query: Who builds ships for the US Navy?
passage: Huntington Ingalls Industries
HII is the sole designer, builder, and refueler of nuclear-powered aircraft carriers in the United States. It is one of two nuclear-powered submarine builders (the other being General Dynamics Electric Boat). 70% of the current, active U.S. Navy surface fleet has been built by HII's former units.[7]
passage: Liberty ship
In 2011, the United States Postal Service issued a postage stamp featuring the Liberty ship as part of a set on the U.S. Merchant Marine.
Liberty ships were built at eighteen shipyards located along the U.S. Atlantic, Pacific and Gulf coasts:There are four surviving Liberty Ships.