Canada and Submarine Warfare, 1909-1950
Roger Sarty
The German Submarine Offensive Makes Canada a Major Maritime Power, 1939-1945
Germany had already positioned its sea-going submarines in the western approaches to the British Isles, and one of these sank without warning the unarmed liner Athenia on 3 September, the day the United Kingdom declared war. 35 With this apparent evidence that the Germans were launching unrestricted submarine warfare, Winston Churchill, First Lord of the Admiralty, immediately ordered the implementation of ocean convoy. In accordance with the Anglo-Canadian plans, RCN control of shipping staffs had begun to take up position at major ports since late August -- two weeks before Canada's declaration of war on 10 September. The Canadian staff at Halifax despatched the first east-bound convoy, HX-1, on 16 September. Until after the United States entered the war in December 1941, Halifax was the principal convoy port in the Western Hemisphere. 36
The principal task of the RCN destroyers, together with Eastern Air Command's single squadron of flying boats, was to provide anti-submarine escort for the convoys through the 300-400 mile approach zone off Halifax. As in the First World war, major British warships continued the escort to guard against German surface raiders at mid-ocean, and then British anti-submarine vessels and aircraft joined as the convoy neared the U-boat operating area in the western approaches to the United Kingdom.
Nelles believed that the events of 1915-1918 would repeat themselves but more quickly this time. As defences tightened in the eastern Atlantic, the U-boats would come west in search of easier targets. He therefore pressed for a large-scale emergency construction program to produce the anti-submarine and minesweeping vessels needed to screen ocean convoys as they formed up and to escort coastal shipping. Yet he also argued, with nothing less than passion, for Tribal destroyers. These sophisticated ships, he admitted, could not be completed for some years and it would take an equally long time to train efficient crews for them.Revealingly, his arguments centred not on the present conflict, but on the past and the future. Canada had run a risk by not having such powerful warships in the 1930s, and must now procure them as the foundation of a permanent fleet that would serve Canada in the uncertain post-war future. For the short term, he wanted three passenger ships, Prince Robert, Prince Henry and Prince David immediately converted into armed merchant cruisers. Like the Tribal program, the Prince ships scheme was insurance that the RCN did not, as in the First World War, become an exclusively small ship force, ingloriously employed and therefore subject to debilitating cuts on the return of peace.37
Ambitious naval expansion now nicely coincided with the government's priorities, the most important of which was to avoid overseas conscription. Borden's government had alienated Quebec in 1917-1918 by introducing compulsory service to replace the heavy casualties in the overseas army corps; King had secured his power base in French Canada by pledging that he would never follow suit. Not only were naval manpower needs modest as compared to those of the other services, but it also seemed that the RCN would largely operate in North American waters. The naval program's requirement for a substantial industrial effort, moreover, fulfilled the prime minister's determination that Canada's contribution should be economic rather than the supply of cannon-fodder.
With King's personal intervention, the government approved Nelles's proposals during the winter of 1939-1940. 38 Most notably, cabinet authorized escort construction to the maximum capacity of Canadian industry 92 corvette anti-submarine vessels and Bangor class minesweepers. These new British designs were larger and more capable than the existing trawler types of the auxiliary fleet, but simple enough that they could be produced by inexperienced yards. Because the Tribal destroyers could not be quickly produced in Canada under wartime conditions, the orders were placed in Britain. 39
Thus, during the early months of 1940, the RCN was able confidently to look forward to an orderly expansion, firmly rooted in pre-war plans. The projected strength of some 15,000 personnel by the end of March 1943 40was not an unreasonable growth from the 3,700 regulars and reservists who had been available in August 1939. There were no doubts that the Anglo-French fleets could hold the ring in European waters; the RCN would carry out, more adequately than in 1915-1918, anti-submarine defence in the north-west Atlantic, and relieve the Allied fleets of a measure of the responsibility for defence against surface raiders in the western hemisphere.
These assumptions were blown apart by the German offensive in the west in the spring of 1940. At the end of May, as France collapsed and it seemed Britain herself would soon face invasion, four RCN destroyers -- all of the ones not in need of refit -- crossed the ocean. 41 After assisting in the evacuation of Allied forces from France, the ships were committed to anti-submarine convoy escort in the Western Approaches. There were only about 30 U-boats available for operations, but access to French Atlantic ports multiplied the effectiveness of the force: boats had no longer to make the long passage from the Baltic through the North Sea where they had previously been harassed and delayed by British air and sea patrols. During the fall of 1940, the 'Happy Time' for the U-boats, British shipping losses soared to 50 and more vessels per month. Most of these were ships that sailed independently, but, worryingly, the Germans were beginning to concentrate 'wolfpacks' of boats to overwhelm convoy defences.42
Britain's need and the increased danger of attacks in Canadian waters forced acceleration and expansion of the RCN's program when the program had scarcely got started. In the fall of 1940, the RCN responded to the Admiralty's pleas by manning six -- and later a seventh -- of the 50 obsolescent ('Town' class) destroyers the United States transferred the Royal Navy. The first ten corvettes under construction in Canada and been allocated to Britain, but when these completed at the end of 1940, the Admiralty asked that Canada should man these as well. All told, the RCN had quickly to find 2000 additional seagoing personnel, and this was just the beginning of burgeoning new commitments. By the end of 1941, the RCN had reached a strength of 30,000 personnel and was manning the three 'Prince' armed merchant cruisers, thirteen destroyers and 91 Canadian built corvettes and Bangors in addition to many smaller warships and auxiliaries.43
The largest new undertaking resulted from the extension of U-boat attacks westward towards Newfoundland as defence measures in British waters became more effective. Beginning in May 1941 Canada supplied the bulk of the vessels for the new Newfoundland Escort Force (later, Mid-Ocean Escort Force) which protected convoys between St. John's and Iceland (later, Londonderry, Northern Ireland). All of the RCN destroyers (both the pre-war fleet type and the ex US 'Towns') and corvettes that had been serving in British waters were allocated to the force, as were most of the corvettes that completed during 1941. 44 One result of the mid-ocean commitment was to isolate the RCN from British refit and training bases -- facilities at St. John's and Iceland were minimal, and those at Halifax over-crowded and over-extended -- at the very time the Royal Navy was installing new equipment such as short-wave radar on its escorts and developing co-ordinated group tactics to counter wolfpack attacks on convoys. 45 RCN isolation from the Royal Navy became more profound in September 1941, when the United States Navy -- which had no recent experience of anti-submarine warfare -- began to escort shipping to Iceland and assumed control over trade defence in the western Atlantic.46
The RCN's ill-equipped, ill-trained mid-ocean force did not have an easy initiation into war on the high seas. British decryption of German naval radio signals (to produce what was known as 'ultra' intelligence), enabled shore authorities to route most convoys clear of danger. 47With their diminishing success in finding shipping, however, the U-boats adopted more dispersed search formations. These had their greatest success in locating the slow series of convoys, which made speeds of not much better than seven knots at best, for which the RCN mid-ocean groups were primarily responsible. To make matters worse, in the fall of 1941 the British had ended a recent practice of combining two convoys to have the advantage of a double-size escort out of a false fear that the combined convoys were becoming too large and vulnerable. As a result the four RCN-escorted convoys that suffered substantial losses faced the initial attacks with small groups largely comprising the slow, inexperienced corvettes, and at most only one destroyer, the type whose speed and heavier armament made it the key to a successful defence.48
Although the U-boats were temporarily redeployed to the Mediterranean in November 1941, there was little respite for the Canadian forces. The RCN, in organizing the Newfoundland force, had retained minimal strength in home waters. The RCAF's Eastern Air Command meanwhile was scrambling to develop bases and to provide enough minimally qualified personnel to meet pressing commitments. Modern aircraft, the best from US manufacturers, were just beginning to arrive in anything like adequate numbers in the latter part of 1941. Neither service was prepared when in January 1942 Germany responded to the United States' entry into the war by despatching the first of several waves of U-boats which slaughtered independently routed shipping in North American waters. 49 The United States meanwhile had to remove warships from the north Atlantic to protect its own coastal waters and to reinforce the Pacific. 50 With the help of some British escorts, and by rushing newly completed ships into service, the RCN was able to organize a comprehensive system of coastal convoys, much as it had done in 1918. However, demands on the 'Western Local Escort Force' (later, the Western Escort Force) continued to grow more rapidly than resources. Because the United States was crticially short of escorts, the RCN took responsibility for the escort of coastal convoys from Boston to Halifax, and ran its own tanker convoys to the Caribbean. 51In May, as ice cleared from the Gulf of St. Lawrence, the first of seven U-boats that would hunt there during the shipping season sank two independents, necessitating a further extension of the convoy system through that 600-mile-long inland sea. In September 1942, just as Churchill's personal plea brought the dispatch of 16 corvettes from the RCN's coastal commands to support the 'Torch' landings in North Africa, 52 the two series of transatlantic convoys that had sailed from Halifax and Sydney were transferred to New York.The WLEF now had to escort these convoys over 1000 miles to the vicinity of St. John's where the mid-ocean force took over.
Coastal convoys greatly reduced shipping losses in Canadian waters, but it was still possible for U-boats to take up positions ahead of a convoy through fast surface runs, and then make repeated submerged attacks with little danger of retribution from the poorly trained and equipped escort groups. On 15 and 16 September, for example, U-165 and U-517 were able to sink four ships and damage a fifth in a Gulf of St.Lawrence convoy, despite the presence of no fewer than seven escorts.53
In British waters aircraft of Coastal Command had pushed the U-boats out of vulnerable inshore waters more than a year before by concentrating air patrols in areas where naval intelligence suggested U-boats were located. These aircraft made wide-ranging sweeps over the entire vicinity at high altitudes that tests revealed gave the greatest efficiency for radar and visual surveillance. Soon it proved impossible for submarines to locate and pursue shipping with fast surface runs. In early 1942, moreover, as Coastal Command belatedly overcame failures in weapons and attack procedures, aircraft began to inflict heavy losses on U-boats. By contrast, Eastern Air Command (and the US air services) were still trying to fly close, low-altitude, cover over all convoys. One highly motivated squadron commander, Squadron Leader N.E. Small, began to use the new British methods in July 1942 with dramatic results, including the destruction of a U-boat off Yarmouth, but it was not until October that the whole of the command adopted the improved tactics.
By that time, the strengthened defences on the North American coast had brought Admiral Karl Doenitz, commander-in-chief U-boats, to concentrate his fleet at mid-ocean, for an all-out wolfpack assault on the main transatlantic convoys. Here, beyond the reach of Allied air power, the boats could move freely on the surface to track and concentrate against convoys; the increasing numbers of U-boats available and the Allies' loss of 'Ultra' intelligence after the German navy had adopted an improved cipher machine earlier in the year gave further advantages. 54 Eastern Air Command's new tactics delivered a nasty surprise at the end of October, when within the space of a few hours aircraft sank two of 15 submarines on the ocean route east of Newfoundland. Because the RCAF possessed no machines that could reach much beyond 400 miles, however, the boats were able during the following days to mass against the eastbound convoy SC-107. The Canadian escort, typically for the period, lacked cohesion because of recent changes in the ships allocated to the group. Excessive commitments and inadequate repair facilities meant that the only way to keep escort groups up to minimum strength was constantly to shift ships between them, making it impossible for the groups to become well-coorindated teams of the kind needed to screen the long perimeter of a convoy at night against an increasingly numerous enemy. Most of the ships also lacked the shortwave radar that was necessary to detect fast-moving, surfaced U-boats, and high-frequency direction finding equipment with which U-boats could be located by their signals as they pursued the convoy. On 1-4 November, the submarines sank 13 merchant ships without loss to themselves. This disaster confirmed a pattern of heavy losses by Canadian escorted convoys. The Battle of the Atlantic had shifted to a new phase in which advanced technology and rigorous training of cohesive, permanently organized escort groups gave the essential edge: during the winter of 1942-1943 NSHQ agreed to the Admiralty's advice that the RCN's four mid-ocean groups should be withdrawn to European waters to re-equip and train at British establishments.Thus it was the British escort groups, and especially the recently formed support groups of the most capable escort types that ranged the sea lanes ready to assist threatened convoys, that urned the tide against the U-boats in the pitched battles of early 1943. 55
The Canadian groups, however, were never entirely absent from the north Atlantic during the critical early months of 1943. Because of the need for additional warships to replace casualities to enemy action and to the particularly ghastly weather that winter, one of the groups never left for the eastern Atlantic, and the other three spent only half of the four months there that had originally been intended. Operational pressures, moreover, allowed less training time than had been planned for the three groups that did serve in the eastern Atlantic. Nevertheless, with benefit of the improved equipment, especially micro-wave radar, that was fitted at British bases, the three groups acquitted themselves well escorting convoys from the United Kingdom to Gibraltar in support of the Allied offensive in North Africa. They destroyed or shared in the destruction of two enemy submarines and two aircraft. Meanwhile, the 16 RCN corvettes that had been earlier committed to the North African operations and also received updated equipment and some refresher training destroyed three submarines. This impressive record suggested there was nothing fundamentally wrong with Canadian ships and crews if they were given proper support.56
RCN officers most closely in touch with the fleet realized that essential support had been all but non-existent during 1942. The country's limited resources had been entirely committed to getting as many escorts to sea as quickly as possible to the virtual neglect of the development of the facilities needed for proper training and the periodic refit of the vessels with the most advanced equipment. As it was, crushing operational schedules denied the layovers essential to rest the crews and allow even such repair work and refresher training as was possible with the limited facilities available. Senior officers also knew that much of the difficulty arose from the Canada's can-do spirit. British and American anti-submarine forces had been able to perfect tactics, refit with new equipment, and train in large measure because the RCN had pulled itself in all directions during 1941 and 1942 to cover off the shortage of escorts in the main Allied fleets.
The events of the winter of 1942-1943 confirmed the need to consolidate the Canadian naval effort. The most notable result of the naval staff's hard bargaining with its Allied counterparts was the creation on 30 April 1943 of a distinct Canadian command in the north-west Atlantic. The Canadians successfully argued that US control in the theatre was now an anomaly -- the Americans supplied two percent of the north Atlantic escorts, as compared to the RCN's forty-eight per cent -- and needlessly confused command arrangements. 57 The Canadian anti-submarine force gained strength with the transfer from the Royal Navy in 1943 to early 1944 of six 1930s-vintage destroyers well suited to escort work, and the delivery from Canadian yards starting in late 1943 of frigates. These were purpose built ocean escorts, larger and faster than the little corvettes that had never been intended for high seas work. 58 Meanwhile, in the spring of 1943, Eastern Air Command finally won its campaign for allocation from American production of four-engine 'very-long-range' bombers that could intersect with RAF patrols from Iceland and close the lethal 'air gap' over the convoy routes. 59 In fact, in September 1943 the Canadian Liberator squadron, No 10 (Bomber-Reconnaissance), based in Gander, Newfoundland, made transatlantic flights from both sides of the ocean to support the embattled convoy ONS 18/ON 202, destroying one U-boat and damaging several others. Admiral Doenitz had hoped to revive pack tactics at mid-Atlantic with the attack on this convoy, but the appearance of the strong very-long-range air coverage did much to convince him that the effort had failed. 60
Prior to September 1943, the RCN had destroyed or shared in the sinking of 14 submarines: during the following twelve months Canadian ships equalled that score. This performance compared favourably with that of the much larger Royal Navy escort forces which sank or shared in the destruction of 70 boats during the same period. Also outstanding were the results obtained by Eastern Air Command and three RCAF squadrons that had formed in RAF Coastal Command (very sensibly, the home and overseas maritime squadrons began to exchange experienced personnel during this period). Together they destroyed or shared in the destruction of six prior to September 1943 and 11 more during the following year. 61
During 1944 the expanding Canadian anti-submarine forces played an extremely important part in the Normandy landings and follow up operations. In the months before the landings, the RCN accepted full responsibility for the escort of north Atlantic convoys to release British warships for the invasion force. At the same time, the Canadian service diluted its escort forces to provide ten escort destroyers, 12 frigates and 19 corvettes to provide anti-submarine defence to the invasion flotillas. Further British appeals for assistance brought the reconversion of 18 Bangors on escort service on the Canadian coasts into minesweepers. 62 These vessels helped clear the mine-infested waters ahead of invasion ships before dawn on D-Day. In the English Channel during the weeks following the landings, one of the destroyer groups sank three U-boats that were attempting to interdict supply of the armies. Meanwhile off Norway, Eastern Air Command's 162 Squadron, which had been loaned to Coastal Command, sank four U-boats and shared in the destruction of a fifth during the single month of June 1944.
These successes were at least partly due to the fact that in the eastern Atlantic U-boats were still manoeuvering on the surface in an effort to strike into the main shipping lanes. On the western side of the ocean, Canada's own command -- the Canadian Northwest Atlantic theatre under Rear Admiral L.W. Murray, RCN, at Halifax -- was fighting a very different kind of war. It was here, during the fall and winter of 1943, that U-boats began to employ 'guerilla' tactics, penetrating inshore waters with long submerged runs and then lying beneath the surface awaiting targets of opportunity. Improved radar detectors allowed the boats ample time to dive before registering firm contacts on Allied shipborne and airborne equipment. Strict radio silence neutralized the efficient Allied radio direction finding network. These measures effectively countered the Allies principal methods of U-boat location. Asdic's range was limited in the best of conditions, but was often virtually nil in the extremely difficult hydrographic conditions close in to the Canadian and Newfoundland coasts. 63
Favouring the Allies was 'ultra' intelligence. After a blackout during most of 1942 as a result of the German navy adopting a more sophisticated cypher, Allied intelligence again made a 'break in' and by the fall of 1943 was reading much of the traffic with only a few hours' delay. Naval Service Headquarters immediately received the latest decryptions from Washington and London. 64 With this information, Eastern Air Command -- now a formidable organization of over 20,000 personnel and over a hundred major anti-submarine aircraft -- was able to surprise, and paralyze, two of the early intruders with four near miss attacks. 65 Those boats, however, had dared to make long runs on the surface: the ones that followed seldom surfaced except at night. From the spring of 1944, all boats that came into Canadian waters were schnorkel equipped and remained submerged for the whole of their six-week missions in the coastal areas showing only the tip of the breathing tube which could not be located by radar in the rough seas. Ultra gave only the general course and destination of a boat -- not enough to make an actual location -- but Eastern Air Command was able to harass the boats by constantly overflying areas where they were most likely lurking. 66 Harassment, however, was not effective with bold submariners and three of them, Klaus Hornbostel of U-806, Hans Reith of U-190, and, especially, Kurt Dobratz of U-1232, were able to penetrate close in to the mouth of Halifax harbour where they destroyed five merchant vessels, severely damaged a sixth and sank two Bangor minesweepers between 24 December 1944 and 16 April 1945. All escaped massive air and sea searches, as had the other boats that operated in Canadian waters during the last year of the war.67
Losses inflicted by U-boats in the Canadian zone after September 1943 were minor. More than two dozen boats sank or damaged only 16 ships, as compared to the 1942 campaign in which the seven boats that had operated in the St. Lawrence alone sank or damaged two dozen vessels. The failure of the Canadian forces to destroy any of the intruders in 1943-1945, however, was the result of something more than the miserable operating conditions. Hunting for 'guerilla' boats required intimate air-sea co-operation that had never been achieved in the Canadian zone. Before the war the British government had placed the RAF's Coastal Command under the direction of the navy. Naval and air commanders responsible for a particular maritime area, moreover, shared a common operations room where they worked from the same intelligence plots. The RCN and RCAF steadfastly refused to follow this lead. Both were small, new services whose foundations were as yet insecure and they jealously guarded their independence. Not until early 1943 did the RCAF accept naval direction, and even then it took sharp criticism from visiting British and American experts finally to persuade the services to establish a combined operations room at Halifax. 68
Moreover, the navy's home waters forces, although not as thinly stretched as in 1942, suffered from similar shortcomings. Quite properly NSHQ gave priority in the allocation of frigates and the destroyers to the offensive against the U-boats in the eastern Atlantic, the build-up for the Normandy invasion, and finally, to the defence of British home waters when in the fall of 1944 the Germans began a guerilla campaign there with schnorkel boats. Of the 54 RCN frigates operational in January 1945, for example, 43 were allocated to the mid-ocean force and to British waters; the 11 available to Admiral Murray were all recently commissioned, inexperienced ships. Murray had to rely heavily on the older corvettes and Bangors, which by this stage of the war were unsuited to active hunting. 69
The somewhat paradoxical result was that Canada's 'national' maritime command depended for striking power on the US Navy, which now had surplus of destroyer escort and escort aircraft carrier groups. From the summer of 1944, strong American forces were usually assigned to track incoming submarines when Ultra revealed that they were heading from mid-ocean into Canadian waters. These superbly equipped and trained task groups destroyed three submarines in the Canadian zone -- although all them were in deep water well out from the from the coast where asdic conditions were impossible. 70
In British waters, RCN frigate hunting groups destroyed four U-boats after September 1944, but this marked a sharp falling off in performance from the previous twelve months. By contrast, British groups killed or shared in the destruction of 36 boats in the period October 1944-April 1945. Significantly, most of the British kills were made by ships equipped with the latest 'Squid' anti-submarine mortars and associated new types of asdic equipment that represented a quantum leap ahead of the weapons and detectors in most Canadian ships. As Marc Milner and David Zimmerman 71 have suggested, the technical shortcomings of the frigates showed the persistence of problems that had contributed to the crisis of 1942-early 1943: the difficulty of creating a Canadian industrial base, where virtually none had existed prior to 1940, and the failure of the naval staff owing to a dearth of qualified technical officers to identify rapidly changing requirements and communicate them effectively to research agencies and industry.
Less susceptible of systematic analysis and documentation is the effect of a continued tendency among senior officers to regard anti-submarine as a distraction from the central objective of creating a balanced fleet. Opportunity knocked in 1943 when manpower shortages forced the Royal Navy to offer major warships to the RCN, and Allied planning began for increased Commonwealth naval participation in the war against Japan. Determined not to be restricted to the anti-submarine role in the Pacific, the RCN's intention was to take over four cruisers, two light fleet carriers and additional fleet destroyers from the RN to form a surface warfare task group. This group would then become the basis for the permanent post-war fleet. Before the sudden end of the Pacific war, the RCN had taken over two fleet class destroyers, which, together with the four Tribals, saw extensive action in European waters, and two cruisers, one of which arrived on the Pacific in time for operations. In addition, the Canadian service manned two Royal Navy escort carriers in the European theatre as preparation for the transfer of light fleet carriers. 72
