What is the strongest and lightest ply wood species? Could you get away with 3/8" on a slightly smaller board ,say 145 x 45 ?

Does 3 coats of varnish keep it waterproof ? Maybe just apply another coat once / year ?

All my boards are only 3/8" thick, including the 150x46. For a wood board made of birch with a simple flat bottom it won't work unless you cover it with glass. In a properly constructed concave board it works without glass.

For a wood board with the best strength to weight ratio try sitka spruce - Ive looked into it and the materials for a conventional foam/glass/carbon/epoxy composite are acutally less expensive.

Trent Hink

How does a concave make the board get on the plane faster?

All the true light wind boards I`ve seen are flat!

Dude, I explained why just a few posts up in this thread - go back and read it.

Maybe you just haven't seen enough boards. Check out the bottom of a surfboard sometime, use a straightedge if you need to. NEARLY ALL modern surfboards use some form of convave.

The majority of the production kite boards I've seen are true pieces of crap, especially for light wind. That has only slowly begun to change in the past one or two years so keep your eyes and mind open.

a few yeasr ago I got the Litewave Dave 181 board, put some SS footpads on them. @ 195 lbs, and South Florida, I can get on the water with my 19m kite. Especially now that the 5th line maes the kiet go upwind better and turn faster.
Look 4 this board, cheap, 2002 model and great planing surface, with =out all the expenses.