Some Frequently Asked Questions about Man Overboard Systems

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What is the difference between a Sea Marshall® Alert & Locating System and a proximity Man Overboard Alert device?

With a Proximity MOB Alert system all you get when an Man Overboard incident occurs is the GPS position of the boat at the time the incident occurred, with the Sea Marshall Self Managed Man Overboard Alert & Locate System not only do you get an immediate warning of a Man Overboard you also have the ability to track and rescue the Man Overboard at day or night time. With the Sea Marshall® systems because the MOB Alerting Units (PLBs) transmit on the International recognised Search And Rescue homing frequency of 121.5MHz if you decide you need extra assistance to locate your missing crew member or members you can radio the local Coast Guard and ask for their assistance they will be able to track the ‘SOS’ signal from the Sea Marshall® Alerting Unit from their own SAR vehicles.

Further disadvantages of Proximity Alert Systems:

• Proximity Alert MOB systems use pendants which require recharging for lengthy periods of time at very short intervals.
• Proximity Alert MOB systems can only be used on smaller vessels.
• Should a crew member fall overboard and become tapped next to the boat in a line or net than the Alarm will not be activated because you are still within the proximity field.
• Cannot give exact Location/Direction of Man Overboard in the water.
• Cannot be Located or tracked by Search & Rescue Services.

Some people have told me that 406MHz beacons are better for Self Managed Man Overboard Alerting is this true?

No, 406 MHz are satellite based beacons. There are some 406 MHz Personal Locator Beacons available on the market but these are designed mainly for land use. 406 MHz PLBs are not fully automatic which means that if you fell overboard and were knocked unconscious or the water was so-cold that you could not use your arms and fingers properly from cold shock response then you would be unable to activate and deploy your 406MHz PLB. Another big disadvantage of 406 MHz in the context of Man Overboard Rapid Alert & Locate is that because they are satellite based it can take up to 90 minutes for a signal to be received by a satellite and forwarded to a ground station and number of more hours before any Search & Rescue vehicles could have even been launched by which time the person in the water could be in real trouble. In the context of Man Overboard Survival time is of the essence which is why a Self Managed Search & Locate System using the Search And Rescue Homing Frequency of 121.5 MHz is essential.