Say a submaine has an area of 4.5m X 2.3m and it is 304.8m below sea level. And that the density of the seawater is 113.4 kg/m2

what is the pressure exerted on the submaine by the water above it?

The weight of the water above it is Volume x density x gravitaional field constant g

pressure= weight/area=g*area*density*304.8m/area
pressure= 9.8m/s^2*113.4kg/m^3*304.8m
= 9.8*113.4*304 N/m^2