Draft mark

Draft marks are the numerals welded or painted on the stem, stern, and amidships on both sides of the hull that let an observer read the draft at the perpendiculars directly off the waterline. They are conventionally 100 mm (or 4 inch) high figures spaced so the bottom of each numeral marks its stated draft, in meters or feet. Reading the six marks (forward, midship, after, each side) gives the drafts used in a draft survey to find displacement from the hydrostatic tables, the standard method for weighing bulk cargo by difference. Accurate marks and a correct reading, with corrections for trim, hog or sag, and water density, are the basis of commercial cargo quantity determination and load-line compliance.