Search and rescue transponder
![A standard SART 9 GHz radar transponder, produced by Jotron, on board a Norwegian ferry. The unit is 251 mm high.](/Images/godic/202502/09/SART_radar_transponder1010.jpg")
![A mockup radar trace from a SART transponder, with the location of the transponder in the trace.](/Images/godic/202502/09/SART_radar_trace.svg1010.png")
A search and rescue transponder (SART) is a self-contained, waterproof transponder intended for emergency use at sea. These devices may be either a radar-SART, or a GPS-based AIS-SART (automatic identification system SART).
The radar-SART is used to locate a survival craft or distressed vessel by creating a series of dots on a rescuing ship's radar display. A SART will only respond to a 9 GHz X-band (3 cm wavelength) radar. It will not be seen on S-band (10 cm) or other radar. Shipboard Global Maritime Distress Safety System (GMDSS) include one or more search and rescue locating devices.