HMS Affray sank in the English Channel in 1951 during a training exercise, killing all 75 people aboard.
Affray was an Amphion-class submarine, also known by the designation A-class, designed for long-range operations in the Pacific. It entered Royal Navy service after World War II and was conducting an exercise on 16 April 1951 when it failed to return to port. The submarine was carrying a regular crew and several trainees.
A large search operation followed, involving Royal Navy ships and aircraft. Affray was eventually located on the seabed in the English Channel, west of Alderney. Investigators concluded that its snorkel became damaged or detached, allowing seawater to enter the submarine and causing the loss.
The wreck lies in deep water and was declared a protected site. Affray is often confused with other Royal Navy submarine losses, including HMS Thetis, which sank during trials in 1939, and HMS Truculent, lost after a collision in 1950.