The Impact of German Technology on the Royal Canadian Navy in the Battle of the Atlantic, 1942-1943
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The Impact of German Technology on the Royal Canadian Navy in the Battle of the Atlantic, 1942-1943 Robert C. Fisher The Royal Canadian Navy (RCN) destroyed five German U-boats in two months during the summer of 1942, after sinking only two enemy submarines in the first three years of the war. Canadian anti-submarine escorts then hit a dry spell, which lasted almost four months before they sank their next U-boat. To date, this brief period of success has been thought of largely as a coincidence or something of an anomaly. Many naval historians have observed this phenomenon but no one has adequately explained the reason for this brief surge in sinkings by the RCN, or considered the implications of German technologi• cal advances for Canadian warships. Joseph Schull's The Far Distant Ships, a popular history of the RCN during the Second World War, devoted eight pages to the "summer successes, " but glossed over the period of failure from September-December in two pages.1 Tony German's survey history of the RCN provided more balanced treatment but offered no explanation for the downturn in its fortunes after the summer kills.2 Marc Milner's North Atlantic Run observed that in September the Canadian escort groups' record "of at least balancing losses with U-boat kills came to an end. " But this seminal book was primarily a study of convoy and escort policy and operations rather than U-boat sinking and did not speculate on the reasons behind this turn of events. Instead, Milner demonstrated the impact the lack of U-boat kills and the heavy losses of merchant ships in Canadian-escorted convoys had on British decision-makers.3 His following book, The U-boat Hunters, is a study of U- boat killing, but is almost exclusively focused on the last two years of the war. It does not deal with the summer and autumn of 1942 in depth.4 Looking at this period from the perspective of sinking U-boats rather than convoy defence — still the escort's primary task at this stage — reveals that the period of failure from September to December 1942, when the RCN did not sink a U-boat, was in fact the anomaly. This challenges the conventional wisdom. The predominant factor in assessing patterns in U-boat sinking by the RCN is the degree of contact between Canadian warships and enemy submarines. This is directly related to two variables: the number of U-boats and escorts at sea, and their geographical deployment. Obviously, if there were not many U-boats at sea and they were operating in different theatres from Canadian naval forces, the latter would have few opportunities to sink them. The Northern Mariner/Le Marin du nord, VII, No. 4 (October 1997), 1-13. 2 The Northern Mariner This last scenario existed from the outbreak of war until the summer of 1941. The RCN started the war with only six destroyers and the corvette building program took some time to get on track. The U-boat fleet was also small. Still, the destroyers were deployed overseas in the thick of the action after the fall of France in June 1940. This led to the RCN's first kill - shared with HMS Harvester - in November 1940. HMCS Ottawa did not receive credit for sinking the Italian submarine Faa di Bruno until forty years after the fact.5 This kill was an exception. Few Canadian escorts encountered enemy submarines before the autumn of 1941. The lack of more tangible results during the first two years of war can largely be attributed to the relatively small number of RCN warships engaged in anti-submarine warfare. During 1941 new construction began to increase the size of the German U-boat fleet, while the first corvettes increased the size of the RCN dramatically. The RCN had thirteen corvettes at the beginning of 1941, but their number had risen to sixty-six by the end of the year. The Germans had twenty-one U-boats available for operations in February 1941, but by the end of the year the number had increased to ninety-one. Evasive routing based upon special intelligence kept Allied convoys safely clear of the wolf packs through much of 1941. While there were few chances for the new escorts to attack and sink U-boats, this changed in September and October 1941 when a series of convoy battles gave the RCN corvettes their first taste of action on a large scale. The passage of convoy SC 42 — though otherwise a disaster with the loss of sixteen merchant ships — produced the first confirmed U-boat kill for the RCN. HMCS Chambly and Moose Jaw sank U-501 as they joined the convoy to reinforce the close escort. The sinking represented a remarkable achievement for the inexperienced corvettes, but the feat was not soon duplicated: the Canadian escort groups of September and October 1941 were too small — usually only one destroyer and three corvettes — to hunt U-boats to a kill.6 Furthermore, changes in the deployment of U-boats in late October 1941 kept them well clear of the RCN. German U-boats operated mainly in the Mediterranean and Gibraltar theatres during the last two months of 1941, providing the RCN with little opportunity to atone for the defeat of SC 42 or to duplicate its success in sinking U-501. Enemy submarines moved into the coastal waters of the western hemisphere in early January 1942 as part of Operation Drumbeat. For several months, they operated close inshore from St John's, Newfoundland, south along the US eastern seaboard to the Caribbean Sea. The U-boats preyed on the abundant independent shipping, avoiding encounters with escorts and convoys at all costs.7 Thus, despite increasing numbers of Canadian escorts at sea, not to mention the growing U-boat fleet, the RCN had little chance to prove itself during the first half of 1942. The creation of convoys off the North American coast and in the Caribbean Sea left U-boat Command no choice but to resume attacks on convoys. The Germans began wolf pack operations against transatlantic convoys again in July 1942 and, as well, made half-hearted attempts to attack coastal convoys.8 The resumption of wolf pack operations produced an almost continuous string of convoy battles between July 1942 and May 1943, when Allied forces ultimately defeated the wolf packs. The RCN destroyed five U-boats in the space of six weeks in the summer of 1942 to begin this campaign. The first kill, U-90, was by HMCS St Croix on 24 July with the westbound convoy ON 113. HMCS Skeena and Wetaskiwin destroyed U-588 one The Impact of German Technology 3 week later with convoy ON 115. HMCS Assiniboine rammed and sank U-210 with the eastbound SC 94 on 6 August. HMCS Oakville and an American aircraft sank U-94 in the Caribbean Sea on 28 August with convoy TAW 15. The fifth kill, U-756, was by HMCS Morden on 1 September with SC 97.9 There were no patterns apparent in the five kills, which were made both at night and by day, by both destroyers and corvettes, and by both professional and reserve escort captains. The means of detection included eyesight, asdic, and radar. The means of destruction included both ramming and depth charges. The victims included both inexperienced and veteran U-boat commanders. All the killers, however, formed part of the close escort of a convoy. After the sinking on 1 September by HMCS Morden, the RCN did not sink a single submarine for almost four months. This was not for a lack of opportunities, in contrast to the dry spell before the summer of 1942. During the autumn, Canadian escort groups defended several convoys against huge wolf packs. German U-boats torpedoed eleven merchantmen from ON 127 in September and fifteen merchant ships from SC 107 in November. In addition, several minor convoy battles, such as SC 100, HX 212, ON 137 and ON 139, placed the RCN at the forefront of the action. The quality of defence provided by the Canadian escort groups varied greatly from battle to battle. In some cases the escort had to abandon promising contacts after only a few attacks to protect the endangered convoy. Still, the frequent engagement with the enemy provided numerous opportunities for counter-attacks. Yet Canadian naval escorts did not sink a single U-boat until HMCS St Laurent destroyed U-356 on 27 December during the battle for ONS 154. German U-boats torpedoed fourteen ships from ONS 154, making it another disaster for the RCN. But it was also a turning point in terms of U-boat kills, which has often been overlooked by historians because of the magnitude of the losses, and perhaps because the exact identity of the killer was not clearly known until after the war. The sinking of U-356 by St. Laurent kicked off another period of success for the RCN in its boom or bust cycle of anti-submarine warfare. It was the first of six enemy submarines sunk by Canadian warships in less than three months and marked the end of the drought. Next, HMCS Ville de Quebec destroyed U-224 on 13 January 1943 and four days later HMCS Port Arthur sank the Italian submarine Tritone. HMCS Regina followed these two quick kills by sinking another Italian submarine, Avorio, on 8 February. HMCS St. Croix and Shediac destroyed U-87 on 4 March — the second kill for St Croix — and HMCS Prescott destroyed U-163 on 13 March.