Load and pressure centre of a vertical panel

A vertical rectangular inspection panel is fully submerged in still fresh water of density $1000\,\mathrm{kg/m^3}$. Its horizontal width is $1.25\,\mathrm m$ and vertical height is $1.80\,\mathrm m$. The upper edge is $1.40\,\mathrm m$ beneath the free surface. Calculate the resultant gauge-pressure force normal to the panel and the vertical depth of the centre of pressure below the free surface. Use .