I recently ran across these instructions for tying fenders on your rail with the simple spar hitch. I am going to try using it this coming boating season.
I use the same as Dr. Bob does. Additionally, if you have more line at the "running end", (which you usually do), a series of half hitches around the standing part create an artistic nautical finish as well as keeping the running end from flapping in the breeze against your beautifully waxed fiberglass vessel. (The fenders that I have secured to the grab rails on the top of "Sea Shift" are attached in this manner).