Draught(also “Draft”). This is the vertical distance between the waterline and the keel. During construction of a vessel, the marks showing the draught are cut into each side of the stem and sternpost and clearly painted from a certain distance below the light draught to a certain distance below above the loaded draught.
Sometimes the draught is also indicated on both sides amidships near the loadlines, so that if the vessel should show signs of hogging or sagging in the course of loading, this can be noticed immediately by comparing the draught fore and aft with the draught amidships.
If the mean draught amidships is greater than the mean of the forward and after draughts, the vessel is “sagging”. It is “hogging” if the amidships mean draught is less than the mean of the forward and after draughts. This is -taken into account when a draught survey is carried out to determine the quantity of bulk cargo loaded. The draught surveyor can calculate the draught in different, ways depending on the practice of the firm to which he belongs. Generally, he will take into account if the vessel is hogging or sagging and calculate the means and the mean of means”. An allowance is then made for the parabolic shape of the underwater volume if the vessel is sagging (as is usually the case with bulk carriers and oil tankers) and the deadweight calculated based on this allowance and the vessel’s deadweight scale or displacement tables.
The draught is indicated in feet and/or decimetres. The figures indicating the draught in feet are consecutive and six inches high. The lower side of the figure indicates the draught in feet and the upper side shows the draught in feet, plus six inches. In the event the draught is expressed in decimetres, only even figures with a height of one decimetre are used. The lower side shows the draught in decimetres and the upper side indicates the draught in decimetres, plus 1 din.