Physics Question about buoyancy?

A circular hatch in the hull of a submarine has a radius of 40.0 cm. The submarine is 850.0 m under water. If atmospheric pressure above the ocean is 1.01x10^5 Pa and the air pressure inside the submarine is 1.31x10^5 Pa, what net force is exerted on the hatch(density of saltwater is 1025 kg/m^3).