P5M Marlin

US Coast Guard Martin P5M-2G Marlin

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

Built as evolutionary successor to the PBM Mariner, it had better engines, improved hull form, and more conventional tail. The XP5M Marlin prototypes were based on the last PBM-5 Mariners, the company designation being Model 237. It would be 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).

The Marlin was designed as a gull-winged aircraft to lift 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; this gave the aircraft a longer base of flotation and reduced "porpoising" over waves, a Martin innovation.

The prototype had nose and tail turrets with twin 20 mm cannon 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 May 1948.

The first of 167 production P5M-1 aircraft was produced in 1949. 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.

P5M-2 / SP-5B

The P5M-1 was followed by 116 P5M-2 planes. These had a T-tail to put the tail surfaces out of the spray, a AN/ASQ-8 MAD boom at the rear of the tail-tip, no tail guns, better crew accommodation and an improved bow to reduce spray during takeoff and landing.

Versions

• XP5M-1 - Prototype. 1 built.
• P5M-1 (P-5A) - This was the first production model US Navy. 160 built.
• P5M-1S (SP-5A) - Redesignation of the P5M-1, with upgraded electronic and anti-submarine equipment.
• P5M-2 (P-5B) - This was the second production model for the US Navy. 115 built.
• P5M-1G - Redesignation of seven aircraft used by the US Coast Guard.
• P5M-1T (TP-5A) - Redesignation of former USCG P5M-1Gs, used by the US Navy as crew trainers.
• P5M-2G - Redesignation of four aircraft used by the US Coast Guard.
• P5M-2S (SP-5B) - Redesignation of most P5M-2s after being fitted with advanced avionics, and anti-submarine detection equipment.
• SP-5 - SIGINT/ELINT version used over Viet-Nam.

Operators

US 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 given to the Navy, which used them as trainers since they had no provision for armament.

French Navy

The French Navy took delivery of ten ex-USN Marlins in 1959 to replace Short Sunderlands in maritime patrol service, based out of Dakar, Senegal in West Africa. They were returned five years later.

Surviors

One P-5 is at the US Naval Aviation Museum in Pensacola, Florida.

Related content

Related development
PBM Mariner - P7M Submaster Comparable aircraft
Beriev Be-12 - Short Sunderland Designation sequence

• Martin
  • Model 162 - Model 237 - Model 313
• 1922-1962 Navy :
  • PM - P2M - P3M - P4M - P5M - P6M - P7M
• Post-1962 Joint Service:
  • Patrol: ^{P-1 Skipped} - P-2 - P-3 - P-4 - P-5 - ^Reserved - P-7 - P-8
  • ASW: S-2 - S-3, SP-5, SH-2 - SH-34 - SH-60

Related lists
List of military aircraft of the United States - List of flying boats and seaplanes