Martin P5M Marlin

The Martin P5M Marlin (P-5 Marlin after 1962), built by the Glenn L. Martin Company of Middle River, Maryland, was a twin-engined piston-powered flying boat entering service in 1951 and serving into the late 1960s in service with the United States Navy for naval patrol. It also served in the United States Coast Guard and with the French Navy. 285 were produced overall.

Martin P5M Marlin
Class Aircraft
Type Utility
Manufacturer Glenn L. Martin Company
Origin United States of America
Country Name Origin Year
United States of America 1948
Country Name Operational Year Retirement Year
France View
United States of America 1952 1967 View
ManufacturerName Production From Production To Quantity
Glenn L. Martin Company 285 View

The Marlin was designed as a gull-winged aircraft to place the engines and propellers high above the spray. Power was by two Wright R-3350 radial engines. The rear hull did not lift sharply from the water at the tail, instead rising up steadily, a Martin innovation; this gave the aircraft a longer base of flotation and reduced "porpoising" over waves.

The prototype had nose and tail turrets with twin 20 mm (0.79 in) cannons in each, as well as a dorsal turret with two 0.5 in (12.7 mm) M2 Browning machine guns. The cockpit area was the same as the Mariner's. It first flew in 30 May 1948.

The first of 167 production P5M-1 aircraft was produced in 1951, flying on 22 June 1951. Changes from the prototype included a raised flight deck for improved visibility, the replacement of the nose turret with a large radome for the AN/APS-44 search radar, the deletion of the dorsal turret, and new, streamlined wing floats. The engine nacelles were lengthened to provide room for weapons bays in the rear.

The P5M-1 was followed by 116 P5M-2 planes. These had a T-tail to put the tail surfaces out of the spray, an AN/ASQ-8 MAD boom at the rear of the tail-tip, no tail guns (the gun position replaced by the antenna for the AN/APN-122 Doppler Navigation Set), better crew accommodation and an improved bow to reduce spray during takeoff and landing.

Built as a successor to the PBM Mariner, it had better engines, improved hull form, and a more conventional tail. The XP5M Marlin prototypes were based on the last PBM-5 Mariners, the company designation being Model 237. the type was heavily improved again leading to the P5M-2 (Model 237B), which was redesignated SP-5B. A number of P5M-1 models were also used for training, designated TP-5A (after 1962).


  • XP5M
  • P5M-1
  • P5M-1G
  • P5M-1S
  • P5M-1T
  • P5M-2
  • P5M-2S
  • P5M-2G
  • P5M-3 (Model 313)
  • P-5A
  • SP-5A
  • TP-5A
  • P-5B
  • SP-5B


The last flying boat operations of the United States Navy were Market Time patrols of VP-40. Maritime surveillance began in February 1965 to locate small craft transporting supplies from North Vietnam to Viet Cong units in South Vietnam. VP-40 operated from seaplane tenders and patrolled off the Mekong delta between Phú Qu?c and Vung Tau. The last U.S. Navy P5M, redesignated as an SP-5B, was flown to NAS Patuxent River, Maryland on 12 July 1968 for interim storage pending construction of display area at the Smithsonian Institution in Washington, DC. As a display area at Smithsonian did not materialize, the aircraft was later relocated to the National Naval Aviation Museum at NAS Pensacola, Florida where it is currently on display.

U.S. Coast Guard

Seven P5M-1Gs and four P5M-2Gs were built for the United States Coast Guard for air-sea rescue service, but the service found the planes difficult to maintain and surplus to requirements. They were subsequently transferred to the U.S. Navy, which redesignated them as TP-5As and used them as training aircraft, since they had no provision for armament.

French Navy

The French Navy took delivery of ten former U.S. Navy Marlins between 1957 and 1959 to replace Short Sunderlands in maritime patrol service, based out of Dakar, Senegal in West Africa. They were returned five years later.

Role Patrol aircraft
Manufacturer Glenn L. Martin Company
First flight 30 May 1948
Introduction 1952
Retired 1967
Status Retired
Primary users United States Navy
United States Coast Guard
French Navy
Number built 285
Developed from Martin PBM Mariner

General characteristics

  • Crew: 11
  • Length: 100 ft 7 in (30.7 m)
  • Wingspan: 117 ft 2 in (35.7 m)
  • Height: 32 ft 9 in (10.0 m)
  • Wing area: 1,406 ft² (130.1 m²)
  • Empty weight: 50,485 lb (22,900 kg)
  • Loaded weight: 72,600 lb (33,000 kg)
  • Max. takeoff weight: 85,000 lb (38,600 kg)
  • Powerplant: 2 × Wright R-3350-32WA radial engines, 3,450 hp (2,570 kW) each


  • Maximum speed: 218 kn (404 km/h, 251 mph)
  • Cruise speed: 130 kn (242 km/h, 150 mph)
  • Range: 1,783 nmi (3,300 km, 2,050 mi)
  • Service ceiling: 24,000 ft (7,300 m)
  • Rate of climb: 1,200 ft/min (6.1 m/s)
  • Wing loading: 60.5 lb/ft² (287 kg/m²)
  • Power/mass: 0.081 hp/lb (0.13 kW/kg)


  • 4 × 2,160 lb (980 kg) torpedoes or
  • 4 × 2,000 lb (907 kg) mines or bombs or
  • 8 × 1,000 lb (454 kg) mines or
  • 16 × 500 lb (227 kg) bombs or
  • 16 × 330 lb (150 kg) depth charges or
  • 1 × Mk.90 "Betty" nuclear depth charge


  • AN/APS-44 radar (later replaced by AN/APS-80 radar)

End notes