Sometimes when the bay freezes over many mariners and people with docks and boat slip lose their dock poles. The ice causes the poles to lift and eventually come loose, like this one around the block from where we live. My in-laws have a dock and have lost poles in the past. I'm not sure how they faired this season.
Some people put in bubble systems that keep the water moving around the poles and prevents the water from freezing. The system works when the winter doesn't have a long cold stretch that freezes the moving water.
Made with the Canon G10 and processed with ACR.