Can anyone tell me what this is

Are we supposing its related to boating? It is obviously has the clamp incorporated. But where it goes is a mystery for sure. Is the peglike object removable?
Actually it is lying on its side. If you put it in the proper orientation it may be easier to identify - wheel up and screw handle down. AH! there it is... it is a portable (or perhaps perminent) dock roller. It can be attached to a dock side (best used on a corner) to allow a heavier boat to dock without gouging the side. The boat will simply contact the roller, compress it a little to absorb a bit of the energy and then roll along the dock without damaging the boat. Very useful with heavy boats. I once had a boat of just over 20 tons that was fun to get into a slip. I had to come down a narrow channel with slips on both sides. To dock I had to make a 90 degree turn and the wind was always strong abeam as I lined up with the slip. Without rollers the dock would have had a bite of my fiberglass every time I came or went from my slip. Thank God for these devices.

If that is not the correct answer then I don't have a clue....