I cannot follow this logic. Every kind of "club" dinghy has a daggerboard, even an Optimist. Hence if a kid can handle the daggerboard or a Laser, Pico OpenBic, Optimist, 420, 470, 29, Topper Taz, Topaz or wahtever, he or she can do this on a cat as well.
Maybe you can mark "1 foot" with a permanent pen on the board and it is kid proof.