the South West Pacific. The United States Coast Guard acquired 27 Martin PBM-3 aircraft during the first half of 1943. In late 1944, the service acquired 41 PBM-5 models and more were delivered in the latter half of 1945. Ten were still in service in 1955, although all were gone from the active Coast Guard inventory by 1958 (when the last example was released from CGAS San Diego and returned to the U.S. Navy). These flying boats became the backbone of the long-range aerial search and rescue efforts of the Coast Guard in the early post-war years until supplanted by the P5M Marlin and the HU-16 Albatross in the mid-1950s. PBMs continued in service with the U.S. Navy following the end of World War II, flying long patrol missions during the Korean War. It continued in front line use until replaced by its successor, the P5M Marlin. The last Navy squadron equipped with the PBM, Patrol Squadron Fifty (VP-50), retired them in July 1956. The British Royal Air Force acquired 32 Mariners, but they were not used operationally, with some returned to the United States Navy. A further 12 PBM-3Rs were transferred to the Royal Australian Air Force for transporting troops and cargo. The Royal Netherlands Navy acquired 17 PBM-5A Mariners at the end of 1955 for service in Netherlands New Guinea. The PBM-5A was an amphibian with retractable landing gear. The engines were Pratt & Whitney R-2800-34. After a series of crashes, the Dutch withdrew their remaining aircraft from use in December 1959. Variants XPBM-1 (Model 162) Prototype. Powered by two 1,600 hp (1,194 kW) R-2600-6 engines. PBM-1 (Model 162) Initial production version. 5× .50 inch (12.7 mm) machine guns. Two R-2600-6 engines; 21 built. XPBM-2 (Model 162) Conversion of one PBM-1 as experimental catapult-launched long-range strategic bomber. PBM-3 (Model 162B) Improved version. 1,700 hp (1,270 kW) R-2600-12 engines; 32 built. PBM-3R (Model 162B) Unarmed transport version of PBM-3. 18 new build plus 31 converted from PBM-3. PBM-3C (Model 162C) Improved patrol version with twin .50 in machine guns in nose and dorsal turrets, and single guns in tail turret and waist positions. AN/APS-15 radar in radome behind cockpit; 274 built. PBM-3B (Model 162C) Designation for ex-RAF Mariner GR.1A after return to U.S. Navy. PBM-3S (Model 162C) Dedicated anti-submarine aircraft with reduced armament (2× fixed 0.50 in machine guns in nose, single machine gun in port waist position, and