Submerged EPIRB

[Noddy]

Will an EPIRB work underwater.

In the unlikely event of a capsize with the EPIRB still inside. The moisture will trigger it but will the signal get out from under about 1 meter of water and some GRP??

 

[lw395]

No!
Or at least the signal will be very, very weak., if the epirb is underwater, however if its in the air space in the cabin, it will probably radiate fairly effectively through the bottom of the hull. But then it won't have turned on automatically.

 

[Noddy]

I don't feel any better but Thanks!

Have to take it with me then!

 

[yindoor2]

Always take it with you . If you dont the rescue services will be searching where the epirb was located and not where you could have drifted off to.

 

[Talbot]

Old EPIRB designs allowed the aerial connection too close to the water. They worked well in tank tests but during a US boat mag test in real conditions it was discovered that this proximity to the water allowed a considerbale amount of the transmission power to be leeched across this small gap and thus into the water rather than into the air - result no discernable signal to the satellite. McMurdo were the worst and they did a re-design.

Salt water is a conductor and will happily absorb power, this after all is the principle behind the SSB ground plane. therefore an EPIRB radiating with even a part of the aerial immersed is going to be ineffective. I would guess that an epirb operation in very high sea states with a lot of driven spray would probably suffer the same problem, so would keep the epirb inside the liferaft in those conditions, or possibly even wait until conditions had calmed down somewhat.

 

[Jacobs]

A PLB or Personal EPIRB must be held clear of the water to operate efficiently. Full size EPIRBs are designed to work best when floating using the water 'ground' to boost performance.

 

[Talbot]

I suggest you read the report on the trial before making statements like that. furthermore the frequency used by satellites is a very short wave length which does not use ground plane for aerial tuning.

 

[Talbot]

I have refered in an earlier message to the BoatUS tests abt 6 years ago which found a significant problem with some of the designs. McMurdo fared very badly in those tests, but they very quickly re-designed their equipment and are as good as any today. There is a report on a series of trials (carried out by McMudo) which probably answers your questions as well as any other I have seen. There is a copy available at http://www.equipped.org/McMurdo%20406%20MHz%20Beacons%20Test%20Report%20HiRes.pdf