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Old 03-18-2015, 03:18 PM   #101
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Ah. Did you mean to imply they had something to do with the Empress of the North incident?

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Koliver was referring to the Queen of the North, which was a BC Ferry. Not the Empress of the North.
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Old 03-18-2015, 05:16 PM   #102
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Ah, so. Got it. Thought that had been a typo or something, since I knew there was an Empress of the North incident


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Old 03-18-2015, 05:47 PM   #103
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...Really, AIS doesn't help with most traffic you encounter. But it helps with the larger, commercial, and essentially more predictable vessels - taking them off of your list of things to worry about.
That's been our experience. The little guys do not have AIS.
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Old 03-20-2015, 10:24 AM   #104
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This came up on another forum.

http://www.professionalmariner.com/A...virtual-buoys/

Perhaps a reason for Marin to install AIS? :-)


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Old 03-20-2015, 11:17 AM   #105
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This came up on another forum.

U.S. Coast Guard begins testing synthetic aids, virtual buoys - Professional Mariner - August 2014

Perhaps a reason for Marin to install AIS
Don't think so. Using virtual AIS positions seems a real benefit to marking things like individual bridge piers as mentioned in the article.

But for enhancing existing navaids, I don't see it as any value to us and the way we boat. We rarely refer to the navaids that are in place now in terms of our navigation. They are all on the plotters and charts we use to navigate with and the only times we use the physical navaids are as visual confirmations of what we already know.

Islands, rocks, and reefs generally don't appear overnight in this region, and we've noticed that the existing islands, rocks, and reefs tend to remain in position for long periods of time.

In the words of a notable Union Steamship Company captain when asked how he remembered the locations of all the rocks and reefs along the BC raincoast, "I don't have to remember where all the rocks are, I just have to remember where they ain't."
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Old 03-22-2015, 10:19 AM   #106
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These new virtual buoys are a pain. They are the location of where the buoys SUPPOSED to be. Often buoys move. (Or in the case of the frozen rivers get dragged). It would be better to have buoys with actual transponders on them. But batteries are an issue.
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Old 03-22-2015, 02:40 PM   #107
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Most all lighted buoys and beacons are now solar powered. So if a buoy is off of its charted location there are two things that may have happened: 1. Channel has changed and buoy was reset, which leads to checking "Local Notices to Mariners" 2. Buoy has been drug off location, broke loss, or is otherwise a stray.
To replace that buoy temporarily in the proper location a virtual buoy would be ideal in my opinion. At least til the CG buoy tender makes its rounds.
Granted that the rocks seldom move, the river and entrance channels do.
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Old 03-22-2015, 04:29 PM   #108
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Also, a couple of months ago someone here also complained that some boats leave their AIS's on when tied up at marinas. Really? That's a problem somehow? Seems like complaining just to complain.
If you have your AIS setup to include an automatic proximity warning, you get to cruise in and out of your marina constantly punching off AIS warnings. My marina alone has 5 or 6 boats that never leave the dock, but broadcast their AIS location 24 hours a day.
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Old 03-22-2015, 05:52 PM   #109
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The constant leaving on ais units clogs the system and degrades overall performance of the reception. It seem many people have the 'I want to be seen (and my boat) mentality' even when tied up at the dock.

Also, all AIS have a function (that is used on commercial vessels) noting the Nav status. Underway, moored, anchored, aground, NUC or RAM. When at anything but underway the pulse rate is slowed down to around 10 minutes. As opposed to underway which is almost constantly updating information By leaving the AIS on at a dock it is unnecessarily cluttering up the system. And I have only found a smattering of yachts that even know about changing Nav status.


Regarding the ais virtual buoy: They clutter up the AI display. I am not worried about CPA or TCPA to the next 7 buoys. I am concerned with the ship 7 miles ahead, and the Tug and Barge between us and where we should meet. I have not found a way to 'shut off' the virtual buoys. (yet)
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Old 03-22-2015, 06:22 PM   #110
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If you have your AIS setup to include an automatic proximity warning, you get to cruise in and out of your marina constantly punching off AIS warnings. My marina alone has 5 or 6 boats that never leave the dock, but broadcast their AIS location 24 hours a day.
Yes, that would be annoying. Our marina has at least 10. However, my system allows ignoring of stationary targets (I turn this feature off during limited visibility), so it's not a problem for me. I guess I assumed that everybody has such an "off" switch also. If you have one, maybe you should try it.

And Cappy 208, I have never experienced too much clutter, nor do I understand a "clogged system". What is the symptom?
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Old 03-22-2015, 06:43 PM   #111
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I have noticed that an aid to navigation with a racon beacon will also clutter up the radar screen but I certainly appreciate the assistance from the beacon. I think that we may all be forgetting the fact that AIS is just another tool to aid in safe navigation. If you think that it is not performing that task, you need only find the power switch to eliminate it from your tool box.
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Old 03-23-2015, 12:27 AM   #112
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Recalling some technical publications from several years ago:

The reason they have several different levels of communication is they realized the system would get overloaded (on the government end) during transmitting and repeating of data if every conceivable AIS was transmitting ALL the time.

They figured that by changing the transmission rates depending on what a particular vessel was doing would give more bandwidth to the system for more important transmissions. Thus the Underway having the most priority (most frequent transmissions) down to the anchored, aground, moored having the fewest transmissions.

From a practical standpoint, my radar screens routinely have 60 to 100 AIS targets on them when I am transiting NY harbor. Now, You and I both know that there aren't 100 boats underway in the Harbor. (ok, Maybe in the harbor, but not underway) But there are literally dozens that are tied up, secure, or simply out of service for the day that are transmitting. Could You or I for all practical purposes notice a difference? Probably not. But there are SO many it clutters up the plotter, and Radar screen unnecessarily.

When I get back into the Harbor I will try to take a screen shot of the Radar screen with the dozens and dozens of AIS targets on it.
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Old 03-23-2015, 12:47 AM   #113
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I leave my AIS on at the dock and will continue to do so.
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Old 03-23-2015, 02:58 AM   #114
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As more boats have AIS, more will be filtered/not-displayed. More than already are, that is.
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Old 03-23-2015, 07:44 AM   #115
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We're still limping along without AIS, as we have no space on the helm for another device and don't like the idea of just having a receiver or we would get the SH VHS/AIS receiver combo, despite its awful display. Our chart plotter came over with Columbus (Raymarine RL80CRC) and only speaks 4800 baud, so no AIS will talk to it. So far I think our only options are to get a Vesper XB-8000 to talk to the iPad or upgrade our chart plotters to Raymarine E80's so we can use most of our existing cabling. But today we are suffering through terrific weather on Eleuthera, AISless, but we rarely see other boats, and if we do they are a ways off.
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Old 03-23-2015, 07:49 AM   #116
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Why leave AIS on at the dock? To show others you have it? To keep from being run into? I don't get it.
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Old 03-23-2015, 08:02 AM   #117
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Why leave AIS on at the dock? To show others you have it? To keep from being run into? I don't get it.

Yes to show others I got it and im proud.
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Old 03-23-2015, 09:42 AM   #118
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There are some additional AIS tidbits in Ben Ellison's latest AIS post.

I had forgotten that Class A is 12W versus 2W for Class B, but this transmission interval chart was new to me:
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Old 04-01-2015, 08:31 PM   #119
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Many years ago I spent some time pushing heavy tows on the Western Rivers. We had a VHF, Whistle with a whistle activated light, and a radar that did not see around a bend in the river. It was common practice to report your position prior to making bends and/or bridges, etc.. on the VHF.
I just went up the Tom Bigbee and was greatly surprised with the impact the AIS system has made on the rivers. No "clutter" due to line of sight, descending (privlidged vessel) would call you by name and know exactly where you were. No more lying about your speed or where you were. A whole lot less VHF traffic. Seemed to work out well for all concerned.
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