Well, in dolly system above, the trailer frame has rollers but they never come in contact with the hulls. Instead, the dolly frame (which is lightweight square aluminum tubing) rides on the rollers when loading and unloading. When actually on the trailer, the dolly rests on rubber pads and the dolly frame pins securely onto the trailer frame. The dolly itself has 4 molded cradles (fore and aft for each hull) that the boat rests on. Beach wheels are attached at the aft of the dolly, and a crossbar at the front provides a place to lift and grip. It is well enough balanced that I doubt it takes more than 20lbs of force to lift a 285lb boat. To unload, he lifts the front handle. The rear of the dolly pivots down onto rollers and he rolls if off the trailer onto the beach wheels. To load, he lifts the front of the dolly onto the rollers and pulls the dolly back up onto the trailer frame. It's surprisingly easy.

Regards,
Eric