This is at table of the hull half-widths in inches, stations are 12 inches apart. The bow is Station 0. Above the datum line the hull can be vertical sided, below the datum line, the hull is a semicircle with radius as in the table. Its basically a circular arc, formula of a circle is r^2 = x^2 +y^2 y = sqrt ( r^2 - y^2 ) - put this into a spreasheet and input R=1410 inches and you get this arc...