Designed in 1937, the Martin ‘Model 162’ was the replacement for Martin’s earlier open-cockpit P3M flying boats, which had been in service with the US Navy since 1931. The new Model 162 was a massive design and Martin built a quarter-scale, single seat model known as the ‘162A’ to test its flight characteristics. On June 30, 1937, the U.S. Navy ordered a single full-size prototype for flight testing. It was given the designation XPBM-1. The first flight of the prototype was on February 8, 1939 and in December the U.S. Navy placed an order for 20 of the new planes and it was given the name Mariner.

PBM stands for Patrol, Bomber, and the ‘M’ was the letter assigned by the U.S. Navy to all aircraft built by the Martin Aircraft Corporation. The PBM had two engines, each with a three-bladed propeller, and the elongated engine nacelles also had room for four 500-pound bombs or depth charges, or auxiliary fuel tanks.

The wingspan measured 118 feet and it was just under 80 feet from nose to tail. Defensive armament consisted of six machine guns located in the nose, dorsal, tail, and waist positions on the aircraft.

Later versions of the Mariner had improved engines with a four-bladed propeller, and they could carry up to eight 500-pound bombs, depth charges, or mines in the nacelles. The Mariners could also carry two torpedoes under the wings of the plane. A total of 1,366 PBM’s were built until production ceased in April 1949.

(Content provided by Dan Farnham)