HMS AFFRAY (Lt J Blackburn) was one of the first of the A class submarines, entering service in early 1945. AFFRAY was within a few days of the 6th anniversary of her launch when, during Exercise TRAINING SPRING, she was lost with all hands in Hurd Deep, a short distance from Alderney. She had dived 30 miles South of the Isle of Wight at 2115 on 16 April and was due to transit to a position 20 miles southeast of Start Point. She failed to report her position on 17 April and search operations were initiated as a consequence. Despite the efforts of several ships and submarines, she was not found and, on 19 April, she was considered lost. In addition to her ship company, a class of submarine officers under training and 4 Royal Marines were also embarked and were lost in the accident.

Her loss is still a matter of controversy and the exact reason for her loss may never be known as she is now protected as a grave for those who died in her. The most likely cause is that her snort mast broke off while she was at periscope depth and that the induction hull valve had failed to operate satisfactorily, resulting in water entering the submarine through a 10-inch hole. With her buoyancy destroyed, she would have sunk very quickly.