She carried 24 lifebuoys and 2,340 lifebelts. They jumped overboard with lifebuoys and oars for buoyancy. As a result, some troops nicknamed them "lifebuoys". They used two sacks filled with coconuts to act as lifebuoys. In the United States, Coast Guard approved lifebuoys are considered Type IV personal flotation devices. Real-world objects that approximate a "solid torus" include O-rings, non-inflatable lifebuoys, and ring doughnuts. In these locations, lifebuoys have been superseded by devices such as the torpedo buoy.