Load Line Loading Mark

Load line marks are the hull markings, centered on the Plimsoll disc, that fix the maximum permitted loading drafts for each season and water density. They are governed by the International Convention on Load Lines, 1966, as amended by the 1988 Protocol, not by SOLAS, though SOLAS I and the freeboard-stability rules in II-1 cross-reference reserve buoyancy. The deck line, disc, and seasonal lines (S, W, WNA, T, F, TF) are cut in and painted permanently. Assigning authority is the flag administration or its recognized organization, recorded on the International Load Line Certificate. The mark is read during draft surveys to verify a ship is not overloaded.