good selections, I wanna run shuttles with you bob!
Is your nickname " what?"
The straps, position of boat, readjusting rack are all good “fixes”…if they don’t work, consider checking your rudder if you have one, and/or foot braces to make sure they are locked in transit so as not to vibrate at higher speeds.
One responder said, “Twist em”. That always worked for me.
Wherever you have a strap in tension that is flat to the wind for a foot or two, that strap can “sing” or “roar” in the wind at highway speed. One full twist per foot of strap that isn’t touching a hard surface should stop that noise. Other things can also “sing” in the wind, like a loose rope end, or even a seat back. If a taught rope is singing, tie another rope or a bungee to it to stop the vibration.
Round rack bars can also generate noise like “moaning”, when nothing is on the bars. Air vibrating around them at highway speed can cause noise. You can take a piece of outdoor carpeting about as long as the bar, maybe 10 inches wide, and wrap or loop it around each bar. Sew, glue or otherwise fasten the carpet to itself (backing side to backing side) on the downwind side of the bar, thus creating an approximate airfoil shape. Cut it away as needed for straps, supports, etc.
Large holes in a flat plate parallel to airflow can also generate “moaning”. I learned about this when I made a roof rack using flat aluminum plates to support the bars. I killed the noise with door edge guard material on the leading edge of each plate.
No need to put up with wind-induced vibration. No need to turn up the radio. No need to buy anything.
Had the same problem. Solution: Half way up the strap, tie an old sock or a rag onto the strap.
Do NOT ignore the problem the way some people here are advising. That rapid strap vibration will break down the strength and integrity of the straps, and eventually they will fail. Then you have a loose kayak flying off your roof and causing a traffic accident that could kill people.
The number of twists depends upon the length of the section of strap. I like to use a half twist per foot of length exposed to the wind. The longer the unsupported strap, the more twists you will need.
Also see this article, here:
https://thcc.clubexpress.com/content.aspx?page_id=22&club_id=496051&module_id=257066
- John Rich