ACR EPIRB vs Resqlink PLB

[grantmc]

As others said 48 hours vs 24 hours. But this feature is more than just battery. EPIRBS must float for at least 48 hours and their signal keeps going on any angle. So they're designed for floating in water, even if tossed about in a life raft.
Not all PLBs float, and should be held upright for signal to work.

Cat 1 EPIRBS have a self release and self deploy when they detect more than 2 metres of water above them. These are obviously intended for deck mounting.

EPIRBS must have a strobe light PLBs don't usually.

You register your vessel's details when you buy an EPIRB. It's a world wide system so that an RCC in any country will know what they're looking for. Obviously no such need for PLB.

I think an EPIRB is essential equipment when doing offshore trips. Plus it's mounted in my boat and I'll not forget to take it with me.

[Dockhead]

Originally Posted by noelex 77

. . . Personally, I think a PLB attached to a lifejacket/harness is probably a better solution than an EPIRB. You are more likely to have the PLB in an emergency situation. I think this is probably more of an advantage than the longer batter life of an EPIRB.. .

I agree with that entirely. So I would say if you're choosing between the two, buy the PLB first. The PLB is always on your person. Actually, a PLB for every crewman is a really good idea -- that's what we had in the Arctic last summer. Then if there's money left over -- and EPIRB for the ship. But I would start with the PLB, and keep it in your life jacket.

[Quadrille in JB]

We have used our Garmn In-Reach in the Med, the Baltic, Scandinavia, Central America and the Bahamas where it worked flawlessly to send and receive texts with no time delay. At least this shows it was in constant communication with a satellite. Usually much better than our Irridium sat phone which often drops calls and/or becomes unintelligible.
I’m constantly amazed at how well it works, especially for the initial price and for the $25 per month.

[Dockhead]

Originally Posted by Quadrille in JB

We have used our Garmn In-Reach in the Med, the Baltic, Scandinavia, Central America and the Bahamas where it worked flawlessly to send and receive texts with no time delay. At least this shows it was in constant communication with a satellite. Usually much better than our Irridium sat phone which often drops calls and/or becomes unintelligible.
I’m constantly amazed at how well it works, especially for the initial price and for the $25 per month.

We were talking about distress comms.


Yes, the In-Reach and other sat devices -- I used an Iridium "Go" in the Arctic last summer -- are great. But these are of limited use for distress comms -- we were talking about EPIRBs and PLBs.

[Quadrille in JB]

I was trying to point out, obviously unsuccessfully, the great connectivity of the In-Reach should make it good for distress and rescue purposes.
Why would it be limited for these purposes, especially with the 2-way communications that you don’t get with an EPIRB.

[Dockhead]

Originally Posted by Quadrille in JB

I was trying to point out, obviously unsuccessfully, the great connectivity of the In-Reach should make it good for distress and rescue purposes.
Why would it be limited for these purposes, especially with the 2-way communications that you don’t get with an EPIRB.

Two-way communications are extremely valuable, but such devices as "In-Reach" are not part of the GMDSS system. They won't work if your subscription runs out (Rebel Heart case) or if the messaging center mishandles your message or if the rechargeable battery runs out or doesn't happen to be charged up or if there is some kind of disruption in the Iridium system which handles vast volumes of ordinary traffic.



EPIRBs and PLB's are specific dedicated distress signalling devices which are primary elements of the GMDSS system and which connect directly to SAR services and not via some messaging center. They can't be used for ordinary traffic and don't have rechargeable batteries, so all you do is keep them in date and you can depend on their being power. On top of all that, they emit a 121.5mhz homing signal to guide the rescuers in for the last mile.


In-Reach is great -- but in ADDITION to an EPIRB or PLB, not INSTEAD. Pop the EPIRB first; then start trying to raise two-way comms, in case of a disaster.

[Quadrille in JB]

Originally Posted by Dockhead

Two-way communications are extremely valuable, but such devices as "In-Reach" are not part of the GMDSS system. They won't work if your subscription runs out (Rebel Heart case) or if the messaging center mishandles your message or if the rechargeable battery runs out or doesn't happen to be charged up or if there is some kind of disruption in the Iridium system which handles vast volumes of ordinary traffic.



EPIRBs and PLB's are specific dedicated distress signalling devices which are primary elements of the GMDSS system and which connect directly to SAR services and not via some messaging center. They can't be used for ordinary traffic and don't have rechargeable batteries, so all you do is keep them in date and you can depend on their being power. On top of all that, they emit a 121.5mhz homing signal to guide the rescuers in for the last mile.


In-Reach is great -- but in ADDITION to an EPIRB or PLB, not INSTEAD. Pop the EPIRB first; then start trying to raise two-way comms, in case of a disaster.

Point well taken.
Thank you

[skipmac]

Originally Posted by meirriba

I think you are mixing 3 separate scenarios.
The personal AIS systems is perfect for searching after a crew member that fell into the sea. It would not help a solo sailor who needs a PLB and would not help in case of a boat in distress on high seas that needs an EPIRB.

Didn't think I was mixing anything, just adding additional information and an alternative.

Of course an AIS MOB transponder won't help a singlehander but the OP did not ask about singlehanding.

There are uses for all three options: EPIRB, PLB, and a personal AIS. I carry an EPIRB and will be adding personal AIS MOB units next since I usually sail with crew. If I do a solo i will add a PLB.

[grantmc]

One aspect that all personal PLB/AIS transponders require is that when you do fall over board you have it firmly attached to your person. It's useless tucked in the pocket of a jacket not being worn.

And to me that's a weak link. Many people wont even wear a PFD let alone use a safety line during daylight. And certainly not when out for a nice sunny Sunday afternoon sail, when most people fall off.

[TrentM]

Taking a lesson from the Bertie capsize...

(http://www.cruisersforum.com/forums/...nj-218901.html)

A Category 1 EPIRB would have gone off immediately and automatically (or would have been more accessible for them to swim to if it was under only a couple feet of water). Their Category 2 EPRIB was inaccessible for 30 minutes. They're quite lucky they still had the energy to swim to it at that point.

A PLB likewise would have been a great thing for both to be wearing. If you fall overboard your EPIRB won't know and won't care but you can activate your PLB. And because of that I would say if your budget is such that you can't afford both then a PLB might be the right choice. But it's probably best to find a way to fit both into your budget.

[Dockhead]

Originally Posted by TrentM

Taking a lesson from the Bertie capsize...

(http://www.cruisersforum.com/forums/...nj-218901.html)

A Category 1 EPIRB would have gone off immediately and automatically (or would have been more accessible for them to swim to if it was under only a couple feet of water). Their Category 2 EPRIB was inaccessible for 30 minutes. They're quite lucky they still had the energy to swim to it at that point.

A PLB likewise would have been a great thing for both to be wearing. If you fall overboard your EPIRB won't know and won't care but you can activate your PLB. And because of that I would say if your budget is such that you can't afford both then a PLB might be the right choice. But it's probably best to find a way to fit both into your budget.

Yep!

[Dockhead]

Originally Posted by skipmac

. . .

There are uses for all three options: EPIRB, PLB, and a personal AIS. I carry an EPIRB and will be adding personal AIS MOB units next since I usually sail with crew. If I do a solo i will add a PLB.

And you can add a fourth -- a DSC handheld VHF.


All of these devices are complementary to each other; I have all of them on my boat and wouldn't want to be without any one of them.


The AIS MOB devices are really game changing things -- if a MOB goes over having such a device on his person (the challenge to that premise in another post duly noted, however), then the whole issue of finding the casualty is more or less eliminated -- probably most MOB's who don't survive, are simply never found, so this is a major threshold challenge, especially in cold water where time to find the casualty is severely limited.


But these devices are good for more than just MOB -- also excellent for last mile signalling from the life raft. How many life raft survivors were passed by, by ships which saw neither the raft nor their flares?


DSC handheld is also good for that, plus two way comms with rescuers once they get close -- something SAR workers themselves are always saying they wish they had.



In case of going overboard when solo, a PLB may or may not get you saved. In cold water, given the long response time through the GMDSS system, it's not likely probably, unless you're wearing a drysuit. I think even solo you want to have the AIS MOB beacon just in case there is some other vessel within range -- which is in many cases going to be your best hope anyway. Big difference between the AIS MOB beacon and a PLB is that the AIS MOB beacon instantly alerts nearby vessels -- no processing no protocols, no work on finding and raising comms to nearby vessels, etc., etc., which normally burn an hour or two at least when getting help via EPIRB or PLB.

[Wotname]

THIS...

Originally Posted by a64pilot

............

...... but I will always believe that an EPIRB will more likely transmit a signal that will be received better than a PLB.
You read of accidents that the RCC only gets a couple of “hits” from a PLB.......
.........

While the transmit power of a PLB and EPIRB is identical and the antennas are equally efficient when used as designed, there is a world of difference in the received signal strength at the satellite receiver between a floating EPIRB and PLB attached to a MOB.
An EPIBB is designed to be used floating in a seaway and the antenna is designed to accommodate this. A PLB is designed to sitting on the ground (or a vehicle roof or similar) and be stationary. It's antenna works very well in this arrangement. However, when attached to a MOB bobbing around in the waves, the antenna isn't so good. Ideally the PLB should be held up with the antenna vertical and as high as possible in order to get a good transmission. Clearly this isn't isn't easily achieved for very long by the MOB.

Please note either beacon only transmits once every minute so in order to get say ten transmissions, the MOB has to hold the PLB correctly for ten minutes in order to achieve maximum signal strength for the ten transmissions. .

That said, a weak signal is usually enough to get the SAR guys mobile .

FWIW, I have both!

Originally Posted by a64pilot

I was surprised you ever could, GPS is just a chip, and cheap, phones all kinds of devices have GPS now, I bet maybe even some watches do.
I always figured it was a marketers dream, charge $100 extra for a .50c chip.

There is probably some truth in this but there are other more important considerations.

GPS chips aren't created equal. Some have say one or two receivers, others have twelve 12 receivers and others may have fifty or more (all in the one chip).

This has an huge impact on cold start performance (time to achieve a GPS position lock) and current draw. Both are important to the user. Some GPS receivers can achieve a position lock by the time the beacon transmits it's first data burst.

By the way, be aware that all beacons take about one minute after activation before they transmit an active distress signal. The initial transmission that occurs at turn on is coded as a non distress (or test) signal. The next transmission a minute later is coded as an genuine distress signal.

Current draw of a GPS chip is a huge problem for the designer of a beacon, it's cuts into the battery capacity - remember the beacon has to perform to a standard (48 hours for an EPIRB and 24 hours for a PLB). Designers get creative with the GPS performance as there is no current standard for GPS performance.

Some turn the GPS chip off after a short time, say 5 or 30 minutes - in effect, only an initial position is transmitted. Others cycle the operational time of the GPS chip, say on for a few minutes, off for an hour.

However this information is not listed in the marketing hype of the beacons.

AFAIK, the only manufacturer that publicly states the GPS chip performance is KTI. I guess because their performance is the best - the GPS chip stays active continuously (while the beacon is on).

[Dockhead]

Originally Posted by Wotname

. . . While the transmit power of a PLB and EPIRB is identical and the antennas are equally efficient when used as designed, there is a world of difference in the received signal strength at the satellite receiver between a floating EPIRB and PLB attached to a MOB.
An EPIBB is designed to be used floating in a seaway and the antenna is designed to accommodate this. A PLB is designed to sitting on the ground (or a vehicle roof or similar) and be stationary. It's antenna works very well in this arrangement. However, when attached to a MOB bobbing around in the waves, the antenna isn't so good. Ideally the PLB should be held up with the antenna vertical and as high as possible in order to get a good transmission. Clearly this isn't isn't easily achieved for very long by the MOB.

Please note either beacon only transmits once every minute so in order to get say ten transmissions, the MOB has to hold the PLB correctly for ten minutes in order to achieve maximum signal strength for the ten transmissions. .

Sure, but neither EPIRB nor PLB is much use in an MOB situation anyway, so I don't think your choice should be oriented to this use case.


It is certainly true that you have to know how to deploy and orient the antenna on a PLB, so it is for sure less idiot-proof than an EPIRB. But do we know of ANY cases of sailors who deployed PLB's from their boat or life raft (this is the correct use case to analyze, not MOB) and did not get their signal received? I've never heard of one.



I am willing to be educated if I'm wrong about this, but I have read here and there that the system is extremely reliable (part of its design spec) and that the risk of not getting your signal through is vanishingly low with PLB's if you are vaguely using the antenna right. I'd be glad to be corrected, however, if I am misinformed about this.


Like you, I carry both, but I've always believed that I could really count on the PLB in case of disaster. And as others have written in this thread, the PLB has the massive advantage of its being far less likely to get lost in the shuffle in case of some sudden disaster which requires an urgent abandonment, since you can keep it on your person. Mine lives in my life jacket, which I'm wearing more and more these days, and which would anyway be the first thing I would grab in case I had to leave the ship in a hurry.


I also take my PLB with me on land in remote places. Last summer in the Arctic I required everyone on board to have his own PLB.

[Wotname]

Originally Posted by Dockhead

Sure, but neither EPIRB nor PLB is much use in an MOB situation anyway, so I don't think your choice should be oriented to this use case.

I concur. I was being a lazy in my post by using "MOB" as shorthand for finding oneself in the water without a boat i.e. boat sunk. In such instances, I would prefer to have EPIRB floating with me and the rest of the crew but YMMV. In a "proper" MOB i.e. one crew in the water and the rest aboard, neither are really useful but a PLB would be better than nothing.


It is certainly true that you have to know how to deploy and orient the antenna on a PLB, so it is for sure less idiot-proof than an EPIRB. But do we know of ANY cases of sailors who deployed PLB's from their boat or life raft (this is the correct use case to analyze, not MOB) and did not get their signal received? I've never heard of one.

Neither have I, see more below. As an aside, I have always understood the correct way to activate an EPRIB from a life raft is to allow it to float tethered to the raft. This is then fuss free and allows the EPIRB to radiate as designed.



I am willing to be educated if I'm wrong about this, but I have read here and there that the system is extremely reliable (part of its design spec) and that the risk of not getting your signal through is vanishingly low with PLB's if you are vaguely using the antenna right. I'd be glad to be corrected, however, if I am misinformed about this.

Yes I concur, the system is robust and extremely reliable - possibly the most reliable electronic device any of us will ever encounter outside some exotic military secret squirrel stuff or a deep space probe.

However after lifetime as an RF professional I would suggest a better description might be "the risk of not getting your signal through is vanishingly low with PLB's if you are vaguely using the antenna right some of the time".

I don't have firm data on this aspect but I do have some personal experience with beacons transmitting (unintentionally) with no antennas or with broken antennas. As with any weak RF signal, what gets though to a receiver can be surprising! One case involved a beacon transmitting with no antenna inside a closed metal aircraft hanger, the RCC was calling us inside 5 minutes while on another occasion, a beacon was transmitting in a similar condition for several hours without triggering a response. It was only noticed when a receiver metres away was tuned up to 121.5!

Suffice to say, you better results when using the equipment as designed!!!

Like you, I carry both, but I've always believed that I could really count on the PLB in case of disaster. And as others have written in this thread, the PLB has the massive advantage of its being far less likely to get lost in the shuffle in case of some sudden disaster which requires an urgent abandonment, since you can keep it on your person. Mine lives in my life jacket, which I'm wearing more and more these days, and which would anyway be the first thing I would grab in case I had to leave the ship in a hurry.

My thoughts are slightly different. In my opinion , the EPRIB is for the ship, the PLB is for the person.

If the ship is in trouble, activate the EPIRB and let it do it's thing fuss free and unattended while crew does whatever else needs to be done. This has to tempered to the situation and type of emergency, type of vessel and type of crew but at the end of the day, the designed purpose of a maritime EPIRB is to get an MAYDAY alert to a distant RCC and it's all round design is to achieve this in a wide variety of maritime emergencies.

If a person is trouble (and not the vessel) I would activate the PLB accordingly.

And if both as in trouble and the person (crew) are separated from the EPRIB (activated or not), it is time to use the PLB.


I also take my PLB with me on land in remote places. Last summer in the Arctic I required everyone on board to have his own PLB.

Like you, I carry the PLB when riding in remote areas.

I don't know about RCC in other parts of the world but in Australia you can link any number of PLBs to your EPRIB registration and add notes to each one. I have (in the past) assigned names to each PLB and at other times, activities (and locations) that pertain to the PLB use apart form sailing. This is all user performed by a passworded access to the RCC registration database.

Is the UK (or USA) similar?