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Old 27-06-2014, 05:07   #31
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Re: Handheld DSC VHF vs. PLB for MOB

Another case of a MOB casualty rescued as a result of a PLB distress signal:

BBC News - Powerboat owner plucked from sea off St Anne's Head

This guy was wearing a drysuit, but still -- was rescued within 3 hours, from the middle of the Irish Sea.
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Old 27-06-2014, 05:14   #32
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Re: Handheld DSC VHF vs. PLB for MOB

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Originally Posted by Dockhead View Post
Another case of a MOB casualty rescued as a result of a PLB distress signal:

BBC News - Powerboat owner plucked from sea off St Anne's Head

This guy was wearing a drysuit, but still -- was rescued within 3 hours, from the middle of the Irish Sea.

The key point being " dry suit "

Otherwise as I've said before PLBs are just body location systems

Dave
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Old 27-06-2014, 05:14   #33
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Re: Handheld DSC VHF vs. PLB for MOB

Here's the guy's own account of being rescued from the Irish Sea. A really harrowing tale!! And interesting: • View topic - Rib driver thrown out of boat
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Old 27-06-2014, 06:41   #34
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Re: Handheld DSC VHF vs. PLB for MOB

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The key point being " dry suit "

Otherwise as I've said before PLBs are just body location systems

Dave
I don't know. After doing some reading, I'm not sure I entirely agree with this as a categorical position any more. The first case, off Cornwall, was without any drysuit.

Here's another: An Ill-Fated Test Spin of a New Boat Ends in Disaster | Miami New Times

Warm water, but the casualties were rescued in almost exactly one hour after activating their PLB, from 15 miles out of Miami.

Most of the year, the water in the Channel is over 10 degrees C, and is typically over 15 degrees in the late summer/early fall. Most people will survive several hours in 15 degree water without a drysuit, and at least an hour or so, if not a couple of hours, in 10 degree water. If typical rescue times are one or two hours, then I think you have a pretty good chance of being rescued in coastal waters by PLB distress signal.

So I am no longer so convinced that PLBs are so useless for MOB cases.

But one thing which is surely correct is that a PLB is no substitute for some means of signalling which is received instantly by vessels in the immediate vicinity. I think an AIS Sart is probably the best option for this, although I would sure like to have a very compact DSC VHF handheld.
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Old 28-06-2014, 01:50   #35
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Re: Handheld DSC VHF vs. PLB for MOB

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Originally Posted by Dockhead View Post
I don't know. After doing some reading, I'm not sure I entirely agree with this as a categorical position any more. The first case, off Cornwall, was without any drysuit.



Here's another: An Ill-Fated Test Spin of a New Boat Ends in Disaster | Miami New Times



Warm water, but the casualties were rescued in almost exactly one hour after activating their PLB, from 15 miles out of Miami.



Most of the year, the water in the Channel is over 10 degrees C, and is typically over 15 degrees in the late summer/early fall. Most people will survive several hours in 15 degree water without a drysuit, and at least an hour or so, if not a couple of hours, in 10 degree water. If typical rescue times are one or two hours, then I think you have a pretty good chance of being rescued in coastal waters by PLB distress signal.



So I am no longer so convinced that PLBs are so useless for MOB cases.



But one thing which is surely correct is that a PLB is no substitute for some means of signalling which is received instantly by vessels in the immediate vicinity. I think an AIS Sart is probably the best option for this, although I would sure like to have a very compact DSC VHF handheld.

The RNLI stats for water survival around the UK coast is basically 30 minutes without some form of survival suit , after 30 minutes you are non responsible, after 1hour your dead

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Old 28-06-2014, 03:23   #36
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The RNLI stats for water survival around the UK coast is basically 30 minutes without some form of survival suit , after 30 minutes you are non responsible, after 1hour your dead

Dave

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At what temperature?

At 15 degrees, average survival time without special clothing is 6 hours, according to USCG.

Maybe in winter with 6 degree water some people will be dead after one hour.

In any case, survival varies enormously depending on body type, posture in the water, etc. a fattish guy who knows how to float in a heat conserving position will survive double or triple longer than a slender, panicked female. Obviously sea conditions matter a lot too.

So I don't think you can make such a blanket statement. I conclude from this reading that in summer and fall in UK waters you have an excellent chance of being rescued by PLB. In winter, or in really rough weather, your chances are much, much less, but probably still a lot more than nil, and maybe even more than even.

Which leads me to conclude that it is very, very worthwhile to have a PLB on your person, at least as Plan B.
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Old 28-06-2014, 15:58   #37
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Re: Handheld DSC VHF vs. PLB for MOB

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At what temperature?

At 15 degrees, average survival time without special clothing is 6 hours, according to USCG.

Maybe in winter with 6 degree water some people will be dead after one hour.

In any case, survival varies enormously depending on body type, posture in the water, etc. a fattish guy who knows how to float in a heat conserving position will survive double or triple longer than a slender, panicked female. Obviously sea conditions matter a lot too.

So I don't think you can make such a blanket statement. I conclude from this reading that in summer and fall in UK waters you have an excellent chance of being rescued by PLB. In winter, or in really rough weather, your chances are much, much less, but probably still a lot more than nil, and maybe even more than even.

Which leads me to conclude that it is very, very worthwhile to have a PLB on your person, at least as Plan B.

Sorry yes at 5 degrees worst case.

Actually the authority on the matter is the UKNiis immersion study, which the USCG reports defers to

It's summary is


Accepting the above limitations, 50% survival times for normally clothed, young, fit and healthy individuals approximate: 1 h in 5C (41F) water; 2 h in 10C (50F); and 6 h in 15C (59F).
"

50% survival being in effect out every 100 people 50 would still be dead at these limits

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Old 28-06-2014, 19:42   #38
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Re: Handheld DSC VHF vs. PLB for MOB

Sorry to drift this thread back to the original topic/premise....but...

But, does anyone know if "SailFastTri" (the original poster) or "Gamayum" (the other poster under the false impression that vhf-dsc radios will relay a dsc-distress call), have actually read/understood the facts presented here??

Have they understood that DSC-Distress calls are NOT automatically relayed to other vessels / shore stations??
Neither of them have been heard here in 2 weeks!!


Wondering if a PM to either, or both, would be a good idea??
(Anyone care to weigh in?)



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