This New Years the wife is demanding that she comes along on the surf trip, therefore will need to carry the SUP on the roof. I have some FCS soft racks that I used to carry my surfboards with, do you reckon that they are strong enough to take a SUP?
I ask because I drove past a guy who was having a 'mare the other day, looked like the thing was trying to take off!
We've transported a lot of gear in the past on soft racks but the issues are:
The weight of the gear goes on to the roof not the stronger sides of the car (sorry have no idea how to describe it technically), so the old Mazda 121's roof would buckle in a bit!
You need to use an extra couple of good quality straps (I like Neil Pryde's really wide ones) then feed them through the car (with the doors open) and do up nice and tight - this'll stop the lifting you mention. Issue with this is that the straps will buzz annoyingly and if it rains the water will seap through the straps and into the car.
So - yes, I think you can but I wouldn't be doing it with a nice car or in the rain!
PS I take ZERO responsibility if something goes wrong!
The car I use is an old Hilux Surf, so no worries with damaging the paint or panels, most of them are showing their age anyways! I think it should have a roof a bit more sturdy than a 121. Would look pretty classic seeing a load of SUPs on the roof of a 121 actually, good on ya!
I might pick up a couple of cheap strops/ ratchets to secure the load down once I have got it all tied on with the soft racks.
I did it with a a race board in the states for a few weeks. As BenKirk said, use an extra good quality strap (the wide ones are better) to secure it through the inside of the car at front and back. I did this and as long as you tie it down tight I had no issues with the board bouncing and it wasn't too noisy either (the noise reduced heaps when I put a twist in the straps on top of and on either side of the board!). The rental car they gave me was a brand new Chevy captiva and after a few weeks and a couple of thousand miles with the board strapped on tight, there was no damage to the roof. Obviously can't guarantee this would be the case for every car but with only one board you should be fine.
when travelling i always use the fcs straps for my sup bag that usually contains a 9'0 and 2 short boards and have no dramas. i just check it every now and then.