HMCS Preserver was a depot ship of the Coastal Forces of the Royal Canadian Navy during World War II.

Renamed Cayo Blanco and then Petronap the vessel caught fire and wrecked at San Lorenzo Island near Callao on 20 April 1963.

[1][4] The ship was commissioned on 11 July 1942 at Sorel and sailed for Halifax, Nova Scotia on 4 August, escorting a Quebec-Sydney convoy en route.

Botwood had been planned as a new Royal Canadian Navy base and Preserver and the Fairmiles were sent there to protect the transports unloading aviation fuel at Lewisporte that was destined for the airfield at Gander.

At the end of July 1943, Preserver and the Fairmiles relocated to Red Bay, returning to St. John's in November.

[4] Due to strategic changes in the Atlantic theatre, Botwood was abandoned as a base and Preserver and the Fairmiles became the only Royal Canadian Navy vessels ever to deploy there.

The Miramar Ship Index states the vessel was sold into commercial service to Agencia Nacional de Vapores Jose Poblete Vidal in 1960 and renamed Cayo Blanco and registered in Panama.