The old breakwater in Port Erin has been closed to the public after storm damage left large hole in the breakwater, leaving it unsafe.
Part of the stone wall of the breakwater was carried away on the harbour side and a large amount of infill was washed into the bay.
The cavity is the size of a small car, and the concrete decking is now unsupported in the area and remains dangerously unstable.
Department of Infrastructure engineers are investigating the damage. However, it is unclear at present how long the breakwater will remain closed.