Bottom Contours on Retro 9’6" Been working on templates for a retro 9’6" 15.5 - 22 - 16 – 50/50 rail – ordered a 9’9"W Clark blank with the wl rocker adjustments. The Hansen Red Fin is my inspiration. I am wondering what the bottom contour should be. I have noticed a lot of these boards are rounded across the bottom from rail to rail. I would love to have some input from those who have shaped this type of board. Thanks Scott
Hey Scott I just made a traditional 50/50 railed 9’4" from that blank, with almost those exact dimensions. If you want pictures post (or email) your email address.
Scott, I like the feeling of surfing a rounded bottom board. It’s pretty unique. There’s more board in the water and it might be said they capture more depth of energy from a given wave. After you have your board to desired thickness, start working some v into the tail, then transition to more of a roll all the way up to the nose. Do so by making shallow cuts out from center towards the rail until you have stepped the bottom. This should be very gradual and even on each side of the stringer, so take time to insure each side mirrors the other. Blend those lines with shallower planer cuts and then go to 80 grit. A sanding screen contoured to the roll is also helpful. How much roll is up to you and will determine how pinched your rails are. 
a nice roll on the bottom keeps the board moving through choppy water. it almost acts like a subtle hull, depending on how much roll you give.
What if you can’t get that roll ? Assuming I build a hollow woodden board, I guess I could only have a flat deck and a flat bottom (is that correct Paul ?). Let say the board is a typical “retro” longboard, 9’8" x 23" x 16" x 15" x 3", 50/50 rails, 3.5" nose rocker, 3.75" tail rocker, heavy weight. What would happen if instead of a convex deck and bottom, you end up with flat deck and bottom ? How would the board ride ? Pierre