1. The problem statement, all variables and given/known data A submersible with internal pressure of 1 atmosphere is at a depth of 30 meter below the surface of the ocean. At this depth, what is the upward force required to open a hatch of area 0.75 m2. Assume density of sea water is 1030 kg/m3. 2. Relevant equations P = Patm + ρgh F = P*A 3. The attempt at a solution Do I have to add the atmospheric pressure on the surface of the ocean? I have this equation : Patm + ρgh = Pinternal + P2 then F = P2 * A. is this approach right?