H O M E  | 
In 15 Seconds Your Rescue Will Begin...
Order Form
 Alerting Units SMRS-LR Man Overoard Alert SMRS-LD Lost Diver SMRS-MS Submariner SMRS-IS Industrial
 Base Units SARfinder 1003 (Fixed) CrewFinder RT-202 / 300 / 500 (Fixed) CrewGuard 121 (Portable)
 
What is a Maritime Survivor Locating Device?

A Maritime Survivor Locating Device is a Self Managed Man Overboard System
made up of one or more of the following components,  Alerting Units and Base Units:

ALERTING UNITS
A device worn by crew (Personal Locator Beacon) which communicates with a
receiver (Base Unit) to indicate when a Man Overboard incident has occurred. 
 
      
 

BASE UNIT
A receiver that continuously monitors for an ‘SOS’ signal from an 
Alerting Unit, this can be one of two options: 

Option 1
Man Overboard Alarm …Sea Marshall® Crewguard CG-121 MKII Man Overboard Alarm

 

 

Option 2
Man Overboard Locator …Sea Marshall® SARfidner® 1003 Man Overboard Locating Unit

           


 
The Sea Marshall® Man Overboard system is a self managed system designed to allow an operator to search for and locate their own crew in the event of a Man Overboard incident.

The Sea Marshall® PLBs transmit on 121.5MHz (this is Internationally recognised SAR homing frequency world-wide) giving the user the full support of their local Search And Rescue Authorities if they require outside assistance to locate a Man Overboard.

The Sea Marshall® system is not a satellite based system, it is a self managed system. 
 
The 121.5MHz satellite channel will be switched off in 2009, but this will not affect the Sea Marshall® system.

Why is 121.5 MHz the Only Frequency for Man Over Board Alert and Locate?

  • The minimum response time for a 406MHz beacon can be up to 90 minutes before a search is even initiated and this is totally dependant on the person carrying the unit being able to switch it on…a difficult task if you’re unconscious or in Cold Shock response!  

    •  
  • The minimum Alert time for a fully automatic Sea Marshall® 121.5 MHz PLB, to a boat fitted with a suitable alarm/receiver, is approx 15 seconds.  

    •  
  • 406 MHz PLBs are not fully automatic…useless if you are knocked unconscious. 

    •  
  • 406 MHz PLBs must be registered to each person and cannot be exchanged amongst crew members. 

    •  
  • Other systems transmitting on frequencies away from 121.5 MHz cannot be tracked by the Search and Rescue Authorites. Which means that if the person in the water floats out of range of the receiver on the boat then the chances of them being located are dramatically reduced…the search will become visual only which is like looking for a needle in a haystack. 

    •  
  • Proximity Alerting systems, working on frequencies away from the SAR homing frequency, carry the risk of a crew member falling over board and becoming trapped next to the vessel, in a line or net perhaps, and the alarm not being raised because the person has not gone out of the monitored area resulting in drowning. Also such systems are operating on frequencies that cannot be tracked by the Search And Rescue Authorities.
Sea Marshall® UK - based developers and designers of maritime survivor locating devices, from radio direction finders to lifejackets and offshore personal locator beacons (PLBs) UK based developers and designers of maritime survivor locating devices, from radio direction finders to lifejackets and offshore personal locator beacons (PLBs) radio direction finders, uk, lifejackets, personal locator beacons, plbs, maritime, survivor, personal, sar, man over board, mob, alerting, devices, alarms, offshore, emergency, location, transmitters, developers, designers.