So, for that purpose, we assume submerged column as you can see here. And the prime view, the top view is I have shown here, the diameter is 2 a, on the height of the column is h, in the water depth of d. So, we consider o - the centre point of the column at the sea bed as the point at which you might be interested knowing the moment. So, the force is acting in the horizontal direction ,and the vertical direction are represented can be seen as can be seen here, and here. And this horizontal force is expected to act at a distance of z from the sea bed, and the horizontal force, vertical force is expected to at from a distance x.