Stealth warship technology

REEDS MARINE ENGINEERING AND TECHNOLOGY

STEALTH WARSHIP

TECHNOLOGY

14

Published by Adlard Coles Nautical

an imprint of Bloomsbury Publishing Plc

50 Bedford Square, London WC1B 3DP

www.adlardcoles.com

Copyright © Christopher Lavers 2012

First published by Adlard Coles Nautical in 2012

ISBN 978-1-4081-7525-5

ePDF 978-1-4081-7553-8

ePub 978-1-4081-7552-1

All rights reserved. No part of this publication may be reproduced in any form or by any means –

graphic, electronic or mechanical, including photocopying, recording, taping or information storage and

retrieval systems – without the prior permission in writing of the publishers.

The right of the author to be identifi ed as the author of this work has been asserted by her in accordance with

the Copyright, Designs and Patents Act, 1988.

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

This book is produced using paper that is made from wood grown in managed, sustainable forests.

It is natural, renewable and recyclable. The logging and manufacturing processes conform to the

environmental regulations of the country of origin.

Typeset in 10.5 pt Baskerville by MPS Ltd

Printed and bound in the UK by MPG Ltd

Note: while all reasonable care has been taken in the publication of this book, the publisher takes no

responsibility for the use of the methods or products described in the book.

The LORD lives!

Praise be to my Rock!

Exalted be God, the Rock, my Saviour!

2 Samuel 22:47 (New International Version – UK)

This page intentionally left blank

CONTENTS

ACKNOWLEDGEMENTS IX

INTRODUCTION X

1 RADAR 1

Early Radar Stealth 6

SR-71 8

Measuring Stealth 11

Maximum Detection Range (MDR) and Radar Cross Section 13

Stealth Approaches 19

2 VISIBILITY 30

Dazzle Camoufl age and the First World War 30

Origins of Camoufl age 36

3 INVISIBLE FUTURES 52

Radar Metamaterials 54

Optical Metamaterials 59

4 INFRARED 66

Infra-red Heat Reduction 66

IRCS Contributors 71

The Laws of Infra-red Emission 78

5 MAGNETIC SIGNATURE 82

Magnetic Stealth 82

Degaussing Ships’ Hulls 86

6 THE ACOUSTIC THREAT AND OTHER SIGNATURES 95

Acoustic Noise 95

Various Environmental Factors 97

Active Sonar 98

Passive Sonar 99

Sonar Comparison 100

Cavitation 102

Future Acoustic Technology 103

Bioluminescence 104

Wake Eff ects 105

Extremely Low-Frequency (ELF) Signature 108

Likely Future Cross Sections 108

Biologically Inspired Design 109

Emissions Control Policy 111

viii • Contents

7 MODERN STEALTH SHIPS 114

Sweden 114

United Kingdom 119

Italian and French Destroyer Variants 128

United States of America 130

India 132

Russia 133

France 134

Saudi Arabia 136

Singapore 136

Germany 137

China 138

8 FUTURE NAVAL STEALTH PLATFORMS 141

Queen Elizabeth-Class Aircraft Carrier 142

A Brief History of the Build So Far 144

Radar and Weapons Systems 146

Embarked Fleet Air Arm? 146

Carrier Construction 147

HMS Queen Elizabeth (R08) 148

UK FSC or Type 26 Frigate 149

Weapons and Systems 151

Modular and Flexible 151

United States of America 152

SUMMARY 158

APPENDIX: KEY SHIP FACTS 160

GLOSSARY 167

ANSWERS TO NUMERICAL QUESTIONS 169

IMAGE SOURCES 170

INDEX 171

I would like to thank the following: Mr John Mc Crae for permission to use Type 45

Destroyer HMS Daring images at various construction stages; Mr Andrew Valente,

Combat Index Webmaster, LLC, Naples, Florida, USA for archive imagery access; and

Mr Kjell Göthe, of Kockums Sweden, for Visby stealth corvette pictures and extensive

material about the class. I would also like to thank the meticulous manuscript checking

and copy editing provided by the editorial services team at MPS Limited, Chennai.

I appreciate the BBC Radio 4 ‘Material World’ team for letting me loose to talk live about

stealth concepts before disappearing ‘on air’ (24th April 2008), which fi rst set me on the

path to this book, and the Institute of Physics and the Institute of Materials which both

published early crafting of ‘stealth’ ideas in 2008 and 2009.

I would like to thank my family motivators and in turn encourage them: Helena for

her work with the disadvantaged of Mexico City, Sam for achieving Ten Tors Gold

and teaching in Tanzania, Sara-Kate for her warmth, and care in Guides, Matt for his

application of talents and introducing me to football and Ben for his love of learning

and stories. I thank them for the few hours of reality each day! Your values and passions

add meaning to my life. I thank my parents for motivating me in the past, believing

I could learn to read even when my teachers said I wouldn’t! Finally, I especially thank

Anne, my wife, for her patience and encouragement; you are the true love of my life.

To all and one I thank you.

ACKNOWLEDGEMENTS

The missile navigating by inertial guidance approached with swift self-assurance

the end of its 200 nautical mile pre-programmed journey, and after rapid target

confi rmation with its passive thermal imager reaches its objective to devastating

eff ect. The target, oblivious of its peril, until the fi nal moment of impact, could do

nothing to counter this fatal blow.

Christopher Lavers

The scenario outlined above is not fi ction; it is the real high-technology cutting edge

of naval warfare today. For this reason, surface warships incorporated with stealth

technologies take an increasingly vital role to ensure platform survival. Stealth’s

principal aim is to make naval ships ‘invisible’ to an array of increasingly smart detection

systems such as sonar and radar, combining ways that lower a platform’s emissions and

those which eliminate refl ected radiation, thus reducing detection range and threat

vulnerability. This book seeks to communicate the latest interesting developments

in stealth technology to a wider audience and to explore the paradigm shift ‘stealth’

represents in terms of warship design. It will focus on the transformational change in

naval architecture, which is simplistically represented in the shape of modern warships,

and dwells less on just providing lots of information or technical detail. Stealth Warship

Technology will also discuss in a little detail something of the history of this subject.

In this book, I will provide an opportunity to develop a better understanding of the

specialist practical issues and skills required in this naval sector. Some opportunity for

basic numerical analysis and problem-solving are included at the end of each chapter

for the more mathematical reader. However, the book is designed for those with

a limited mathematical background in mind; it is my objective to communicate the

fundamental principles of the subject to the many and not to provide tricky maths

problems to solve for the few.

I will discuss several ongoing themes or issues throughout the book: surveillance,

signature and cross section reduction as well as certain aspects of electronic warfare

(EW). Surveillance entails an examination of both radar and infra-red non-imaging

target detection systems as well as the latest visual and thermal imaging systems. The

developments in high-resolution radar imaging cannot be underestimated in their

signifi cance at the beginning of the twenty-fi rst century to future platform survivability.

INTRODUCTION

Introduction • xi

Signature and cross section reduction consideration will investigate the various applied

techniques that have been utilised to date and those which are likely to be employed

to make ship targets less visible to current (and future) generations of surveillance

systems. The topic of EW elicits a double-edged response from the informed reader.

EW involves the role of largely passive electronic support measures (ESM), the ‘listening’

devices which need to be coordinated with further electronic countermeasures (ECM)

(various active and passive techniques available), and is both our best friend and, being

also used by an equally surveillant enemy, perhaps our greatest foe.

The aim of this book is to ‘uncover’ the unto now ‘secret’ area of stealth warship design

and the broader aspects of stealth technology using available public material and to

stress the importance of materials used in the warship’s construction with information

that already exists in the public domain, and how this infl uences all of a modern naval

platform’s design parameters. Paradoxically, all the basic stealth concepts are easily

accessible on the Internet, with a variety of stealth-related companies discussing their

products in some detail. To a physicist or engineer who knows what they are looking

for, even YouTube videos can now provide signifi cant intelligence on both systems

and their capabilities and mode of operation, saying nothing of the ability of modern

mobile phones to provide a wealth of additional information and infl uence, as seen

in the Arab Spring of 2011. A working title for this book was initially ‘Electromagnetic

threats to warships’, but this not only fails to grasp the full extent of warship threats

which encompass the traditional role of radar and visual detection, as well as night￾vision devices and thermal imaging capability, but also does not address the acoustic

underwater signature of the ship platform and other less well-known detection methods

such as magnetic signature, bioluminescence, and wake and so on. It must be stressed

from the outset that there has been a signifi cant paradigm shift in warship design in

the past two decades, which has been rather to move away from the view that it is

simply nice to incorporate stealth into warship design as something of an aff ordable

extra if possible. Instead stealth is now seen to be the critical component around which

the warship is designed, and is certainly the case for the DD(X) Zumwalt-class surface

combatant. However, it is the very cost of stealth that has made the Zumwalt a victim

of its own stealth success, and mitigated against the future of the programme, in favour

of a more traditionally tried and tested warships. The shift in emphasis towards stealth

in current platforms is evidenced through the radical transformation of platform design

between the RN Type 23 frigate and the latest stealth Type 45 Destroyer HMS Daring

as well as the La Fayette-class frigate and Swedish Visby stealth class corvette built

by Kockums.

An able reader or student should be able to describe, discuss and analyse the ways in

which modern and often highly complex sensors and communications systems can

xii • Introduction

have their performance degraded by hostile activities. We will consider the various

design techniques which might be incorporated to negate the eff ects of these activities

and to reduce likewise the overall probability of a ship’s detection.

Clearly stealth is only a part of the story, as a stealth warship cannot provide the same

sense of intimidating power projection off the coast of a potential enemy if they do not

know that you are there, and neither can stealth ensure platform safety and integrity

once the fi rst salvo is fi red. Obviously there is still a signifi cant role to be maintained

in terms of self-protection of a platform, and the increased cost that stealth brings to

the value of the ship asset is only likely to increase the required investment in ship’s

defences, be they long- and short-range missile defence systems, a close-in weapon

system (CIWS) or gun as well as various soft-kill methods at the ship’s disposal. Stealth

can actually provide a range advantage over a variety of sensor systems, and the

reduced signature provides a suffi ciently ‘fuzzy picture’ that an enemy may at best

detect you but will be quite unable to classify the threat correctly.

According to Merriam-Webster’s Online Dictionary, ‘stealth’ (pronounced: stelth) is

derived from the thirteenth-century ‘Middle English stelthe; akin to Old English stelan

to steal’, with several related meanings.

1 a archaic: theft b obsolete: something stolen

2 the act or action of proceeding furtively, secretly, or imperceptibly ‘the state

moves by stealth to gather information – Nat Hentoff ’

3 the state of being furtive or unobtrusive [and in the context we will be

considering]

4 an aircraft-design characteristic consisting of oblique angular construction

and avoidance of vertical surfaces that is intended to produce a very weak

radar return

Stealth technology is also known as low observable technology (LOT) and is a sub￾discipline of ECM, which covers a range of techniques used not just with aircraft, but

includes ships and missiles, in order to make them less visible (ideally invisible) to radar,

infra-red and other detection methods.

There are also issues presented by the class of threat that the stealth warship has

been constructed to deal with, as the most likely asymmetric threats that will present

themselves to warships in the near future are the small (and ironically stealthy) fast

boats manned by pirates, insurgents or terrorists, like those who caused damage to

the USS Cole, an Arleigh Burke-class destroyer. The USS Cole was the target of a terrorist

Introduction • xiii

attack in the port of Aden in October 2000, during a scheduled re-fuelling. The attack

killed 17 crew members and injured 39 others, demonstrating that even a heavily

armed high-tech platform is still vulnerable to relatively simple threats (Figure I1).

As the ancient Chinese general Sun Tzu wrote in his The Art of War, dating back to

450 BC and the world’s oldest treatise on military strategy, ‘All warfare is based on

deception’, and certainly warships stealth and signature reduction techniques play an

increasing component in that deception today. Stealth can generally be regarded as any

technique used to reduce refl ected sources of radiation, mostly with passive measures,

whilst signature reduction involves methods designed specifi cally to reduce a ship’s

own emissions – methods which are largely active. In reality, though, the terms ‘stealth’

and ‘signature reduction’ are used fairly interchangeably. The oldest and most successful

recorded reference to deception before the modern era is that illustrated in the book

of Judges (6–7) concerning Gideon who with 300 men, trumpets, torches hidden in jars

and precision timing at the change of the enemy guard routed a much larger force.

15When Gideon heard the dream and its interpretation, he worshiped God. He

returned to the camp of Israel and called out, ‘Get up! The LORD has given the

Midianite camp into your hands.’ 16Dividing the 300 men into 3 companies,

Ÿ Figure I1 The USS Cole (DDG 67) is towed away from the port city of Aden, Yemen, into open

sea by the Military Sealift Command ocean-going tug USNS Catawba (T-ATF 168) on 29 October

2000

xiv • Introduction

he placed trumpets and empty jars in the hands of all of them, with torches

inside … 19Gideon and the 100 men with him reached the edge of the camp

at the beginning of the middle watch, just after they had changed the guard.

They blew their trumpets and broke the jars that were in their hands. 20The

3 companies blew the trumpets and smashed the jars. Grasping the torches

in their left hands and holding in their right hands the trumpets they were

to blow, they shouted, ‘A sword for the LORD and for Gideon!’ 21While each

man held his position around the camp, all the Midianites ran, crying out as

they fl ed.

You could even regard this as the fi rst example of coordinated, network-centric

warfare! Certainly the desire for ‘invisibility’ until the fi nal moment of attack has been

a key infl uence in how warfare has been conducted since ancient times. The military

quest for invisibility appears in Greek mythology: Perseus’ helmet and Gyge’s ring both

rendered their wearers invisible, useful when fi ghting monsters, and also formed the

basis for the ‘One Ring’ in Tolkien’s famous trilogy The Lord of the Rings. However, such

abilities no longer belong entirely in the realm of fantasy or science fi ction such as

Star Trek, as these days the world’s armed forces can draw on sophisticated stealth

techniques to hide themselves from their enemies. Stealth technology seeks to render

military ships, vehicles, men and aircraft ‘invisible’ to modern detection systems, such

as radar and magnetic sensors, by reducing the levels of refl ected radiation whilst at

the same time lowering the craft’s own emissions (Figure I2). I will examine the various

applied techniques that have been, and are likely to be, employed to make a platform

less prone to detection. Certainly if these techniques are applied successfully, eff ective

targeting, although perhaps not impossible, will be highly unlikely, whilst at the same

time countermeasure systems will attempt to deny the enemy the tactical use of the

electromagnetic spectrum (and acoustic spectrum) whilst retaining one’s own use of

military spectral capabilities.

When it comes to an aircraft carrier or large battleship, this is no mean feat. Stealth

works hand in hand with precision, and it is no accident that stealth aircraft today

use precision-guided munitions to great effect. Stealth also works in partnership

with modern decoy systems, as the harder it is to ‘see’ the real target, the more likely

that a decoy system will be selected as the chosen target because of the larger more

attractive signal it may provide. We will start our discussion of stealth with radar, a

sensor many readers will be familiar with, followed by the visible spectrum, infra￾red spectrum, various other spectra and finally an examination of modern stealth

ships themselves.

For me, the real issues of stealth are not driven by academic interest alone but in terms

of considering the safety provided to a vulnerable crew at sea and the preservation and

Introduction • xv

security of our personal and national freedoms won at great corporate and individual

cost. If I may paraphrase Sir Winston Churchill, I anticipate that for the crews of these

ships in future confl icts, with the vast amount of dedicated research that has gone into

UK stealth warship design, never before will so much be owed by so few to so many

for their survival and perhaps the continued security of our nation and its traditions

as well.

It is as true today as in yesteryear that ‘[i]t is on the Navy under the good providence

of God that our health, prosperity and peace depend’ (Britannia Royal Naval College

motto, above the main college doors).

Ÿ Figure I2 Various signatures and cross sections © CR Lavers

This page intentionally left blank