Roof tiedown noise

Bought a used canoe, love it. When carrying it on the roof there is a howl starting at 40MPH that makes fingernails on a blackboard soothing. Any suggestions how to quiet the straps down?

Twist…
Put a twist or two in the strap where a section is free running and exposed to the wind

Roof tie down noise
Thanks for the help. I will try next weekend. LBJ

little piece of
(thin) sleeping pad material (EVA) between the straps and the canoe hull

http://www.xs4all.nl/~dbarends/images/eva.jpg

works for me.