path 航迹 drift 横漂 side slip 横移 rudder effect 舵效 sea condition 海况 swell 涌

trochoidal wave 坦谷波 divergent wave 散波

12.13.14.15.16.17.18.natural period 固有周期 slamming 砰击

turning quality 回转性 turning circle 回转圈

turning circle test 回转试验 stopping test 停船试验

free running model test 自由自航模操纵性试验

19.rotating arm test 旋臂试验

20.planar motion mechanism平面运动机构

Notes to the Text

1.In brief, a ship should respond to the action of the sea in such a manner that the amplitudes of its motions and its position never become dangerous, and so that the accelerations it undergoes are kept within reasonable limits.in such a manner that the amplitudes---become dangerous

句为结果状语从句。原一位“以这样的方法，以至于------”，译成中文时可灵活些，例如可把前半句译为“简略说，船舶对海浪的响应方式应使其运动的幅值和所在的位置永远不处于一种危险状态”。

and so that 引出的也是结果状语从句。此句中的it undergoes 为省略了关系代词

that 的定语从句（that 在定语从句中作宾语时，让往被省略），用来修饰 the accelerations.2.of each other 中的of表示（相互间的）方位、距离。

The shipyard is within 5km of shanghai.43 这个船厂离上海5公里以内。

3.if ever 为if they are ever encountered 的简化形式。当从句内的谓语动词为to be，有其主语跟主句的主语相同时，从句中的主语和to be 就可省略。这类连接词除if外，还有when, while, once 以及as 等。

4.Most seas are confused and can be considered as made up of many separate component waves that differ in height and length。

其中的as made up of many separate component waves 是as引导的过去分词短语作为主语补足语。

that 引出的定语从句用来修饰waves.5.This turning effect arises because the hull‘s centre of lateral resistance is much nearer the bow than the ship‘s centre of gravity.because引出的原因状语从句中包含了一个比较级状语从句，than后面的从句中省略了与主句中相同的部分（is near the bow）,这是科技文章中常见的情况。

6.These measures, however, increase the diameter of the ship‘s turning circle, requiring a design compromise.此句中的requiring a design compromise 为现在分词短语，作状语(表示结果)用（参见第七课注释

Lesson Ten The Function of Ship Structural Components The strength deck, bottom, and side shell of a ship act as a box girder in resisting bending and other loads imposed on the structure.The main deck, bottom, and side shell also form a tight envelope to withstand the sea locally.The remaining structure contributes either directly to these functions or indirectly by maintaining the main members in position so that they can act efficiently.The bottom plating is a principal longitudinal member providing the lower flange of hull girder.It is also part of the watertight envelope, and subject to the local water head.At the forward end, it must withstand the dynamic pressure associated with slamming and plating thickness is usually increased to provide the necessary strength.When fitted, the inner bottom also makes a significant contribution to the strength of lower flange.It usually forms a tank boundary for the double bottom tanks and is subject to the local pressure of the liquid contained therein.In addition, it must support the loads from above, usually from cargo placed in the holds.The strength deck forms the principal member of the upper flange, usually provides the upper water tight boundary, and is subject locally to water, cargo, and equipment loadings.The remaining continuous decks, depending on their distance from the neutral axis, contribute to a greater or lesser extent in resisting the longitudinal bending loads.Certain decks which are not continuous fore and aft and not contribute to the longitudinal strength.Locally internal decks are subject to the loads of cargo, equipment, stores, living spaces, and, where they form a tank boundary or barrier against progressive flooding, liquid pressure.The side shell provides the webs for the main hull girder and is an important part of the watertight envelope.It is subject to static water pressure as well as the dynamic effects of pitching, rolling, and wave action.Particularly forward, the plating must be able to withstand the impact of

the seas.Aft, extra plate thickness is beneficial in way of rudders, shaft structure and propellers for strength, panel stiffness, and reduction of vibration.Additional thickness is necessary at the waterline for navigation in ice.Bulkheads are one of the major components of internal structure.Their function in the hull girder depends on their orientation and extent.Main transverse bulkheads act as internal stiffening diaphragms for the girder and resist racking loads, but do not contribute directly to longitudinal strength.Longitudinal bulkheads, on the other hand, if extending more than about one-tenth the length of the ship, do contribute to longitudinal strength and in some ships are nearly as effective as the side shell itself.Bulkheads generally serve structural functions such as forming tank boundaries, supporting decks and load-producing equipment such as kingposts, and adding rigidity to produce vibration.In addition, transverse bulkheads provide subdivision to prevent progressive flooding.All applicable loads must be considered during design.The foregoing structural elements of a ship are basically large sheets of plate whose thicknesses are very small compared with their other dimensions, and which, in general, carry loads both in and normal to their plane.These sheets of plate may be flat or curved, but in either case they must be stiffened in order to perform their required function efficiently.The various stiffing members have several functions:(a)the beams support the deck plating;(b)the girder, in turn, support the beams, transferring the load to the stanchions or bulkheads;(c)the transverse frames support the side shell and the ends of the transverse deck beams and are, in turn, supported by decks and stringers;(d)the stiffeners support the bulkhead plating, and so on.As discussed in detail in section 4, the stiffening members are generally rolled, extruded, flanged, flat, or built-up plate sections with one edge attached to the plate they reinforced.Vertical plates often connect the bottom shell and inner bottom, stiffening both members.If oriented transversely, these plates are called floors, and if longitudinally oriented, center vertical keel or side girder, as appropriate.Stiffening members do not, of course, act independently of the plating to which they are attached.A portion of the plate serves as one flange of the stiffener, and properties such as section modulus and moment of the stiffener must reflect this.The American Bureau of Shipping(ABS)considers a width of plating equal to the stiffener spacing as effective, while Lloyd‘s Register of Shipping(LR)assumes 24 in.to be effective.Stiffening members serve two functions, depending on how they are loaded.In the cases of loads normal to the plate, such as water loading on a transverse bulkhead, the stiffeners assume the load transferred from the plate.In the case of in-plane loads, such as those included in the deck by longitudinal bending of the hull girder, the beams serve to maintain the deck plating in its designed shape.If the deck beams are longitudinally oriented, they will, of course, carry the same primary stress as the plating and may contribute substantially to the hull girder strength.Pillars are used to support deck girders, longitudinal or transverse.These supports, in addition to carrying local loads from cargo, etc, serve to keep the deck and bottom from moving toward each other as a result of longitudinal bending of the hull girder.(From ―Ship Design and Construction‖ by D‘Arcangelo, 1969)

Technical Terms 1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.structural components 结构构件 strength deck 强力甲板 box girder 箱形梁

tight envelope 密闭外壳

longitudinal member 纵向构件 hull girder 船体梁

lower/upper flange 下/上翼缘板 forward/aft end 首/尾端

dynamic pressure 动压力 slamming 砰击 inner bottom 内底 hold 货舱

double bottom 双层底 hold 货舱

neutral axis 中和轴

longitudinal bending 纵向弯曲 longitudinal strength 总纵（纵向）强度 barrier 挡板，屏障 web 腹板

static water pressure 静水压力 impact 冲击

shaft strut 尾轴架

panel stiffness 板格刚性 vibration 振动 bulkhead舱壁 diaphragm 隔壁

racking load 横扭载荷 kingpost 起重柱

29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.rigidity 刚度 subdivision 分舱 sheet 薄板 stanchion 支柱 stringer 船侧纵桁 roll 辗轧 extrude 挤压

flange 拆边，法兰

built-up plate sections 组合型材 bottom shell 外底板 floor 肋板

center vertical keel 中内龙骨，中桁材 side girder 旁桁材，旁纵桁 stiffener 扶强材

section modulus 剖面模数 moment of inertia 惯性矩

The American Bureau of Shipping(ABS)美国验船局 spacing 间距

Lloyd‘s Register of Shipping 劳氏船级社

in-plane 面内 beam 横梁

primary stress 第一类应力

pillar 支柱

deck girder 甲板纵桁 support 支柱（构件）

Additional Terms and Expressions 1.main hull 主船体 12.longitudinal framing 纵骨架式 2.superstructure 上层建筑 13.transverse framing 横骨架式 3.deckhouse 甲板室 14.flat plate keel平板龙骨 4.bridge 桥楼 15.margin plate 内底边板 5.forecastle 首楼 16.bilge bracket 舭肘板 6.poop 尾楼 17.side plate 舷（船）侧板 7.stem 首柱 18.sheer strake 舷顶列板 8.sternpost 尾柱 19.stringer plate 甲板边板 9.rudder post 舵柱 20.shell expansion plan 外板展开图 10.shaft bossing 轴包架 21.bulwark 舷墙 11.framing 骨架 22.hatch coaming 舱口围板

30.hawse pipe 锚链筒 31.bulb plate 球扁钢 32.angle section 角钢 33.T section T型材 34.face plate 面板 35.butt 对接（缝）36.seam 边接（缝）

Notes to the Text 1.The remaining structure contributes either directly to these functions or indirectly by maintaining the main members in position so that they can act efficiently.句中含有either directly---or indirectly---两个并列成分，而在indirectly 后省略了to these functions.by maintaining the main members in position so that---是用来修饰后者的；其中so that they can act efficiently 为目的状语从句。

2.be subject to(n.)受------支配（易受，须经）

be subjected to(n.)受到，经受

Ships subject to the code should survive the normal effects of flooding following assumed hull damage caused by some external force.受本规则约束的船舶应能承受在外力作用下船体遭受假定破碎后正常进水的影响。

All full penetration butt welds of the shell plating of cargo tanks should be subjected to 100 per cent radiographic inspection.液货舱壳板所有全焊透对接焊缝应进行100%的射线照相检验。

课文中的be subject to 均可作为be subjected to 理解，翻译成“承受”，“经受”。

3.to a greater or lesser extent 在较大或较小程度上

4.Locally, internal decks are subject to the loads of cargo, equipment, stores, living spaces, and, where they form a tank boundary or barrier against progressive flooding, liquid pressure.句中的where they form---flooding 为地点状语从句，然而带有条件性质，可理解为承受liquid pressure 的条件。

5.As discussed in detail in Section 4, the stiffening members are generally rolled, extruded, flanged, flat or built-up plate sections with one edge attached to the plate they reinforce.句中的rolled, extruded, flanged, flat or built-up plate 都修饰sections.with one edge attached to the plate 是 with 后带主谓关系的复合短语。they reinforce 为省略关联词（从语中作宾语）的定语从句，修饰前面的the plate.6.If oriented transversely, these plates are called floor, and if longitudinally oriented, center vertical keel or side girder, as appropriate.两个if从句中省略主语及to be，参见第九课注3.在 center vertical keel or side girder 前面省略了these plates are called.As appropriate 可理解为as is appropriate 简化形式，关系代词as代替整个主句，并在从句中作主语，as appropriate, to passenger ships carrying dangerous goods.如第54条规则的要求适合于载运危险货物的客船，应照此办理。

7.The American Bureau of Shipping(ABS)considers a width of plating equal to the stiffener spacing as effective, while Lloyd‘s Register of Shipping(LR)assumes 24 in.to be effective.While 引出并列分句，表示同时存在两种事物的对比。前句的considers… as effective 与后句的assumes… to be effective 结构相似，其中的as effective 和 to be effective 均作宾语补足语。

23.24.25.26.27.28.29.cantilever 悬臂梁

intercostal member 间断构件 cant frame 斜肋骨 pant beam 强胸横梁 lightening hole 减轻孔 bracket 肘板 bracket 肘板 Lesson Eleven

Structural Design, Ship Stresses Structural design

After having established the principal dimensions, form, and general arrangement of the ship, the designer undertakes the problem of providing a structure capable of withstanding the forces which may be imposed upon it.The hull of a steel merchant ship is a complex structure, unique in the field of engineering structures in that it is primarily a plate structure, depending for its major overall strength on the plating of the shell, decks, and in most cases, also on the inner bottom and longitudinal bulkheads.The framing members, each of which has its own function to perform, are designed primarily to maintain the plate membrances to the planned contours and their positions relative to each other when subjected to the external forces of water pressure and breaking seas, as well as to the internal forces caused by the services for which the ship is designed.Unlike most other large engineering structures, the forces supporting the ship‘s hull as well as the loads which may be imposed upon it vary considerably, and in many cases, cannot be determined accurately.As a result, those responsible for the structural design of ships must be guided by established standards.Basic considerations

The problem of the development of a satisfactory structure generally involves the following considerations:

1.It is necessary to establish the sizes of, and to combine effectively, the various component parts so that the structure, with a proper margin of safety, can resist the major overall stresses resulting from longitudinal and transverse bending.2.Each component part must be so designed that it will withstand the local loads imposed upon it from water pressure, breaking seas, the weight of cargo or passenger, and other superimpose loads such as deckhouses, heavy machinery, masts, and so on, including such additional margins as sometimes may be required to meet unusually severe conditions encountered in operation.Rules of classification societies

The various classification societies have continued to modify and improve their rules to keep pace with the records of service experience, an increasing amount of research, and the constantly growing understanding of the scientific principles involved.In the modern rules of the societies, the designer has available to him formulas and tables of scantlings, dimensions of framing shapers, and thicknesses.These are directly applicable to practically all the ordinary types of sea-going merchant vessel being built today, and contain a flexibility of application to vessels of special types.The design of structural features of a merchant ship is greatly influenced by the rules of classification societies;in fact, the principal scantlings of most merchant ships are taken directly from such rules.Scantling are defined as the dimensions and material thicknesses of frames, shell plating, deck plating, and other structures, together with the suitability of the means for protecting openings and making them sufficiently watertight or weathertight.The classification society rules contain a great deal of useful information relating to the design and construction of the various component parts of a ship‘s structure.Scantling can be determined directly from the tables given in these publications.In many cases, a good conception of the usual ―good-practice‖ construction can also be gleaned from the sketches and descriptive matter available from the classification societies.(From ―McGraw-Hill Encyclopedia of Science and Technology‖, Vol.12.1982)Ship stresses

The ship at sea or lying in still water is being constantly subjected to a wide variety of stresses and strains, which result from the action of forces from outside and within the ship.Forces within the ship result from structural weight, cargo, machinery weight and the effects of operating machinery.Exterior forces include the hydrostatic pressure of the water on the hull and the action of the wind and waves.The ship must at all times be able to resist and withstand these stresses and strains throughout its structure.It must therefore be constructed in a

manner, and of such materials, that will provide the necessary strength.The ship must also be able to function efficiently as a cargo-carrying vessel.The various forces acting on a ship are constantly varying as to their degree and frequency.For simplicity, however, they will be considered individually and the particular measures adopted to counter each type of force will be outlined.The forces may initially be classified as static and dynamic.Static forces are due to the

Fig.1 Ship movement------the six degrees of freedom differences in weight and buoyancy which occur at various points along the length of the ship.Dynamic forces result from the ship‘s motion in the action of the wind and waves.A ship is free to move with six degrees of freedom—three linear and three rotational.These motions are described by the terms shown in Figure.1.These static and dynamic forces create longitudinal, transverse and local stresses in the ship‘s structure.Longitudinal stresses are greatest in magnitude and result in bending of the ship along its length.Fig.2 Static loading of a ship‘s structure

Longitudinal stresses

Static loading

If the ship is considered floating in still water, two different forces will be acting upon it along its length.The weight of the ship and its contents will be acting vertically downwards.The buoyancy or vertical component of hydrostatic pressure will be acting upwards.In total, the two forces exactly equal and balance one another such that the ship floats at some particular draught.The centre of the buoyancy force and the centre of the weight will be vertically in line.However, at particular points along the ship‘s length the net effect may be an access of buoyancy or an excess of weight.This net effect produces a loading of the structure, as with a beam.This loading results in shearing forces and bending moments being set up in the ship‘s structure which tend to bend it.The static forces acting on a ship‘s structure are shown in Figure 2(a).This distribution of weight and buoyancy will also result in a variation of load, shear forces and bending moments along the length of the ship, as shown in Figure 2(b)-(d).Depending upon the direction in which the bending moment acts, the ship will bend in a longitudinal vertical plane.The bending moment is known as the still water bending moment(SWBM).Special terms are used to describe the two extreme cases: where the buoyancy amidships exceeds the weight, the ship is said to ―hog‖, and this condition is shown in Figure 3, where the weight amidships exceeds the buoyancy, the ship is said to ―sag‖, and this condition is shown in Figure 4.Excess of buoyancy

Fig.3 Hogging condition

Excess of weight

Fig.4 Sagging condition Dynamic loading If the ship is now considered to be moving among waves, the distribution of weight will be the same.The distribution of buoyancy, however, will vary as a result of the waves.The movement of ship will also introduce dynamic forces.The traditional approach to solving this problem is to convert this dynamic situation into an equivalent static one.To do this, the ship is assumed to be balanced on a static wave of trochoidal form and length equal to the ship.The profile of a wave at sea is considered to be a trochoid.This gives waves where the crests are sharper than the throughts.The wave crest is considered initially at midships and then at the ends of the ship.The maximum hogging and sagging moments will thus occur in the structure for the particular loaded condition considered, as shown in Figure 5.Still water

Wave trough amidships

Wave crest amidships

第五篇：船舶与海洋工程专业英语

船舶与海洋工程专业英语复习笔记

Unit 1

Ship Types Lecture 1

The Criterion of Translation 专业词汇学习

The Family Tree of Merchant Ships 商船分类 Group 1: Ocean Going Ships 远洋船舶 Subgroup 1: Passenger ships 客船

Passenger liners 客班船

Passenger and cargo ship 客货船 Subgroup 2: Cargo carrying ships(tramp or liner)

货船，不定航线、不定日期船或班船

General cargo ship 杂货船

Multipurpose(general purpose)ship 多用途船

Bulk carrier 散装货船, with the special forms:

Combination carrier 兼用船； Collier 运煤船

Ore carrier 矿砂船； OBO 矿、散、油船

Timber carrier 运木船 Tankers, divided into: Crude oil carrier 原油船：VLCC 巨型油船； ULCC 超级油船 Chemical tanker 化学品船 = Product carrier 成品油船 Containerships, including: Conventional containership 常规集装箱船 Hatchcoverless containership 无舱盖集装箱船 Liquified gas carrier, including: LPG 液化石油气船； LNG 液化天然气船 Refrigeration cargo ship(reefer)冷藏船 RoRo ship 滚装船

Barge carrier 载驳船； LASH 载驳船； SEABEE 升降式载驳船

Group 2: Sea and coastal ships, inland waterway ships 近海、沿海和内河船舶

(Cross-channel)ferries(for passengers, cars, or both)渡船 Passenger ships, with the following forms: Conventional liner 常规客班船

Hydrofoil 水翼艇

Hovercraft(air cushion vehicle: ACV)腾气艇、气垫船

Cargo vessels, the subdivision is much the same as above.Cargo-passenger ships 货客船

Pleasure boats 游艇

Barges 驳船

Group 3: Subsidiary ships 辅助船舶

Working ships, including: 工程船

Tug 拖轮； Floating crane 浮吊； Dredger 挖泥船

Salvage ship 打捞船； Drilling vessel 钻井船； Pile-driver 打桩船

Pipe line layer 敷管船； cable layer 布缆船； Dike layer 驻堤船

Icebreaker 破冰船； Firefighting ship 消防船；buoy tender 航标船

Research ship 调查船、研究船； Split hopper barge 开体泥驳

Fishing vessel, including: 渔船

Trawler 拖网渔船； Fish factory ship 鱼品加工船；

Seiner 围网渔船

Others

Supply ship(water, fuel oil)供应船

Training ship 训练船 Navy Ships Navy Armament Gun / heavy gun 枪、炮；

Depth bomb / charge 深水炸弹 Mine 水雷；

Torpedo 鱼雷

Missile 弹道；

Armed aircraft 武装飞机 Group 1: War Ships Subgroup 1: Surface combatant ship 水面舰艇 Patrol boat 巡逻艇；

Gun boat 炮艇

Torpedo boat 鱼雷艇；

Guided missile boat 弹道艇 Submarine hunter 猎潜艇；

Frigate 护卫舰 Destroyer 驱逐舰；

Cruiser 巡洋舰

Helicopter carrier 直升机母舰；

Aircraft carrier 航空母舰 Subgroup 2: Undersea ships 水下舰艇 Submarine, divided into: Conventional powered submarine 常规动力潜艇 Nuclear powered submarine 核潜艇 Group 2: Naval Auxiliary Ships Landing ship(boat)登陆舰/艇；

Minehunter(mine-sweeper)扫雷艇 Minelayer 布雷舰；

Combat stores ship 舰队补给船 Ammunition ship 军火船；

Surveying ship 测量船 Commuter boat(traffic boat)交通艇 课文阅读 Part A The development of ship types over the years has been dictated very largely by the nature of the cargo.The various designs can, to some extent, be divided into general cargo, bulk cargo and passenger vessels.这么多年来船型的发展在很大程度上受制于货物的性质。在某种程度上，各种式样可以划分为杂货船、散货船和客船。

The general cargo carrier is a flexible design of vessel which will go anywhere and carry anything.Special forms of the general cargo carrier include container ships, roll-on/roll-off ships and barge carriers.Bulk cargo may be liquid, solid, or liquefied gas and particular designs of vessel exist for the carriage of each.杂货船是一种灵活的船舶式样，它可以去任何地方载任何货物。杂货船的特殊形式包括集装箱船，滚装船和载驳船。散货可以是液态的、固态的或液化气，针对每一种货物运载都存在着特殊形式的船舶。Passenger-carrying vessels include cruise liners and ferries.Many special types of vessel exist which perform particular functions or are developments of particular aspects of technology.These include multi-hull vessels, hydrofoil and hovercraft.运载旅客的船舶包括（定期）旅游船和渡船。也存在许多特殊的船型，它们发挥特定的功能或是一些特定领域技术发展的产物。这些包括多体船，水翼艇和气垫船。

These various ship types will now be examined in further detail.这些各式各样的船型将予以进一步的讨论。

General cargo ships 常规杂货船

The general cargo ships have several large clear open cargo-carrying spaces or holds.One or more separate decks may be present within the holds and are known as “tween decks”.These provide increased flexibility in loading and unloading and permit cargo segregation as well as improved stability.Access to these holds is by openings in the deck known as hatches.杂货船有几个大而宽敞的载货空间或货舱。舱内可能设一层或更多层分离的甲板，它们被称为“间甲板”。这些间甲板增加了装货与卸货的灵活性，有利于分隔货物以及改善稳性。通向这些货舱的入口是在甲板上设置的开口，它们被成为舱口。

Hatches are made as large as strength considerations permit in order to reduce the amount of horizontal movement of cargo within the ship.Hatch covers are, nowadays, made of steel although older vessels used wood.The hatch covers must be watertight and rest upon coamings around the hatch.The coamings of the upper or weather deck hatches are a reasonable height above the deck to reduce the risk of flooding in heavy seas.只要强度方面允许，舱口升得尽可能大，以减少货物在船内的水平运动的幅度。当今舱口盖由钢铁制成，虽然在一些较旧的船上使用木质舱口盖。舱口盖必须水密并坐落在围着开口的舱口围板上。上甲板或露天甲板舱口的围板离甲板有一个合理的高度，以减少在大浪中货舱进水的风险。

Some form of cargo handling equipment is always fitted which may take the form of derricks and winches or deck cranes.Deck cranes are fitted to many vessels since they reduce cargo handling times and manpower requirements.Some ships have a special heavy-lift derrick fitted which may serve one or more holds.某种形式的起货机总装在这种船上，其形式可以是吊杆和绞车或甲板起重机。甲板起重机装在许多船上因为它们能减少货物搬运时间和人力需求。一些船上装有特殊的重型吊杆，可以为一个或几个货舱服务。

A double bottom is fitted along the ship‟s length and is divided into various tanks.These tanks may be used for fuel or lubricating oil, fresh water or ballast sea water.Fore and aft peak tanks are also fitted and may be used to carry ballast or to suitably trim the ship.Deep tanks are often fitted and can be used to carry liquid cargoes or water ballast.The water ballast tanks may be filled when the ship is only partially loaded in order to provide a sufficient draught for stability and total propeller immersion.沿船长方向设置双层底，并将其划分成各种液舱。这些液舱可用作燃油舱或滑油舱，淡水舱或压载海水舱。船上也设置首尾尖舱，可用来装压载水或用来适当地调准纵倾。船上常常设深舱，可用来装载液体货物或压载水。当船舶仅部分装载时，压载水舱可灌水以便为稳性和螺旋桨总浸深提高足够的吃水。There is usually one hold aft the accommodation and machinery space.This arrangement improves the trim of the vessel when it is partially loaded.The range of size for general cargo ships is currently from 2,000 to 15,000 displacement tones with speeds from 12 to 18 knots.住舱和机舱之后通常设一个货舱。这种布置在船舶部分装载时能改善船舶的纵倾。杂货船的尺度范围当前为2000至15000排水吨，速度为12至18节。

Refrigerated cargo ships 冷藏船

The refrigerated cargo ship differs from the general cargo ship in that it carries perishable goods.A refrigeration system is therefore necessary to provide low temperature holds for these cargoes.The holds and the various „tween decks are insulated to reduce heat transfer.The cargo may be carried frozen or chilled and various holds may be at different temperatures according to the cargo requirements.冷藏船与杂货船的不同之处在于装载易变质货物。因为必须设制冷系统为这些货物提供低温货舱。货舱和各层间甲板都作绝缘处理以减少热传递。货物可以冷冻或冷藏运载，而且根据货物的要求各个货舱可以调至不同的温度。

This type of vessel is usually faster than a general cargo ship, having speeds up to 22 knots.It is essentially a cargo liner having set schedules and sailing between fixed terminal ports.Up to twelve passengers may be carried on some of these vessels.这种船通常比杂货船快，具有高达22节的航速。它基本上是一种定期货船，有既定的计划并在固定的港口之间航行。这些船有的可以携带多到12名的旅客。

Container ships 集装箱船

A container is a re-usable box of 2,435 mm by 2,435 mm section, with lengths of either 6,055, 9,125 or 12,190 mm.Container are now used for most general cargoes and liquid-carrying versions also exist.Refrigerated versions are also in use which may have their own independent refrigeration plant or be supplied with cooled air from the ship‟s refrigeration system.集装箱是一只可反复使用的箱子，宽度和高度为2435mmX2435mm，长度6055，9125或12190mm三种。现在集装箱船用于装载大多数杂货，而且也有转载液体的集装箱。冷藏集装箱也在使用，它可以有自己独立的制冷装置或由船舶的制冷系统提供冷气。

The cargo-carrying section of the ship is divided into several holds each of which has a hatch opening the full width and length of the hold.The containers are racked in special frameworks and stacked one upon the other within the hold space.Cargo handling is therefore only the vertical movement of the container by a special quayside crane.Containers may also be stacked on the flush top hatch covers.Special lashing arrangements are used to secure this deck cargo.船舶的载货区划分成几个货舱，每一货舱的舱口大小与货舱的全宽和全长一样。集装箱放在特殊的框架内，并在货舱空间内一只箱子堆在另一只箱子上。因此货物搬运仅仅是用特殊的岸壁起重机使集装箱作垂向运动。集装箱也可以堆放在顶部平坦的舱口盖上。这种甲板货物用特殊的绑扎装置来固定。

The various cargo holds are separated by a deep web-framed structure to provide the ship with transverse strength.The ship structure outboard of the container holds on either side is a box-like arrangement of wing tanks which provides longitudinal strength to the structure.These wing tanks may be used for water ballast and can be arranged to counter the heeling of the ship when discharging containers.A double bottom is also fitted which adds to the longitudinal strength and provides additional ballast space.各个货舱用强框架结构隔开，为船舶提供横向强度。集装箱舱外侧船舶两舷的结构为箱形布置的边舱，为结构提供纵向强度。这些边舱可以用来装压载水，并能安排来抵抗船舶卸箱时产生的横斜。船舶也设双层底，它增加了纵向强度并提供额外的压载空间。

The accommodation and machinery spaces are usually located aft to provide the maximum length of full-boded ship for container stowage.Cargo-handling equipment is rarely fitted, since these ships travel between specially equipped terminals to ensure rapid loading and discharge.Container ship sizes vary considerably, with container carrying capacities from 1,000 to 2,500 TEU‟s or more.The twenty foot equivalent unit(TEU)represents a 20 ft(6,055 mm)“standard” container.Container ships are much faster than most cargo ships, with speeds up to 30 knots.They operate as liners on set schedules between fixed ports.居住舱室和机舱通常位于船尾，以提供最大长度的丰满船体用语储藏集装箱。起货设备很少安装，因为这些船舶行驶在特殊装备的终点港间以确保迅速装卸。集装箱船的尺度变化很大，其集装箱装载能力从1000箱到2500箱或更多。二十英尺相当单元（TEU）代表二十英尺（6055mm）“标准”集装箱。集装箱船比大多数船快得多，速度高达30节。它们作为定期航船按既定计划在固定港口间运营。

Roll-on / roll-off ships 滚装船

This vessel was originally designed for wheeled cargo, usually in the form of trailers.The cargo could be rapidly loaded and unloaded by stern or bow ramps and sometimes sideports for smaller vehicles.The loss of public capacity due to undercarriages and clearances has resulted in many roll-on roll-off vessels being also adapted to carry containers.这种船原先设计用于有轮货物，通常是拖车的形式。这种货物可通过尾或首跳板迅速装卸，有时候小型车辆用舷门。车架下空间和上部间隙损失了装卸容积，因而许多滚装船也设计成适于装载集装箱。

The cargo-carrying section of the ship is a large open deck with a loading ramp usually at the after end.Internal ramps lead from the loading deck to the other „tween deck spaces.The cargo may be driven aboard under its own power or loaded by straddle carriers or fork lift trucks.One or more hatches may be provided for containers or general cargo and will be served by one or more deck cranes.Arrangements may be provided on deck for stowing containers.Some roll-on roll-off(Ro-Ro)vessels also have hatch covers to enable loading of lower decks with containers.Where cargo(with or without wheels)is loaded and discharged by cranes the term lift-on lift-off(Lo-Lo)is used.船舶的装货区域是大而宽敞的甲板，在其尾端通常设置装载坡道。内部坡道由装载甲板通向其他间甲板区域。货物可用自己的动力开上船，也可用跨运车或叉车装上船。为了装运集装箱或杂货，船上可有一个或几个舱口，并配有一台或几台甲板吊车。甲板上也可以布置来堆放集装箱。某些滚装船也时舱口盖，以便在下层甲板上装载集装箱。当货物（有轮或无轮）用起重机装卸时，就用“吊上-吊下”（LO-LO）这一术语。

The ship‟s structure outboard of the cargo decks is a box-like arrangement of wing tanks to provide longitudinal strength.A double bottom is also fitted along the complete length.The accommodation is located aft and also the low-height machinery space.Only a narrow machinery casing actually penetrates the loading deck.Sizes range considerably with about 16,000 dwt(28,000 displacement tonne)being quite common.High speeds in the region of 18~22 knots are usual.货物加班舷侧部分的船体结构是箱形布置的边舱，以提供纵向强度。这种船也在全厂范围内设置双层底。住舱还有低高度的机舱都位于船尾。实际上仅有狭窄的机舱棚穿国装载甲板。尺度变化很大，16000载重吨（28000排水吨）相当普遍。速度通常高达18至22节。

Barge carrier 载驳船

This type of vessel is a variation of the container ship, instead of containers, standard barges are carried into which the cargo has been previously loaded.The barges, once unloaded, are towed away by tugs and return cargo barges are loaded.Minimal or even no port facilities are required and the system is particularly suited to countries with vast inland waterways.Two particular types will be described, the LASH(Lighter Aboard Ship)and the SEABEE.这种船是集装箱船的派生船型，所装载的不是集装箱，而是标准的驳船，驳船中预先装进了货物。驳船一当卸下就被拖轮带走，回来的驳船已装载。这一运输系统很少或甚至不需要港口设备，它特别适合于有大量内陆水道的国家。这里要介绍两种特殊类型，即载驳船（驳船上船）和升降式载驳船。

The LASH ship carries barges, capable of holding up to 00 tonne of cargo, which are 18.75 m(61.5 ft)long, 9.5m(31ft)beam and 3.96 m(13 ft)deep.About eighty barges are carried stacked in holds much the same as containers with some as deck cargo on top of the hatch covers.The barges are loaded and unloaded using a traveling gantry crane capable of lifting over 500 tonne.Actual loading and discharge takes place between extended “arms” at the after end of the ship.The shi structure around the barges is similar to the container ship.The accommodation is located forward whereas the machinery space is one hold space forward of the stern.LASH ships are large, in the region of 45,000 deadweight tones, with speeds in the region of 18 knots.载驳船载运驳船，驳船能装400吨货物，它长18.75m(61.5ft)，宽9.5m(31ft)，深3.96m(13ft)。与集装箱很相像，大约8只驳船放在货舱内，一些作为甲板货物放在舱口盖上面。用一台举力超过500吨的移动式门架起重机来装卸驳船。实际装卸作业在船尾的延伸臂间进行。装驳区周围的船体结构与集装箱船相似。住舱位于船首，而机舱在船尾一个货舱之前。载驳船很大，在45000载重吨左右，速度在18节左右。

The SEABEE is somewhat larger than the LASH ship and carries thirty-eight barges.Each barge may be loaded with up to 1,000 tonne of cargo and is 29.72 m long, by 10.67 m beam and 3.81 m depth.The barges are loaded on board by an elevator located at the stern.They are then winched forward along the various decks.升降式载驳船比载驳船稍微大些，能装载38个驳船；每一驳船可载1000吨货物，它长29.72m，宽10.67m，深3.81m。驳船用位于船尾的一台升降机上船；然后用绞车沿着各层甲板拖向船首。

Deck hatch opening does not exist and the decks are sealed at the after end by large watertight doors.Two „tween decks and the weather deck are used to store the barges.The machinery space and various bunker tanks are located beneath these „tween decks.在甲板上不存在舱口，各层甲板在尾端用大型水密门密封。两层间甲板和露天甲板用来存放驳船。机舱和各种燃料舱位于这些间甲板下方。

The machinery space also extends into the box-like structure outboard of the barges on either side of the ship.The accommodation is also located here together with several ballast tanks.A barge winch room is located forward of the barge decks and provides the machinery for horizontal movement of the barges.The SEABEE is physically about the same size as the LASH ship but with a slightly smaller deadweight of 38,000 tonnes.The speed is similarly in the region of 18 knots.机舱延伸到驳船外侧船舶两舷箱形结构内。住舱也设在此处，还加上几个压载舱。早驳船甲板的前端设置了驳船绞车房，并布置了用于驳船水平运动的机械。升降式载驳船的实体尺度与载驳船大致相同，但载重量略小一些，约38000吨。速度也相似在18节左右。

Despite their being specialist vessels both LASH and SEABEE can be used for other cargoes.Each can be used to carry containers and the SEABEE will also take Ro-Ro cargo.Other variations of barge carriers have been proposed such as the barge carrying catamaran vessel(BACAT).Tug-barge systems have also been considered where the “Ship” is actually a number of linked barges with a separable propulsion unit.尽管它们是专用船，载驳船和升降式载驳船能用于其他货物。每一种船可用来装载集装箱，而升降式载驳船也能携带滚装货。载驳船的其他派生船型已经被提议，如装载双体船的驳船（简称BACAT）。还考虑了“拖轮-驳船”系统，系统中“船舶”实际上是一些相连接的驳船，配备一个可分离的推进单元。

Oil tankers 油船

The demand for crude oil is constantly increasing.Oil tankers, in particular crude carriers, have significantly increased in size in order to obtain the economies of scale.Designations such as ULCC(Ultra Large Crude Carrier)and VLCC(Very Large Crude Carrier)have been used for these huge vessels.Crude oil tankers with deadweight tonnages in excess half a million have been built although the current trend(1985)is for somewhat smaller(100,000~150,000 dwt)vessels.After the crude oil is refined the various products obtained are transported in product carriers.The refined products carried in these vessels include gas oil, aviation fuel and kerosene.对原油的需求在不断地增加。油船特别是原油船已显著地增加了尺度以获得规模经济。诸如ULCC（超级油轮）和VLCC（巨型油轮）这样的名称已用于这些巨大的船舶。载重吨位超过五百万的原油船也已制造，尽管当前（1985）的趋势是稍微小一点的船舶（十到十五万载重吨）。原油经过提炼后，得到的各种产品用成品油船来装载。这些船所装的提炼产品包括汽油，航空燃油和煤油。

The cargo carrying section of the oil tanker is divided into individual tanks by longitudinal and transverse bulkheads.The size and location of these cargo tanks is dictated by the International Maritime Organization Convention MARPOL 1973/78.This Convention and its Protocol of 1978 further requires the use of segregated ballast tanks(SBT)and their location such that provide a barrier against accidental oil spillage.An oil tanker when on a ballast voyage must use only its segregated ballast tanks in order to achieve a safe operating condition.油船载货区域用纵横舱壁分割成各个液舱。这些舱的尺寸和位置由国际海事组织公约MARPOL 1973/78所规定。这一公约及其1978年协议进一步要求采用隔离压载水舱（SBT）和其位置必须能提供一道屏障以抵御油泄漏事故。油船在压载航行时必须只使用它的隔离压载水舱以便获得一种安全的运行状况。

The arrangement of a 105,000 dwt crude oil tanker which satisfies these requirements is as follows.The cargo carrying tanks include the seven centre tanks, four pairs of wing tanks and two slop tanks.The segregated ballast tanks include all double bottom tanks beneath the cargo tanks, two pairs of wing tanks and the force and aft peak tanks.The cargo is discharged by cargo pumps fitted in the aft pump room.Each tank has its own suction arrangement which connects to the pumps, and a network of piping discharges the cargo to the deck from where it is pumped ashore.一艘满足这些要求的105，000载重吨原油船，其总布置如下。载货的液舱包括七个中央舱、四对边舱和两个污油舱。隔离压载水舱包括货油舱下的全部双层底液舱、两对边舱以及首尾尖舱。货物由设在后泵房的货油泵卸出。每一油舱都有自己的吸油装置，它与油泵相连，一组管路将货油输送到甲板，再从甲板泵送上岸。

Considerable amounts of piping are visible on the deck running from the after pump room to the discharge manifolds positioned at midships, port and starboard.Hose-handling derricks are fitted port and starboard near the manifolds.The accommodation and machinery spaces are located aft and separated from the tank region by a cofferdam.The range of size for crude oil tankers is enormous, beginning at about 20,000 dwt and extending beyond 500,000 dwt.Speeds range from 12 to 16 knots.在甲板上可以看到大量管路从后泵房走向位于左右舷船中的卸油分配阀箱。软管搬运吊架设在左右舷靠近分配阀箱处。住舱和机舱位于船尾，并用隔离舱与油舱区分开。原油船的尺度范围是巨大的，从二万载重吨直到超过五十万载重吨。速度范围是12至16节。

Product carrier at oil tankers which carry the refined products of crude oil.The cargo tank arrangement is again dictated by MARPOL 73/78.Individual “parcels” of various products may be carried at any one time which resulted in several separate loading and discharging piping systems.The tank surface is usually coated to prevent contamination and enable a high standard of tank cleanliness to be achieved after discharge.The current size range is from about 18,000 up to 75,000 dwt with speeds of about 14~16 knots.成品油船是能装载原油炼出产品的油船。同样，其油舱布置受MARPOL 73/78的约束。各种产品的一个个“包裹”可以随时一起装载，这导致了几套分离的装卸管系。油舱表面通常有可防止玷污的涂层，同时也可在卸货后获得高标准的油舱清洁度。目前的尺度范围约18000至75000载重吨，速度为14至16节。

Bulk carriers 散货船

The economies of scale have also been gained in the bulk carriage of cargoes such as grain, sugar and ore.A bulk carrier is a single-deck vessel with the cargo carrying sections of the ship divided into holds or tanks.The hold or tank arrangements vary according to the range of cargoes to be carried.Combination carriers are bulk carriers which have been designed to carry any one of several bulk cargoes on a particular voyage, e.g.ore or crude oil or dry bulk cargo.诸如谷粒、糖和矿砂等货物的大宗运载也赢得了规模经济效益。散装货船是单甲板船，船舶的载货区域划分成几个货舱或液舱。货舱或液舱的布置根据所载货物的种类而变化。兼用船是散货船，它们被设计成在特定的航程中装载几种散货中的任何一种，例如矿砂、油或干散货。In a general-purpose bulk carrier, only the central section of the hold is used for cargo.The partitioned tanks which surround the hold are used for ballast purposes when on ballast voyages.The upper, or saddle, tanks may be ballasted in order to raise the ship‟s centre of gravity when a low density cargo is carried.This hold shape also results in a self-trimming cargo.During unloading the bulk cargo falls into the space below the hatchway and enables the use of grabs or other mechanical unloaders.Large hatchways are a particular feature of bulk carriers since they reduce cargo handling time during loading and unloading.在多用途船散货船上，只有货舱的中央部位用来装货。货舱周围被分隔的液舱在空载时用于压载目的。上边舱或鞍形舱可以装压载，以便在装低密度货物时提高船舶的重心。这种货舱形状也造成货物自我调平。在卸载时，散货落到舱口下方，便于抓斗或其他机械卸货装置的使用。大舱口是散货船的明显特点，因为这可减少装卸作业中货物搬运时间。

An ore carrier has two longitudinal bulkheads which divide the cargo section into wing tanks port and starboard and a center hold which is used for ore.A deep double bottom is a particular feature of ore carriers.Ore, being a dense cargo, would have a very low centre of gravity if placed in the hold of a normal ship.This would lead to an excess of stability in the fully loaded condition.The deep double bottom serves to raise the centre of gravity of the very dense cargo.The behaviour of the vessel is thus much improved.On ballast voyages the wing tanks and the double bottoms ballast capacity.The cross-section would be similar to that for an ore / oil carrier.矿砂船有两道纵壁，从而将载货区域分隔成左右舷的边舱和一个中央货舱；中央舱用语装载矿砂。矿砂船的明显特点是双层底高。矿砂因密度大，如果装在普通船的货舱里其重心会很低。这在满载的状况下会导致稳性过度。高双层底用来提高这种密度货物的重心。船舶的性能因此会改善许多。在压载航行时边舱和双层底提供压载能力。该船的横截面与矿/油船的相似。

An ore / oil carrier uses two longitudinal bulkheads to divide the cargo section into centre and wing tanks which are used for the carriage of oil cargoes.When a cargo of ore is carried, only the centre tank section is used for cargo.A double bottom is fitted but is used only for water ballast.The bulkheads and hatches must be oiltight.矿/油船用两道纵壁将载货区域分隔成中央货舱和左右边舱，边舱用来装油。当装载矿砂时，仅中央舱部位用来装货。船也设置双层底，但只用来装压载水。舱壁和舱口必须油密。

The ore / bulk / oil(OBO)bulk carrier is currently the most popular combination bulk carrier.It has a cargo carrying cross-section similar to the general bulk carrier.The structure is, however, significantly stronger, since the bulkhead must be oiltight and the double bottom must withstand the high density ore load.Only the central tank or hold carries cargo, the other tank areas being ballast-only spaces, except the double bottom which may carry oil fuel or fresh water.矿/散/油船（OBO）是目前最流行的兼用散货船。其载货区横截面与多用途散货船类似。但其结构要强的多，因为其舱壁必须油密且双层底必须承受高密度矿砂的载荷。仅中央液舱或中央货舱装卸货物，但双层底除外，它可装燃油或淡水。

Large hatches are a feature of all bulk carriers, in order to facilitate rapid simple cargo handling.Many bulk carriers do not carry cargo-handling equipment, since they trade between special terminals which have special equipment.Where cargo handling gear is fitted(geared bulk carriers), this does make the vessel more flexible.Combination carriers handling oil cargoes have their own cargo pumps and piping systems for discharging oil.They will also be required to conform to the requirements of MARPOL 73/78.Deadweight capacities range from small to upwards of 200,000 tonnes.Speeds are in the range of 12~16 knots.大舱口是所有散货船的一个特点，以便促使货物搬运既迅速又简单。许多散货船没有起货设备，因为它们在有特殊装备的特定港口之间运行。安装起货机后（自装卸散装货船），确实能使船舶更加灵活。装油的兼用散货船有其自己的货泵和管系用于卸油。它们也被要求满足MARPOL 73/78规定。载重量能力范围从小到二十万吨。速度在12到16节。

Part B（节选）

Liquefied gas carriers 液化天然气船

The bulk transport of natural gases in liquefied form began in 1959 and has steadily increased since then.Specialist ships are now used to carry the various types of gases in a variety of tank systems, combined with arrangements for pressurizing and refrigerating the gas.大宗运输液态形式的天然气始于1959年，从那时起一直稳步增长。现在用专用船将各种形式的气体装在各种液舱系统里，这种系统结合了给气体加压和制冷的措施。

Natural gas is found and released as a result of oil-drilling operations.It is a mixture of methane, ethane, propane, butane and pentane.The heavier gases, propane and butane, are termed “petroleum gases”.The remainder, which consists largely of methane, is known as “natural gas”.The properties, and therefore the behaviour, of these two basic groups vary considerably, thus requiring different means of containment and storage during transportation.天然气是作为石油钻探作业成果被找到和释放的。它是甲烷，乙烷，丙烷，丁烷和戊烷的混合物。较重的气体丙烷和丁烷被称为“石油气”。其余的气体，主要由甲烷组成，被称为“天然气”。这两个基本组合的性质，进而性能，变化相当大，于是在运输过程中要求用不同的手段来容纳和储藏。

Passenger ships 客船

Passenger ships can be considered in two categories, the luxury liner and the ocean-going ferry.The luxury liner is dedicated to the luxurious transport of its human “cargo”.The ocean-going ferry provides a necessary link in a transport system between countries.It often carries roll-on roll-off in addition to its passengers.客船可以分为两类，即豪华班船和远洋渡船。豪华班船是专用于旅客运输的高档交通工具。远洋渡船给国与国之间的运输系统提供了必要的纽带。它不仅运送旅客，还可以运载滚装货。

Luxury passenger liners are nowadays considered to be cruise liners in that they provide luxurious transport between interesting destinations in pleasure climates.The passenger is provided with a superior standard of accommodation and leisure facilities.This result in large amount of superstructure as a prominent feature of the vessel.The many tiers of decks are fitted with large open lounges, ballrooms, swimming pools and promenade areas.Aesthetically pleasing lines are evident with well-raked clipper-type bows and unusual funnel shapes.Stabilizers are fitted to reduce rolling and bow thrusters are used to improve maneuverability.The cruise liner ranges in size up to passenger-carrying capacities of around 1,200(45,000 gt)although a few older large vessels are in service.Speeds are usually high in the region of 22 knots.由于豪华班船在气候宜人的季节里为旅游胜地之间提供高档的客运服务，所以现在通常作为旅游班轮。它为旅客提供了高级的住宿和休闲设施。这就造成这类船舶的显著特征是拥有大量的上层建筑。许多层甲板上装备了大型露天休息室、舞厅、游泳池和散步区。从审美的角度看，这类船舶明显具有充分前倾的飞剪式船首和不同寻常的烟囱造型。稳定器被用来减少横摇，而首部推力器被用来改善操纵性。虽然一些更老、更大的船仍在服役，这类巡航班船的载客能力可大到约1200人（45 000总吨），航速通常高达22节左右。

Ocean-going ferries are a combination of roll-on roll-off and passenger vessels.The vessel is therefore made up in three layers, the lower machinery space, the car decks and the passenger accommodation.A large stern door and sometimes also a lifting bow providing access for the wheeled cargo to the various decks which are connected by ramps.The passenger accommodation will vary according to the length of the journey.For short-haul or channel crossings public rooms with aircraft-type seats will be provided.For long distance ferries cabins and leisure facilities will be provided which may be up to the standard of cruise liners.Stabilizers and bow thrusters are also usually fitted to ocean-going ferries.Size will vary according to rout requirements and speeds are high at around 20~22 knots.远洋渡船是滚装船和客船的一种结合。因此这种船由三层组成，底层的机舱、车辆甲板和旅客住舱。位于船尾的一扇大门，有时还有提升式船首，为滚装货到达由坡道连接的不同层甲板提供了通道。客舱的标准根据旅途的长短有所区别。对于短途或横渡海峡的渡船，公共房间将配备航空式座椅。对于长途渡船，其住舱和休闲设施的豪华程度可达到巡航班船的标准。远洋渡船通常也安装稳定器和首部推力器。船的尺度将根据航线需要而不同，航速则高达20至22节左右。

Unit 2

Ship Performances Lecture 2

The Treatment of Words 专业词汇学习

Spaces Aboard Ships Zone 1: After End(aft peak tank &.Poop)

Aft ballast tank 尾压载舱

Fresh water tank 淡水舱

Steering gear room(tiller room)舵机舱 Zone 2: Machinery Space(engine room)

E.R.double bottom, with the following subdivision:

Fuel tank

燃油舱；

Lube tank

滑油舱

Cofferdam

隔离舱；

Void space

空舱

Sea chest

海水箱；

Shaft tunnel 轴隧

E.R.grating

机舱踏格；E.R.Flats

机舱平台

Central control room 集控室；

Workshop 车间

Engine casing

机舱棚；

Funnel

烟囱 Zone 3: Cargo Space

货舱

In case of TK / OBO：

Central tank

中央舱

Wing tank, can be used as: 边舱

Ballast tank

压载舱；

Slop tank 污水舱，污油舱

Double bottom

双层底

In case of BC:

Cargo hold

货舱

Upper hopper tank

上边舱

Lower hopper / bilge tank 下边舱，底边舱

In case of CS:

Wing tank, can be divided vertically:

Torsion box 抗扭箱；

Ballast tank 压载舱

Bilge tank

底边舱

Zone 4: Fore End(fore peak tank & forecastle)

Bow thruster room(if any)侧推舱

Chain locker

锚链舱

Fore ballast tank

首压载舱

Forecastle, can be subdivided into: 首楼

Paint room

油漆间

Store(boatswain‟s store)

帆缆舱 Zone 5: Upper Deck

上甲板

Deck house

甲板室

Hatch coaming

舱口围板

Winch control room 绞车控制室

Store

储藏室

Zone 6: Accommodation(living quarters)上层建筑

Poop deck, generally with:

尾楼甲板

Provision room

食品库

Reefer room

冷藏库

Galley

厨房

Crew‟s mess room

船员餐厅

Accommodation deck, generally with: 起居甲板

Air conditioning room 空调机房

Laundry

洗衣机房

Crew‟s room

船员卧室

Officer‟s mess room

高级船员餐厅

Officer‟s room

高级船员卧室

Boat deck, generally with: 救生甲板

Captain‟s room

船长室

Gyro room

电罗经室

Navigation deck(bridge deck), with: 驾驶甲板

Wheelhouse

驾驶室

Radio office

报房

Chart room

海图室

Compass deck

罗经甲板 Terms of Ship Performance 1.Buoyancy 浮力方面 Floating conditions 浮态

Even keel 正浮；

Trim 纵倾 Trim by the bow / stem

首倾 Trim by the stern = stern

尾倾 Hell / list

横倾 Centers

中心

Center of gravity

重心； Center of buoyancy 浮心 Center of floatation 漂心； Metacenter

稳心 Centroid

形心，质心 2.Stability 稳性方面

Transverse / lateral stability 横稳性； Longitudinal stability 纵稳性

Initial / metacentric stability 初稳性

Stability at large angles of inclination 大倾角稳性

Intact stability 完整稳性

Damaged / impaired / flooded stability 破舱稳性 3.Resistance 阻力

Wave-making resistance 兴波阻力；Viscous resistance

粘性阻力 Friction resistance

摩擦阻力；Eddy-making resistance 旋涡阻力 Wave-breaking resistance 破波阻力；Appendage resistance

附体阻力 Wind(age)resistance

风阻力 1．Motion 运动

Ship: Three translation: 三个平移分量

Surging 纵荡；Swaying 横荡；Heaving 垂荡，升沉

Three rotation 三个转动分量

Wave: Head sea(345~15 degrees)

顶浪，迎浪

Bow sea(15~75, 285~345)

首斜浪

Athwart sea(75~105, 255~285)

横浪

Quartering sea(105~165,195~255)尾斜浪

Stern sea(165~195 degrees)

尾浪 2．Others Insubmersibility

不沉性；

Rapidity

快速性 Endurance

续航力；

Maneuverability 操纵性 Course keeping

航向保持性；Sea-keeping

耐波性 Sea-worthiness

适航性 课文阅读 Part A Hydrostatic curves 静水力曲线

It has been shown how the displacement of a ship and the position of the centre of buoyancy can be calculated and also how the position of the metacentres and the center of floatation can be determined.It is customary to calculate all these quantities for about six or seven waterlines parallel to the base and spaced one metre(3 or 4 ft)apart.The results so obtained are plotted in a diagram with draught measured vertically.The curves drawn in this way are called “hydrostatic curves”.已经说明船舶的排水量和浮心位置是如何计算的以及稳心和漂心位置是如何确定的。习惯上所有这些数据都按六至七条水线来计算，这些水线与基线平行且相隔一米（3或4英尺）。如此得到的结果画在一张图上，吃水垂直量取。这样绘制的曲线称为“静水力曲线”。Two curves of displacement are shown.One is called the “moulded displacement” and it is the displacement obtained to the moulded line of the ship between perpendiculars.To obtain the extreme displacement it is necessary to add on to this shell displacement, the displacement of the cruiser stern and bulb forward, if fitted, and in the case of multiple screw ships the displacement of the bossing enclosing the shafting.Sometimes the displacement of the rudder and propeller and shafting are included in the extreme displacement.两条排水量曲线需要说明。一条叫做“型排水量”曲线，它是根据两垂线间的船体型线得出的排水量。要得到最大排水量就必须在型排水量的基数上再加上外板排水量，如果没有巡洋船尾和球鼻首时还应该加上这两者的排水量，以及如果是多螺旋桨船时尚应加上包封轴系的轴壳的排水量。有时舵、螺旋桨和桨轴的排水量也计入最大排水量。

It is also important to correct the position of the centre of buoyancy for these items, and this would apply particularly to the longitudinal position of the centre of buoyancy since the volume of such items as bossing can have a major effect.就这些项目来修正浮心位置也很重要，这特别适用于浮心的纵向位置，因为如轴壳这类项目可能对排水体积有重要影响。

With regard to the displacement of the shell, this is determined by first of all calculating the wetted surface area.This area when multiplied by the mean thickness of the shell plating will give the volume displaced by the shell.The wetted surface area is not easy to calculate since the outside surface of a ship has double curvature.It can be approximated to by taking girths round the various sections and then applying Simpson‟s rule to find the area.The procedure ignores the curvature of the hull surface in the fore and aft direction(the “obliquity effect” as it is sometimes called), but this is often not of great magnitude.关于壳板的排水量。这首先要通过计算湿表面面积来确定。这一面积上外板的平均厚度可得到壳板的排水体积。但湿表面面积不是容易计算的，因为船体外表面具有双向曲度。这可以近似地量取各横剖面的围长然后用辛普生法得出湿面积。这一过程忽略了船体表面首尾方向的曲度（有时也称作“倾斜效应”），但通常影响程度不大。

Shell displacement represents only a small percentage of the total displacement of a ship but is of sufficient magnitude to justify its inclusion in the calculation of the displacement.In a large modern vessel it could amount to many hundreds of tonnes.船壳板排水量仅占有船舶总排水量很小的百分比，但其数值足够证明将其纳入排水量计算是正确的。大型现代船舶这一数值可能高达几百吨。

There is a curve which gives the increase in displacement for unit increase in draught.If A is the area of the waterplane at which the ship is floating, then for unit increase in draught the volume added is Ax1 assuming the ship to be wall sided in the neighbourhood of the waterline.It follows that increase in displacement = ρgA.When imperial unit are used the weight per unit volume of sea water is given as 1/35 ton/ft3, so that increase in displacement = A/35, and A in square feet, which may be called the “ton per foot immersion”.As this is quite a large quantity it was usually divided by 12 to give “ton per inch immersion”.Therefore: TPI = A/420 for sea water When using SI units it is probably more convenient to leave this quantity in the form given above, i.e., ρgA where ρ is the density in kg/m3, g is the acceleration due to gravity and A is the waterplane area in m2.For ρ = 1 025 kg/m3 and g = 9.81 m/s2: Increase in displacement per metre increase in draught =1 025 X 9.81 X 1 X A = 10 055 AN =0.010 055 A MN For 1 cm immersion this would become 0.000,100,55 A MN.有一根曲线给出单位吃水增加与排水量增加的关系。若A是船舶漂浮处的水线面面积，则单位吃水增加时排水体积的增加为AX1，假设船舶水线附近的舷侧是直壁状的。于是排水量增加 = ρgA。如果使用英制，每单位体积海水的重量给定为1/35 ton/ft3，那么排水量增加 = A/35，其中A 的单位是平方英尺，这一增量称作“浸水英吨/英尺”。鉴于这是一个很大的数量，通常将其除以12给出“浸水英吨/英尺”。因此：对海水浸水英吨/英寸= A/ 420。

3使用国际单位时，保留上面给出的形式可能更方便，即ρgA，式中：ρ是密度单位为kg/m，g是重力加速度而A是水线面面积，单位为m2。当g = 9.81 m/s2时：吃水每增加1米时排水量增加 = 1 025 X 9.81 X 1 X A = 10 055 AN 对于每厘米浸水这变成0.000,100,55 A MN。

The increase in displacement per unit increase in draught is useful in approximate calculations when weights are added to the ship.The weight added divided by this quantity gives the parallel sinkage of the ship.The calculation is only reasonably correct for the addition of relatively small weights, since the increase in displacement per unit increase of draught varies with the draught.当船舶增加重量时，单位吃水增加后排水量的增加在近似计算中是有用的。增加的重量除以这一数值可给出船舶的平行下沉量。只有当增加的重量相对较小时这种计算才有合理的正确性，因为单位吃水增加后排水量增加将随吃水而变化。

Hydrostatic curves are most useful in working out the end draughts and the stability of a ship as represented by metacentric height in various conditions of loading.This is done for all the calculations which have been discussed.The input data required consist of ordinates at various waterlines defining the form of a ship.When this is put into the computer the program calculates all the quantities necessary for plotting hydrostatic curves.It can be done in a very short space of time, whereas in the days of hand calculations the production of a set of hydrostatic curves required about two man weeks.静水力曲线在求得船舶最终吃水和稳性的过程中非常有用；稳性是用各种装载状态下的稳心高度来表示的。我们已讨论过的全部计算都是这样做的。所需的输入数据由定义船舶形状的各水线的坐标组成。当输入计算机后程序计算绘制静水力曲线所需的全部数值。这能在很短的时间内完成，而在手算的年代要算出一套静水力曲线要花约一人两周工作量。

Ship resistance 船舶阻力

A ship when at rest in still water experiences hydrostatic pressures which act normally to the immersed surface.It has already been stated when dealing with buoyancy and stability problems that the forces generated by these pressures have a vertical resultant which is exactly equal to the gravitational force acting on the mass of the ship, i.e., is equal to the weight of the ship.If the forces due to the hydrostatic pressure are resolved in the force and aft and the transverse directions it will be found that their resultants in both of these directions are zero.Consider what happens when the ship moves forward through the water with some velocity V.The effect of this forward motion is to generate dynamic pressures on the hull which modify the original normal static pressure and if the forces arising from this modified pressure system are resolved in the fore and aft direction it will be found that there is now a resultant which opposes the motion of the ship through the water.If the forces are resolved in the transverse direction the resultant is zero because of the symmetry of the ship form.置于静水中的船舶经受着静水压力，它垂直作用于船体的浸湿表面。早已经说过，在处理浮力和稳性问题时，这些压力产生的力有一个垂向合力，它与作用在船舶质量的重力刚好相等，也即等于船舶的重量。如果将静水压力产生的力沿着首尾和横向分解，结果会发现合力在这两个方向上都为0。考虑一下船舶以某一速度V在水中前进时会发生什么。这一向前运动的结果是将在船体上产生动态压力，这种动态压力改变了原来的静态正压力；如果将改变后的压力系统所产生的力在船的前后方向进行分解，那么可以发现这时有一个合力，它与船在水中运动的方向相反。如果这些力沿横向分解，因船体形状的对称性合力为0。

Another set of forces has to be considered when the ship has ahead motion.All fluids possess to greater or less extent the property known as viscosity and therefore when a surface such as the immersed surface of a ship moves through water, tangential forces are generated which when summed up produce a resultant opposing the motion of the ship.The two sets of forces both normal and tangential produce resultants with act in a direction opposite to the direction in which the ship is moving.This total force is the resistance of the ship or what is sometimes called the “drag”.It is sometimes convenient to split up the total resistance into a number of components and assign various names to them.However, whatever names they are given the resistance components concerned must arise from one of the two types of force discussed, i.e., either forces normal to the hull surface or forces tangential to that surface.船舶向前运动时还要考虑另一组力。所有流体或多或少有一性质叫粘性，因此当如船体浸湿表面那样表面在水中前进时就产生了切向力，将其累加起来便产生了与船舶运动反向的合力。这两组垂向和切向的力产生的合力其方向与船舶运动的方向相反。这一总力就是船舶的阻力或有时叫做“拖力”。有时为了方便将总阻力分成许多分量并给予不同的名称。然而不管给什么名称，有关的阻力分量必定来自讨论过的两种力，即与船体表面不是垂直就是相切的力。

The ship actually moves at the same time through two fluids of widely different densities.While the lower part of the hull is moving through water the upper part is moving through air.Air, like water, also possesses viscosity so that the above water portion of a ship‟s hull is subjected to the same two types of forces as the underwater portion.Because, however, the density of air is very much smaller than water the resistance arising from this cause is also very much less in still air conditions.However, should the ship be moving head on into a wind, for example, then the air resistance could be very much greater than for the still air condition.This type of resistance is, therefore, only a limited extent dependent on the ship speed and will be very much dependent on the wind speed.实际上船舶同时在两种密度极其不同的流体中移动。当船体下部在水中移动时，其上部在空气中移动。空气如水一样也具有粘性，因此船体水上部分与水下部分一样也经受着同样的两种力。然而，因为空气的密度比水小很多，这一原因引起的阻力在静水空气状态下也非常小。但是举例来说，假如船舶迎风行驶，那么空气阻力会比静止空气状态下大许多。因此，这种阻力程度有限，取决于船舶速度，也在很大程度上取决于风速。

Types of resistance 阻力类型

It was stated above that it is sometimes convenient to split up the total resistance into a number of components, these will now be considered.上面说过，有时为了方便将总阻力分为许多分量，现在来讨论这些分量。

The redistribution of normal pressure around the hull of the ship caused by the ahead motion gives rise to elevations and depressions of the free surface since this must be a surface of constant pressure.The result is that waves are generated on the surface of the water and spread away from the ship.Waves possess energy so that the waves made by the ship represent a loss of energy from the system.Looked at in another way the ship must do work upon the water to maintain the waves.For this reason the resistance opposing the motion of the ship due to this cause is called ”wave-making resistance”.With deeply submerged bodies the changes in the normal pressure around the hull due to ahead motion have only a small effect on the free surface so that the wave resistance tends to be small or negligible in such cases.船舶前进运动造成的船体周围正压力的重新分布引起自由液面的升起和降落，因为睡眠必须是常压表面。其结果是在水面产生了波浪并由船舶向外伸展。波浪具有能量，因此船舶造成的波浪代表了系统中能量的损失。从另一角度看，船舶必须对水做功以维持波浪。根据这一道理，由这个原因引起的抵抗船舶运动的阻力称作“兴波阻力”。对于深潜的物体由前进运动造成壳体周围正压力的变化对自由表面仅有细微影响，因而波浪阻力变得很小或在这种情况下可以忽略。

The resistance arising due to the viscosity of the water is appropriately called “viscosity resistance” or often “frictional resistance”.The thin layer of fluid actually in contact with the immersed surface is carried along with it but because of viscosity a shear force is generated which communicates some velocity to the adjacent layer.This layer is turn communicates velocity to the next layer further out from the hull and so on.It is clear then that there is a mass of fluid which is being dragged along with the ship due to viscosity and as this mass requires a force to set it in motion there is a drag on the ship which is the frictional resistance.The velocity of the forward moving water declines in going outwards from the hull and although theoretically there would still be velocity at infinite distance the velocity gradient is greatest near the hull and at a short distance outwards the forward velocity is practically negligible.Forward velocity is therefore confined to a relatively narrow layer adjacent to the hull.This layer is called the “boundary layer”.The width of the layer is comparatively small at the bow of the ship but thickens in going aft.由于水的粘性引起阻力被确当地称为“粘性阻力”或通常叫做“摩擦阻力”。和浸湿表面实际接触的一薄层流体被表面夹带，但因为粘性而产生了剪力，剪力将一部分速度传给临近的薄层。这一薄层又将速度传给下一离船体更远的薄层，等等。那么很清楚有一定质量的流体因粘性被船体拖者走；因为这一质量要求外力使其运动，船舶就有阻力，叫做摩擦阻力。由船体向外，水向前运动的速度下降；尽管从理论上讲在无限远处水还有速度，速度梯度在靠近船体处最大而在一个短距离之外前进速度实际上可以忽略。因此前进速度仅限于船体附近相对很窄的一层。这一层称作“边界层”。这一层的宽度在船首相比较小，但往后会加厚。

The actual thickness of the boundary layer is indeterminate but the point where the forward velocity has fallen to about 1% of what it would be if the water were frictionless is considered to be the outer extremity of the boundary layer.Thus, where the velocity of the water relative to the body is 0.99 of what it would be at the same point if the water were frictionless would be the outer edge of the boundary layer.边界层的实际厚度是不能确定的；但是，如果水没有摩擦力时边界层水将随船前进，那么水的前进速度下降了1%，这一处就被认为是边界层的外沿。于是水的某处相对于物体的速度为99%的同一点速度（假如水没有摩擦）时，该处就是边界层的外缘。

Theoretical investigations on flow around immersed bodies show that the flow follows the type of streamline pattern.However, where there are sharp changes of curvature on the surface of the body, and partly due to the viscosity of the fluid, the flow separates from the surface and eddies are formed.This separation means that the normal pressure of the fluid is not recovered as it would be according to theory and in consequence a resistance is generated which is often referred to as “eddy-making resistance”.This type of resistance, like wave-making resistance, arises from a redistribution of the normal pressure around the hull in contrast to the frictional resistance which arises because of tangential viscous forces.对沉浸物体周围水流的理论研究表明水流呈现流线形式。但是，在物体表面有曲度突变之处，部分是流体粘性缘故，水流从表面散开而形成旋涡。这样的散开意味着流体的正压力没有像理论那样会恢复，结果产生了阻力，它常被称为“旋涡阻力”。这一形式的阻力，像兴波阻力，是由船体周围的正压力重新分布而引起的；与摩擦阻力相左，它是因切向粘性力引起的。

The fourth type of resistance is that due to the motion of the above-water form through the air, as has already been mentioned, and could consist of a combination of frictional and eddy resistance.第四种阻力是船体水上部分在空气中运动引起的那种阻力，如早已提到的，可由摩擦阻力和旋涡阻力联合构成。

Part B（节选）

The Propulsion device 推进设备

The force needed to propel the ship must be obtained from a reaction against the air, water or land, e.g., by causing a stream of air or water to move in the opposite direction.The sailing ship uses air reaction.Devices acting on water are the paddle wheel, oar and screw propeller.Reaction on land is used by the punt pole or the horse towing a barge.推进船舶所需的力必须由空气、水或陆地的反作用力而获得，例如，靠产生气流或水流朝相反方向运动。帆船利用空气反作用力。作用于水的设备如明轮、橹和螺旋桨。陆地反作用力的利用靠撑船杆（蒿）或马匹拖驳船。

For general applications, the land reaction is not available and the naval architect must make use of water or air.The force acting on the ship arises from the rate of change of momentum induced in the fluid.对于一般应用，陆地反作用力不可利用，造船师必须利用水和空气。作用在船上的力来自流体中产生的动量变化率。

Consider a stream of fluid, density ρ, caused to move with velocity v in a “tube”, of cross-sectional area A.Then the mass of fluid passing any section per second = ρAv and the momentum of this fluid = mv = ρAv2.Since fluid is initially at rest, the rate of change of momentum =ρAv2.考虑一股流体，密度ρ，在截面积为A的“管子”里被驱动，速度为V。那么，在管子任何一段通过的流体质量 =ρAV且这一流体的动量= mv = ρAV。然流体初始为静

2止，那么动量变化率=ρAV2。

In a specific application, the force required is governed by the speed desired and the resistance of the ship.Since the force produced is directly proportional to the mass density of the fluid, it is reasonable to use the more massive of the two fluids available, i.e., water.If air were used, then either the cross-sectional are of the jet must be large or the velocity must be high.在特定的应用中，所需的力由希望达到的速度和船舶的阻力来决定。因为产生的力直接与流体的质量密度成比例，所以利用现成的两种流体中的更重者是合理的，就是利用水。假如使用空气，那么不是喷流的截面积必须很大，就是速度必须很高，两者取其一。

This explains why most ships employ a system by which water is caused to move aft relative to the ship.A variety of means is available for producing this stream of water aft, but by far the most commonly used is the screw propeller.这说明了为什么大多数船舶采用一种系统驱使水流朝船的后方运动。有各种各样的方法可用来产生这种向后的水流，但到目前为止最广泛使用的还是螺旋桨。

The screw propeller Basically the screw propeller may be regarded as part of a helicoidal surface which, in being rotated, “screws” its way through the water driving water aft and ship forward.Some propellers have adjustable blades – they are called controllable pitch propeller – but by far the greater majority of propellers have fixed blades.The ones we are concerned with here are fixed pitch propellers.基本上螺旋桨可以认为是螺旋面的一部分，当它旋转时（螺旋桨）一路往水里“拧”，将水往后推，而使船向前进。一些螺旋桨有可调节的叶片，它们称作可调螺距螺旋桨，但到目前为止大多数螺旋桨有固定的螺距。这里我们关心的是固定螺距螺旋桨。

Propellers can be designed to turn in either directions in producing an ahead thrust.If they turn clockwise when viewed from aft, they are said to be right-handed;if anticlockwise, they are said to be left-handed.In a twin screw ship, the starboard propeller is normally right-handed and the port propeller left-handed.They are said to be outward turning and this reduces cavitation.螺旋桨可以设计成在产生向前推力时朝两个方向旋转。从后面往前看，如果它们顺时针转，就称为右旋，如果逆时针转，就称为左旋。在双桨船上，右舷桨通常是右旋的而左旋桨是左旋的。这一对桨叫做外旋，这样可减少空蚀。

Considering each blade of the propeller, the face is the surface seen when viewed from aft, i.e., it is the driving surface when producing an ahead thrust.The other surface of the blade is called the back.The leading edge of the blade is that edge which thrusts through the water when producing ahead thrust and the other edge is termed the trailing edge.现在考虑螺旋桨的每片桨叶，叶面是从后面往前看时所见的表面，也即产生向前推力时的驱动面。叶片的另一面称作叶背。叶片的导边是在产生向前推力时挤进水里的那边，而另外一边叫做随边。

Other things being equal, the thrust developed by a propeller varies directly with the surface area, ignoring the boss itself.This area can be described in a number of ways.The developed blade area of the propeller is the sum of the face area of all the blades.The projected area is the projection of the blades on to a plane normal to the propeller axis, i.e., the shaft axis.其他方面相同。螺旋桨发出的推力直接随表面积而变，忽略轮毂自身。面积可以用许多方法来描述。螺旋桨的桨叶展开面积是全部桨叶叶面积的总和。投影面积是桨叶在垂直于螺旋桨轴线即轴中心线的平面上的投影。

Seakeeping qualities 耐波性

The general term seaworthiness must embrace all those aspects of a ship design which affect its ability to remain at sea in all conditions and to carry out its specified duty.It should, therefore, include consideration of strength, stability and endurance, besides those factors more directly influenced by waves.Here the term seakeeping is used to cover these more limited features, i.e.motions, speed and power in waves, wetness and slamming.适航性作为一般的术语必须包括船舶设计的下列方面，即对船舶在各种海况下保持漂浮能力的影响，对执行指定任务能力的影响。因此除了那些更直接受波浪影响的因素，适航性还应该包括的考虑因素有强度，稳性和续航力等。这里的术语耐波性用来涵盖这些更为局限的特性，即运动，波浪中的速度和功率浸湿性以及拍击。

The relative importance of these various aspects of performance in waves varies from design to design depending upon what the operators require of the ship, but the following general comments are applicable to most ships.这些不同方面的波浪性能的相对重要性因设计而异，取决于船者对船舶的要求如何，但是下列一般性评论对大多数船都适用。

Motions 运动

Excessive amplitudes of motion are undersirable.They can make shipboard tasks hazardous or even impossible, and reduce crew efficiency and passenger comfort.In warships, most weapon systems require their line of sight to remain fixed in space and to this end each system is provided with its own stabilizing system.Large motion amplitudes increase the power demands of such systems and may restrict the safe arcs of fire.过大幅度的运动是不希望的。这会给船上任务带来危险，甚至不可能完成任务，并且会减低船员效率和旅客的舒适性。在军舰上，大多数武备系统要求其视线在空间保持固定，并为此目的每一系统都配备了自己的稳定系统。大的运动幅度增加这类系统的功率需求并可能限制其可靠火力圈。

The phase relationships between various motions are also important.Generally, the phasing between motions is such as to lead to a point of minimum vertical movement about two-thirds of the length of the ship from the bow.In a passenger liner, this area would be used for the more important accommodation spaces.If it is desirable to reduce the vertical movement at a given point, then this can be achieved if the phasing can be changed, e.g.in a frigate motion at the flight deck can be the limiting factor in helicopter operations.Such actions must inevitably lead to increased movement at some other point.In the frigate, increased movement of the bow would result and wetness or slamming might then limit operations.各种运动间的相位关系也很重要。一般来说，运动的相位要导致一点的最小垂向运动，该点约在自船首起船长的三分之二处。在定期客船上，这一区域会被用于更重要的居住舱室。如果希望在给定一点减小垂向运动，那是可以办到的，只要相位能改变，例如在护卫舰上飞行甲板的运动可能是直升飞机操作的限制因素。这些作用不可避免地会导致其他一些点上的运动增加。在护卫舰上会导致船首运动增加，那么浸湿性和拍击可能限制军事行动。

Speed and power in waves 在波浪上的速度和功率

When moving through waves the resistance experienced by a ship is increased and, in general, high winds mean increased air resistance.These factors cause the ship speed to be reduced for a given power output, the reduction being aggravated by the less favourable conditions in which the propeller is working.Other unpleasant features of operating in waves such as motions, slamming and wetness are generally eased by a reduction in speed so that an additional speed reduction may be made voluntarily.在水中运动时，船舶经受的阻力会增加，而且一般说来疾风意味着增加空气阻力。这些因素使得船舶在给定功率输出的情况下航速下降，并且由于螺旋桨在较为不利的条件下工作，航速下降将加剧。其他在波浪中操作令人不适的特性加运动、拍击和浸湿性一般可由减速来减轻，因此，可能会自愿地额外减速。

Slamming 拍击

Under some conditions, the pressures exerted by the water on a ship‟s hull become very large and slamming occurs.Slamming is characterized by a sudden change in vertical acceleration of the ship followed by a vibration of the ship girder in its natural frequencies.The conditions leading to slamming are high relative velocity between ship and water, shallow draught and small rise of floor.The area between 10 and 25 percent of the length from the bow is the area most likely to suffer high pressure and to sustain damage.在某些条件下水对船体施加的压力变得非常大，而且会发生拍击。拍击的特征是船舶垂向加速度突然改变随后船体梁以其固有频率发生振动。导致拍击的条件是船舶与水之间很高的相对速度，此吃水和较小的舭部升高。自船首起10%~25%之间的船长区域是最容易承受高压和遭受破坏的区域。

Ship routing 船舶航线

Since the ship behaviour depends upon the wave conditions it meets, it is reasonable to question whether overall performance can be improved by avoiding the more severe waves.This possibility has been successfully pursued by some authorities.Data from weather ships are used to predict the speed loss in various ocean areas and to compute the optimum route.In this way, significant saving has been made in voyage times, e.g.of the order of 10~15 hours for the Atlantic crossing.既然船舶的性能表现取决于它所遇到的波浪状况，那么就有理由问：是否可以通过避免严厉的波浪来改善船的总体性能呢？这种可能性被一些权威机构成功地追究过。气象船提供的资料用来预测在各种海域的速度损失和计算最佳的航行路线。用这种方法，航行时间已经得到显著的节省，比如，横跨大西洋节省的时间量级在10至15个小时。

Importance of good seakeeping 良好耐波性的重要性

No single parameter can be used to define the seakeeping performance of a design.In a competitive world, a comfortable ship will attract more passengers than a ship with bad reputation.A ship with less power augment in waves will be able to maintain tighter schedules or will have a lower fuel bill.In extreme cases, the seakeeping qualities of a ship may determine its ability to make a given voyage at all.没有哪一个参数可用来定义船舶设计的耐波性。在这个充满竞争的世界里，一艘舒适的船会比一艘声誉不好的船吸引更多的旅客。一艘在波浪中航行时功率增额较少的船舶能够严格遵守较紧凑的时间表，或者支付较低的燃料帐单。在极端的情况下，一艘船舶的耐波性好坏可能会完全决定它执行一次给定航程的能力。

Good seakeeping is clearly desirable, but the difficulty lies in determining how far other design features must, or should, be compromised to improve seakeeping.This will depend upon each particular design, but it is essential that the designer has some means of judging the expected performance and the effect on the ship‟s overall effectiveness.Theory, model experiment and ship trial all have a part to play.Because of the random nature of the sea surface in which the ship operates, considerable use is made of the principles of statistical analysis.良好的耐波性显然是人们所希望的。但是困难在于确定其他设计特性必须或应该在多大程度上做出让步以改善耐波性。这应取决于每一个特定的设计，但有一点是必须的，即设计者应有一套方法来判定预期的性能及其对总体有效性的影响。理论研究、船模试验和船舶试航都是可行的方法。由于船舶航行的海面状况是随机性的，因此相当多的方法是采用数理统计分析原理。

Having improved the physical response characteristics of a ship in waves the overall effectiveness of a design may be further enhanced by judicious sitting of critical activities and by fitting control devices such as anti-roll stabilizers.已经改善了船舶在波浪中的实际响应特性，一艘船舶设计的总体效果可以通过慎重地确定重要作业的位置和安装诸如抗摇稳定器等控制设备来进一步提高。

As with so many other aspects of ship design a rigorous treatment of seakeeping is very complex and a number of simplifying assumptions are usually made.For instance, the ship is usually regarded responding to the waves as a rigid body when assessing motions and wetness although its true nature as an elastic body must be taken into account in a study of structure.In the same way it is instructive, although not correct, to study initially the response of a ship to regular long-crested waves ignoring the interactions between motions, e.g.when the ship is heaving the disturbing forces will generate a pitching motion.由于船舶设计要考虑众多其他方面，因而对耐波性的严格处理是非常复杂的，通常要作大量简化问题的假定。比如说，尽管在结构研究中船舶必须以其真实特性——弹性体来考虑，但当评价它在波浪中的运动和淹湿性时，船舶通常仍被认为是刚体来响应波浪的。同样地，最初研究对规则长峰波的响应时，忽略了运动间的相互作用，例如船舶升沉时，干扰力会产生纵摇运动；这种忽略虽然不正确，但却有指导意义。

Unit 3

Structural Strength Lecture 3

Translation of Emphatic Sentences 专业词汇学习

Ship Structural Members 1.On Deck Deck plating(DK pltg)甲板板；

Deck stringer

甲板边板 Cross strip

横向甲板条； Deck Girder

甲板纵桁 Beam

横梁；

Deck longitudinals 甲板纵骨 Hatch carling(carline)/ hatch side girder 舱口边桁 Hatch end beam 舱口端梁 Hatch coaming

舱口围板 2.On Sides Sheerstrake

舷顶列板 Sub – sheerstrake 次顶列板 Side shell

舷侧外板 Frame

肋骨 Deep frame

强肋骨 Side stringer

舷侧纵桁 3.In Bottom Space Inner bottom（IB）内底；

Outer bottom（OB）Plate keel

平板龙骨；

Duct keel

Bilge keel

舭龙骨；

Keel strake

Bilge strake

舭列板；

Keelson

Side girder

底部边纵桁；Bracket floor(Bkt Fl)Solide floor

实肋板；

Bottom longitudinals Docking bracket 坐坞肋板 4.On Bulkhead Longitudinal bulkhead(Long.Bhd)

纵舱壁 Transverse bulkhead

(Trans.Bhd)

横舱壁 Corrugated bulkhead

槽形舱壁 Deep tank bulkhead

深舱舱壁 Bulkhead plating

舱壁板 Vertical girder

垂桁 Horizontal girder

水平桁 Stiffener

扶强材 5.On Subassembly Face plate / rider 面板 / 顶板 Web plate

腹板 Bracket

肘板 Stiffener

扶强材 6.Materials Sections

型钢 Angle bar(Ang)角钢 Flat bar(FB)

扁钢 Bulb flat(BF)

球扁钢

Inequal angle(IA)不等边不等厚角钢 Plates

钢板 Sheet

薄板 Heavy plate

厚板 Steel Grades

钢级 Mild steel（MS）低碳钢

Higher tensile steel(HTS: H32 / H36)高强度钢 Ship Strength 船舶强度 1.Strength 强度

外底

箱形龙骨 K行板 肉龙骨 框架肋板 底部纵骨

Material 材料

Yield Strength

屈服强度 Tensile Strength

抗拉强度 Ultimate Strength 极限强度

Cyclic Strength

交变负荷强度 Permissible stress 许用应力 Ship Hull 船体

Bending strength 弯曲强度 Shearing strength 剪切强度 Torsional strength 抗扭强度 Buckling strength 翘曲强度 Fatigue strength

疲劳强度 2.Hull Girder 船体梁

Simple beam(simply supported beam)简支梁

Thin – walled box beam

薄壳箱形梁 Torsion box girder

抗扭箱形桁 Trochoidal wave

坦谷波 Longitudinal bending

纵总弯曲 Hogging

中拱 Sagging

中垂

Moment of area

静矩，面积矩 Neutral axis

中和轴

Section modelus at bottom

船底剖面模数 Hull moment of inertia

船体惯性矩 3.Forces 力

Deadweight 载重量 Buoyancy

浮力 Shearing force 剪力

Still – water bending moment(SWBM)

静水弯矩

Vertical wave bending moment(VWBM)垂向波浪弯矩 Cargo torque

货物扭矩

Wave induced torque 波浪扭矩 Structural Documents Rule scantlings calculations 船体构件规范计算书 Longitudinal strength calculations 总纵强度计算书

Hull steel list 船体钢料清单； Welding specification 焊接规格说明书 Booklet of details

节点图册 Basic structure arrangement 基本结构图

Profile 中纵剖面；

Upper deck 上甲板平面

Second deck(if any)二甲板平面；

Platform(if any)平台平面 Bottom 船底；

Superstructure plane 上层建筑平面 Shell expansion

外板展开图 Frame(body)plan

肋骨形线图 Bulkhead plan

舱壁结构图 Midship section plan

舯剖面结构图 Or Typical sections plan

典型横剖面图 Stern frame plan

尾框架结构图 Stern plan

首柱结构图 Aft end structure

尾部结构图 Fore end structure

首部结构图 Machinery space structure 机舱结构图 Cargo hold structure

货舱结构图 Deckhouse structure

甲板室结构图 Funnel structure

烟囱结构图 Bulwark structure

舷墙结构图 Bilge keel plan

舭龙骨结构图 Anchor recess structure

锚穴结构图 课文阅读 Part A It was stated that one of the requirements in the design of a ship was that the structure should be sufficiently strong to withstand without failure the forces imposed upon it when the ship is at sea.In this chapter the problem of structural strength will be studied in more details.曾经说过，船舶设计的要求之一是结构必须足够强以便承受船在海上时所遭受的各种力而不失效。在这一章中结构强度问题将予以更为详细的研究。

The problem consists first of all in assessing the forces acting on the ship and secondly in determining the response of the structure to those forces, i.e.in deformation of the structure.The structural strength problem is really a dynamic one.It has been seen that the ship is rarely in calm water and in consequence the motion of the sea generates motions in the ship itself.The motions generated because of the six degrees of freedom of the ship, i.e., heaving, swaying and surging, which are linear motions, and rolling, pitching and yawing, which are rotations, all involve accelerations which generate forces on the structure.It is also important to recognize that even in still water the ship is subjected to forces which distort the structure, the forces being due to hydrostatic pressure and the weight of the ship and all that it carries.A complete study of structural strength should take into account all these forces and in the present day development of subject that is in fact what is done.It is fitting, however, to examine the problem from the static point of view first of all.这一问题主要是，首先评估作用在船上的力，其次确定结构对这些力的响应，即结构的变形。结构强度问题实际上是一个动力学问题。已经看到，船舶很少处在平静的水中，结果海浪运动使船舶本身也产生运动。因船舶六个自由度而产生的运动，即垂荡、横荡和纵荡三个线性运动以及横摇、纵摇和首摇三个旋转运动，都涉及加速度，而加速度在结构上产生了力。同样重要的是应认识到即使在静水中船舶也受到力，它使结构变形，这些力是静水压力和船舶及所载物品的重力。完整的结构强度研究应该考虑到所有这些力；学科发展至今，实际上也是这样做的。然而，首先从静态的观点来讨论这一问题是合适的。

Static forces on ship in still water 静水中作用在船上的力

It has been seen that the hydrostatic forces on a floating body or ship in still water provide a vertical force B, say, which is exactly to the gravitational force acting on the mass M of the ship, i.e.Mg.Hence B = Mg.已经看到，在静水中作用到浮体或船舶的静水力提供了垂向力，比方说B，它和作用在船舶质量M上的重力即Mg恰好相等，因此B = Mg。

If the distribution of these forces along the length of the ship is examined it will be found that the gravitational force per unit length is not equal to the buoyancy per unit length at every point.If the mass per unit length at every point is m and the immersed cross-sectional area at the point is a then the net force per unit length is

ρga – mg 如果研究这些力沿船长的分布，则将发现在每一点上单位长度的重力和单位长度的浮力并不相等。如果每一点单位长度的质量为m而每一点浸湿横截面面积为a，则单位长度的净力是ρga – mg。

The ship under these circumstances carries a load of this magnitude which varies along the length and is therefore loaded like a beam.It follows that if this load is integrated along the length there will be a force tending to shear the structure so that

Shearing force = (gamg)dx

在这种情况下船舶携带这一大小随船长而变的负荷，因而就像一根加载的梁。于是，如果负荷沿长度积分，将有一个力倾向于剪切结构，因此

剪力 =

(gamg)dx

(gamg)dxdx On integration a second time the bending moment causing the ship to bend in a longitudinal vertical plane can be determined.Hence

Bending moment = 作第二次积分，可以确定造成船舶在纵向垂直平面内弯曲的弯矩，因此

弯矩 =

(gamg)dxdx

It will be seen that what is called longitudinal bending of the structure can be distinguished and this generates share and bending stresses in the material.将能看到，被称作结构纵向弯曲的情况可以分辨，这在船体材料中产生了剪切应力和弯曲应力。

Longitudinal bending is then a most important aspect of the strength of the structure of a ship and an accurate assessment of the longitudinal shearing force and bending moment is necessary in order to ensure safety of the structure.纵向弯曲是船舶结构强度最重要的一个方面，纵向剪力和弯矩的精确评定是必须的，以便确保结构的安全性。

The accurate determination of the still water shearing force and bending moment is a relatively easy task and while it does not give a complete picture of the longitudinal bending of the structure at sea it is most useful to calculate these quantities.High values of shearing force and bending moment in still water will usually indicate high values at sea, so that from still water calculations it is possible to obtain some idea of loading distribution which are likely to be undesirable.精确确定静水剪力和弯矩是相对容易的任务。虽然这种方法不能完善描述结构在海上的纵向弯曲，但计算这些数值还是非常有用的。在静水中剪力和弯矩的数值大，通常将预示在海上的数值也大，因此在静水计算中有可能获得载荷分布的一些概念，而这种分布可能是并不希望的。

The calculations of shearing and bending stresses in the material of the structure will be dealt with later.The other result arising from these forces and moments is that there is overall deflection of the structure, i.e.the ends of the ship move vertically relative to centre.When the ends move upwards relative to the centre the ship is said to “sag” and the deck is in compression while the bottom is in tension.If the reverse is the case then the ship “hogs” with the deck in tension and the bottom in compression.计算结构材料中的剪切应力和弯曲应力将在以后讨论。这些力和弯矩带来的其他结果是结构的总体桡曲，即船舶两端相对于中央的垂向运动。当两端相对于中央向上运动时，船舶被叫做中垂，其甲板处于压缩状态而底部处于拉伸状态。在倒过来的情况下，船舶被叫做中拱，其甲板处于拉伸状态而底部处于压缩状态。

The longitudinal bending of the ship due to static forces of weight and buoyancy has been dealt with above.These forces have other effects on the structure.This represents a transverse section through the ship and it will be seen that the hydrostatic pressure are tending to push the sides of the ship inwards and the bottom upwards.The weight of the structure and the cargo, etc., which is carried, are tending to pull the structure downwards.The result is that there must be material distributed in the transverse direction to resist this type of distortion.因重力和浮力两种静力引起的船舶纵向弯曲已在前面作了讨论。这些力对结构还有其他影响。这表现在船舶的横剖面；可以看到，静水压力倾向于将船侧向里推，将船底向上推。结构和所载货物等重量倾向于将结构向下压。结果是在横向方面必须分配材料来抵御这种形式的变形。

A third consequence of the forces acting upon the ship is local deformation of the structure.A typical example of this is the bending of plating between frames or longitudinals due to water pressure.Others are the bending of beams, longitudinals and girders under local loads such as those arising from cargo or pieces of machinery.力对船作用的第三个后果是结构的局部变形。这方面的一个典型例子如因水压力而致的肋骨或纵骨板间的弯曲。其他例子如横梁、纵骨和桁材在诸如货物或机器等局部载荷作用下的弯曲。

From the consideration of the forces acting upon the ship which have been discussed it is possible to distinguish three aspects of the strength of ship‟s structures.They are longitudinal strength, transverse strength and local strength.They are usually treated separately, although it is not strictly speaking correct since longitudinal and transverse bending are really interconnected.Considering, however, the complex nature of the problem of the strength of ship‟s structure it is a satisfactory approach, at least in the initial stages.已讨论过船上的作用力，由此考虑有可能区分船舶结构强度的三个方面。它们是纵向强度，横向强度和局部强度。这三种强度通常分别对待；诚然，严格地说这样做并不正确，因为纵向弯曲与横向弯曲实际上是相互联系的。但是，考虑到船舶结构强度问题的复杂性，这是一种令人满意的方法，至少在初始阶段是如此。

Function of the ship’s structure 船舶结构功能

The primary requirement of the ship‟s structure, i.e.that it should resist longitudinal bending, necessitates that a considerable amount of material should be distributed in the fore and aft direction.This “longitudinal” material as it may be called is provided by the plating of decks, sides and bottom shell and tank top, and any girders which extend over an appreciable portion of the length.The plating is thin relative to the principal dimensions of the transverse section of the structure and would buckle under compressive loads very easily if it was not stiffened.It is therefore necessary that there should be transverse stiffening of decks, shell and bottom, for this reason if for no other.The stiffening is provided in transversely framed ships by rings of material extending around the ship and spaced some 0.70~1 m(2~3 ft)apart.In the bottom the stiffening consists of vertical plates extending from the outer bottom to the inner bottom, the plates being called “floors”.The sides and decks are stiffened by rolled sections such as bulb angles or channels, called “side frames” and “beams”.The transverse material so provided has the dual function of maintaining the transverse form of the structure, i.e.providing transverse strength, and preventing buckling of the longitudinal material.船舶结构的基本要求，即它应该抵抗纵向弯曲，迫使相当数量的材料应该布置在纵向。这种材料可以称为“纵向”材料，由板材和各种桁材构成；板材如甲板板、舷侧与底部外板以及内底板，桁材应在船长方向延伸相当大的范围。与结构横向剖面的主要尺寸相比，板列的厚度很薄，假如不作加强，在压缩载荷的作用下可能很容易翘曲（失稳）。因此甲板、舷侧和船底该有横向加强是必要的，如果不为其他原因也是为上述原因。在横骨架式船上，这种加强由围绕船体伸展的材料框架提供，框架间隔0.70~1 m(2~3 ft)。在船底，加强构件由从外底伸至内底的垂直板件组成，该板叫做“肋板”。舷侧和甲板由轧制型钢如球扁钢或槽钢加强，它们称作“舷侧肋骨”和“横梁”。这样提供的横向材料具有维持结构横向形状的双重功能，即提供横向强度和防止纵向材料翘曲。

The spacing of the transverse material in relation to the plating thickness is an important factor both in resisting compressive stresses and in preventing local deformation due to water pressure, so that the span thickness ratio S/t cannot be allowed to be too great.Where thin plating is employed, as would be the case in small ships, the span S between the floors, frames and beams would have to be small but may be greater in large ships where thicker plating is employed.This will be found to be general practice, the frame spacing in small ships being less than in large ships.与板列厚度有关的横向材料间距是一个重要因素，原因在于一方面要抵抗压缩应力，另一方面要防止由水压力引起的局部变形，因此跨距厚度比S/t不允许大。在使用薄板的地方，例如在小船上，肋板间、肋骨间和横梁间的跨距必然较小，但在大船上使用较厚板列时跨距可以大一点。可以发现这是一般的习惯，小船上的肋骨间距比大船上的小。

Additional longitudinal strength is provided by longitudinal girders in the bottom of the ship.The centre girder is an important member in this respect.It is a continuous plate running all fore and aft and extending from the outer bottom to the tank top.Side girders are also fitted, and they are usually intercostals, i.e.cut at each floor and welded to them.The number of side girder depends upon the breadth of the ship.The double bottom egg box type of construction provided by the floors and longitudinal girders is very strong and capable of taking heavy loads such as might arise in docking and emergencies in going aground.额外的纵向强度由位于船舶底部的纵向桁材提供。在这方面中纵桁是一个重要构件。它是从船首通到船尾的连续板件并从外底伸至内底。也设置边纵桁，它们通常是间断的，即在每道肋板处切断并与之焊接。边纵桁的数量取决于船舶的宽度。双层底由肋版纳和纵桁构成的鸡蛋箱形式的结构是非常强的，能够承受重载荷，如在进坞时和搁浅紧急情况下引起的重载荷。

The practice of stiffening ships transversely has in recent years been largely replaced by a system of longitudinal framing.This method, which actually goes back a long way to such vessel as the Great Eastern, was initially adopted on a large scale in tanker and was known as Isherwood System.The system consists of stiffening decks, side and bottom by longitudinal members which may be either plate or rolled sections, the spacing being approximately of the same magnitude as beams, frames and floors in transversely framed ships.近几年来，横向加强船的做法大部分已被纵骨架式所取代。这一方法实际上可追溯到很久以前像“大东方”号那样的船舶，起初大规模用在油船上，并称为伊舍伍德纵骨架式。这一骨架形式的组成是：用纵向构件加强的甲板、舷侧和底部，构件可以是板件或轧制型钢件，间距与横骨架式船的横梁、肋骨和肋板的数值大致相同。

The longitudinals are supported by deep, widely spaced transverse consisting of plates with face flanges, the spacing being of the order of 3~4 m(10~12 ft).These transverses provide the transverse strength for the structure.Additional transverse strength is provided on all ships by watertight or oiltight bulkheads.These are transverse sheets of stiffened plate extending from one side of the ship to the other.Their main purpose is of course to divide the ship into the watertight or oiltight compartments so as to limit flooding of the ship in the event of damage, but they have the additional function of providing transverse strength.纵骨由大间隔强横桁支撑，横桁由腹板和面板组成，间距在3~4 m(10~12 ft)量级。这些横桁为结构提供横向强度。在所有船上，额外的横向强度由水密或油密舱壁提供。舱壁是横向的加强板列薄片，从船的一舷延伸到另一舷。当然，它们的主要目的是要将船舶分隔成水密或油密的舱室，以便船舶一旦损坏时来限制淹水范围，但它们有额外的功能就是提供横向强度。

The original Isherwood System was applied to oil tanker but was not favoured in dry cargo ships, largely because of the restriction in cargo space created by the deep transverses.With the large scale development of welding in ships, however, resulting in greater distortion of the plating than would normally be found in riveted construction, longitudinal stiffening in the bottom and deck has become quite common in these vessels, while the side structure is framed transversely as formerly.It will be found that this “combined” system of construction is now almost universally adopted in dry cargo ships.As a matter of fact the combined system was used for a time in oil tankers, but with their increasing size in the years since 1954 the complete longitudinal system has been reverted to.原先的伊舍伍德纵骨架式应用于油船但并不有益于干货船，主要是因为强横桁造成货舱空间的限制。然而随着造船焊接技术大规模发展，结果板列中出现了比铆接结构中通常能发现的更大的变形；这些焊接船的底部和甲板采用纵向加强方法变得十分普遍，但舷侧结构仍同以前一样作横向加强。可以发现，这种“混合骨架式”在干货船上现在几乎被普遍地采用。事实上，混合骨架式曾在一个时期内用于油轮；但是自从1954年以来油轮尺度越来越大，于是已经恢复采用全纵骨架式结构。

Two of the advantage of the longitudinal system are that the longitudinals themselves take part in the longitudinal strength of the ship and it can be shown also that the buckling strength of the plating between longitudinals is nearly four times as great as the strength of the plating between transverse stiffeners of the same spacing.纵骨架式的两个优点是：纵骨本身参加船体纵强度；也能说明，纵骨间板列的翘曲强度为同间距横向加强筋间板列强度的四倍之大。

When the decks of a ship are stiffened by transverse beams, if these were supported only at the two sides of the ship without any intermediate support, they would be required to be of very heavy scantlings, i.e.dimensions, to carry the loads.By introducing pillars at intermediate positions the span of the beams is reduced with the result that they can be made of lighter scantlings, thus providing a more efficient structure from the strength / weight point of view.Pillars were formerly closely spaced, being fitted on alternate beams with angle runners under the deck to transmit the load to the beams not supported by pillars.This meant that pillars were spaced about 1.5 m(5 ft)apart so that access to the sides of holds was very restricted.For this reason heavy longitudinal deck girders were introduced which had the same function as a line of pillars, the girders being supported by widely spaced pillars.Thus, in a cargo hold there would be two deck girders supported by two heavy pillars at the hatch corners.In this way access to the sides of the holds was improved.船的甲板用横梁加强时，假如这些横梁仅在船舶的两舷作支撑而没有中间撑，那么它们要求具有很大的构件尺寸，即尺度，以承受甲板载荷。在中间位置引入支柱后横梁的跨距减小了，结果是它们可用较小的构件尺寸来制造；于是从强度/重量比的角度来看这样提供了更有效的结构。以前支柱间隔很小，每隔一档横梁安装，并在甲板下面设置角钢短梁以传递没有支柱支撑处横梁的载荷。这意味着支柱的间隔约1.5 m(5 ft)，因此至货舱舷侧的通道很受限制。由于这个原因引入了大型甲板纵桁，它与一行支柱有相同的功能；该纵桁由隔得很远的支柱支撑。因此，在一个货舱内会有两道甲板纵桁，每一纵桁由舱口角隅处的大型支柱作支撑。这样至货舱舷侧的通道得到了改善。

Even these widely spaced pillars can be eliminated by fitting heavy transverses hatch end beams to support the longitudinal girders, the hatch end beams themselves being supported by longitudinal centre line bulkheads clear of the hatchways.通过安装大型舱口端梁来支撑纵桁，甚至可以把这些大间距的支柱省掉，而舱口端梁本身由在舱口范围以外的中纵舱壁来支撑。

In ships in which the longitudinal system of framing is adopted the deep transverse take the place of the longitudinal girders and give intermediate support to the longitudinals, thus reducing their scantlings.在采用纵骨架式的船上，强横桁代替甲板纵骨以中间支撑，因此可减小纵骨的尺寸。

Nearly every part of the structure of a ship has some local strength function to fulfil.For example, the bottom and side shell plating has to resist water pressure in addition to providing overall longitudinal strength of the structure.Thus, local stresses can arise due to the bending of the plating between frames or floors.The complete state of tress in such part of the structure is very complex because of the various functions which they have to fulfil, and even if the actual loading was known accurately it would be a difficult task to calculate the exact value of the stress.几乎每一船体结构都有一些局部强度功能要完成。例如，底部和舷侧外板除了提供结构的总纵强度之外还必须抵抗水压力。因此，由于肋板或肋骨间的板列弯曲可能会引起局部应力。结构在这些部位完整的应力状态是非常复杂的，因为它们必须完成各种功能；并且即使实际载荷已确切知道，要计算该应力的精神值也会是一项艰巨的任务。

Part B（节选）

Forces on a ship at sea 船舶在海上行驶的力

When a ship is moving through a seaway the forces acting on the ship are very different to those in still water.In the first place the static buoyancy is altered because the immersion of the ship at any point is increased or decreased compared with the still water immersion because of the presence of the waves.Secondly it has been seen that the pressure in a wave differs from the normal static pressure at any depth below the free surface.The ship also has motions which cause dynamic forces due to the accelerations involved.The two major effects are due to heaving and pitching.当船舶在海上航行时，作用在船上的力与在静水中时大不相同。首先，与静水状态下的浸深相比，由于波浪的存在船舶在每一点的浸深或增加或减少，因此静态浮力被改变。其次，已经看到，在自由表面下任何深度处，波浪中的压力与正常的静水压力不同。船舶还有运动，因涉及加速度而引起动态力。这两个主要影响是来自升沉和纵摇。

As stated above, the problem then becomes a dynamic one.The traditional practice has, however, been to reduce this dynamic problem to what is considered to be an equivalent static one.The procedure adopted was to imagine that the ship was poised statically on a wave and work out the shearing force and bending moments for this condition.Until relatively recently it was the procedure adopted in determining the longitudinal bending moments acting upon the ship at sea.如前所述，问题变成动态的了。然而传统做法已将这一动态问题简化为被认为是相当的静态问题。采取的步骤是先设想船舶静态地在波浪上保持平衡，然后计算出这一条件下的剪力和弯矩。直到最近这仍然是确定船在波浪上所受纵向弯矩的方法。

The static longitudinal strength calculation 在静态的纵向强度计算

In this calculation the wave upon which the ship is assumed to be poised statically is considered to be of trochoidal form and to have a length equal to the length of the ship.The height of the wave chosen for the calculation greatly affects the buoyancy distribution and this at one time was taken as the ship length divided by 20, i.e.h = L/20.More recently, however, a height given by h=0.607√L m(h=1.1√L ft)has been used in the calculation.This was considered to represent more closely the proportions of height to length in actual sea waves.在计算中，假定与船舶静态平衡的波浪被认为是次摆线型（坦谷）波，其长度等于船长。计算所选的波高会严重地影响浮力分布：波高曾一度取为船长除以20，即h = L/20。然而最近由公式h=0.607√L m(h=1.1√L ft)给出的波高已用于计算。这被认为更接近地代表了实际海浪的高度与长度之比。

Two conditions were usually examined;one with wave crests at the ends of the ship and one with a wave crest at amidships.In the former condition the bending moment due to the buoyancy provided by the wave produced sagging, and in the latter case hogging was produced.Associated with these two positions of the wave it was customary to assume loading conditions for the ship which would give the greatest bending moment.Thus, with the wave crests at the ends a concentration of loading amidships would yield the greatest sagging moment, while with a crest amidships concentration of load at the ends would give the greatest hogging moment.This could possible lead to some unrealistic conditions of loading for the ship.It is more satisfactory to consider the actual condition in which the ship is likely to be in service and to work out the bending moments for the two positions of the wave.In this way it is possible to determine for any given loading condition the cycle of bending moment through which the ship would go as a wave of any particular dimensions passes the ship.通常要讨论两种状态，一是波峰在船舶两端，一是波峰在船中。在前一状态下，由波浪提供的浮力所生成的弯矩产生中垂，而在后一状态下则产生中拱。结合这两种波浪位置，习惯上再假设船舶的装载情况，即会给出最大弯矩的装载情况。于是，波峰在两端而集中载荷在船中会产生最大的中垂弯矩；波峰在船中而集中载荷在两端会给出最大的中拱弯矩。这可能导致船舶一些不切实际的载荷状态。更令人满意的是考虑船舶在营运中容易出现的实际装载状态，并计算出这两种波浪位置时的弯矩。这样，对于任何给定的装载状态，都可以确定具有特定参数的波浪通过船舶时船体所承受的弯矩的循环周期。

In the procedure described the total bending moment is obtained, including the still water moment.It is often desirable to obtain these moments these separately so that the influence of the still water moment on the total can be examined.The wave moment depends only on the size of wave chosen and the ship form for any condition of loading, whereas the still water moment is dependent on the load distribution as well as the still water buoyancy distribution.在上述过程中，可获得总弯矩，包括静水弯矩。通常希望能分开获得这些弯矩，以便能研究静水弯矩对总弯矩的影响。波浪弯矩仅取决于所选波浪的尺度和任何装载状态下的船体形状，而静水弯矩取决于载荷分布和静水浮力分布。

The first step in the calculation is to balance the ship on the wave, which means working out the total mass M of the ship and the longitudinal position of its centre of gravity G.The problem then is to adjust the wave on the ship to give a buoyancy equal to Mg and a position of the centre of buoyancy which is vertically below G.In doing this it is usual to ignore the Smith effect.计算的第一步是让船舶在波浪上平衡，这意味着计算出船舶的总质量M和其重心纵向位置G。然后的问题是船上调整波浪以便给出浮力等于Mg，并且使浮心位置垂直地在G的下向方。这样做时通常忽略史密斯效应（水波质点运动对船体浮力的影响）。

To find the correct position of the wave is not an easy task since the free surface is a curve and not a straight line as in the still water position.Methods have been developed but will not be dealt with here.It will be supposed that this has been achieved, in which case the ship will be in static equilibrium under the gravitational force acting on the mass of the ship and the buoyancy provided by the wave.要找出波浪的正确位置不是一件容易的事，因为自由表面是曲线而不像在静水位置时的一条直线。方法已经开发出来，但在这里不予讨论。这里假定这一步已经达到，在这种情况下，船舶在由质量产生的重力与波浪产生的浮力的共同作用下处于静力平衡状态。

The next step in the calculation is to find the distribution of buoyancy and mass along the length of the ship.The former is easy since the buoyancy per unit length is simply ρgA, where A is the immersed cross--sectional area at any point in the length.The distribution of mass involves calculating the mass per unit length at a number of positions along the length and this is a tedious calculation requiring accurate estimates of the mass of the various part of the ship.The calculation is facilitated to some extent by dividing the total mass into the lightmass of the ship and the masses of the deadweight items.The details of these calculations will not be entered into here.计算的下一步是要找出浮力分布和质量沿船长的分布。前者容易，因为单位长度的浮力只是ρgA，式中A为船长任一点上浸湿横截面面积。质量分布涉及船长许多位置上单位长度质量的计算，然而这是一个枯燥的计算过程，要求精确地估算船舶各部分质量。将总质量划分为空船质量和各个载重量项目的质量，在某种程度上可以方便计算过程。这些计算的细节不在这里展开了。

Having obtained the distribution of buoyancy and mass, which in simplified form would look like the curves, it is possible to plot a load curve which is simply the difference between weight and buoyancy as in the still water calculation, i.e.Load per unit length = ρgA-mg From which the shearing force and bending moment are given by

F(gAmg)dx M(gAmg)dxdx

已经得出浮力和质量分布，其简化形式看起来像曲线，就有可能绘制负荷线，它只是重量和浮力之差，如在静水中的计算一样，即

单位长度负荷 =ρgA-mg 由上式，剪力和弯矩可由下列公式给出

F(gAmg)dx M(gAmg)dxdx

Because of the non-mathematical nature of load curve these integrations have to be done graphically or can be carried out by an instrument called “integraph”.In recent years, largely because of the development of the computer, a tabular method has been developed.It consists of dividing the length of the ship up into a number of equal parts(say 40)each of length l, and calculating the mean buoyancy per unit length b and the mean weight per unit length w in each of these divisions.It then follows that

Shearing force F(bw)ll(bw)

If then the mean value of the shearing force in each of these division is Fm then

Bending moment BMlFm

This procedure can be readily programmed for the computer and the shearing force and bending moment obtained very easily.因为负荷曲线的非数学属性，这些积分必须作图求得，或用称为“积分仪”的仪器来计算。主要是因为计算机的发展，近年来已开发了一种表格方法。它包括：将船舶长度分成许多相等的部分（比如40份），每一长度为L，并且在这些区间计算单位长度的平均浮力B和单位长度的平均重量W。于是

剪力F(bw)ll(bw)如果这些区间的剪力平均值为Fm，那么 弯矩BMlFm

这一过程可以容易地编写为计算机程序，因此剪力和弯矩很容易得到。

Characteristics of shearing force and bending moment curves 剪力曲线和弯矩曲线特性

The shearing force and bending moment curves for a ship poised on a wave are shown graphically and for most ships the curves follow this pattern.Both shearing force and bending moment are zero at the ends of the ship.The shearing force rises to a maximum value at a point which is roughly one quarter of the length from the end then falls to zero near amidships and changes sign, reaching a maximum value somewhere near a quarter – length from the bow.The bending moment curve rises to its maximum value at or near amidships, the exact positions occurring where the shearing force is zero.船舶在波浪上平衡时的剪力和弯矩曲线可以图示，并且大多数船舶的曲线都呈现这种模式。剪力和弯矩两者在船舶的两端都为0。大约在距船尾1/4 船长处剪力升到最大值，然后在靠近船中处降为0，并改变符号，又在距船1/4 船长的某处达到最大值。弯矩曲线在船中或靠近船中处升到最大值，确切的位置出现在剪力为0的一点。

The influence of the still water bending moment on the total moment can be seen from the curves.For a ship of any given total mass and the draught in still water the wave sagging and hogging moments are constant so that if the still water moment is varied by varying the loading the total moment may be altered considerably.The aim should be to keep the total as small as possible.If the wave sagging and hogging moments were equal then the smallest total moment would be obtained with a zero still moment.However, the wave sagging moment is usually greater than the wave hogging moment, the proportion depending amongst other factors upon the block coefficient.从曲线可以看出静水弯矩对总弯矩的影响。对于给定重量的船和给定静水吃水，波浪中垂和中拱附加弯矩是一定值。所以，如果由载荷变化而引起静水弯矩变化，那么总纵弯矩也可能发生很大的变化。目的是应该保持总弯矩尽可能地小。假如波浪中垂和中拱弯矩相等，那么将会得出最小的总弯矩而静水弯矩为0。然而波浪中垂弯矩通常比波浪中拱弯矩大。两者的比例取决于其他因素中的一个，即方形系数。