How Mobilarm Man Overboard Alarm Systems Work

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Mobilarm man overboard alarm systems provide automatic, immediate alert and GPS track back data to crew in a man overboard emergency. The fundamental principle behind the system is that crew members are always connected to the vessel via a wireless network which continuously monitors their presence, and therefore safety, on board.

Safe on board

Man overboard! MOB track back screen 
Each crew member wears a compact and lightweight transmitter - a tag or pendant - which is individually registered to the wireless network onboard the vessel.

The tag continuously transmits a signal to the system's control panel (coordinator). When the control panel receives the tag signal, it recognises that the crew memeber is connected and therefor deems that person 'safe'.

If the tag is submersed in water (goes overboard) or moves too far from the network, the signal fails to reach the control panel and so the system automatically raises an audible and visual alarm.

The design of Mobilarm systems is fail-safe; even a damaged tag or one with a flat battery breaks the connection to the network and sounds the alarm, alerting crew to a potential safety emergency. 

The system is ‘always on watch’ and will safeguard crew from going overboard unnoticed.

Timing is everything. Within three seconds of a crew member going overboard, the system will automatically log a waypoint. It sounds the alarm just four seconds later if connection by the tag is not re-established (so the occasional rogue wave over the deck will not inadvertently set off the alarm).

The vessel’s own plotter or GPS will provide crew with essential track back information to the waypoint, enabling a quick and effective rescue of the missing crew member. If the need arises, multiple MOB events can be tracked simultaneously.

 Use way point to MOB Rescue MOB Everyone safe on board
Other emergency marine safety equipment such as a 406MHz PLB (Personal Locator Beacon) must be manually activated by the person in distress.

Mobilarm man overboard alarm systems are fully automatic and require no manual intervention to raise the alarm, essential if the person is incapacitated as they go overboard. 		Another advantage over PLBs is that the Mobilarm distress alarm is raised directly on the vessel the MOB came from, and which is closest to the casualty.

In contrast, a PLB distress signals is transmitted to land-based search and rescue services which can add precious minutes, possibly hours to the length of time the casualty is in the water before recovery.

With Mobilarm, any man overboard can be safely back on deck in a matter of minutes.

Once the crew member,wearing his tag, has been recovered and is back aboard the vessel, the Mobilarm system cancels the alarm and resumes its role of monitoring the safety of the crew.

 

Disclaimer:
No system can be 100% fail-safe. Installation faults and operator error will always introduce the possibility of undetected man overboard (MOB) events, as can circumstances and events beyond the equipment's design criteria.

Mobilarm man overboard alarm systems should never be relied on as the only source of MOB notification or response. The vessel's captain and crew must exercise prudence, common sense and good seamanship. Installation and operation of a Mobilarm man overboard alarm system in no way reduces the responsibility of the captain and crew who have the primary responsibility for safety on board the vessel.