AIS Class A & B v Radar

jfm said:
I agree what you say generally, but just to be clear, in discussing the legality of having a radar turned off I was talking only about the situations where I know it makes zero difference to safety, as was MapisM. For example, when you come out of the marina on a sunny calm day and go 5 miles along the coast to anchor in a bay to go swimming. I was debating merely the point of law, and I'm certainly not against using a radar in other situations when it is useful, or practising with it in perfect weather, and so on. I wouldn't spec a boat without one (and I'm contemplating fitting a second one, as part of my winter updates!)
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Surely the point is that the chances of getting prosecuted for not having the radar turned on while you are not having a collision are vanishingly small - nobody is checking. If you are involved in a collision and it can be shown that the radar was turned off, it is a lot more difficult to prove that having it on would not have reduced the chances of the collision.
 
I can't think of one single situation, while coastal cruising in perfect visibility, where keeping your eyes on the radar screen could avoid a collision that you couldn't avoid by keeping your full attention directly around you.
I'm not saying that a judge couldn't use the "radar off" argument, if indeed there is such regulation, because I'm well aware that law and common sense don't necessarily match.
But that would be mental, imho.
 
MapisM said:
I can't think of one single situation, while coastal cruising in perfect visibility, where keeping your eyes on the radar screen could avoid a collision that you couldn't avoid by keeping your full attention directly around you.
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Depends if you're driving from below or not. On some boats the visibility from the lower helm is often not ergonomically correct and often impeded by windscreen mullions or other stuff. Then there is always the chance that a small boat or a pot marker is partially hidden in wave troughs if there is some sea running and the radar may pick up that kind of target earlier than you see it by eye. Don't forget that the radar scanner is usually considerably higher than the lower helm. The other reason for having the radar on in perfect viz would be to put the EBL on any targets you can see to guage whether you are on a collision course with it.

Yes sure if you were driving from the flybridge there wouldn't be much point in having the radar screen on up there
 
Hi Guys, I have an hour or so spare before attending an exhibition, and I'm in a small town called Polakwane in the Limpopo region. Sounds just like the Jungle Book, but there aren't any clever crocodiles around!

OK, just to make sure of my references, when I was commissioned to write the article on radar for MBM, I was asked specifically to attend the Robert Avis radar course and report on it. The reason was that great interest was being shown in the use of radar following the MAIB's report on the accident between the P&O Nedlloyd Vespucci and Yacht Wahkuna.

Robert's course was chosen given his qualifications and the fact that he was pioneering an additional element to the RYA radar course on whether a radar should be sea stabilised or ground stabilised when using MARPA for collision avoidance - something picked up in the MAIB report.

The late Captain Robert Avis, OBE RD DL FRIN, held a Master’s Ticket for yachts up to 3,000 tons, had 370,000 sea miles under his keel of which 35,000 were in command of 11 warships and 62,000 skippering large yachts. In 2004 Robert was elected a Fellow of the Royal Institute of Navigation for teaching radar to both professional and amateur yachtsmen.

The course was brilliant, but it led me to meet with the Coastguard Agency (MCA), the enforcement body for the COLREGs in the UK, to ratify a specific comment Robert was emphatic about, that radar always be on when you are underway. The words I recorded from the MCA’s Navigation Manager were,

“Of course, in the context of Rule 6, ‘operational’ means working and turned on and working, (otherwise one that was not turned on would be a major characteristic under 6(b)(i)).

“If it is turned off, it might as well not exist and you cannot include the radar on board within consideration of safe speed in accordance with Rule 6. Additionally if you have radar in circumstances where it could be of value such as in restricted visibility and then decide not to turn it on or use it, you could be in violation of Rule 2 and/or Rule 5.”

"In other words, if it’s fitted to the boat, it must always be on when underway.

"Furthermore, case law shows that if your craft is fitted with radar you must use it and by implication know how to set it up and use it to its full potential for the conditions you are experiencing."

More than this I do not have, that's relevant to this comment. Looking back, I'd have liked to known 'what case law?'

On Play 'eau, we always have the radar on not the least so we can see what's coming up behind. remember, that from the pilothouse of the Fleming, you have no visibility aft so radar becomes invaluable, not the least that I cruise at 8 knots.

So that's the limit of my knowledge. maybe I should ask the MCA for the case law as a follow up.

Another interesting point discussed with Robert was whether radar should be set North Up or Course up. He gave some examples of potential radar pictures in both situations to show the difference. As a result, I travel with radar North Up. Even if I didn't understand the difference, it makes more sense given I have the radar screen next to the chart plotter screen.

Must leave for the conference.
 
Interesting reading, thanks for taking the time to dig into your files. I'm still a bit puzzled, though:
Piers said:
“If it is turned off, it might as well not exist and you cannot include the radar on board within consideration of safe speed in accordance with Rule 6. Additionally if you have radar in circumstances where it could be of value such as in restricted visibility and then decide not to turn it on or use it, you could be in violation of Rule 2 and/or Rule 5.”

"In other words, if it’s fitted to the boat, it must always be on when underway.
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Firstly, in my understanding of the above quotes, I'm not sure that the "must always be on" bit descends univocally from the previous explanations.
What if I'm underway, but pootling at 5 knots in perfect visibility?

Secondly, in my boat I only have the radar screen in the main p/h, and it's not repeated in the f/b. Now, most of the times (if not all) I decide to go out, it's because the weather/visibility is great, and I'm helming from upstair. That obviously gives me the best possible visibility, but makes it irrelevant whether the radar is turned on or not.
According to the above statement, I suppose I should not only keep the radar on at all time, but also helm from below - hence having a somewhat more restricted visibility!
If that's what I should do to be 100% complaint with the rules, I'm afraid I'll have to accept to be called an outlaw, because I don't think I'll change my habits anytime soon...
...I'll more likely leave that to whenever I won't be able to climb on the f/b stair anymore! :D
 
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My view is that the key phrase is "proper use" of radar in 7(a). Additionally, in all of the other instances where radar is mentioned in Colregs it is as a factor to be taken into account. By not using it you run the risk of it being established that it would have made a difference. Hence, if you are confident that you can demonstrate that it wouldn't have added anything then it is quite difficult to see how any tribunal would be able to criticise the non-use of radar unless your confidence turns out to be misplaced.

You could say that this means that Colregs is an early adopter of an "outcomes focused" approach (aka, "come down on you like a ton of bricks if you happen to guess wrong") rather than an old fashioned prescriptive approach ("Do this. Don't do that")
 
Piers said:
The late Captain Robert Avis, OBE RD DL FRIN, held a Master’s Ticket for yachts up to 3,000 tons, had 370,000 sea miles under his keel of which 35,000 were in command of 11 warships and 62,000 skippering large yachts. In 2004 Robert was elected a Fellow of the Royal Institute of Navigation for teaching radar to both professional and amateur yachtsmen.
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Thanks, Piers. Robert trained me on my own boat for my Yachtmaster practical exam and it was 3 of the best and most informative days I have ever had on the water. As far as I'm concerned what he didn't know about navigation wasn't worth knowing but at the same time, he was a very practical mariner, a very patient teacher and excellent company. So sad that he died at such a young age
 
Therein lies an advantage to AIS in as much as with the right kit you can be transmitting as well as receiving, so the problem of not showing up on the radar of the Pride of Bilbao or the catamaran the zips between the CI and St. Malo is addressed. If you were of a cynical bent, you might think that showing up as a clear blip (which can be replayed at an MAIB enquiry) is a good incentive for whoever is on watch not to drive into you - if only to avoid the subsequent embuggerance. I fitted the send/receive box to my boat as the cost, over and above the simple receive box seemed, in the grand scheme of things, to be the proverbial halfpennyworth of tar. But I do agree, it isn't Radar.
 
Dick Atcherley said:
Therein lies an advantage to AIS in as much as with the right kit you can be transmitting as well as receiving, so the problem of not showing up on the radar of the Pride of Bilbao or the catamaran the zips between the CI and St. Malo is addressed. If you were of a cynical bent, you might think that showing up as a clear blip (which can be replayed at an MAIB enquiry) is a good incentive for whoever is on watch not to drive into you - if only to avoid the subsequent embuggerance. I fitted the send/receive box to my boat as the cost, over and above the simple receive box seemed, in the grand scheme of things, to be the proverbial halfpennyworth of tar. But I do agree, it isn't Radar.
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Isn't it a pretty widely held understanding that many commercial vessels can, and do, filter out the AIS broadcast from leisure vessels, so maybe it's not as safe as you might think, and the potential problem still remains.
 
longjohnsilver said:
Isn't it a pretty widely held understanding that many commercial vessels can, and do, filter out the AIS broadcast from leisure vessels, so maybe it's not as safe as you might think, and the potential problem still remains.
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Can you give an actual reference for this feature? I have tried to find AIS equipment specifications that require this functionality, or equipment handbooks that explain its use. So far no joy. Perhaps it only is used in the Solent.
 
I believe (and I could well be wrong) that the commercial equipment allows this to be done. I expect someone will be along soon to give more info.
 
MapisM said:
Firstly, in my understanding of the above quotes, I'm not sure that the "must always be on" bit descends univocally from the previous explanations.
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benjenbav said:
My view is that the key phrase is "proper use" of radar in 7().
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Thanks for the digging Piers. Yes MapisM, the conclusion doesn't follow from the statements made by the MCA guy. He is self evidently mistaken in his legal thinking. The ONLY section of Colregs that can conceivable create a "radar must always be on, regardless of circs" rule is 7b, exactly as BJB says. No other clause can possibly mandate it. I'm firmly of the view that 7b does not contain a "radar always on" rule, for several reasons that I won't bore you with

Huge respect to the late Capt Avis, but I think even he would have agree that despite his outstanding navigational achievements he didn't ever purport to have particular knowledge of law and fine points of interpretation. And just to be clear, I agree Colregs mandate use of radar in particular circumstances; I'm merely saying that having radar off is not always unlawful per se, regardless of the navigational conditions
 
This has been an interesting debate. In a way, I'm kicking myself for not having asked for the 'evidence' at the time, but hey, one lives and learns.

Apart from this specific, I've often wondered what happened to the simulator Robert had commissed and owned. It was apparently certified for training and certification up to a 3,000 ton ticket. He was able to set scenes as you planned and carried out your nav plan form A to B. He was able to create other vessels and have their sound signals blasting away, getting louder the nearer they were. Quite gripping as a training tool.

Ah well, maybe someone knows. All the best to one and all. As I said, a good debate.
 
RAI said:
Can you give an actual reference for this feature? I have tried to find AIS equipment specifications that require this functionality, or equipment handbooks that explain its use. So far no joy. Perhaps it only is used in the Solent.
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Don't have time to search now, but links have been posted in Scuttlebutt to the manuals for Furuno ECDIS displays that have the "hide class B" feature.

Pete
 
prv said:
Don't have time to search now, but links have been posted in Scuttlebutt to the manuals for Furuno ECDIS displays that have the "hide class B" feature.

Pete
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I did download the manual to the Raymarine AIS 950 Transponder. (Class A.) There is nothing in the manual about filtering out Class B transmissions. It does have a bit about some Class B receivers not being able to receive certain types of messages and so ships Captains should not rely on Class B receivers receiving these types of messages. I also noticed there was a 'Tanker mode'.
 
I may be wrong but here is my take on filtering out vessels.
There are two types of target. Active and Sleeping.
When a target enters the guard zone it is automatically an active target.
It is only possible to filter out sleeping targets.
Selecting which sleeping targets to filter out can be done individually or on mass,
i.e. It is possible to filter out all Class B sleeping targets.
An active target displays vector, heading info etc on the display. An unfiltered sleeping target will just display an arrow.

I may be wrong.
 
Thanks prv.
If I understand 4.12.3 correctly, Class B can be removed from the alarm but that does not imply that it's symbol is removed from the screen. However, in 4.3 it does appear that even all targets can be removed from the screen and Class B as a group as well. I wonder how often this is used on the open sea.
 
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