Search and Rescue Transponder (SART): A Comprehensive Guide

 

Introduction: The Crucial Role of SARTs in Maritime Safety

 

In maritime emergencies, quickly and accurately locating survivors is paramount. This is where the Search and Rescue Transponder (SART) plays a critical role. A SART is a self-contained, waterproof device designed to assist in locating survivors during search and rescue (SAR) operations. When activated, a SART emits a signal that is detected by radar or AIS equipment on nearby vessels and search aircraft, allowing rescuers to pinpoint the location of the distressed vessel or survivors in life rafts. This article will provide a comprehensive overview of SARTs, covering their types, operation, installation, maintenance, and regulatory requirements.

 

Types of SARTs: Radar SART and AIS SART

 

There are two main types of SARTs:

• Radar SART (Search and Rescue Radar Transponder): This is the traditional type of SART, designed to be detected by X-band (3 cm) radar on ships and aircraft. 
• AIS SART (Automatic Identification System Search and Rescue Transmitter): This newer type of SART transmits a signal that is detected by AIS receivers, providing more precise location information and faster detection compared to radar SARTs. 

While both types serve the same primary purpose, they operate using different technologies and offer distinct advantages. Since 2010, per SOLAS regulations, either a radar SART or an AIS SART can be carried to meet the requirements.

 

How SARTs Work: Principles, Frequencies, and Range

 

• Radar SART:

  • Working Principle: When a Radar SART receives a radar pulse from a nearby ship or aircraft’s X-band radar, it automatically transmits a series of twelve equally spaced dots on the radar display. As the searching vessel gets closer, these dots turn into arcs and eventually concentric circles, pinpointing the SART's location.
  • Frequency: Operates in the 9.2-9.5 GHz (X-band) marine radar frequency range. 
  • Range: Typically, a radar SART can be detected by a ship’s radar at a range of up to 15 nautical miles, and by aircraft radar at much greater distances, depending on the aircraft's altitude.
     

• AIS SART:

  • Working Principle: An AIS SART, when activated, transmits a standard AIS safety message containing the SART's unique Maritime Mobile Service Identity (MMSI) number, GPS position, and other relevant information. This message is received by any AIS-equipped vessel or shore station within range. 
  • Frequency: Transmits on the marine VHF AIS frequencies (161.975 MHz and 162.025 MHz). 
  • Range: The range of an AIS SART is generally less than a radar SART, typically around 5-10 nautical miles, but it offers the advantage of immediate identification and precise GPS location.

 

SART Installation

 

Proper installation is crucial for the effective operation of a SART:

• Location: The SART should be stored in an easily accessible location, preferably near the bridge or in a survival craft. It should be protected from damage but readily deployable in an emergency.
• Mounting: The SART should be mounted securely to prevent it from being dislodged during rough conditions. For life raft deployment, it must be easily and quickly transferred.
• Activation: SARTs are designed for easy activation, usually by a simple switch or lanyard pull.

 

SART Maintenance, Storage, Testing, and Battery Life

 

Regular maintenance is essential to ensure the SART is ready for use in an emergency:

• Storage: Store the SART in a dry, cool place, protected from extreme temperatures and direct sunlight.
• Testing: Regularly test the SART according to the manufacturer's instructions. This usually involves a self-test function that checks the battery and transmitter.
• Battery Life and Replacement: SARTs are equipped with batteries that have a limited lifespan. Check the expiry date on the battery and replace it before it expires. Typically, batteries have a lifespan of 5 years. Replace the battery according to the manufacturer's instructions. 
• Annual Shore-Based Maintenance: Some regulations require professional annual shore-based maintenance.

 

SART Carriage Requirements

 

The International Convention for the Safety of Life at Sea (SOLAS) mandates the carriage of SARTs on certain types of vessels:

 

Vessel Type	Number of SARTs Required
Passenger ships	2
Cargo ships of 500 gross tonnage and upwards	2
Cargo ships of between 300 and 500 gross tonnage	1

 

These regulations ensure that vessels have the necessary equipment to assist in SAR operations.

 

Conclusion

 

SARTs are vital safety devices that play a crucial role in maritime search and rescue. Understanding their function, operation, and maintenance is essential for all seafarers. Both Radar and AIS SARTs are effective means of alerting rescue services to your location in an emergency. HZH Marine offers a range of reliable SART solutions to meet various maritime needs. Contact us to learn more about our SART products and how they can enhance your vessel's safety.