Draught is the distance from the keel to the waterline (WL), as measured at the forward and aft ends of the ship.
More precisely the draught readings are taken as those read at the Forward and Aft Perpendiculars. It is expressed in meters. If the draughts forward and aft are the same then the ship is said to be on an even keel (as shown).
The draught of the vessel changes with the change in the density of water
If a ship moves into water of lesser density, the draught will increase.
If a ship moves into water of greater density, the draught will decrease.
DRAUGHT MARKS AND READING THE DRAUGHT (DRAFT READING)
The draught marks on a ship should be marked at the Forward and Aft Perpendiculars on both sides. The numerals are 10 centimetres in height and are spaced 10 centimetres apart as shown.
The draught is read as shown in Figure using the lower edge of the numerals. Intermediate values have to be estimated. If the water is quite choppy then great accuracy will not be possible.
What is the draught reading for each of the waterlines shown in below Figure?
(a) 2.80 m
(b) 2.50 m
(c) Approximately 2.37 m
(d) Approximately 1.82 m