After about 60kmh, the canoe starts to make a whining sound due to wind passing between the roof and canoe - is this normal? Can you still drive on faster or will more wind start to catch the underside of the canoe making it dangerous?
Not dangerous. It may be air resonance
with your rack. Try tying some socks over the rack, and see if it breaks up the resonance.
There are a couple of overpriced “solutions” offered if you have Yakima racks. One is to buy a couple of Windjammers, snap on streamlining devices. The other is to get one of the sloping fairing add-ons. On our cars, the fairing attachment tended to interfere with where the canoes sit. So we’ve used Windjammers.
I don’t know if you’ve done it, but one overpriced accessory I recommend is a set of gunwale brackets. They markedly improve canoe security on the rack.
…
just had it on a set of foam blocks…
In that case
you might try moving the boat forward or back. I’ve noticed that sometimes makes a difference. You also might try putting pool noodles or other type of foam on thwarts, yokes, etc. for transport.
Straps?
Back years ago when I used foam blocks, I can recall there was sometimes a buzzing from the straps vibrating in the wind that could maybe be described as a whine. It was a little like the sounding of a stringed instrument with the boat/car roof was acting as a “sounding board”. Depended a little on wind direction as I recall. Think it was because there was a longer length of strap spanning the roof and exposed to the wind than when using a rack, where the strap is typically very tight to the boat.
It was a little annoying and I suspect it may have shortened the life of the strap a bit. (The “bridge” of the “string” was on the abraded keel of an aluminum canoe which wore at it. I know I used to wear out straps quicker with that rig.) Don’t think its really a safety problem as long as you’re using bow & stern tie downs and replace straps when there’s sign of wear.
Strap noise
– Last Updated: Jul-23-13 5:35 PM EST –
If the straps are buzzing, you can easily silence them by putting a twist in each section of strap that is in the air (not touching the boat). It only takes half a twist. You may notice that truckers hauling very tall loads on flatbed trailers often do this as well, for the same reason. I doubt if they are concerned about the noise, but as Pat points out, a vibrating strap is more prone to wear at its contact points, so for a trucker, stopping that vibration can be a good idea.
One of my Royalex canoes recently acquired a perfect imprint of a strap on a portion of one side of the hull. You can see a perfect replica of the strap, including the weave, slightly "polished" into the surface of the hull. I know the strap was plenty tight, so I assume it must have been vibrating.