Kayak on the back of a Travel Trailer (?)

I have been told about the twist too. it will also help the kayak as vibrating straps can damage the surface or shred themselves if they vibrate over a sharp edge. Just think of it this way, have you ever taken a blade of grass and held it between your thumbs and blew across it? You will get a loud shrieking noise. I think the same principal applies to straps being taunt and having wind blown across them.
It is annoying and I have stopped to readjust them on several occasions. I have mine atop a bed rack.