My buddy and I are converting a 4X6 utility trailer into a canoe trailer this weekend.  We plan to build a box that slides in and out of the existing trailer (adds versatility).  We will build support racks up from the box to hold two canoes.  

QUESTION: my friend thinks the canoes, when loaded on the trailer, should not be higher than the roof of the truck we use to tow with.  I think he said Cliff Jacobson wrote about this in a canoe trailer he described in one of his books.

My thinking: if canoes can get tied to the top of trucks, who cares if they are a bit higher than the roof of the vehicle when strapped to a canoe trailer?  Surely the "drafting" effect can be that bad?  

Thoughts?  Other considerations?   I want this built before our QP trip June 1!!

prouboy