A ferry-boat is rectangular in shape, with an overall area of 30.0 m2. When the boat is loaded with gravel, it sinks to a depth of 2.8 m in the water. What is the total weight of the boat + gravel? Show your work.

the total weight must be supported by the displaced water, the weight of which is equal to the boats weight.

The weight of the volume of water displaced is equal to volume/density*g*