Brackish water is water that has a density between that of fresh water (1000 kgs/cubic metre) and that of salt water (1025 kgs/cubic metre). When a ship is required to proceed to a port where the water density is brackish, the ship’s draught will be more than the draught in seawater and less than the draught in fresh water. Normally, the difference between the seawater draught and the fresh water draught is the full “fresh water allowance”. In this case, the draught will have to be calculated using the measured water-density and perhaps notified to port agents and/or charterers.
