MOB on ARC.

[tsenator]

Originally Posted by davil

Originally Posted by PippaB View Post
For the AIS MOB beacon to give position it has to get a GNSS fix.



Not my understanding
__________________

EXACTLY My understanding too. Its mostly Line of sight VHF technology.

[tsenator]

Originally Posted by donradcliffe

I have a couple of questions. Is it possible to test these units without setting off a full scale man hunt? Do they have the range to be picked up by any of the commercial AIS services or Coast Guards?
.

I have tested my AIS personal beacon , it has a test mode that I was able to use and triggered VHF AIS on boat.... It worked ok, but I was on land, not much of a test. No Coast Guard was summoned

[tsenator]

So sad 😞. Not sure what happened, it said he had a “personal AIS beacon” What type I do not know. While those are great they don’t go off automatically when you hit the water. One “hopes” that they activate when the jacket inflates. But that seems like a very questionable method of turning it on. Then you have to manually activate it.

Maybe he was incapacitated and couldn’t do that. Even then its distance is limited especially when you are in the water. Makes one think they should have a Satellite (EPIRB type) PLB also .

Talking to manufactures in past years they said the “international agency’s” have been keeping the manufactures from combining Satellite PLB and AIS personal beacons from being in the same device for years. They need to change that !

[requiem]

Originally Posted by thinwater

Several incorrect assumptions because you did not watch the video.

• It was attached to the PFD.
• It autodeployed incorrectly. This was sort of the point of watching the video.

Indeed! Having now watched the video I can see that's the case. I don't much like that bend at the base of the antenna. There are two other things that jump out at me.

The first is the slide: I know when I mounted mine, I had a concern about the inflation tube blocking the slide and so made sure it pulled from the other side.

The second is the location of the inflation tube: it looks like on that model PDF it would be easy for the tether to slip upwards to the narrower section by the neck, which mean there isn't sufficient force to pull the clip free.

[slipaway]

Originally Posted by PippaB

Vesper is a manufacturer of AIS units, now owned by Garmin, and would thus be the recipient of an AIS MOB transmission.

An AIS-only MOB beacon would not be received by Garmin or anyone other then an AIS-receive vessel or aircraft that was within VHF-FM range of a person floating in the water. So far as I know, no personal AIS beacon is receivable by satellite unless it is one of the newly approved (in the US) combined AIS/PLB beacons.

[bergius]

Originally Posted by tsenator

Talking to manufactures in past years they said the “international agency’s” have been keeping the manufactures from combining Satellite PLB and AIS personal beacons from being in the same device for years. They need to change that !

There is at least one on the market, the rescueME PLB3.
While in this particular case that could have helped (assuming the life jacket inflated and the device activated as planned), we elected to go with the simpler AIS-only units, mainly for the reason that the combined unit is quite bulky.

PLB-only MOB devices tend to have the problem that if they activate accidentally, the first time you know about it might be when coast guard comes knocking. We've seen this happen multiple times this year on neighbouring boats (in one case RNLI spent hours going through all boats in Oban Transit Marina). At least with AIS (or combined) beacon you also get the alarm.

On Ocean Breeze, one question is where their AIS antenna is positioned. If on rail, then AIS distance to see device transmitting maybe 20cm above sea level is very short indeed.

Our boat is a lot slower, and we have the antenna at the top of the mast, so if MOB were to happen, there is hopefully a lot more time for the boat to receive the signal and rouse the sleeping off-watch. I'm considering if the person on watch should start carrying the boat's Inreach Mini as the second alerting option.

Sad incident, we watched them motor by to ARC start not that long ago.

[slipaway]

Originally Posted by tsenator

Talking to manufactures in past years they said the “international agency’s” have been keeping the manufactures from combining Satellite PLB and AIS personal beacons from being in the same device for years. They need to change that !

This has changed. About 2 years ago the FCC approved the combined PLB/AIS (and EPIRB/AIS) beacons for US use and registration. There are several on the market (ACR and McMurdo are 2 manufacturers). They transmit the local VHF-FM AIS signal the same as the existing AIS MOB beacons and also send to the SARSAT satellite system which provides for global alerting to a SAR agency (in the US that would be the USCG for maritime areas). They also transmit a homing signal (on 121.5 UHF) which can be used by SAR search aircraft. In many ways they are the best of both worlds. The PLB models are designed to be attached to lifejackets and for inflatables can auto activate as it inflates.

[tsenator]

Originally Posted by slipaway

This has changed. About 2 years ago the FCC approved the combined PLB/AIS (and EPIRB/AIS) beacons for US use and registration. There are several on the market (ACR and McMurdo are 2 .

Thanks for the update !

[PippaB]

Originally Posted by slipaway

An AIS-only MOB beacon would not be received by Garmin or anyone other then an AIS-receive vessel or aircraft that was within VHF-FM range of a person floating in the water. So far as I know, no personal AIS beacon is receivable by satellite unless it is one of the newly approved (in the US) combined AIS/PLB beacons.

Poor wording on my part. I was trying to say that Vesper/Garmin makes AIS units that are installed on boats, and such a unit installed on the boat would be the thing that receives the signal from an MOB beacon when it is in range (not terribly far).

Was not trying to indicate that Vesper/Garmin, the companies, maintain any kind of watch and would receive the signals (they don't and they won't).

[barnakiel]

Originally Posted by Montanan

What do the squiggly lines represent?

Mothership search effort.


There were other boats in the area and at least two (I will guess more actually) searched there too.


Too bad the seaman was not (?) leashed. A client may be inexperienced, but this is why on commercial events like this there is someone who is called the watch captain. And this person should have noted the problem.


Not saying though there was any fault on any party. Perhaps the sailor was leashed and the leash snapped.


This is sailing and at times things just go wrong. Sailing is not like sitting in an armchair (like me, now). There is always the element of unpredictability, also there when we take and make all steps as put in the best codes of practice.


When our boat got wiped out (on the same route) I was not leashed either. My own fault. The conditions looked benign. But it only took one freak wave to give me the scare of my life. And show me the complacent idiot I was.



This is also the (terrible) beauty of this sport - we can control many of the factors, but not all of them. The risk of the ultimate event is always there. Making it, perhaps, worth it. Food without spice is bland. Life without taking risks is half-life.



b.

[Dockhead]

Originally Posted by thinwater

. . . I've always liked tethers. They have their downsides too, so I understand the conflict inshore. Racing around the cans maybe it's safer to just fall in. But offshore the recovery stats are discouraging for crewed boats and worse for short handed boats.

The problem with tethers is that if you go over the rail while tethered you will die in seconds from being dragged through the water face-first. A horrible death, too.

You can mitigate this risk somewhat by running your jacklines as far inboard as you can and keeping your tethers short, but on my boat at least there are a few places on deck where you can't practically be tethered too short to go over. On smaller boats this is even worse.

This has always worried me so for many years I have carried a hooked knife in my life jacket for cutting away the tether, but I have never kidded myself that this greatly increased chances of survival -- you've got to be conscious enough for a good many seconds to grab and use the knife and blindly, and even if that works, it's out of the frying pan and into the fire as now the boat is sailing off without you.

This year I bought two of the new (costly) Spinlock lifevests that actually have a catch which you can activate by pulling a loop -- much easier than cutting away a tether -- which then flips you around to be dragged back-first, rather than face-first. If you can manage to pull the spray hood down, then I believe you might have a decent chance. IF this works the way it's supposed to, which I'm not sure is proven yet.

If we had real confidence in these AIS beacons it might actually just be better to go over untethered.

Best of all of course is to stay on the boat. As the decades go by, I have become more and more conservative about going forward in bad weather. If it just can't be avoided I usually heave-to to do it, which GREATLY reduces the risk of getting bucked off the boat, and makes it much, much easier to work on deck. I highly recommend this.

[Dockhead]

Originally Posted by davil

Originally Posted by PippaB View Post
For the AIS MOB beacon to give position it has to get a GNSS fix.

Not my understanding

An AIS signal is transmitted to an AIS receiver system by broadcasting the vessel's data, such as position, speed, and course, over designated VHF radio frequencies (channels 87B and 88B) using a dedicated AIS transponder, which essentially acts like a radio transmitter, sending out the information in a digital format at regular intervals, allowing nearby vessels equipped with AIS receivers to pick up the signal and decode the data.
Key points about AIS transmission:
Frequency:
AIS uses two VHF frequencies: 161.975 MHz (channel 87B) and 162.025 MHz (channel 88B).
Data format:
The information is encoded using a standardized digital protocol called HDLC (High-Level Data Link Control).
Transmission schedule:
Each vessel determines its own transmission slot within a predefined time frame to avoid interference with other nearby vessels.
Antenna:
A VHF antenna is required to transmit and receive AIS signals.
How an AIS receiver works:

All this is exactly correct, but one of the pieces of data transmitted in the manner you correctly describe is the AIS position report, which is derived from a GNSS fix. The GNSS receiver is built into these devices. So no, without a GNSS fix you will not transmit a position report, and AIS receivers will not know where you are.


Don't confuse AIS with 121.5mhz homing signals used in EPIRBs and PLBs for the last mile. AIS MOB beacons don't have this functionality, not in any I've ever seen. Nor does any AIS receiver I've ever seen have any ability to receive a 121.5mhz homing signal.

[Cheyne]

I just read on Yacht World another boat, Karolina Viking (Leopard 45) was abandoned on the ARC after a rudder stock begin leaking badly on the starboard side. Crew was picked up by another ARC boat. They had tried to divert to Cape Verde.

Cheyne

[Sos]

Perhaps one of the wireless systems, where you where a personnel tag, and an alarm is sounded when out of range, along with a personnel AIS would be a good system.

[carstenb]

Originally Posted by Dockhead

The problem with tethers is that if you go over the rail while tethered you will die in seconds from being dragged through the water face-first. A horrible death, too.

You can mitigate this risk somewhat by running your jacklines as far inboard as you can and keeping your tethers short, but on my boat at least there are a few places on deck where you can't practically be tethered too short to go over. On smaller boats this is even worse.

This has always worried me so for many years I have carried a hooked knife in my life jacket for cutting away the tether, but I have never kidded myself that this greatly increased chances of survival -- you've got to be conscious enough for a good many seconds to grab and use the knife and blindly, and even if that works, it's out of the frying pan and into the fire as now the boat is sailing off without you.

This year I bought two of the new (costly) Spinlock lifevests that actually have a catch which you can activate by pulling a loop -- much easier than cutting away a tether -- which then flips you around to be dragged back-first, rather than face-first. If you can manage to pull the spray hood down, then I believe you might have a decent chance. IF this works the way it's supposed to, which I'm not sure is proven yet.

If we had real confidence in these AIS beacons it might actually just be better to go over untethered.

Best of all of course is to stay on the boat. As the decades go by, I have become more and more conservative about going forward in bad weather. If it just can't be avoided I usually heave-to to do it, which GREATLY reduces the risk of getting bucked off the boat, and makes it much, much easier to work on deck. I highly recommend this.

Dockhead - we've sailed together a few times and Vinni and I have about 45,000nm under our belts the past 9 years. What you say above is correct. We don't go forward without the other person being in the cockpit. We also don't go forward without a tether. We have both PLB and AIS on our vests.

Having said all that - We are both very cognizant of the fact that if we go overboard - we will die.

Finding someone at sea is very difficult (at night let's face it, impossible) and getting that person back on board if he/she is unconscious or injured is not going to happen.

We doublehand and we know that we cannot get the other person on board alone.

I shudder when I see persons going on deck on other boats without tether or vest (we see this frequently in anchorages or when coastal sailing)