A Search and Rescue Transponder (SART) is a device used to locate and rescue vessels or individuals in distress at sea. It is typically used in conjunction with a radar system and is designed to respond to a radar signal with a distinctive signal of its own.

When a vessel or individual in distress activates a SART, it begins transmitting a radar signal that is picked up by nearby vessels or search and rescue aircraft equipped with radar systems. The SART’s signal is designed to show up on the radar display as a distinct, easily identifiable symbol or signal, making it easier for rescuers to locate the distressed vessel or individual.

SARTs are typically required equipment on larger vessels, such as commercial ships, and are also commonly used on smaller vessels, such as pleasure boats and fishing boats. They are an important tool for increasing the chances of survival for individuals and vessels in distress at sea.

Search and Rescue Transponder (SART)

Working of SART – How SART Works

The Search and Rescue Transponder (SART) works by responding to a radar signal sent by a search and rescue aircraft or vessel. When a SART receives a radar signal, it automatically responds by transmitting a series of pulses at a pre-set interval.

The SART’s response signal is designed to be picked up by the radar system of the search and rescue aircraft or vessel, and it appears on the radar display as a distinctive symbol or signal. The rescuers can use this signal to locate the distressed vessel or individual and determine its location and direction.

SARTs are typically equipped with a built-in battery and antenna, and they are designed to be waterproof and floatable. They are usually kept in an easily accessible location on the vessel, and they can be manually activated by pushing a button or automatically activated when the SART comes into contact with water.

Search and Rescue Transponder (SART)

Other Main features of SART

  • SARTs are made of waterproof components which protects them against damage by water.
  • SARTs are essentially battery-operated, hence can be operative for a long time. SARTs are of use in ships, lifeboats and liferafts. They are the most supportive machines in case of an unprecedented emergency. SARTs are designed to remain afloat on the water for a long time in case the vessel finds itself submerged in water.
  • The bright colour of SARTs enables their quick detection, whereas the combination of transmitter and receiver enables it to transmit as well as receive radio signals.
  • SART machines have been instrumental in rescuing several crafts and ships by reacting to the search signal sent from an X-band radar, typically of 9 GHz.  These signals are known as homing signals.
  • The response is usually displayed on radar screens as a sequence of dots on an X band-radar, which helps rescuers reach the vessels in time.

Types of SART – Search and Rescue Transponder

These devices may be either an AIS-SART or a RADAR SART. Global Maritime Distress Safety System (GMDSS) installations include one or more search and rescue locating devices.

RADAR SART – These are widely available in the industry. These types interacts with X- band RADAR and send homing signal to transmit it’s location.

AIS SART – The AIS-SART is a self-contained radio device used to locate a survival craft or distressed vessel by sending updated position reports using a standard Automatic Identification System class-A position report. The position and time synchronization of the AIS-SART is derived from a built-in GNSS receiver (e.g. GPS). 

Global Maritime Distress Safety System (GMDSS) installations include one or more search and rescue locating devices. These devices may be either an AIS-SART (AIS Search and Rescue Transmitter) or a radar-SART (Search and Rescue Transponder).

SARTs find themselves useful in rescue operations involving aeroplanes or ships stranded by air and sea accidents. They are designed to survive the toughest conditions and stay active on elevated positions like on a pole so that they could cover a diverse range. Talking of heights, a SART transponder on an aeroplane could have a range of 30 to 40 miles. This helps to scrutinize a huge range and huge area.

Carriage Requirements of SART

  • Passenger ship- at least 02
  • Cargo ship 500 GT and above- at least 02
  • Cargo ship 300 GT and above- at least 01
  • 1 on each survival craft

Battery Requirements of SART

  • In standby condition, operational for 96 hours
  • In working condition, operational for 08 hours
  • Battery should be replaced every 2 to 5 years
  • Operable in temperature between -20 deg to 55 deg

SART Testing Procedure

Self Test (General)

  • Switch SART to test mode
  • Hold SART in view of the radar antenna
  • Check that visual indicator light operates
  • Check that audible beeper operates
  • Observe radar display and see if there are concentric circles on the PPI
  • Check the battery expiry date

Self Test (Typical)

  • Remove SART from the bracket
  • Insert the probe into the SART at 2 seconds interval; the lamp flashes and the beeper sounds
  • Observe concentric circles on the X band radar

In case of a false activation, switch the SART off immediately. Transmit a DSC safety alert on VHF Channel 70. Transmit a safety broadcast by RT on VHF Channel 16 to all stations indicating your ID and position and that you wish to cancel your false alert which was transmitted in error.

Looking at the facts, one can determine that SARTs are a marvel of human engineering, making them significant equipments on the ship venturing out in deep oceans.

Search and Rescue Transponder (SART)

SOLAS Requirements Related to Carriage on Ships

All Cargo ship 500 GT and above- at least 02 SARTs and Cargo ship 300 to 500 GT – at least 01 SART. While all Passenger ships irrespective of GRT – at least 02 SARTs.

SART is a very important Life saving appliance onboard. It’s regular maintenance is critical to it’s functioning and eventually helping at the time of actual distress.

10 Facts about SART – Search and Rescue Transponder

Here are some facts about SART (Search and Rescue Radar Transponder):

  1. A SART is a radar-based emergency transponder that is used to locate a vessel or aircraft in distress.
  2. The SART works by reflecting a radar signal back to the receiver on the search and rescue aircraft or vessel. This allows the rescuers to locate the SART and, therefore, the distressed vessel or aircraft.
  3. SARTs are typically used in conjunction with other emergency signaling devices, such as EPIRBs (Emergency Position-Indicating Radio Beacons) and PLBs (Personal Locator Beacons), to increase the chances of rescue in the event of an emergency.
  4. SARTs are typically designed to be portable and easy to use, and can be activated manually or automatically in the event of an emergency.
  5. SARTs are required on all SOLAS (Safety of Life at Sea) vessels, which include most commercial ships and some larger pleasure craft.
  6. SARTs have a limited range, typically up to 10 nautical miles, and their effectiveness can be affected by factors such as weather conditions and the height of the search and rescue aircraft or vessel.
  7. SARTs have been credited with saving many lives in emergency situations at sea, and their use is considered an important part of maritime safety equipment.
  8. SARTs are designed to operate in a specific frequency band, typically in the 9 GHz range, which is reserved for marine radar use.
  9. SARTs can be deployed in a variety of ways, including being thrown overboard, attached to a life raft, or manually carried by a person in distress.
  10. SARTs are typically powered by a long-lasting battery, and some models are designed to automatically turn off after a certain period of time to conserve battery life.
Search and Rescue Transponder (SART)

Real life Rescue Missions Involving SART – News

There have been many rescues in which SART played a critical role in locating and rescuing people in distress. Here are a few examples:

  1. In 2015, a sailor participating in the Clipper Round the World Yacht Race fell overboard and was lost at sea for 90 minutes before his crewmates were able to locate him using a SART. The SART helped rescuers quickly pinpoint the location of the sailor and ultimately saved his life.
  2. In 2017, the crew of a cargo ship called the “MSC Ravenna” were rescued off the coast of Scotland after the ship began taking on water. The crew activated their SART, which helped rescue teams locate and rescue them in challenging conditions.
  3. In 2019, a group of five sailors were rescued from their sinking catamaran off the coast of Tonga after activating their SART. The SART helped rescuers locate the sailors in a remote area and ultimately saved their lives.

These are just a few examples of the many rescues in which SART has played a critical role in saving lives at sea. SART can be extremely helpful in search and rescue operations at sea for several reasons:

SARTs can help rescuers quickly locate a vessel or aircraft in distress, even in low visibility or adverse weather conditions. The SART’s radar reflection can be detected by search and rescue aircraft and vessels, enabling them to locate the distressed vessel or aircraft more easily and accurately.

SARTs transmit a distinctive signal that confirms the presence of a distress situation, which can help rescue teams differentiate between genuine emergencies and false alarms.

Have you seen a SART?


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