The Martin PBM Mariner was an American patrol bomberflying boat of World War II and the early Cold War period. It was designed to complement the Consolidated PBY Catalina in service. A total of 1,366 were built, with the first example flying on 18 February 1939 and the type entering service in September 1940.
In 1937 the Glenn L. Martin Company designed a new twin-engined flying boat, the Model 162, to succeed its earlier Martin P3M and complement the PBY Catalina. It received an order for a single prototypeXPBM-1 on 30 June 1937. This was followed by an initial production order for 21 PBM-1 aircraft on 28 December 1937.
To test the PBM's layout, Martin built a ⅜ scale flying model, the Martin 162A Tadpole Clipper with a crew of one and powered by a single 120 hp (89 kW) Chevrolet engine; this was flown in December 1937. The first genuine PBM, the XPBM-1, flew on 18 February 1939.
The aircraft was fitted with five gun turrets, and bomb bays that were in the engine nacelles. The gull wing was of cantilever design, and featured clean aerodynamics with an unbraced twin tail. The PBM-1 was equipped with retractable wing landing floats that were hinged outboard, with single-strut supported floats that retracted inwards to rest beneath the wing, with the floats' keels just outboard of each of the engine nacelles. The PBM-3 had fixed floats, and the fuselage was three feet longer than that of the PBM-1.
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, with the last USN squadron equipped with the PBM, Patrol Squadron Fifty (VP-50), retiring them in July 1956.
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 2,100 hp (1,600 kW) 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 single gun in tail turret) and increased range; 94 built as new plus 62 conversions.
PBM-3D (Model 162D)
Patrol bomber with increased power (two 1,900 hp (1,417 kW) R-2600-22s) and increased armament (twin 0.50 in machine guns in nose, dorsal and tail turrets, plus two waist guns). 259 built.
PBM-4 (Model 162E)
Proposed version with two 2,700 hp (2,015 kW) Wright R-3350 engines; unbuilt.
PBM-5 (Model 162F)
Version with 2,100 hp (1,566 kW) Pratt & Whitney R-2800 engines; 628 built.
PBM-5A (Model 162G)
Amphibian version of PBM-5, with retractable nosewheel undercarriage; 36 built plus four conversions.
Mariner I
British designation for 32 PBM-3B supplied to the Royal Air Force.
National Navy of Uruguay purchased three PBM-5S2s in 1956, with the last retired on 3 February 1964.
Survivors
United States Navy PBM-5A (Bureau Number (BuNo) 122071) is the only surviving Mariner. It is on loan from the National Air and Space Museum in Washington, D.C. and is currently on display at the Pima Air & Space Museum adjacent to Davis–Monthan Air Force Base in Tucson, Arizona. Operated by the USN between 1948 and 1956, it is painted in the markings of Transport Squadron 21 (VR-21) and coded RZ 051 of the early 1950s.
Although only one complete Mariner aircraft exists, another aircraft (PBM-5 BuNo 59172) lies upside down under Lake Washington. It crashed on 6 May 1949, and after a number of unsuccessful attempts to recover the wreck over the following decades it is now used as a training site for divers.
The Model 162A (registered NX19168), the piloted ⅜ scale test aircraft, is on display at the Baltimore Museum of Industry.
Accidents and incidents
On 30 November 1944, a U.S. Navy PBM-5 crashed into Mount Tamalpais in northern California killing eight naval aviators and naval aircrewmen. The aircraft had taken off from Naval Air Station Alameda and was part of a larger flight headed for Hawaii when it developed engine trouble shortly after takeoff.
In December 1945, United States Navy PBM-5 (BuNo 59225), based at Naval Air Station Banana River, Florida was believed to have been destroyed in a mid-air explosion off the coast of Florida near The Bahamas, while searching for the missing TBM Avengers of Flight 19 from Naval Air Station Fort Lauderdale, Florida.
On 10 September 1958, Mariner P-303 was being ferried to the Netherlands from Biak, Indonesia. Due to technical problems, a forced landing was carried out at Abadan, Iran. About two weeks later, repairs had been accomplished, and the aircraft took off. Shortly after takeoff, an oil leak was observed on engine number one. While on finals for landing at Abadan, the aircraft suddenly lost height and crashed, killing all aboard. It appeared that the remaining propeller reversed thrust, causing the crew to lose control.
On 9 November 1958, a PBM-5 Mariner (CS-THB, named "Porto Santo") of the Portuguese airline ARTOP (Aero-Topográfica) disappeared on a scheduled passenger flight from Cabo Ruivo, Lisbon, Portugal to Funchal, Madeira. The last communication from the aircraft (when it was about 13°W) was a radio message code "QUG", meaning "I am forced to land immediately". No trace has ever been found of the aircraft, its six crew or 30 passengers.
Specifications (PBM-1)
Data from Jane’s Fighting Aircraft of World War II
General characteristics
Crew: Seven
Length: 79 ft 10 in (23.50 m)
Wingspan: 118 ft 0 in (36 m)
Height: 27 ft 6 in (5.33 m)
Wing area: 1,408 ft² (131 m²)
Empty weight: 33,175 lb (15,048 kg)
Loaded weight: 56,000 lb (25,425 kg)
Powerplant: 2 × Wright R-2600-6 14-cylinder radial engines, 1,600 hp (1,194 kW) each
Performance
Maximum speed: 178 kn (205 mph, 330 km/h)
Range: 2,600 nmi (3,000 mi, 4,800 km)
Service ceiling: 19,800 ft (6,040 m)
Rate of climb: 800 ft/min (4.1 m/s)
Armament
Guns: 8 × .50 in (12.7 mm) M2 Browning machine guns (two each in nose, dorsal and tail turrets, one each in blisters amidships)
