boats on roof
I've been car-toppin canoes for many, many yrs. I graduated a long ago from homemade to a Yakima system & don't regret it for a moment although I'm sure those handier than I could build a safe, secure system & save lots over price of a commercially made rack.
Currently I'm carrying my boats atop my 06 dbl cab Tundra which also has a cap. Canoes range from 16-18.5 ft & to get sufficient spread I mounted one crossbar on cab & other on cap. This also allow them be be mounted forward enough to not interfere w/ trailer but w/ a 10' craft you shouldn't have to bother. We put 9500m on each of last 2 winters traveling cross-country & wintered in FL prior to that. Never any problems car-toppin'
Here's my $.02: Use gunwale brackets. These will keep the boat from shifting sideways in wind. If your jonboat is wider in center than bow or stern, they'll also help prevent (but not gaurantee) it's sliding forward or backward. For that you'll want bow & stern ropes. Over the belly use 2 straps, not ropes & don't bother w/ those w/ the built-in ratchet system which can put undue stress on your hull. Rather than try to pad your hood where bow rope contacts it try this: Open hood. Remove one bolt from under edge. Fold a 12in piece of nylon strap in half & fasten loose ends w/ grommet. Re-intall bolt thru grommet. Tie bow rope into strap loop or hide under hood when not car-toppin'. A temp extension on your crossbars (smaller diam pipe/conduit if using round bars) will make loading & unloaded much easier & save possible scratches on your cap. Expect a mpg reduction, negligable if your towing but 2 mpg if you're not.
