i've trasnported a lot of boats on a lot of different vehicles.

if you've got a rack, take some straps like these, http://www.llbean.com/webapp/wcs/sto...5686476-Nextag and go under the rack on one side, over the canoe, and under the rack on the other side and join. Do this at the very back of the rack and very front of the rack.

the canoe is widest in the center, so if this is done on either side of the widest point, this should be all that is needed. If you want additional peace of mind, you can run straps from the bow and stern back to the racks.