-- Last Updated: Oct-10-12 3:09 PM EST --
Same experience here. And, here's a link to the aforementioned truss hangers. The flat edge goes under the gunwale. You can make 'em yourself.
P.S. You're also lees likely to break the bolts with truss hangers as the do not flex much.
Paddler's Truck Rack
Free Standing Boat Racks