[bcmarinamanager]

It is called a closed chock. It is used a lot on blow boats to keep their lines from tangling too much. The top bar is threaded, so you can screw it out and release the anchor. i set it up just far enough back so that I have to pull the anchor tight and just get the screw bar into the chain. It also helps when hauling the anchor because I can keep it closed while I'm hauling the rode, and it allows me to stay farther back in the boat. If need be, I can pull the anchor out while standing at the console, in cases when it is windy and I'm single handed, then I just tie it off to the T-top temporarily.