The British could reasonably have supposed that with the United States fully in the war, the situation in the Atlantic would improve, but the Americans were far less ready for war than expected. So, as disastrous as war with the United States proved in the long run, it actually simplified the German Navy’s immediate problems.
As noted earlier, Hitler ordered attacks on American ships even before declaring war on the United States, but the concentration of U-boats in the south and the Arctic left the Germans in a poor position to strike along the American coast. Because Hitler became exceptionally nervous about a British attack on Norway, he ordered more U-boats north in early 1942. In December 1941, Dönitz wanted all possible U-boats—twelve—to go to the American Eastern Seaboard at once. The Naval Staff let him send just five Type IXs. At this point the navy believed that the Type VII U-boats’ range was so short that they could not operate south of Nova Scotia.
The force spread out between the Gulf of St. Lawrence and Cape Hatteras, North Carolina. In mid-January, the U-boats would strike only when all were in position (unless they could attack ships of more than 10,000 tons) to attempt to take advantage of whatever surprise was still possible. They assumed that the attack on the American East Coast would be a temporary diversion from the main battle in the mid-Atlantic and that the Americans would soon organize convoys, making long patrols to their coastal waters unprofitable. This was not the case.
A month had passed since Pearl Harbor, but the Americans took longer to react than expected. As John Waters wrote, had the Germans been fully aware of the Pearl Harbor attack in advance and pre-positioned twenty to thirty U-boats, including minelayers, off the Eastern Seaboard, they would probably have shut down traffic there completely. As it was, the Allies suffered a major disaster. Apart from the fact that ships carrying supplies to Britain usually departed U.S. East Coast ports before joining transatlantic convoys, the American economy depended far more on coastal shipping than was generally realized. No less than 260 of the United States’ 350 large tankers hauled oil from Texas to the East Coast. Other goods also traveled by sea rather than overburden the railroads, which were in bad shape after decades of bad regulation and the Depression.
The astonished Germans found the American coastline well lit, with shipping proceeding in an unorganized, normal peacetime fashion, silhouetted by the lights of towns. They gained useful information from listening to the chatter of the ships’ radios. Cape Hatteras proved an especially good hunting ground. In two weeks after the first attack on January 12, the U-boats sank thirteen ships of 95,000 tons, nearly three-quarters of them tankers. To their astonishment, the massacre went on and on, eliciting only a slight reaction. Dönitz soon reinforced the U-boats off the East Coast and, in mid-February, sent some to the Caribbean. The Type VII boats began pushing farther southwest. By using the most efficient method of cruising and carefully conserving supplies, they could reach the Eastern Seaboard. But the Germans rarely had more than a dozen U-boats there at any one time. Wolf pack tactics were temporarily discarded. The U-boats operated individually, usually on the surface at night, right offshore. American defenses were so poor that they attacked by day as well, sometimes on the surface, and found it possible to use their deck guns, which were normally of little value in World War II.
The Germans did not encounter any convoys, and the American forces were almost totally ineffective. The Americans’ only defensive preparations against the U-boats were minefields in the approaches to New York, Boston, and the Chesapeake Bay, and booms and nets to keep submarines from actually entering New York and some other harbors. Adm. Adolphus Andrews’s Eastern Sea Frontier started the campaign with only seven Coast Guard cutters; three unreliable Ford Eagle boats (poorly built World War I-era antisubmarine patrol craft); four wooden subchasers also left over from the earlier war; two gunboats; and four converted yachts.
The new chief of naval operations, Adm. Ernest King, poorly supported Andrews’s efforts. Able enough in directing the Pacific War, King’s disinterest in the Atlantic struggle and Anglophobia made him a dubious asset in the war against Germany. (General Eisenhower once speculated in the privacy of his journal that if somebody shot King, it would help win the war.) King only belatedly let Andrews shift the regular shipping lanes sixty miles out to sea to make it harder for the enemy to find targets, and King rejected a blackout. Meanwhile, the U.S. Navy showed little interest in British and Canadian experience or the ciphers and procedures the latter had prepared for the Americans’ use. King disallowed an early start of coastal convoys, wrongly believing that poorly escorted convoys were worse than none. Instead of shepherding shipping, Andrews sent the few available destroyers that he occasionally borrowed from other duties out on offensive patrols to hunt U-boats. This tactic proved as useless as it always had against submarines and that led to U-578 sinking the destroyer Jacob Jones on February 28. The navy and U.S. Army Air Force (USAAF) did not collaborate well in providing air cover, and the few aircrews available were poorly trained for work over the sea. (Civilian fliers, acting on their own, had organized the Civil Air Patrol before Pearl Harbor.) King also failed to act on proposals to mobilize small civilian craft in a Coastal Picket Patrol until June 17, after the crisis was largely past. The small craft would have seriously interfered with German operations near the shore. Except around Cape Hatteras, East Coast waters were so shallow that the Germans would not have dared attack near the coast had the defenses not been so incredibly weak. Even less forgivably, the navy broadcast many claims of U-boat kills it knew were false.
Effort and lives were wasted on Q-ships, or converted freighters and trawlers armed with hidden guns to act as U-boat traps. Q-ships had enjoyed some success in World War I. British attempts to revive the idea in the second war had already failed, however; the Germans were too alert for it to work again. The Q-ship Atik was lost with all 161 men aboard. The president had pushed using the Q-ships, but King did not resist the idea. King seems to have been waiting for the arrival of new 110-foot subchasers and 173-foot patrol craft, but the program to build them received priority only in April 1942.
Meanwhile, the shipping losses had caused an adverse public reaction and alarm within the armed forces. The army grew increasingly concerned and angry, and the AAF launched a rival antisubmarine effort that lasted into 1943. The British were furious at losing precious ships in waters that should have been relatively safe. They had to send some of their own escorts to the Caribbean to guard tanker convoys, and King reluctantly accepted the loan of twenty-four British antisubmarine trawlers and later a Coastal Command squadron. The trawlers were mostly slow coal burners that required high-grade coal, were in poor condition, and were unsuited for the Atlantic crossing—one was lost en route to the United States—but as they became operational in March 1942, they proved welcome. By April, the strength of the Eastern Sea Frontier had grown to eighty-four army and eighty-six navy planes, sixty-five Coast Guard cutters, three 173-foot patrol craft, a dozen Eagle boats and converted yachts, and fourteen British trawlers. This larger fleet and the greater caution of merchant ship captains complicated the U-boats’ work. On April 1, the Americans finally started a semi-convoy system, the so-called Bucket Brigades, along the coast. During the day, locally based escort craft herded gaggles of ships close inshore, and the ships halted for the night in protected anchorages—regular harbors or specially mined and protected sites.
Losses, especially of tankers, however, remained so horrendous that the oil industry warned that the United States would run out of tankers by the end of 1942. Finally the disaster became so obvious that on April 16, all tankers were ordered to stay in port until further notice, although a few had special permission to move via Bucket Brigade. Frantic efforts were made to reduce dependence on oil moved by sea. Industries converted many oil-burning plants to coal or natural gas, and disused railroad tank cars and barges were rehabilitated.
By the end of April, ships passed Cape Hatteras only by day and at varying distances from the coast. The Germans perceived that U.S. defenses were at last hardening. They concluded that it was no longer safe to attack near the coast, except on dark nights. On April 14 the destroyer USS Roper sank U-85, the first U-boat destroyed by American forces off the East Coast.
By May, the Germans had eighteen U-boats operating from Newfoundland to Florida and seven more in or near the Caribbean, but in mid-May a true convoy system finally went into effect. That made patrolling the Eastern Seaboard unprofitable. Dönitz shifted the effort to the Gulf of Mexico and the Caribbean, where the opposition remained weak for three more months. The Germans were assisted by the introduction of the first Type XIV supply U-boats—known as the milch cows or U-tankers, they could refuel other U-boats—although only three were available during the American campaign. Italian submarines, which proved surprisingly effective, also joined the Germans. Eventually, however, convoys started in southern waters too, ending the campaign.
In the first seven months of 1942, the U-boats had sunk 609 ships of 3.1 million tons, including 143 tankers, mostly in the Americas. The Allies had lost another 45 tankers to other causes. (By comparison, at the start of the Pacific War, the Japanese merchant marine had 94 tankers and 1,609 passenger and dry cargo ships.) The peak month of June saw the U-boats sink 136 ships of 637,000 tons. Some sources give a slightly higher total of 144 ships of 700,000 tons, which, if correct, made June 1942 one of the few months of the war in which Dönitz attained his self-set target for destroying the Allied merchant marine. All Axis submarines in the months of January through July 1942 had sunk 757 merchant ships and auxiliary naval vessels of 3,773,469 gross registered tons. The Allies had lost 1,120 ships of 4.8 million tons to all causes. Most of these losses were suffered in American waters and, even given the limits of Allied resources, quite unnecessary.
These fantastic losses were only bearable because of the growing success of the American and Canadian shipbuilding efforts, without which the Allies could not have sustained Britain, much less won the war. In 1941, the United States and Canada had begun mass-producing standardized freighters, often in entirely new shipyards using new workers. The American industrialist Henry Kaiser became especially effective and prominent at this effort. He was so successful that, against the navy’s opposition, he persuaded President Roosevelt to let him build escort carriers in the same way with good results.
Most new cargo ships were based on an older British design, the steam-powered Sunderland tramp steamer, which the British had standardized as the Empire Liberty type. The British had had some built as the Ocean class in American and Canadian yards in 1940. The U.S. Maritime Commission altered this design to make it easier both to mass-produce and for inexperienced crews to operate by modifying its engines, rudder, and crew accommodations and specifying all-welded construction, then a novelty. The result was the EC-2 Liberty ship of 7,176 gross registered tons. Usually named for famous Americans, Liberty ships were ugly but effective. They were powered by old-fashioned reciprocating steam engines when turbines and diesels were needed elsewhere. The first of 2,710 Liberty ships, the SS Patrick Henry, was launched on September 27, 1941. Kaiser’s organization built Liberty ships in fantastically short times, and by 1944 it completed Liberties in an average of forty-two days each. In that year, the industry also began to build faster and slightly bigger Victory ships.
During 1942, the American ship construction effort took off, building 646 freighters (597 Liberties) plus 62 tankers and 33 miscellaneous types. In December 1942 alone, American industry produced as many ships as it had in the entire preceding year. In the first six months of 1943, the Americans built 711 ships of 5.7 million tons.
A concurrent Canadian shipbuilding drive was in some ways even more remarkable given the lack of industrial base The Canadians concentrated on their own variant of the Ocean type, the Fort class. Unlike Liberties, they were originally coal burners, although a later version was oil fueled. The first of these ships, Fort Ville Marie, was launched on October 10, 1941, and in all, the Canadians built some 300 vessels.
The shipbuilding effort made it possible for the Allies to replace a good portion of their losses, even in the worst period of the war. From January to August 1942, for instance, 357 new ships of 2,634,000 tons came into existence.
As noted earlier, by the end of 1941, some Germans, including members of Dönitz’s staff, doubted the viability of the U-boat campaign in its present form. The relatively disappointing development of the Atlantic campaign since mid-1941, culminating in the disaster of convoy HG 76, suggested that the Allies already had the counter to the U-boat, and it was only a matter of time until they used it properly. The success in the Americas, never expected to be more than a temporary diversion, lasted longer than they had dared to hope. Dönitz, to be sure, remained optimistic and still thought that enough of the existing U-boat types could compete with the Allied shipbuilding program. That effort impressed even the Germans, although they underestimated its scope.
As he explained to Hitler on May 14, Dönitz thought that sinking 700,000 tons of shipping a month would offset Allied new construction, which he believed would reach 8.1 million tons in 1942 and 10.3 million tons in 1943. (It was a slight overestimate for 1942 but a gross underestimate of the 14.39 million tons that would be built in 1943.) But Dönitz overestimated Allied losses by a great margin. Hitler backed his call for concentrating all shipyard resources on U-boats rather than the more balanced program Admiral Raeder wanted.
The Naval War Staff continued to doubt that Dönitz’s integral tonnage strategy would work, if the rate of sinking (then high) remained the same and the Allied shipbuilding plans succeeded. The staff pointed out that success as had been attained so far in 1942 came from surprise attacks in weakly defended areas, and the rate of success against convoys was expected to fall. It would be necessary to sink not 700,000 tons but 1.3 million tons a month; however, that target was not in prospect. The staff suggested that the U-boats’ aim should be not on destroying tonnage but eliminating cargoes and sinking ships headed to Britain, both immediately around Britain and in the South Atlantic, although it did not fully explain how to accomplish this mission. Cmdr. Kurt Assmann of the Naval Operations Department even suggested that they could not expect victory in the U-boat war, but this conclusion was cut from the Naval War Staff’s final assessment, which it submitted on October 20.
Even Dönitz must have had private doubts about winning with the conventional U-boats. He and others looked for a technical breakthrough. An engineer working in the German Naval High Command, Adolph Schneeweisse, suggested building “underwater assault boats” to attack convoys. He envisioned that Type XB and Type XI U-boats would carry these superfast midget submarines, capable of speeds of 30 knots and armed with two or three torpedoes, to the battle area. But even had the midgets been developed in time to affect the outcome of the war, Germany did not have enough big submarines to serve as “mother ships” for a major campaign. Although these subs might have posed a difficult problem for the Allies, Dönitz had to look for a different solution.
Since the early 1930s the German Navy had backed work on closed-cycle propulsion systems that required no external air supply and would let submarines with radical new hull forms run faster while submerged than on the surface and with speeds comparable to those of surface ships. Such systems used diesel or turbine engines supplied either with oxygen in high-pressure bottles or in liquid form or with a fuel carrying its own, or not needing, an oxidizer. Dönitz was especially fascinated by the work of Dr. Hellmuth Walter, who developed a high-speed submarine powered by the decomposition of highly concentrated hydrogen peroxide. The Walter U-boats would use three different modes of propulsion: diesels on the surface, battery power for most submerged operations, and the Walter turbine to provide bursts of very high speed when attacking convoys. They could outrun most escorts. On June 24, 1942, Dönitz resolved to build a fleet of them; Hitler approved his plans on September 28. But the Walter boats were not a good choice. Apart from the problem that they would not appear in force until 1946, hydrogen peroxide, which could probably not be made in sufficient quantity, was very costly, hard to handle, and dangerous. Postwar British attempts to develop submarines of this sort strongly suggest that the Walter boats were a mistake. Dönitz would have been better advised to concentrate on a less radical closed-cycle system such as diesel engines fed with bottled or liquid oxygen, which conceivably might have been ready in time for the war. A system of this type, when tested, provided better range than the Walter boat.
As the situation in the Atlantic became more desperate, it became apparent that the Germans could not wait for the Walter boats. In March 1943, one of Walter’s engineers, Heinrich Heep, suggested to the director of naval construction that a modified version of the hull designed for the large Type XVIII Walter boat could carry an improved diesel-electric propulsion system that used new diesels, bigger electric motors, and a battery capacity triple that of a conventional submarine. Although not promising as much performance as hydrogen peroxide boats, it would be much faster than current U-boats when submerged. It at least could stay with slow convoys, escape from attacks, and run faster than some of the slower escorts, such as corvettes. It could also be built much sooner than the Walter boats.
Walter himself, at about the same time, suggested using a device the Germans had found years earlier on captured Dutch submarines, the schnorkel (snorkel), which was basically a breathing tube that enabled a submarine at periscope depth to run, albeit slowly and uncomfortably, on diesel power. The Germans incorporated the snorkel in their new designs and added them to conventional U-boats in 1944. The design of the large Type XXI “electro-boat,” as the Germans called it, was finished by June 1943; Dönitz approved the idea, and while work continued on Walter boats, they had lower priority. The new project was such an obviously better alternative that Dönitz, Speer, and others wondered why they had not initiated it a year or more earlier. Being a large craft of about twice the size of the Type VII, however, its manufacture involved a huge effort that seriously taxed German industry. The Germans also planned a much smaller electro-boat, the Type XXIII, for short-range operations in the North Sea and the Mediterranean. Considering its limited armament—only two torpedoes, or as many as the Seehund (Seal) midget submarine carried—it was a poor investment.
In July 1943, shortly after approving the Type XXI’s development and anxious to speed its construction, Dönitz accepted proposals from car manufacturer Otto Merker to build the new types in a radically different way. They would be prefabricated in eight different sections at inland factories. Only the final assembly would take place in conventional shipyards on the coast. The Germans hoped this process would minimize the effects of Allied bombing. The system resembled Kaiser’s construction of Liberty ships and the Germans themselves had built some U-boats this way in World War I, but German naval construction firms rightly suspected that it would not work well with such sophisticated craft. Some U.S. Navy submarines were prefabricated in sections, but this method was applied only to an already standard design by experienced builders such as the Manitowoc Company, which built all the sections in-house and at one site.
The Type XXI and XXIII submarines and the new construction system proved overrated. Apart from the “bugs” to be expected in any new type of equipment, the Type XXI’s diesel engines were less powerful than expected. Their hydraulic systems were vulnerable and unreliable. Further, the sections were often not properly made and were hard to “mate.” The finished U-boats performed far less well than projected. The first ones built were relegated to training. Defects and Allied bombing also delayed the new U-boats considerably; eventually the bombing of the inland water transportation system stopped the sections from reaching the final assembly points. Only a few Type XXIIIs and one Type XXI were ready in time to make war patrols. They seem to have been more effective at escaping Allied antisubmarine measures than at increasing sinkings. While it is difficult to say what would have happened had the new submarines become available years earlier, it seems unlikely that they could have won the war at sea.
Intelligence and Technology
As costly as it was to the Allies in other respects, the U-boat campaign in the Americas did minimize the impact of their losing access to U-boat messages in February 1942. The individualistic nature of U-boat operations in the Western Hemisphere made reading their transmissions much less important for a time. And the British were not quite as badly off for intelligence as they had been before they had started to read the German naval ciphers in May 1941. They had much better photoreconnaissance than before of German ports and observed U-boats being built and readied, and they had a more extensive network of direction finders. Moreover, the Germans’ shift to a separate cipher for communications in the main theater in the Atlantic left the British able to read the ciphers used for U-boats training in the Baltic or based in Norway; and they still read the Home Waters cipher that the surface craft used while escorting U-boats going in and out on war patrols in the Atlantic. So the arrival and departure even of U-boats employing the Triton cipher could be tracked. British estimates of the number of U-boats at sea remained accurate, and they continued to try to plot the positions of individual U-boats at sea. Their main failure was their inability, for some months, to recognize the deployment of the U-tankers, which they mistook at first for a new class of mine-laying submarine.
The Allies, meanwhile, were developing a whole new set of devices and weapons to deal with the U-boats. Early in 1942, they introduced special rescue ships—in effect, small hospital ships specially equipped to pick up survivors—but most Atlantic convoys did not have them. In June 1942, the British began refueling convoy escorts from tankers in the convoys themselves, a process requiring special gear and training for the tanker crews. This ability greatly simplified escort organization and eventually made it easier to spread convoy routes over a larger sea area. The Allies also introduced heavier airborne depth charges, better camouflage for planes, 10cm radars (at first only on surface ships), high-speed direction finders for the escorts, and the Hedgehog ahead-throwing weapon. This spigot mortar fired contact-fused projectiles ahead of an attacking escort. Unlike depth charges, which could only be dropped after passing the U-boat being attacked, these projectiles only went off when they hit something and did not interfere with maintaining sonar contact with the target.
Another successful device was the Leigh Light, a searchlight carried on an aircraft’s wing. While attacking at night, a pilot who spotted a surfaced U-boat on radar used the light to illuminate his target. The Leigh Lights, introduced in June 1942, made offensive patrols over the Bay of Biscay far more effective until the Germans introduced a radar search receiver that could pick up the metric wavelengths that the older airborne radars still used.
Other devices made aircraft more effective against submerged submarines. The sonobuoys (an air-dropped sonar set) and magnetic anomaly detectors (MAD) enabled planes to detect submerged submarines, although the latter was useful only at close ranges. As they overflew their targets, the pilots of the MAD-equipped planes dropped retro-bombs, which were slowed by small rockets, and air-to-surface rockets. When dropped by an aircraft, “Fido”—an especially secret, small acoustic homing torpedo given the misleading designation Mark 24 mine—stood an excellent chance of destroying a submerged submarine.
Return to the Transatlantic Routes
As the convoy system developed in the Western Hemisphere, Dönitz shifted attacks to the main route between Britain and America, although he continued to devote more of the U-boat effort than before to distant operations, mostly in the South Atlantic. The U-tankers and the new long-range Type IXD2 “U-cruiser,” which could reach Cape Town without refueling, made it possible to extend operations to South Africa in September-October 1942 and, later on, into the Indian Ocean.
Some U-boats continued to work near North America and off Newfoundland. There was a bottleneck of sorts, where all convoys going to and from North America had to pass, at least if they were to stay within range of air cover from Newfoundland. Moreover, some small ships did not have enough fuel to let their convoys deviate very far south. In this area, the concentration of Allied ships, the poor visibility from the air, and the fact that planes based on Newfoundland had older and less effective radars made it profitable for Dönitz to keep at least one group of U-boats operating within range of air patrols there and for wolf packs to pursue westbound convoys coming under air cover, something they avoided elsewhere.
In the Atlantic, the Allies continued to be hampered by several factors. (From this point, the escort of the northern Atlantic convoys was almost entirely a British and Canadian job, while the Americans guarded convoys to North Africa.) They were strained to support operations in many areas, while the Canadians were, through no fault of their own, a weak link. The hastily expanded Royal Canadian Navy was at the end of the line for equipment, and its ships had been in continuous action with little chance to rest or refit. Two new types of American aircraft committed to the struggle in 1942, the PV-1 Ventura and PBM Mariner—replacements for the Hudson and Catalina, respectively—proved to be duds or so full of bugs that they were of little value at first. A reduction in the number of convoys and a shortage of tankers forced transatlantic and Sierra Leone convoys to use the most direct routes. And with the success of the German Navy’s B-Dienst at decrypting the British Naval Cypher No. 3, convoys became easier to find. Finally most U-boat operations took place in a big “air gap” in the mid-Atlantic, where convoys did not yet enjoy air cover.
By August 1942, the U-boat fleet had risen to 339 submarines, of which 149 were considered frontline vessels. In late July, convoy ON 113 ran into a wolf pack, lost three of its thirty-three ships, and sank U-90. The Canadian escort had lacked up-to-date radar. ON 115, also with a poorly equipped but skilled Canadian escort group, lost a pair of ships and had another damaged, but it destroyed U-558 and damaged two more U-boats. These battles represented successes for the Allies, particularly considering what the Canadians had to work with, and the Germans could not afford to trade U-boats for merchant ships on anything like that basis. When SC 94 was caught on the Grand Banks heading out for Britain, its escorts again lacked good radar, although two modern British destroyers reinforced the convoy in the middle of a running battle. The convoy lost eleven of thirty-six ships, while the escort sank two U-boats. The Germans, in this case, had reversed their usual tactics, running ahead of the convoy and making successful submerged attacks by day. A wolf pack chewed up SL 118 using the same methods a week later. In late August, ONS 122 with modern escorts, including a group of well-equipped and trained Norwegian corvettes, lost four ships while damaging two out of a pack of nine U-boats.
Against less well-equipped or handled escort groups, however, the Germans scored heavily. Beginning on September 10, ON 127, hitting a submerged day ambush, lost three ships in the first attack plus four more and the Canadian destroyer HMCS Ottawa later. In late September, SC 100 lost four of its twenty-four ships despite bad weather of a sort that usually hampered U-boats. Even with a well-equipped escort, SC 104 lost eight ships from October 12 to October 17, but the escort sank two U-boats. Shortly afterward, HX 212, with a poorly equipped escort group, lost nine ships.
Thereafter, the escort of the North Atlantic convoys was reduced to release ships for the North African invasion. SC 107 and SL 125, running with poor escort groups, suffered particularly heavily. Despite a Canadian plane sinking two U-boats at the start of a weeklong battle between seven escorts (mostly poorly equipped Canadian corvettes) joined by an eighth ship en route and a huge pack of U-boats, SC 107 lost fifteen ships, and the Germans lost three U-boats, all to air attack. This battle led to a belated local reinforcement of escorts near Newfoundland. At about the same time, SL 125 lost eleven ships.
To concentrate the remaining escort resources for Atlantic convoys— for the North African invasion was not a brief, one-shot commitment—the Allies terminated all SL and nonmilitary Gibraltar convoys, inbound and outbound, for six months. Ships headed to Britain from southern waters sailed to North America and joined transatlantic convoys there. This entailed long, roundabout voyages and a further strain on Allied shipping. A fuel shortage toward the end of 1942 also forced opening the convoy cycle from eight to ten days.
The North African invasion seriously handicapped those fighting the Atlantic battle. It diverted escort resources and delayed the deployment of support groups, whose formation had begun in September. The latter were designed not to take individual convoys from one side of the ocean to the other but to serve as mobile reserves and reinforce the escort groups of convoys under threat. Even worse, perhaps, the North African invasion’s requirement for air support tied down the already delayed escort carriers. Most escort carriers had gone to the Pacific (where they mostly ferried planes), and the British were reluctant to use American-built escort carriers in the state in which they were delivered. They regarded them as unstable, requiring the addition of considerable ballast for safety, and thought their aviation fuel systems were dangerous. The last design flaw led to the loss in combat of HMS Avenger with nearly the entire crew in November 1942 and an accidental explosion that destroyed HMS Dasher with heavy losses in March 1943. The modifications the British deemed necessary further delayed the escort carriers’ service. For their part, the Americans complained that the British escort carriers were not commanded by air officers, had inadequate deck crews (a result of the Royal Navy’s shortage of manpower), and lacked onboard repair facilities. In any case, making the changes meant scheduling setbacks.