MMSI Numbers

The Voyage Data Recorder will record VHF conversations for a limited period of time, but only on the channel the VHF is set to. If its on Ch16, it will only record that. DSC contacts are not recorded on the VDR.

Roberto said:
Have used the DSC routine call several times towards ships, when I had doubts about their intentions, I haven t counted but say 20-30times, I usually input ch72 instead of the usual 06 which is more likely to be busy, they *always* replied. Very personal statistics of course, but surely I will continue using this system when need be.
Also, I think the call is automatically logged on the voyage recorder, should they not reply to DSC, I suspect a voice call on 16 with their name/MMSI and the wording "collision course" would probably awaken anyone except some very low standard crew ships; though I have never had the need to do so.
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Chris Edwards said:
The Voyage Data Recorder will record VHF conversations for a limited period of time, but only on the channel the VHF is set to. If its on Ch16, it will only record that. DSC contacts are not recorded on the VDR.
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Presumably the bridge microphones (are they fitted on all VDRs or only some?) would pick up the alarm sound, though.

Pete
 
Living in this rather delightful backwater and sheltered from the real world has left me, and the others here, behind in the world of marine communications. Though we might know what DSC is for and what it can do - we simply don't use nor need it. Yes - we know we can press the alarm - but an EPIRB, which we must carry when sailing offshore (which means leaving sheltered waters) will be received with much more reliability than a DSC distress (generated on VHF).

When we transit the coast there might be 5 other yachts within VHF range and possibly an equal number of commercial vessels. The commercial vessels tend to stay a bit further offshore than yachts - so there is little danger - until they come to port (and then there should still be little danger).

Our MMSI number is logged along with our mobile phone numbers, what communication equipment we have on board VHF/HF with Marine Rescue but they have never once used the MMSI number (preferring VHF Ch16) - DSC might be used by others - as has been said how would you know.

I can see from the replies people do use MMSI numbers (and DSC) but there is hardly an overwhelming number of replies and certainly not the fervour of the thread on Radar vs AIS. I, maybe wrongly, get the impression - people know its there but really don't use it much.

Its major application, the MMSI number, is the need to input the number in order to 'switch on' an AIS transmission - which does seem invaluable in areas of high numbers of fast moving vessels, Dover, Hong Kong, Singapore etc but (AIS) is much less necessary (but admittedly might be nice) in areas where commercial shipping is less frequent - on the assumption you do keep watch (which is necessary for those small vessels anyway).

Today I am much more likely to be surprised by a small commercial fishing boat or runabout, who will not have AIS. We would normally know, because they will have logged into Marine Rescue, other yachts transiting, they will be monitoring Ch 16 and there is little VHF traffic. Large commercial vessels will be monitoring VHF, at least when the come inshore, because Port Control use Ch 16 to open communications with them - advising to anchor, Pilot will arrive by helicopter etc - so essential they monitor.

Basically DSC has passed us by. But nice to know that technology does find use with some in other areas. Thank you for the lessons on communication in the 21st Century!

I had wondered how the MMSI number related to country of registry, or not - my guess was right - but nice to have that confirmed (thanks)

If ever Australia joins the rest of the world (or some parts of it) I can see the need for some refresher courses :)

Jonathan
 
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Good point.

Possibly although I recall Class A kit doesnt change channel automatically. Dont recall it doing that.

ETA - Class A VHF DSC kit allows the operator to choose in settings for non distress calls. The unit will either automatically switch to the proposed working channel or stay as it is, requiring the operator to manually select the proposed channel.
I suspect most bridge watch officers would go for the latter. Nothing more infuriating than trying to monitor VTS on 14 and having your VHF flipping to some obscure intership channel in the middle of reception of something important.

awol said:
But one point of DSC calls is that they change the channel of the receiver so presumably there will be a recording. It's a feature I find annoying, having to reset the box after a CG all-ships call.
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Neeves said:
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If ever Australia joins the rest of the world (or some parts of it) I can see the need for some refresher courses :)

Jonathan
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It's not only you guys that have failed to notice it - there are plenty round here who are either unaware of it or refuse to use it. There seem to be two groups (classes) of sailor round here - the technophiles and the technophobes. I'm definitely a technophile - I want the latest gear and use it as much as possible. Perhaps I'm just a nosey buggar - I often keep the radio on while in port just to hear what others are doing. The technophobes hate having any electronics turned on and claim to switch the VHF off completely as soon as they have got under way.
 
Chris Edwards said:
As mentioned earlier in the thread, the VDR records sent and received audio from the VHF but only on the channel being used on the VHF at the time.
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Excellent thanks,
so 1st dsc call, if they do not reply to dsc then ch16 voice call(s), if still no answer then they probably are sub-standard crewed ships, no listening watch on ch16, no double watch etc so one has to make do.
As I said I may have been lucky but always got replies from ships to individual dsc calls, which to me it's one of the advantages of MMSI, with other types of traffic like Korean/Chinese fishing boats drifting in the middle of the ocean, others that using white strobes to signal themselves from time to time, or 20-30m long wooden pirogues, etc I often do not even bother calling, dsc or voice, I guess they are second category :)
regards r
 
"I can see from the replies people do use MMSI numbers (and DSC) but there is hardly an overwhelming number of replies and certainly not the fervour of the thread on Radar vs AIS. I, maybe wrongly, get the impression - people know its there but really don't use it much."



Probably about right, in my experience.
 
I think people also need to know if you are incapacitated on your boat , cant speak ,etc, pressing the DSC distress button with MMSI number gives the authorities your boat , name , class, normally how many on board GPS location, yes rare that a person can not talk but if knocked unconscious and very groggy going in and out of unconscious , pressing a button and knowing that all that information is sent to the rescue services is a great piece of mind. (sorry pun)
 
moomba said:
I think people also need to know if you are incapacitated on your boat , cant speak ,etc, pressing the DSC distress button with MMSI number gives the authorities your boat , name , class, normally how many on board GPS location, yes rare that a person can not talk but if knocked unconscious and very groggy going in and out of unconscious , pressing a button and knowing that all that information is sent to the rescue services is a great piece of mind. (sorry pun)
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How does it know how many people on board?
 
We use DSC/MMSI to directly call friends especially in a rally.

But more importantly, now ships do not need to keep a watch on Ch 16, it is the best way to call a ship. It doesn't matter what channel they are listening on nor if they have turned their VHF down; it alerts them. And in the channel we have found it more effective than a call on 16.
 
Little Grebe said:
How does it know how many people on board?
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When you apply for your number you give them an estimate to the max people on board so if you always sail single handed you you put 1 , just you and your partner 2, every now and then with friends like me I put max 4 , never fully accurate but gives the rescue authorities something to go along with.
 
doug748 said:
"I can see from the replies people do use MMSI numbers (and DSC) but there is hardly an overwhelming number of replies and certainly not the fervour of the thread on Radar vs AIS. I, maybe wrongly, get the impression - people know its there but really don't use it much."



Probably about right, in my experience.
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Me too. One significant advantage of learning to use it is that your radio is still operational when there is a seelonce in place.
 
Sandy said:
You have hit it on the head Jonathan, it is not used as much as it could be. My degree is in digital communications (everything from ultra low frequency underwater transmissions to satellites via radio/TV and the the internet) so I am a bit bias in using a technology that is available and free. I rarely use CH16 as I've no need to unless I am hailing a vessel I don't have the details for.

Totally agree about the AIS, but it has come from the shipping world. If you have time there is a YouTube video about the early development of AIS and its use - basically for tracking big ships for overt and covert reasons. Spent an afternoon in a French Semaphore Station (a bit like a manned Coastguard Station) and spoke to them how they use it. A ship enters French waters and the AIS marker is linked to the ship and its cargo manifest. If there is ever a problem they know exactly what is on it and can track from entering to departing French waters, utter brilliance.

Lots of leisure sailors think AIS is the bees knees and will save them from impending disaster, it won't. It will tell them what is where and if you both remain on the current course and speed you, theoretically, will collide - I usually have at least one set of Mark I eyeballs onboard who will do that far faster than any electronics, but do worry about the reliance on electronics on solving every problem by the majority of leisure sailors, pop a way point here and go to that and another one there and go to that. problem is when five other vessels do the same thing and everybody is not paying attention to what is around them.

Perhaps because I understand the maths behind getting a signal to a GPS receiver and how easy it is to get it wrong only use GPS as a backup to doing it the old fashioned way with paper and pencil.
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You may be a clever chap, but you were still rude to our Antipodean cuz! :)
 
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