Introduction to Naval Architecture 3E potx

Introduction to Naval Architecture

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Introduction to Naval

Architecture

Third Edition

E. C. Tupper, BSc, CEng, RCNC, FRINA, WhSch

OXFORD AMSTERDAM BOSTON LONDON NEW YORK PARIS

SAN DIEGO SAN FRANSISCO SINGAPORE SYNDEY TOKYO

Butterworth-Heinemann

An imprint of Elsevier Science

Linacre House, Jordan Hill, Oxford OX2 8DP

First published as Naval Architecture for Marine Engineers, 1975

Reprinted 1978, 1981

Second edition published as Muckle's Naval Architecture, 1987

Third edition 1996

Reprinted 1997, 1999, 2000, 2002, 2002

Copyright 1996, Elsevier Science Ltd. All rights reserved.

No part of this publication may be reproduced in any material

form (including photocopying or storing in any medium by

electronic means and whether or not transiently or incidentally

to some other use of this publication) without the written

permission of the copyright holder except in accordance with

the provisions of the Copyright, Designs and Patents Act 1988

or under the terms of a licence issued by the Copyright Licencing

Agency Ltd, 90 Tottenham Court Road, London, England W1T 4LP.

Applications for the copyright holder's written permission to

reproduce any part of this publication should be addressed to the

publishers.

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

ISBN 0 7506 2529 5

Library of Congress Cataloguing in Publication Data

A catalogue record for this book is available from the Library of Congress

For information on all Butterworth-Heinemann publications

visit our website at www.bh.com

Composition by Genesis Typesetting, Rochester, Kent

Printed arid bound in Great Britain

Contents

Preface to the third edition vii

Acknowledgements ix

1 Introduction 1

2 Definition and regulation 5

3 Ship form calculations 19

4 Flotation and stability 30

5 The environment 81

6 Seakeeping 100

7 Strength 121

8 Resistance 173

9 Propulsion 209

10 Manoeuvring 252

11 Vibration, noise and shock 276

12 Ship design 304

Appendix: Units, notation and sources 347

Index 353

V

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Preface to the third edition

One definition of wisdom is the thoughtful application of learning;

insight; good sense; judgement. It can be said that this book aims to

contribute to the reader's wisdom. It sets out to provide knowledge of

the fundamentals of naval architecture so that the reader can define a

ship form, calculate its draughts and displacement and check its

stability. It seeks to give an understanding of other aspects of the ship

such as the possible modes of structural failure and its manoeuvring

and seakeeping performance. It presents information on the environ￾ment in which the ship has to operate, and describes the signs that

might indicate pending trouble.

As with all branches of engineering, naval architecture is changing

dramatically as a result of modern technology. Computers have made a

big impact on the design, construction and operation of ships. New

materials and changing world economics are bringing new ship types

into commercial use or resulting in changes in more established types.

Greater emphasis on protection of the environment has led to new

regulations on waste disposal and the design of ships to minimize the

harmful results of oil spillages and other accidents. There is now

greater attention to safety of life at sea, not least as a result of the tragic

loss of life in passenger ferries such as the Estonia and the Herald of Free

Enterprise.

Because of the rate of change in the subject, new texts are required

not only by those beginning a career in the profession but also by those

already involved who wish to keep their knowledge up-dated. This book

is intended only as an introduction to naval architecture. It sets out to

educate those who need some knowledge of the subject in their work,

such as sea-going engineers and those who work in design offices and

production organizations associated with the maritime sector. It will

help those who aspire to acquire a qualification in naval architecture up

to about the incorporated engineer level. Most major design calcula￾tions are, today, carried out by computer. However, it is vital that the

underlying principles are understood if computer programs are to be

applied intelligently. It is this understanding which this book sets out to

provide for the technician.

vii

viii PREFACE

Apart from ships, many are involved in the exploitation of offshore

energy resources, harvesting the riches of the sea or in leisure activities.

Leisure is an increasingly important sector in the market, ranging from

small boats to large yachts and ferries and even underwater passenger

craft to show people the marvels of marine life. All marine structures

must obey the same basic laws and remain effective in the harsh marine

environment.

Many of those working in these fields will have had their basic

training in a more general engineering setting. This volume presents

the essential knowledge of naval architecture they need in a form which

they should find easy to assimilate as part of a course of learning. Those

who are already practitioners will find it useful as a reference text.

Acknowledgements

Many of the figures and most of the worked examples in this book are

from Muckle's Naval Architecture which is the work this volume is

intended to replace. A number of figures are taken from the

publications of the Royal Institution of Naval Architects. They are

reproduced by kind permission of the Institution and those concerned

are indicated in the captions. I am very grateful to my son, Simon, for

his assistance in producing the new illustrations.

ix

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1 Introduction

SHIPS

Ships are a vital element in the modern world. They still carry some 95

per cent of trade. In 1994 there were more than 80 000 ships each with

a gross tonnage of 100 or more, representing a gross tonnage of over

450 million in total. Although aircraft have displaced the transatlantic

liners, ships still carry large numbers of people on pleasure cruises and

on the multiplicity of ferries operating in all areas of the globe. Ships,

and other marine structures, are needed to exploit the riches of the

deep.

Although one of the oldest forms of transport, ships, their

equipment and their function, are subject to constant evolution.

Changes are driven by changing patterns of world trade, by social

pressures, by technological improvements in materials, construction

techniques and control systems, and by pressure of economics. As an

example, technology now provides the ability to build much larger,

faster, ships and these are adopted to gain the economic advantages

those features can confer.

NAVAL ARCHITECTURE

Naval architecture is a fascinating and demanding discipline. It is

fascinating because of the variety of floating structures and the many

compromises necessary to achieve the most effective product. It is

demanding because a ship is a very large capital investment and

because of the need to protect the people on board and the marine

environment.

One has only to visit a busy port to appreciate the variety of forms a

ship may take. This variation is due to the different demands placed on

them and the conditions under which they operate. Thus there are

fishing vessels ranging from the small local boat operating by day, to the

ocean going ships with facilities to deep freeze their catches. There are

vessels to harvest the other riches of the deep - for exploitation of

l

2 INTRODUCTION

energy sources, gas and oil, and extraction of minerals. There are oil

tankers, ranging from small coastal vessels to giant supertankers. Other

huge ships carry bulk cargoes such as grain, coal or ore. There are

ferries for carrying passengers between ports which may be only a few

kilometres or a hundred apart. There are the tugs for shepherding

ships in port or for trans-ocean towing. Then there are the dredgers,

lighters and pilot boats without which the port could not function. In

a naval port, there will be warships from huge aircraft carriers through

cruisers and destroyers to frigates, patrol boats, mine countermeasure

vessels and submarines.

Besides the variety of function there is variety in hull form. The vast

majority of ships are single hull and rely upon their displacement to

support their weight. In some applications multiple hulls are preferred

because they provide large deck areas without excessive length. In

other cases higher speeds may be achieved by using dynamic forces to

support part of the weight when under way. Planing craft, surface effect

ships and hydrofoil craft are examples. Air cushion craft enable shallow

water to be negotiated and provide an amphibious capability. Some

craft will be combinations of these specialist forms.

The variety is not limited to appearance and function. Different

materials are used - steel, wood, aluminium and reinforced plastics of

various types. The propulsion system used to drive the craft through the

water may be the wind, but for most large craft is some form of

mechanical propulsion. The driving power may be generated by

diesels, steam turbine, gas turbine, some form of fuel cell or a

combination of these. The power will be transmitted to the propulsion

device through mechanical or hydraulic gearing or by using electric

generators and motors as intermediaries. The propulsor itself will

usually be some form of propeller, perhaps ducted, but may be water or

air jet. There will be many other systems on board - means of

manoeuvring the ship, electric power generation, hydraulic power for

winches and other cargo handling systems.

A ship can be a veritable floating township with several thousand

people on board and remaining at sea for several weeks. It needs

electrics, air conditioning, sewage treatment plant, galleys, bakeries,

shops, restaurants, cinemas, dance halls, concert halls and swimming

pools. All these, and the general layout must be arranged so that the

ship can carry out its intended tasks efficiently and economically. The

naval architect has not only the problems of the building and town

designer but a ship must float, move, be capable of surviving in a very

rough environment and withstand a reasonable level of accident. It is

the naval architect who 'orchestrates' the design, calling upon the

expertise of many other professions in achieving the best compromise

between many, often conflicting, requirements. The profession of naval

INTRODUCTION 3

architecture is a blend of science and art. Science is called upon to

make sure the ship goes at the intended speed, is sufficiently stable and

strong enough to withstand the rigours of the harsh environment in

which it moves, and so on. The art is in getting a judicious blend of the

many factors involved so as to produce a product that is not only

aesthetically pleasing but is able to carry out its function with maximum

effectiveness, efficiency and economy.

Naval architecture is a demanding profession because a ship is a

major capital investment that takes many years to create and is

expected to remain in service for perhaps twenty-five years or more. It

is usually part of a larger transport system and must be properly

integrated with the other elements of the overall system. The

geography of, and facilities at, some ports will restrict the size of ship

that can be accommodated and perhaps require it to carry special

loading and discharging equipment. An example of this is the

container ship. Goods can be placed in containers at the factory where

they are produced. These containers are of certain standard dimen￾sions and are taken by road, or rail, to a port with specialized handling

equipment where they are loaded on board. At the port of destination

they are offloaded on to land transport. The use of containers means

that ships need spend far less time in port loading and unloading and

the cargoes are more secure. Port fees are reduced and the ship is used

more productively.

The designer must create the best possible ship to meet the

operator's needs. In doing this he must know how the ship will be used

and anticipate changes that may occur in those needs and usage over

the years. Thus the design must be flexible. History shows that the most

highly regarded ships have been those able to adapt with time.

Most important is the safety of ship, crew and environment. The

design must be safe for normal operations and not be unduly

vulnerable to mishandling or accident. No ship can be absolutely safe

and a designer must take conscious decisions as to the level of risk

judged acceptable in the full range of scenarios in which the ship can

expect to find itself. There will always be a possibility that the

conditions catered for will be exceeded and the risk of this and the

potential consequences must be assessed and only accepted if they are

judged unavoidable or acceptable. Acceptable, that is, by the owner,

operator and the general public and not least by the designer who has

ultimate responsibility. Even where errors on the part of others have

caused an accident the designer should have considered such a

possibility and taken steps to minimize the consequences. For instance,

in the event of collision the ship must have a good chance of surviving

or, at least, of remaining afloat long enough for passengers to be taken

off safely. This brings with it the need for a whole range of life saving

4 INTRODUCTION

equipment. The heavy loss of life in the sinking of the Estonia in 1994

is a sad example of what can happen when things go wrong.

Cargo ships may carry materials which would damage the environ￾ment if released by accident. The consequences of large oil spillages are

reported all too often. Other chemicals may pose an even greater

threat. The bunker fuel in ships is a hazard and, in the case of ferries,

the lorries on board may carry dangerous loads. Clearly those who

design, construct and operate ships have a great responsibility to the

community at large. If they fail to live up to the standards expected of

them they are likely to be called to account1

.

Over the years the safety of life and cargo has prompted governments

to lay down certain conditions that must be met by ships flying their

flag, or using their ports. Because shipping is world wide there are also

international rules to be obeyed. In the case of the United Kingdom

the government department affected is the Department of Transport

and its Marine Safety Agency. International control is through the

International Maritime Organisation.

It is hoped that these few paragraphs have shown that naval

architecture can be interesting and rewarding. The reader will find the

various topics discussed in more detail in later chapters where the

fundamental aspects of the subject are covered. The references at the

end of each chapter indicate sources of further reading if it is desired

to follow up any specific topic. A more advanced general textbook2

can

be consulted. This has many more references to assist the interested

reader. For comments on references see the Appendix.

References

1. Rawson, K. J. (1989) Ethics and fashion in design. TRINA.

2. Rawson, K. J. and Tupper, E. C. (1994) Basic Ship Theory. Fourth Edition,

Longman.