Black May (49 page)

GRÄTZ
: [I believe] there must be something.

K
OHLER:
There must be something. If my mother knew! In that second I even confessed. I have never told anyone this, but I believe in God and in the resurrection of the soul. The Church has had a good influence on me. Without the Church I should have become a bad man. I told my wife I would try and remain in the Catholic Church. I said my prayers till I was seventeen years old, and even later, and during this last patrol I prayed three times, in the evening. I prayed that my wife and child should live and that I should come through this patrol. I prayed when I was rescued too. I believe in life after death.

Recorded 29 April 1943
⁶³

K
LOTZSCH:
It’s a tragedy. The whole business of U-boat sailing has simply become a job for convicts.

A
RENDT:
Well, that’s just about how you’re treated; if you do anything at all, you’re locked up.

Recorded 13 May 1943
⁶⁴

A
RENDT:
I don’t want to go to sea anymore. I’m fed up with it. I had intended to get married now.

Recorded 14 May 1943
⁶⁵

K
LOTZSCH:
Well, I’m not sorry that the damn business is finished.

Recorded 13 May 1943
⁶⁶

K
LOTZSCH:
It gets worse and worse, all the U-boat men are grousing.

M
ARCH:
Now it practically amounts to this: as soon as one boat is put into commission, another one is lost at the same moment.

Recorded 26 May 1943
⁶⁷

K
LOTZSCH:
Things look very bad for us. The boats are being sunk one after the other.

Recorded 13 May 1943
⁶⁸

R
AHN:
To tell you the truth, I haven’t much hope. They’ll crush us in time.

Recorded3 May 1943
⁶⁹

F
OLLOWING THE EPIC BATTLE
for ONS.5, nearly 600> Allied merchant ships in fourteen convoys crossed the Atlantic during the
remaining three weeks of May. Of that number only
six
ships were sunk by U-boats. Where the U-Bootwaffe crews were concerned, the startlingly low number did not result from their lack of trying; at Dönitz’s urging, they fought desperately to get back into the game. But it was too late. Both the initiative and the numbers had passed to the Allies. There were now too many experienced close escort and Support Group vessels in the convoy lanes. And overhead there were too many shore-based bombers, not to mention at this date carrier-borne British Fairey Swordfish bombers and Martlet (Grumman
F4F4
Wildcat) fighters and American Grumman TBF—1 Avenger bombers: it was during these weeks that such aircraft from American-built escort carriers achieved the first singlehanded destruction of a U-boat. These weeks also saw the first successful employments of the American airborne homing torpedo code-named Mark XXIV Mine and of the British “R.P.” solid-head rocket projectile. It was all too much for the U-boats, once the aggressors, now left panting heavily in the wake of events. And many went down to sodden deaths. In this chapter our narrative will examine briefly those particular convoys that defined transatlantic traffic during the last three weeks of May, the major aircraft actions outside the Bay of Biscay, and, finally, U-boat losses elsewhere in the Atlantic and Outer Seas.

The surviving U-boats that had operated against ONS.5 moved off to the east and south. Approximately fifteen boats were still capable of operations; ten would shortly be operational after reprovisioning from two milch cows; and nine were on their way back to base. Western Approaches had no information about these movements, since decryptions of German radio traffic were still trying to catch up to events following the cryptographic intelligence blackout from 26 April to the afternoon of 5 May. Suspecting, however, that packs were still operating in the general area of the ONS.5 battle, the next westbound convoy in the eight-day cycle, ONS.6, departing 30 April, was routed to the west of those possible concentrations. Surface protection was provided the convoy by Escort Group
B6,
consisting of one destroyer, H.M.S.
Viscount
(S.O.), five corvettes, and two trawlers; and air cover flew out of Iceland beginning on 3 May. Despite its evasive route, the convoy
did not escape enemy detection. Two U-boats, U
—418
and U—952, from a new
Gruppe Isar
[after the river] forming between Greenland and Iceland, sighted the convoy on the morning of 6 May, when the convoy was at 60°15‘N, 24°20
‘W.
Their reporting signals to Berlin were DFed by
Viscount
and shore stations, leading CinCWA to increase the air cover by noon. By 2100,1 aircraft had made ten U-boat sightings, two 55 and 73 nautical miles ahead of the convoy columns, seven between 18 and 32 miles abaft the starboard beam, and one 58 miles astern. Several attacks resulted.

Meanwhile, on the surface, one of the corvettes had made a visual sighting on the starboard quarter at 1946. The abundance of air threat, excellent intercommunication between surface and air units, and an evasive alteration of course at 2300 had the desired effect of shaking off the shadowing boats. A second alteration at noon on the 7th avoided boats known to be to the north. The 8th was quiet until dusk, when HF/DF intercepts suggested that the U-boats were closing the convoy again, and
Viscount
sighted a conning tower breaking the surface at a range of 7,000 yards. She pursued, the U-boat dived, and she dropped a ten-charge pattern over the swirl without result. The U-boats backed off, apparently made wary, if not unnerved, by the forces arrayed against them, and the night that followed was uneventful.

At 0700 on the 9th, the convoy’s protective screen was enlarged by the arrival of the “cavalry,” a Support Group (Fourth Escort Group) made up of destroyer H.M.S.
Faulknor
(SO), two other destroyers, and one of Britain’s new escort carriers, H.M.S.
Archer.
But by that time the danger was past and, after 48 hours, the Support Group disengaged to join Convoy ON.182. The ships of ONS'.6 then proceeded to their destinations without further incident. The convoy’s safe passage through the now-closing Air Gap where
Gruppe Fink
had gathered its predecessor convoy in a deadly embrace was a clear signal of the new dispensation that prevailed.
¹

In Berlin, BdU was aware from sailing cycles that a pair of east-bound convoys were due to depart on or about the same date in early
May, one a slow-moving SC convoy from Halifax, the other a faster HX convoy from New York. In anticipation of their crossing longitude 42°W at some time on 8 May, Dönitz/Godt formed two patrol lines stretching 550 miles across their probable courses: Group
Rhein
[the river], formerly
Amsel
III and IV, consisting of ten boats spaced at twenty-mile intervals from 47°33'N, 40°55'W to 43°57'N, 4o°o5'W; and Group
Elbe
[after the river], consisting of seventeen boats, mostly ex-ONS.5 operation, stationed at the same spacing from 52°45'N, 43°55'W to 47°51'N, 41°05'W.
²
Early in the game, the German B-Dienst radio monitoring and cryptanalysis service that so troubled Francis Harry Hinsley in Hut 8 at Bletchley Park learned from decryptions of Allied Naval Cipher No. 3 that on 3 May, eastbound convoy HX.237 was positioned at about 40°50'N, 67° (31–49'?) W, steaming on a course of 056°, speed 9.5 knots; and that on 5 May, eastbound convoy SC.129 was at position 44°50’
N
, 47°01
‘W,
course and speed unknown.
³
It was likely that the faster convoy HX.237, even if its departure was the later of the two, would be the first to cross the line that Dönitz/Godt had drawn in the sea.

In the evening of 6 May, B-Dienst informed BdU that as of 2130, HX.237 was in BC 7684 (43°56'N, 48°27'W). That information was quickly relayed to the
Rhein
and
Elbe
patrol lines.
⁴
Further data learned by B-Dienst on the 7th revealed that HX.237 had turned toward the south on a course of 128°, and that SC.129 was on a base course toward the east.
⁵
This intelligence that the two convoys were taking a more southerly route than expected, which would cause HX.237 to elude the patrol lines altogether and SC.129 merely to brush the southern tip of
Rhein,
had three immediate effects: (1) BdU ordered the
Rhein
boats to move at best speed on a course of 120° so as to position that group’s southernmost boat at 39°45'N, 35°02'W; and at the same time, the
Elbe
boats were directed to take the same course of 120° at ten knots in order to intercept SC.129; though BdU conceded that, “No clue to the [present] position of this convoy is in hand.”
⁶
(2) The six boats of Group
Drossel
(Thrush), which had been operating on the coastwise West Africa-Gibraltar-U.K. lanes, were ordered west to reinforce
Rhein
and
Elbe.
And (3) Donitz/Godt demanded to know
“how the enemy was able to intercept our patrol strip” and to divert the two convoys around it.

BdU considered every possible explanation, from detection of the patrol lines by aircraft, to DFing of U-boat radio traffic during the Battle for ONS.5, to the possibility “considered unlikely, that the enemy has cracked our ciphers”—still, BdU ordered an immediate change in Enigma settings. Whatever the reason, BdU stated, “this almost circular detour remains critical.”
⁷
It is ironic that this is one of the few occasions in 1943 when, in fact, decryption of Enigma played no role in the diversion of convoys around wolfpacks. It appears that prior to the movements of the two convoys on the 6th and 7th the Allies had no knowledge of the formation or positions of
Rhein
and
Elbe.
The first British decrypt of German traffic pertaining to the formation of
Rhein
in the existing records is a message intercepted at 1015 on the 7th but not decrypted until 1304 on the 9th; and the first mention of
Elbe
was intercepted at 1320 on the 12th and not decrypted until 1016 on the 14th.
⁸
Very probably, the two convoys were given southerly routes to evade U-boat concentrations thought to be east of Newfoundland and building up between Greenland and Iceland as well as to provide better flying weather for the aircraft aboard escort carrier H.M.S.
Biter,
which, in the course of events, would offer cover to both HX.237 and SC.129.

Two ocean escort groups were assigned to HX.237: C2, consisting of the destroyer H.M.S.
Broadway
(Lt.-Cmdr. E. H. Chavasse, R.N., SO), a frigate, four corvettes (three of them Canadian), a trawler, and a tug; and Escort Group 5, acting as a Support Group, consisting of
Biter
(Capt. E. M. C. Abel-Smith, R.N., SO) and three destroyers. Owing to heavy fog, C.2 relieved the local escort a day later than planned, at 1400 on 7 May.
Biter
and her escorts were even further delayed, not joining until the 9th, in thick weather unsuitable for flying, but on the 7th and 8th, in better weather, her aircraft had flown out to the convoy to make close patrols ahead and astern and thus “hearten the Masters and their crews.” The merchant argosy itself was made up of thirty-eight ships in company and nine stragglers. Two stragglers put back to St. John’s, four rejoined the convoy, and three,
Fort Concord, Brand,
and
Sandanger,
continued independently; these three would be sunk on the 12th, the only casualties among the vessels actually or nominally part of HX.237: once again it was proved how vital it was for merchant vessels to keep their stations in a convoy.

At 1300 on the 9th, thanks to BdU’s new dispositions, U-359 (Oblt.z.S. Heinz Förster) of the
Rhein
group sighted the main body in 41°09'N, 26°54'W and, on BdU’s order, became its shadower. The U-boat’s transmissions were DFed by
Broadway
, who sent the corvette
Primrose
down the bearing, where she got a sighting and, after the boat dived, dropped a ten-pattern, with no evidence sequent. Meanwhile, Chavasse ordered the convoy to alter course 40° to starboard. More HF/DF bearings were acquired later in the day, suggesting that at least two U-boats were in contact with the convoy, but no sightings resulted, and because of the continued milky air, the nine Swordfish and one Martlet of 811 Naval Air Squadron aboard
Biter,
steaming on station astern, could not assist in the hunt. (There had been three Martlets originally, but on the 7th two Martlets had failed to return from patrols, though vigorous efforts were made to home them back. Lost, they both made forced landings alongside ships, a straggler and a trawler, and their pilots were picked up. The two ships were 90 miles northeast of the convoy! Three days later, a Swordfish was lost and its crew rescued in exactly the same way.)

The next morning, the 10th, in slightly more diaphanous air, U-403 (Kptlt. Hans Clausen), following C2's tug on the surface, sighted the convoy, and at 1647 was sighted herself to starboard by the escort screen. Two corvettes made revolutions after the intruder, and
Biter
was able to launch Swordfish “M,” which reached the still-surfaced boat six miles distant before the corvettes. Raked by machine-gun fire when 1,500 yards from the conning tower, the fabric-skinned biplane banked hard out of range; then, as the U-boat dived, it returned to the attack at maximum speed of 120 knots, approaching from the U-boat’s port quarter at an angle of 45° to track, and from a height of 60 feet dropped four Mark XI D/Cs set to 24 feet and spaced 60 feet apart. They missed astern. The surprised U-boat, having survived the attack, signaled BdU that she had been engaged by a
wheeled
aircraft. This was
certainly news to BdU, which had just signaled the
Rhein
boats that they need not fear aircraft, since the convoy was out of the range of shore air bases, so BUT LITTLE AIR CAN JOIN THE CONVOY.
⁹
But
Biter
s flight deck, built on an American merchant hull, had been able to offer the ultimate surprise, a hard-surface landing gear aircraft flying from a midocean runway.

The escort carrier (CVE) was a warship type coincidentally first produced by both the RN and USN in June 1941. In both instances a flight deck was mounted on a merchant ship hull. The RN type, H.M.S.
Audacity,
embarked six Martlet fighters on the converted merchant ship
Hannover
captured from the Germans. Assigned to the U.K.-Gibraltar convoys, she had an outstanding six-month career, destroying five Luftwaffe aircraft, sighting nine U-boats, and on 17 December 1941 sharing in the sinking of
U
-131 (Korv. Kapt. Arend Baumann) with the 36th Escort Group (Cmdr. Frederic John Walker, R.N., SO), though the attacking Martlet and pilot were lost to the U-boat’s gunfire. While escorting Convoy HG.76 on the night of 21–22 December 1941,
Audacity
was struck by three torpedoes from U—751 (Kptlt. Gerhard Bigalk) and sunk.
¹⁰