Basin

A basin is an enclosed or partly enclosed water area inside a port, sheltered enough for berthing, turning, or layby at near-still water. Types include the harbor basin where vessels berth, the turning basin sized for swinging, the tidal basin open to the tide, and the impounded or wet dock held at constant level by a lock or gate. Plan dimensions follow the design vessel: berth basins give clearance for fenders and tugs, and a turning basin is commonly 1.5 to 2.0 times the vessel length overall in diameter. ROM 3.1 and PIANC guidance govern basin layout, wave penetration limits, and water depth.