Black May (52 page)

By daybreak on the 12th, a considerable number of boats were trying to work their way around to the front, with U
-186
(Kptlt. Siegfried Hesemann) acting as shadower. Dönitz/Godt urged them onward:
DO NOT SLIDE BACK. FORWARD WITH THE HIGHEST SPEED.
³⁹
At 1133
Hesperus
obtained an HF/DF contact bearing 020°, ahead of the convoy about 15 miles, and shaped course to investigate. At 1205, with speed reduced to 20 knots to allow for an asdic sweep, Macintyre received a strong echo classified “submarine.” Two minutes later, he made a Hedgehog attack, but there were no explosions. Then, 30 seconds later,
the U-boat showed its periscope at 50 yards Green 10°, crossing from starboard to port. Macintyre pursued and fired a ten-pattern, followed by a second H.H. salvo at 1219, again without result. Asdic contact was then lost, leading Macintyre to assume that the boat had gone deep. By hydrophone effect, however, he regained the target, at 1215½, and made a deep drop of ten Minol and Amatol D/Cs set to 350 and 500 feet. Eighteen minutes later, just before a planned deeper drop,
Hesperus
heard a series of explosions. A fourth and last attack with ten D/Cs set to 550 and 700 feet was carried out at 1233½. Then, at 1245, a single “sharp” explosion—probably internal—and “peculiar noises” were heard quite near the destroyer; soon afterwards, wreckage and oil came to the surface. The victim was the shadower U-
186,
on her second combat patrol.
⁴⁰

During the rest of the afternoon there was heavy HF/DF activity. Between 1530 and 1930 the close escort made six sightings and two attacks. At dusk, the convoy acutely altered course 40° to port on to 343° in order to “throw the U-boats out of position.” A large-scale night attack by the
Elbe I
and
II
boats—there were twenty-two remaining after one sunk and two forced back to base with damage—was feared by Macintyre, but to his surprise it did not materialize; one lone attack was turned back by
Hesperus
and the corvette H.M.S.
Clematis.
By the morning of the 13th, HF/DF traffic had greatly diminished, and the appearance overhead later in the day of VLR Liberators no doubt added encouragement to EG B2's aggressive ahead-of-convoy patrolling. When BdU received a signal from the
Elbe
boat
U-642
that it had sighted a carrier
(Biter)
proceeding on a southwest course at high speed, obviously to lend succor to SC.129, BdU concluded, the decision was made in Berlin to call off operations against the convoy on the 14th.
Biter
joined SC.129 at 1400 on that day, when, because of its threat alone, the U-boats had already been ordered away. Two days later, absent any further contact with the enemy,
Biter
and EG5 disengaged, and four days later still, the convoy arrived safely in home waters.

While “powerful air escort” was named the principal reason for ordering withdrawal, BdU was equally concerned that during the 12th
when twelve boats were in contact with the convoy and
no
air escort was yet available, the U-boats still failed to achieve results. It could only surmise that with some unknown shipborne detection devices (actually HF/DF and centimetric radar, primarily the former), “the enemy must have picked up all the boats around the convoy with astonishing accuracy.” It observed that “such a rapid detection of the boats has not previously occurred on such a scale.”
⁴¹
The campaign against HX.237 and SC.129 had sputtered and failed despite excellent intelligence about the convoys’ positions, courses, and alterations, and despite the fact that altogether, about thirty-six U-boats operated against the two convoys.

The plain fact was that the U-boats’ 1939-period technology (excepting certain torpedo advances) was now no match for the 1943-period sophisticated detection equipment, target plotting tactics, and state-of-the-art weaponry of the surface escorts, not to mention the operational research-developed tactics of the air escorts and their new Mark XXIV Mine. Herbert Werner, I.W.O on U-230, complained to the writer that the “May disaster” was owed to the “unconscionable policies of the U-boat Command” that required crews to go to sea that late in the war with “obsolete and inadequate equipment, weapons, and tactics.” The BdU staff, he asserted, “had not prepared for this disaster. It discounted what the Commanders were reporting from the field. It didn’t want to face reality—the inevitable that was to come.”
⁴²

While that view may be regarded as extreme by other U-boat veterans of Black May, it is beyond serious dispute that by that month, if not earlier, the U-boat, considered as a high seas detection instrument and weapons platform, was outclassed by the
quality
of the Allied forces, sea and air (excluding the Swordfish), arrayed against it. The
numbers
still favored the U-boats, but the disparity in quality was starkly apparent. Add to that the ever-widening gap between the experience and proficiency levels of the human components on either side, and the reasons for what Werner called “the May disaster” were all the more manifest. The material inequalities were reflected in BdU’s bar graphs. Since the pivotal Battle for ONS.5, the exchange rate of U-boats lost for merchant ships sunk suffered an ineluctable, if uneven, decline: In the battle for HX.237 the U-boats had exchanged three
U-boats lost for four stragglers sunk; and in the battle for SC.129 they exchanged one boat sunk and two severely damaged for two convoy vessels sunk. In Convoy ONS.7 to follow, the loss ratio would be one-to-one, and, strikingly, that one merchant ship lost to enemy action would be the last lost in the Northern transatlantic convoy lanes for the remainder of May and the whole of June.

On 11 and 12 May BdU collected twenty-five U-boats from those just entering the North Atlantic from French, German, and Norwegian bases, as well as from those that were refueling in midocean from the supply boats U-459, U—U-119, U
-461,
and U
-514,
and formed them into five small groups, placed southeast of Greenland, named picturesquely after rivers:
Lech, Isar, Inn, Illier,
and
Nab.
Westbound Convoy ONS.7, having departed the U.K. on 7 May under the guard of EG B5, encountered
Iller
on the 13th when U
-640
(Oblt.z.S. Karl-Heinz Nagel) reported sighting its columns in AL 1265. Later on the same day, Groups
Inn
and
Isar
were ordered to combine forces in a new patrol line, Group
Donau
[Danube River]
I,
and
Lech
and
Nab
were similarly joined to form
Donau II,
both new groups charged with the task of interdicting U-640's convoy. The
Iller
group, of which U—6
40
was a part, was ordered to operate independently against ONS.7.

But shadower U
-640
herself would not be a factor for long, since, early on the next day, she was caught on the surface at position 6
O
°32’
N, 3I°O5
‘W by Catalina “K” of USN 84 Sqdn. based in Iceland. In 7/10th cloud with bases at 1,700 feet and visibility ten miles, K/84 sighted U-640 sixteen miles from the convoy and, at 0739, initiated an attack from the still-surfaced U-boat’s port beam. At 75 feet off the deck the pilot released three USN 350-pound depth bombs (D/Bs) set to shallow 25-foot depth. Nos. 2 and 3 D/Bs straddled the boat, and following their explosions, the “blue-black” hull slowed from 8 to 2 knots, left a path of air bubbles 20 yards wide, became stationary, wallowed, listed at a sharp angle, and sank.
⁴³

There were no further incidents during ONS.7’s passage until shortly after midnight on the 17th, when
Iller
boat U-657 (Kptlt. Heinrich Göllnitz), on her first combat patrol (out of Norway), put two
torpedoes, two minutes apart, into the 5,196-GRT British steamer
Aymeric,
which had the unhappy distinction of being the last northern transatlantic ship under the red duster to go down in May or in the whole of the month that followed. The ship’s foremast collapsed; the hatches from No. 1 hold, the rafts from the fore rigging, and even the derricks were blown over the side; while slag ballast was strewn everywhere. Moments after the second torpedo, the ship’s boilers exploded, fracturing both port and starboard sides of the vessel. A number of the Lascar crew panicked while lowering the boats and lives were lost as a result. The ship went under five minutes after the first explosion. Men found themselves swimming in bitterly cold water, where many became stiff and sank. The survivors were rescued by a rescue ship and a trawler. Of the seventy-eight-man crew, fifty-three died. It was one of the worst human tolls of the month.
⁴⁴
But the drowned and frozen would not go unavenged.

H.M.S.
Swale,
SO of EG B5, ordered “Artichoke” and swept out herself 6,000 yards astern of the victim’s position. There, at 0138, she obtained an asdic contact classified as “submarine,” bearing 285°, range 900 yards. Three minutes later,
Swale
was on top of the contact with ten D/Cs. When no evidence surfaced, she fired Hedgehogs at 0203. There were no explosions, but the bridge observed patches of light oil in which, peculiarly, small yellow flames appeared. The River-class frigate then fired a second H.H. salvo at 0224 and, 33 seconds later, heard a single loud explosion followed after 107 seconds more by two “muffled” explosions. At 0231, just to be sure,
Swale
dropped a ten-pattern set to 150 and 350 feet over the position, and was rewarded by two loud explosions five and a half minutes later and a second appearance of oil patches.
Aymeric
s slayer would not surface again. The position where forty-four young Germans paid the stern price was 58°54'N, 42°33'W.
⁴⁵
Convoy ONS.7 continued its passage without further hindrance, joined briefly from daylight on the 18th to 1100 on the 19th by the four-destroyer Third Escort (Support) Group. Close escort B5 was relieved by the Western Local Escort Group at WESTOMP on the 21st and the convoy entered Halifax four days later.

As long before as February, reckoning on the eight-day cycle for departures of ONS and SC convoys, Commander Peter Gretton, SO, Escort Group
B7,
had set a date at the end of May when he pledged he would be in London to meet a Wren whom he had courted at Gilbert Roberts’s Tactical Unit (WATU), and there exchange vows of matrimony with her in St. Mary’s, Cadogan Square. At 1330 on the 14th of the month, his prenuptial voyage began, as a now-familiar company of warships—
Duncan, Vidette, Tay, Loosestrife, Snowflake
(her mate, the injured
Sunflower,
to follow), and
Pink
—slipped their moorings at St. John’s, Newfoundland, and bore eastward through the inevitable fog. Joining the escort at sea were the rescue trawler
Northern Spray,
also of ONS.5 fame, and an extra corvette, H.M.C.S.
Kitchener.
At 0600 on the 15th, still in fog,
B7
met the convoy entrusted to its care, SC.130, consisting of thirty-nine merchant vessels, not including a rescue ship,
Zamalek.

Heavily laden with grain, sugar, pulp, lumber, fuel oil, gas, and general cargo, the merchant fleet, with many old coal burners, was not expected to exceed seven and a half knots, but Gretton was confident that,
pace
adverse seas and unkindly U-boats, the convoy would reach the U.K. by its due date, the 25th. The first night of passage was spent in thick fog, and when a large iceberg was encountered,
Vidette
positioned herself, fully illuminated and whistle blowing, between it and the advancing columns. That danger past, the rest of the night was spent making steady revolutions on course 081°. With daybreak on the 16th the veil of fog lifted and the columns moved smartly ahead at eight knots.
Sunflower
joined at 1100. Good clear sailing weather continued on the 17th, and five RCAF Fortresses patrolled the surrounding water, though Gretton complained: “The air escort from Newfoundland are not yet trained to convoy work. Their communications are bad and they do not fully understand homing procedure.”
⁴⁶
He particularly regretted that the only day SC.130 was without air cover was the next day, the 18th, when the convoy was sighted by the enemy.

At 2219, in 54°39'N, 36°47'W, rescue ship
Zamalek,
which was equipped with FH3 HF/DF, reported a ground-wave signal to the north. Beginning at 0116 on the 19th the air filled with HF/DF
contacts—
Duncan
was fitted with FH4 and
Tay
with FH3—and cross-cuts revealed the presence of four U-boats, one close on each bow of the convoy and one on each quarter. Taking the role of hunter,
Duncan
went after the boat judged to be four miles on the port bow. A radar contact was obtained at 5,000 yards, but the boat dived before being seen on the bright, full-moonlit sea.
Duncan
fired a five-charge pattern in the estimated diving position and started operation “Observant.”
⁴⁷
Though without visible result, this first attack, which kept a U-boat down and out of the game, was representative of the aggressive behavior the B7 escorts displayed thereafter over the next forty-eight hours against an enemy force numbering altogether thirty-three U-boats, though apparently no more than twenty would be in contact with the convoy.

The force was organized by BdU as the result of an intercepted signal in Allied Convoy Cipher No. 3 dated 15 May, which B-Dienst forwarded on the 17th. The signal gave SC.130's position, course, and speed, as well as the identity of its close escort, B7.
⁴⁸
Here was an opportunity for BdU to gain vengeance for
die Katastrophe am ONS.5.
Accordingly, two patrol lines were established to be in position at 2000 on the 18th athwart the convoy’s course:
Donau I,
consisting of thirteen boats (two,
U-640
and U-657, had been sunk, unknown to BdU) from AK 4258 (56°03'N, 37°55'W) to AK 8141 (53°31, 35°25'W); and
Donau II,
consisting of twelve boats from AK 4944 (53°09'N, 35°15'W) to AK 8734 (5o°33’
N
, 33°35'W). In addition, eight boats coming out from Biscay bases or from at-sea refueling were to take up a patrol line from ED 2181 (5o°21'N, 33°25'W) to DD 2769 (48°39'N, 32°35'W) under the name
Oder
(the river). Although BdU’s orders creating these dispositions were not decrypted by the Allies until the 19th through the 22nd, according to the Bletchley Park Hut 8 record, thus providing no cryptographic intelligence on the basis of which to divert the convoy from danger, the prescient Rodger Winn in OIC’s Tracking Room somehow knew of these dispositions anyway, since on the 17th he wrote in his Special Intelligence Summary: