Here are some ships that haven't been considered.
USRC (Revenue Cutter) SCAMMEL, her first Captain was Hopley Yeaton - the first Commissioned Officer of the United States. All of the Revolutionary naval officers were technically in the Continental Navy.
USRC HARRIET LANE credited with firing the first naval shot of the Civil War.
USRC NAUGATUCK, also known as E. A. STEVENS, was a gun battery that could partially submerge for protection. She took part in the battle between USS MONITOR and CSS VIRGINIA.
USRC RUSH, seal poachers would often "Come early and avoid the Rush."
USRC HUDSON a 95' steam tug noted for towing the disabled USS WINSLOW out of harms way in Cuba during the Spanish American War.
CGCs EASTWIND and SOUTHWIND captured the Nazi weather and supply vessel EXTERNSTEINE off the coast of Greenland after a brief fire-fight on October 14, 1944. There were no casualties. EXTERNSTEINE was the only enemy surface vessel captured at sea by U.S. naval forces during the war.
USCGCs STORIS, SPAR, & BRAMBLE worked their way up around Alaska and Canada in 1957. SPAR & BRAMBLE continued to the east coast; STORIS returned to west to Alaska. SPAR later became the first US Vessel to circumnavigate North America.
USCGC POLAR SEA became the first US surface vessel to reach the North Pole on August 22, 1994.