SART (Search and Rescue Transponder)

A SART is a radar transponder carried in survival craft that, when triggered by an interrogating 9 GHz (X-band) radar, replies with a series of 12 dots that appear on the rescuing vessel’s radar as a line of blips extending outward from the SART’s position along its bearing. The performance standard is IMO Resolution A.802(19). It is part of the GMDSS locating equipment, with at least one required on cargo and passenger ships, and is detectable to roughly 5 nautical miles by a ship’s radar and much farther by aircraft.