I think you need the extra crew weight to be able to maximise the hull length in light breezes.
Why would you want to maximize hull length in light breezes ?
Waterline length is only important for the top speed of a sail craft (F16's : 12-20 knots range), something you will not encounter in a light breeze anyway.
In light winds you actually want to decrease wetted surface area and one way of doing that is by shortening the waterline ! Many monohull yachts have specially curved sterns to do exactly that : Shorten waterline length when the craft heels over less (= sailing in light winds)
Wouter
