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Old 16-05-2013, 20:35   #121
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Re: Please turn your AIS off when docked/moored/anchored

Evans is against guns?

grrrr...
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Old 16-05-2013, 21:56   #122
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by Jammer Six View Post
What is "AIS"?
^^^^^
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Old 16-05-2013, 22:19   #123
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Re: Please turn your AIS off when docked/moored/anchored

Please, we can disagree without being disagreeable. I'm seeing too much nastyness from a few people here. Evans has earned his status, and continues to demonstrate, by word and deed, that he is someone we might want to listen to. If you can't appreciate that fact, I suggest the problem is with you, not him.

That said, I think he's a bit off base here. It would be nice if I didn't have to ignore AIS targets from boats that are safely tied up in their slips as I sail down the fairway, but this issue is not going to get any better. Also, there are other close-quarter situations where a legitimately-transmitting vessel that is no threat will also trigger an AIS alarm. I think in close quarters we need to turn off the alarm, at least until improved alarm algorithms are developed. This is the practical solution.

And if you are concerned about AIS targets cluttering your chartplotter / display, then that is a display setting or design problem, not an AIS problem. Complaining about Class-B targets from small boats seems pretty silly. So it's OK to run those down, is it? If your screen is crowded, don't blame the boats, fix the screen, or accept that it just isn't a suitable tool for that task you are asking it to do.

Ans if Evans disagrees with me, I will listen to him and consider what he says, as I would do for anyone else, and as he would do for me. This is how it's supposed to work.
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Old 17-05-2013, 02:46   #124
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Re: Please turn your AIS off when docked/moored/anchored

Suggest what you wish, Elliott.

You can be impressed by whatever you wish. Those are your standards.

I read what he said, and if that's the standard here, (and your comments, coming from a moderator seem to suggest that that is, indeed, the case) what I said stands-- I'm disappointed.

Have a nice day.
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Old 17-05-2013, 02:58   #125
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by cheoah View Post
Fine I get the uses in the anchorage. So everyone knows who you are, and can call you without dinking over to say hi, or can see you drag anchor -as if they would see that on AIS first. OK, maybe that's useful, but kind of a stretch with my anemic imagination.
From the recent Anchor light thread were plenty of folks who said they navigated their way through mooring fields on Radar, so for that I think AIS might be very useful - for both boats!

Perhaps the prudent (and seamanly?) thing to do in the situation that OP describes (of too much gizmo info) is to broadcast a request by VHF for folks who are moored to turn off their AIS until they have passed / docked as is getting confused. Likely that if folks have AIS switched on at the dock that VHF also on, and if not for some then in a Marina easy enough for folks to walk around and let others know that someone approaching is in difficulty.
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Old 17-05-2013, 03:36   #126
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by David_Old_Jersey View Post
From the recent Anchor light thread were plenty of folks who said they navigated their way through mooring fields on Radar, so for that I think AIS might be very useful - for both boats!
Not so sure about that, I find ais massively useful for watching the big boats, very seldom you'll find one not transmitting, but smaller craft you're never sure if they will have a transmitter or not so it's probably a very incomplete picture. Could see where it might be very useful for letting a friend on a boat see just where you are anchored if he comes in to a big anchorage after you.

Google earth can be handy though


Quote:
Likely that if folks have AIS switched on at the dock that VHF also on, and if not for some then in a Marina easy enough for folks to walk around and let others know that someone approaching is in difficulty.
From spending a bit of time on marine traffic I get the impression that a fair majority of the docked boats transmitting haven't moved for quite a while, presumably with no one onboard. Which, imho, is a bit daft. Few are mega yachts with systems which might stay fired up.

But we've been there already

I'm with the earlier poster & never bother with the alarm unless way offshore with a ship a week. The relative heading vectors, now they are some wonderful pixels of great use

Slight drift, but here's a list of country codes for MMSI numbers, first 3 numbers of the MMSI. So you can save onto your tablet & find what country the ship 13 miles away is from. Not much else to do most of the time out there. Until raymarine load angry birds onto their chartplotters.

Table of Maritime Identification Digits
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Old 17-05-2013, 03:56   #127
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Re: Please turn your AIS off when docked/moored/anchored

Evans appears to have been largely wasting his time, in posting an appeal to sailors to consider putting the common good ahead of their individual convenience.

Many other people have already made this point, however they think that reflects badly on the OP. I'm mystified how they get there from here.

I hope it means something along these lines:

Perhaps a majority of the people who recollect that there is such a thing as the common good, and who believe that it trumps narrower considerations of self interest, have better things to do with their time.
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Old 17-05-2013, 04:01   #128
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by colemj View Post
Is it possible that Evan's issues could be solved by a little better understanding of his equipment or a slight change in his tactics in using it?
Guys I know perfectly well how to use my equipment. When there are not too many 'false' targets I can 'mute' each one and still leave the system fully alert for real targets. When there are 50 false targets (as in this case) I cannot mute each one (takes too much time while I am trying to sail the boat thru tight waters), so I did in fact switch the filtering, but that degraded the system ability to give me its full alert capability (and yes, there was in fact a slow moving ship in the channel up in front of me - unusual situation this time, it was a coal carrier being blocked by an environment activist vessel trying to prevent them from unloading the coal, in a narrow channel with a decent current, tricky situation). The system is designed to be able to give us an alert in plenty of time so that we can call the target on VHF and we can discuss what our intentions are and how to pass. I would prefer not to have to be fiddling with this unit doing micro filter adjustments as I am sailing in from offshore into a more busy environment - I am usually busy enough as it is in that situation.

I have explained why I think docked class B units should turn off their systems - simply because they are degrading a shared collision avoidance system. And that you could help out the community of seamen by turning the thing off, and not lose anything important.

I have heard no good reason from any of you why they should keep their AIS systems on while docked - and no, the fact they chose to wire it into one common 'NAV' switch is NOT a good reason to degrade an important shared collision avoidance system. So can any of you give me a good reason why you are degrading an important shared safety system?

I might note that just previously I was sailing by NY city and there was so much AIS noise that my unit could not find a transmission slot for about half of its scheduled broadcasts. (And no that is NOT my unit's fault, which is one of the best - excellent Vesper unit, highly recommended).

And give the 'famous' topic a rest. I am just a simple cruiser, just asking for a 'clean wake' from my fellow seamen in the cruising community. I have made a logical argument about a safety system which has nothing at all to do with how much experience I have . . . respond to the argument. We have a 'newish' technology here without well established protocols on use . I think some of you don't understand the impact of how you are using it, and might want to rethink what you are doing. It is only going to get worse, if it continues as is, with people unnecessarily leaving their systems on.
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Old 17-05-2013, 04:31   #129
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Smile Re: Please turn your AIS off when docked/moored/anchored

Hi Guys, I have just finished reading ALL the reports. What a lot of confliction!

here is my two penny's worth.

AIS should be on whilst sailing also when at ANCHOR it may be advisable to leave it on ( you will pick up the ones that may just be going too close for comfort OR even dragging.)

When safely in a Marina the AIS "MUST BE TURNED OFF!!!

Fair winds
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Old 17-05-2013, 06:13   #130
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by estarzinger View Post
Wow I am gone for a day and there are 6 pages!

I have a vesper AIS, and it has all sorts of filters. I was using what they have preset as the "coastal sailing' set of filters.

I have tried it and I do NOT like filtering out slow moving vessels (say under .2kts) because I have found both slow moving fishing boats (say when picking up their pots) and slow moving ships waiting for a birth time or pilot. I prefer it be allowed to alarm for those, and then I don't think there is a way to separate out the (class B) moored boats - would be delighted if someone can tell me otherwise.

The 'coastal sailing' set of filters has an appropriate alarm circle range for dealing with ships moving at 15kts. I do not want to reduce that circle or it will not give me (what Vesper considers) the 'best practice' amount of warning.

I personally see zero reason for pleasure vessels with class B AIS to be transmitting while docked or moored in Newport harbor. I would suggest you are wrong if you think that's going to stop some idiot from running into you - that idiot probably will not have AIS, and if he does probably will not be paying it much attention (if he is bad enough to hit a moored boat). This (the AIS frequency) is a public commons and you are reducing its usefulness and value by clogging it up with unnecessary collision alerts when you don't need to be - it's simply being a bad member of the community - in my opinion.
I have a Vesper also. You have three choices for alarm settings, offshore, coastal, and harbor. You need to disable all the alarms in the harbor profile and then switch to it when you enter one. In Coastal, you should have the profile alarm set to filter out all non-moving or slow moving vessels, say under 1 knot. As far as turning the unit off, no way. It is by far the best anchor alarm I've ever seen. Very accurate and low power consumption. I could turn off the signal transmit but would then need to make sure I turn it back on when leaving. So, really, imo, operators need to learn to make due, not expect others to change for no rational reason.
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Old 17-05-2013, 07:02   #131
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Re: Please turn your AIS off when docked/moored/anchored

Does anybody know what sort of numbers of vessels it takes to start clogging the system up for the class B's? Without any technical knowledge in this area it would sound like their are 4500 slots or so in the two AIS channels. I am not sure if the slot numbers are reduced for class B or not?

If this is correct then for 6 minutes we get 27000 slots.

In this time period a class B doing less than 2 knots (ie tied up in a marina) would use a total of 4 slots (two for its 3 min position reports (msg 18) and two for its static reports (msg 24a and 24b). This gives us a maximum of 6750 Stationary Yachts using the system if none of them are class A's and none are moving?

If the class B's are moving each vessel uses 14 slots per six minutes allowing a maximum of 1928 moving yachts to use the system before it starts to slow?

Adding class A's into the mix would considerably reduce the number of slots available as does any polling and interrogating by shore stations, plus any garbled slots. One report suggested a random mix of 22 ships with class A AIS and shore station interrogation could use 20% of the capacity! (look at 3.2.4 Creation of a traffic load scenario in this document)

Are the idle class B AIS units (on the boats tied up in the marina) being interrogated as well? If so they could significantly drive up the number of slots being used?

As I said I have no knowledge of the system other than what a quick google can provide, please correct any errors that I am sure to have made. I did this to try to get a rough idea on the numbers involved. But the figures (if correct!) do support Evans observations that in a busy port like NY the system could start to slow down, certainly for class B users who have to fight to find slots to fit in around the growing class A use.
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Old 17-05-2013, 07:16   #132
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The slow downs that are reported now and then are caused by the plotter software or by the alarm routine software, not by the system design itself. The important thing is to have your unit switched ON so that it gathers all info about the ships you encounter before you are even close to them. When you wait and switch it on when a ship suddenly comes up, your display will be empty and it can take a while to get all data in order.

About AIS while docked: here in Shelter Bay Marina they can tell new arrivals to enter the marina and proceed to D dock which is the first dock beyond Jedi and then go into slip x etc. It helps.

About governments able to track us: they get very anxious when Jedi knights go under their radar so we switch it on and they can relax a bit again

We also suppress alarms for speeds under 1 knot except when we are off-shore. We also switch to manual targets with ARPA for the same reason, after deciding it was easier than asking others to suppress their radar returns :thumbs:
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Old 17-05-2013, 07:17   #133
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by Palarran View Post
I have a Vesper also. You have three choices for alarm settings, offshore, coastal, and harbor. You need to disable all the alarms in the harbor profile and then switch to it when you enter one. In Coastal, you should have the profile alarm set to filter out all non-moving or slow moving vessels, say under 1 knot. As far as turning the unit off, no way. It is by far the best anchor alarm I've ever seen. Very accurate and low power consumption. I could turn off the signal transmit but would then need to make sure I turn it back on when leaving. So, really, imo, operators need to learn to make due, not expect others to change for no rational reason.
First the boats in Newport were NOT anchored. They were either at docks/slips or on town moorings. They did NOT need to have anchor alarms on.

Second, As I have said twice above, I would prefer not to filter out slow moving targets, because some of those are actually underway and a collision risk. And in fact in this particular case (as I noted in the post above) there was in fact a slow moving (almost stopped) coal ship in the channel. The point of the system is collision avoidance and some of these 'currently slow moving' targets are actually in play (As I mentioned before, finishing boats picking up traps and ships burning time for pilots or dock schedule, and other situations).

I still have not heard a good reason why you should not turn your unit off when docked or on a mooring. I am still waiting to hear one good reason not to turn the system off in this situation (Which was the Newport situation).

And if it is the nice anchor alarm you want to use (When anchored) that's fine, but it seems to me that you should go to the very small effort to put the unit into silent mode so as not to jam up the collision avoidance system. By not doing that you are degrading a shared safety system just to save yourself about 5 second of work. You say you don't want to have to remember to put the system back into transmit mode, but because of that you are forcing me to toggle filtering while out navigating under sail and not get alarms for potentially important targets and also to have to remember to remove the filtering. . . that seems . . . perhaps selfish.

To me this is just like tossing plastic trash in the ocean. You are tossing trash into an important shared collision avoidance system.
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Old 17-05-2013, 07:21   #134
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by Snowpetrel View Post

Are the idle class B AIS units (on the boats tied up in the marina) being interrogated as well? If so they could significantly drive up the number of slots being used?

As far as I am aware, AIS is not interrogated, it just transmits, and any receiver in range will pick up the data.
Like the OP, i would prefer it if boats with Class B, tied up at the dock would turn the transmit function off when safely at the dock. Coming into a busy harbour, if I start to get a lot of alarms from Class B, I'll just filter the lot out if it gets to distracting. The hope is, we remember to remove the filter when back at sea. So from a big boat perspective, I'd appreciate it if Class B users would turn the transmit off when safe to do so
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Old 17-05-2013, 07:35   #135
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Re: Please turn your AIS off when docked/moored/anchored

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First the boats in Newport were NOT anchored. They were either at docks/slips or on town moorings. They did NOT need to have anchor alarms on.

Second, As I have said twice above, I would prefer not to filter out slow moving targets, because some of those are actually underway and a collision risk. And in fact in this particular case (as I noted in the post above) there was in fact a slow moving (almost stopped) coal ship in the channel. The point of the system is collision avoidance and some of these 'currently slow moving' targets are actually in play (As I mentioned before, finishing boats picking up traps and ships burning time for pilots or dock schedule, and other situations).

I still have not heard a good reason why you should not turn your unit off when docked or on a mooring. I am still waiting to hear one good reason not to turn the system off in this situation (Which was the Newport situation).

And if it is the nice anchor alarm you want to use (When anchored) that's fine, but it seems to me that you should go to the very small effort to put the unit into silent mode so as not to jam up the collision avoidance system. By not doing that you are degrading a shared safety system just to save yourself about 5 second of work. You say you don't want to have to remember to put the system back into transmit mode, but because of that you are forcing me to toggle filtering while out navigating under sail and not get alarms for potentially important targets and also to have to remember to remove the filtering. . . that seems . . . perhaps selfish.

To me this is just like tossing plastic trash in the ocean. You are tossing trash into an important shared collision avoidance system.
Evens,
All due respect but I am pretty sure that everyone knows how you feel at this point.
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