All ages tend to remember their first ride on a catamaran. Your mission is to guarantee it's a good memory. Offer a little free clinic on the H16 before the regatta (same day or other day) so they aren't stepping onto a completely foreign platform without any instruction.

Why accept an arbitrary age boundary (high school/college) as a limitation? Unless there's some restriction to the event organization that forces a choice just keep it open to all those teens. See which groups the event is more attractive to this year and hone it for next year.

Also, I'd be very careful about stepping on toes. Make sure the various teams and clubs understand you are not trying to muscle in on their turf. Keep everybody happy and smiling.