Martin SP-5B Marlin
To replace the aging PBM Mariner, Martin began work on the P5M Marlin in 1946. The first XP5M-1 was essentially an upgraded Mariner, with a new fuselage. To keep the engines clear of the spray, the Mariner's gull wing was kept, though the floats were made more hydrodynamic; to improve the Marlin's performance on the water, "hydroflaps" were introduced. In the air, the hydroflaps doubled as speedbrakes, while in the water, they were used to improve the Marlin's turning circle in narrow harbors. The P5M-1 went into service in 1952. Because it was intended more as an antisubmarine warfare/rescue aircraft, the three turrets of the XP5M-1 were deleted on production aircraft.
While the P5M-1 was adequate and well-liked by its crews, Martin wanted to improve the design. The P5M-2 was nearly a new aircraft, with a redesigned forward fuselage to cut down on water spray even more, and a more aerodynamic T-tail, which also allowed for the inclusion of a Magnetic Anomaly Detector (MAD) boom at the base of the tail. An improved radar was mounted on the nose, making the Marlin a superb antisubmarine platform. In 1962, the P5M-2 was redesignated the SP-5B.
Though Marlins were used during the Cold War to patrol the coasts of the US, their first and only combat deployment was to Vietnam in 1965 to assist in Operation Market Time. Market Time was the mostly successful attempt to stem resupply of the Viet Cong by sea from North Vietnam. The Marlin's ability to detect small targets and its long loiter time, and its ability to operate from any body of water, made it valuable for the role. Several detachments were rotated out of Cam Ranh Bay, South Vietnam, from NAS Sangley Point in the Philippines.
The Navy, however, felt that the day of the seaplane was drawing to a close, and the Marlin's role could be better done by longer-ranged, land-based P-3 Orions. The last US Navy seaplane squadron, VP-40, deactivated in 1967; the Marlin would prove to be the last aircraft produced in numbers by the Martin company before its merger with Convair. A few were operated briefly by the US Coast Guard, and ten were leased for a short time by the French Aeronavale. Of 258 P5Ms built, today only a single example survives at the National Museum of Naval Aviation in Pensacola, Florida.
This side view of a VP-48 SP-5B is another from the Lockwood collection. Not only does it show a Marlin from the side, it also shows how big of an aircraft it was (note the men in the shadow of the wing). This shows the Marlin's early 1960s scheme of white over dark blue; some Marlins carried this until the end of their careers. Mr. Lockwood took this picture at NAS Sangley Point, Philippines, in 1966. He passed away in 2015, and these pictures are presented in his honor.
Martin SP-5B Marlin
To replace the aging PBM Mariner, Martin began work on the P5M Marlin in 1946. The first XP5M-1 was essentially an upgraded Mariner, with a new fuselage. To keep the engines clear of the spray, the Mariner's gull wing was kept, though the floats were made more hydrodynamic; to improve the Marlin's performance on the water, "hydroflaps" were introduced. In the air, the hydroflaps doubled as speedbrakes, while in the water, they were used to improve the Marlin's turning circle in narrow harbors. The P5M-1 went into service in 1952. Because it was intended more as an antisubmarine warfare/rescue aircraft, the three turrets of the XP5M-1 were deleted on production aircraft.
While the P5M-1 was adequate and well-liked by its crews, Martin wanted to improve the design. The P5M-2 was nearly a new aircraft, with a redesigned forward fuselage to cut down on water spray even more, and a more aerodynamic T-tail, which also allowed for the inclusion of a Magnetic Anomaly Detector (MAD) boom at the base of the tail. An improved radar was mounted on the nose, making the Marlin a superb antisubmarine platform. In 1962, the P5M-2 was redesignated the SP-5B.
Though Marlins were used during the Cold War to patrol the coasts of the US, their first and only combat deployment was to Vietnam in 1965 to assist in Operation Market Time. Market Time was the mostly successful attempt to stem resupply of the Viet Cong by sea from North Vietnam. The Marlin's ability to detect small targets and its long loiter time, and its ability to operate from any body of water, made it valuable for the role. Several detachments were rotated out of Cam Ranh Bay, South Vietnam, from NAS Sangley Point in the Philippines.
The Navy, however, felt that the day of the seaplane was drawing to a close, and the Marlin's role could be better done by longer-ranged, land-based P-3 Orions. The last US Navy seaplane squadron, VP-40, deactivated in 1967; the Marlin would prove to be the last aircraft produced in numbers by the Martin company before its merger with Convair. A few were operated briefly by the US Coast Guard, and ten were leased for a short time by the French Aeronavale. Of 258 P5Ms built, today only a single example survives at the National Museum of Naval Aviation in Pensacola, Florida.
This side view of a VP-48 SP-5B is another from the Lockwood collection. Not only does it show a Marlin from the side, it also shows how big of an aircraft it was (note the men in the shadow of the wing). This shows the Marlin's early 1960s scheme of white over dark blue; some Marlins carried this until the end of their careers. Mr. Lockwood took this picture at NAS Sangley Point, Philippines, in 1966. He passed away in 2015, and these pictures are presented in his honor.