14–15 December Convoy HG 76 sailed from Gibraltar on 14 December 1941, in company with a small convoy bound for Cape Town. Agents across the bay, reported the composition, escort strength and departure time of the convoy. BdU was confused by an agent report that the convoy had returned to port. The first sightings of Convoy HG 76 were made by and , both to the Mediterranean and about to pass the Straits.
U-77 sank one ship from the Cape Town convoy, but
U-74 was unable to attack Convoy HG 76;
Swordfish aircraft of
RAF Gibraltar Command were escorting the convoy and on three occasions during the night of drove off the U-boats. The boats formed a patrol line south of
Cape St Vincent but Convoy HG 76 passed through the line without detection. At
Hudson and
Catalina aircraft took over from the Swordfish and for the next two days co-operated with the 802 NAS Martlets on
Audacity, forcing U-boats to submerge. was detected on a routine
anti-submarine sweep by a
Short Sunderland from Gibraltar late in the day; next morning it was detected on
Asdic by
Nestor and sunk at
16–18 December At noon on 16 December, Convoy HG 76 was sighted and its position reported by a Focke-Wulf Condor of I/KG 40 patrolling from
Bordeaux, which guided
U-108 to the convoy to begin reporting its position to other U-boats. During the night of the wolf pack closed in and
U-574 was ordered to the area; by morning on 17 December, the convoy had passed beyond the range of Gibraltar-based aircraft and four U-boats made contact,
U-67 and
U-108 being forced away from the convoy. Just after a Martlet from
Audacity sighted a surfaced U-boat about from the convoy and circled over the area for the escort ships to gain a good radar fix; a corvette made an Asdic attack to no apparent effect. At on 17 December,
Stanley sighted
U-131 on the surface and Walker ordered a Martlet to attack while
Stork, with
Pentstemon and the three destroyers, made their best speed to the location. The Martlet pilot dived towards the U-boat and both opened fire at the same time, the Martlet being shot down and the pilot killed. The British ships opened fire at extreme range, then
U-131 was driven to the surface and sunk. Observers saw the crew of
U-131 abandon the vessel before it sank at and took on survivors who said that they had been shadowing the convoy (claiming to have spent the previous night inside the convoy,
homing other U-boats) and had been the U-boat attacked earlier. On the night of the U-boats attacked again but failed to torpedo any ships;
U-107 was forced under water by
Pentstemon and after a failed torpedo attack,
U-67 was forced to retire by
Convolvulus. At on 18 December,
Stanley gained an Asdic contact at and fifty
depth charges were dropped by the escorts. After thirty minutes
U-434 surfaced and the crew abandoned ship just before it rolled over and sank, north of
Madeira, of the crew being rescued and taken prisoner. Before noon, the radar on
Audacity indicated two aircraft and Martlets were scrambled to intercept but the guns on both aircraft jammed and the Condors escaped. The rest of the day was quiet but the Admiralty signalled that three more U-boats were en route. In the early hours of
Stanley sighted
U-574 astern at sent a sighting report, was hit by a torpedo and blew up.
Stork following behind, swung behind the stern of
Stanley, gained an Asdic contact and dropped a pattern of depth charges, then turned after to attack again. A U-boat shot to the surface ahead and a chase began; Walker tried to ram the U-boat but found that it could turn inside the turning circle of
Stork, nearly as fast. The ship fired on the U-boat, illuminated it with snowflake
flares and managed to ram it just forward of the conning tower, scraping over the hull of the submarine. As the U-boat emerged from under the stern, depth charges set for
shallow were dropped, blowing up the U-boat. The bows of
Stork were crushed and bent sideways and the Asdic dome under the hull was smashed. Soon afterwards,
U-108 torpedoed
Ruckinge, which was abandoned and sunk later by
Samphire. Condors arrived, one was shot down in another head-on attack and a second aircraft was damaged. When more Condors reached the convoy in the afternoon, a Martlet pilot made such a determined head-on attack that he collided with the Condor, destroying it and coming back with its aerial round his tail-wheel; the night of was quiet.
19–21 December At a Condor appeared to shadow the convoy and a Martlet chased it away before returning for lack of fuel. In the afternoon a Martlet spotted two U-boats and the convoy made an emergency turn. The U-boats were forced to submerge and Martlets patrolled overhead keeping them down for as long as their fuel lasted. It was so dark that the aircraft were guided to the flight deck with hand torches and again the night was quiet.
U-107 maintained contact and the wolf pack was joined by , (commanded by the ace
Engelbert Endrass) and from Bordeaux and the three original wolf pack boats
U-67,
U-107 and
U-108 re-joined by 21 December. On 21 December, 802 NAS was down to three operational Martlets, take-off and landing was dangerous in the heavy swell and the pilots were very tired. After the last patrol, the commander of
Audacity ordered the ship out of the convoy to the starboard as usual but no escorts could be spared. At during the night of 21/22 December, a ship at the rear of the convoy was torpedoed by
U-751 and nearby ships fired snowflakes, illuminating the area to both sides.
U-567 saw the silhouette of
Audacity at close range torpedoed it at . As the carrier sank by the stern, two more torpedoes from
U-751 hit it, a big explosion blew off the bows and the ship began to sink at the head. At
Audacity sank head first at 43°45'N, 19°54'W, about west of
Cape Finisterre.
22–23 December At on the night of
U-567 was sunk by depth charges from
Deptford, two hours after gaining an Asdic contact;
Deptford then collided with
Stork, damaging them both.
U-67 fired torpedoes at a
CAM ship but missed. During 22 December,
U-71 and
U-751 remained in contact, to be joined by
U-125 (en route to America), while Convoy HG 76 was reinforced by the destroyers and . At a
Liberator of
120 Squadron, 19 Group
Coastal Command based at
RAF Nutts Corner in Ireland ( away) arrived over the convoy and saw off a Condor. After two hours the Liberator attacked a U-boat and at was relieved by a second Liberator, which forced another three U-boats to submerge. The Liberator turned for home with minimal fuel but next day the convoy came into range of continuous air support. On 23 December, Dönitz, shaken by the loss of five U-boats and the lack of success against the convoy, called off the attack,
U-67,
U-107,
U-108 and
U-751 returned to bases in France. ==Aftermath==