Decoding History: The Battle of the Atlantic and Ultra PDF
Preview Decoding History: The Battle of the Atlantic and Ultra
Decoding History Also by W. J. R. Gardner ANTI-SUBMARINE WARFARE Decoding History The Battle of the Atlantic and Ultra W. J. R. Gardner Historian Naval Historical Branch Ministry of Defence Foreword by Geoffrey Till Dean of Academic Studies Joint Services Command and Staff College Bracknell © W. J. R. Gardner 1999 Foreword © Geoffrey Till 19 99 Softcover reprint of the hardcover 1st edition 1999 978-0-333-69303-2 All rights reserved. No reproduction, copy or transmission of this publication may be made without written permission. No paragraph of this publication may be reproduced, copied or transmitted save with written permission or in accordance with the provisions of the Copyright, Designs and Patents Act 1988, or under the terms of any licence permitting limited copying issued by the Copyright Licensing Agency, 90 Tottenham Court Road, London W1POLP. Any person who does any unauthorised act in relation to this publication may be liable to criminal prosecution and civil claims for damages. The author has asserted his right to be identified as the author of this work in accordance with the Copyright, Designs and Patents Act 1988. First published 1999 by MACMILLAN PRESS LTD Houndmills, Basingstoke, Hampshire RG21 6XS and London Companies and representatives throughout the world ISBN 978-1-349-40157-4 ISBN 978-0-230-51014-2 (eBook) DOl 10.1057/9780230510142 A catalogue record for this book is available from the British Library. This book is printed on paper suitable for recycling and made from fully managed and sustained forest sources. 10 9 8 7 6 5 4 3 08 07 06 05 04 03 02 01 Contents List of Tables vi List of Figures vii Foreword by Geoffrey Till ix Acknowledgements xii Glossary xiv List of Convoys Mentioned in the Text xvi 1 The World War and the Atlantic Campaign 1 2 Chronology, Time and Measurement 17 3 The Economic Context 34 4 A German Perspective 55 5 Convoy Warfare 69 6 Technology on Both Sides 91 7 Signals Intelligence and the Battle of the Atlantic 120 8 Case-Study I: 1941 146 9 Case-Study II: Mid-1942 to Mid-1943 178 10 Conclusion: Evaluating Plays and Actors 210 Notes 219 References and Bibliography 249 Index 257 List of Tables 1.1 The levels of war 3 2.1 Looking at time 23 2.2 War and time 26 6.1 Surface-ship escort - desired characteristics 110 8.1 U-boat fleet growth, mid-1940 to end 1941 149 8.2 Growth in numbers of submarine 173 9.1 Convoy losses by type 186 9.2 Douglas and Rohwer data - comparison 187 9.3 Submarine deployment - 18 March 1943 190 List of Figures 2.1 Closing the air gaps - distance and time 29 3.1 Simplified shipping model 45 5.1 Theory of convoy I 71 5.2 Theory of convoy II 75 5.3 Submarine attack - the ORCA concept 84 5.4 ASW in 1939 - comparative ranges 87 5.5 ASW in 1943 - comparative ranges 89 7.1 High-frequency propagation 122 7.2 Direction-finding accuracy 127 7.3 Decrypt reading times 143 8.1 Tonnage warfare patterns 151 8.2 Convoy and independent losses 153 8.3 Losses by operation type 156 8.4 Productivity flow 161 9.1 Boat-days and tons sunk 193 9.2 Tons sunk per U-boat day 195 9.3 Merchant-submarine exchange rate 198 9.4 Submarine losses 199 Foreword The Battle of the Atlantic was the great maritime encounter of the Second World War in Europe. In this campaign, or battle, as it is usually if confusingly known, a continental power sought to exploit the vulnerabilities of the maritime coalition that threatened it by attacking its weakest link, namely the shipping that crossed and recrossed the broad Atlantic, carrying military equipment and person- nel and all the requirements of the British war economy. It was one of the few battles that regularly kept Churchill awake at night, for he knew how crucial its outcome was for Britain's capacity to survive, let alone prosecute an offensive war. It was a huge affair, involving hundreds of U-boats, thousands of ships, aircraft and people and it lasted for the better part of six years. Naval personnel on both sides, the merchant sailors of many different countries, airmen, scientists, code-breakers, logisticians, dockers and factory-workers all had their crucial roles to play - and suffered accord- ingly. To use Jock Gardner's own analogy, it was the great maritime drama of the war and it ran and ran. Not surprisingly therefore, when confronted with such a huge and complicated matter, most people seek, and often need, a guide to what really mattered, to what worked, to what made the crucial difference. This applies as much to historians bewildered by the mass of some- times conflicting but always competing data as it does to participants in the battle who want to understand, or at least to confirm (since they usually exhibit strong experience-based views on this already), how their efforts fitted in to the whole. Accordingly, books about the Battle of the Atlantic usually refine the complexity and focus on particular aspects of the case. And the ex- planations came in waves. First was the obvious focus on the dramatic operational and tactical levels of the campaign, sustained by the pro- cessing of official Admiralty and German naval records and a flood of gripping personal reminiscence from both sides. At first this was almost exclusively the domain of the professional military on both sides, but soon important contributions to an evolving debate were made by the chief victims of the battle, the merchant sailors who suffered so much in the Allied cause. Very soon books which sought to compare and contrast the role played by the forces of the various nations involved
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