Harpooner returned to online records in 1782, and in 1783 became the slave ship Trelawney, which then made two complete voyages in the triangular trade in enslaved people.

[3] Lloyd's List (LL) reported on 16 March 1779 that privateer Harpooner, of London, Arnold, master, had captured two French vessels, Friendship and Achilles.

[6][a] On 9 December 1780 HMS Solebay and Portland captured two French privateers behind the Isle of Wight after a short action.

[2] 1st voyage transporting enslaved people (1783–1784): Captain William Thoburn sailed from Liverpool on 23 March 1783.

He acquired 470 captives at Cape Coast Castle, and on 1 December arrived at Kingston, Jamaica with 447, for a 9.5% mortality rate.

[11] 2nd voyage transporting enslaved people (1784–1786): Captain William Thoburn sailed from Liverpool on 2 August 1784.

Trelawney sailed from Africa on 1 September 1785 with 400 captives, and arrived at Kingston on 12 November with 350, for a 12.5% mortality rate.