For a central mooring chain the internal tube is reinforced . Smaller marker buoys (500mm) lift aboard when boat is moored. Floats can be permanently in the water with fixed through rod and eyes where the mooring rope is attached to the top eye and used to moor the boat or with a central tube through which the mooring chain lifts to attach to the boat. The tear drop shape of the buoy reduces strain on moorings in rough seas.