Load line

The load line, or Plimsoll mark, is the statutory marking on a ship’s side showing the maximum permitted loaded draft, ensuring a minimum reserve of buoyancy as freeboard. The International Convention on Load Lines 1966, as amended by the 1988 Protocol, assigns freeboard by ship length, type, and structural strength, and marks seasonal and zonal limits (Summer, Winter, Tropical, Fresh, and Tropical Fresh). An International Load Line Certificate is issued after survey. The mark ties directly to deadweight, draft surveys, and the carriage of safe cargo quantities.