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1-55750-158-0
263 pages

Foreword; Acknowledgements; Glossary; maps; diagrams; tables; Notes; References and Bibliography; Index

   W.J.R. Gardner sets an ambitious goal of considerable magnitude and complexity in his new book: revisiting every aspect of the entire Battle of the Atlantic in order to assess the importance of Ultra in that part of the Second World War. This approach means the author must recapitulate much of what many readers will think they already know. To begin with, he dissects the nomenclature and hierarchy of combat operations and methodically explains how, despite the term "Battle of the Atlantic," this was actually a larger event comprising an accretion of campaigns, battles, and engagements.
   This kind of analysis and definition, unhindered by preconceptions, can prove helpful when vacuuming away layers of accumulated historiographic silt, but it can also be painfully pedantic, as when Gardner opens his second chapter.

   It is very difficult to understand specific parts of the Battle of the Atlantic—whether they are defined by period or subject—without having at least a basic knowledge of the whole series of campaigns that form the struggle. This is probably best done by means of a chronological presentation and the case studies which are given later in the book should, in particular, be viewed in such context among others. Although these can be read as monographs, some of their value is lost without an appreciation of the whole of which they form part. The Battle of the Atlantic underwent several changes of scale, nature and intensity and was never lacking in strategic significance. In this work, which is concerned with assessing the overall impact of one specific field, Ultra, on a larger whole, it is necessary to comprehend this whole before turning to looking at the particular. A chronology is probably one of the most practical ways of achieving this purpose. However, the mere chronological presentation of information is sometimes derided in historical writing, but as well as being significant in itself it is an essential foundation for much subsequent analytical work. This latter point is expanded on in two ways in the latter part of this chapter. Firstly, it is suggested that time is woven so deeply into perception of events and their meaning that its proper significance has a tendency to be ignored, or at least underestimated: here it is intended to redress this imbalance. Secondly, this raises the even less regarded area of measurement, despite its undoubted significance. In order to conduct analyses which have any significance, they must be founded on two sound pillars—data and method. The last part of this chapter will concern itself with some characteristics of the problem of measurement of data. Perhaps, this is an appropriate point at which to reassure readers that this examination will be conducted almost entirely in words and without recourse to complex mathematics.

   As if this isn't thorough enough—and a bit condescending—Gardner includes a helpful endnote.

1. 'Chronology n. (pl. ies) 1 science of determining dates. 2 a arrangement of events etc. in order of occurrence. b table or document displaying this. (Greek khronos time, *-logy).' Definition in the Pocket Oxford Dictionary 1994.

   This tedious and overbearing style not only vacuums away the silt, it also sucks all the pleasure off Gardner's heavily annotated pages, but those readers who persevere and have a deep interest in the material will eventually discover Decoding History is not without its rewards, difficult though they might be to find.
   As he continues with his lecture, Gardner discusses the eight phases of the Battle of the Atlantic and then defines "frames," "windows," and "connections" as three ways of looking at time and admonishes the reader "Despite this threefold split, time remains indivisible; however, it is strongly suggested that it should be looked at in more than one way. Certainly, if this under-regarded and implicit dimension is not taken proper account of, then it is likely to lead to flawed conclusions at best."
   Having explained the nature of time as it applies to the Battle of the Atlantic, the author delves into the distinction between precision and accuracy in measurement and offers an example.

   ...A fairly normal practice of the period would be to render these thus:

      50° 06' North 42° 23' West

   This in words would be:

      50 degrees 6 minutes North, 42 degrees 23 minutes West

   At such latitudes, and indeed any likely to be used during the Battle of the Atlantic, this precise form of expression would imply an order of accuracy of better than one nautical mile. Under certain circumstances, such as being in sight of land, or recently having obtained a good stellar fix, this might be possible but for the rest of the time—which was by far the longest period—it was not. Nevertheless, the precise form conceals the inaccurate reality and this is a difficulty which stands in the way of the complete and reliable reconstruction of operations with confidence.

   Gardner next touches upon some of the economic considerations influencing the Battle of the Atlantic. This overview includes his thoughts on how availability of shipping went far beyond "existing stock plus new construction minus losses" to include a rather nebulous "efficiency" factor and other complex considerations. He also makes the point that these kinds of factors and coefficients would be difficult enough to calculate in today's world of instant communications and information technology; during the war they were almost impossible for the Allies to know and far beyond the ken of Admiral Doenitz and his staff despite their efforts to fashion strategy based on their incomplete grasp of the Allied shipping situation. This was especially true of Doenitz's decision in mid-1943 to maintain the costly, unproductive U-boat campaign in the belief that it would tie down greater Allied resources in relation to expenditure of German resources.
   When analyzing the German perspective on the campaign, Gardner has much to say about how Doenitz stamped his philosophy and personality on his organization. Somewhat incongruously, he quotes a paragraph from The Economist magazine about Microsoft to draw a parallel between Doenitz and Bill Gates. Gardner also evaluates the relatively puny size of BdU (the U-boat headquarters) and concludes that the organizational structure and lack of broader support staff worked against the Germans in the long run as they had little time themselves, and no one else available, "to take longer term analytical views."

   The greatest (and very much linked) failures were a growing inability to recognise the situation in which they were and a failure to analyse their problems sufficiently well to allow effective remedial action. Thus the growing lack of understanding of enemy performance went hand in hand with declining results from the U-Bootwaffe, and tactical failure at sea was echoed in the inability at the strategic level to deploy the newest technology submarines from which so much was expected. In the end, Doenitz and his submarines were outbuilt and outfought, but they were outthought, too. Over the first, they had ultimately virtually no control, at least after the USA was engaged; the second was perhaps more evenly balanced until the last two years of the war, but the last was largely attributable to deep-seated and inherent flaws in them and in their system.

   In his chapter on the convoy system, the author explicates the theory and practice of convoying. He points out the first and simplest form of protection offered by grouping vessels into organized convoys: due to the overlapping circles of visibility of ships in formation, it proved much more difficult for them to be visually located at sea by U-boats. Gardner also glances at the numerical requirements of escorts for small convoys versus large convoys and the relationship between the cycles of fewer large convoys as opposed to more smaller convoys. He also discusses weather, navigation, the speed of merchant vessels and the results of including and excluding ships of certain speeds, and so on.

   ...[I]t is clear that the convoy system generally was a success. It maximised the delivery of necessary cargoes and minimised losses. It is difficult to make this point statistically, not because there is a lack of data, but rather because there is a very great deal of it and it is very complicated. Overall figures suggest that it was at least twice as dangerous for a ship to sail independently as in convoy. There were certainly large-scale disasters to convoys, such as SC42, TM1, HX229/SC122 and (outside the Battle of the Atlantic arena) PQ17 but these must be considered as very rare against a total figure of over 25,000 convoys run.

   The remainder of this chapter then slices into very thin pieces the distinct phases of a wolfpack's sighting of and attack against a convoy, placing each cross-section under a microscope and studying German procedures in comparison to Allied responses. Gardner measures the effectiveness against German tactics of Allied sensor systems and weapons and shows how the improvements in technical efficiency during the war lessened German effectiveness in each of the "ORCA" (Outer, Reconnaissance, Closure, Attack) phases of U-boat attacks.
   In his next chapter Gardner outlines the sensors, weapons, and support systems available to the U-boats and their adversaries. He discusses specifications and tactical use of torpedoes (including FAT, LUT, and homing), mines, deck guns, Sonne (German navigational beacons), kites, Aphrodite and Thetis decoys, Alberich (rubber coating on submarine hulls), Kurier radio transmissions, Leigh lights, sonar/asdic, MAD, sonobuoys, various radar types and radar-detection sets, HF/DF, anti-submarine rockets, ramming, depth charges, retro-bombs on MAD-fitted aircraft, K-guns, Y-guns, Hedgehog, Mousetrap, Squid, and Foxer. He also investigates "soft" technologies such as Combat Information Centers and Operational Research.

   ...A good and relatively early example of [Operational Research] was the study of depth-settings of air-dropped depth-charges. It was evident that very few such attacks resulted in significant damage, far less sinkings of submarines. Despite the relatively low lethal radius of depth-charges, performance should have been better. Analysis of attacks adduced the fact that most occurred either with the submarine on the surface or having submerged only a few seconds before the attack. However, then current doctrine dictated a depth-setting of some 100 feet as a notional average submarine operating depth. That it may have been, but it did not apply in the circumstances of an airborne attack. Thus the OR staffs agitated for much shallower depth settings. These were in turn reduced to 50, then 25, feet and lethality improved correspondingly. OR staffs also did good work on the improvement of aim-points and the recommendation for more powerful explosive fillings.

   In the final chapter before his case studies, Gardner examines the basics of signals intelligence, beginning as usual with definitions and setting all the aspects of the subject into their appointed places. "But perhaps the most important thing to remember is that Ultra by whatever name it was known was only a part of Comint, in itself a subset of Sigint and even that was a component of a whole range of intelligence available to the Allies." The author then offers a brief course in the fundamentals of radio waves, the communications technologies that existed during the war, and the techniques used by the military to take advantage of these technologies. Against this background Gardner adds some details about HF/DF, breaking low-grade German maritime ciphers, Radio Finger Printing, TINA (identifying the Morse "fist" of specific operators), and traffic analysis. Gardner then delves into the nitty-gritty of codes and codebreaking in general and Ultra in particular, with the usual explanation of Enigma machines and the successes at Bletchly Park in providing real-time decrypts. He further explains the ups and downs of these successes as German refinements cancelled British achievements. Of course, the Germans were also reading British signals, a fact of which the Allies ironically became aware due to their own codebreaking. On the other hand, the Germans remained blithely unaware that their Enigma system had been compromised, this despite a number occasions on which the Allies nearly revealed their hand. The Germans realized something was amiss, but could not bring themselves to believe their codes had been penetrated.
   After 145 pages of introducing his topic, defining terms, and setting parameters, Gardner produces a pair of case studies intended to explore his main subject matter, the extent to which Ultra affected the Battle of the Atlantic.
   The first case study analyzes the U-boat campaign in the Atlantic in 1941. Gardner calculates average numbers of boats at sea, tonnages sunk each month, monthly U-boat productivity, losses of independently-routed shipping versus ships in convoy, losses inflicted by solo attacks, by ad hoc groups, and by formal "wolfpack" operations. These numbers he measures against dozens of factors in an effort to determine the primary cause or causes of declining U-boat results in the second half of the year. Despite the detailed quantification and evaluation, no easy explanation emerges. Gardner does punch holes in the theory espoused by some writers that Ultra alone had such an impact that the Allies managed to save two million tons of shipping in the last six months of 1941 which would otherwise have been sunk.

   What should be clear from this is that it is very difficult indeed to attribute a single cause to what happened. It is suggested that it is far more difficult still to adopt a single reason for what did not happen. Thus the claim that 1.5-2 million tons was saved by Ultra in the second half of 1941 cannot survive proper scrutiny.
   But neither does this mean that Ultra had no utility at all. It did enable—when available in a timely fashion—more reliable evasive routeing of convoys. But this sometimes occurred even before Ultra, although less successfully and, in any case, it was perfectly possible for the Germans to fail to find convoys, even when no Ultra was helping the Allies and they had the advantage of their own intelligence and even sighting by aircraft to assist them. Ultra was a major factor in the events of 1941 but it was not the only one and it is now all but certain that it was not responsible for saving shipping in the order of 2 million tons.

   In his second case study, Gardner looks at the period from mid-1942 to mid-1943. This begins with another fairly heavy dose of quantifying factors such as the relationship between numbers of convoys intercepted and convoys attacked, boat-days and tonnages sunk, the merchantman/U-boat exchange rate, and so on. From these figures the author attempts to derive underlying events, trends, causes, and effects. With this in hand, he proceeds to analyze the importance of each measure and counter-measure, studying in particular Doenitz's decisions to turn from operations in the North Atlantic to attacks on UGS and GUS convoys in the central Atlantic and to make renewed efforts against distant theaters such as the Caribbean, West Africa, and the Indian Ocean. As usual, the relationship among all the important factors is an analytical maze, but Gardner extracts some clear evidence about the importance of Ultra.

   Looking at the hinge in the Battle of the Atlantic which is represented by late May 1943, the influence of Ultra can be clearly discerned on both sides of that division. Before then, it provided a great deal of background data and, in retrospect, often made it possible to forecast medium-term movements of German submarine groups. It was important in this context of hard convoy battles but it could hardly be claimed as decisive, even by its most ardent proponents. This is not a pejorative statement, merely a reflection of the realities of a series of situations, the causations of any one of which are hard to unravel. To take this further, analysis of the whole period is not easier but what can be done suggests that Ultra's importance changed from time to time within this period and tended to be greater at the higher levels of warfare. From June 1943 onwards, perhaps Ultra gained more importance at the operational and tactical levels but this reflected not only the technical success of codebreaking and growing expertise in exploitation, now taking place in more than one centre, but also the differing nature of the operations to which the intelligence product could be applied.

   In his conclusions, Gardner ranks the influence of Ultra in the Battle of the Atlantic as "more important" rather than "less important" in the hierarchy of factors, but he is careful not to claim too much: "...many of the claims made for the significance of Ultra over the last quarter of a century are overdrawn at best and specious at worst." In response to the view that Ultra was itself the deciding factor, he ends the book thusly:

   ...What is clear is that the previous representation of Ultra as a demon king—either diabolus or deus ex machina—is a gross misinterpretation which, after 25 years, deserves to be put thoroughly and finally to rest.

   In the course of his book, Gardner introduces much, defines much, promises much. When it comes to delivering the goods, not quite as much arrives. Throughout, the author hints at broader issues, more evidence, and deeper meanings but withholds them behind assertions that the material is too complex or too lengthy for this volume. Thus, the payoff never quite lives up to the buildup; in comparison to the long introductory chapters, the case studies are brief and not wholly illuminating.
   This is not an uninformative book by any means, and Gardner obviously knows a great deal about his subject. Still, the nuggets of gold tend to be so difficult to mine from the author's dense, formidable prose that Decoding History is best recommended to an audience of specialists with a serious, scholarly interest in the topic.
   Available from online booksellers, local bookshops, or directly from Naval Institute Press.
   Thanks to NIP for providing this review copy.

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Reviewed 20 February 2000
Copyright © 2000 by Bill Stone
May not be reproduced in any form without written permission of Stone & Stone