Graving Dock
Permanent excavated dock with a gate; fills with water to receive the ship, then is pumped dry for hull work.
In practice
Vessel in graving dock typically 12-21 days for class drydocking. Hull washed, anodes / ICCP renewed, propeller polished, antifouling applied. Yard quality control significantly affects coating life.
Regulatory detail & full definition
Permanent excavated dock cut into a quay wall or shore, sealed with a gate or caisson, and fitted with pumps. The dock is flooded to receive the ship floating in, the gate is closed, and the dock is pumped dry, leaving the vessel sitting on keel and side blocks for hull access. Graving docks accommodate the largest vessels and provide stable working conditions for major repair, conversion, and renewal work. Modern graving docks at major shipyards (Hyundai, Samsung, Imabari, Sembcorp) handle VLCCs, ULCVs, and FPSOs.
Related
Source: Industry usage
High confidence
Editorial confidence: how we grade.