YM fog-collision article

[Ric]

In the March 2004 edition of YM there is an article about a collision in the channel between a Moody 47 and a cargo ship. There is something a bit odd about this article, and perhaps somebody could elaborate.

First, it seems the Moody was motoring (unlikely to be doing 7.5 knots in F1-2) though the article is rather coy about mentioning this. The Moody was travelling north, the cargo ship west - therefore (in good viz) the cargo ship would be the "stand on" vessel. But the Moody skipper (allegedly sailing for 41 years) thought HE was the stand on vessel. To add to the confusion, elsewhere in the article it mentions that inspectors found traces of the Moody paint on the "starboard bow" of the cargo ship, and that the cargo vessel loomed out of the fog from the port side. Also, if you look at the picture taken by the skipper of his dismasted and bowless boat shortly after the collision the visibility looks pretty good.

Weird article!



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[HaraldS]

do you mean the article in YM or YW? I don't have a YM as I buy it on occasion, butthe same story was in Yachting World amonth ago, and I agree it is quite strange and raises more questions than it answers. The latest YW has a follow up on radar and ARPA usage, which seems to make even less sense.

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[charles_reed]

Chaos theory? nm

nm

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[Benbow]

You can see an account from the MAIB <A target="_blank" HREF=http://tinyurl.com/2gqlb>here</A>

Looks to me like both parties made some extraordinary errors to arrange this collision despite each having the other on radar. The Moody was motoring and would have passed clear ahead, but didn't know this because they didn't know how to use their radar. They panicked at the last minute and stopped right in the ship's path. Ship was doing 25kn in very poor viz !

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[slavkod]

I have read an artichle. It is strange for me that they never used VHF. Last year when we have been passing Adriatic sea from Dubrovnik to Brindisi we used ARPA capability on our radar but in case nor been shure we always made a call over VHF. All big ships were responding and confirming that they have us on their radar. Sometimes we do tests of our radar, even during a clear day. Again all ships are very cooperative.

Slavko

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[Benbow]

We are repeatedly being advised NOT to use VHF for collision avoidance. The potential for added confusion and distraction is immense. In fog in a busy shipping channel with an unidentified radar return it would be very difficult to be sure who you were talking to. Far better to stick to the rules (and plot the radar contacts).

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[HaraldS]

When you say we have been advised not to use VHF, who do you mean with we and who's advising? Use of VHF seems quite common practise and I find a lot of comercial shipping is using VHF to clarify certain sitiuations. I agree though that it might be confusing and certainly not error free. But as has been demonstrated, ships can meet radar or radio assited...
Anyway, with AIS and the MMSI number of the target in question on your screen, I wouldn't hesitate to place a selective call in an uncertain situation.

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[Benbow]

MAIB have promulgated notices about this and MCA professional courses drum in the message that you must apply the rules and not risk the confusion and distraction of using VHF.

Imagine yourself on the bridge of a ship in fog worrying about an intermittent radar return that may be a small boat. Suddenly you hear an 'all ships' call on the radio from a yacht who says he has you on radar and will pass behind. If he was a really good skipper with a good radar he could give a pretty good estimate of the position, course and speed of the ship he was calling. But you would still have to take time to check that he may be calling you, you would then have to check his given position, see if that matches the radar return and decide what to do. What if his position does not correspond with any radar return ? What if he wasn’t a really good skipper and there were errors in the information he passed ? Add to that possible language problems and you have serious potential for confusion.

I agree that the risks would be reduced if you had a positive id on a vessel and were confident that they could identify you unambiguously. But when dealing with fast ships in busy open waters, I have never experienced such a situation.

Certainly the situation is different in a narrow channel and under the control of a port radio. Operating big yachts under such circumstances I would be in communication with the port radio who have me and other vessels on radar, then it is common to call a named known vessel and agree a passing procedure. Even then the conversation is typically along the lines of 'yes you may overtake me on my port side, I will stay up on the greens', in other words pretty conservative manoeuvres being discussed and the VHF being used to confirm them. Because the port radio tells me who is about and where they are going and because everyone follows the rules there should be no need to do more than this. For instance, if I needed to cross the channel to come alongside, I would let the port radio know when I was about to turn, but I would NOT attempt to negotiate a crossing procedure with other vessels. It would be my responsibility to do it safely according to the rules.


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Just googled for this, found 100's of hits. eg <A target="_blank" HREF=http://www.mardep.gov.hk/en/notices/mdn99020.html> this </A> <P ID="edit"><FONT SIZE=-1>Edited by Benbow on 21/03/2004 21:08 (server time).</FONT></P>

 

[slavkod]

When I have posted my reply, idea was just to give my experience. With radar system performance one have, it is easy to check the big boat direction and speed. If you call them with this data and give them position, again from radar, this will not build any confusion. In the case of Moody this could help. That is all. Regulations?? You are right. Do we have to play by all the time?? I would call.

Slavko

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[Benbow]

Well in the case of the Moody it certainly would not have helped because the Moody skipper did not know how to use his radar ! In fact ironically, if he had not had radar there would have been no collision.

There are plenty of accident enquiries that have concluded that situations were made worse (or entirely caused) by attempts to use VHF.

I agree that improving technology may change the situation in the future. But at present in the busy foggy English channel with many fast moving ships, few yachts have radar platforms stable enough to unambiguously identify a ship by position course and speed. And even where they can, they may still make the situation worse.

But I have to confess that I once did call-up a fishing boat, whose name I could read through binoculars to check how close astern I could safely pass – I had a spinnaker up and really did not want to gybe !


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[kesey]

Benbow, I think you are being very unfair dropping all the blame of the Moody skipper.

The idiot driving the container ship thought 2 cables was a wide enough CPA. That alone was a major error, but he also apparently forgot that his bridge was situated well aft of his bow, and that 2 cables per the radar was not 2 cables clearance between the vessels.

5% error in calculating CPA on the part of either radar system would be enough to put the vessels in jeopardy. The closer the container ship got to the Moody, the more overwhelmed the Moody's radar would be with radar contacts.

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[Benbow]

I totally agree that both were at fault, this discussion has drifted radically, but if you look at my 1st post on the subject you will see that I said that I thought both made errors. Sorry if subsequent ramblings have lost sight of that.

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[Sinbad1]

I understood that the Moody skipper did NOT think he was the stand-on vessel. He had in fact reduced power and was in neutral when hit, certainly not the act of a stand-on vessel. Tha MAIB had apparently incorrectly reported that the moody skipper had 'thought' that he was the stand-on vessel.

The loss, which very easily could have been tragic, was caused by both vessels relying on their radars and the new sophistication of marpa. Without marpa you would use your EBL to determine if there was a collision possibility and would take avoiding action much earlier. Where you have an electronic instrument telling you its ok to proceed, modern man proceeds.....and greatly decreases the safety margins.e

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[HaraldS]

I really agree with you that the master of the container ship was risking way too much being satisfied with such a narrow CPA. Also the relatively high speed difference between the cargo ship and the yacht are a problem, as the big ship's ARPA has little time to establish a reliable vector of such a slow moving target.

That's where I think a resonable speed would be one that allows to establish proper vectors and then still have some time to establish good decisions based on these.

The relative position of the radar antenna and the size of the vessel are however taken care of in the ARPA setup and I'm quite sure it calculates the CPA with those dimension in 'mind'.

It is also quite likely that the radar lost contact to the yacht when she was in close proximity, as it would be covered by the containers. So the reported distance may well have been based on the last contact.

Like most here I think both sides made some errors. Those of the Moody skipper we can hopefully avoid and may be attributed to lacking experience in radar navigation, but the master of the cargo ship was knowingly taking a high risk,and will likely continue to do so.

So, we on the small boats should simply feel hunted and try to escape;-)




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