1 Apr 1942
The U-77 was attacked in the Mediterranean by a Swordfish aircraft, leaving it badly damaged and unable to dive.

4 Jul 1942
HMS Thrasher (Lt. H.S. Mackenzie, DSO, RN) attacks U-77 with three torpedoes in position 32º48'N, 33º36'E. All torpedoes missed. Thrasher surfaces to engage with gunfire but the Germans crash-dive.

13 Nov 1942
The depth charge attack on 13 Nov, 1942 by from the British corvettes HMS Lotus and Poppy credited with sinking the U-605 was in fact against the U-77 which escaped with little damage (Sources: 1987-07-01, FDS/NHB)

28 Mar 1943
The sinking of U-77 At 11.25 hours, the boat was spotted by a Hudson Mk.VI (48 Sqn RAF/L, pilot F/O J.B. Harrop) on patrol east of Cartagena in position 37°42N/00°10E and immediately crash-dived when the aircraft attacked, dropping depth charges just ahead of the swirl. Oil and bubbles could be seen on the surface and in fact water entered through a serious leak in the diesel engine room, forcing U-77 to surface later and left her unable to dive. Hartmann reported his situation to the FdU while heading towards Toulon and was instructed to enter the neutral Alicante for repairs under international maritime law. U-380 (Röther) was ordered to meet the boat to take off most of its crew to avoid internment in Spain, but the Hudson Mk. IIIA T9430 (233 Sqn RAF/L, F/O E.F. Castell) found U-77 earlier between Cabo San Antonio and Ibiza at 17.45 hours. The boat was attacked with four depth charges despite of fierce AA fire, strafed with 3000 rounds in several runs and a single A/S bomb was dropped that exploded 15 yards behind the stern – the pilot was later awarded the DFC. At dusk, the badly damaged boat managed to escape further attacks and headed for Alicante, but during the night both electrical engines broke down and the immobile U-77 began to settle, sinking at 01.15 hours on 29 March south of Cape Nao, Spain – the wreck was located in a depth of 80 meters in 38°33.334N/00°14.875E. All crew members abandoned ship in one rubber dinghy and some makeshift rafts made from deck planks, but the commander and 37 crew members died of exposure or drowned, only nine survivors were found several hours later by a Spanish fishing vessel from Denia, landed at Altea on 30 March and eventually repatriated. 36 bodies washed ashore and were buried in Spain, the commander and four men in Altea and 31 in Calpe – in 1983 they were reinterred at the cemetery at Cuacos de Yuste, Provincia de Cáceres, Spain.

4 recorded attacks on this boat.