MMSI Distress Call

Tally Ho · Aug 4, 2017

Thanks Stu. Will give that a try this weekend.

Greg

Blitz · Aug 4, 2017

Scott T-Bird said:
I hear CG advising all that radio checks should be done on Channel 9 every single time that I hear a radio check on 16.

Me too, not sure why people don't use the Sea Tow automated checks on 25-29.

quadrille38 · Aug 6, 2017

bawlmer said:
We were sailing around Baltimore harbor Sunday afternoon when the VHF started screaming. I looked on the screen and it was an automated distress call. I have had a DSC radio since 2014 and this was the first time I heard it.
The alarms went off at least 5 more times. There was a note on the screen that stated "acknowledgement" but I was not sure if that triggered the following alarms. Naturally there was a lot of chatter afterwards. The distress call did not have a location attached to it and a lot of the radio chatter indicated the same thing.
The Coast Guard was immediately involved. After about 10 minutes the vessel was located visually. A catamaran capsized just north of the bay bridge and from radio traffic all were rescued. I do not know the disposition of the cat but I assumed it was righted as I heard nothing on the news. A few observations:
From the radio traffic the CG could not determine the name of the vessel from the MMSI distress call. They requested the name of the boat from the first responding vessel. That was not comforting at all.
The MMSI did not have a location attached to it. The VHF either did not have a GPS source or it was not functioning. Not having a GPS attached took a lot of the functionality out of that call and caused a tremendous amount of confusion.

One other thing of note was the range of the digital distress call was far greater than a voice call. We were behind Port Covington. The distance was about 20 miles direct and we typically do not hear voice calls from that area. If the cat in distress was on its side that is even more impressive. I do not know if it was from a HH or not. Few HH radios have MMSI.

There was a lot of confusion and even some consternation in the radio responses as no one could figure out the immediate location of the vessel in distress. One woman even yelled and told them not to send out a "SOS" if there was no emergency.

The constant repetitive distress signals captured your radio and pulled it off 16 which was where the search and rescue chatter was. That would be a problem if you were immediately involved in the SAR.

There were several soft keys that appeared on the screen when the distress call came in. I first hit "quit" when I realized this was not in my area and could not assist. The calls kept coming. I then hit "accept" but the alarms continued each time the call was repeated.

After the vessel and its crew were assisted the calls eventually stopped. I hope no one here ever had to use it. I am curious about others knowledge and experiences with MMSI distress. All input welcome.

I leaned something last week.
I have DSC radio that is 2008 vintage. In the past I've heard the distress tones followed up Coast Guard voice traffics

Well last week we were out and the boat we were sailing with got the distress tones and I did not. I did hear the coast guard follow up voice traffic. Since I've had the tones before I wondered is something had gotten turned off or if something was wrong with the radio. Pulled out the manual and could find nothing that would help.

Placed a call to ICOM. Very helpful tech support person informed me that my particular radio is a Class C VHV and that I would only hear the alert tones if I was monitoring channel 70.

The newer radios and now Class D and they apparently have a back channel that constantly monitors channel 70 in the background regardless of what channel you are monitoring or using on the front side.

He did inform me that I can send a distress call using the emergency button on the radio and that I can hear any emergency related voice traffic but that unless I'm actively monitoring channel 70 I won't hear the alerts.
I inquired whether it would work to hear the tones if I set up the tri watch to have channel 70 as the third channel being monitored. I was told that won't work because the digital data packets would get messed up trying to monitor it that way.

So solution is to live with it since the radio works perfectly fine or to buy a new radio. Going to live with it until there is a real need for a new generation radio.

jviss · Aug 7, 2017

bawlmer said:
Very Interesting. I was an ICOM dealer until about 2005. DSC was not on anyone's radar at the time. You must have one of the very first DSC radios.

I bought my Icom IC-M502, a DSC fixed-mount radio, in the year 2000.

All U Get · Aug 7, 2017

While traveling with five other boats last winter we made our own group number. Using that number we could ring five boats with one call to pass along the plan-of- the- day. Simple and quick. The number is still in the radio for this year and I can summon any from this group if they're within range.

All U Get

Jackdaw · Aug 7, 2017

Early on, there were several more classes of DSC radios. Most common (and now off the market) was a 'single receiver' DSC SC-101 where there was not a dedicated VHF reciever circuit for DSC. On these devices you would miss DSC calls if you were transmitting, and the audio on listening was broken every 3 seconds for a fraction of a second to allow the DSC to have a peek at CH70.

Modern DSC radios have a dedicated DSC receiver.

Jackdaw · Aug 7, 2017

I made this video some time ago (old radio) but it shows what a DSC call looks like from both ends.

Jackdaw · Aug 7, 2017

More fun DSC facts:

If you want to test DSC, make a DSC call to 003669999. Any USCG Rescue-21 base will give an automated response.

quadrille38 · Aug 7, 2017

bawlmer said:
Very Interesting. I was an ICOM dealer until about 2005. DSC was not on anyone's radar at the time. You must have one of the very first DSC radios.

Not really, boat was brand new in 2008 and radio was installed by the selling dealer.
Radio is am ICOM M 422. When I called ICOM tech support and gave them model number the person told me it's a class C radio.

Jackdaw · Aug 7, 2017

quadrille38 said:
Not really, boat was brand new in 2008 and radio was installed by the selling dealer.
Radio is am ICOM M 422. When I called ICOM tech support and gave them model number the person told me it's a class C radio.

Current standard for non-mandatory installs.

Jackdaw · Aug 8, 2017

bawlmer said:
We were a commercial dealer but did sell a few marine radios to our existing customers. Never had a clue about DSC back then. Must not have been paying enough attention.

Must not have! That unit that we designed with Uniden was developed in 2003.

https://forums.sailboatowners.com/index.php?threads/mmsi-distress-call.186763/page-2#post-1391315

JamesG161 · Aug 8, 2017

weinie said:
You're not my supervisor!

Perhaps...
But if you are on my boat, I am the Captain. Your safety and my boat's safety is my #1 concern.
_______
For a story on a real life event on MMSI and DSC and yes their GPS worked also, but the USCG continued to Vector on the radio call on Ch 16. to determine the ETA of the USCG rescue ASSET [USCG's term].

https://forums.sailboatowners.com//...emergency-response-great.178787/#post-1291518

______
Great discussion.

Jim...

Gunni · Aug 8, 2017

Well, that is the nature of the Rescue-21 system, it triangulates the radio transmission. Pretty amazing tech. Obviously, if I had my DSC system wired up to my GPS, had configured an MMSI, RTFM and got it to the point where it would broadcast a Lat/Lon that would be best. But I have a boat full of EPIRBs, handheld radios and there is a GPS in my ditch bag. That is the plan.

MMSI Distress Call

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SBO Weather and Forecasting Forum Jim & John

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