In 1948, the U.S. Navy created a contest for engineering companies to develop a supersonic interceptor seaplane, and it did this for a good reason, too. Aircraft carriers at that time could not accommodate the long takeoff and landing distances required by land-based supersonic jets, so the Navy figured it’d try using the ocean as the runway. The most prolific entry evaluated by the Navy, the F2Y Sea Dart, came from the Convair division of General Dynamics based at Lindbergh Field in San Diego, California.
Convair’s proposal resulted in an order from the Navy of two prototypes in late 1951. The long-term plan was to arm the production aircraft with four 20mm Colt Mk12 cannons and a battery of folding-fin unguided rockets, but none of these were installed on the prototypes.