DPST (Drydock Period for Special Survey)

DPST is the drydocking carried out as part of a ship’s special survey, the class renewal survey held every five years. Class rules require the underwater hull, rudder, propeller, sea chests, and shell fittings to be examined out of the water, so the special survey, the most extensive of the periodical surveys, is normally aligned with a drydock visit. Within each five-year class cycle a ship must have two bottom (docking) surveys, with the interval between them not exceeding 36 months; one of those dockings coincides with the special survey. Eligible ships may substitute an in-water survey (UWILD) for one intermediate docking subject to class approval.