Is your bike rack full of clamps, claws, and cleats that might get bent while carrying your sunfish? Or, is the free boat you found on Craigslist likely to develop another crack if tied down against your rack? Tie a couple of 2x4s to the rack with innertubes and head to the beach!
Step 1: Tie 2x4s to the rack
Find some old 2x4s and tie them to the rack with innertubes.