I just bought a used royalex OT camper, and when I load it on my factory roof rack, one of the corners does not rest on the rack. I can wobble it a bit versus the diagonal corner - think wobbly table. The gunnels look okay, but how can I check if it is the canoe or the rack causing the problem? It tied down fine, but I’m concerned I am more likely to damage the hull when tightening to the rack.
... those are the best kind. They help keep tension on your straps**. What are you talking about ... like a 1/2 inch or less? It's not uncommon and doesn't matter.
** tung in cheek
Wobbles on the rack
Stand at the front or rear of the car and position your eyes at an elevation such that the top edge of the cross bar farther from you is “just” visible beyond the cross bar that’s closer to you. If the two bars are not parallel, you will be able to tell. If the difference is too small to see, it’s too small to matter.
It is not uncommon for boats to act the way yours does when resting on parallel roof bars. I don’t have data to back this up, but given the flexibility of Royalex and the fact that except for certain kinds of warpage, it takes a pretty big deformation to noticeably change how a boat handles, you probably have nothing to worry about. If the amount of wobble is severe (maybe something getting near an inch), you could put a little extra padding under the gunwale at one location to reduce how much the boat gets twisted when the tie-downs are tight.
It is less than 1/2 inch, so I’m glad to confirm I shouldn’t worry about it. Thanks!
“Tung” in cheek
How’s that tung oil taste anyway? And does it give you a buzz like tobacco?
Dun’t fret none 'bout it. Most ah’s seen got dat.
it tight on the cross bars.
That will correct the warpage.
It’s pretty unlikely your rails warped, much more common for rails to not have been forced down flush with the hull top edge when installed.
I have seen wood railed boats where the mounting screws missed the hull entirely, which is a problem, but with vinyl rail’s deep channel there is not much chance of that.
with enough warp
you can paddle on one side and go straight, which is most flatwater paddlers dream now, isn’t it?
....... I'm guessing from your discription , you are calling warped to mean what I would call twist .
You can easily check a canoe hull for twist to see if it is ... (warped that way) .
Could be in the load bars like already mentioned ... sighting them to check if they are parallel with each other in the vertical plan will confirm or deny that right away .
Best to take a few slugs of Southern before attempting any of the above if you've never done either .