THE P6M-2 “SEAMASTER”

The draw-down of US armed forces after World War II was accompanied by a shift in military strategy.  The advent of the atomic bomb captivated military planners even to the extreme of entertaining the elimination of conventional Navy, Marine Corps, and Army forces.  Faced with these severe cutbacks, the Navy scrambled to get a foothold in the atomic weapons game.  But delivering such weapons in that day required bombers too large to deploy from existing aircraft carriers.  So, the Navy Bureau of Aeronautics established the “Seaplane Striking Force” that envisioned a fleet of full-sized, jet-powered strategic bombers that could land and take-off from the water’s surface.  This board released specifications in April 1951 for a plane that was to carry 30,000 pounds of bombs or sea mines, have a 1500-mile unrefueled range, and be capable of speeds of Mach 0.9.  Publicly advertised as a mine-layer/reconnaissance plane, both Convair and Martin bid on the project.  The Martin XP6M-1 “SeaMaster” design was chosen.  Two prototypes and six evaluation aircraft were authorized, with the promise of 24 operational planes if successful.

Martin responded with a 134-foot, swept-wing bomber with four jet engines, two each at the roots of an overhead wing.  Its boat-shaped hull and wingtip floats assured stability during taxi and take-off.  Four men would be required to crew the design, whose only defensive armament was a remote control 20mm cannon turret in the tail.  Early tests showed the engines had to be angled slightly outward to prevent scorching the fuselage on afterburner.

On this date a YP6M-1 “SeaMaster” prototype made her first flight.  However, this same plane crashed into the Chesapeake Bay on 7 December killing all four Navy crewmen aboard.  A second prototype, now fitted with ejection seats, also crashed on 9 November the following year.  Despite these failures the Navy proceeded with development, at the same time converting two LSDs, two seaplane tenders, and the submarine USS GUAVINA (AGSS-362) for use as “SeaMaster” support vessels.  A home base for the envisioned squadrons was built at NAS Harvey Point, North Carolina.  All six evaluation models flew successfully, and the first production P6M-2 was delivered in 1959.

But only six months before deployment of the first squadron, the “SeaMaster” program was suddenly canceled on 21 August 1959.  The Polaris missile submarine had eclipsed the long-range strategic bomber as an atomic weapons delivery platform.  Today only a tail assembly from one P6M-2 remains in the Glenn L. Martin Maryland Aviation museum in Baltimore.  In fact, the wingtip floats from the last P6M were reportedly used by a Martin employee to build a catamaran.

Watch for more “Today in Naval History”  21 JUL 26

CAPT James Bloom, Ret.

Department of the Navy, Deputy Chief of Naval Operations (Air Warfare).  United States Naval Aviation 1910-1980.  Washington, DC: GPO, 1981, pp. 209-10.

Department of the Navy, Naval History Division.  Dictionary of American Naval Fighting Ships, Vol 3 “G-K”. Washington, DC: GPO, 1977, pp. 179-80.

Jackson, Robert.  Infamous Aircraft:  Dangerous Designs and their Vices.  Barnsley, England: Pen & Sword, 2005, pp. 118-19.

“The Martin SeaMaster & Convair Sea Dart.”  http://www.vectorsite.net/avcmast.html, 19 March 2006.

“P6M SeaMaster.”  Wikipedia on-line encyclopedia, http://em.wikipedia.org/wiki/P6M_SeaMaster, 19 March 2006.

Shettle, M.L., Jr.  United States Naval Air Stations of World War II  Vol 1  Eastern States.  Bowersville, GA: Schaertel Pub Co., 1995, pp. 98-99, 145.

ADDITIONAL NOTES:  The original design called for the engines to be of ram-jet type, though the technology of this advanced design had not yet been perfected.  A three-fold cost overrun from the original bid also contributed to the program’s demise.  The P6M was the last aircraft built by the Martin Corporation.

NAAS Harvey Point was built during WWII as a base for the Martin PBM seaplane.  Today it remains in Department of Defense hands as the Harvey Point Defense Testing Facility.  Much of the work done at this facility today is classified, and the base is not shown on civilian aviation charts.

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