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Old 16-09-2012, 17:14   #16
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Re: EPIRB or PLB info direct to boat?

So the AIS thing is interesting. However the size of those personal AIS devices is a worry- and wouldn't the fact that it's low in the water give it the same range issues as a VHF device?

What I'm saying really is...

You can get tiny VHF devices, you can get tiny Erirb PLB devices. Would be great to get both in one device so you don't need the extra bulk of 2 batt's, two areals, etc.
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Old 16-09-2012, 17:21   #17
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Re: EPIRB or PLB info direct to boat?

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Originally Posted by jeremiason View Post
.........
As a result, no one in the Maritime and Aviation industries are carrying 121.5 MHz receiving units any longer and no satellites are listening.
You are correct in that satellites are not listening but some sections of the aviation industry are. I can't speak for your part of the world (or for the maritime aspects) but 121.5 is still regularly monitored by civil aviation down under and as explained above, still used for active homing by SAR aircraft.

We regularly test beacons and while we can transmit for up to say 40 seconds before triggering an 406 alert, the local airport tower gets grumpy if the accompanying 121.5 transmission exceeds a few seconds (say around 3). Perhaps they don't like the annoying swept AF tone in their "office"
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Old 16-09-2012, 17:40   #18
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Re: EPIRB or PLB info direct to boat?

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Originally Posted by simonpickard View Post
So the AIS thing is interesting. However the size of those personal AIS devices is a worry- and wouldn't the fact that it's low in the water give it the same range issues as a VHF device?

What I'm saying really is...

You can get tiny VHF devices, you can get tiny Erirb PLB devices. Would be great to get both in one device so you don't need the extra bulk of 2 batt's, two areals, etc.
I hear you . My take is that an on board 406 receiver and decoder would give the best solution providing the PLB was GPS embedded (GPLB??).

I realize range would be short but with a mast mounted UHF (406) / VHF antenna, a range of 5 + miles should be obtainable. The audio from the 121.5 would trigger the receiver to light up the bells and whistles on board alerting the remaining crew. This would happened immediately once the beacon was activated and the 406 transmission bust coming in 60 seconds later (and then at every minute) would contain the GPS lat. and long. which would be hard wired into the chart plotter as well as synthesised into a voice readout.

The vessel who lost the MOB should surely be the closest to respond and the one who SHOULD do so .

I have raised this before but usually get shouted down with stuff along the lines "leave it to the professionals, they are the experts in SAR and so" or "it won't work, leave it to the satellites"

There are some technical difficulties for the receiver design but nothing too impossible and as the we are talking receiver only, the approval paperwork would (should?) be minimal.
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Old 16-09-2012, 18:42   #19
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Re: EPIRB or PLB info direct to boat?

Well hopefully someone out there is thinking the same thing and pushing this tech forward.
I heard the other day that there's a 1 in 10 chance when offshore of getting recovered once overboard at sea. The ideas being talked about here would surly improve those odds hugely.
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Old 16-09-2012, 19:02   #20
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Re: EPIRB or PLB info direct to boat?

As has been mentioned, the 121.5 MHz beacon is still broadcast by the latest generation of PLBs, EPIRBs, and GPIRBs. It is no longer monitored by the satellites, but it is used by the SAR responders as they home in on the victim. I don't think that this feature will be eliminated any time soon, since the 406 MHz short-burst signal is not suitable for direction-finding.

As far as I can tell, most modern EPIRBS and PLBs do include the GPS position encoding capability. Certainly the ones that I carry on VALIS are so-equipped. Is it even possible to buy a non-GPS PLB any more? All of the ones currently sold by ACR and McMurdo contain a built-in GPS.

While I like the idea of a 406 MHz EPIRB/PLB receiver that would display the position of the victim, it seems that the new AIS beacons are likely to become the preferred solution. For self-rescue (by the crew still on your boat) this is a really good solution. These devices are about the size of a PLB, and the price is only going to go down as the volumes increase. They work with an existing AIS receiver/display, so for many boats no additional equipment will be needed.

The other MOB devices, such as Raymarine's "Lifetag" can be a less expensive solution (perhaps), but they have drawbacks for the type of sailing I do. They do auto-activate, which is a very good thing.
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Old 16-09-2012, 19:45   #21
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Re: EPIRB or PLB info direct to boat?

MOB crew monitoring system, when someone enters the water an alarm sounds on the boat.
East Marine - marine accessories equipment and repairs

AIS/GPS personal locator beacon. Attaches to life jacket. When it inflates the beacon is activated. AIS technology sends location information back to boat and AIS radio on boat gives bearing and distance back to MOB.
Sail-World.com : World-first AIS/GPS personal device approved for sale

Maybe the first device is the best since it does direct back to MOB and it is possible for someone to go overboard and not be noticed
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Old 16-09-2012, 20:08   #22
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Re: EPIRB or PLB info direct to boat?

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Originally Posted by westwinds View Post
MOB crew monitoring system, when someone enters the water an alarm sounds on the boat.
East Marine - marine accessories equipment and repairs
AIS/GPS personal locator beacon. Attaches to life jacket. When it inflates the beacon is activated. AIS technology sends location information back to boat and AIS radio on boat gives bearing and distance back to MOB.
Sail-World.com : World-first AIS/GPS personal device approved for sale
Seems to me devices are needed, one to signal MOB and the other to determine is location
The AIS/GPS MOB beacon described in the link is the Kannad R10. I have these installed in my crew's PFDs. When activated, an alarm sounds on my AIS monitoring software (NavMonPc, which I wrote and give away).

Some chartplotters or other AIS monitoring units also recognize the beacon as a MOB device and will sound an alarm. Most any AIS monitor / chartplotter can be configured to sound a simple proximity alarm, but this would need to be set for perhaps two miles (since the MOB needs to trigger the beacon, and the beacon takes a little time to transmit it's location). The technology is evolving, but the AIS/GPS MOB beacon, when paired with an appropriate on-boat receiver/monitor (which can be a chartplotter) is a complete self-rescue beacon system.

For what it's worth, I also have PLBs installed in our PFDs. This is really too much junk to be carrying, but I still haven't decided if I want to give up the features of the PLB.
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Old 17-09-2012, 07:17   #23
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Re: EPIRB or PLB info direct to boat?

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Originally Posted by simonpickard View Post
Well hopefully someone out there is thinking the same thing and pushing this tech forward.
They are. Standards agencies are even now working on sussing out how this should be done.

Here's a link to some information.
Panbo: The Marine Electronics Weblog: AIS MOB devices, we're in the learning phase!
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Old 17-09-2012, 09:16   #24
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Re: EPIRB or PLB info direct to boat?

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Originally Posted by Paul Elliott View Post
............

As far as I can tell, most modern EPIRBS and PLBs do include the GPS position encoding capability. Certainly the ones that I carry on VALIS are so-equipped. Is it even possible to buy a non-GPS PLB any more? All of the ones currently sold by ACR and McMurdo contain a built-in GPS.
Well, yes, non GPS PLBs are still available but with the difference in price being $50 or less, why would anyone opt for a non GPS unit

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Originally Posted by Paul Elliott View Post
While I like the idea of a 406 MHz EPIRB/PLB receiver that would display the position of the victim, it seems that the new AIS beacons are likely to become the preferred solution. For self-rescue (by the crew still on your boat) this is a really good solution. These devices are about the size of a PLB, and the price is only going to go down as the volumes increase. They work with an existing AIS receiver/display, so for many boats no additional equipment will be needed.
.
I suspect you are right; if only because theses is much more money to be made in the AIS option and it is less technical to fit (i.e. sell). IMO, the AIS option is an OK arrangement for the average weekend punter but for the off-shore cruiser, it is a poor cousin compared to an on-board 406 receiver/decoder. To my mind, no one wants to have multiple units strapped to their PFD and if I go over the side, I would rather have both the distant RCC and my skipper know where I am all from the one unit.
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Old 17-09-2012, 10:14   #25
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Re: EPIRB or PLB info direct to boat?

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IMO, the AIS option is an OK arrangement for the average weekend punter but for the off-shore cruiser, it is a poor cousin compared to an on-board 406 receiver/decoder. To my mind, no one wants to have multiple units strapped to their PFD and if I go over the side, I would rather have both the distant RCC and my skipper know where I am all from the one unit.
I agree completely. In my case, the PLB and AIS/MOB units are tucked inside the auto-inflate PFDs, so they don't get in the way. It does add to the weight, and when you add the strobe and flashlight also inside the PFD we're talking about a fairly heavy load. Also, the multiple units add to the complication and likely confusion for the MOB. Still, it's better than not having the gear.

I'm certainly not arguing that everyone else needs to equip their crew with this much MOB junk. I just can't convince myself to get rid of any of it, since it all serves some purpose. I'm sure that better solutions will appear.
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Old 17-09-2012, 10:19   #26
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Re: EPIRB or PLB info direct to boat?

Most of everyone's comments above are valid. The first question is about the ability of a person on a vessel to locate a man overboard. To answer that question, the best thing is to purchase a unit that alarms on the vessel when a person goes overboard and have them wear a PLB with a strobe light. MOB alarms have been available for years. If you wake up and go on deck a couple hours after a person falls over board, you will be way out of range to pick up a signal from an antenna that is at sea level. The math for a reciever's DF distance is simple, and it limits most receivers on boats to a max of much less than 10 miles. I've done serious testing with antennas on 406 and 121.5 MHz.

121.5 is alive and well on aircraft direction finding receivers but new technology receivers for the USCG aircraft are now using 406 MHz DF capability that can lock onto the 5 watt 1/2 second transmission along with the weaker 25-50 milliwatt 121.5 signal. The 406 MHz signal is picked up immediately by geostationary satellites fixed overhead, and if you purchase a PLB or EPIRB with gps your position will be quickly forwarded to the AMVER program by the local country's coast guard so ships in the AMVER program will be directed towards the man overboard's 406 beacon untiil aircraft can get on scene. Commercial ships don't have the ability to DF on PLBs and EPIRBs, so the gps position in the beacon is very important. If you didn't get a beacon with gps, then you will have to wait for a low earth orbiting satellite to pass over the beacon to get a fairly accurate position (3-5 km radius). Bottom line, buy a 406 beacon with gps so you can call on a sat phone or a SSB radio to find out your man overboard's position. If you have an AIS receiver onboard you will be ready for new technology 406 beacons that also transmit AIS position. Every year new technology is making offshore cruising safer. One of my goals is to get every country to get 406 MHz direction finders in their coast guard aircraft, and eliminate !
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Old 17-09-2012, 10:31   #27
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Re: EPIRB or PLB info direct to boat?

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.....Every year new technology is making offshore cruising safer. One of my goals is to get every country to get 406 MHz direction finders in their coast guard aircraft, and eliminate !
Yep, new technology is fast. So fast that by the time 406 DFs are commonplace, they will be very second rate compared to just plotting the GPS co-ordinates .

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..... If you have an AIS receiver onboard you will be ready for new technology 406 beacons that also transmit AIS position.
Perhaps I have missed something, are you saying that 406 PLBs are being developed to concurrently transmit a VHF AIS signal?
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Old 17-09-2012, 10:47   #28
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Re: EPIRB or PLB info direct to boat?

Lots of people in favor of GPLBs here, but when I go in the water and activate the thing I still have to wait until time to first fix before it can send anything other than the 406 alert. Depending on conditions, that time could be quite significant. If my crew is coming back after me I'd prefer something that also includes DF capabilities, so that they don't have to rely on a position that may be a while in coming. I'd prefer not to stay in the water that long.

Wholeheartedly would not buy an EPIRB/PLB without GPS capability, but it's not instantaneous, and when the water is cold the optimal device should include functionality that doesn't require deciphering weak satellite signals. Maybe one day we'll see it all in one device.
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Old 17-09-2012, 11:06   #29
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Re: EPIRB or PLB info direct to boat?

"get every country to get 406 MHz direction finders in their coast guard aircraft,"

What aircraft? Not every country has them, so first, you'll need to form government SAR groups.

Even in the the Port of New York, the nearest USCG aircraft come from Atlantic City (about 120 miles away) or Boston (even further) and the first responders are city, county, and state assets from a mix of agencies.

Then there are days the USCG has no operational aircraft in an area, because their budget isn't sufficient to maintain spares.
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Old 17-09-2012, 11:15   #30
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Re: EPIRB or PLB info direct to boat?

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Lots of people in favor of GPLBs here, but when I go in the water and activate the thing I still have to wait until time to first fix before it can send anything other than the 406 alert. Depending on conditions, that time could be quite significant. If my crew is coming back after me I'd prefer something that also includes DF capabilities, so that they don't have to rely on a position that may be a while in coming. I'd prefer not to stay in the water that long.

Wholeheartedly would not buy an EPIRB/PLB without GPS capability, but it's not instantaneous, and when the water is cold the optimal device should include functionality that doesn't require deciphering weak satellite signals. Maybe one day we'll see it all in one device.
Ah... but once again, that is the beauty of the system I propose. You go into the water, pop the GPLB switch and instantly your crew know you are over the side. The on-board alarm has been triggered by the AF from the 121.5 component of the GPLB. Within 2 minutes, your GPS co-ordinates are flashed up on their chart plotter via the 406 digital component and as a back up, are also voice synthesised.

Can't get much quicker than that.

Assuming your crew are reasonably skilled, they turn around and return to your current position. After they get you on board and settled down they get on the blower and let the RCC know that the rescue has been completed and they don't require any SAR assets to attend.

The RCC says "nice one chaps, saved us a bucket load of money but do let us know if there is anything else we can for you today"
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