I wanted to know what some of you are using for a bouy anchor while you have your boats tied up. Heard of engine blocks, but also that they roll.... buckets of concrete, and even man hole covers. The boats that will be tied up will be in the 25-28 ft range.
Any feed back from you guys on what to use and won't move will be appreciated.

ski course used engine blocks. They never moved

Run the chain through the cylinders?