“The Sea Dart began as Convair‘s entry to a 1948 U.S. Navy contest for a supersonic interceptor aircraft. There was at the time much skepticism about operating supersonic aircraft from aircraft carrier decks, which explains why the U.S. Navy ordered so many subsonic fighters at that time. The worry had some foundation, since many supersonic designs of the time required long takeoff rolls and had high approach speeds, and were not very stable or easy to control – all factors that were troublesome on a carrier.
Convair’s proposal gained an order for two prototypes in late 1951. Twelve production aircraft were ordered before a prototype had even flown. No armament was ever fitted to any Sea Dart built, but the plan was to arm the production aircraft with four 20 mm (.79 in) cannon and a battery of folding-fin unguided rockets. Four of this order were redesignated as service test vehicles, and an additional eight production aircraft were soon ordered as well.”
Source: Wiki.; Seaplanes Of the World, Bill Yenne, 1997