At 2240 on the 5th, Sunflower was manning station “M” on the port bow when Lt.-Cmdr. Plomer’s radar received a pulse echo from 4,300 yards. Sunflower altered course and closed the contact at 14 knots. The U-boat dived and asdic pursued it. At 200 yards from the contact the bearing began moving from left to right. Following, the corvette dropped six and fired four D/Cs in what Plomer called “our best D/C attack—almost exercise conditions.” Just before the D/Cs went overside, at 2251, Sunflower picked up a second radar contact at 3,400 yards, and Plomer decided to pursue that one at once, in order, we may conjecture, to keep the U-boats off their stride. As he did so, asdic told him that a torpedo was approaching from red (port) 20°. He watched as it passed down the corvette’s port side. Immediately, radar picked up yet another contact at 2,800 yards, but now Plomer decided to pursue the U-boat that had attacked him, and at 2258 he sighted it close ahead.
Sunflowers deck gun opened fire, but on the third round the cartridge jammed in the breach. Without an operative main armament, Plomer altered course to starboard at 2305 in an attempt to drive underwater his radar contact of fourteen minutes before. Two minutes later, asdic reported incoming torpedoes—a “full salvo”—from the boat he had just been pursuing. Putting helm hard-a-port, then point back, Sunflower managed to be 30° off pointing when the salvo arrived down the port side. Plomer signaled Tay at 2312: “Have broken off chase, fired two H.E.s [high explosive rounds], could not gain.” Two minutes later, however, his gun reported clear, and Plomer decided he was back in the game. For the next three and a half hours he chased five contacts, firing Hedgehogs at one and a five-charge D/C pattern at another, but all without result. The NHB/MOD reassessment believes it possible that these attacks were delivered against the same target, U-954 (Kptlt. Odo Loewe).
At 0443, while back on station “N,” 6o° on the convoy’s port bow, Sunflower received a firm asdic contact at 1,200 yards. The U-boat, it turned out, was in the act of surfacing. Plomer closed at 14 knots in 300 yards visibility and found the German fully surfaced broad on the port beam, on a converging course. He switched on his searchlight, and the U-boat immediately commenced a dive. Plomer then ordered hard to port rudder and double emergency full ahead. In the last seconds before impact hard to starboard was ordered as a course correction, and in Plomer’s description, the corvette rammed the U-boat between its conning tower and stern, riding over the U-boat’s casing like an icebreaker over ice. As she passed, Sunflower dropped two D/Cs set to shallow; a moment before they detonated, the corvette’s crew heard another distinct “heavy explosion.”
Plomer was persuaded that the U-boat had broken in two, since his two asdic domes underside were undamaged. His last sight of the U-boat, he said, was of her stern projected about 8 feet above the surface at an angle of 45°. All guns that could bear were brought into action. With no further contact showing on asdic, and convinced that the U-boat had sunk, Plomer set course to rejoin the convoy. Among the spectators of this encounter were the Master and sixty-five other survivors of M.V. Dolius, who had been picked up by Sunflower the day before. Said Captain Cheetham: “I and my crew thoroughly enjoyed ourselves.” While the corvette’s asdic was still fully operative, she soon discovered defects from the ramming, including leakage in the fore-peak. Furthermore, she signaled Tay by R/T: “My steering is erratic as gyro is out of action and magnetic compass shaken up a bit. Please give me a wide berth. 0505.”
In his after-action report Plomer pronounced the engagement a “kill.” Similarly, Captain J. M. Rowland, R.N., Captain (D) Newfoundland, called it a “certainty”. In London the Admiralty was less convinced. Complaining that Plomer’s report contained no details about exterior damage inflicted on the corvette, or about any wreckage, oil, or survivors seen in the water after the ramming, the U-Boat Assessment Committee expressed doubt that the U-boat had been effectively rammed, much less cut in half. It was much more probable, the Committee argued, “that after a glancing blow the U-boat slid off.” And it gave no credence to the suggestion of an internal explosion. As for the two depth charges, it was unlikely that they were in the lethal range. The assessment, given on 21 June, therefore, was: “Probably slightly damaged.”12 But the Committee’s finding may have been disingenuous, for one of its members always consulted Rodger Winn in the OIC Tracking Room for an opinion. While Winn never transmitted raw Enigma to the Committee, or even divulged to it explicit information drawn from Enigma, it is known that both before and on the date of the Committee’s deliberations, Winn held in hand a decrypt of a transmission from U-533 (Oblt.z.S. Helmut Hennig) to BdU, intercepted at 1137 on 6 May and decrypted at 1917 on 9 May:
RAMMED ASTERN BY A DESTROYER [SIC] THAT APPEARED OUT OF THE FOG, LOCATING ME BY SEARCHLIGHT. DEPTH CHARGES. AM MOVING OFF TO REPAIR. BOAT WILL BE READY AGAIN IN 18 HOURS. QU AJ 8683 13
At 1000, U-533 surfaced and made off to the east on course 90° to undertake repairs. These completed by 1800, she continued east, then northeast on 7 May to join sixteen other former Fink boats in forming Group Elbe (after the river). That group and a ten-boat Group Rhein (after the river), organized from former Amsel III and IV boats, were to occupy a 550-mile-long patrol line across the expected courses of two eastbound convoys, HX.237 and SC.129 (see chapter 10). The wounded U-533 successfully took her place in line.14
At daybreak on the 6th, four of the five ships making up the First Escort (Support) Group (EGI), the sloop Pelican and frigates Wear, Jed, and Spey—the slower cutter Sennen was on a different course to support Pink—were closing on ONS.5 from the southwest. In line abreast, four miles apart, their bows cleaving the swells and fog, the warships rode down spur and rein, on 030° at 16 knots, like a seaborne Seventh Cavalry. Numerous R/T signals between busy B7 and EG3 escorts helped the support group home in on the convoy by HF/DF, and at 0550, Wear reported the convoy bearing 330°, 8 miles. The group was now inside the Fink concentration. Senior Officer, in Pelican, was Commander Godfrey N. Brewer, R.N., who, after a year at sea in 1939–1940, had been posted to the Trade Division of the Admiralty as Convoy Planning Officer, where he had the advantage of seeing the “big picture” of convoy warfare. “Escaping back to sea,” as he put it, in spring 1942, he returned to Atlantic escort duty with EGI.
At 0552, Pelican obtained a small radar contact bearing 040°, range 5,300 yards. When it was classified as “submarine,” Brewer closed the contact, keeping it about 10° on the starboard bow to avoid the ship’s “blind spot.” From the bearing and rate of change in the range, it soon became apparent that the U-boat was on a heading reciprocal to that of the group. Brewer thought that it either had just been driven off after attempting an attack or was proceeding ahead to take up a daylight submerged bow ahead attack position. When the range was 3,000 yards at 0557, Pelican began hearing faint hydrophone effect on a bearing of 160°, and several minutes later, when the range had been closed to 500 yards, lookouts sighted a bow wake on the starboard bow.
At 0607, range 300, the U-boat itself became visible on the foggy surface, steering 180°, doing about nine knots, as Brewer judged from the relative speed of approach. It was, he said, “a normal 570 ton type [VIIC] painted a dark colour.” When about 100 yards distant, and fine on the port bow, the U-boat crash-dived, turning to port as she sank. Pelican’s A and B guns and the port Oerlikon opened fire. Brewer swung to port under full rudder and placed his bows just inside the conning tower swirl. As he passed, he fired a ten-pattern set to 50 and 150 feet. After the explosions, a “very weak and hard to hold” echo was regained, and about a minute later, the Officer in Charge and most of the D/C crew sighted at the explosion area what they described as “two thin founts of water, resembling shell splashes.” Brewer came around for a second attack, and during the run-in, with the contact moving very slowly right, hydrophone effect detected various strange noises resembling an Echo Sounder set being switched on and off. This time nine charges set to 150 and 300 feet left the throwers and rails, after which there was no further contact.
A minute and a half later, Pelican heard three “small sharp” explosions together with the same switching noises as before; and nine minutes after that, Pelican heard two more explosions, the second of which shook the ship. None of the explosions, Brewer remarked, sounded like the detonation of a torpedo or a depth charge. Though afterwards Pelican carried out an Observant around the attack position, no wreckage, oil, or survivors were sighted. But based on circumstantial evidence, Brewer’s “considered opinion” was that the U-boat was probably sunk. On 28 June the U-Boat Assessment Committee, basing its conclusion largely on tracking evidence and on the fact that there were no further W/T transmissions from this boat (as Donitz and Godt noticed, too, as early as the end of the day, 6 May), agreed with Brewer’s opinion. So does the recent NHB/MOD reassessment. The victim was U—438 (Heinsohn), which had been damaged by Canso “A” E of 5 Squadron from Gander on the afternoon of the 4th. In good cavalryman fashion, Brewer stated: “This was a good example of a support group arriving at just the right moment to achieve complete surprise.”15
Brewer might have swept about further, seeking other boats to rend and tear, but for the fact that ONS.5 badly needed reinforcement of the close screen, and defending convoys still had the edge over hunting Uboats in escort doctrine. With EGI’s arrival, McCoy on Offa decided that he ought to escort the other remaining EG3 destroyer, Oribi, out of the endangered area as quickly as possible and see her to safety at St. John’s: by daybreak, as a result of her ramming action, Oribi’s forepeak and provision room were both flooded. Accordingly, Offa detached at 0809, ordering Oribi to join and adding a personal message to Ingram: “I should say you have done bloody well during the past 24 hours.” The two destroyers made port at 1215 on 8 May.16
The B7 flotilla left behind was sore beset by battle fatigue and fuel depletion from the night’s running fight; furthermore, with Sunflower licking wounds from her ramming of U-533, Snowflake lacking D/Cs, and Tay with no asdic, Vidette and Loosestrife were the only effective ships on the screen of the main body. So Pelican and Jed took up stations ahead and Brewer detailed Spey and Wear to sweep twenty miles astern. Much later, at 2300, slow-gaited Sennen would join Pink with her four merchant vessels in company.17 On her course toward that rendezvous, which took her to the west of the main body, Sennen acquired two radar contacts, five hours apart, at 0740 and at 1244, which enabled the 1,546-ton ex-U.S.C.G.C. Champlain and her captain, Lt.-Cmdr. F. H. Thornton, R.N.R., to participate in the final moments of the battle. The first contact was obtained bearing 289°, range 4,000, and four minutes later Sennen sighted the U-boat diving at 2,500 yards. When asdic contact was gained three and a half minutes later, Thornton commenced an attack with a ten-pattern set to 150 and 300 feet. Following the attack, which was made at o753½, Sennen regained and lost contact three times, eventually giving up on it and resuming course. Thornton judged that the attack was unsuccessful: “Pattern fired late due to poor recorder trace, and probably too shallow.”18 The NHB/MOD reassessment agrees and identifies the cutter’s contact as U-650 (v. Witzendorff), which had been the shadower in Group Star.19
Sennen ‘s second radar echo at 1244 led to a more persistent effort, as the feisty cutter made no fewer than five separate attacks, two by Hedgehog, and three by D/C, at 1255,1342,1405,1436, and 1522. As in the earlier incident, the U-boat was sighted in the act of diving, this time at 4,000 yards. By asdic recorder Thornton first fired Hedgehog, with no explosions; then attacked with D/Cs set to 150 and 385 feet; then fired Hedgehog, with, again, no explosions; then made two successive D/C attacks, the first of ten set to 150 and 300 feet, the second of five set to 550. With no surface evidence to confirm otherwise, Thornton concluded that the U-boat was “probably not more than badly shaken.” The NHB/MOD reassessment concludes that the U-boat received “minor damage,” and identifies it as U-575 (Heydemann).20 Thornton then proceeded from the area on his original course in order to conserve D/Cs and Hedgehog ammunition, since he had learned that Pink was short of both, and “there were still a large number of submarines in the vicinity.… ”21
While trawling astern of the main body, Spey obtained a radar contact on the port bow, range 5,200 yards, closing rapidly. The time was 0940. Commander L. G. BoysSmith, R.N.R., rang up full speed and altered toward the contact, which was soon classified as “submarine.” At 900 yards the U-boat was sighted in the morning’s thick mist, crossing from starboard to port at an estimated 12 knots. To BoysSmith the boat resembled the large “Dessie” Class Italian submarine. He ordered the frigate’s four-inch to open fire and altered to port, hoping to ram. The U-boat dived at 400 yards, but not before the gun crew got two definite hits, one on the conning tower base and one on the hull, and a third possible. The second hit threw up a heavy shower of debris. Pom-pom and Oerlikon fire also raked the tower as it slid beneath the waves.
Spey quickly established asdic contact and BoysSmith ordered a ten-pattern D/C attack, with lights set to 50 and heavies to 140 feet, carried out by eye over the clearly visible diving swirl and wake; the eyeball order was confirmed by recorder trace. When contact was regained on the port quarter after the attack explosions, Spey set up a Hedgehog attack. Asdic showed that the U-boat had turned at about two knots but contact was lost at 500 yards, indicating that the target had gone very deep by the time the H.H. was fired. There were no explosions. With a contact astern at 700 yards, Spey launched a third attack, employing ten D/Cs set to 500 and 550 feet, after which contact was not regained.
At this point, Wear joined in the sweep, and a less than confident contact was obtained, held to 400 yards. Ten charges set to 150 and 385 feet were delivered by Spey, after which all contact was lost. In Boys-Smith’s opinion, his four attacks were “inconclusive.” The U-Boat Assessment Committee decided: “Probably slightly damaged.” The NHB/MOD reassessment is that U-634 (Oblt.z.S. Eberhard Dahlhaus) suffered damage from four-inch gunfire but none from D/Cs. Dahlhaus’s KTB reveals that he was wounded in the neck by a splinter. His F.T. to BdU reads: a full hit by destroyer artillery after surfacing. port air supply trunk bridge torn away. heavy d/c and radar pursuit. BoysSmith’s target was not a large boat, after all, but a standard VIIC, with 114 more days of life.22
It was after Spey’s attack that the battle’s fever broke. At 1140, having sensed the dimensions of what Germans later would call die Katastrophe am ONS.3, Dönitz and Godt ordered the Fink boats to break off operations. Amsel I and II boats were to head for qu BC 33 (5o°33'N, 39°15'W) and the remainder were to move off to the east, some for replenishment of fuel and supplies from U—461 in AK 8769.23 The order was a recognition that Dönitz and Godt had lost what could have been a drawn battle had they discontinued at dusk on the 5th. In a veiled concession that they had instead reached a night too far, the two German Admirals signaled their Commanders:
THIS CONVOY BATTLE HAS ONCE AGAIN PROVED THAT CONDITIONS ON A CONVOY ARE ALWAYS MOST FAVORABLE AT THE BEGINNING. HE WHO EXPLOITS THE MOMENT OF SURPRISE ON THE FIRST NIGHT, AND PRESSES HOME THE ATTACK BY ALL MEANS IN HIS POWER, HE IS THE MAN WHO IS SUCCESSFUL. AFTER THE FIRST BLOW IT BECOMES HARDER AND HARDER. IN ADDITION THERE IS THE UNCERTAINTY OF THE WEATHER, AS ON THIS OCCASION, WHERE THE FOG RUINED THE GREAT OPPORTUNITIES ON THE SECOND NIGHT. WE APPRECIATE YOUR HARD STRUGGLE, ESPECIALLY ON THE SECOND NIGHT.24
In their wash-up on “Convoy No. 36” at the close of 6 May, Dönitz and Godt concluded that six boats had been lost in the Fink campaign—U-638, U-192, U-123, U-331, U-630, and U-438. “If none of these boats report later, this loss of 6 boats is very high and grave considering the short duration of the attack. The blame can be laid mainly on the foggy period that began at 2100 [GST] on the 5th May.” If the fog had held off for six hours, they contended, the U-boats would have had “a really good bag that night,” but “the fog ruined everything.” They did not concede that staff meteorologists, from a year and a half of U-boat experience in the western Atlantic, not to mention book knowledge, should have known that where the Gulf Stream met
the Labrador Current, causing warm water to mix with cold air, there was almost always opaque vapor, especially in the spring, and that the Grand Banks were renowned for their milk-white air. Nor did they concede that the same fog that blinded the U-boats made air cover from Newfoundland impossible for the enemy. Curiously, the Naval Staff at Eberswalde, not many kilometers from BdU, did anticipate the whiteout: “As the enemy is today entering the heavily fog-bound area, it is to be expected that only a small portion of the boats will be able to maintain contact.” This was on the 5th. Whether there was communication with BdU on the point is not disclosed in the extant records.25
The U-boat loss count would be even higher, by one, on 23 May, when BdU acknowledged that U-209, damaged by Canso “A” W 5 Squadron on 5 May, had foundered with all hands (probably on 7 May in the vicinity of 52°N, 38°W) during her desperate attempt to make base26 And one could add as well the loss of U-710, sunk by Fortress “D” 206 Squadron on 24 April during the first stage of the battle. The exchange rate of U-boats lost for merchant ships sunk in the two stages was alarmingly high, even given the inflated figures of ships sunk that were transmitted by Commanders to Berlin. The actual number of merchantmen lost to U-boats from ONS.5, beginning with McKeesport and ending with Bonde, was thirteen. The number reported to Berlin was nineteen merchantmen torpedoed and sixteen sunk (90,500 GRT), including Hasenschar’s erroneous count of two definites, including a corvette, plus two probables, which led Donitz and Godt to add to their “hard struggle” message, cited above: hasenschar is champion shot.27 That honor should have gone to Jessen (U—266), with three definites.
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