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MMSI question for MOB transponder, need fast answer

Aug 22, 2017
1,608
Hunter 26.5 West Palm Beach
A friend of mine is about to start an international trip on a sailboat. The friend is being required to bring one of these personal AIS transponders - https://www.westmarine.com/buy/ocean-signal--rescueme-mob1-ais-dsc-personal-locator-beacon--16749251?mrkgcl=481&mrkgadid=3076579456&cm_mmc=PS-_-Google-_-GSC>NonB>Product%20Type-_-16749251&product_id=16749251&adpos=1o3&creative=108421552804&device=c&matchtype=&network=g&gclid=EAIaIQobChMIsc7qwcDR3gIVzODICh1FzA_yEAQYAyABEgIU1_D_BwE

The person is being advised to enter the mother ship's MMSI into the personal AIS stick. I understand that normally, all devices on a given ship should use the same MMSI, but in this situation, that doesn't sound right to me. I am concerned that the chart plotter on the mother ship may not identify a copy of it's own MMSI as a separate entity in the water. I am further concerned that if a rescue boat were in the area, it would see 2 mother ships on its chart plotter & not know which is the MOB.

Does anyone have experience with this? Does anyone know what is correct?
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Good question, but this is a safety item and questions about the technology can, and should be answered by the manufacturer. In any case, I would not rely on a VHF-based device in lieu of a PLB sat signal locator. Have both.
 
Jan 11, 2014
7,849
Sabre 362 113 Fair Haven, NY
The signal sent by the AIS based MOB device is different in that it sends an emergency notice that the AIS receivers will recognize and highlight.

What I don't know is whether the devices are reprogrammable by the user. Might want to contact the manufacturer about that.
 
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May 20, 2016
2,992
Catalina 36 MK1 94 Everett, WA
New AIS had problems reporting their own MMSI. New ones don’t have the problem. You should test any PLB after flashing. And the PLB I have can reset the MMSI many times unlike the AIS itself.

@Gunni I have budget and space for only one PLB. I chose AIS over EPERB because in the water I sail in I’d be dead before a rescue via Satellite could happen, maybe if I was offshore, or sparsely traveled waters it would make sense.

Many boats around here are at least AIS receiver capable, including my own improving the chanc I’ll be found.

Les
 
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Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Just as an FYI, my AIS is a stand-alone system, does not share anything with the ships radio. Both my AIS and my ship's radio have their own MMSI. Both were procured from BoatUS, which I have been told is not proper for international travel, but they work non-the-less.
 
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Dec 23, 2016
184
Catalina 27 Clinton CT
Your friend needs to contact the FCC for a station license to cover int waters. MMSI is only good for US waterways. Understand to reprogram it again, it will have to go back to the factory at a charge
 
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Jan 11, 2014
7,849
Sabre 362 113 Fair Haven, NY
Just as an FYI, my AIS is a stand-alone system, does not share anything with the ships radio. Both my AIS and my ship's radio have their own MMSI. Both were procured from BoatUS, which I have been told is not proper for international travel, but they work non-the-less.
Yes the BoatUS MMSI numbers are not valid for international travel, including Mexico, Canada, and the Bahamas. In order to use a radio outside of the US an FCC Ship's Station License is necessary and an appropriate Radio Operator's license is necessary. Most use the Restricted Radio Operator License. The Ships Station License will assign a MMSI number for the vessel.

I believe the MMSI is assigned to the vessel not the radio.

The big advantage to the AIS based MOB is immediate notification to the vessel that is in the best place to affect a rescue, i.e., the boat you just fell off of. Additionally any vessel with AIS within about 5 miles will see the signal. The AIS will also provide directions to get to the MOB.

John Harries just published last week. Worth the read if you have one of the affected units. https://www.morganscloud.com/2018/1...lure-of-the-mob1-ais-person-overboard-beacon/
 
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Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
And the PLB I have can reset the MMSI many times unlike the AIS itself.
Leslie; PLB's do not have an MMSI. This thing that Jim is referring to is NOT a PLB.
I chose AIS over EPERB because in the water I sail in I’d be dead before a rescue via Satellite could happen
You might also be dead if your crew (or nearby crews) are not monitoring AIS before you go a few miles downrange and out of signal range. PLBs and EPIRBs light up a professional SARSAT organization, they will confirm your float plan with your contact and broadcast a notice to mariners that you have declared an emergency. This all begins within 15 minutes.

One of the great things about a PLB is you can carry it anywhere and call in the cavalry. You don't need a boat, you don't need a VHF, you don't need competent crew. Land, Sea, Air.
 
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May 20, 2016
2,992
Catalina 36 MK1 94 Everett, WA
Your friend needs to contact the FCC for a station license to cover int waters. MMSI is only good for US waterways. Understand to reprogram it again, it will have to go back to the factory at a charge
Nope - An AIS based PLB according to the instruction manual uses the MMSI of the mother ship which should have a station license and a MMSI appropriate for the water your. Traveling it. PLB do not need to be sent to the Mfg. for resetting the MMSI, mine has a web page that you enter the New MMSI and it optically flashes the PLB with the new number. The way the OP described is exactly the way the instruction with the PLB state they should be used.

Canadian CG WILL respond to a BoatUS AIS distress call. They won’t have boat name,size (color??) which may make rescue harder. They can not also phone your contact person to let them know your in trouble.
 
Dec 23, 2016
184
Catalina 27 Clinton CT
My Mistake, should have clicked on the link. This is a PLB . From the Manual:


4. MMSI configuration


If your vessel has a DSC enabled VHF radiotelephone, it is strongly recommended to

programme your vessels MMSI number into your MOB1. This will allow the MOB1 to send

the details of the man over board incident direct to the radio and sound the alarm.

4.1 Self Identification

The MOB1 is supplied with the self identification number pre programmed. This number is

specific to each MOB1 and cannot be changed. The MMSI displayed on the DSC receiver

will always start with ‘972’ irrespective of the country it was purchased in.

4.2 User MMSI

(Applies to DSC enabled units only)

To be able to send DSC messages to your vessel, the MMSI number of the vessel needs to

be programmed into the MOB1. This is achieved using a PC based applicatio
 
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May 20, 2016
2,992
Catalina 36 MK1 94 Everett, WA
Leslie; PLB's do not have an MMSI. This thing that Jim is referring to is NOT a PLB.

You might also be dead if your crew (or nearby crews) are not monitoring AIS before you go a few miles downrange and out of signal range. PLBs and EPIRBs light up a professional SARSAT organization, they will confirm your float plan with your contact and broadcast a notice to mariners that you have declared an emergency. This all begins within 15 minutes.

One of the great things about a PLB is you can carry it anywhere and call in the cavalry. You don't need a boat, you don't need a VHF, you don't need competent crew. Land, Sea, Air.
@Gunni I respectfully disagree. Go re read the OP. He is talking about a AIS based PLB, and yes the do have a MMSI associated. If I fall over with an EPRB based PLB - my crew has absolutely no idea where I’m at until the get contacted by authorities with my GPS location.

If I fall over with a AIS based PLB my crew will get an alarm on my station VHF, the handheld (assuming I don’t hav it on me) and My chart plotter and each of my I70 displays, showing my exact location and distance.

I know which one is going to get me out of the water quicker!!!!!

Les
 
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Aug 22, 2017
1,608
Hunter 26.5 West Palm Beach
Thank you to everyone who replied.
Much useful info was provided.
I appreciate the help.
 
Aug 22, 2017
1,608
Hunter 26.5 West Palm Beach
Just a little follow up here, in case anyone else runs into this situation -

ACR sells two different versions of these things. They are the Rescueme MOB1 (which may actually be made by Ocean Signal, judging by the manual I downloaded) & the AISlinkMOB, which is their traditional colors & may actually be made by them, or may be a better brand labeling job. Both are roughly the same price. Both use the same type of computer software to enter a User MMSI #. Apparently, other companies make similar devices too. This is a link to a webpage that compares some of them - https://www.panbo.com/testing-ais-mob-beacons-acr-dsc/

Below is an excerpt from the ACR manual that applies to my original question. I'm still not 100% sold on using the boat's MMSI number in the MOB unit, but that seems to be what they recommend. I am also still not clear on the difference between the User MMSI & the pre-programmed "self identification number" that can't be changed. I did not find a reference that tells me if you can change the user MMSI number multiple times or not. The spec sheets for both the ACR units say that the units put out 1 watt for AIS & 1/2 watt for DSC. This combined with a small antenna that will likely be below wave height, should add up to a very limited range. They warn against testing the unit more than a few times per year to prevent depleting the battery. If the unit is used one time, even for a short time, the battery must be replaces at a factory authorized facility. Shelf life is said to be 7 years.


Excerpt from manual:
4. MMSI configuration
If your vessel has a DSC enabled VHF radiotelephone, it is strongly recommended to
programme your vessels MMSI number into your MOB1. This will allow the MOB1 to send
the details of the man over board incident direct to the radio and sound the alarm.
4.1 Self Identification
The MOB1 is supplied with the self identification number pre programmed. This number is
specific to each MOB1 and cannot be changed. The MMSI displayed on the DSC receiver
will always start with ‘972’ irrespective of the country it was purchased in.
4.2 User MMSI
(Applies to DSC enabled units only)
To be able to send DSC messages to your vessel, the MMSI number of the vessel needs to
be programmed into the MOB1. This is achieved using a PC based application and its
display screen.
4.2.1 Installation
The programming software for configuring the User MMSI into the MOB1 can be
downloaded from www.oceansignal.com/installers. The version downloaded will only allow
the DSC options available in your country. Some functions described below may not be
available to you.
Save the file to your computer and open it to run the installer. Follow the instructions on
screen.
4.2.2 Configuration
Run the application from the desktop icon. The screen
shown here will appear.
Enter the nine digit MMSI of the vessel in the box provided
and select update beacon.
(In the USA, after the MMSI has been entered, a second box for a
group MMSI will appear. Enter your group MMSI here if applicable,
noting that group MMSI numbers should always start with a zero.)
On completion press the Update Device button to proceed.
A new screen with further instructions will appear.
To put the MOB1 into programming mode, slide the Arming
Slide down to the armed position and press the TEST/OFF
Key for at least fifteen seconds. The LED will start flashing
green. Release the key.
 
Jan 24, 2013
33
Hunter e36 Norfolk
I'm still not 100% sold on using the boat's MMSI number in the MOB unit, but that seems to be what they recommend. I am also still not clear on the difference between the User MMSI & the pre-programmed "self identification number" that can't be changed.
The reason you program the boat's MMSI in the MOB unit is because that is the MMSI that it CALLS via DSC if you fall overboard. This is re-programmable in case you are on a different boat. The other number is fixed and identifies the sending unit to any vessel within VHF range (limited by the weak vhf power and obviously low antenna height)

Calling via DSC allows the unit to proactively alert the vessel audibly that you have gone overboard. Once you program the unit you can test the DSC calling.

I have the MOB-1 unit and it worked well in testing. I fortunately have not had ocassion to see it in real life action.
I agree with the idea that I would rather have my boat (and other boats - if any - nearby) know where I am as opposed to a satellite operator hundreds of miles away.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
There is zero confusion regarding what happens next with a satellite SARSAT device. None. Just saying.

So what DOES happen with this AIS thing and it’s duplicate MMSI when the Chinese fire drill begins? It calls your boat? What if you are singlehanding? What if mom is sleeping? What if everyone on board went overboard?

Suppose it triggers a DSC rodeo: Does the radio light up with the usual cast of characters asking for radio checks who somehow figure out that an emergency situation is ongoing and it involves your sailboat...and yes, it appears that your boat is motoring just fine? Does the USCG get involved, asking that all mariners be on the lookout for your 23’ vessel with leopard-skin topsides which has declared an emergency? What happens then? Does a radio committee form up ad hoc, would anyone have a clue that this isn’t a boat emergency, it is a MOB emergency? Suppose the radio committee had no AIS capability. Suppose the radio response committee had a ships radio with some add-on AIS screen with blinking dots. Remember, these are the radio-check guys, this is the modern USCG watchstander service model, and this is DIY rescue.
 
May 20, 2016
2,992
Catalina 36 MK1 94 Everett, WA
There is zero confusion regarding what happens next with a satellite SARSAT device. None. Just saying.

So what DOES happen with this AIS thing and it’s duplicate MMSI when the Chinese fire drill begins? It calls your boat? What if you are singlehanding? What if mom is sleeping? What if everyone on board went overboard?
[\QUOTE]
As stated above yes it calls my boat and all stations in VHF range of you boat (not the short antenna range of the guy in the water) and notifies them via DSC that there is a MOB.
Suppose it triggers a DSC rodeo: Does the radio light up with the usual cast of characters asking for radio checks who somehow figure out that an emergency situation is ongoing and it involves your sailboat...and yes, it appears that your boat is motoring just fine? [\QUOTE]
No DSC comes out wit the GPS coordinates of the MOB. They don’t know if your a sail or power boat. If the can see the boat motoring the are in a position to render aid and I believe legally required to. [\QUOTE]
Does the USCG get involved, asking that all mariners be on the lookout for your 23’ vessel with leopard-skin topsides which has declared an emergency? [\QUOTE]
To my knowledge yes the USGG does get involved and will manage like any emergency. With full knowledge it’s a MOB situation. The know which boat to hail because of the MMSI and can call using DSC.
What happens then? Does a radio committee form up ad hoc, would anyone have a clue that this isn’t a boat emergency, it is a MOB emergency? Suppose the radio committee had no AIS capability. Suppose the radio response committee had a ships radio with some add-on AIS screen with blinking dots. Remember, these are the radio-check guys, this is the modern USCG watchstander service model, and this is DIY rescue
.
Now your being ridiculous. Unless the world is populated with Luddites the blinking dot on the AIS shows up on the chart plotter, and can render Aid. And yes I’m aware of your views on networking equipment and don’t agree with your conclusions.
 
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Aug 22, 2017
1,608
Hunter 26.5 West Palm Beach
There is zero confusion regarding what happens next with a satellite SARSAT device. None. Just saying...
That statement is not consistent with several things that I have read. That having been said, I have no first hand experience activating one, so by definition, I base my concerns on hearsay. I do have concerns though. One concern is the number of documented equipment failures. A second concern is reports of some foreign jurisdictions (banana republics) choosing not to respond when notified that a distress beacon signal has been received. My greatest concern is based on reports of the guys at the emergency desk sitting on information because when they called the contact person listed on the Epirb profile, they did not get a response.

My confidence in Epirb response is not as strong as yours seems to be. I know who is sailing on my boat with me & in many cases, they are the first people that I want to try to find me if I am MOB. When someone has gone MOB from my boat, I have always gotten them back on board myself. Perhaps your situation is different.

Some casual reading to spark further consideration -
http://www.ybw.com/forums/showthread.php?392424-PLB-Response-Time
https://www.rte.ie/news/2013/1122/488335-epirbs/
https://www.atsb.gov.au/media/4126629/ar-2012-128_final.pdf
http://www.webring.org/l/rd?ring=skywarn;id=5;url=http://robinstorm.blogspot.com/2007/07/webexclusive-epirbs-and-sv-sean-seamour.html
https://gcaptain.com/epirbs-failure-the-investigation-continues/
https://www.sail-world.com/Australi...fter-capsize-off-Brazil/-118751?source=google
http://www.cruisersforum.com/forums...appens-how-to-improve-rescue-odds-146617.html
https://www.boatus.org/epirb/work/
 
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