Signalling additions
The Fastfind PLB from McMurdo
There has been another part to this ongoing technological safety revolution. Some lifejackets now come with the ability to have a safety signalling device inserted or attached.
There are two types of Personal Location Beacon (PLB) signal, one of which operates on the 406mHz frequency and this will reach out to satellites and from there the coastguard. The other works on a 121.5mHz channel, and is a more local homing signal, able to reach helicopters or rescue boats in line of sight, and very useful for pinpointing the location of a man overboard. Most, like McMurdo’s Fastfind, combine the two signals into one unit, giving the best of both worlds.
But Paul White of Navimo explains that in his estimation, although you can buy a unit without a Global Positioning System, it is worth the extra money spent on GPS to narrow down the field of search from around 2.5 square miles to around 10 square metres.
Another point is made by Mr Lewin about the fit between PLBs and the lifejacket body. “You should have the antennae in the right position for the best chance of a good signal,” he explains. So, how the lifejacket holds the PLB is also important as it is best to keep the antennae as clear of the water as possible. To complete the rescue package, the system can be used with an on-board receiver and direction tracker, so that as soon as there is a casualty, the position can be tracked back as quickly as possible.
However, there is the argument that you need an Emergency Position Indicating Radio Beacon (EPIRB) on the boat ‘no matter what’ says Ocean Signal’s Alan Wrigley.
Like the PLBs they transmit on the 406 MHz and 121.5 MHz frequencies, but they are specifically designed to operate at sea and although they are a little larger than the PLBs, the flashing strobe works continuously and they also have a much longer signal life and are automatically activated on contact with water .
‘The length of time the signal can stay live is a critical factor’ says Mr Wrigley. SafeSea EPIRBs have focused especially on this point, and both careful design and highly efficient transmitter circuits mean that the LB2E battery has enough capacity to operate the EPIRB continuously, typically for four whole days, even while using the GPS fix.
‘You also have the option of an automatic release from the boat if it sinks, otherwise you have to be able to take the EPIRB with you when evacuating the boat or if in danger onboard – and although it’s mandatory for commercial boats there is an associated cost’, explains Mr Wrigley.
Again, with some EPIRBs, there is the possibility of an optional GPS – and the extra money is definitely worth it according to Mr Wrigley, as it not only improves location accuracy, but also significantly reduces the time taken for the position to be transmitted to the rescue authorities.
But, he points out one thing helps to reduce the costs of ownership is the batteries, as these can be replaced by the user, so the unit doesn’t need to be returned the unit to the agent or manufacturer.
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