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Old 17-05-2013, 16:16   #181
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Originally Posted by estarzinger View Post
Wow I am gone for a day and there are 6 pages!

I
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.

That comment is techno mumbo jumbo Evans

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Old 17-05-2013, 16:16   #182
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by conachair View Post
Has anything like that happened here?
It is called "moderating"

JUST KIDDING GUYS! Note the smiley! Let's not be too serious!



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Old 17-05-2013, 16:22   #183
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Re: Please turn your AIS off when docked/moored/anchored

Personally I think it sad that so much of this thread has included ad hominem comments. There has been some useful information here, and some good food for thought.

I think an argument has been made to turn the AIS off when in the slip, and there doesn't appear to be a lot of value to leaving it on, so I will continue to leave it off in the slip. OTOH the original request bundled anchoring with docking/mooring, and a good argument can be made that there can be value in leaving it on in some cases while anchoring, and I will judge that on a case by case basis.

I will not comment about how the tragedy of the commons may or may not apply, other than to note that I expect that many members are quite aware of the impact of overgrazing on English commons to the modern study of economics - this is not a group of folks that should be underestimated.

It seems to me that at the root of this discussion lies a difference in expectation for what AIS will/can do. My expectation is that AIS will alarm in situations where another vessel is on, or nearly on, a collision course and that action by someone needs to be taken. This would not include a fisherman adrift outside the channel a quarter mile away, who might decide to accelerate at some point in the future. That logic would have to extend to any vessel, even at a mooring, that might slip its lines. AIS cannot warn of a change of activity. Of course I want to be aware of any vessel that might become an imminent threat, and AIS can help by identifying a radar blip as a fishing boat subject to sudden changes in movement (or inability to change course and speed), but I do not expect an alarm until a (near) collision is imminent. The OP wrote that he does want AIS to alarm on that fishing boat so that it is brought to his attention as a vessel that might become a threat in the future. Since an automatic AIS alarm doesn't distinguish between a vessel stopped and adrift with one stopped and tied up, he would like others to help by reducing the confusion. I think he is expecting a bit too much of the AIS system, but I also think there is a valid point there.

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Old 17-05-2013, 16:25   #184
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by Exile View Post
There seems to be conflicting information about whether large commercial shipping actually monitors Class B. Anyone have any more definitive info to share, or does it come down to individual ships? I know they are required to transmit Class A, but are they also required to monitor both A and B?
They are required, in that they are required to use all means available to avoid a collision (etc). I don't know how commonly this is done in practice, but at sea I have been hailed by numerous ships who noticed my Class-B signal, both in crossing situations, and to just say hello.

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My own opinion may change as I gain more experience, but I have assumed that the primary purpose of AIS onboard a recreational vessel was to avoid collisions with large, fast-moving commercial shipping. To that end, I saw little reason for a transmitter and opted only for a high quality receiver which displays & has alarm functions on my helm-mounted chartplotter. Although also having a transmitter certainly wouldn't hurt, I figured that, as a small, slow-moving recreational vessel, it is really my job to make sure I stay out of their way! Whether large shipping routinely monitors Class B obviously weighs on the validity of my decision.
I agree. In a harbor or similarly-tight area, the big ships are usually restricted in their ability to maneuver, so it *is* your job to give them room. On the high seas it's just prudent seamanship and self-preservation to do so, as long as you don't alter course in a confusing or dangerous manner.

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I have also found AIS highly effective when sailing into busy harbors, esp. in reduced visibility. Here again, the primary purpose of the system is collision avoidance, and other reasons previously noted seem secondary, albeit apparently useful to some (e.g., anchor watch, theft, convenience, etc.). Whether one has or correctly enables any particular system's filters, to the extent Class B AIS is transmitting from recreational vessels while tied to the dock, moored, or anchored, it obviously has the potential to denigrate the ability of a vessel underway to decipher actual collision threats.
This is where I'm going to disagree. In my opinion, there is no additional difficulty. The boats are there whether or not they paint a target on your AIS screen. You're either going to hit them or you're not. There will be other "legitimate" targets that appear, and most of these will not be threats either. Your AIS system, including the alarm, has to deal with all of these. And what is not a threat to you, may be a threat to someone going in a different direction. I've not yet seen an alarm that works well in these close-in situations.

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Perhaps there is some utility if one is anchored near a channel or other vulnerable locale, but that can be resolved with add'l anchor lights. In fact, all of the reasons thus far given for transmitting while not underway can be accomplished by other means which do not risk impairing the primary function of the system, i.e. collision avoidance.

For these reasons, I firmly agree with Evans, especially considering that presumably most of the docked boats who have left their transmitters on have done so for no good reason, i.e. the owners have simply forgotten to turn them off. Not sure about the plastic in the water analogy, but perhaps using Ch. 16 for non-hailng/non-emerg. purposes is closer to the point being made by the OP.

As always, I look forward to considering the opinions of more experienced sailors, and will maintain an open mind.
Turning off the AIS transponder when docked is probably a polite thing to do, but that's not going to fix the problem we've been discussing.
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Old 17-05-2013, 16:38   #185
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To try and keep the on an even keel. Class B AIS was designed firstly to be widespread and secondly to be dispensable. That is messages can and do get lost or not transmitted. Once the system reaches a threshold a lot of backoffs occur and random messages get through. The system is inherently self limiting.

Then I have issue entering harbours with alarms ringing anyway , be it MARPA , AIs or anything else. I turn ff a
Arms as they add confusion and I let the mark 1 brain determine things.

I'm quite hey as I've stated that yes with the vessel powered down and locked up there is no need or desire to run your AIS. Of on the other hand you want too , that's fine too. This isn't about " commons".

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Old 17-05-2013, 17:57   #186
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by Kettlewell View Post
Here's a question for any professional mariners on here: what would a commercial ship do when passing by Newport and seeing Class B's all over the place and not moving? I imagine they might filter them out, if they can. Did we ever resolve the question of whether or not commercial ships sometimes filter out all Class B targets, or is it even possible? Seems like all these Class Bs crying wolf might eventually get ignored.
To re-quote this from Nigel. I think he is on a bigger offshore supply/anchor handling vessel.

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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, 18:18   #187
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Re: Please turn your AIS off when docked/moored/anchored

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Just for grins, the USCG ship docked in Charleston, SC leaves its AIS transmitter on 24/7

Perhaps it's best to start with them and work down to the pleasure boats.


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Old 17-05-2013, 18:31   #188
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No comments on this?
Like I wrote before: I have about 150 stationary class-A targets here at the Panama Canal. They are not allowed to stop transmitting. Not even when they are moored and offloading at the container terminal.
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Old 17-05-2013, 19:07   #189
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Re: Please turn your AIS off when docked/moored/anchored

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Like I wrote before: I have about 150 stationary class-A targets here at the Panama Canal. They are not allowed to stop transmitting. Not even when they are moored and offloading at the container terminal.
^^^This, the only time we turn off the AIS is when the vessel is out of commision....

As for Class B vessels turning off when tied up in the marina around Australia? it just isnít a problem yet. Either the majority of the recreational fleet hasn't taken up fitting Class B AIS yet.....or they are turning them off......whatever the case we have never had to use the filter....

But as Nigel says (we are in the same occupation) if Class B's did become a problem i would just filter them out.....problem gone....I much prefer making life easier for myself and not relying on others to do it for me....

I will also add my own boat is sitting up in Bundaberg Port Marina and the AIS is off.....i have absolutely no legitimate reason to leave it on if i am not there...
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Old 17-05-2013, 19:11   #190
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Re: Please turn your AIS off when docked/moored/anchored

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No comments on this?
Hardly seems relevant to the "debate," the substance of which I've lost track of.

I don't have any personal knowledge why large CG & comm. shipping may be required or may opt to leave their transmitters on 24/7. Here are some guesses which seem rather obvious to me, but what the heck do I know:

1. The controlling port authority in busy comm. harbors such as Charleston need to know where all the big ships are, and spec. whether they are docked, underway in channels, or on approach to the harbor itself. I could be wrong, but I don't think control towers at major airports lose track of airplanes just because they are taxiing or parked at the gate.

2. The impact on other marine traffic is far greater when a large vessel is leaving the dock or maneuvering, etc. than when my 47' sailboat is doing so. That's why big ships typically issue securites and sometimes blow horns when they leave the dock and recreational vessels generally do not.

3. USCG vessels have a security perimeter around them, as do cruise ships. Maybe comm. shipping too? Dunno.

4. Seems like all of these factors and others explain why Class A transmitters are required to be kept on by shipping waiting to enter the Panama Canal.

I don't think there's much relevance b'twn the OP's orig. request and comm. shipping, but I must confess I'm really not sold on the utility of using transponders on recreational vessels in any event (but I like having a receiver). As we've just read, careless Class B transmissions will only result in comm. shipping filtering us out, and thereby defeating the primary purpose of the technology as applied to recreational boaters. Besides, leaving it on at the dock sort of reminds me of drivers going down the interstate for miles with their blinker on, no?
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Old 17-05-2013, 19:19   #191
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Re: Please turn your AIS off when docked/moored/anchored

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But as Nigel says (we are in the same occupation) if Class B's did become a problem i would just filter them out.....problem gone....I much prefer making life easier for myself and not relying on others to do it for me....
Can you explain what problem Class-B's would be creating for you, and exactly how you would filter them? I'm honestly curious on both points. There's been a lot of speculation as to how big ships would "ignore Class-B", but I've seen few (if any?) examples of a true ignore capability.
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Old 17-05-2013, 19:29   #192
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Re: Please turn your AIS off when docked/moored/anchored

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Hardly seems relevant to the "debate," ...........
Of course it's relevant. The OP is concerned with too many boats leaving their AIS transmitters on when docked and is mounting a campaign to "educate" boaters to turn them off.

That's pretty hard to swallow when the USCG leaves theirs on. The example I posted is one of many "permanent" AIS targets in the Charleston, SC area. I count approximately 20 docked (not anchored) boats transmitting AIS information right now on Live Ships Map - AIS - Vessel Traffic and Positions
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Old 17-05-2013, 19:30   #193
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Re: Please turn your AIS off when docked/moored/anchored

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Besides, leaving it on at the dock sort of reminds me of drivers going down the interstate for miles with their blinker on, no?
Good one! Or leaving the key on, parking in their garage and leaving the blinkers or flashers on, too.

In many cases we're trying hard to get the 's to actually use them when they're moving!
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Old 17-05-2013, 19:48   #194
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Re: Please turn your AIS off when docked/moored/anchored

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Originally Posted by CarinaPDX View Post
I think an argument has been made to turn the AIS off when in the slip, and there doesn't appear to be a lot of value to leaving it on, so I will continue to leave it off in the slip. OTOH the original request bundled anchoring with docking/mooring, and a good argument can be made that there can be value in leaving it on in some cases while anchoring, and I will judge that on a case by case basis.
Greg
Very good post Greg. If the thread had started as "Please turn your AIS off when docked", I don't believe we would have many reasons to disagree. 90% probably do just because it is a part of the nav equipment group which all together gets turned off.
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Old 17-05-2013, 20:32   #195
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Originally Posted by rwidman View Post
Just for grins, the USCG ship docked in Charleston, SC leaves its AIS transmitter on 24/7

Perhaps it's best to start with them and work down to the pleasure boats.

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Ya this makes sense that coast guard ships have their systems active, and commercial traffic too. I would think this is a pretty Important tool for port authority, and confirmed by Jedi lying near Panama Canal. . Plenty of military vessels don't transmit AIS and I've been surprised offshore NC - Onslow bay and Chesapeake too by patrol boats or small fleet of navy cutters - or whatever they were - it was dark.

Not everyone wants to be seen, but after an all-nighter down the Chesapeake last summer with failed GPS feeding my VHF/AIS receive only unit, I'm eager to install a transponder.
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