A scheduled period when a vessel is taken out of service and placed in a dry facility for hull inspection, maintenance, and repairs.
In practice
A drydock programme typically encompasses hull blasting and repainting with antifouling and anticorrosive coatings, inspection and renewal of sacrificial anodes, sea valve overhauls, propeller polishing or replacement, rudder bearing renewal, and tailshaft survey. The technical superintendent and chief engineer co-ordinate the work specification and supervise the execution on site. IMO Resolution A.744(18) on enhanced surveys of bulk carriers and tankers (ESP programme) specifies detailed inspection requirements for high-risk vessel types that must be completed at drydock. Accurate repair specification and tight project management are essential to control costs and minimise off-hire periods, which can represent a significant loss of revenue for the shipowner.
Regulatory detail & full definition
A drydock period is a scheduled out-of-service interval during which a vessel is placed in a graving dock, floating dock, or slipway so that the underwater hull and all related equipment can be inspected, cleaned, and repaired without the obstruction of water. Classification societies require a drydocking survey every two and a half years for most vessel types, with the Special Survey conducted every five years coinciding with a full drydocking and structural inspection. SOLAS and MARPOL certificates are also renewed at drydock intervals.
A drydock programme typically encompasses hull blasting and repainting with antifouling and anticorrosive coatings, inspection and renewal of sacrificial anodes, sea valve overhauls, propeller polishing or replacement, rudder bearing renewal, and tailshaft survey. The technical superintendent and chief engineer co-ordinate the work specification and supervise the execution on site. IMO Resolution A.744(18) on enhanced surveys of bulk carriers and tankers (ESP programme) specifies detailed inspection requirements for high-risk vessel types that must be completed at drydock. Accurate repair specification and tight project management are essential to control costs and minimise off-hire periods, which can represent a significant loss of revenue for the shipowner.