Answer
“No, not always. Even if cargo density is same, the amount that can be carried depends on the density of water in which the vessel is floating. In freshwater the density is lower, so for the same displacement the vessel sinks deeper. In seawater the vessel floats higher because buoyancy is more. Therefore cargo quantity is limited by load line, freeboard, draught restriction, stability and strength. If loading in freshwater for proceeding to seawater, freshwater allowance or dock water allowance may be used. But if the vessel is loaded in seawater and has to enter freshwater, draught will increase, so same amount may not be permissible if load line or under-keel clearance becomes critical.”