Mayday - MMSI and Position

capnsensible said:
Why would it be an RYA invention?

The directives are merely implemented into RYA training so everyone has the option to understand it.
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The RYA has form for teaching on radio courses stuff which they think would be nice but which isn't actually in the rules. We had a discussion about this fairly recently. When I did my VHF course, many years ago, the RYA was teaching that Mayday was for "person or vessel in grave and imminent danger" though "or person" had not at that time been added to the rules. The Marconi man who examined me was adamant that a man overboard was NOT enough for a Mayday call, though I am sure that if it had happened I'd have made the call and taken the consequences.

The official rules, by the way, are clear that the MMSI need only be given if the original alert has been sent by DSC (http://life.itu.int/radioclub/rr/chapt-7.pdf, 32.13C & 32.13D, p 314). Perhaps the RYA makes that clear.
 
See http://life.itu.int/radioclub/rr/chapt-7.pdf - the "bible" in these matters.

"32.13C § 9B 1) The distress call sent on the frequency 156.8 MHz (VHF channel 16)
shall be given in the following form:
– the distress signal MAYDAY, spoken three times;
– the words THIS IS;
– the name of the vessel in distress, spoken three times;
– the call sign or other identification;
– the MMSI (if the initial alert has been sent by DSC). (WRC-07)
32.13D 2) The distress message which follows the distress call should be given in
the following form:
– the distress signal MAYDAY;
– the name of the vessel in distress;
– the call sign or other identification;
– the MMSI (if the initial alert has been sent by DSC);
– the position, given as the latitude and longitude, or if the latitude and
longitude are not known or if time is insufficient, in relation to a known
geographical location;
– the nature of the distress;
– the kind of assistance required;
– any other useful information. (WRC-07)
 
We may all have different opinions and reasons for what we might do in a real situation but for the OP who is going to sit an exam on the correct procedure - this is it.

Article 32, page 81 paras 32.13C and 32.13D show the correct form of sending a Mayday call and message as required by International Regulations.

http://www.itu.int/dms_pub/itu-s/oth/02/01/S020100002C4006PDFE.PDF


- edited to add "Thistle" beat me to it whilst I was typing :)
 
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And just to be completely anal about it, it was discussed here too - http://www.ybw.com/forums/showthread.php?296151-Changes-to-Mayday-call which includes a useful link to the ITU document that specifies exactly how the call should be made.

Does it matter? Probably not if the call is answered by a CG since they have the knowledge to ask the right questions.

Is the call likely to be word perfect? Probably not since when you're up to your in **** then getting the procedure right appears to slip from one's mind.

Do you need to get it right for the SRC exam? Yes, if you want to ensure you pass, although a couple of small mistakes can be made so long as you get the rest of the questions right in part A of the paper.
 
Elessar said:
None are a reason to repeat such a long number. Your call sign, memorable by a human, would do the same thing. So would just the last 3 digits of the MMSI, also memorable by a human.

Answer to the OP. Because the process was designed by committee.
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Does the DSC put out the callsign? I think it only puts out the MMSI. And I would have thought the last 3 digits would be repeated with the number of MMSI numbers issued?

I think what we have is an international system for commercial vessels and it is hard for the average leisure boater to see how the system suits them - bottom line is it wasn't set up with us in mind and we have to adapt to the system rather than the system being able to adapt to us...
 
l'escargot said:
Does the DSC put out the callsign? I think it only puts out the MMSI. And I would have thought the last 3 digits would be repeated with the number of MMSI numbers issued?

I think what we have is an international system for commercial vessels and it is hard for the average leisure boater to see how the system suits them - bottom line is it wasn't set up with us in mind and we have to adapt to the system rather than the system being able to adapt to us...
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Call sign on same database.
Chances of confusing a dsc and voice call slim. Use last 3 digits of mmsi and it is 1000 times less likely. Good enough.
 
Elessar said:
Call sign on same database.
Chances of confusing a dsc and voice call slim. Use last 3 digits of mmsi and it is 1000 times less likely. Good enough.
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You're assuming there is a database. You're working with probabilities not certainties. And the only reason we have trouble with MMSI numbers is because we don't habitually use them (phone numbers are just as long but we cope with them - and if you call 999 you will be asked for your number even though it's on the operators screen for similar reasons)
 
JumbleDuck said:
The official rules, by the way, are clear that the MMSI need only be given if the original alert has been sent by DSC (http://life.itu.int/radioclub/rr/chapt-7.pdf, 32.13C & 32.13D, p 314). Perhaps the RYA makes that clear.
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Well seeing as you will only have an mmsi if you have a DSC set, and to not press the button in a real situation would be bonkers, I classify that observation as 'obvious'. :)

Some years ago I knew a SR pilot at Lee on Solent. He strongly recommended that, as going late to a MOB incident invariably resulted in corpse recovery, a prompt MAYDAY call was the correct action.

Hope this helps!
 
I go back to my earlier post. The format is as it is because it does several things at the same time. It helps the person in distress to focus on the information needed: who you are, where you are and what the problem is. The call sign and MMSI are part of who you are: it's no use giving the last three digits of your MMSI if you're talking to a Greek CG radio operator or Philipino bridge watch keeper. He'll be after the whole number because that's how, with limited English, he's been trained, and it's those sort of people the system has been designed to help.

All of that said, on the two occasions I've had to make PAN PAN calls, in UK waters, I never mentioned the call sign or the MMSI as I wasn't sorted enough to have them to hand. In neither instance did the CG refuse to deal with me, it just took a bit longer to establish who I was. Nor would I expect an overseas CG to be any less helpful, having listened in to Greek CG exchanges in response to MAYDAY and PAN PAN calls, none of which were models of correct procedure on behalf of the distressed vessel....
 
Erbas said:
You're assuming there is a database. You're working with probabilities not certainties. And the only reason we have trouble with MMSI numbers is because we don't habitually use them (phone numbers are just as long but we cope with them - and if you call 999 you will be asked for your number even though it's on the operators screen for similar reasons)
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you miss the point, I can remember my phone number I can't remember my MMSI. If you don't want to rely on the database the last 3 digits of the MMSI will do just fine.
 
Camelia said:
Now we are in the new world of one Coastguard "call centre" I am very, very uneasy about giving anything but a lat and long.
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Well in the middle on nowhere that's fine. Down here you are more likely to be helped by a fellow boater if they know you are in trouble, so transmitting your position in a useful format is best. You have already transmitted lat/long to the CG with your red button.
 
Elessar said:
you miss the point, I can remember my phone number I can't remember my MMSI. If you don't want to rely on the database the last 3 digits of the MMSI will do just fine.
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Will do just fine for what? It's just three abritrary, ambiguous and ultimately meaningless numbers

It would still leave anyone needing to link the DSC distress call with the subsequent voice communications unable to say with absolute certainty that the two communcations are related to the same incident

Oh it might "do just fine" on a quiet day in the Solent (does such a thing ever happen?) twixt thee and the all singing, all dancing, brand new Coastguard coordination centre with its highly skilled, well trained and experienced operative but can you, hand on heart, guarantee with absolute total and utter certainty that it will "do just fine" in the Maldives, or Corsica, or the Antarctic, or in the Red Sea, or via an HF call from the middle of the South Atlantic or where the initial DSC Mayday is followed up with a satellite phone call or ...

The procedure is as it is because professional mariners and professional radio operators sat down professionally and worked out the clearest and most un-ambiguous procedure that works in any conceivable circumstance. That some leisure sailors cannot deal with a 10 digit number once in a while was not, I suspect, a consideration.

PS. Really the problem is the almost universal, and I include myself in this, failure to take up DSC as a routine part of VHF comms. This I suspect is partly because lesisure sailors, myself included, do not use the VHF all that much and partly because the DSC functions on marine VHF sets are badly implemented and both time consuming and difficult to use. If we were used to using our MMSI number on a regular basis it wouldn't seem at all odd or awkward to need to quote it duing a Mayday
 
There's good reason to using the procedure, and using it exactly as written, even when it might seem cumbersome: It's what the people at the other end are expecting, and it means they will know what bit they missed, based on the order. Radio procedure gets messages through when the conditions for communication are marginal. Learning the proper phonetics for use on the radio would help as well.

For a good example of the difference it makes, the "mayday" call of the ferry Estonia when it was sinking: https://www.youtube.com/watch?v=TT8D7zSbkdE

(This has the additional problem of several different languages going on...)
 
Chances are you will never have to make a Mayday call. Why not printout one of the many Mayday templates available on t'internet (not the RYA one, it's out of date), fill in your details, laminate it and stick it up beside your radio. Then you do not need to remember anything and, perhaps more importantly, someone who hasn't had the benefit of the SRC course (or this forum) can also make a Mayday call when you fall overboard.
 
Erbas said:
Will do just fine for what? It's just three abritrary, ambiguous and ultimately meaningless numbers
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No more than the full MMSI is just ten abritrary, ambiguous and ultimately meaningless numbers. In aviation RT procedure, the full callsign (Golf-alpho-bravo-charlie-delta) is only used in making initial contact; thereafter just the last two letters (charlie-delta) are used. How likely is it, do you think, that the coastguard would be dealing with so many DSC distress calls at one time that they would get confused if only three digits were given? Bear in mind that they also have the vessel name and should have the callsign, both of which are linked to the MMSI on the ITU database.
 
I've been following this thread with interest because in a few days' time I shall be attending the SRC course myself. I have the RYA booklet G22 and the Reeds VHF DSC Handbook, and there are minor differences between them However, referring to the OP's initial question: The RYA G22 on Page 25 reads:

Mayday, Mayday, Mayday
This is Yacht Calamity, Calamity, Calamity, MMSI 234001234
Mayday Yacht Calamity.
My position is 50 (degrees) 46' (mins) North 001 (degrees) 17' (mins) West
Swamped in rough sea and sinking
(Etc. Above brackets as my PC won't produce symbol for degrees)

The Reeds handbook an page 87 reads:

Mayday, Mayday, Mayday
This is Hot Stuff, Hot Stuff, Hot Stuff
MPTY9, 232001478
Mayday Hot Stuff, 232001478 MPTY9,
My position is .......
(Etc)

Whereas the 'official' RYA message only mentions the MMSI once, and not the Call sign of the vessel at all, the Reeds Handbook mentions both the MMSI and the call sign twice.

Obviously the RYA message is more concise. On my course I will do as the Instructor dictates. I remember when doing my education exams in the Army, we were always told 'if you want to pass, do it the way you are taught, not the way you think it should be done'.
 
JumbleDuck said:
No more than the full MMSI is just ten abritrary, ambiguous and ultimately meaningless numbers. In aviation RT procedure, the full callsign (Golf-alpho-bravo-charlie-delta) is only used in making initial contact; thereafter just the last two letters (charlie-delta) are used. How likely is it, do you think, that the coastguard would be dealing with so many DSC distress calls at one time that they would get confused if only three digits were given? Bear in mind that they also have the vessel name and should have the callsign, both of which are linked to the MMSI on the ITU database.
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And once again you make the mistake of assuming that the person dealing with your mayday will have access to the ITU database, or any database for that matter. And that there is no possibilty whatsoever of two vessels with the same last three digits operating DSC communications within the receiving range of any station receiving the communications. That is a very large assumption

The full MMSI number is neither arbitrary nor meaningless (any more than a telephone number is aribtrary or meaningless) and to suggest that it is clearly indicates a lack of knowledge of DSC VHF comms. It;s not just a random sequence of numbers!

In any case, you only have to quote the MMSI at all twice, and then only if the initial alert was raised by DSC (otherwise you don't need to quote the MMSI at all)

Rather like your aviation example, the MMSI is quoted once in the Mayday preamble and then once in the initial Mayday message.

Thereafter it it not required at all and (normally) further communications will be addressed to / from "Mayday name_of_vessel"
 
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