WOW... the info in that KayakAcademy guide was amazing... really interesting and exactly what I was looking for.
Especially liked where it debunked the whole 'longest boat is always fastest' myth. They pointed out that hull speed is more your top end limit, and that wetted surface area is really what's going to weigh on your cruising speed. Too much WSA = lots 'o drag.
So maybe I don't
automatically need an 18-foot boat. Hmm...