AIS

As has been posted elsewhere by the great authority that is John Morris ...
Applying good seamanship may require interpretation of the IRRPCS.

Attached is an AIS chart of the central english channel now. The pink box shows the non TSS area that I would argue is still effectively controlled as narrow channels to allow this volume of vessels to flow with no issue. Given that to the left is the Casquets TSS and to the right is the Dover TSS, is it realistic to expect the shipping on the inside to have to take avoiding action of those crossing, when to do so means turning towards other vessels that are closeby causing a greater risk of collision?
I would therefore say rule 9 applies to us yotties in these areas.
 
This thread sickens me and only serves to confirm my growing suspicion that ScuttleButt is little more than an online asylum for psychologically damaged British yachtsmen.

When someone quotes an example where AIS allowed him to avoid a close 0.1nm encounter with a ship, he is accused of overzealous use of the technology. The technique is derided as something that would make crossing a TSS impossible.

When others claim that AIS allowed them to interpret a complex crossing situations and hold a course so as not to spook commercial shipping with random maneuvers. This is criticized as stupidity in trusting unreliable technology instead if trusty old eyeball navigation.

I have personally crossed the Casquets shipping lane this year where on screen the traffic looked impossibly congested to let a yacht through. However after clicking on all 7 threats lined up against me I realized I was going to slide through the whole pack without needing to tweak the helm.

No doubt the rabid anti AIS faction are frothing over their radar vacuum tubes trying to work up a criticism of what I did.

What I find most incredible of all is that this self righteous belief comes from a contingent of yachtsmen who have never used AIS in anger. They should stop for a moment and ponder why so many merchant marine mariners navigating through the English Channel quote AIS figures at other ships on the VHF.
 
To me one of the problems here is that situations are answered that are not the ones used in original examples. As I said, the scenario I faced was a vessel hidden be another in good viz, which I find increasingly common. I never mentioned any distance, and certainly not 7 miles. However, now you've arbitarily thrown in 7 miles, how about the the two vessels appraoching at combined 21 knots, you with the kite up. Suddenly 7 miles (20minutes) starts to look like an important time to decide what to do, or at least PLAN.
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The 7mls scenario was one put in by Huzar30 to whom I was originally replying but this forum format doesn't allow logical flow of replies sadly.

Agree that predicability is the name of the game, so trying to make as few course alterations as possible must be helpful? If you take the one at a time approach (and the golf analogy - a straight walk from T to pin never happens if your shots are like mine
) then each time you pass one ship you change course again. If I was 1 of those 14 ships you counted and I could see a blip "bouncing from one avoiding strategy to another I'd be more confused than see a vessel maintaining constant course (admitedly potentially varying speed, under sail, but something you could average out)
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Actually when we were crossing off Ushant our course was one that converged onto the lanes, such that we saw the ships in the lanes from maybe 8mls but took over 2 hours to reach them even at 7kts (figs from memory). Even though we counted that many ships we made NO alterations of course at all because as each one came closer it became obvious we were clearing it easily. We were under sail and making between 7 and 8 kts.

As I've said, AIS is no substitute for standing in the cockpit and watching. But it does provide valuable information. Why else is it becoming a tool for all larger vessels? The quality will improve as usage increases. As for not updating for 5 mins, if a vessel is travelling at more than 5 knts you easily see the lat long of their transmissions change.
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AIS is not used as a collision avoidance tool by ships though. This is very much the downfall of the newer AIS sets on small boats that transmit as well as receive and people expect their boat to be displayed on the big ship bridge when it probably isn't. Many ships do not even have received AIS data overlayed on their radar or plotters. Just because small boats have this facility shouldn't lead to an assumption that the big boys do although I think that will be the case in future. However if everyone by then has transmitting AIS chaos will rule, filters will be applied and we are back to square one.

I'm not at all against AIS by the way but I think some people are in danger of giving more credence to it's predictions than to the evidence of their own eyes or are using it to make course change decisions at unnecesarily long ranges, it was the 7ml one that got me started on this!
 
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Robin said:
AIS is not used as a collision avoidance tool by ships though.
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Yes it is but you just don't know that because you have not switched your VHF on for years because of all the DSC alerts.

As to the value of class B transmissions, that is a completely different debate. Anyhow someone with industry knowledge posted here saying the spec requires that a class B suppression visual filter has to auto release.
 
jonjo said:
This thread sickens me and only serves to confirm my growing suspicion that ScuttleButt is little more than an online asylum for psychologically damaged British yachtsmen.

When someone quotes an example where AIS allowed him to avoid a close 0.1nm encounter with a ship, he is accused of overzealous use of the technology. The technique is derided as something that would make crossing a TSS impossible.

When others claim that AIS allowed them to interpret a complex crossing situations and hold a course so as not to spook commercial shipping with random maneuvers. This is criticized as stupidity in trusting unreliable technology instead if trusty old eyeball navigation.

I have personally crossed the Casquets shipping lane this year where on screen the traffic looked impossibly congested to let a yacht through. However after clicking on all 7 threats lined up against me I realized I was going to slide through the whole pack without needing to tweak the helm.

No doubt the rabid anti AIS faction are frothing over their radar vacuum tubes trying to work up a criticism of what I did.

What I find most incredible of all is that this self righteous belief comes from a contingent of yachtsmen who have never used AIS in anger. They should stop for a moment and ponder why so many merchant marine mariners navigating through the English Channel quote AIS figures at other ships on the VHF.
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Oh FFS I'm outa here.
 
jonjo said:
Excellent resource.

The live maps demonstrate so clearly why West Coast Scottish readers cannot comprehend the issues being debated. They would wet their sporrans navigating a yacht between Poole and Guernsey.

They don't have a clue and never will.

p.s. most of the radar contacts on the Scottish west coast are shore stations.
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Actually they look to be giving it a go, presently there is 10m sailing yacht 5 miles south of St Cathrine's, called "Celtic Flame" transmitting a class B signal, not making much speed at the moment.
 
Having found the boat 7nm away with a CPA of 0.nm, then since I was motoring, I blipped the autohelm 5 degrees, did nothing else for the next forty minutes, and he passed clear ahead.

So where's the problem?
 
huzar30 said:
Having found the boat 7nm away with a CPA of 0.nm, then since I was motoring, I blipped the autohelm 5 degrees, did nothing else for the next forty minutes, and he passed clear ahead.

So where's the problem?
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None what so ever, and you had a peaceful 40 minutes to enjoy another drink without jumping up to take bearings every 5 minutes...
Just like GPS Chart plotters gave us an easier way of getting to those out of the way places. Sure you shouldn't rely on them to the exclusion of all else, but they sure do help.

JonJo, Huzar30 here's to taking a progressive view of the future!
 
huzar30 said:
So where's the problem?
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The problem is entrenched views and perceptions change slowly.

Six or so years ago I was the first person to express my excitement about the potential for AIS on this forum. I was able to read the technical specs, infer the minuscule computing power it would take to run the O level trigonometry calcs on a tiny plotter device and so deliver extremely accurate collision predictions to the small boat navigator.

At the time I was a lone voice shouted down by all the resident experts who could still picture the invoice for the not too distant vacuum tube radar installation on their boat and the evening courses spent slaving over getting the hang of radar plotting sheets.

The rapid and wide uptake of AIS has surprised everyone so now the anti AIS brigade resort to condemning the technology based of edge cases e.g. "I saw a ship doing 20knots up the Channel at "anchor" therefore the technology is obviously rubbish".

More gaulling is the arrogant assumption that because you publicly admit to using AIS the the anti brigade immediately conclude that you must be a yachting incompetent who crosses the channel sat at the chart table trying to find the space invaders game on your AIS display.
 
You arrogant prat

jonjo said:
Excellent resource.

The live maps demonstrate so clearly why West Coast Scottish readers cannot comprehend the issues being debated. They would wet their sporrans navigating a yacht between Poole and Guernsey.

They don't have a clue and never will.

p.s. most of the AIS contacts on the Scottish west coast are shore stations.
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You arrogant prat :mad:

I am interested in AIS not for dodging the Clansman in the Sound of Mull but for our next trip across the Bay and down the Portuguese coast in thick fog. I fully understand its value and its limitations, and indeed have been a staunch supporter of it and defender of its use in previous threads on here. I merely commented that you were misusing it if you were making course alterations at ten miles based on AIS data alone. As far as I can see I am not alone in that opinion.

Your assumption that because we are based up here we have not sailed elsewhere is patronising and typical of the conceited nonsense we have come to expect from you.

You take care now - I wouldn't want to hear that you have been run down in an AIS-assisted collision.

- W
 
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webcraft said:
I merely commented that you were misusing it if you were making course alterations at ten miles based on AIS data alone. As far as I can see I am not alone in that opinion.
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You are not alone indeed, but firmly entrenched among a diminishing group of yachtsmen who are confident enough to condemn example use of the technology despite no regular experience of its use.
 
jonjo said:
More gaulling is the arrogant assumption that because you publicly admit to using AIS the the anti brigade immediately conclude that you must be a yachting incompetent who crosses the channel sat at the chart table trying to find the space invaders game on your AIS display.
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Exactly what do the French have to do with this - other than, almost certainly, referring to it as SIA? It must be nice to sail in seas where everyone proceeds in nice straight lines - what's the scenery like?
 
these ships tend to hunt in packs, you know, so AIS or radar is great so that the packs can be spotted from a great distance and thus avoided.
 
As an early poster to this thread then left it as I had other things to do (yes - apparently there is life outside this forum) ....
I am amazed at some of the responses on here ... AIS data is an extreemly useful additional tool and whilst most of the time you can stand on until much closer it can occaisionally be used to alter course whilst still quite a way from the target vessel - especially if there is a larger pack of vessels which you have on AIS - it is perfectly possible to alter course by a few degrees to ensure you pass round the back of all of them in one go rather than have to dodge each one individually - but each case is different.
The apparent agressive tone by Robin did suprise me - but the point he's quite right in making is that you shouldn't rely purely on AIS to do the collision avoidance - that's what eyes were made for!
 
fireball said:
As an early poster to this thread then left it as I had other things to do (yes - apparently there is life outside this forum) ....
I am amazed at some of the responses on here ... AIS data is an extreemly useful additional tool and whilst most of the time you can stand on until much closer it can occaisionally be used to alter course whilst still quite a way from the target vessel - especially if there is a larger pack of vessels which you have on AIS - it is perfectly possible to alter course by a few degrees to ensure you pass round the back of all of them in one go rather than have to dodge each one individually - but each case is different.
The apparent agressive tone by Robin did suprise me - but the point he's quite right in making is that you shouldn't rely purely on AIS to do the collision avoidance - that's what eyes were made for!
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I wasn't being aggresive at least not intentionally but merely trying to point out some of the inaccurate comments being made by some posters. If that is the impression given however I guess I'll stop posting, that way the sensitive will not be offended if I disagree.

For the record as a last comment on this post:-

The English Channel is NOT a narrow channel to which special rules apply.

Apart from in the TSSs themselves normal IRPCS rules apply, the entire Channel is not treated as a TSS.

AIS is a very useful piece of kit to have and I have never disagreed with that, especially if you already have radar. I just raise eyebrows to hear that (some) people are using it to make course alterations for ships that are still out of sight over the horizon or only just appearing. What next? Look up AIS live on the internet before departure and plot a course avoiding ships from home? :) (I inserted the smiley in case some people think I'm being nasty...) I also raise eyebrows when I hear some people think it is a valid total substitute for radar.:)(I inserted the smiley again in case some people think I'm being nasty...)

Don't just sit below looking at a laptop or plotter screen to see how close a ship is going to pass, take a look outside sometimes!:)(usual caveats)

Don't panic and take huge detours avoiding ships seen on a screen, the reality is that there ARE plenty of gaps and mostly you will go through completely unimpeded as long as you keep a good lookout, follow IRPCS and use simple commonsense.

So there you go guys, over and out.:p
 
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