Assigned to the Naval Research Laboratory (NRL), Washington, D.C., "Aquamarine" assisted in experimental work, chiefly underwater sound. Although most of her experiments were conducted on the Potomac River and Chesapeake Bay, she also operated off New London, Connecticut, from 16 October to 4 November 1943, and off the Florida coast and in the Bahamas from 24 January 1944 to 18 April 1945. Most work was in acoustics with limited work with radar, mines, and underwater communications. During 1945 and 1946 "Aquamarine" had additional duty as special tender to the presidential yachts and .