Answer
The water in Mississippi river is less salty than ocean water.
Salt water density is higher, so less sea-water which contains more salt than harbor water needs to be displaced to exert the same buoyant force. Thus when a ship is in sea water, the Plimsoll mark will be above the water level.
Work Step by Step
The water in Mississippi river is less salty than ocean water.
Salt water density is higher, so less sea-water which contains more salt than harbor water needs to be displaced to exert the same buoyant force. Thus when a ship is in sea water, the Plimsoll mark will be above the water level.
