from the “Best of Sail Magazine’s Things That Work”, International Marine, Camden, Maine, 1998.

Also attached to the bottom of the fender is a 3-inch stainless-steel snap hook, which is hooked to 35 feet of 1/4-inch three-strand nylon line.  The other end is tied to the anchor.  The line has 3-inch loops tied every 5 feet, each marked with the distance to the anchor (he used a small piece of Tyvek threaded through the line).  Ten feet above the anchor Steve tied a small, 3-inch pool float to keep the excess rode from snagging on the anchor or the bottom.  The last step was to write his boat’s name and “anchor” on the sides of the buoy. 

The length of the tether can be adjusted by hooking successive loops into the snap hook until the desired length is achieved.  Steve notes that he sails in the Great Lakes and doesn't deal with tidal ranges.  He admits that while his system is quite complex (compared to 40 feet of line tied to a Clorox bottle), knowing exactly where his anchor is set makes it all worthwhile.