The mood was grim in Allied capitals on both sides of the Atlantic.
It was early evening on Tuesday, 16 March 1943, in Washington, D.C., and nearing midnight in London. In both cities, senior naval officers were poring over frantic messages coming from the North Atlantic several hundred miles southwest of Iceland. More than 40 German U-boats were launching a mass attack against two eastbound merchant convoys traveling just 100 nautical miles apart.
Slow Convoy SC-122 and Fast Convoy HX-229 had departed New York for the British Isles three days apart, on 5 and 8 March, respectively. A third formation, HX-229A, left port on 9 March. Combined, the three convoys were transporting nearly a million tons of food, fuel, and war supplies to Britain. Stowed in their holds were 170,000 tons of petroleum fuels, 150,000 tons of frozen meat, and 600,000 tons of general cargo, including food, timber, ammunition, disassembled aircraft, locomotives, landing craft, and tanks.
The three formations with 149 merchantmen were not alone on the North Atlantic during the first two weeks in March. The transatlantic maritime pipeline between North America and the United Kingdom was operating at full capacity. Another four eastbound and nine westbound convoys—totaling an additional 653 merchant ships—were at sea.1
Greenland Air Gap: Perilous Passage
Fifteen months since America’s entry into the war, the U.S. Navy and its Canadian and British counterparts had established a convoy system designed to shepherd the maximum number of freighters, oil tankers, and bulk carriers from departure to arrival. Ships that could not steam more than 10 knots were assigned to the slow formations (SC), while vessels that could make between 10 and 15 knots went into the faster convoys (HX).
Leaving port, transports steamed along a 1,000-mile route, protected by vessels of the Western Local Escort Force (WLEF), that led to a designated rendezvous point southeast of St. John’s, Newfoundland. There, they would meet a group of more powerful warships assigned to the Mid-Ocean Escort Force for the 2,300-mile transatlantic passage. Nearing the British Isles, the escort group then would hand the convoy over to a local escort unit for the trip into port. The mid-ocean escort warships then would have anywhere from six to eight days in port for rest and repairs at St. John’s or Belfast, Northern Ireland, before taking the next convoy.
Since convoys at the beginning and end of their runs enjoyed the protection of land-based patrol planes, the U-boats sought them out in the mid-Atlantic, where they were more vulnerable. In March 1943, the Greenland Air Gap—a wide swath of the open ocean southwest of Iceland—was their preferred hunting ground. The 600- to 800-mile stretch of ocean lay outside the maximum range of most Allied patrol planes based in Iceland and Northern Ireland. As a result, convoys and their escort warships were forced to steam without air cover for three to four days before coming under air protection once more.2
U-boat Force commander-in-chief Grand Admiral Karl Dönitz and his U-boat commanders were well aware of this weak spot. In March 1943, most of the 60 U-boats he had operating in the Atlantic were patrolling the Greenland Air Gap. Geography and the limits of Allied aircraft design dictated where the largest convoy battle of World War II would take place.
Each convoy was designed to present as difficult a target as possible for the German U-boats hunting it. The 50 merchantmen in Convoy SC-122 were organized in 14 columns of two to five ships each. With its 37 assigned cargo ships, HX-229 comprised 11 columns of three or four vessels apiece. Every ship would maintain the standard separation of 1,000 yards between vessels in the adjacent columns and 500 yards between the leading and following ships. From the air, each formation resembled a narrow rectangle with the wider sides representing the front and rear rows. The escort warships would take station all around the mass of ships as the convoy proceeded on its course.3
As planned, Convoys SC-122 and HX-229 formed up outside New York Harbor on their departure dates, then set course to the northeast for their assigned meeting points. Nearing the approaches to Halifax, Nova Scotia, a second group of local escort warships relieved the WLEF group and led SC-122 up toward the Western Ocean Meeting Point. While HX-229 made the passage without significant problems, SC-122 ran into a fierce gale that disintegrated its set of columns and rows. Reforming several days later, Commodore Captain Samuel N. White found 11 ships missing, of which eight had aborted because of storm damage.
A much more vexing problem confronted Commodore Maurice J. D. Mayall when his HX-229 arrived at the designated rendezvous: Not a single warship from his escort group was in sight. With his convoy about to enter dangerous waters, something had gone terribly wrong. Mayall had no choice but to continue on course with no escorts.4
The Industrial Race and the Situation at Sea
The struggle between the Allies and Germans at sea mirrored the larger conflict on the ground, in that both sides were mounting a major industrial effort to create the ships, aircraft, technologies, and vital cargoes essential to win the fight. A number of factors at play in March 1943 either would strengthen or weaken the U-boats’ offense or the escort groups’ defense—in this specific moment handing the overwhelming advantage to the U-boats.
Shipbuilding: When the United Kingdom declared war on Germany on 3 September 1939, the U-boat Force consisted of a paltry 57 boats, of which only 22 were fit for North Atlantic duty. “Seldom has any branch of the armed forces of a country gone to war so poorly equipped,” Dönitz later wrote in his memoirs. “It could, in fact, do no more than subject the enemy to a few odd pinpricks.” Adolf Hitler subsequently approved a crash construction program to build a fleet of more than 400 U-boats, but it took three years before the force grew large enough and experienced enough to seriously threaten Allied shipping.5
The U.S. and British navies also struggled. Since 1940, the Royal Navy had been plagued by a shortage of frontline destroyers due to previous combat losses. Beginning the war with 146 destroyers, the Royal Navy by 1941 saw one-half of them lost or seriously damaged. Aggressive repairs had brought the destroyer fleet back up to 170 ships by 1943, but the convoy escort program continually struggled to obtain additional warships as Royal Navy operations expanded elsewhere. Meanwhile, the five British escort groups in the Mid-Ocean Escort Force were suffering widespread damage from the severe North Atlantic storms.
The U.S. Navy had a different problem: It was fighting a two-ocean war. After Pearl Harbor, the Navy was forced to transfer scores of warships—ranging from aircraft carriers and battleships to destroyers and auxiliaries—from the Atlantic Fleet to the Pacific Fleet. By March 1943, only a handful of U.S. Navy ships still were serving on North Atlantic escort duty: Escort Group A3 with two American warships and four Canadian corvettes, and a handful of older destroyers and Coast Guard cutters serving as the “Iceland shuttle” to escort ships to and from passing convoys. One proposed solution was to build a fleet of hundreds of lighter destroyer escorts, but construction delays had plagued the program and only a handful of the 500 planned escorts were in commission in March 1943.6
Aircraft: The lack of sufficient very-long-range (VLR) patrol aircraft created a dangerous weakness in defending North Atlantic convoys. Unlike warships, which could have a difficult time spotting U-boats in the choppy waters of the North Atlantic even when the enemy was hovering at periscope depth, aircraft had a bird’s-eye view that enabled them to quickly spot the shadows of U-boats and relay this information down to the convoy escorts. Airborne radar gave them this ability even when the ocean was shrouded in clouds.
As early as 1942, British engineers had come up with a simple and brilliant solution by reconfiguring the four-engine B-24D Liberator bomber for extended patrol range. Sixty-seven feet long, 18 feet high, with a 110-foot wingspan, the aircraft could carry a 4,500-pound bomb load for 800 miles to its target and return to base. By adding an extra fuel tank in the aircraft’s rear bomb bay and stripping it of armor plating, excess gun turrets, and other unneeded weight, the scientists came up with the VLR Liberator. It had an extended operating range of up to 2,300 nautical miles, enabling it to reach the middle of the Greenland Air Gap from Iceland or Northern Ireland, linger for several hours to seek and hunt any U-boats lurking in the area, and return home after a flight lasting more than 20 hours.
Even though approximately 3,500 B-24s had rolled off the assembly lines by early 1943, Coastal Command had only 18 VLR Liberators in service—12 in Iceland and another six at a base in Northern Ireland. Since one-third of the aircraft were down for repairs or maintenance on any day, this left the Allies with only 12 VLR aircraft. It was just not enough.7
Sensor technology: The Allies by 1943 had developed two key electronic detection systems and a tactical communications system that added a significant advantage to antisubmarine defense. The first was the 10-centimeter (wavelength) radar, installed on both escort warships and long-range patrol aircraft. Not only did this particular radar provide accurate and reliable coverage of U-boats even operating at periscope depth, but the Germans never learned of its existence and failed to develop a radar-warning receiver that would alert U-boats of the radar beams.
The second sensor that strengthened the escorts’ hands was shipboard high-frequency direction finding, a radio receiver that would detect a U-boat’s radio transmission and provide a line of bearing to the enemy. With the gear on board two or three warships around a convoy, “Huff Duff” would give a precise location of any U-boat that emitted a radio signal.8
The third technology developed by the Allies was a tactical radio system called Talk Between Ships, or TBS. Linking all of the convoy escorts with this voice communication enabled far more efficient coordination than older blinking-light Morse code signals or signal flags in the event of a U-boat attack.
Codebreaking: Both the Germans and Allies waged a highly secret “war of the ethers” during World War II. Beginning even before the outbreak of hostilities, the British mounted a major, and highly successful, effort to “break” into the German naval Enigma system used by Dönitz to communicate with his U-boats at sea, and by 1942 they had largely penetrated it. However, in March 1942, a new Enigma machine went into service with a fourth encrypting rotor; for the rest of the year the codebreakers went blind. However, the seizure of cipher materials from a damaged and abandoned U-boat in the Mediterranean before she sank gave the codebreakers entry back into German naval Enigma.
The Germans also were successful. Earlier in the war, the capture of two British merchant ships produced sufficient code materials that German codebreakers were able to read most of the messages sent to and from Allied convoys at sea, including the critical Naval Cypher No. 3, used for critical convoy messages.9
The North Atlantic weather: In the northern latitudes, the Atlantic can shift from tranquility to raging storm in less than a hundred heartbeats, and it is at its deadliest in the long, dark storm season running from September to May. Fierce storms lashed Allied merchant ships and U-boats alike. Beaten by waves and winds, a merchantman might be forced to abort from a convoy and return to port, leaving her vulnerable as a “straggler” to the first U-boat that spotted her. U-boats on patrol in the raging seas frequently found it impossible to locate the enemy, much less mount a successful attack. The waves would violently batter the crewmen in their cramped steel tube, hurling them to the deck or tossing them into the overhead. Each time a wave crashed into the conning tower, tons of seawater would cascade down through the open bridge hatch to drench the watch standers in the control room two levels down. On more than a few occasions, crewmen climbing up to the bridge to relieve the four watch standers found no one there; the ocean had ripped their safety belts and washed them into the sea.
All of these factors would affect the U-boats’ attempt to annihilate Convoys SC-122 and HC-229, and the escorts’ attempt to drive them off. Storm damage to the escorts and the lack of VLR aircraft would tip the advantage to Admiral Dönitz and his U-boats.
Under Strength and Running the Gauntlet
The two escort groups assigned to shepherd Convoys SC-122 and HX-229 were led by veteran Royal Navy officers with extensive convoy service. Assigned to protect SC-122 was Escort Group B-5, led by Commander Richard C. Boyle on board the destroyer HMS Havelock and including two other destroyers—HMS Volunteer and Warwick—as well as five corvettes. The escort group for HX-229 was B-4, led by Commander Edward C. L. Day in the destroyer HMS Highlander. Also assigned to the group were the destroyers HMS Winchelsea and Beverley, as well as six corvettes. That was on paper.
As the two convoys neared their rendezvous for the mid-ocean transit, both escort groups were recovering from a stormy westbound transit. Three days before its rendezvous with SC-122, Escort Group B-5 had finished bringing westbound Convoy ON-168 across from the United Kingdom. However, the escort group would have to begin its next mission without the Volunteer, which was in dry dock for hull repairs. The plan called for her to race and catch up with SC-122 several days later.
Escort Group B-4, on the other hand, was in shambles. The Winchelsea had been detached for refitting, and her replacement—HMS Vimy—had been forced to abort Convoy ONS-169 for Iceland with major storm damage. Day’s own command destroyer, HMS Highlander, was not fit for sea. She too was in dry dock for urgently needed repairs to her Asdic (sonar) dome, without which the warship could not detect submerged U-boats. Of the group’s six corvettes, only four had made the last trip, one of which needed engine repairs, and two of them were still at sea hunting down stragglers from ONS-169 when the 14 March rendezvous with HX-229 occurred.
Described by his colleagues as “sound, blunt, brainy, and very experienced,” Commander Day was nevertheless desperate to avoid sailing his depleted escorts with HX-229 into a slaughter. He requested to Rear Admiral L. W. Murray, the senior Canadian naval officer, that HX-229 shelter in Placentia Bay, Newfoundland, for two days until his escort group could reassemble. Murray said no, citing the disruption that would make to the inexorable flow of successive convoys.
To reinforce B-5, Murray ordered the Volunteer to detach from SC-122’s escort group and sail with Day and B-4 when her repairs were complete. In addition, two short-range destroyers, HMS Witherington and Mansfield, were added to B-4. This was of scant help in the long run, since the two ships had a steaming radius of only 600 miles; they would be forced to leave HX-229 before it even reached the Greenland Air Gap. The old four-stack destroyer USS Upshur (DD-144) was dispatched from Argentia, Newfoundland, to join B-5 as a replacement for the Volunteer.
Worse, the ad hoc roster of ships for B-4 included only one Huff Duff direction-finder. When a U-boat nearby transmitted, the escorts would find it impossible to obtain a cross-bearing fix on the enemy.
An additional nagging problem was that there was no designated rescue ship available for HX-229. These were small oceangoing vessels manned and trained to retrieve survivors from torpedoed merchant ships. In the absence of a rescue ship, the masters of the ships assigned to the end of each column in HX-229 were instructed to take on that dangerous role with no preparation or training.10
There was an even more important problem: B-4 would sail into harm’s way under a temporary commander with limited convoy escort experience and with whom none of the other escort commanders ever had served. The warships lacked what naval experts had learned was the single most important capability in convoy defense: the cohesion of a trained team that could react effectively and quickly to the U-boat threat.
Worse, everyone was aware of what was then happening out in the mid-Atlantic. On 6 March, a force of 39 U-boats in three wolf packs attacked the 119 merchant ships in eastbound Convoys SC-121 and HX-228. Over the next five days, they sank 19 merchantmen and the escort destroyer HMS Harvester for a total loss of 82,549 gross tons. The convoys that B-4 and B-5 would shepherd to Britain would have to run that same gauntlet.
Admiral Murray and his staff on 13 March decided that B-4 would proceed with the ships at hand. Day had no choice but to race after HX-229 in the Highlander as soon as he could and relieve the commander of the Volunteer as escort group commander.
The previous year, in reply to pleas from his subordinates for additional warships, aircraft, and other vital resources, U.S. Chief of Naval Operations Admiral Ernest J. King had issued a message to the service admitting that there was no easy solution, and urging everyone “to do the best with what we have.”
For the two convoys, it was a recipe for disaster.
Wolf Packs’ Feeding Frenzy
Two days after the rag-tag escorts comprising Escort Group B-4 caught up with HX-229 on the evening of 14 March, Admiral Dönitz struck. Although the two convoys had passed their western rendezvous points three days apart, by Tuesday, 16 March, the faster HX-229 had closed with SC-122 to the point that they were only about 100 miles apart. And they were boxed in by three U-boat wolf packs totaling 43 U-boats: Gruppe Raubgraf, with ten U-boats, was in contact with HX-229. Gruppen Stürmer and Dränger, with 18 and 11 U-boats respectively, were east of SC-122 and closing to contact.
At U-boat Force headquarters in Berlin, the daily Kriegstagebüch (Daily War Diary) for 16 March reported that U-653, assigned to the westerly Raubgraf wolf pack, had sighted the convoy and was bringing up ten other U-boats via a homing beacon. In addition, plans were set to have 28 boats from Gruppen Stürmer and Dränger intercept the formation after midnight on 17 March.11
The first victim was the 5,214-ton Norwegian freighter Elin K. When Germany invaded countries in 1940, the BBC invited crews from those occupied nations to come under the protection of the British Merchant Fleet. Master Robert Johannessen and his 39-man crew had chosen a life of self-imposed exile on board their ship rather than submit to Nazi rule. Outfitted with a solitary deck gun manned by six British gunners, the Elin K. since then had made 80 separate voyages around the globe. On this cruise, the ship was bringing 7,000 tons of wheat and manganese ore from Australia to Great Britain. In HX-229, the ship was in Position 101—lead ship in the tenth, or second from the starboard-most column.12
Veterans of the North Atlantic convoy runs had a nickname for that position: the “coffin corner.”
Just before the ship’s clock struck 2000 hours (local) Commodore Mayall in the flagship Abraham Lincoln, 4,000 yards to port at the head of Column 6, ordered a course change for HX-229 from 028 to 053 degrees. At that moment, a torpedo slammed into the Elin K. on her starboard side, ripping open a huge gash in the No. 4 hold. The ship began sinking rapidly, but Johannessen got his entire crew safely into lifeboats without a casualty. They later were rescued by one of the corvettes.
The attack typified the nature of the U-boat war: The Type VIIC U-603 had closed with the starboard corner of the formation, slipped through a gap in the defenses, and fired four torpedoes, aiming for two large ships in Column 1. Three of them missed, but the fourth found the Elin K.
It was the prelude to a slaughter. Escort Group B-4 had only four ships to cover the 45-mile circumference around HX-229, leaving multiple gaps for the U-boats to close within range and launch their torpedoes. Over the next 80 hours, the convoy suddenly would light up as another ship exploded from a U-boat torpedo. While the belated arrival of the Highlander and the corvette HMS Abelia on the afternoon of 18 March helped stiffen the convoy defenses, another three ships would be sunk before the fight ended the next day. In addition to the Elin K., 12 other merchantmen were sunk for an overall loss of 93,481 tons of vital war supplies. While the crews of six ships survived without a casualty, 166 crewmen from seven others perished.13
Convoy SC-122 suffered significant losses as well, beginning with a single U-boat attack on the night of 16–17 March by the Type VIIC U-338. Closing in on the convoy’s port side, U-338 fired two spreads of two torpedoes apiece. All four struck, sinking three ships in the lead row of SC-122 and damaging a fourth later sunk by another U-boat—the four ships totaling 230,735 gross tons. At the end of its own three-day ordeal—somewhat eased by the appearance of several VLR Liberators from Iceland during daylight that drove the U-boats under—SC-122’s total losses were serious, but less than those of HX-229. The convoy lost nine merchantmen for a loss of 51,552 gross tons and 132 crewmen dead.14
‘We Shall Beat the U-boats’
At Derby House in Liverpool, headquarters of the Western Approaches Command, Admiral Sir Max Kennedy Horton saw a rare opportunity in the slaughter of the four convoys. For two years, he and his predecessor, Admiral Sir Percy Noble, had pleaded with Prime Minister Winston Churchill and the Admiralty for additional warships to form “support groups” that quickly could reinforce any convoy escort groups coming under attack. Air Marshal Sir John Slessor, his partner in the Royal Air Force Coastal Command, likewise had pleaded in vain for additional VLR Liberators.15
After the U-boat mauling of Convoys SC-121 and HX-228 ended on 10 March, one of Horton’s senior staff officers came up with an idea to win their long-running argument. Aware that the three wolf packs totaling 43 U-boats were aiming for HX-229 and SC-122, Captain Neville Lake set up an elaborate war game in the command center’s main plot. He added three fictional support groups comprising four destroyers or sloops apiece. Then he dovetailed them with the actual situation taking shape out in the Greenland Air Gap. Using actual weather conditions and maintaining conditions of strict realism, Lake maneuvered the fictional support groups to the aid of HX-229 and SC-122. The results showed that the presence of two support groups would have turned the battle in favor of the escort groups. Summoned to a meeting with Churchill and his aides, Horton took Lake’s wargame report and showed it to the Prime Minister and senior admirals. Horton said, “Give me 15 destroyers and we shall beat the U-boats.” After studying Lake’s document, Churchill assented.16
A similar meeting occurred more than 3,600 miles away in Washington, D.C., where President Franklin D. Roosevelt confronted Admiral King and directed him to provide several dozen B-24s to the British to bulk up their VLR patrol roster.17
Those two decisions borne out of the tragedy of March 1943 would turn the tide in the Battle of the Atlantic. With the Allies’ support groups and additional VLR Liberators on hand, U-boat successes against the convoys steadily dropped throughout April, and in two decisive confrontations in May involving Convoys ONS-5 and SC-130, the beefed-up Allied defenses routed the U-boats, sinking ten while losing 13 ships—a disastrous, nearly one-for-one exchange rate. This led Admiral Dönitz to withdraw them from the northern convoy routes on 23 May 1943. Two years of skirmishing would go on—but the Allies had won Battle of the Atlantic.18
1. “Convoy Web,” convoyweb.org/uk; Ed Offley, Turning the Tide: How a Small Band of Allied Sailors Defeated the U-boats and Won the Battle of the Atlantic (New York: Basic Books, 2011), 13.
2. Clay Blair, Hitler’s U-boat War, vol. 2, The Hunted, 1942–1945 (New York: Random House, 1998), 249–50.
3. Martin Middlebrook, Convoy (New York: William Morrow and Company, 1976), 124.
4. SC-122 and HX-229 “Report of Proceedings.”
5. Karl Dönitz, Memoirs: Ten Years and Twenty Days (Boston: Da Capo Press, 1990), 9–10, 45–47.
6. Clay Blair, Hitler’s U-boat War, vol. 1, The Hunters, 1939–1942 (New York: Random House, 1996), 449–50.
7. Michael Gannon, Black May: The Epic Story of the Allies’ Defeat of the U-boats in May 1943 (New York: Dell Publishing, 1998), 79–80.
8. Blair, Hitler’s U-boat War, vol. 2, 791–92.
9. David Kahn, Seizing the Enigma: The Race to Break the German U-boat Codes, 1939–1943 (New York: Random House, 1991); Jak P. Mallmann Showall, German Naval Codebreakers (Surrey, UK: Ian Allan, 2003).
10. Middlebrook, Convoy, 114–18.
11. “Wolf packs,” uboat.net; U-boat Force KtB, 16 March 1943.
12. Middlebrook, Convoy, 158–61.
13. HX-229 “Record of Proceedings”; “Convoy HX-229,” uboat.net.
14. “SC-122,” uboat.net.
15. RADM W. S. Chalmers, RN (Ret.), Max Horton and the Western Approaches: A Biography of Admiral Sir Max Kennedy Horton (London: Hodder and Stoughton, 1954), 158–60.
16. Middlebrook, Convoy, 289.
17. CAPT John M. Waters Jr., USCG (Ret.), Bloody Winter (Annapolis, MD: Naval Institute Press, 1984), 267.
18. Offley, Turning the Tide, chs. 11–13.
