A World at Arms (77 page)

The Japanese submarine fleet had been developed originally as an auxiliary to her surface fleet in the strictest sense, that is, as a means of aiding the fleet in combat against the navies of her enemies, particularly the United States. Before Yamamoto forced Imperial Naval Headquarters to adopt his Pearl Harbor plan in the fall of 1941, the Japanese intended to use their submarines for harrying the American navy, reducing its size by torpedo attacks as it moved across the Pacific, leaving it smaller and damaged enough to be overwhelmed by the Imperial fleet. When this operational plan was scrapped in favor of Yamamoto’s concept, there was no reorientation of the submarines’ employment doctrine, a reorientation for which there was little time and which was in any case rendered unlikely by the surface fleet orientation of those in the highest command positions of the submarine branch.
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The Japanese submarines continued to be used primarily to assist the surface fleet, especially in the long naval campaign in the Solomon
Islands. They had actually been quite successful against shipping in the Indian Ocean in April, 1942, but this was seen as an aberration in the employment of submarines. The Germans repeatedly tried to explain to their ally that the best hope for the Axis was to paralyze their enemies by attacks on shipping, attacks in which the possible increment provided by Japan could be of great significance. To assist them in their project, the Germans offered to provide some of their own submarines as models and eventually gave them two early in 1943. Of these one made it to Japan.
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But, though some German ideas were copied in Japan, in part because of engineers sent from Germany,
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the Japanese never were able to act on their newly grasped understanding of the importance of the campaign against Allied merchant ships because of developments in the Pacific War which they had not anticipated.

The combination of American attacks, primarily by submarines, on Japanese shipping with General MacArthur’s strategy of by–passing Japanese garrisons in the Southwest Pacific, increasingly forced the Japanese navy into an entirely new pattern of submarine employment. If the Japanese garrisons isolated by American and Australian advances were to remain even minimally effective militarily, they had to be supplied with certain essential items: ammunition, spare parts, and medical supplies. Submarine supply was becoming the only way to deliver these items, and submarine commanders who had once disdained as unheroic a campaign against merchant shipping found themselves engaged in the equally hazardous but even less heroic business of carrying sacks of rice and crates of ammunition to the remnants of Japan’s outer garrisons. Simultaneously, the emphasis in the submarine construction program, far from following in the footsteps of German models, was shifted increasingly toward the building of larger supply submarines which would deliver a larger volume of cargo to the isolated units in the Southwest Pacific.
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The Japanese were certainly very alarmed by the turn in the Battle of the Atlantic in May 1943, learning about it very quickly from the dramatic change in German announcements of the tonnage sunk by the U-Boats.
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The Germans explained the role of airborne radar and escort carriers as the main causes of their set-back and informed the Japanese of their plans for new technologies to revive the effectiveness of the U-Boats, thereby unknowingly tipping off the Allies who were reading the Japanese reports.
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One of the other ways for the Germans to cope with the defeat in the North Atlantic, however, was to shift the submarine campaign into less dangerous areas in which to operate, and in this regard cooperation between Germany and Japan was of special importance.

Since the Japanese did not have submarines to spare for a major campaign against shipping, they provided bases for a small fleet of German submarines sent to Malaya to operate from bases there, primarily at the important port of Penang, against the Allied supply routes across the Indian Ocean. It is no coincidence that the program began in the summer of 1943 with operation “Monsoon,” the dispatch of eleven submarines and one supply submarine to Malaya. Five of the submarines actually arrived and others followed. Using the bases provided by the Japanese, these German submarines did have some successes, and more were sent thereafter; but their number was not large enough to make a major contribution in the tonnage war.
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Their last significant successes in early 1944 were restricted by Allied use of information from broken German enigma codes to destroy their supply ships.
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In May 1945, the remaining four German and two Italian submarines were taken over by the Japanese when the German naval attaché in Tokyo ordered the local German commander, who wanted to go on fighting, to surrender.
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The Allied landing in France in June 1944 led to the capture by the French Maquis and their turning over to the Allies the captain and the May 1943 to June 1944 log Of U-188, one of the submarines which had been based in Penang; and this material provided the Allies at the time as it does historians later–with considerable insight into the situation at that base and in the Indian Ocean.
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The immediately more obvious result of the invasion was the loss by the Germans of submarine bases on the French Atlantic coast, and their inability to use those which they continued to hold but with hopelessly isolated garrisons. This led the Japanese beginning in September 1944, to urge the Germans to send additional submarines to East Asia; they did send some, but not nearly as many as the Japanese would have liked. Even reference to the sinking of the
Tirpitz
and the resulting release of British warships from European to East Asian waters did not convince Dönitz, who preferred to keep most of his submarines based in Norway and Germany.
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In April and May of 1945, as Germany was collapsing, and while Dönitz still hoped for a turn of the tide to be brought about by his new submarine models, the Japanese made a final effort to have the Germans transfer to East Asia large numbers of their submarines. At this time over 350 were in service, and the Japanese appear to have believed that their use in the Pacific War could make a substantial difference there. In spite of repeated and evidently agitated meetings with Dönitz, von Ribbentrop, Keitel and others when he could not get to see Hitler, the head of the Japanese military delegation in Berlin, Vice Admiral Abe Katsuo, was unable to budge the Germans. They explained to their
anxious ally that there was not enough oil to send so many on the long journey; only the two or three already scheduled to go would be sent; but when they had recaptured the oil fields near Vienna they would reconsider!
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The German reaction to their defeat of May 1943 relied on their allies only to a small extent. Other than shifting submarines to less threatened even if less remunerative operational areas, they depended on technical and tactical innovations. For some time the German leadership had considered alternative types of submarines. The most important problems as they saw them were the problems of underwater speed, above surface defense against airplanes, and means for coping with the escorts. In a major conference at Hitler’s headquarters on September 28, 1942, the leaders of the navy, then Raeder, Dönitz and Admiral Fuchs, the man in charge of naval construction, had reviewed the U-Boat war. The discussion included the immense advantages of a new type of U-Boat, called the Walter boat after its inventor, which was propelled under water at 20 knots or faster (almost three times the speed of the current U-Boats and faster than most escorts). It was decided to start building a small version of this new type.
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Dönitz, however, was at this time still confident that his old dependable types could do the job, especially as their numbers were now increasing to the levels he had long demanded.
^d
The defeat in May, on which Dönitz, by now Commander-in-Chief of the navy as well as commander of the U-Boats, had to report to Hitler on June 5, led to new decisions.
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Dönitz placed much of the blame for the defeat on the lack of air support for the U-Boats, possibly a partially correct explanation, but a deficit which at a time when the demands of the Eastern and Mediterranean fronts and home defense against air raids were steadily increasing was not likely to be remedied.
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The successes of the Allies were blamed on the radar carried by their airplanes. This was certainly in part correct. The very productive British series of air attacks on U-Boats passing in and out on their way to or from their operational areas across the Bay of Biscay in June and July 1943 reinforced this impression and diverted attention from the Allied successes in code–breaking and the use of Huff-Duff.
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If this transit had to be made submerged, an intolerable amount of time would be taken up in an unproductive manner. The alternative was to provide the submarines with more anti-aircraft guns
so they could fight it out with the planes; this was done but did not solve the problem. What appeared to be needed were new devices to detect and give warning of Allied radar fixes, new torpedoes to cope with the escorts, and, above all, new types of submarines.

The new radar detection devices were never developed; in this field the Germans remained behind the Allies. New acoustic torpedoes which followed the sound of an attacked ship, altering course when necessary, were already under development and began to be used in the fall of 1943. With these, especially the more effective of the two, the “Zaunkonig”, called “Gnat” by the British, the U-Boats did attain some successes; but the Allies developed counter–measures rather quickly, and the submariners were often misled as to the effectiveness of this device.
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The Germans also introduced radio–guided glider bombs, first used, ironically, against the escaping Italian navy in September 1943, and an airborne guided rocket missile; these were highly effective but available only in limited quantities.
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The main emphasis, as Dönitz explained to the higher commanders of the U-Boat war on June 8, 1943, was on the new types of submarines; the rest of 1943 would be bad, but in 1944, 1945, 1946, and 1947 the situation would become steadily better.
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The Germans decided that it would take too long to develop and bring into service the original Walter boat and instead ordered a modified electro–boat version in two sizes, a small one for the Mediterranean, Black Sea, and Baltic (Type XXIII), and a big one for the oceans (Type XXI). Approved by Hitler on July 12, the new construction program called for 140 of the small and 238 of the big boats. In a desperate race against time, the German construction yards, building the new types in sections for later assembly, struggled to get these ships built, beginning in December 1943, even as the Allied bombers attacked the yards and supplies. It was a race which will be examined again in
Chapter 14
; suffice it to say here that the Allies won. Of Type XXIII, 61 were built, but only five were ready by the end of the war; while of the oceanic Type XXI, 120 were built but only one started on an operational cruise on April 30, 1945.
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Like the whole U-Boat program, the effort to construct hundreds of the new submarines dug deeply into the available supply of high-grade steel, desperately needed for making tanks and other weapons. In this regard, the turn in the war in the Atlantic, by leading the Germans to an enormous investment of material and workers into a naval program that never paid off did have an effect on the land battles in Europe in 1944 and 1945. Literally thousands of tanks were not built by the Germans because of their massive allocation of scarce resources to the program for a new form of submarine warfare.
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In the meantime, the Allies had to cope with the old types of submarines, of which 250 were under construction in July 1943 when the shift to new types began but the old ones were still being completed.
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The Allies knew about the German plans for new types as a result of their ability to read the detailed reports on them which the Japanese naval attaché in Berlin sent back to Tokyo. They had every reason to be concerned but would rely on the Japanese to keep them unintentionally informed both of progress and, in their eyes even more encouraging, the delays imposed primarily by bombing on the German program.
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A major way of striking at the existing type of submarines had been the attacks on them as they crossed the Bay of Biscay. If this was primarily a British operation, the Americans concentrated on exploiting the breaking of German submarine codes to catch the supply submarines when they were on the surface refueling other submarines. Using various techniques to obscure the fact that signal intelligence was the real basis of the strikes, the Americans launched a very successful series of such attacks in the same months of June and July 1943.
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With these and other measures, the Germans were held in check, their new torpedoes and anti-aircraft guns warded off, and the tonnage war won by the Allies. Only the underwater breathing apparatus developed by the Germans, called snorkel, and fitted to many of the older submarine models, gave the Germans some relief and the Allies some additional losses and worries,
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but in the meantime their own construction of merchant ships and escort vessels continued in high gear. The new German offensive of September 1943 to May 1944 was a failure: for sinkings of 411,000 tons in seven months, they lost 119 U-Boats.
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The submarines fought on, disappointed in the obvious inadequacy of their new weapons, but grimly continuing in fatalism and fear.
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It must not be thought, however, that the Allies simply relied on the techniques of anti-submarin warfare that gave them victory in May 1943. Pressed by the desperate shortage of shipping, they too experimented with new devices, some of them on the outlandish side. There had been an early American scheme to construct concrete barges and another to build huge numbers of shallow–draft “sea otters” powered by banks of standard gasoline engines.
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Beginning in December 1942, the British worked on a device long favored by Churchill called the Habakkuk, a flat–surface artificial iceberg, propelled by banks of outboard motors, and designed to serve as floating airfields to close the air gap in the Atlantic, and later to provide air cover for invading Allied expeditionary forces. The inability of the British to provide the necessary resources and the objections of the American navy kept this project from
getting very far beyond the drawing boards where it remained after the escort carriers came to be available.
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Whatever the attraction of the Habakkuk concept, the reality of escort carriers used for escorting convoys, ferrying airplanes and providing air support for actual invasions was too clearly superior.
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