ABSTRACT
The tropical and winter lines are then placed l/48th of the ship’s summer draft above and below the summer mark. The fresh water lines are placed above the summer line so that a ship floating to this line in fresh water would rise to her summer or tropical lines when sailing from fresh to salt water. A ship is required under the International Loadline Rules to be loaded to her correct loadline when she enters a zone at sea as well as when proceeding to sea after loading a cargo. A ship arriving at a boundary port must be loaded for the zone that she passes through on the way to the port. In order for a ship to be correctly loaded at all stages of the voyage it is necessary to calculate the tonnages that she can lift at different stages of the voyage.
