the surfacing of the buoy being assisted by a gas released or generated on submergence of the buoy

Full Title

Buoys ( means for indicating the location of underwater objects B63C7/26; life-buoys, e.g. rings B63C9/08; ) > anchoring arrangements > having means to release or urge to the surface a buoy on submergence thereof, e.g. to mark location of a sunken object > the surfacing of the buoy being assisted by a gas released or generated on submergence of the buoy