Hi everone I have a second drawing on the board this winter and achieved a rather good and fair hull for a 30 ft aol 9' 2" beam and 1' 6" depth. simpson rule calculates under water volume 130.2 cubic ft = 6249 lb. I divide the stations "S" of 2.25 ft by "3" to get .75 and multiply .75 X 130.2 cubic ft and arrive at 97.65 X the weight of sea water 64 equals 6249 lbs Now the problem is if I plug in the numbesr for Cp I get .72 not good! That's 130.2 cubic ft divided by the waterline 22.5 time the greatest station volume 8 square ft what could I adjust to get a Cp of .52 or close Seams to me if i increase the water line that increases the volume on the 130.2 cubic ft on the dividend side and increases the 180 for the divisor changing the Cp very little Thanks in advance Robert from CT