TYPE: Long-range patrol bomber flying boat

ACCOMMODATION: Crew of seven

POWER PLANT: Two Pratt & Whitney R-2800 radial engines, rated at 2,100 hp each

PERFORMANCE: 205 mph

COMMENT: The Martin PBM-5 “Mariner” was an American patrol bomber flying boat of WW II. It was designed to complement the Consolidated PBY “Catalina” in service with the US Navy.
Designed in 1937, the Model 162 continued the rivalry which had sprung up between Martin and Consolidated by challenging the latter company’s PBY “Catalina”.  A somewhat later design than the PBY, the Martin 162 was in due course to demonstrate a marked superiority of performance, an although it served in smaller quantities than the PBY during WW II, it continued to give important service for many years after 1945.
The Model 162 design featured a deep hull with a gull wing and two Wright “Cyclone” engines. To test the handling qualities of the design, Martin built a single-seat, quarter-scale model known as the Model 162A, an on June 1937, the US Navy places a contract for a single full-scale prototype, to be designated XPBM-1. First flown on February 1939, the XPBM-1 had 1,600 hp Wright R-2600-6 engines an provision for nose and dorsal turrets plus additional gun positions at the waist and tail position. The XPBM-1 was designed to carry 2,000 lb bombs or depth-charges. It had retractable stabilizing floats under the wing and a flat tailplane with outrigged fins. Later, dihedral was added to the tailplane, canting the fins inward to give the Martin flying boat one of its most striking characteristics. At the end of 1937 the Navy ordered 20 production model PBM-1s, for which the name “Mariner” was eventually chosen. All aircraft were completed by April 1941 and went into service during 1941.
On November 1941, orders were placed with Martin for 379 PBM-3 “Mariners” and these appeared, from 1942 onwards, in several different versions. All “Mariners” from the -3 model onward had fixed, strut-braced wing floats and lengthened engine nacelles, the latter providing stowage for bombs or depth-charges. The basic PBM-3 had Wright R-2600-12 engines, and variants includes 50 unarmed PBM-3R transports with seats for 20 passengers, 274 PBM3Cs with standardized US/British equipment and 201 PBM-3Dswith Wright  R-2600-22 engines and improved armament and armor protection. Many of the PBM-3Cs and -3Ds carried search radar in a large housing above and behind the cockpit, and experience with the use of this radar led to development in 1944 of a long-range anti-submarine version, the Martin PBM-3S. A total of 156 of the latter variant were delivered, with R-2600-12 engines.
In 1943, the Martin XPBM-5 appeared with 2,100 Pratt & Whitney R-2800-22 or -34 engines, and production contracts were placed for this variant in January 1944. The PBM-5, delivered from August 1944 to the end of the war, had eight 0.50-in machine guns and AN/APS-15 radar. They were used as long-range reconnaissance aircraft and for the anti-submarine role. Production totaled 631 aircraft (Ref.: 23).