The U-Boat war was not going well for the Germans. Losses had continued to mount since the disastrous month of May when they had lost 41 boats – in the whole of 1942 they had lost 86 boats. The yearly total for 1943 would 238. Much improved radar and weaponry, combined with improved tactics and better co-ordination between Allied surface vessels now made it a very hazardous proposition to attempt to attack convoys. Many U-boats were attacked so quickly that they did not know what had hit them.
The attack on U-73 is probably typical. She was an experienced boat with an experienced commander with over a year of combat experience. On the 13th December she had survived being rammed – she had only lost her deck gun. On the 16th she ran out of luck. Or perhaps she was lucky – because there were 34 survivors out of a crew of 50. Most U-boats were now sunk with no survivors.
On this occasion the Royal Navy Intelligence Division, which interrogated the prisoners after they were brought in by the US Navy, was able to piece together the attack from their perspective:
At about 1530 on 16th December, “U 73″ sighted a convoy and closed to attack. A T.5 torpedo was fired from Tube II and, according to the prisoners, hit a destroyer. The prisoners were astonished to see the entire convoy come to a full stop at the time of the attack.
The U-Boat then fired a spread of three T.3 torpedoes from Tubes I, III and IV. It was stated that one of these scored a hit on an 8,000-ton merchant vessel, one hit a corvette, and the third, its rudder jammed, circled around and above the U-Boat herself, causing considerable consternation among the crew.
The prisoners believed that the merchantman had been sunk and the corvette damaged. (N.I.D. Note. S.S.” J.S. Copley,” 7,176 tons, was torpedoed by a U-Boat on 16th December, 1943, in position 35° 54′ N., 00° 53′ W. A tug was dispatched to her aid and she was towed into harbour, reaching Oran on 17th December. There is no record of an escort ship being damaged.)
After making this attack, “U 73” submerged to a depth of about 40 m. (131.2 ft.).
(i) Depth-Charge Attack About three hours after attacking the convoy. “U 73” was proceeding submerged when she was taken completely by surprise by a destroyer. Some prisoners were violent in their criticism of Deckert, saying that he had been careless about maintenance, with the result that the rudders and motors were too noisy. Others blamed him for proceeding at too shallow a depth.
The destroyer dropped a pattern of depth-charges which exploded below the U-Boat, inflicting considerable damage. There was water entry forward between the bow torpedo tubes. A sea inlet valve of the Diesel cooling system was fractured causing water to flow into the motor room. “U 73” lost trim and sank to a depth that was variously estimated to have been between 160 and 230 m. (524.8 and 754.6 ft.).
(ii) Gunfire Attack Deckert ordered all tanks blown and, with the aid of one main motor, “U 73” broke surface at about 1900. No enemy ship was visible and full speed ahead on the Diesels was ordered. Suddenly searchlights from surface craft illuminated the U-Boat and she was immediately engaged by gunfire. A number of hits were scored on the bridge and several of her crew were killed.
The order to abandon ship was given and shortly thereafter, the U-Boat sank. One prisoners stated that “U 73” was not scuttled but was shipping so much water through rents in her pressure hull that she sank twenty minutes after being shelled. No signal was sent to Control regarding the sinking.
N.I.D. Note. On the afternoon of 16th December, 1943, U.S.S. “Wolsey” was proceeding with U.S.S. “Edison” and U.S.S. “Trippe.” At 1815, “Wolsey” obtained asdic contact on a submerged U-Boat and made a depth-charge attack. The U-Boat was forced to the surface. The destroyer regained contact with radar and “Wolsey” and “Trippe” opened fire. The U-Boat sank at 1935 in position 36° 09′ N., 00° 50′ W.)
For all the reports on the action see U-boat Archive.