Premise: USS "PC-1168" was a "PC-461"-class submarine chaser built for the United States Navy during World War II. "PC-1168" is notable for being the ship on which the film "You're in the Navy Now", which starred Gary Cooper, was filmed in 1950. The ship was later transferred to the Republic of China Navy, serving from 1954 to 1970 as ROCS "Ching Kiang" (PC-116).
Hypothesis: The USA has never built submarines.