The Martin PBM Mariner was a patrol bomber flying boat of World War II and the early Cold War period. It was designed to complement the PBY Catalina in service. 1,366 were built, with the first example flying on February 18, 1939 and the type entering service in September 1940.
The first PBM-1s entered service with Patrol Squadron FIFTY-FIVE (VP-55) of the United States Navy on 1 September 1940. Prior to the outbreak of World War II, PBMs were used (together with PBYs) to carry out Neutrality Patrols in the Atlantic, including operations from Iceland. Following the Japanese Attack on Pearl Harbor, PBMs were used on anti-submarine patrols, sinking their first German U-Boat, U-158 on 30 June 1942. In total, PBMs were responsible, wholly or in part, for sinking 10 U-Boats during World War II. PBMs were also heavily used in the Pacific, operating from bases at Saipan, Okinawa, Iwo Jima and the South-West Pacific.