Join Date: Feb 2009
Location: Northeastern BC
Yeah, I can't see those racks that mount directly to the roof of a fiberglass canopy being able to bear much weight. Eventually the fiberglass is going to start cracking from stress. I had crossbars like that on the canopy of my old truck, but I never put anything other than a few pieces of lumber or a foam mattress up there. There were only 3 or 4 screws per corner holding it on with a backing plate, inside. The weight of a boat would have probably wrecked it.
What if you got an external frame type, as you mentioned, and have it raised a bit, by cutting the legs, and welding in a few extra inches of tubing (enough to clear the roof of the canopy)?
If Princess Auto were a real girl, I'd ask her to marry me.