good point hobie1616. <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />

Maybe spread some silicome sealant on the straps, cover with polyethylene plastic, and then put the boat in it till the silicone sealant sets and then remove the boat, then pull off the polyethylene, so the silicone would take an impression of the hull. This would make the straps non-slip. This might cause some minor chafing?

Or maybe have two straps at each station. Each strap starts at the top on opposite sides, then goes down and part way up the other side where it is attached... Creating a rounded X ... The bottom part of the X would be flattened out... This should stop the fore and aft swaying and lateral swaying.

As fate would have it, I have some old heavy heavy webbing that was used to carry sling loads below a helicopter.

Has anyone tried supporting the boat by the crossbars?