Between 1799 and 1800 she made one voyage as a slave ship in the triangular trade in enslaved people.

Lord Duncan first appeared in Lloyd's Register (LR) in 1798.

[2] Captain Charles King sailed from Liverpool on 7 March 1799.

[4] Lord Duncan stopped at Sierra Leone and she arrived at Kingston, Jamaica on 2 February 1800, with 127 captives acquired at the Congo River.

[1] Although the registers carried Lord Duncan for some more years with unchanged data, her owners had sold her in the Americas after she had delivered her captives.