Draft Marks

Draft marks are the numerals on the bow, midship, and stern that read the vessel’s draft against the waterline. Metric marks are Arabic numerals 10 cm high spaced 20 cm apart, so the waterline cutting the bottom of a figure reads that decimeter. Reading forward, midship, and aft marks gives the mean draft and the trim; the draft survey method uses them with hydrostatic tables to compute cargo loaded by difference, a primary tonnage check on bulk carriers.