HMS Unseen (P51)

HMS Unseen (P51) was a British U-class submarine of the Royal Navy, built by Vickers-Armstrongs at Barrow-in-Furness. She was laid down on 21 February 1941, launched on 20 November 1941, and commissioned on 30 January 1942.

During World War II, Unseen served primarily in the Mediterranean theatre. She sank several enemy vessels, including the Italian merchant ships Francesco Crispi, Cadamosto, and Giovanni da Verrazano. She is also credited with sinking the Italian submarine Onice.

In August 1942, Unseen attacked and severely damaged the Italian cruiser Armando Diaz off the coast of Tunisia. The cruiser was later sunk by a British submarine.

HMS Unseen was decommissioned in 1946 and scrapped in 1949. Her wartime service earned her several battle honours.