Personal distress beacons: what are their interests? How do they work?

Personal distress beacons: what are their interests? How do they work?

A complete overview of a small product that could save your life

In case of distress at sea, on land or in the mountains, the first reflex is to use your mobile phone. However, and this is often forgotten, the use of mobile phones is not always possible (no network available, phone unloaded, man overboard,...). The emergency beacon then becomes the essential equipment to increase its chances of survival and benefit from fast and effective rescue.

There are two main families of personal emergency beacons, which operate very differently:

1) those using satellite networks, either free (such as Cospas-Sarsat) or subscription-based (such as Iridium, Globalstar/Spot, etc.)
2) those using "short-range" radio waves, 5 to 10 nautical miles (such as AIS, marine VHF, etc.)

For use at sea, whether you are an occasional yachtsman or a professional (fisherman), two types of beacons are interesting:


These beacons use the Cospas-Sarsat satellite network. The coverage is worldwide and their use does not require any subscription. EPIRBs are quite cumbersome but can float. They transmit for a minimum of 48 hours. EPIRBs are mandatory on all professional vessels, regardless of size. They are also mandatory for boaters in the event of offshore navigation (more than 60 miles from the coast). In the event of a shipwreck, the EPIRB can be activated automatically and is released from the boat to transmit distress even if your ship has sunk.
If you are sailing far from the coast, the EPIRB is an essential safety element.

Once triggered, an EPIRB sends a first signal (406 MHz) to the Cospas-Sarsat satellites and another signal (121.5 MHz) that will help locate you when help arrives in the area (by helicopter, rescue shuttle, etc.). The detection time of a Cospas-Sarsat beacon is very fast if it incorporates a GPS chip. Attention, EPIRBs must be registered. Registration is important because if your EPIRB is triggered, the rescuers will know what type of boat you are, the number of passengers, the call numbers to dial to clear up any doubts about false alarms, etc...

The Advantages of EPIRBs :

- Global satellite coverage, no subscription, free backup

- Near instant detection if the beacon incorporates a GPS chip (mandatory for EPIRBs)

The disadvantages of EPIRBs:

- Large size (impossible to carry it with you)

- Very high price (between 400€ and 800€ depending on the models)

*AIS (Man Overboard) personal beacons

These beacons are very interesting because they are very compact and lightweight like SIMY's My-AIS model. They do not require a subscription and can be attached to the lifejacket without restricting movement. These beacons have a fixing clip for the buccal tip of the vest - this makes assembly easier. Once activated, the beacon transmits the shipwrecked person's GPS position on the AIS network as well as a standard distress message.

The AIS network

At sea, ships exchange data on their positions, speeds, headings, etc. in order to avoid collisions. AIS provides immediate visibility of the position of nearby vessels.

Ships equipped with AIS transceivers are now very numerous and growing. All professional vessels have them, but also a large number of yachtsmen. From 1 January 2017, fixed VHF on board becomes mandatory for all vessels sailing more than 6 miles from the coast. It is then interesting to opt for a DSC-compatible VHF (this type of VHF is compatible with AIS). Simply connected to a GPS, this VHF DSC will display the positions of the ships around you via a map reader.

If an AIS beacon is activated near ships equipped with AIS, they will then receive a "Man OverBoard" alert. The GPS position of the shipwrecked vessel will be displayed on the AIS receiver and the nearest vessels will be able to divert to provide immediate assistance.

If you fall into the water and your ship is equipped with AIS, then the AIS will sound and the other crew members on the ship can immediately respond. You can also see the importance of the maritime community equipped with AIS by visiting You will find a map of AIS vessels in real time.

carte des navires ais en temps réel

AIS distress beacons are based on solidarity at sea. The entire community of sailors in the vicinity will be able to assist the user in case of danger. AIS distress beacons allow a quick response from surrounding vessels within radio range.

Personal AIS type beacons seem to be an ideal compromise for coastal boating and interesting also for mid-shore navigation. For more information on SIMY's My-AIS beacon (battery life, mounting in the vest, activation of the beacon, etc...) you can contact us by e-mail at:

*Beacons with subscription (Spot, Globalstar, Iridium...)

These beacons use paid satellite networks (Globalstar, Spot, Iridium...). Their services are complemented by tracking, help request and SMS messaging functions. They all include a GPS chip to transmit the position.

Apart from the cost of the beacon, the prices can be high, around 15 to 20€ per month. See below for an example of a rate with the SPOT beacon.

tarif des abonnements des balises   SPOT-GEN3

Created On  25 Aug 2017 15:58  -  Permalink


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