The lifebuoy is a flotation device in the shape of a ring. Passenger vessels are required to carry at least eight lifebuoys with lights that come on when immersed. In reality, they carry more than this minimal number.
Lifebuoys are an essential part of a ship's safety equipment. They are stowed around the deck such that they can be quickly thrown into the sea in man-overboard situations.
SOLAS regulations cover lifebuoy technical requirements. In general, it is made of solid cork and painted orange (or another high-visibility color), with reflective strips and grablines. Some have a lifeline, a floating automatic light or smoke flares. The buoy is made of an inherently buoyant material. It should not be made of a loose granular material, and should not require inflation.
