Sir William Douglas was a slave ship in the triangular trade in enslaved people, acquired by British interests in 1801.

[5] 1st voyage transporting enslaved people (1801–1802): Captain William Hannay acquired a letter of marque on 22 August 1801.

[6] In February 1802, Lloyd's List reported that Sir William Douglas, Shaw, master, had arrived at Bonny.

[6] Lloyd's List reported in November that William Douglas, Shaw, master, was off Barbados, bound for Charleston.

[7] In January 1804 Lloyd's List reported that Sir William Douglas had been taken on her way to London and that her captain had arrived at Bordeaux.