The Martin P5M Marlin (P-5 Marlin after 1962), built by the Glenn L. Martin Company of

Middle River, Maryland Middle River is an unincorporated community and census-designated place in Baltimore County, Maryland, United States. The population was 33,203 at the 2020 census. A Middle River Train Station first appeared on the 1877 G.M. Hopkins & Co Baltimore ...

, was a twin piston-engined

flying boat A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fuselag ...

that entered service in 1951, and served into the late 1960s with the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

performing naval patrols. It also served with the

United States Coast Guard The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, m ...

and the

French Navy The French Navy (french: Marine nationale, lit=National Navy), informally , is the maritime arm of the French Armed Forces and one of the five military service branches of France. It is among the largest and most powerful naval forces in t ...

. 285 were produced.

Development

Built as a successor to the

PBM Mariner The Martin PBM Mariner was an American patrol bomber flying boat of World War II and the early Cold War era. It was designed to complement the Consolidated PBY Catalina and PB2Y Coronado in service. A total of 1,366 PBMs were built, with the fi ...

, it had better engines, an improved hull, and a single vertical fin 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).

Design

The Marlin was designed as a gull-winged aircraft to place the engines and propellers high above the spray. Power was provided by two

Wright R-3350 The Wright R-3350 Duplex-Cyclone is an American twin-row, supercharged, air-cooled, radial aircraft engine with 18 cylinders displacing nearly . Power ranged from 2,200 to over 3,700 hp (1,640 to 2,760 kW), depending on the model. ...

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ...

s. 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 cannon in each, as well as a dorsal turret with two 0.5 in (12.7 mm)

M2 Browning machine gun The M2 machine gun or Browning .50 caliber machine gun (informally, "Ma Deuce") is a heavy machine gun that was designed towards the end of World War I by John Browning. Its design is similar to Browning's earlier M1919 Browning machine gun, ...

s. The cockpit area was the same as the Mariner's. It first flew on 30 May 1948.Swanborough and Bowers 1976, p.323. 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 A radome (a portmanteau of radar and dome) is a structural, weatherproof enclosure that protects a radar antenna. The radome is constructed of material transparent to radio waves. Radomes protect the antenna from weather and conceal antenna e ...

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 A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs from the standard configuration in which the tailplane is ...

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.

Operational history

U.S. Navy

The last flying boat operations of the United States Navy were Market Time patrols of VP-40.An Illustrated Guide to The Air War Over Vietnam by Nalty, Bernard C., Watson, George M., and Neufeld, Jacob: Arco Publishing (1981) pp.106–107. Maritime surveillance patrols began in February 1965 to locate small craft transporting supplies from North Vietnam to

Viet Cong , , war = the Vietnam War , image = FNL Flag.svg , caption = The flag of the Viet Cong, adopted in 1960, is a variation on the flag of North Vietnam. Sometimes the lower stripe was green. , active ...

units in South Vietnam.The Naval Air War in Vietnam by Mersky, Peter B, and Polmar, Norman: Nautical and Aviation Publishing Company of America (1981) p.30. VP-40 operated from seaplane tenders and patrolled off the

Mekong The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annual ...

delta between Phú Quốc and Vung Tau.The Vietnam War by Bonds, Ray: Salamander Books (1979) p.132. The last U.S. Navy P5M, redesignated as 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 The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Found ...

in Washington, DC. As a display area at Smithsonian did not materialize, the aircraft was later relocated to the

National Naval Aviation Museum The National Naval Aviation Museum, formerly known as the National Museum of Naval Aviation and the Naval Aviation Museum, is a military and aerospace museum located at Naval Air Station Pensacola, Florida. Founded in 1962 and moved to its cur ...

at NAS Pensacola, Florida where it is currently on display.Flecknoe, Harold J. "Progress". ''United States Naval Institute Proceedings'', October 1968. The final Marlin flight was carried out by VP-40, to

San Diego Bay San Diego Bay is a natural harbor and deepwater port located in San Diego County, California near the U.S.–Mexico border. The bay, which is long and wide, is the third largest of the three large, protected natural bays on California's of ...

on 6 November 1967.

U.S. Coast Guard

Seven P5M-1Gs and four P5M-2Gs were built for the

for

air-sea rescue Air-sea rescue (ASR or A/SR, also known as sea-air rescue), and aeronautical and maritime search and rescue (AMSAR) by the ICAO and IMO, is the coordinated search and rescue (SAR) of the survivors of emergency water landings as well as people ...

service, but they 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

took delivery of ten former U.S. Navy Marlins between 1957 and 1959 to replace

Short Sunderland The Short S.25 Sunderland is a British flying boat patrol bomber, developed and constructed by Short Brothers for the Royal Air Force (RAF). The aircraft took its service name from the town (latterly, city) and port of Sunderland in North Ea ...

s in maritime patrol service, based in

Dakar Dakar ( ; ; wo, Ndakaaru) (from daqaar ''tamarind''), is the capital and largest city of Senegal. The city of Dakar proper has a population of 1,030,594, whereas the population of the Dakar metropolitan area is estimated at 3.94 million in 2 ...

Senegal Senegal,; Wolof: ''Senegaal''; Pulaar: 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Senegaali); Arabic: السنغال ''As-Sinighal'') officially the Republic of Senegal,; Wolof: ''Réewum Senegaal''; Pulaar : 𞤈𞤫𞤲𞤣𞤢𞥄𞤲𞤣𞤭 ...

in West Africa. They were returned in 1964.

Variants

Company designations

;M-237: Company designation for P5M-1 ;M-237B: Company designation for P5M-2 ;M-270: XP5M-1 prototype converted with a revised hull. ;M-290: Company designation for P5M-3 which was completely revised into the unbuilt four-engine P7M SubMaster

Pre-1962 designations

;XP5M-1 :Prototype converted from a

with modified hull and tail.Andrade 1979 p207 ;P5M-1 :Production model for the

, 160 built, later redesignated P-5A. ;P5M-1G :Modified P5M-1 for the

, seven conversions, later returned to the Navy as P5M-1T. ;P5M-1S :Modified P5M-1 with upgraded electronic and anti-submarine equipment, eighty conversions, later redesignated SP-5A. ;P5M-1T :Seven former USCG P5M-1Gs returned to Navy as crew trainers and one former P5M-1, later redesignated TP-5A. ;P5M-2 :Updated model, 108 built for the U.S. Navy and 12 built for the French Navy. The P5M-2 featured a T-tail in lieu of the low mounted horizontal stabilizer used on the P5M-1s. United States aircraft were later redesignated P-5B. ;P5M-2S :Most P5M-2s were modified with upgraded electronic and anti-submarine equipment, later redesignated SP-5B. ;P5M-2G :Four P5M-2s built for the USCG, later transferred to U.S. Navy as P5M-2s. ;P5M-3 :Completely revised as four-engine M-313 P7M-1 SubMaster. Mockup built in 1956 but lost to Lockheed P-3 Orion.

Post-1962 designations

;P-5A :P5M-1 redesignated in 1962.Andrade 1979 p157 ;SP-5A :P5M-1S redesignated in 1962. ;TP-5A :P5M-1T redesignated in 1962. ;P-5B :P5M-2 redesignated in 1962. ;SP-5B :P5M-2S redesignated in 1962.

Operators

; France *

; United States *

Survivors

One SP-5B is located at the

Naval Air Station Pensacola Naval Air Station Pensacola or NAS Pensacola (formerly NAS/KNAS until changed circa 1970 to allow Nassau International Airport, now Lynden Pindling International Airport, to have IATA code NAS), "The Cradle of Naval Aviation", is a United State ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...

. This aircraft, BuNo ''135533'', is believed to be the last remaining example of the Marlin. It is now displayed inside the new hangar (as of the spring of 2010) and much of the exterior has been restored. The restoration is being financed by the museum and the Mariner/Marlin Association."P5M Marlin/135533."
''National Naval Aviation Museum.'' Retrieved: 21 February 2015.

Specifications (P5M-2)

References

;Notes ;Bibliography *Andrade, John, ''U.S.Military Aircraft Designations and Serials since 1909'', Midland Counties Publications, 1979, . *Barth, Bruce D., "The Martin P5M 'Marlin'". Pacific Aero Press, 1994. *Roberts, Michael D. ''Dictionary of American Naval Aviation Squadrons: Volume 2 The History of VP, VPB, VP(HL) and VP(AM) Squadrons''. Washington DC: Naval Historical Centre, 2000. *Swanborough, Gordon and Bowers, Peter M. ''United States Navy Aircraft since 1911''. London:Putnam, Second edition 1976. . *The ''

Illustrated Encyclopedia of Aircraft The ''Illustrated Encyclopedia of Aircraft'' was a weekly partwork magazine by Aerospace Publishing (an imprint of Orbis Publishing) which was published in the United Kingdom (and sold in other countries too) during the early 1980s. The magazi ...

'' (Part Work 1982–1985), 1985, Orbis Publishing, Page 2420

External links

Naval Aviation Museum – Aircraft – 'P5M-2S (SP-5B) Marlin'
{{DEFAULTSORT:Martin P5m Marlin P5M Martin PM5 Marlin Flying boats High-wing aircraft Gull-wing aircraft T-tail aircraft Aircraft first flown in 1948 Twin piston-engined tractor aircraft