Hancock was built at Newburyport, Massachusetts, and placed under command of Captain John Manley 17 April 1776. After a long delay in fitting out and manning, she departed Boston, Massachusetts in company with Continental frigate Boston, 21 May 1777. On 29 May they captured a small brig loaded with cordage and duck. The next day they encountered a convoy of transports escorted by British 64-gun ship Somerset which set sail to close Hancock. Manley was saved by clever and well-timed action of Boston, which forced Somerset to give up the chase by taking on the transports.