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-   -   Would a PLB help if you went overboard? (https://www.sailnet.com/forums/gear-maintenance/55792-would-plb-help-if-you-went-overboard.html)

MedSailor 06-29-2009 10:51 PM

Would a PLB help if you went overboard?
 
Someone mentioned having a PLB on their person in case they went overboard as it would assist with rescue.

So would a PLB help at all this this situation? I understand they also emit 121.5MHZ signals for direction finding assistance to SAR but if you don't have a 121.5MHZ receiver it won't help the boat find you will it?

Seems to me like if you went over in the big blue the odds of a boat being close enough to find you (and the SAR folks routing said ship) before you were shark food are not good.

I ask because they are getting cheap. I know that the only real insurance is to stay the *&## on board but if there was a homing gadget that could assist I wouldn't turn it down.

MedSailor

brak 06-29-2009 10:59 PM

no PLB emits 121.5Mhz signal anymore.

in any case, response time to PLB is (many) hours, whereas someone overboard probably has a lot less, perhaps minutes depending on circumstances.

sailingdog 06-30-2009 06:33 AM

brak—

I don't know where you're getting your information, but it is WRONG. PLBs and EPIRBs transmit a SAR transponder signal on the 121.5 MHz band. It is used for directional location by SAR personnel.

From the ACR website, from one of their PLB pages:

Quote:

Transmits on 406 MHz via the COSPAS-SARSAT satellite system with your registered, unique, digitally coded distress signal and 121.5 MHz (SAR homing frequency).
I think you're confusing the fact that 121.5 MHz EPIRBs have been discontinued and thinking it means that EPIRBs and PLBs don't broadcast on 121.5 MHz... which they do.
Quote:

Originally Posted by brak (Post 501400)
no PLB emits 121.5Mhz signal anymore.

in any case, response time to PLB is (many) hours, whereas someone overboard probably has a lot less, perhaps minutes depending on circumstances.




brak 06-30-2009 09:14 AM

Ah, you are correct. Oh well - I still don't think PLB would do much if someone falls overboard - the timeframes are vastly different.

DwayneSpeer 06-30-2009 11:40 AM

Depends where you are.
 
PLBs would work well, I think, depending on where you are. They use a satellite that is centered over North America so don't reach out more than a few hundred miles into the Pacific and of course if you are very far out the cold water would probably do you in well before some found you in a SAR situation.

sailingdog 06-30-2009 12:56 PM

Quote:

Originally Posted by brak (Post 501518)
Ah, you are correct. Oh well - I still don't think PLB would do much if someone falls overboard - the timeframes are vastly different.

A PLB would work just fine in near tropical or tropical waters. Up north, like near New England, hypothermia is a factor...




Sarguy 06-30-2009 01:16 PM

Quote:

Originally Posted by DwayneSpeer (Post 501581)
PLBs would work well, I think, depending on where you are. They use a satellite that is centered over North America so don't reach out more than a few hundred miles into the Pacific and of course if you are very far out the cold water would probably do you in well before some found you in a SAR situation.

PLBs are received by the same Low Earth Orbit satellites that EPIRBS are picked up by, and they relay the signal to geostationary satellites, which relay to earth. The geostationary satellite does not directly receive signals from PLBs and EPIRBs. Coverage is pretty even worldwide between N70º and S70º, and pretty spotty closer to the poles. BothPLBs and EPIRBS transmit on 121.5MHZ at 25 milliwatts for short range direction finding. The 121.5 transmission is no longer received by the LEO satellites, as of February, 2009.

Valiente 06-30-2009 01:21 PM

PLBs are meant to assist SAR personnel to find you. EPIRBs are meant to assist SAR personnel to find your boat or your liferaft.

I think what you mean are "self-rescue" systems whereby you have a short-range locator beacon on which a shipboard direction finder can zero in:

Man Over Board Systems, MOB Rescue System, Self Managed Rescue System

The trouble is that these stand-alone systems are really expensive, and the situations in which a sailboat can effectively self-rescue a crew are typically few. Picture a cruising couple on a downwind run in a gale. A preventer line parts, the boom crash gybes, and the PFD-wearing...but untethered...husband is knocked in the head and right over the lifelines. The beacon is activated hydrostatically, and the husband's PFD also inflates.

Now you've got a guy in 20-foot waves with a head laceration, perhaps a cracked skull, very dazed or totally unconscious, in the water. He isn't sinking, but he isn't swimming, either, nor can he more than reflexively keep his head out of the water and the breaking spray, so he might drown in his PFD anyway.

The wife is hypothetically a great sailor in her own right, but she has to bring the boat around in a gale and sail or more likely motor directly into the wind in very challenging conditions.

Then what? Motoring in heavy seas next to an unconscious floater is a good way to kill him off entirely through blunt force on the hull or by beheading him with the prop. This is assuming you can even get close to keep him in sight...I hope that PFD has a strobe! Or that it isn't blackest night...

My point is that finding someone, even someone uninjured and conscious, is no guarantee of getting them aboard a sailboat in heavy weather. Few autopilots are going to work in such conditions, and the boat itself becomes very dangerous.

If the water temperature allows it and one is coastal, the odds are better to let SAR handle it, in my opinion, but I believe the best option is to tether on religiously in any situation in which you are unlikely to have another crew save you. That means "much of the time on passage", unless motoring through a calm.

Airbags didn't replace seatbelts, nor do they permit terrible driving. If you work from the baseline that falling off a moving boat is a potential death sentence in every instance, you may invest less in "spot the corpse" technologies and more in behaviour modification on deck.

fafnir 06-30-2009 05:08 PM

We call them "body beacons" on Lake Superior, the best thing to have in my opinion is a waterproof handheld VHF radio in the pocket of your life vest. Some flares are probably helpful as well.


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