Engineers of Victory: The Problem Solvers Who Turned the Tide in the Second World War (10 page)

Thus, almost any of the thirty-three U-boats that surfaced was swiftly attacked by Liberator and Hudson bombers, which dispatched three submarines to the bottom, including the U 954—among its crew members was Doenitz’s own son, Peter. HMS
Duncan
helped to destroy a fourth attacker, and
Sennen
and HMS
Jed
the fifth. Amazingly, not a single merchantman was sunk; their crews could hear distant noises and observe great explosions on the horizon, but that was the closest the U-boats got. Despite this terrible blow, Doenitz urged his wolf packs to regroup in time for the next big convoy from Halifax, HX 239, but his instructions included the following amazing sentence, swiftly translated at Bletchley Park, which had now regained its capacity to break the Shark codes: “If there is anyone who thinks that combating convoys is no longer possible, he is a weakling and no true U-boat captain.”
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It was around this time that Horton at Western Approaches Command and senior staff at the Admiralty itself began to wonder if the German U-boat crews were starting to lose their nerve and resolution. Perhaps so (it will be discussed shortly), but one is bound to ask what even a determined submarine captain could do by this stage of the fight. For, in addition to the more distant Coastal Command aerial patrols, Convoy HX 239 was accompanied all the way by two of the
new escort carriers, USS
Bogue
and HMS
Archer,
which sank two out of the three U-boats that perished. The convoy arrived in the United Kingdom on May 25, the same date as the slow convoy SC 130, which had enjoyed aerial protection both day and night. The very long-range aircraft had made twenty-eight sightings of U-boats, attacked ten of them, and sunk two. The merchantmen were unscathed. It was an extraordinary reversal of fortunes since HX 229 and SC 122.

At the end of May 1943, Doenitz, ever the sober realist, assessed the results over the past month—a catastrophic total of forty-one U-boats had been lost during those four weeks—and concluded that the North Atlantic had become too hostile an environment for his submariners. The boats would therefore be relocated to the U.S.-Gibraltar routes and farther afield, off the Brazilian and West African coasts or in the Caribbean. As they slipped in and out of their French bases, they would tightly hug the coast of northern Spain and thus avoid the western approaches. The grand admiral was certainly not beaten, but he needed time to think, and time to get newer U-boats, with better equipment, into the hands of his captains. While he did not know quite how it had been done, he could see that Allied forces had made immense leaps forward both in the art of detection and in their capacity for destruction.

Another twelve months would pass, almost exactly, before many of the same Allied aircraft squadrons and escort vessels would be patrolling off the beaches of Normandy, so there was still a way to go. But this is as good a place as any to begin a more detailed analysis of the steady Allied ascendancy in the Atlantic. The first and probably the greatest factor has to be aircraft. The Second World War was the first in the entire history of human conflict in which sea power was decisively affected by airpower. Without the latter, one could not reign supreme in the former.

The best testimony to this fact comes from Doenitz. While he was personally a devoted, unpleasant Nazi, the daily War Book notes from his office were remarkably candid and soberly analytical, whichever way the Battle of the Atlantic was going. His confidential reports to Hitler
about the increasing difficulties the German submarines faced were blunt and honest. Thus, despite his desperate message to his U-boat commanders (mentioned above), he was already writing a dispassionate assessment of the reversal of fortunes, just as convoys HX 239 and SC 130 were entering home waters. In his entry of May 24, 1943, he noted that “the enemy Air Force therefore played a decisive part.… This can be attributed to the increased use of land-based aircraft and aircraft carriers combined with the advantage of radar location.”
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And, years after the war, Doenitz wrote in his memoirs that the chief problem had been that “Germany was waging war at sea without an air arm.”
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That was like boxing with only one fist.

The growth of Allied airpower over the Atlantic took two forms. The first was the advent of VLR aircraft operating from shore-based stations, chiefly the extraordinarily robust American-built B-24 Liberator bombers, but also B-17 Flying Fortresses and the elegant Catalina flying boats, and the tough British-built Wellingtons and Sunderlands. But it was the long-range Liberators that first made the difference. The second was the appearance of purpose-built escort carriers, modest in speed and striking power compared with the
Essex
- and
Illustrious
-class fleet carriers (see
chapter 5
) but extremely suitable for accompanying an Atlantic convoy: their aircraft could patrol the seas for miles around and, like the VLR bombers, carried a whole armory of weapons specially designed to destroy U-boats. Rearmed and refueled on the carriers overnight, they would be ready at the crack of dawn to fly off and suppress, possibly sink, the enemy submarines. As their name implies, these carriers escorted the convoys from Halifax to Liverpool.

The whole phenomenon of “airpower at sea” became so ubiquitous during the Second World War that it can easily be taken for granted, but it is one of the most important and novel aspects of the entire conflict. Doenitz must have known it from the beginning, and it is hard not to feel some sympathy for the hand he had been dealt when he became commander in chief of the German navy at the beginning of 1943: he possessed a few vastly expensive, top-heavy surface warships (but no aircraft carriers), all badly constrained by geography, and a U-boat force (lacking much assistance from the Luftwaffe until too late) that had not only to contest the enemy’s warships but also to handle aircraft that came in fast and deadly.

It is impossible to overstress what this meant for the North Atlantic struggle. Doenitz’s submarine crews found themselves confronted by a whole variety of Allied countermeasures as the spring of 1943 gave way to the summer and autumn; the enemy possessed vastly improved systems of detection and destruction against which even the most modern of the U-boats had less and less chance of success. Above it all, though, there was the factor of continuous air cover for the convoys, and the increasing chance of a U-boat being attacked even as it was in transit, on the surface, perhaps hundreds of miles from a convoy. Aircraft always had the advantage of speed and suddenness over vessels on the surface of the sea. Now they had supplemented this with the newer weapons’ accuracy and lethality. Above all, they now had added range. By mid-1943 a VLR Liberator could be assisting a mid-Atlantic convoy 1,200 miles from its home air base, a phenomenal improvement. Even much earlier, in late May 1941, the German battleship
Bismarck
was spotted heading for Brest by a Coastal Command Catalina based in Iceland, a thousand miles to the north. The
Bismarck
’s crippling by torpedo aircraft and sinking four days later confirmed Doenitz’s prejudices against heavy surface ships, but the larger lesson of 1941 was this: without airpower, control of the seas was precarious, indeed impossible, even for submarines.
^e

No senior commander appears to have realized this before the Second World War began. Both the British and German navies were shortchanged by the existence of independent air services that had designed themselves for essentially land-bound purposes: the Luftwaffe in its focus upon tactical air support for the army, medium-range bombing, and (increasingly) the aerial defense of the Third Reich; and the RAF, which was dominated by Bomber Command’s obsession with destroying Germany’s industrial base and sapping the enemy’s public morale, such that only after 1935 did Fighter Command begin to gain more resources for short-range defense of the homeland. The Third Reich’s allocation of aircraft resources was at least understandable, if one assumed (as the German generals and admirals did) that Hitler’s conquests would be on land and that the Fuehrer’s diplomacy would keep
the British Empire neutral. The Royal Air Force’s preferences were disastrous for an island nation so dependent for its survival upon long-range oceanic commerce. In 1939, not only was the Fleet Air Arm limited in that it could not specify aircraft suitable for carriers, as the American and Japanese navies could, but RAF Coastal Command—charged to patrol the maritime routes from land bases—was pretty much a Cinderella service compared with the aerial resources being lavished elsewhere.

By contrast, at the middle level, at least on the British side, there was extraordinary initiative as the importance of airpower at sea slowly grew. The brilliant and aggressive Peter Gretton writes in his memoirs about Coastal Command officers attending naval exercises, even a full ocean passage from the Clyde to Newfoundland, and of Royal Navy captains being taken aloft—he claims to have flown in every patrol aircraft type available between 1940 and 1943. But how much did this valuable experience count for if the aircraft squadrons were not there to be deployed? To Air Marshal Harris, appointed to be C in C of Bomber Command in June 1942 with the specific task of increasing the aerial campaign against German industry, diverting his precious long-range bomber squadrons to Coastal Command (i.e., to the Battle of the Atlantic) was, as he put it many times, “picking at the fringes of enemy power … looking for needles in a haystack.”
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Only immense pressures from the Chiefs of Staff compelled some reallocation; in that respect, General George Marshall and even King were a lot more appreciative than Harris of the dire need to get VLR aircraft into the Atlantic air gap by spring 1943. Doenitz had no such luck, at least not until the Fuehrer ordered additional Luftwaffe support for the Bay of Biscay battles later that year.

Closing the air gap did not happen because some great person decreed it. There was the team of chiefly Canadian air engineers who in early 1943 pulled one bomb bay from a B-24 Liberator, replaced it with extra fuel tanks, and at last created an aircraft that could reach the transatlantic gap. There were the scientists who designed the much more effective fuses for Allied depth charges, so they exploded more predictably. There was the combination of U.S. scientists and armaments manufacturers who produced the air-launched acoustic homing torpedo—nicknamed “Fido”—specifically to search for and destroy
submerged enemy submarines.
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There were the groups behind the increasing effectiveness of the HF-DF detectors. There were the designers of the ungainly but wonderful
Bogue
-class escort carriers, and the management teams at the Tacoma yards that accelerated their launchings at a critical time. Finally, there were the staffs of the formidable training schools in Scotland, Northern Ireland, and Newfoundland, who taught thousands of raw, civilian novices how to become professional aircrews and assume such grave responsibilities in the midst of a ferocious Atlantic battle.

In the early stages of the war, it was a rare event for a land-based aircraft to sink a U-boat, and there were no escort carriers at hand. From 1943 onward, aerial sinkings of German and Italian submarines rose spectacularly and steadily overtook those credited to Allied warships. Between June and August 1943, when the U-boats abandoned the North Atlantic and fanned out to prowl the seas off Zanzibar and Montevideo, they were followed by the Liberators and Catalinas. Seventy-nine submarines were sunk by hostile action in distant waters in late 1943, fifty-eight of them by Allied aircraft. Even in the middle of the Indian Ocean, there was no escape. During 1943 as a whole, 199 U-boats were sunk altogether, 140 of them by Allied aircraft, a proportion that would continue for much of the rest of the war.
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This leads us, then, to the destruction aspect. From the German perspective, only one weapons system mattered—the torpedo. It was and may still be the most ubiquitous and destructive naval weapon in modern times. Torpedoes could be fired by small craft, by large craft, by all sorts of aircraft. During the epic
Bismarck
chase, the battleship was crippled by a torpedo dropped by a Swordfish biplane, attacked all night by British destroyers launching torpedoes, and eventually finished off by the torpedoes of the heavy cruiser HMS
Dorsetshire
. Above all, this was the weapon of the submarine. Every modern torpedo was usually powerful enough to blow a hole in the side of an enemy vessel. Normally, this projectile had speed enough to prevent its being deflected or stopped during its drive. Once a U-boat got close enough to a convoy to fire off a salvo, its destructive possibilities—as we have seen—were enormous. Thus the key task for convoy escorts, whether surface or aerial, was to prevent enemy submarines from launching their torpedoes at the flock of merchantmen in the first place. The later
introduction of acoustic or homing torpedoes, or of much more sophisticated U-boats near the end of the war, did not alter that basic fact.

The chief Allied counterweapon, the depth charge, was a less reliable tool of war, at least in its early stages. To begin with, it was not a contact explosive. The theory, which was quite plausible, was that if these large drum-shaped devices could be dropped roughly in the area where a submarine had been detected, their explosive force (magnified by being underwater) would rip apart a U-boat’s joints. It was an attractive weapon because a depth charge launcher could be mounted on the rear deck of even small craft, such as corvettes, cutters, and sloops, as well as the larger destroyers and frigates. It was also of course the chief weapon of all of the antisubmarine aerial patrols (until later in the fight, when they could also drop acoustic torpedoes). Its major disadvantages were swiftly recognized as the conflict unfolded: a warship had to steam over the spot where a submarine had been detected, and that might give an alert U-boat commander time to dive deep (and it took the Admiralty a long time to appreciate just how fast and deep a submarine could dive); the proximity fuses needed to be set at the last moment, according to the U-boat’s estimated depth; and the underwater explosions distorted the asdic readings. Nonetheless, to all submariners the depth charge was the most terrible weapon; waiting for the next crashing noise—and the hunt could go on for days—was an unbelievably stressful experience. Overall, and despite the fact that on average hundreds of depth charges were needed to sink a submerged U-boat, this was the basic destroyer of submarines because it was used throughout the war, by aircraft as well as warships, and because its efficiency was improved over time.
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