From 1776 to 1790 she was a whaler in the Greenland whale fishery, though she also spent time trading generally, and as a transport.

In 1791 she commenced a voyage to the southern whale fishery but received damage en route and was condemned at the River Plate.

[1] Captain William Ramsey sailed on 22 July 1791, bound for the Southern Whale Fishery.

[3] Mentor was reported to have put into Buenos Aires or Montevideo on 20 December.

[4] LR continued to carry Mentor for some years thereafter,[5] but with data unchanged since 1791.