The U.S. Navy had declared the submersible seaplane feasible and began funding experiments for its creation in 1964. The collection
of notes from Charles Roe Tuttle, a San Diego based engineer, explain the feasibility of this craft, as well as give calculations
to justify his stance. Tuttle’s writing “The Submarine and Airplane as an Integrated Vehicle” explains how the use of the
German Midget Submarine body would be a better fit for this craft. Tuttle worked for Convair, who acquired the contract to
develop the submersible seaplane.
In 1934 Boris Petrovich Ushakov, a student engineer at a Soviet military academy, devised a flying underwater boat - a three-engined
floatplane designed to scout out enemy ships and then ambush them. Ushakov envisaged his craft flying ahead of the target,
landing on the sea and then flooding its fuselage so that it could lie in wait beneath the surface and torpedo the ships as
they sailed past. Ushakov submitted his radical design, which included a conning tower and periscope, to senior officers in
1936. But the concept was never put into practice, being deemed too heavy to be effective.
It took another three decades before a flying sub was constructed. This was a craft built in 1962 by Donald Reid, an engineer
at the aircraft manufacturer North American Aviation. The Reid Flying Submarine (RFS-1) was a true mongrel, constructed by
Reid in his spare time using leftover parts from other aircraft and, like Ushakov's design, it was a floatplane. The craft
proved able to dive to a depth of a few meters in tests, but was so heavy it could only make short hops into the air. Though
this was at the height of the Cold War, the U.S. Navy showed little interest in Reid's machine. The difficulty with the submersible
seaplane is that aircraft must be light to minimize the power needed to get airborne, while subs need massive hulls to resist
crushing. Funding for this concept was discontinued in 1965.