Distress Procedure

AndyB007 · 28 July 2007, 19:44

Question for qualified instructors only please; I've recently been told that the DSC Distress procedure no longer requires you to wait for a Distress acknowledgement being received, or after about 15 seconds, before transmitting a MAYDAY message by voice. This has come (via a third party) from a RYA Training School.

Is this correct?

Thanks

Andy

Solent Ranger · 28 July 2007, 22:56

Andy - it is a requirement to send a voice follow up after having sent a DSC distress alert. It is not a requirement to "wait" for an acknowledgment before sending the call by voice.

The 15 second "waiting" period has nothing to do with waiting for the DSC alert to be acknowledged and only certain stations can do this. Class D VHF sets, fitted to leisure vessels cannot acknowledge DSC distress alerts so if you wait you may miss the boat!

blimp · 29 July 2007, 09:31

I agree with Solent Ranger - I'm not a qualified instructor, but just completed my VHF-SRC course. The DSC message can only be acknowledged by an authority, so you should ALWAYS follow-up with a voice call (assuming of course that you haven't just sent the DSC and had to chuck yourself over the side!!). If nothing else, your original DSC transmission will automatically get all local radios on to channel 16 (in case some hadn't been holding a listening watch)

AndyB007 · 29 July 2007, 10:23

Quote:

Originally Posted by Solent Ranger

The 15 second "waiting" period has nothing to do with waiting for the DSC alert to be acknowledged

What purpose does it serve then??

Solent Ranger · 29 July 2007, 16:24

It gives those listening time to get ready to expect the voice call. Under the "letter if the law" you should right down all Mayday/Distress calls and establish the position.

It is not a time set in stone. Could equally be 10 seconds or 20 seconds - your choice. It is however sensible to give a short pause so that people responding can turn the alarm on their radios off, so they can hear the voice call.

It's that good old nautical term again - use common sense! But be assured, it has nothing to do with waiting for the DSC alert to be acknowledged before putting out the voice call - I can't emphasis that enough! Yours and other people's lives could be put at risk if you follow that rule.

Not every small vessel is equipped with a DSC radio and it could be the vessel nearest to you. They won't know your sat there waiting for an acknowledgment to your distress alert because they won't have heard it.

The card provided on your boat is correct!

Doug Stormforce · 30 July 2007, 12:11

Quote:

Originally Posted by AndyB007

I've recently been told that the DSC Distress procedure no longer requires you to wait for a Distress acknowledgement being received, or after about 15 seconds, before transmitting a MAYDAY message by voice.

Andy

Andy

There has been no change here, you were never required to wait for an acknowledgement.

That said in coastal waters it would be highly unlileky that you did not receive an acknowledgement from the Coast Guard but as S/ranger has said the waiting time is to give people a chance to get to their sets, switch of the alarm, grab a pen, tell the kids to shut up etc.

If your set does not receive an acnkowledgement digiatlly it will contiunue to send out a DSC alert roughly every 4 mins. If a larger commercail (GMDSS compliant) vesssel hears your alert they should acknowledge the second time it is sent. This situation could arise for exampl in the western approaches to the E Channel wher you are out of range of CG but in range of commerciual traffic.

Roughly speaking those who can acknowledge are obver 24m, 12 passenegrs or 300tonnes

AndyB007 · 30 July 2007, 17:44

Thanks for your input Gents. The procedure to wait no more than 15 seconds before transmitting a voice message appears to be consistent as per the training. If you receive an acknowledgement in that time - great!

However, it would take a pretty cool cookey to wait this long - when the s**t hits the fan every second will seem like an hour!

Andy

peterb · 30 July 2007, 18:01

The fundamental weak link in the chain here is the poor old systems that the Coastguards have to work with! Its not their fault, but the systems are not interfaced in a sensible manner

When you hit the distress button - HMCG Ops Room lights up. So far so good - and they do know your lat/long (assuming an interfaced and a correctly working GPS).

Where the system falls down is - they only know your MMSI number at this point. So they could only reply "Mayday Station with MMSI 12345678, this is XYZ coastguard...."

In reality they have to take the MMSI number, copy and paste it into the ITU database and retrieve your Ship Name. (Or alternatively they might look on CG66).

Then and only then can they say "Mayday AndyB, this is YXZ coastguard".

alystra · 31 July 2007, 08:43

Quote:

Originally Posted by peterb

The fundamental weak link in the chain here is the poor old systems that the Coastguards have to work with! Its not their fault, but the systems are not interfaced in a sensible manner

When you hit the distress button - HMCG Ops Room lights up. So far so good - and they do know your lat/long (assuming an interfaced and a correctly working GPS).

Where the system falls down is - they only know your MMSI number at this point. So they could only reply "Mayday Station with MMSI 12345678, this is XYZ coastguard...."

In reality they have to take the MMSI number, copy and paste it into the ITU database and retrieve your Ship Name. (Or alternatively they might look on CG66).

Then and only then can they say "Mayday AndyB, this is YXZ coastguard".

Nothing much has changed there then. 'Son of ADAS' still doesn't give the right answers, it seems. Only Bill Gates's stuff is more obtuse.

Doug Stormforce · 31 July 2007, 10:14

Quote:

Originally Posted by peterb

The fundamental weak link in the chain here is the poor old systems that the Coastguards have to work with! Its not their fault, but the systems are not interfaced in a sensible manner

When you hit the distress button - HMCG Ops Room lights up. So far so good - and they do know your lat/long (assuming an interfaced and a correctly working GPS).

Where the system falls down is - they only know your MMSI number at this point. So they could only reply "Mayday Station with MMSI 12345678, this is XYZ coastguard...."

In reality they have to take the MMSI number, copy and paste it into the ITU database and retrieve your Ship Name. (Or alternatively they might look on CG66).

Then and only then can they say "Mayday AndyB, this is YXZ coastguard".

Not entirely accurate, If you send a DSC alert then your acknowledgment comes digitally so the poor old coast guard has only to press a button and then wait for your voice call, which will then provide him with more info. The manner the systems are interfaced seems quite sensible if you look at the over all system.

You send DSC alert you get DSC acknowledgemnet.

You send distress call by voice you get a voice acknowledgment.

The alternative is we rely on members of the public seeing distress flares and dailling 999

genoa · 31 July 2007, 12:38

Quote:

Originally Posted by Doug Stormforce

You send DSC alert you get DSC acknowledgemnet.

You send distress call by voice you get a voice acknowledgment.

The alternative is we rely on members of the public seeing distress flares and dailling 999

Seems very sensible. If I send and SMS on my phone that requires a yes or no answer, I'd rather not get a phone call back - more things to think about!

Two good reasons why in this situation the procedure is good:
1. if I send a DSC, chances are I'll have a fire extinguisher in the other hand, and it'd be good if I just see an 'acknowledged' message on the VHF, and the alarm beep.
2. If the CG were to use the audio part on the radio the'd also certainly cut over me if I am trying to radio out my mayday as well for non DSC users to respond to, so I'd rather they didn't do a voice response until I've had a chance to do my bit first .....

AndyB007 · 31 July 2007, 14:40

Quote:

Originally Posted by Doug Stormforce

The alternative is we rely on members of the public seeing distress flares and dailling 999

Love the Joe & Petunia advert "... lovely day i'nt it?"

Andy

peterb · 31 July 2007, 15:54

Quote:

Originally Posted by Doug Stormforce

The manner the systems are interfaced seems quite sensible if you look at the over all system.

Sorry, I disagree Doug. What should happen with any DSC call - be it urgent, safety, distress or just a general call - is that the Ops Room should receive the call and automatically their systems should display all the relevant info about the boat. Not just the MMSI, but all salient info.

This doesnt happen yet as there is no interface between the DSC and voice.

So if you call Solent CG on their DSC number of 002320011 in readiness for giving them traffic, they will then have to turn to a separate and non-interfaced system like ITU or CG66 to retrieve even the basic information like your boat name.

The Ops Room staff know that this is an antiquated system, but until such time as there is a radical rethink, thats how it will remain.

Doug Stormforce · 01 August 2007, 10:59

Quote:

Originally Posted by peterb

there is no interface between the DSC and voice.

Not sure what interface you are asking for, the DSC is a calling system and the voice is a communications system. If you are sinking and you put out a ditess alert you get their attantion and then know where you are and maybe even the problem. The interface to voice is human, ie you follow up with voice call.

Quote:

Originally Posted by peterb

So if you call Solent CG on their DSC number of 002320011 in readiness for giving them traffic, they will then have to turn to a separate and non-interfaced system like ITU or CG66 to retrieve even the basic information like your boat name.

I take your point and agree this would be an improvment