Numeric scale painted on the bow, mid, and stern of the ship indicating the depth of submergence at that point.
Regulatory detail & full definition
Required by Load Line Convention. Measured in metres (international) or feet (some US flag). Read at six points (forward port + starboard, mid port + starboard, aft port + starboard) before/after cargo for draught-survey calculations. Modern shipss often have hydrostatic-pressure draught sensors as primary read.