EPIRB PLB vs MOB Beacon

[atnan]

I have known excellent sailors who have been doing offshore for years but didn't realize it's necessary to program their MOB beacons.

Made worse by the fact that programming is a PITA on units like the MOB1. Programming via an optical strobe sensor is kinda neat in the sense that you get a fully sealed device, but browsing to a buried page on a website on your phone and holding the MOB1 just so to the screen without it turning off is a bit of an art.

My trick was using a VPN to download the different programming pages for different regions as .html files and storing them in Dropbox as offline files, so I can program anyone's MOB1 for any region without worrying about internet access on a boat.

 

[Plumbean]

[snip]
If someone is an offshore or ocean racer who does races subject to US Sailing SERs and such, then the boats are likely (but absolutely not guaranteed) to have reasonably current plotters with AIS SART capability so the PLB3 is the winner. If you're just out sailing around, you might be better off with the DSC so the MOB1 is the winner.

[snip]

Just to be clear, both the PLB3 and the MOB1 send out AIS SART messages. The distinction is that the PLB3 also sends out a 406 Mhz satellite message (EPIRB), while the MOB1 can send out a DSC distress message over VHF (limited in the US to just signaling the mother ship).

My use case is a mix of relatively near shore solo sailing and offshore crewed racing. I think it unlikely that the 406 Mhz will be my savior, so at this point I am leaning towards the MOB1 (although it annoys me that in the US you can't send out an all ships distress signal), but if I had my druthers I'd prefer to see a version of the PLB3 that also included DSC capability. I also own a Garmin InReach Mini, so I can cover off the satellite side of things by carrying that.

 

[Quickstep192]

Sorry for rolling in on this late, but I’ve been considering getting a MOB Beacon, so this is useful information.

After having read the posts in this thread a couple of times, do I correctly understand that there are no MOB devices that will send an all ships distress call in the US?

For many (I think), the best chances for rescue may not be from their own boat, depending on the experience of the crew (if there even are any crew).

If I received an all ships distress call and arrived at the boat or person who sent the distress signal, only to find that the person was OK, I don’t think I’d be too bothered.

As I debate such a purchase, it seems that a MOB device that only signals your own boat doesn’t seem terribly useful. Or at least not as useful as one that could send an all ships distress call; the latter being non-existent for the US.

Did I capture the salient points?

 

[pudge]

As I debate such a purchase, it seems that a MOB device that only signals your own boat doesn’t seem terribly useful. Or at least not as useful as one that could send an all ships distress call; the latter being non-existent for the US.

It makes it useless jumping from one boat to another without re-programming, which is a PIA.

 

[JC522]

Sorry for rolling in on this late, but I’ve been considering getting a MOB Beacon, so this is useful information.

After having read the posts in this thread a couple of times, do I correctly understand that there are no MOB devices that will send an all ships distress call in the US?

For many (I think), the best chances for rescue may not be from their own boat, depending on the experience of the crew (if there even are any crew).

If I received an all ships distress call and arrived at the boat or person who sent the distress signal, only to find that the person was OK, I don’t think I’d be too bothered.

As I debate such a purchase, it seems that a MOB device that only signals your own boat doesn’t seem terribly useful. Or at least not as useful as one that could send an all ships distress call; the latter being non-existent for the US.

Did I capture the salient points?

I'm waiting for ACR tech support to confirm whether a long press will send an all ships call. It seems that it probably does not, but they don't know and have sent an inquiry to their internal sources for clarification. Meanwhile...I recently ordered an MOB1. Maybe there is a way to test that function. I'll report if I get any new information.

 

[George Dewey]

Just to be clear, both the PLB3 and the MOB1 send out AIS SART messages. The distinction is that the PLB3 also sends out a 406 Mhz satellite message (EPIRB), while the MOB1 can send out a DSC distress message over VHF (limited in the US to just signaling the mother ship).

Yes you're right about the MOB1. MOB1 = DSC and AIS SART and PLB3 = AIS SART and EPIRB.

Concerning all ships DSC call, the MOB1 manual says it does this "where permitted" or similar language. I'm pretty sure this is not permitted in the US. But, an AIS SART is received by all boats within range, provided they are equipped with AIS receivers.

A few days ago I looked and I could not find a PLB3 for sale in the US. Pricing I saw where it was available was substantially higher than an MOB1. So, for those who want all three capabilities, it may still make the most sense to buy an MOB1 and a personal EPIRB (I have an Ocean Signal and it's tiny) or an MOB1 combined with a Garmin Inreach as others have said. In fact the Inreach might make the most sense since you can type out messages to make clear that it's not a false alert. Assuming you're conscious, but that's an issue with the personal EPRIB as well.

And to add one more question to the mix... I was under the impression that in the US at least it's not permitted for a personal EPIRB to be automatically triggered. Looking at the PLB3 manual, it was not clear to me whether the personal EPIRB functionality was automatic or not.

 

[George Dewey]

The Sea Angle device is being advertised on the main page of this website, and they put out this document comparing the various devices. The PLB3 is not on the list but this is still an interesting document:

https://www.aquaventures.net/_files/ugd/ddd36e_699cf55cad29403996be6ebfd725318d.pdf

 

[Quickstep192]

I sent an email to Ocean Signal about the MOB1 and received the reply: “All ships DSC is not available within the US for the MOB1 and it is a rule set by USCG”

 

[seaker]

I just got an email about this new PLB with AIS. It looks interesting. Based on a quick read of the manual both the PLB and AIS are preprogramed. You still have to register it with the government. But I didn't see what the message is. https://www.acrartex.com/products/resqlink-ais-personal-locator-beacon/

 

[Quickstep192]

Based on my understanding, AIS beacons in the US only show a MOB AIS on the screens of nearby boats and do not sent a distress alarm. Certain MOB beacons can send a DSC alert to only the boat from which the man is overboard.

Each seems of dubious value to me if MOB is the skipper and the crew isn’t prepared to retrieve him/her.

 

[znep]

Based on my understanding, AIS beacons in the US only show a MOB AIS on the screens of nearby boats and do not sent a distress alarm. Certain MOB beacons can send a DSC alert to only the boat from which the man is overboard.

Each seems of dubious value to me if MOB is the skipper and the crew isn’t prepared to retrieve him/her.

In the coastal and near coastal cases, more and more areas have VHF high sites that are also equipped so the coast guard can monitor AIS transmissions, largely for tracking commercial traffic but also for SAR. Even if you entirely discount the AIS for alerting of the MOB, once the alert is raised (satellite, VHF voice, etc) the AIS signal is invaluable for responding pleasure, commercial and SAR vessels/aircraft in the area to cut down the search time while the clock is ticking.

Range is going to be an issue being so close to the water with minimal power, especially for other vessels (as opposed to high sites) and in rough seas.

In your example, if the crew can't retrieve the skipper for some reason then either they can make a mayday call. The point of the AIS signal is then to pinpoint the location for responding assets. It seems a lot more likely that responders, especially non-professional ones, will be able to zero in on an AIS signal than a DSC transmission as they are more likely to use AIS on a day to day basis.

A 406 MHz PLB satellite "EPIRB" + AIS SART sounds like a great alert + locate combination to me. Wouldn't want to mess around with all the ugly DSC stuff described in this thread.

The handling of AIS SART transmissions isn't great on many receivers/nav systems but that will improve over time and is something to test on any boat you might use one on.

From https://www.dco.uscg.mil/Portals/9/CG-5R/manuals/COMDTINST M16130.2F.pdf :

AIS Search and Rescue Transmitter (AIS-SART). The AIS-Search and Rescue Transmitter is a portable manual-deployment survivor locating device intended for use on life rafts or survival craft and is an alternative to a radar SART. AIS SARTs are also used for personal locator beacons and man-overboard devices. The type of device used and an indication whether the transmission was active, or a test is transmitted as a safety related (text) message. As with radar SARTs, AIS SARTs are not intended as distress alerting devices, but rather as distress locating devices. The device sends updated position reports using a standard AIS class A position report. It has a built-in GNSS receiver.

 

[JC522]

From Ocean Signal customer support:

"If you configure your MOB1 an MMSI it will then allow you to add a group MMSI. If the MOB1 is activated the AIS and DSC functions will both activate.

AIS will send a signal to all ships within range

The DSC will send a signal to only the ship with the MMSI entered onto the device.

Please note that the group call is only sent after a period of 30 minutes.

The group MMSI will send a DSC alert to all ships with the group MMSI within range (5 nautical miles depending on weather, location of antenna ect.)

All ships DSC is not available within the US for the MOB1 and it is a rule set by USCG."

 

[inneedofadvice]

All ships DSC is not available within the US for the MOB1 and it is a rule set by USCG."

Must be some reasoning behind this. Any thoughts on what that might be?

 

[znep]

Must be some reasoning behind this. Any thoughts on what that might be?

Endless invasive false alarms due to user error / equipment design that result in folks turning off their VHF entirely to escape them.

 

[seaker]

I sent an email to Ocean Signal about the MOB1 and received the reply: “All ships DSC is not available within the US for the MOB1 and it is a rule set by USCG”

I wonder if that will be true for the new ACR ResQLink AIS? It doesn't seem like it is registered to your boat as an AIS transmitter. And they say it's the first beacon that combines PLB and AIS. "The combination of 406 MHz and AIS distress messaging pairs both global and local rescue into one beacon for the first time, extending access to the Coast Guard and Search and Rescue as well as commercial and recreational boats in the area. Alerting local AIS equipped boats in your vicinity allows for additional vessels to respond directly to the digital mayday with your precise location."

 

[atnan]

I wonder if that will be true for the new ACR ResQLink AIS? It doesn't seem like it is registered to your boat as an AIS transmitter.

The ACR ResQLink AIS doesn’t support any form of DSC. I’d imagine it would behave near-identically to the MOB1 from an AIS perspective.

 

[Israel Hands]

I've muddled through this thread, and concluded that for offshore Atlantic sailing I probably should get the MOB1 for the admiral and me.

Here are a couple of practical questions since I've never owned or worn an MOB. Will it fit in most PFD/harnesses? Also, other than triggering by accidental PFD inflation, are there other ways to accidentally trigger it? Or is it relatively easy to arm and one can expect it to perform as desired?

 

[JC522]

After all this BS I finally bought the MOB1, and I found a very simple hack. Ocean Signal leaves it to the owner to tell the device what country it's in!

When you go to the Configuration Installer software web page (oceansignal.com/installers), there are versions you can download for different countries. The US version of the installer will not enable "automatic activation of Distress alerting". The Australia, New Zealand, and DEFAULT versions will. I.E., those last 3 will program the MOB1 so that upon activation it will automatically send a DSC All Ships Distress alert.

I'm in the US. I used the Default installer instead of the US installer. It worked well, allowed me to check the boxes to fully enable DSC, and did not ask me to enter a series of MMSI numbers to establish a Group, as the US version of the installer would have.

Hint: Turn off Location Services on your PC (as instructed) and use the brightest monitor screen that you can find.

Good luck.

 

[Quickstep192]

After all this BS I finally bought the MOB1, and I found a very simple hack. Ocean Signal leaves it to the owner to tell the device what country it's in! I expected something more sophiticated like using the MMSI number, or Location Services, or maybe preprogramming the unit with country info.

When you go to the Configuration Installer software web page, there are versions you can download for different countries. The US version of the installer will not enable "automatic activation of Distress alerting". The Australia, New Zealand, and DEFAULT versions will. I.E., those last 3 will program the MOB1 so that upon activation it will automatically send a DSC All Ships Distress alert.

I'm in the US. I used the Default installer instead of the US installer. It worked well and did not ask me to enter a series of MMSI numbers to establish a Group, as the US version of the installer would have.

Hint: Turn off Location Services on your PC (as instructed) and use the brightest monitor screen that you can find.

Good luck.

Why the brightest monitor?

 

[JC522]

MOB1 is programmed by a series of light pulses. You download the app, put MOB1 in programming mode, hold it up to the monitor and press go.