关于船舶与海洋工程结构极限强度的分析（共5篇）

第一篇：关于船舶与海洋工程结构极限强度的分析

关于船舶与海洋工程结构极限强度的分析

摘 要：在航运业的不断发展下，船舶的数量随之增多。海上发生的事故很多是因船舶搁浅造成的。当船舶发生事故后，其结构强度会受到影响，由此带来严重的后果。目前，我国对船舶与海洋工程结构极限强度的研究还不够，而结构极限强度是船舶与海洋工程结构理性设计中最后一个关键环节，需要进一步研究。

关键词：船舶；海洋工程；结构极限强度；结构损伤

中图分类号：U661.43 文献标识码：A DOI：10.15913/j.cnki.kjycx.2016.09.083

船舶与海洋工程结构极限强度的计算极其复杂，需要靠建立适当的船体模型来实现。通常采用对船体模块进行有限元分析的方法来计算，但这种计算方法在实际运用中存在一定的局限性。本文主要探讨了在船舶与海洋工程中结构强度方面需要注意的问题，以进一步分析极限强度，为海洋工程工作人员在这方面的研究提供帮助。结构极限强度计算方法

在船舶与海洋工程的结构理性设计中，结构极限强度的计算和分析是要求最高也最为复杂的环节。在实际中，通常利用对船体模型进行有限元分析的方法测量船体模型的构件屈曲和塑形变形等数据，从而得出比较精确的船体模型极限强度。然而，这种方法在实际运用中工作量很大，且成本很高，因此，推广程度不高。当前，一种叫作“逐步破坏法”的计算方法则较为常用。该方法不仅可以减少计算工作量，还可以提高极限强度计算结果的精确性。在船舶与海洋工程结构极限强度的计算上，逐步破坏法主要具有以下两方面的优点：①将用于结构极限强度计算与分析的船体模块向横向崩溃和纵向崩溃这两种独立的总崩溃模式转化；②通过限制相关尺寸，确保相邻的两个横向刚架纵向崩溃。逐步破坏法能够让船舶与海洋工程的船体模型横向刚架的临界分段在中垂或中拱过程中崩溃，将结构极限强度计算向船体某一分段极限纵强度计算简化，不仅能确保计算结果的精确性，还能大大减少计算工作量。极限强度的分析计算

在提出船体结构总纵极限强度的概念之后，对船体梁总纵极限强度分析有了越来越多的方法，主要有逐步破坏分析法、直接计算法和有限元法。

2.1 逐步破坏分析法

通过分析船体结构破坏机理，发现船体结构的整体破坏实际上是一个逐步破坏的过程。基于平断面假设，构件逐步破坏的增量曲率法，总结出可以利用横剖面纤维的应力-应变关系描述由屈曲和屈服引起的加筋板逐步破坏，并将后屈曲效应纳入考虑范围。Smith通过非线性有限元对单元弹塑性大挠度分析来获得单元平均应力-平均应变关系。这种方法的计算精度是由单元平均应力-平均应变关系的准确性决定的。

2.2 直接计算法

Caldwell根据船体横剖面的全塑性弯矩对船体总纵极限强度进行了估算，利用受压构件承载能力的折减来解释结构屈曲的影响。这种方法没有考虑当加筋板单元承受的压应力超过其极限强度后的载荷缩短行为和截面应力的重新分布，因此对船体结构总纵极限强度值的估算一般过高。

2.3 有限元法

有限元法对任何加载类型与结构模型都适用。引入平板单元、梁单元以及正交各向异性板单元，不仅能够分析结构在静态和动态载荷作用下的极限状态，还能够对单个结构作整体响应分析，并且将船体在扭矩、弯矩以及剪力联合作用下的响应纳入考虑范围。Kutt等利用这种方法计算和分析了4条船体按各种载荷状态、不同的有限元模型的纵向极限强度，并在分析过程中考虑了屈曲、后屈曲及塑性效应。船舶搁浅结构损伤分析

3.1 船底肋板和扶强材的变形损伤

按照极限强度解析计算方法的假定，可以发现船舶的纵向构件决定了其极限强度，因此，不需要过多地考虑船舶底部肋板和肋板上的扶强材的损伤变形，只需要关注它们在变形过程中的能量耗散。肋板的变形分为中间和两边两个部分。肋板中间部分受到礁石的直接作用而发生变形，两边部分也会受到波及而变形。船舶总的变形能可通过这两部分变形能Efloor，central、Efloor，side叠加得到，而肋板扶强材的变形能Efs主要通过膜拉伸变形和塑性弯曲两种形式耗散。

3.2 船舶外底板和纵骨的变形损伤

在船舶发生搁浅事故时，外底板纵骨的高度一般比礁石的撞击深度要小，在礁石的冲击挤压下，纵骨受到直接作用达到完全塑形状态，因而在船舶的极限强度中不发挥作用。由于纵骨失效，在解析计算过程中受损的船底外板也由原来的若干个纵向加筋板单元转化为一块横向板单元。

3.3 船底纵桁和加强筋的变形损伤

船底纵桁垂向与内外底板相连接并起到支撑作用。当船舶发生搁浅事故时，船底纵桁受挤压变形。通过“实际撞深下纵桁的变形能和垂直压缩距离等于双层底高度时纵桁的最大变形能的比值”来确定纵桁的损伤情况。载荷响应预报和极限强度解析预报

在分析船舶结构时，需要确定作用在船体上的载荷。因为载荷计算在很大程度上决定了结构分析的精度。通常，船体上的波浪载荷分为总体载荷和局部载荷，其中，总体载荷指的是局部海水动压力的合力。另外，波浪还会引起冲击力、甲板上浪的水压力以及舱内液体晃荡力等载荷。总的来说，分析波浪载荷对船体的极限强度计算有着很关键的作用。

在船体极限强度解析预报中，首先要将船体的横剖面划分为若干个小单元，其中，纵向加筋板单元是由一块板和一根纵向加强筋构成，横向加筋板单元一般情况下只有一块板，硬角单元通常是由两块不共面的板构成。将各个单元划分好以后，利用CSR规范公式得出各个单元的应力-应变关系。结束语

出于对船舶安全性的考虑，要对船舶与海洋工程结构极限强度进行进一步的分析。运用逐步破坏法分析船舶在搁浅时的损伤，并对极限强度进行解析预报，从而加强对船体结构的设计。

参考文献

[1]于海洋，张世联，乔迟，等.关于箱型梁结构提高舰船舱内爆炸后剩余纵向极限强度的可靠性评估[J].船舶力学，2014（03）：318-326.[2]李恒，郎元荣.船舶与海洋工程结构极限强度分析[J].科技资讯，2015（07）：68.[3]丁超，赵耀.船舶总纵极限强度后剩余承载能力有限元仿真方法研究[J].中国造船，2014（01）：54-64.〔编辑：刘晓芳〕

第二篇：船舶结构强度分析

船舶结构强度分析

近几年来，国内船舶修理公司如雨后春笋般出现，修理任务急剧扩张，修理的船型也是多种多样，涵盖整个船舶市场。而对船体结构的修理也是首当其冲，由于船厂的技术水平和工人技能等多方面原因，对于结构修理过程中拆换结构也会出现不同的修理方案，导致船舶结构在修理后出现异常情况。因此对于船舶结构强度分析的提出是相当重要的。其主导思想是在船舶修理的船体拆换强度分析的应用中，运用的基本计算原理和方法，是以船舶原理和船舶结构力学为理论基础。在以往的工程实际中，修船工程技术人员往往忽略或者不重视将这些理论的知识与船舶修理工程充分地结合起来。为了很好地说明这些基础理论在修船工程实际中的应用，本文将以船舶原理和船舶结构力学的基本理论，来阐述在船舶修理工程中的基本强度理论和基本计算原理及方法。

一、船舶结构力学

在船舶工程传统意义上，船舶结构力学研究和解决船体结构在静力响应，即在给定的外力作用下如何确定船体结构（局部和整体）中的应力、变形情况。在船舶修理工程中，因船舶在设计建造时已经对船舶的强度进行了计算和设计，所以要解决的问题就是强度计算，概括来讲，就是在船体结构尺寸已知的条件下，在给定的外载荷或工况下，计算出结构的应力和变形，并与许用值比较，从而判断船体结构的强度是否足够。船体结构强度的计算是依据船舶原理的基本设计理念，运用理论力学和材料力学的力学基本理论来对船舶的结构强度进行计算和校核的。

二、力学模型和船体模型

在船舶修理工程中的结构强度计算中，为了便于计算，须对实际的结构进行简化，在简化模型的基础上，施加外载荷，再运用船舶结构力学的基本理论和方法来计算船体结构的应力和变形情况。为了满足计算的需要，可以将在船舶修理工程实际情况下的船体结构的简化模型分成两个类型，一是基于传统船舶结构力学基础上的“力学模型”，二是在便于现代计算机计算和有限元理论分析的“船体模块”，这两个类型有渐进的关系。

“力学模型”的建立是根据实际结构的受力特征、结构之间的相互影响以及对计算精度的要求等各个方面的因素来确定的。

在船舶修理工程中，船体“力学模型”的简化一般有以下几种形式：

一是船体中的受压或者拉压的板，可以把四周由纵横骨架支持的这种受压或者拉压的板看作具有矩形周界的平板模型。在甲板纵骨被局部割断后，在未断纵骨和框架之间的主甲板就可以简化成这样的模型，在舱口围横梁被拆断后，舱口围板就成为受压板结构了，同样可以简化成这一类的力学模型结构。

二是船体结构中解除部分约束条件的骨架可以看作力学中的“杆系系统”。连续梁、刚架和板架结构是“杆系系统”中典型的结构。因舷侧板需换新，在拆除后，相应位置的肋骨因支撑板约束的解除而成为受压杆件。至于船体的双层底结构，在实际的计算处理中一般可以简化为刚架和板架结构。

而“船体模块”是为了便于计算机的计算方便，将船体的结构进行离散处理，化成小的能够表达结构的所有特征的子结构。“船体模块”的确定既要考虑到该结构的几何形状，又要考虑其结构载荷的特点，同时又必须采取适合有限元方法的计算特点来进行。

三、强度分析与计算

与船舶设计建造中的结构强度计算一样，船舶修理实际的工程中，对船体结构的改变（拆装或新加），同样是应用力法、位移法、能量法和矩阵法等方法。但与船舶设计不同的是，船舶修理是在原有结构被拿掉后，产生新的外载荷和新的边界条件，这时要对新情况下的强度进行计算和校核，确定在新的外载荷和边界条件下的结构应力和变形。下面以某船的局部构件换新为例，来探讨力法、位移法、能量法和矩阵法在船舶修理工程中的应用。

以下为某散货船上边舱横剖面结构图，图示阴影部分因板腐蚀变薄须进行换新处理。

散货船上边舱局部挖换 TST Frame Partly Renewal

先将该拆换结构进行简化和模型化处理，如上图所示，可以简化成两端为固定端，甲板纵骨为支点的简支梁结构，考虑到甲板板的垂直压力，简支梁可以看成受垂直方向的均布载荷q的作用。下面就以这个模型为基础来介绍在船舶强度分析中常用的几种分析计算方法。

1、力法求解

这是结构力学中最基本和最常用的方法之一。它的基本原理是将静不定结构的多余约束去掉,代以约束反力,使其成为一静定结构；去掉约束出现约束反力的地方列变形连续方程式以保证基本结构的变形与原结构相同。方程式的数目与未知数数目相同。对于结构有n个未知力，则有n个变形连续方程式，可以列出“力法正则方程式”如下：

(1-1)

式中，δij为结构中力Xj在力Xi位置处的引起的应变，∆i为外力在力Xi位置处引起的位移；解变形连续方程式求出未知力，进一步可以求出结构的弯曲要素。对图中力学模型，根据式（1-1），且δij=δji，列出变形连续性方程组

:

(1-2)

式中，M0、M1、M2分别为节点0、1、2处的弯矩；l为单跨粱的长度：Q为单跨粱上的载荷。求解可得：

该结构的剪力图和弯矩图如下：

剪力和弯矩示意图

Bending Moment and Shear force Arrangement2、位移法求解

以节点转角为未知数（角位移），再根据节点断面弯矩平衡条件建立方程式。位移法的一般原理和解法步骤为:

分析结构的节点，找出可以转动的节点数；然后设想在可能发生转角的节点上加上抗转约束；再假想将加固的各节点强迫转动，使之发生转角，按照公式列出杆端弯矩；最后对发生转动的各节点建立节点弯矩平衡方程式；解弯矩平衡方程式，可求得各杆端弯矩和弯曲要素。

根据节点弯矩平衡方程式组：

（2-1）

Iij为杆ij的惯性矩 lij为杆ij的长度 θi为节点I处的转角

对图2-1列弯矩平衡方程式，有

(2-2)

可以求得：

3、能量法求解

能量法的基本原理是根据弹性体在外力的作用下将发生变形，载荷在相应的位移上做功，同时，弹性体因变形而产生应变能，列相应的能量方程式，从而求解变形方程式，进一步可以得出应力情况。弹性体的应变能为

根据位能最小原理：在满足几何关系和给定的位移边界条件的所有可能位移中，真实的位移使得系统的总位能取驻值，有：

取满足位移边界条件的挠曲函数，计算应变能、力函数以及总位能：

4、矩阵法求解

类似于有限元方法。为本文解决在船舶修理工程中的强度计算的重点应用方法。这里仅简述如何求解图示的问题。

总刚度矩阵为

端点力计算如下：

可以直接求解得到未知节点位移，进一步可求得内力分布

本文在充分吸收和运用现有的船舶原理和船舶结构力学理论的基础上，结合船舶修理工程的实际情况，对船舶修理工程中出现的需要解决的强度校核问题进行定性的分析，通过理论和实践相结合的方法，探讨船舶修理工程中的船体结构改变所引起的结构强度变化的理论计算方法，并将其方便和快捷地转化为实际的工程技术人员比较容易接受和使用的技术工艺方法。通过一定的实例来剖析船舶结构强度的理论计算方法，通过实例和理论相互阐释的方式，分析船舶强度校核理论在船舶修理实际中的应用，进而达到本文的研究目标。再现代修船业务中运用科学的理论和计算方法是可行而且必要的，同时也是未来发展船舶修理工工程所必须面对的。

第三篇：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。

第四篇：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

第五篇：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