The Battle of the St. Lawrence

by Nathan M. Greenfield

  “On the day we’d been told to expect something [September 26],” recalls Piers, “about 9 p.m., I got a call telling me that the radar had picked up the submarine. I decided to wait before calling the ships into action. Then I got another call, this one from the shore patrol. The message—‘We have a guy here making his holiday. He’s pretty mad. He says you are ruining his holi day. Should I let him go?’—was code. I immediately knew we had our man and replied, ‘No, don’t. Take the fellow and bring him up here. If he tries to get away, shoot him in the legs. Whatever you do, don’t let him escape.’

  “Twenty minutes later or so, they brought him up. I wasn’t in uniform, so he did not know I was a naval officer. He began to harangue me about interfering with his holidays. He tried to make a strong case for himself. I asked if I could look in his briefcase. He produced a few papers that were in German. One of his papers was from Northern Electric. It thanked him for the work he’d done for the Battle of the Atlantic.”

  Piers then asked him, “What do you do for money?” The prisoner’s wallet was full of ten-dollar bills, hundreds of dollars worth. “The only thing,” recalls Piers, “was that they were all from 1911, honouring the coronation of George V. I knew they’d gone out of circulation years ago.”

  Piers reached into Heyda’s briefcase and pulled out a circular typewriter-ribbon box. “I opened it and found in it a compass. ‘That’s what I use for orienteering,’ he said.”

  Next Piers pulled out a small object wrapped in paper. He unwrapped it and found German chocolate issued by the Red Cross.

  Finally, Piers pulled out a letter, apparently signed by Chief of Naval Staff Percy Nelles. “His other documents were rather finely done. His ID card, especially, looked just like a real one, even though it had been forged by hand. Nelles’s signature was, however, nothing like the real one, which I knew quite well. After looking at it for a moment, I looked straight at him and said, ‘I am Lieutenant Desmond Piers of the Royal Canadian Navy and you are Wolfgang Heyda, an escaped POW, and I will have to turn you over to the RCMP.’”

  Just as Heyda was finishing giving his name, rank and serial number, Piers’s radar operator called out, “Sir, we’ve got a contact.” Piers alerted Rimouski to close in.

  Had Schauenburg’s Metox been working, he would have known he’d been picked up by Piers’s radar, but since late on September 26, he had already suspected that the Canadians were waiting for him. According to his second lieutenant, just before leaving the Baie des Chaleurs on the twenty-sixth (so that he could surface and recharge his batteries), Schauenburg spotted Piers’s task force. Instead of moving out of the bay, he stayed submerged, watching the disposition of the ships. At one point he saw “the corvette, lying off the point [where the pickup was to occur], move off” and be replaced by another, a manoeuvre that, in the words of the Allied intelligence officer who interviewed Schauenburg, made it “abundantly clear to him that the German plans were known.”

  Later, Schauenburg’s suspicions were confirmed. Despite a dazzling display of the northern lights, he saw a light flashing “Komm Komm” (“Come closer, come closer”) in plain Morse code instead of the pre-arranged signal. Scant moments later, “distant explosions of depth charges” were “heard.” Taken on their own, they could have been “exercise bombs,” but taken with the deployment of ships and the unexpected signal, Schauenburg recorded the explosions as either “scare bombs,” designed to make him move and show himself, or real depth charges fired at a false target.

  Schauenburg’s assumption was wrong. The depth charges were real enough, but were not fired off as part of a carefully co-ordinated attack but, rather, as a defensive measure. “We cruised in,” recalls Pickford, “feeling naked indeed. We had no defence against the Gnat torpedo. The tactics were to drop a depth charge from time to time “to distract the acoustic homing torpedo.”13

  Piers’s radar bearings gave Pickford a general idea of where to attack, but, as had so often been the case in the Battle of the St. Lawrence, the RCN’s plans were undone by the bathyscaphe effect. “The asdic conditions in the shallow Baie des Chaleurs were just hopeless,” Pickford recalls. “We got no contact.”

  Schauenburg’s next manoeuvre compounded the RCN’s problems. Instead of making a run for it, he decided that the only way to save his ship was to do exactly what the attacking ships would never expect: to head for shallower waters, where the U-boat would be in greater danger if it were depth-charged but so would the attacking ships.

  The ploy worked. Rimouski and its consorts and Piers’s radar spent the rest of the day and the night searching the waters off Maisonette Point. “They couldn’t find a bloody thing,” recalls Piers. “The next morning, there was the sun sparkling on the water and nothing in sight, as if nothing had happened there.”

  Forty metres below the dappled water, however, the situation aboard U-536 was rapidly deteriorating. They’d been underwater for almost two full days. “We had no fresh air in the boat, and the crew needed to get out because without air we would start feeling sleepy and die.”

  With the Canadian ships still trawling for him, and with just a few metres of water above his conning tower and as little below his keel, Schauenburg used his silent electric motors to ease U-536 out of the Baie des Chaleurs. One officer recalled the nerve-racking experience during his interrogation: “We could hear with our own ears the propellers of the ships going over our boat, and we guessed that in the coming seconds depth charges would explode and sink or damage us, but nothing happened …. We said to each other, ‘Our last hour has come.’”

  But the gambit worked, though not before U-536 got caught in a fishing net. The fishing trawler was so close that Schauenburg’s crew heard the sound of the boat’s winches pulling in the net. Not until October 5, when he was within 180 miles of Cape St. Mary’s, Newfoundland, did Schauenburg radio Lorient, “Kiebitz verpfiffen”: “Operation Magpie blown.”

  Six weeks later, on November 20, east of the Azores, U-536 became the only submarine that invaded the St. Lawrence to be sunk by a largely Canadian force. As Hadley writes,

  The attack [by the corvettes HMCS Snowberry and Calgary and the frigate HMS Nene] was in fact devastating. The U-boat suddenly became stern heavy while lights failed, the fuse box burst into flames, and yellow smoke billowed. In short order, U-536 was thrust perilously into the perpendicular, balancing on its screws, and hurtling to a depth of 240m. Despite the violence of the movement, the resourceful chief engineer, Wilhelm Kujas, managed to stabilize the hopelessly damaged boat which he himself would not escape. As the U-boat rose to the surface and chlorine gas formed in the bilges [because of acid mixing with salt water], the crew gathered in the control room to abandon ship.

  Most of the seventeen men who survived the depth-charging and the subsequent machine-gunning of those who made for U-536’s deck gun were picked up by Snowberry. A story published on February i, 1944, quoted Snowberry’s captain, Lieutenant J. A. Dunn, RCNVR, telling the Canadian people—who by then had endured four years of war, the disaster of Dieppe, the loss of nine warships including Raccoon and Charlottetown to enemy fire and the sinking of nineteen ships in Canada’s inland waters, and who were now daily reading of their troops fighting in Italy—something they desperately wanted to hear: “There was no evidence to make us believe that these [men] were members of a ‘Master Race.’ They were a very docile and thankful collection of survivors.”

  CHAPTER EIGHT

  1944

  OCTOBER 14 AND NOVEMBER 24, 1944

  HMCS Magog and Shawinigan

  They that go down to the sea in ships; and occupy their business in great waters; These men see the works of the Lord; and his wonders in the deep.

  —BOOK OF COMMON PRAYER

  On June 6, 1944, against almost 7,000 vessels (including 110 Canadian destroyers, frigates, corvettes and minesweepers) standing off the Normandy coast, the once powerful U-Bootwaffe could muster only 36 operational U-boats.1 Over the course of D-Day, as the A
llies disgorged more than 130,000 troops along a fifty-mile strip, famously divided into Gold, Sword, Juno, Utah and Omaha beaches, Dönitz’s men sank a single ship, the Norwegian destroyer Svenner. Allied ships and planes sank nine U-boats before BdU ordered back to their bases the remnants of the fleet that had once terrorized the Atlantic and sailed as far up the St. Lawrence as Rimouski.

  In the year since Black May, when 41 U-boats were sunk and another 37 badly damaged—numbers that prompted Dönitz to withdraw U-boats from the North Atlantic and to confide to his diary, “We have lost the Battle of the Atlantic”—thousands of Allied ships and planes had relentlessly pursued the U-boats. Deployed according to ever-more-accurate intelligence (Ultra decrypts were in Admiral Murray’s hands in Halifax almost as fast as U-boat commanders had the original signals in theirs), Allied ships and planes with more accurate radar and sonar and more deadly munitions sank 286 U-boats. Allied shipping losses dropped from almost 525,000 tons in March 1942 to just under 165,000 tons in May 1943. A month later they had fallen to 18,000 tons. The average monthly losses in the six months leading up to D-Day were some 30,000 tons; in the month before D-Day, U-boats destroyed only 15,000 tons of shipping, the second-lowest monthly total since the war began.

  Though overshadowed by the USN and the RN, which between May 1943 and D-Day sank fifty-six and eighty-five U-boats respectively, the RCN acquitted itself well. Between May 13, 1943, when HMCS Drumheller received partial credit for sinking U-753, and April 22, 1944, when HMCS Matane and Swansea combined to sink U-311, fourteen RCN ships had taken part in sinking another nine U-boats. By the end of 1944, another eleven RCN ships would sink eight more U-boats. On July 7, 1944, an attack group composed of HMS Statice and HMCS Ottawa II and Kootenay sank U-678. On August 18, 1944, an entirely Canadian attack group, EG-11 (HMCS Ottawa II, Chaudiere and Kootenay), sank U-621; it was U-984’s turn two days later. Thus did the RCN demonstrate that it had overcome the manning and training difficulties that had caused its withdrawal from the North Atlantic in 1943.

  But even as the Freikorps Dönitz lost thousands of men between May 1943 and October 1944, the U-boat force fought on. From the beginning of the war, der Löwe (the Lion), as his men called Dönitz, assiduously cultivated the U-Bootwaffe’s esprit de corps—by greeting returning boats at the dock, by arranging for special trains to transport crews on liberty to spas and other rest areas, by making allowances for misbehaviour on shore, by personally lending money, by ensuring that U-boat crews had special food and chocolate. He even allowed personal messages to be broadcast from Lorient, the most famous being the news to one expectant father that “a U-boat with a periscope arrived today. “2

  Morale held among the “grey wolves” despite devastating losses. During the first four months of 1944, 80 per cent of U-boats that put to sea were sunk. Still, Werner Hirschmann, chief engineer of U-190, recalls, “We were young and sure of ourselves; it was always the ‘other guy’ who wasn’t going to make it back.” Kapitänleutnant Helmut Schmoekel, commander of U-802, recalled in an interview, “We left Kiel in January 1944. I was so optimistic that I told my fiancée that when I get back in May we will be married.”

  As both Herbert Werner (U-415) and Peter Cremer (U-333) make clear in their memoirs, one of the reasons morale held was the U-Bootwaffe’s faith that Dönitz’s long-delayed promise of new technologies would be fulfilled. In the middle of Black May, historian Peter Padfield notes in his biography of Dönitz, the Grossadmiral signalled all boats:

  In his efforts to rob U-boats of their most valuable characteristic, invisibility, the enemy is some lengths ahead of us with his radar location.

  I am fully aware of the difficult position in which this puts you in the fight with enemy escorts. Be assured that I have done and shall continue to do everything in my power as C-in-C [commander-in-chief of the German navy] to take all possible steps to change this situation as soon as possible.

  Research and development departments within and without the navy are working to improve your weapons and apparatus.

  Four days later, in the signal that told that he was abandoning the North Atlantic, Dönitz again promised “new and sharper weapons” with which “you will be superior and will be able to triumph over your worst adversaries, the aircraft and destroyer.”

  The magic technologies—hulls covered with radar-and sonar-absorbing materials, the “Elektro boat” (a larger U-boat with huge electric motors that gave it an underwater speed of 17 knots, some 11 knots faster than either Type VII or Type X) and the “Walter boat” (which burned hydrogen peroxide, obviating the need for air for its engines)—either never arrived or arrived too late to affect the outcome of the war.3 Two combat-design Walter boats were produced. On a shakedown cruise that began on November 15, 1944, U-2519, under the command of “Ali” Cremer, reached 17.5 knots underwater. On April 5, 1945, while it was in dock at Blohm & Voss in Hamburg, Allied bombers destroyed Cremer’s boat. Walter boats undertook no operational cruises.

  However, two technologies did arrive early enough to be deployed in the Battle of the St. Lawrence: the acoustic torpedo and the Schnorchel. The T-5 Zaunkoning acoustic torpedoes, nicknamed “Gnat” (for German navy acoustic torpedo) by the Allies, came into service in August 1943. Billed as “destroyer crackers,” Gnats were equipped with acoustic sensors tuned to 24.5 kHz and attached to the torpedo’s guidance mechanism. Instead of the mechanism executing a programmed course, it directed the torpedo toward the sound created by the target’s propellers. Countermeasures such as altering a ship’s speed, dropping depth charges (the explosion of which caused the Gnat’s firing pistol to go off prematurely) and steaming noisemakers that attracted the torpedo away from the ship were routinely used by Allied ships after the middle of 1943 when U-boats were known to be near.

  The Schnorchel, developed by the Royal Netherlands Navy in 1933, was a simple device that turned the U-boat from a submersible weapons platform into something approaching a true submarine. Prior to the introduction of the snorkel in 1944, U-boats spent on average only 10 per cent of their running time underwater because of limited air supply and battery power. The necessity of surfacing to recharge the ship’s batteries and air supply meant that the Bay of Biscay, which was heavily patrolled by Allied ships and planes, became less a passageway to the Atlantic than a killing field. In 1943, twenty-seven U-boats were destroyed there; in 1944, another twenty-six were sunk.

  A set of physically ungainly tubes attached to the conning tower, the Schnorchel was elegant in its simplicity. Each of the two 25-foot tubes extended no more than a foot above the surface of the water, making it invisible to lookouts and to all but the best Allied radar. One tube drew fresh air into the boat; the other served as an exhaust. Each was fitted with a valve (the most common was a ball-type float connected to a flap) that shut when water washed over the tubes. To keep the diesels running when waves washed over the Schnorchel, the float valve triggered another valve that allowed the combustion engine to suck air from the U-boat and to vent the diesel exhaust into it. Though fouling the boat’s air was, of course, a concern, the immediate effect of this procedure was first a rapid decrease in air pressure and then an increase, which caused intense ear pain. Although Dönitz’s engineers had originally thought that the snorkel would be used only for recharging a boat’s batteries, tests revealed that U-boats could operate using a snorkel for long periods of time at speeds up to 13 knots.

  Six weeks after D-Day, on July 17, 1944, as thousands of British and Canadian troops readied for the following day’s attempt to break out of Caen, some 15 kilometres from the Normandy coast, Dönitz again ordered U-boats into the St. Lawrence, in hopes of drawing Allied escorts off the North Atlantic. Over the next four months, four radio operators would hand their captains the following message from the Führer der Unterseeboote:

  [This] operational area has not been occupied since 1942. Great surprise successes are possible as area has abundant traffic. Area was evacuated in view of appearance of a/c [a
ircraft] and location [anti-submarine radar], which impeded battery charge. But area is easily navigable with “Schnorchel.” …

  4. Countermeasures: Situation in 1942

  Medium to strong air with and without location [radar], especially after being observed. Sea [naval] countermeasures relatively slight and unpractised. Location [sonar] conditions very unfavourable to the enemy, as there is marked underwater density layering. Find out about this density layering, even for considerable depths, before a depth-charge hunt starts.

  In General: Main defence by a/c. Sea defence little to be feared. Situation thought to have altered little since 1942.4

  Between the beginning of July 1944 and the end of November 1944, U-802, U-541, U-1223, U-1228 and U-1231 invaded Canadian waters. Despite Kapitänleutnant Helmut Schmoeckel’s claim that U-802 had sunk a “destroyer” on September 13 (the torpedo he fired at HMCS Stettler exploded prematurely), he had nothing to show for his patrol in Canadian waters. There were, however, frightening memories of being attacked by both the RCAF and USS Bogue‘s hunter-killer group. RCAF coverage so unnerved Schmoeckel that he credited Canadian land-based radar with being “able to pick up my Schnorchel,” an ability it did not have.

  Kapitänleutnant Kurt Peterson’s bravado on U-541 led him to claim that the layering effect of the salt and fresh water in the gulf made him feel “as secure as in the bosom of Abraham.”5 His one attack in the gulf, however, was carried out on the surface. The attack was broken up by gunfire from the corvette HMCS Norsyd. Upon leaving Canadian waters, Peterson’s war diary recorded the cost of having broken radio silence: “About two hours [after having broadcast] we heard weak signals on our radar warning devices …. Seconds after we had dived, bombs exploded in our vicinity. The boat was shaken and the periscope developed a leak. From my perspective the Canadian defences had reacted and operated magnificently. Swift detection of our radio transmission, good evaluation with precise position, good attack by aircraft with sparing and rational use of radar. If we had dived but a few seconds later, the bombs would possibly have hit us at the beginning of the diving manoeuvre.”