An EPIRB, a satellite-linked beacon, is a crucial piece of survival equipment for any vessel. Activated in emergencies, it transmits a distress signal to rescue services, providing critical location data.
On the other hand, a SART is a radar-based device used specifically for locating life rafts or survivors in the water. Together, these beacons form a robust safety net, increasing the chances of a successful rescue.
Emergency Position-Indicating Radio Beacons
The essential purpose of an EPIRB signal is to help determine the position of survivors during SAR operations.
The EPIRB signal indicate that one or more persons are in distress, that they may no longer be on board a ship or aircraft and that receiving facilites may no longer be available.
A cost station (i. e. Local User Terminal) receving an EPIRB transmission would consider that the vessel in distress is unable to transmit a distress message and so a Mayday Relay would normally be transmitted to ship in the area by any suitable means, e. g.:
- Inmarsat,
- DSC,
- NAVTEX.
All EPIRB should have arrangements for a local manual activation or float-free release and self activation. Remote activation from the navigating bridge, while the EPIRB is installed in the float-free mounting, may also be provided. The equipment, mounting and releasing arrangements should be reliable, and should operate satisfactorily under the most extreme conditions likley to be met at sea. Manula distress alert initiation should require at least two independent actions.
All types of EPIRBs should also be equipped with a light of 0,75 candela, flashing with a low duty-cycle ratio, which is automatically activated by the onset of darkness.
COSPAS-SARSAT EPIRBs
This EPIRB system uses low-altitude polar-orbitoring satellites operating on 406 Mhz. The transmissions are recevied by the satellites, which pass on the relevant information to a Local User Terminal (LUT), which then passes information to rescue authorities via a Mission Control Centre (MCC).
The position of the EPIRB can be found by the satellite using Doppler frequency- shift measurement techniques. However, some 406 Mhz EPIRBs transmit digitally coded information, including:
- ship indentification;
- date;
- country of origin;
- nature of distress;
- and (if interfaced with, for exemple, a GPS receiver) the position.
A 121,5 Mhz signalling facility is included on all current production COSPAS-SARSAT EPIRBs which serves primarily to provide a homing signal for aircraft.
VHF DSC EPIRBs
The VHF EPIRB is intended for use in A1 sea areas and operate by transmitting a DSC distress alerting signal on the frequency 156,525 Mhz (channel 70).
Some VHF DSC EPIRBs also incorporate a 9 Ghz radar transponder for the purpose of providing a locatng signal.
Registration, Care, Use And Disposal
Masters must ensure that their EPIRBs have been registered with the relevant authority in the flag State, enabiling details to be available to SAR authrities when requested.
EPIRBs should be installend so that they cannot be tampered with or accindentally activated. EPIRBs are equipped with a buoyant lanyard suitable for use as a tether in order to secure the beacon to a liferaft, boat or person in the water.
The EPIRB should not be activated if SAR units are already on-scene. If previously activated, it should be switched off when rescue units arrive.
Damaged EPIRBs or those on a ship going for scrap should be made inoperable. Remove the battery before demolition or before returning it to manufacture for re-programming. On-vessels being sold to new owners, the EPIRB must be re-registered
EPIRB Test Procedure
EPIRBs should be tested on a regular basis as follows:
Press and release test button
- Red lamp should flash once;
- Within 30 seconds the strobe and red lamp should flash several times
- After 60 seconds the EPIRB swirches off EPIRBs incorporate the means tocarry out regular tests (without access to the space segment) and indicate the emission of a distress alert of any fault in the equipment.
Fals Alerts
If an EPIRB is accindentally activated, the nearest coast station or an appropriate coasts earth station or RCC MUST be informed immediately that a false distress alert has been transmitted and should be cancelled. Details of RCCs are to be found in the ITU List of Coast Stations and various publications produced by national Administrations and service providers.
Search and Rescue Radar Transponders – SARTs
These are used to home SAR units to the positions of a person in distress. They operate on the 9 Ghz band and only transmit, assuming they are switched on, when interrogated by another radar.
The SAR should operate correctly when triggered by another vessel’s radar at distances of up to at least 5 nautical miles. Detection at longer ranges will be achieved from aircraft; at 3 000 ft, for example, the aircraft radar should elicit a useful response up to 30 nautical miles away from the SART.
Read also: NON-DSC Terrestrial Distress Communications
The transmission produces a distinctive line on radar display of about 12 blips extending out from the location of the SART along the line of bearing. These change to concentric circles when the SAR unit reaches to within about 1 mile of the SART.
To ensure that the SART transmissionwill be receivable over a useful distance it is essential that the SART be mounted as high as possible. The ineffectiveness of poorly mounted SARTs in survival craft and liferafts has been demonstrated repeatedly in exercises. In order to maximise the range, the regulations require a mounting height of at least 1 metre above sea level.
The SART paint on the radar display may be more easily identified, especially if clutter or many other targetsare present, by detuning the SAR unit’s radar. Detuning reduces the intensity of return echoes on the display but allows the SART signal to be seen more easily since the SART emits a broad-band signal which detuning does not affect to the same degree.
SART Test Procedure
SARTs should be tested on a regular basis as follows:
- Switch SART to test mode;
- Hold SART in view of radar antenna;
- Check that visual indicator light operates;
- Check that audible beeper operates;
- Observe radar display – concentric circles should be displayed;
- Check battery expiry date.
- General operator’s Certificate for The Global Maritime Distress and Safety System, Course + Compendium, Model Course IMO 1.25, Printed by PMS UK Ltd London, 2004.
- European Radiocommunications Committee ERC Decision of 10 March 1999 on the harmonised examination syllabi for General Operator’s Certificate (GOC) and Restricted Operator’s Certificate (ROC)(ERC 99 01).
- IMO GMDSS-Handbook, London, U. K., 2004.
- Norcontrol Capella GMDSS Simulator, Technical documentations, Kongsberg Maritime Ship Systems, Norway, 2005.
- INMARSAT MARITIME COMMUNICATIONS HANDBOOK – INMARSAT – London, U. K., 2005.
- Seafarers’ Training, Certification and Watchkeeping CODE 1995 (STCW Code 95, published by IMO, London, 1996), – Part A Mandatory standards regarding provisions of the annex to the Convention Chapter IV Standards regarding radio personnel.
- Seafarers’ Training, Certification and Watchkeeping CODE 1995 (STCW Code 95, published by IMO, London, 1996), – Part B Mandatory guidance regarding provisions of the STCW and its annex; Chapter IV Guidance regarding radiocommunication and radio personnel.
- V. Pipirigeanu, M. Udrea, Introducere in GMDSS – Sistemul Mondial de Primejdie si Siguranta Maritima, Ed. Europolis, Constanta, 2002.
- Graham D. Lees, William G. Williamson, Handbook for Marine Radio Comunication, e d. LLOYD S OF LONDON PRESSLTD., 2004.
- ITU Manual for Use by The Maritime Mobile and Maritime Mobile Satellite Services, 2006.
- IAMSAR Manual – International Aeronautical and Maritime Search and Rescue Manual, 2001.
- C/S G.003 – Introduction to Cospas-Sarsat System, (G3OCT28.99D Issue 5 – Rev. 1 October 1999), C/S Documents published by Cospas-Sarsat in Handbook of Regulations on 406 MHz and 121,5 MHz Beacons, (1999);
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- C/S T.001 – Specification for Cospas-Sarsat 406 MHz Distress Beacon, (T1OCT30.99D – Issue 3 – Rev. 2 October 1999), Documents published by Cospas-Sarsat in Handbook of Regulations on 406 MHz and 121,5 MHz Beacons (1999).
- IMO SOLAS (SAVE OF LIVE AT SEA), Consolidated Edition, London, 2001.
