A sunken battleship weighs 40 000 tons. It may be considered to be all steel, SG = 7.9. (a) We now propose to raise the battleship by sinking steel tanks adjacent to it, attaching them to the battleship, and then blowing the water out of them with compressed air, making them buoyant. Assuming that the compressed-air tanks will have negligible mass, what volume must they have to raise the battleship? Assume that the battleship is in seawater and that the insides of the battleship are completely filled with water.

answer is 1.084x106 ft3

please explain