The SART (Search and Rescue [Radar] Transponder) is a portable device, which is used as a complimentary distress alerting system. The SART enables any ship/airplane/helicopter in the area to locate survivors easily by just the use of their proper radar system.

The SART is carried to the life raft when abandoning the ship in distress situation. It should be deployed at a height of at least 1 m above sea level and switched on immediately into its Standby Mode. This will allow the SART to respond to transmissions from a vessels/helicopters/planes X-band radar in SAR operations. The SART will give light indication (depends on the SART model) to survivors in the life raft.

SIMRAD SA50SIMRAD SA50 SART

SART example

When the vessels/helicopters/planes X-band radar (9.2 - 9.5 GHz) sailing/flying through the distress zone or executing SAR operations is detected by the SART, it will switch into Transpond Mode. The SART will give audible and light indication (depends on the SART model) to survivors in the life raft.

The response from the SART is received by the vessels/helicopters/planes X-band radar and appears as a line of 12 equally spaced dots/arcs/circles (distinctive "distress" pattern) on a line of bearing from the vessels/helicopters/planes location, with the closest dot indicating the SART location.

Sart signal on the radar

The distinctive "distress" pattern formed by the SART appearing on the X-band radar display

The pattern formed by the SART on the X-band radar display depends on the distance between the SART (position B) and the vessel/helicopter/plane (position A).

SART pattern

When the vessel/helicopter/plane is still more than 1 NM away of the SART a line of 12 equally spaced dots appears.

SART pattern

As the vessel/helicopter/plane approaches to within 1 NM of the SART dots start to change to arcs.

SART pattern

When the vessel/helicopter/plane is at the SART location the arcs turn to circles.



Check the pattern formed by the SART appearing on the X-band radar depending on the distance between the the X-band radar (vessel) position (A) and SART position (B)


Check the pattern formed by the SART appearing on the X-band radar depending on the distance between the the X-band radar (helicopter) position (A) and SART position (B)

Action to be taken on receiving SART signal

If someone sees the pattern formed by the SART appearing on his X-band radar display, he should:

  • inform the nearest MRCC or SRC as soon as possible (MRCC will hold control of SAR operation and give instructions for effective SAR operation as feedback),
  • try to contact survivors by VHF on VHF CH 16 (survivors may have handheld VHF),
  • try to identify location of SART visually (if possible),
  • alter course to search for a life raft at the SART location (if possible).

Correct deployment of the SART

To achieve the maximum detectable range the SART should be mounted vertically at least 1 m above sea level. Increasing the height of the SART will increase its detectable range. This is because the radio waves it transmits use line of sight transmission.

Additionally the SART must not be obstructed by any metal objects or by an inflatable radar reflector.

If the SART is mounted at least 1 m above sea level and the vessel X-band radar is at least 15 m above sea level, then a detectable range of 5 NM is possible. This can be increased significantly to approximately 40 NM by a helicopter or plane flying at an altitude of 1000 m or above.

The SART is usually supplied with a telescopic pole to enable it to be held at least 1 m above sea level (external mounting). A SART can also be deployed by a lanyard or support strap inside the liferaft (internal mounting).

There is a lanyard attached to the SART, which enables it to be tied to the liferaft to allow retrieval should the SART fall in the water.

SART Mounting

Deployment of the SART: 1 - Internal mounting, 2 - External mounting

Stowage of a SART

A SART is normally stowed in a liferaft but more commonly is mounted at an accessible point on the vessel to enable it to be carried easily to a liferaft when abandoning the vessel, for example next to emergency exit or on the navigation bridge of a ship.

An IMO safety sign should clearly indicate the location of a SART.

IMO SART Safety sign

IMO SART Safety Sign

A SART must be mounted at least 1 m from all magnetic resources like the vessel's compass or stereo speakers and must not be mounted within the main beam of the vessel's radar.

The SOLAS convention requirements

SOLAS vessels uder 500 GRT must carry one SART, all passengers vessels and cargo vessels of 500 GRT and over are required to carry two SART's while ferryboats are required to carry one SART for every four survival crafts. In accordance with the efficiency requirements of the SOLAS convention, SARTs are equipped with a battery, with a capacity of working 96 hours in Standby Mode and 8 hours in continuous Transpond Mode.

Last modified: Saturday, 25 April 2020, 7:50 PM