SeaMaster and Sea Dart — a pity

SeaMaster and Sea Dart — a pity they never came to be

The 1950s were a time of transition in military technology with aircraft moving from propellers to turbojets, submarines moving from diesel engines to nuclear propulsion and missiles challenging aircraft as the most strategic of weapon systems, and the Kalashnikov AK-47 setting a new paradigm for the standard infantry weapon having semi-automatic or automatic fire.

So — where was the flying boat in all of this? After all, flying boats had range for reconnaissance and loiter time for antisubmarine patrolling. Radar was still primitive and there was no such thing as satellite reconnaissance. Cold War Land based strategic bombers existed but had no hope of fighter escorts, carrier aircraft were capable of only limited strategic nuclear delivery and turbojet aircraft were just coming to the forefront as attack aircraft, and Polaris equipped submarines were just undergoing development.

The U.S. Navy (USN) was in a jam. The U.S. Air Force (USAF) was vying to be the sole authority in strategic weapons delivery for the U.S. armed services — to the great detriment of the USN. This fight must have seemed like déjà vu to historians with regard to the Mitchell vs. Moffett battles in the 19020s.

Along with the Forrestal class aircraft carriers, and Polaris missile submarines, the USN chose to pursue the concept of the Seaplane Striking Force (SSF) in the 1950s for strategic nuclear strike capability as well as minelaying missions — where aircraft would operate from the water with only ships for logistical support, even submarines for refueling duties. The Imperial Japanese Navy (IJN) had introduced the beginnings of the concept in WW II with very long ranged flying boats as well as float equipped fighter aircraft — albeit these were intended to operate from remote Pacific isles. Early in the war however, during March 1942, the IJN launched “Operation K” as a special mission when two Kawanishi H8K “Emily” flying boats were refueled by submarine on an over 4000 mile (6400km) flight to again bomb Pearl Harbor. This mission profile may have impressed the USN. Whether Operation K did or did not impress, the USN selected Martin to develop the P6M SeaMaster turbojet powered flying boat and Convair to design the seaborne turbojet powered fighter known as the F2Y Sea Dart*. Together these aircraft, support aircraft and support ships would constitute a strategic force that could be deployed near almost any enemy shore or even deep within enemy territory for weeks to months per deployment cycle. The SSF, the Seaplane Striking Force, would be the naval strategy for nuclear deterrence as well as minelaying to deny seaborne logistical support.

That was the theory.

So what happened to the SSF and especially the SeaMaster?

Martin worked for nearly a decade and the USN spent $445 million though recovering $84M so the net cost was $361M. What does that mean? In 2009 dollars that amount equals $2.7 billion dollars! That was quite an undertaking for the USN and in the end only 16 aircraft were produced (2 were lost in accidents) and none saw service. The nearly decade long design and testing period saw the advent of the nuclear powered aircraft carrier with more capable aircraft as well as the ballistic missile submarines armed with IRBMs (Intermediate Range Ballistic Missiles). The P6M simply lost out to better technology but had also lost due to problems related to aircraft shudder and adverse fuselage heating aft the inner engines.

But the P6M was also the top of the evolutionary ladder with regard to the long range and fast military flying boat with its ability to fly at nearly the speed of sound (Mach .96), a range of 2000 miles (3200km) and an operational altitude of 40,000 feet (12,000m). This seaplane was truly remarkable and has no peer or even a close second. Yet none exist, none are in storage and there are no derelict wrecks to be found. This is very unlike the fates of the Sea Darts where each of the existing aircraft found homes at museums. When the SeaMaster program was cancelled — recall the USN had spent a huge sum over a ten year span and it is rare for a bureaucracy to admit failure — all the aircraft were immediately stripped of their engines and instruments, then broken up for scrap.

One could say that the evidence was “disappeared”, if one were cynical.

Or one could say that “it was best for the ledger book”, if business minded.

But the failure of the P6M to get into service was a failure of daring greatly. Think of it, a seaplane that flew as fast as a Boeing B-52 Stratofortress does today and one that flew faster and a lower altitude than the SeaMaster’s USAF contemporary, the Boeing B-47 Stratojet, but not limited to a very few airfields of the world. A seaplane that could operate from nearly anywhere has the ability to strike from unexpected directions forcing potential enemies to spend exponentially more on defense, thus limiting their offensive capabilities. The Whitcomb area rule (transonic area rule) was known in the mid 1950s but does not seem to have been applied to the SeaMaster design. But what if it had been? Would the aircraft shudder have disappeared? Would the range had been extended? Materials that began to emerge in the 1960s may have eliminated the excessive heating to the aft fuselage skin, as well. The P6M could have been an aircraft that could not have been reckoned with even though the Sea Dart design lost favor.  SSF squadrons might have been equal partners with the aircraft carrier task forces and Strategic Air Command bombers. Sadly, this would be the final aircraft design to fly for Martin.

It’s a shame that none of SeaMasters found their way to a museum — a very sad shame as the P6M SeaMaster is an unequaled historical aircraft. Although in storage there are some bits saved at the Glenn L Martin Maryland Aviation Museum in Baltimore — a pair of tail assemblies (possibly only the vertical segments) as well as a pair of wingtip floats and an aft  fuselage section.

The material for this post came from:

• Attack from the Sea: a history of the U.S. Navy’s Seaplane Striking Force — by William T. Trimble, published in 2005 with the ISBN of 1-59114-878-2
• The Second Attack on Pearl Harbor: Operation K and other Japanese attempts to bomb America in WW II — by Steve Horn, published in 2005 with the ISBN 0f 1-59114-388-8
• Glenn L Martin Maryland Aviation Museum web site

* For a post on the Sea Dart as well as photos please type “Sea Dart” into the search window and select ENTER.