Naval Fighters Number Thirty-Three XTBU-1 & TBY-2 Sea Wolf;

In 1939 with war on the horizon, the U.S. Navy's Bureau of Aeronautics sent the aviation industry a request for proposal for a new torpedo-bomber (VTB). The competition was won by Grumman with its XTBF-1 proposal. Known as the Avenger, two XTBF-1 prototypes were ordered in the spring of 1940. Vought also had a promising proposal and was awarded a contract for one XTBU-1 prototype.