Inferno - Max Hastings [175]
In the course of the entire war, while 6.1 percent of Allied shipping losses were inflicted by surface raiders and 6.5 percent by mines, 13.4 percent were caused by air attack and 70 percent by U-boats. The British suffered their first severe blow in the autumn of 1940, when the slow eastbound Atlantic convoy SC7 lost 21 out of 30 ships, and 12 out of 49 were sunk in the fast HX79. Thereafter, the tempo of the undersea war rose steadily: during 1941, 3.6 million tons of British shipping were lost, 2.1 million of these to submarines. Churchill became deeply alarmed. His postwar assertion that the U-boats caused him greater anxiety than any other threat to Britain’s survival has powerfully influenced the historiography of the war. It is scarcely surprising that the prime minister was so troubled, when almost every week until May 1943 he received loss statistics that represented a shockingly steady, debilitating depletion of British transport capabilities.
But the submarine force commanded by Dönitz was weak. Germany’s prewar industrial planning envisaged a fleet which achieved full warfighting capability only in 1944. Naval construction was skewed by a focus on big ships: a hundred U-boats could have been built with the steel lavished on the Bismarck. On the eve of war, Adm. Erich Raeder, German naval C-in-C, wrote: “We are not in a position to play anything like an important part in the war against Britain’s commerce.” Until June 1940, Dönitz did not anticipate waging a major campaign in the Atlantic, because he was denied means to do so; the small, short-range Type VII U-boats that dominated his armoury were designed to operate from German bases. Even when the strategic picture radically changed with Hitler’s seizure of Norway and of France’s Atlantic ports, the Kriegsmarine continued to build Type VIIs. Productivity in German shipyards, hampered by shortages of steel and skilled labour, and later by bombing, fell below British levels. U-boats remained technically primitive. Innovation—for instance, the 1944–45 snorkel underwater air-replenishment system—was not matched by reliability: the revolutionary Type XXI sailed on its first war patrol only on 30 April 1945.
Thus, Dönitz’s force lacked mass, range and quality. Just as the Luftwaffe in 1940–41 attempted to deal a knockout blow to Britain with wholly inadequate resources, so the U-boat arm lacked strength to accomplish the severance of the Atlantic link. Germany never built anything like enough submarines to make them a war-winning weapon. Dönitz calculated that he needed to sink 600,000 tons of British shipping a month to achieve a decisive victory, for which he required 300 U-boats in commission to sustain a third of that number in operational areas. Yet only 13 U-boats were on station in August 1940, falling to 8 in January 1941, rising to 21 the following month. This small force inflicted impressive destruction: 2 million tons of British shipping were sunk between June 1940 and March 1941. But in the same period just 72 new U-boats were delivered, far short of the number Dönitz needed. They achieved their highest rate of productivity—measured by tonnage sunk per submarine at sea—in October 1940; thereafter, while many more boats were deployed, their pro-rata achievements diminished.
As the war developed, while the Allied navies grew apace in skill and professionalism, the quality and determination of U-boat crews declined. One by one Dönitz’s aces were killed or captured, and the men who replaced them were of lesser calibre. German torpedo technology was almost as flawed as that of the 1942–43 U.S. Navy. Direction of the U-boat campaign was hampered by changing strategies and impulsive interventions by Hitler. German naval intelligence and grasp of Allied strategy, tactics and technology were chronically weak.
It is a remarkable and important statistic that 99 percent of all ships which sailed from North