Piers
Well-Known Member
With the choice of differing capabilities and technologies coming on the market, I'm scratching my head wondering what to go for. Any advice gratefully accepted.
Thank you.
Piers
Thank you.
Piers
Personal Locator Beacon - or what?
- Thread starter Piers
- Start date
burgundyben
Well-Known Member
Good question, one I need to answer in the next couple of weeks.
Tranona
Well-Known Member
Three main choices. PLB which as the name implies are personal, so useful if you fall overboard. Location is by satellite. AIS locators, again personal but rely on an AIS receiver. EPIRB also satellitelocator plus GPS on some. Usually boat related and can be manual or automatic release.
No clear answer which to choose. The fact that all 3 exist suggests they are not direct substitutes for each other so individual choice reflects individual assessment of which will give most benefit or what sort of emergency you are likely to suffer.
If it is any help, based on the very limited data on active usage all have proven effective for some in the specific circumstances for which they were designed. That is some people have been saved after falling overboard because they had personal locators and many vessels, boats, aircraft, desert explorers, mountaineers etc in difficulty have been located by their EPIRB.
No clear answer which to choose. The fact that all 3 exist suggests they are not direct substitutes for each other so individual choice reflects individual assessment of which will give most benefit or what sort of emergency you are likely to suffer.
If it is any help, based on the very limited data on active usage all have proven effective for some in the specific circumstances for which they were designed. That is some people have been saved after falling overboard because they had personal locators and many vessels, boats, aircraft, desert explorers, mountaineers etc in difficulty have been located by their EPIRB.
burgundyben
Well-Known Member
I get the AIS beacon and how it is different. Its ideal for a MOB recovery, but not when in the middle of Lyme bay and the boat has sunk.
PLB and EPIRB - in practical terms not sure of the difference, they seem to have the same 406 and 121 technology onboard but packaged differently at different price points.
PLB and EPIRB - in practical terms not sure of the difference, they seem to have the same 406 and 121 technology onboard but packaged differently at different price points.
BruceK
Well-Known Member
I would imagine that the choice has more to do with where you cruise and how many onboard. PLB's come in two basic types unless my knowlege is outdated. VHF or sattelite transmission both with GPS. Personally if I was in inshore waters only and did not have a large crew I'd have each crew member on a cheaper VHF based PLB rather than a single boat / liferaft based EPIRB.
Tranona
Well-Known Member
Because they are different A PLB is a small device for wearing on the person. It is manually activated, and limited life. Useful if you fall overboard and will be located and rescued quickly. An EPIRB lasts longer can float, taken into a liferaft and transmits for longer. Use the same basic technology but at different levels of capability.
So if you think you are likely to fall overboard and want to increase your chances of being found before you drown use a personal locator. If you think your boat will get into difficulties and you need assistance and are outside the range of VHF, get an EPIRB. In our coastal waters for this situation you have VHF and DSC as the prime method of requesting assistance.
Of course, many people have all 3 means on their boat, particularly if going offshore. Most coastal sailors rely mainly on VHF and avoid falling overboard.
Nick_H
Well-Known Member
As I understand it, EPIRB has longer transmit time, about 5 days vs. a day or two for PLB, and will float upright on its own and continue to transmit, whereas PLB needs to be held above water.
When the yacht sank in the Atlantic over the winter the PLB only transmitted for two hours, as the crewmen must have been overcome by the cold.
An EPIRP on the boat, plus a PLB for yourself if you're the only trained person on board, seems sensible to me, although for coastal cruising you could argue just a PLB will cover 99% of distress situations for a very low cost.
Don't know much about personal AIS transponders, do they show as a distress on all surrounding AIS receivers?
prv
Well-Known Member
Electronically they're almost identical - apart from a longer battery life on an EPIRB, the differences are essentially physical / mechanical.
An EPIRB will float and transmit unattended. Most PLBs do not float, and the exceptions only float so that you don't lose them, they don't float the right way up with the aerial clear of the water. So you have to hold them while transmitting.
PLBs are small enough to carry in your pocket, on your belt, or in a lifejacket. EPIRBs are bulkier and have to be stowed on the boat.
EPIRBs will activate automatically if immersed, PLBs have to be activated manually by at least two physical steps (eg break off cover, press button).
EPIRBs are optionally available with an automatically-releasing bracket / housing, which has a water-activated element like a lifejacket. Such a bracket would be pointless for a PLB, because of the need for manual activation.
Taken together, these differences mean that a PLB is an inherently manual device, operated directly by a human being. An EPIRB in an auto housing can operate completely independently should the boat sink, with the crew not even being aware of it. Crews have been saved after sudden capsizes where the EPIRB released itself, floated to the surface, and sent a distress signal all on its own. The crew and the drifting beacon might not be in exactly the same place, but close enough for a helicopter or lifeboat to find them once in the area.
If you're not going to have an auto bracket mounted on deck, but rather rely on carrying the EPIRB into the liferaft with you, then you're not using most of these features and you might as well just use a PLB as a poor-man's EPIRB. The multi-day battery life is an irrelevance in European coastal waters. This is what I do.
A PLB is also the obvious choice if you want independent distress-signalling capability for your little pink body, as opposed to the boat as a whole
Pete
prv
Well-Known Member
They should show up on all AIS receivers within a few miles (with the exception of certain older Garmin firmware versions, when receiving a signal would crash the plotter!) but on older or more basic devices they may just appear as a ship. You can technically tell that it's a SART because the MMSI starts with a particular sequence, but it's not going to attract anybody's attention who wasn't already aware of the situation. Better displays will show the SART symbol (red X in a circle) and hopefully trigger an alarm, but the behaviour will probably be different in each case and the user is unlikely to be familiar with it. Many of the luddites over on Scuttlebutt would probably just slap it a couple of times and then turn it off
. And of course many boats will either not have AIS or will have it turned off - in clear weather I generally only use mine in mid-Channel. In summary, relying on an AIS SART to alert other boats is not really a sound proposition. So a singlehander for example is much better off with a PLB that will reliably inform the Coastguard of your position and distress.
What AIS SARTs are brilliant for is helping your own boat get back to you after you've fallen off. If you've bought the things you will presumably ensure that your own kit displays it properly, and that you and your crew are familiar with what it does. The beacons have a test mode which you can use to try it out. Then if someone falls over the side, they will pop up on your plotter and stay there, with a constantly-updated position, anywhere in a couple of miles' radius. How's that compared to someone with the regulation RYA pointing finger
Pete
Ripster
Well-Known Member
Just been through this whole PLB/epirb/AIS beacon thought process. There are generally only two of us sailing in coastal or channel waters. We have an ACS epirb on board (now aging a bit but tests ok) and a very ancient McMurdo PLB 200 - which is due for replacement. For this season, We wanted to get two of the newer compact devices and have these one with each LJ. We went for the PLB (Ocean Safety compact one) as these (in our opinion) seamed a better option (than AIS) for a wider range of possible situations.
bobgarrett
Well-Known Member
We have just been through similar question and concluded that since PLBs now also transmit on 406MHz they are nearly as good as an EPIRB. Yes they are not automatic but nor was our former EPIRB, and they have less battery life. However, for less than an EPIRB price we now have 2 PLBs we can wear. On thing I wish they had too was AIS transmit.
fisherman
Well-Known Member
Analyse the risk. I am single handed so carry a waterproof phone, PLB clipped to LJ, and this year have a standard horizon floaty handheld, haven't worked out how to wear it yet. Only thing is, all these require activation and there won't be much time before my hands are frozen.
noelex
Well-Known Member
+1
I came to the same conclusion.
I think importantly you can attach them to your lifejacket which means in the event of sudden emergency such as collision or fire you are more likely to have a means of attracting attention. Two PLB's for the same price a single EPIRB gives you redundancy. The risk of electrical failure of an EPIRB is not high, but there is a risk that events like fire could block your access to a single unit.
If you can get to a life-raft with your lifejacket and attached PLB you have a good chance of survival.
While better than nothing, I cannot see a PLB being a great deal of use in most MOB situations in cold water. Even in the warmer MED waters I think the response time is likely to be too slow for a reasonable chance of survival.
Piers
Well-Known Member
Thanks for all the feedback. It appears that,
1) AIS beacon - great of your boat is within 4nm of the MOB, have an AIS receiver, and the MOB is conscious to ensure the aerial is out of the water with the aerial vertical.
2) PLB - only notifies the authorities, not you in the boat.
3) SART - broadcasts a homing signal and depends if you can receive 406/121.5 and know the source of the transmission, which I certainly don't have.
So it looks like the AIS is the better option for finding your MOB, whereas the PLB is best if you can't fiund your MOB and the EPIRB is best if your boat goes down!
A fair summary?
1) AIS beacon - great of your boat is within 4nm of the MOB, have an AIS receiver, and the MOB is conscious to ensure the aerial is out of the water with the aerial vertical.
2) PLB - only notifies the authorities, not you in the boat.
3) SART - broadcasts a homing signal and depends if you can receive 406/121.5 and know the source of the transmission, which I certainly don't have.
So it looks like the AIS is the better option for finding your MOB, whereas the PLB is best if you can't fiund your MOB and the EPIRB is best if your boat goes down!
A fair summary?
ctva
Well-Known Member
Does the PLB need to be registered with Ofcom / Coastguard like the EPIRB?
prv
Well-Known Member
Yes. From an electronic / signalling point of view, they're essentially identical. The Coastguard treat them interchangeably.
Pete
prv
Well-Known Member
Yep.
No - the Kannad and McMurdo beacons (which are basically the same device with a different label) can be mounted on a lifejacket and rigged to activate when it inflates. So with an auto jacket, the whole lot is automatic. Budget permitting, and if you're in the habit of wearing lifejackets at all times so will have it with you, these things are an absolute game-changer for MOB.
Correct. And there's a definite lag between positions being sent by the beacon, received by Falmouth, phoned through to your local MRCC, and radioed out to you. So I wouldn't rely on being guided in to a MOB with pinpoint precision - they're designed to get a lifeboat into the general area so that it can home in via the 121.5 signal. You don't have a receiver for that.
Depends what you mean by SART.
A traditional SART operates on radar frequencies, it draws a distinctive line on a ship's radar screen and allows it to home in. Mandatory in ships' liferafts but not widely used in the leisure world.
The term is also being applied to other devices like AIS beacons, but you need to be clear about what that device actually is rather than just using the general term.
I don't know what you mean about 406/121.5 in this context - something working on those frequencies would be either an EPIRB or a PLB depending on its physical packaging. And 406 is not intended to be received by vessels at sea, that goes up to the satellites and down to Falmouth.
There were previously analogue 121.5-only beacons, often with a flexible aerial designed to be worn round the neck and a round button on the front. These are obsolescent now as they cannot raise the alarm, are local-area only, and homing on them requires special kit. AIS beacons are a complete and better replacement.
Pretty much. Though the PLB will largely substitute for an EPIRB in European waters (no need to transmit for days on end) if you have it on you and are in a fit state to use it.
Pete
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darryl_g
Member
We've got a PLB and AIS beacon on board.
My wife has the AIS beacon on her lifejacket. I've got the PLB on mine.
Rationale being that if she's overboard, I can pick her up. If I'm overboard we're buggered.
Darryl
My wife has the AIS beacon on her lifejacket. I've got the PLB on mine.
Rationale being that if she's overboard, I can pick her up. If I'm overboard we're buggered.
Darryl
noelex
Well-Known Member
The interesting bit is that two PLB's have roughly the same transmit time as a single EPIRB for roughly the same total cost.
The two PLB's could be set of sequentially if greater transmit time was required. The other option is to set off the two PLB's simultaneously. This gives redundancy.
There are a lot of false alarms with EPIRB's and PLB's. I wonder if the authorities would take the activation of two PLB's in the same location as less likely to false alarm? It would seem a logical conclusion that the accidental deployment of two units is unlikely, but I have no idea of the official policy.
I have read of tragedies where the authorities, incorrectly, strongly suspected a false alarm.
Piers
Well-Known Member
Thanks Pete. Really helpful. I'll go the AIS route for our LJs. Already have a EPIRB for the boat.
