The Disney Magic cruise ship has a "displacement" (or weight) of 85,000 (US) tons. Its Iength is 964 feet and its beam or width is 106 feet.

What is its "draft" or depth? That is, how far below the water line does the ship go?

You will need to make some reasonable approximations to solve this problem.

The density of sea water is 1025 kg/m3.

Converted to SI units, the Disney Magic has a displacement of about 77,000 metric tons (that is, about 77,000 x 1000 kg's weight or the weight of 77 x 106 kg). It's length is 294 m and its beam or width is 32 m.

However, those are maximum dimensions. At the water level, consider the Magic's hull to be a rectangular solid with a length of 280 m and a width of 30 m. What is its "draft" or depth?


89 m

18.9 m

8.9 m

0.89 m

(c) 2000, Doug Davis; all rights reserved