From the late 1940s to the end of the ’50s, the United States Navy sought to define its role in the new Atomic Age. The Navy’s first attempt at a strategic nuclear deterrent, 1949′s super-carrier USS United States and its whiz-bang air wing, was sunk during heated battles between dissident admirals and Defense Secretary Louis Johnson. The Navy next turned to its oldest form of aircraft: the seaplane.
The Seaplane Strike Force was a visionary concept built upon a new generation of jets and turboprops that could be deployed and supported by tenders and even subs in far-forward waters away from observation or attack. Taking the lessons learned during World War II and Korea, along with new research into hydrodynamics and aerodynamics, Martin and Convair created some of the coolest flying machines ever: the P6M SeaMaster jet flying boat, the F2Y Sea Dart supersonic seaplane fighter and the R5Y Tradewind turboprop flying boat.
We’ll cover each plane in depth in other articles; for now, we’ll start with the Martin P6M.
Glenn L. Martin, the man and the company, had been involved in seaplanes since the dawn of aviation. In the 1930s, Martin Aircraft designed and built the first trans-Pacific flying boats, the M-130 China Clippers, for Pan American Airways; in the ’40s, Martin built the PBM Mariner patrol bomber, its successor the P5M Marlin and the huge JRM Mars transport for the Navy. Martin was eager to apply all his company had learned on an Atomic Age seaplane.
Specified in 1951, SeaMaster was originally intended for high-speed aerial mine-laying, with the Soviet Baltic, Black Sea and Far East ports in mind. As nuclear weapons became smaller and more powerful, the plane acquired the strategic bombing role. The seaplane’s revolutionary rotary bomb bay was easily adapted for a variety of weapons, including an air-refueling “buddy pack.”
The first XP6M prototype rolled out in secret in 1954 and revealed two serious issues: the afterburners scorched the aft fuselage and tail on takeoff, and flaws in the aircraft controls killed the first test crew in a crash. The engines long proved an anchor for the SeaMaster’s performance. Originally slated to have ultra-zoomy Curtiss-Wright turbo-ramjets, the Allison turbojets initially available simply weren’t up to the task.
The Navy persevered with its strategic programs during the ’50s. Nuclear propulsion turned out well, carrier-based aircraft could now carry the Bomb, and of all things (though very few were allowed to know it) the Polaris sub-launched ballistic-missile program was yielding dramatic results. The Navy traded 12 planes of the original 24-plane order for a continuation of the SeaMaster program, and by 1959 the P6M-2 was ready for showtime.
It was an amazing machine. Weighing in at over 120,000 pounds fully loaded, with its righteous new Westinghouse engines the SeaMaster could take off near a tender in sea states up to 3 and carry its 30,000-pound weapons load 2,000 miles at 600 miles per hour. Test pilots reported exceeding Mach 1 in shallow dives from 20,000 feet. The big aircraft was built so robustly (up to one-half-inch-thick aluminum alloy at the wing roots) that it could conduct high-subsonic on-the-deck attacks in all sorts of weather. Its four-man crew, armed with state-of-the-art radar, inertial navigation and bombing systems, could mine a harbor or vaporize a town from any body of water on earth.
To support such a big bomber, a new kind of seaplane tender was needed. USS Albemarle had her repair deck replaced at great expense with a huge powered sea sled designed to slide under the seaplane and draw it up into the ship for servicing. Plans were even made for modifying LSDs into SeaMaster tenders.
It was also a really expensive weapons project — over $400 million in Eisenhower dollars — and the original 24-plane buy was whittled away to eight by the time the P6M-2s were ready for service in 1959. The problem of delivering sea mines at 500 miles per hour still wasn’t resolved. Admiral Rickover couldn’t stand the SeaMaster project, and with the success of the Polaris SLBM program the Navy abruptly dumped the big seabird. Martin soon abandoned aircraft altogether to focus on missiles, and Albemarle was later converted into a helicopter-repair base for the brown-water Navy in Vietnam.
And the SeaMaster? Surely such a magnificent aircraft is enshrined in a museum somewhere? No:
The “flying tails” and two rear fuselage sections were sent to Navy test facilities, while two sets of wing floats were used by a Martin supervisor to build a catamaran. Two tails, one fuselage section and wing floats now belong to the Glenn L. Martin Maryland Aviation Museum.
Everything else — all eight seaplanes — was scrapped before JFK took office.