Lady Forrest was ordered by the Harbour and Light Department[1][2] for use by the newly created Fremantle Harbour Trust, replacing the Rottnest-Fremantle pilot Atlantic, which became a fishing boat,[3] and an insufficient earlier pilot, Pelican, built in 1900.

[6] One of its earliest captains was Macfarlane during which it was berthed at Victoria Quay,[7] it was overhauled almost every third month at North Wharf.

[8] Immigrants arriving in Western Australia were greeted by the State Labour Bureau headed by A. O. Neville aboard the Lady Forrest.

[9] In August 1942 it had the brass conning tower installed from the Dutch submarine HNLMS K VIII which had been decommissioned and was later scuttled in Cockburn Sound.

[10][5] When HMAS Dalgoma broke free of its anchors and collided with the coal hulk Samuel Plimsoll resulting in its sinking in 1945[11] the Lady Forrest took depth soundings to find deeper water.