Answer to Question #259671 in Mechanical Engineering for Jool

Question

A submarine is cruising at a depth of 280 m in seawater with a specific gravity of 1.03. If the inside of the submarine is

pressurized to standard atmospheric, determine the pressure difference across the hull in (a) kPa, (b) bars. The average local gravity is 9.70m/s2.

Answer 1

Find the pressure at this depth:

$$p=\rho gd=(SG·\rho_w)·gd=1.03·10^3·9.7·280,\\ p=2797·10^3\text{ kPa}.$$

Since the air is pushing on this water with the atmospheric pressure and the same atmospheric pressure is resisting from the inside of the submarine, the determined value is the pressure difference. This is equivalent to $27.97\text{ bar}.$