Absolute pressure at an ocean depth

[jenha14]

a) Calculate the pressure at an ocean depth of 550 m. Assume that the density of sea water is 1022 kg/m3 and that the air above exerts a pressure of 101.3 kPa.
b) At this depth, what force must the frame around a circular submarine porthole having a diameter of 32.0 cm exert to counterbalance the force exerted by the water?

I found the answer for (a) to be 5609880 Pa, but I am stuck on part (b).

[mgb_phys]

Assuming the inside of the sub is at atmospheric pressure all you need is the water pressure at that depth.
Since pressure is force / area. You have the pressure,you can get the area of the porthole so hat is the force?