AIS versus PLB - a dumb question

[Wotname]

Originally Posted by a64pilot

Did a quick Google, even Worst Marine carries them and I’ll likely go to them
Don’t usually give them much business but if they’ll bring one into the store for us to look at and try on, I think I will.

FWIW, I found mine to be very comfortable for long term wearing and even fairly good to sleep in without having to be dog tired first. The light on the pole or wand seems a worthwhile innovation. Like DH said, I suspect the included rescue knife might be hard to deploy in an emergency but I suppose it is better to have than not.

My local shop didn't have a great range of other high end PFDs to chose from so the Spinlock did stand head and shoulders above their other stock however I did try the following exercise.

Take each PFD on and off a few times, then look at other stuff in the shop for 20 or so minutes and then ask the guy to hand me a PFD while I kept my eyes shut. I then put each PFD on while keeping my eyes shut. By far the easiest was (in my case) the Spinlock. This was supposed to simulate trying to get a PFD on at zero dark thirty from fast asleep. I dunno the value of the exercise but it did give me confidence that wasn't hard to get the PFD on in a hurry.

[a64pilot]

I understand, and of course you understand why I want her to try it in before we buy.
Current ones we bought used and didn’t see them prior to. They would work I assume, but everything has been jury rigged on, the little light I think is probably worthless, and the AIS has to be manually deployed, a two step process, basically have to first remove the safety, then set it off, it’s not automatic, and I think it would be better if it were.
Plus I’m not so sure it would hold your head up, many don’t do that very well.
Ideal I think is one that if you got knocked silly and went overboard, it will automatically inflate, roll you over and hold you head out of the water, self deploy the light and AIS, requiring nothing from the wearer

[Wotname]

Originally Posted by a64pilot

I understand, and of course you understand why I want her to try it in before we buy.
Current ones we bought used and didn’t see them prior to. They would work I assume, but everything has been jury rigged on, the little light I think is probably worthless, and the AIS has to be manually deployed, a two step process, basically have to first remove the safety, then set it off, it’s not automatic, and I think it would be better if it were......

Yes, I concur and IMO, it would be foolish to spend big dollars on a high end PFD if it doesn't fit or is uncomfortable and one only knows that by trying it on in the shop before purchase as you quite rightly post.

What fits comfortably for me doesn't mean it fits comfortably for someone else!

IMO, a proper PFD must have leg (or at least crotch) straps and spray hood - essential in rough water IMO.

Originally Posted by a64pilot

......
Ideal I think is one that if you got knocked silly and went overboard, it will automatically inflate, roll you over and hold you head out of the water, self deploy the light and AIS, requiring nothing from the wearer

FWIW as a data point, the spinlock (when fitted with the rescueME AIS MOB1) does all that. I assume there must be other quality PFDs that do it also.

[Paul L]

The MOB1 ais/dsc sart fits inside my Crewsaver vest for auto launch

[CarlF]

The AIS MOB is really a game changer. When one went off accidentally in Camden Maine harbor inside a boat (belonging to Panbo who was testing a bunch of them) it set off the alarm on my chartplotter 13 miles away in Vinalhaven with a chartplotter icon right in the harbor. I'm sure over 100 boats got that alarm - including the CG (who showed up on ch 16 right away trying to confirm it).

As said, the only thing a PLB is good for is recovering they body. Due to the outdated 1960's technology of EPIRBS/PLB's it takes about 20 minutes for the signal to even get to the CG. In Maine, that's already too long.

While I have two PDF's with AIS MOB's, I've also constructed a throwable using a belt pack automatic inflatable PDF with an AIS MOB slipped inside. You throw it and it inflates turning on the AIS and starting a strobe. The risk is that the antenna won't be clear of the water after inflation but I tried it twice and each time the antenna landed right side up (I disconnected the trigger to avoid a false alarm). In most cases, I'm assuming the person will swim over to it and put it on.

There's also a company making a throwable AIS MOB that looks like a buoy.

[svtickles]

Originally Posted by Zzmeyer

Thanks for all the great comments. Perhaps a dumb conclusion I draw: There is no real value in having a PLB. They are not very useful in live recovery (at sea). Several mentioned the good idea of having one in or for the liferaft, but if I'm having a second I'll spend a couple hundred bucks more getting a second EPIRB. Because I already have a satphone and inreach I think I'll stick with a single EPIRB. For years I've had the question but was afraid to ask because it seemed there must be a simple answer as to why they sell "Personal Locator Beacons". That implied to me crew recovery, not body recovery.

Is this what you have?
https://www.garmin.com/en-IE/p/888769/pn/010-02602-30

[MC2019]

wrong PLB is an EPIRB with less battery life than a ship board
EPIRB.

Originally Posted by grantmc

You're not missing anything. Both EPIRBs and PLBs are 'requests for help' to the local Search & Rescue authority. That's their function and purpose. S&R (Coastguard in US I think) have people ready and waiting for the call. No different than Police, Fire and Ambulances.

PLBs are NOT personal EPIRBs.

I'd add when someone falls overboard that's a very serious event, and if it were me in the water, I'd want the maximum people looking, especially in cold water. And sadly jt11791 is on the money. Much of the time when someone falls in it is a body recovery operation. But body recovery is a far better result for the family than no body

[Wotname]

Originally Posted by MC2019

wrong PLB is an EPIRB with less battery life than a ship board
EPIRB.

Not exactly...
There are significant other differences between a PLB and an EPIRB other than battery life.

EPRIB are designed and certified to float; there is no requirement for a PLB to float.

Antenna design (polarisation ect) is quite different as a PLB is designed to radiate from a stable vertical position unlike a moving floating EPIRB.

Common usage now refers to various other PLBs on AISand VHF DSC frequencies. EPIRB only operate on 406 and 121.5 MHz. https://www.mrtsos.com/commercial/fa...-types-of-plbs

[goboatingnow]

All EPIRBs can be used as PLBs. Not all PLBs are EPIRBs however.

The PLB term is not generally applied to things like AIS MOB devices. These are more correctly “ SARTs” rathe then PLBs.

[goboatingnow]

Originally Posted by Wotname

Not exactly...

There are significant other differences between a PLB and an EPIRB other than battery life.



EPRIB are designed and certified to float; there is no requirement for a PLB to float.



Antenna design (polarisation ect) is quite different as a PLB is designed to radiate from a stable vertical position unlike a moving floating EPIRB.



Common usage now refers to various other PLBs on AISand VHF DSC frequencies. EPIRB only operate on 406 and 121.5 MHz. https://www.mrtsos.com/commercial/fa...-types-of-plbs

That article is basically “ junk “ and shows the author doesn’t under the subject or GMDSS.

“121.5MHz and AIS – predominantly the 121.5MHz will be used for alerting, with the AIS used to track and locate”

Wrong 121 isn’t used anymore for alerting

“AIS only – AIS is predominantly a tracking and locating technology and does not always give an audible alarm when an AIS PLB/MSLD is activated.”

An AIS mob /SART is specifically a tracking and locating tech and it’s supplied with a dedicated MMSI that specifically is designed to provide audible alarms and receiving devices must specifically treat the message as a GMDSS MOB alarm.

[goboatingnow]

Oh an MSLD is not a moniker used in the SAR world. I used to be a RNLI lifeboat station chairman.

It should also be pointed out that dual DSC altering AIS devices are operating in a grey area as DSC was not intended to be used in this way whereas AIS SARTs are an official IMO /ITU approved for the purpose of mob.

Hence an AIS mob device is better on my view that a PLB but in different ways. I have AIS MOB devices , A PLB and a ships EPIRB !

[MC2019]

I have been a delivery captain for 8 years, have a Fast Find 220 PLB .....

Thank god I have not had to use it, but it does function as an EPIRB in my delivery business .....

[Wotname]

Originally Posted by goboatingnow

That article is basically “ junk “ and shows the author doesn’t under the subject or GMDSS.

“121.5MHz and AIS – predominantly the 121.5MHz will be used for alerting, with the AIS used to track and locate”

Wrong 121 isn’t used anymore for alerting

“AIS only – AIS is predominantly a tracking and locating technology and does not always give an audible alarm when an AIS PLB/MSLD is activated.”

An AIS mob /SART is specifically a tracking and locating tech and it’s supplied with a dedicated MMSI that specifically is designed to provide audible alarms and receiving devices must specifically treat the message as a GMDSS MOB alarm.

You might like to let them know their article is junk. I am sure they wouldn't want to have misinformation associated with their brand and would appreciate having it corrected.

From their 'About Us' webpage - We’re proud to design, develop and manufacture a wide range of revolutionary PLBs and man overboard safety solutions for offshore industries and recreational applications.

We always put the person in danger at the forefront of our decisions..

Their history page makes for interesting reading -

1975 prototype PLB created
1979

Ken Kerr, one of MRT’s first customers, is successfully rescued 700 miles off Newfoundland in the Mid-Atlantic after activating his LOCAT radio distress beacon following a capsizing. His beacon signal was picked up by a Concorde flying overhead on its way to New York.

2001

After winning numerous awards as a family-run business, Marine Rescue Technologies Ltd is created. The innovative Sea Marshall brand is introduced to the commercial market, quickly becoming a global leader in man overboard safety equipment.

2014

The world’s first and to this day the only IECEx Zone 1 approved PLB. Operating on VHF DSC and AIS, the sMRT V100x allows O&G workers to be equipped with a PLB even in one of the most restricted, potentially explosive environments.

2021

After years of development MRT can finally reveal its plans to release the sMRT Shield, the world’s first 406MHz PLB with water activated AIS. The innovative addition to MRT’s product range will also utilise the Return Link Service (RLS) to once again offer the most comprehensive PLB to both the commercial and recreational marine sector. A land based ruggedised model that operates solely on 406MHz will also be available for the land based market, a first for MRT.

https://www.mrtsos.com/commercial/history

I have no association with MRT but I do have an interest in all things in the EPIRB / PLB world.

[goboatingnow]

Originally Posted by Wotname

You might like to let them know their article is junk. I am sure they wouldn't want to have misinformation associated with their brand and would appreciate having it corrected.



From their 'About Us' webpage - We’re proud to design, develop and manufacture a wide range of revolutionary PLBs and man overboard safety solutions for offshore industries and recreational applications.



We always put the person in danger at the forefront of our decisions..



Their history page makes for interesting reading -



1975 prototype PLB created

1979

2001

2014

2021

https://www.mrtsos.com/commercial/history



I have no association with MRT but I do have an interest in all things in the EPIRB / PLB world.

I’m sure it’s a fine company but the article author has no understanding of GMDSS approved SAR devices and how various things fit together and is confused by 121mhz beaconing

By the way RLS is a game changer allowing positive acknowledgement of distress beaconing.

Long term digest contact with high seas rescue centres by data or voice based systems will make all this stuff largely redundant. These days 75% of coastal rescue alerts come to MRCCs by mobile phone !!!