Draft
12
DOC-0132 Crewsafe User Manual v.1.2
Mobilarm Ltd. © 2009
4.1
How it Works
1. Onboard monitoring is provided by each crew member wearing a robust, compact and
lightweight Tag, which is individually registered to a reliable and dependable wireless
network installed on the boat. Tags continuously transmit a ‘safe’ signal to the network,
which consists of one or more wireless routers ‘meshed’ together to provide a
wireless onboard monitoring system. A Display Console displays the status of all
Tags on a vessel at all times.
2. A Tag is unable to transmit through water and an alarm is automatically triggered if a
person falls off a vessel and a Tag’s connection to the network is broken. This may be
the result of a flat battery, a Tag going out of range or being damaged - or a man
overboard event. This provides peace of mind that the system is working properly at all
times and won’t let you down should you come to rely on it in an emergency*.
3. Within four seconds of a person going overboard and their Tag being disconnected
from the network, the system automatically logs a waypoint. The Display Console can
send this waypoint to a NMEA 0183 compatible chart plotter or GPS. If connected, the
boat’s chart plotter or GPS can display essential track back information to the man
overboard waypoint to enable a quick and effective rescue. Multiple man overboard
events can be tracked simultaneously.
4. A man overboard alarm sounds four seconds later if a Tag’s signal is not re-
established. (This ensures that the occasional rogue wave washing over the deck
does not inadvertently set off the alarm.) Unlike some other Personal Locator Beacons
and Emergency Position Indicating Radio Beacons (EPIRBs), Crewsafe Tags
automatically activate an alarm. This is important in the event that a person is knocked
unconscious, incapacitated or incapable of activating an alarm when they go
overboard. When an alarm sounds all Tags connected to the network vibrate and flash
and all internal and external routers flash. The Display Console and any other Internal
Routers also sound an audible alarm.
5. The other benefit of all Mobilarm man overboard systems over other Personal Locator
Beacons is the immediate notification to crew on a vessel of a man overboard
emergency as soon as it occurs. EPIRB signals, for example, are routed to onshore
locations and these distress signals need to be confirmed before the information is
then relayed to vessels in the vicinity. This can add precious minutes or hours to the
length of time a man overboard is in the water before a rescue is initiated.
6. With Crewsafe, after a man overboard has been recovered and is back onboard the
vessel, the system automatically detects the signal from the retrieved mariner’s Tag.
This automatically cancels the alarm and the system resumes normal operation.
7. A duress alarm can be manually triggered by a person pressing and holding the button
on a Tag for 3 seconds. The Tag sending an alarm is identified on the Display Console
and a system-wide alert is sent to warn that this crew member is in distress. Duress
alarms provide the ability for a crew member to manually initiate an alarm if they are in
distress for some reason.
8. A general alarm can be initiated by pressing the alarm button on the Display Console
