PURPOSE: To eliminate Karman vortex as well as vibration or oscillation of a retractably moored light buoy having a buoyant body in the middle of the pole, by making the buoyant body composed of a cylindrical drum at the center and cones on both sides for effectively straightening the water flow.

CONSTITUTION: A buoyant body 2 is fitted in the middle of a pole buoy 1. The mooring ring 3 at the lower end is connected through a mooring cable 4 to a sunken weight 5 on the sea bed so that the buoyant body 2 is always kept under the water for standing the light buoy upright out of the seawater. The buoyant body 2 is composed of a cylindrical drum 2' at the center and conical crown 2" and tail 2"' on both sides, which can increase the straightening effect of water flow to eliminate turbulent flow, Karman vortex and vibration or oscillation of the buoy.