On Jun 20, 5:05*pm, durabol wrote:
I am planning on building a plane that is towed behind a boat...

Were it I, I'd go with an NACA 23000-series (23012 for 12% t/c or
whatever) and be done with it. Good enough for the 1-26 and 1-23
sailplanes, good enough for the Bonanza and the early Citation
business jet, probably fine for a boat-towed glider toy.