Freeboard

Freeboard is the vertical distance from the waterline to the upper edge of the freeboard deck at the side, setting the reserve buoyancy a ship must retain. It is assigned under the International Convention on Load Lines, 1966 (as amended by the 1988 Protocol), not SOLAS, and is marked by the load line and Plimsoll mark. SOLAS references the load line through Chapter I survey and certification: the International Load Line Certificate sits alongside SOLAS certificates and SOLAS II-1 subdivision draws on the same reserve-buoyancy concept. The 1966 Load Lines Convention assigns freeboard from tables corrected for hull form, superstructure, and sheer.