Prior to her acquisition by Canada, Moresby served as the offshore supply vessel Joyce Tide, built by Allied Shipbuilders of Vancouver, British Columbia.

Joyce Tide was acquired by the Canadian Forces for conversion to a minesweeper and as a training ship for naval reservists.

With the entry into service of the Kingston-class coastal defence vessels, Moresby was sold to commercial interests, returning to her previous career.

[3] The vessel was purchased in 1988 by Maritime Command (MARCOM) of the Canadian Forces and converted into a minesweeping auxiliary.

[3] The ship was laid down as Lady Joyce by Allied Shipbuilders Ltd. of Vancouver with the yard number 180 and launched on 11 November 1972.

[2] As part of the plan for the Naval Reserve to take over minesweeping and coastal operations, MARCOM began its effort to provide ships for training.