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Thread: A.I.S

  1. #1
    Join Date
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    Default A.I.S

    I'm out of the cruising threads because apparently 'real cruisers' don't use modern technology or sail anything bigger than 12 ft long. They only use sextants and paper charts and just crash on up to nations quite prepared to arrest you and impound your boat if you don't follow the rules of advance notice, etc.

    But here's one little example of AIS in action nearly this time last year , albeit after the excitement.
    500 miles south of Fiji, about 500 from home thereabouts..





    I didn't want to go behind it because , well, you just don't know what they have out the back. We never did get a response but all the calls we made must have at least got their attention eventually , because they did alter course to go behind us, which we appreciated.

  2. #2
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    Default Re: A.I.S

    Our particular unit is also free standing below in that it has its own screen. The anchor watch function is really useful in a blow because I can read it from the bunk. It has the usual alarm, but a collateral advantage is being able to see where the boat has been... we used this one to unwind from a rock


  3. #3
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    Apr 2010
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    Default Re: A.I.S

    I fitted one for our trip from Hobart to Adelaide, but in the usual rush of things failed to get it sorted before we left. Bruce's nephew Matt got it sorted for me a few months ago, and now from our berth at North Haven we can see who is coming and going all over the Gulf and Port Adelaide. Very neat.

  4. #4
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    Default Re: A.I.S

    I don't have a sextant though.

  5. #5
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    Apr 1999
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    Hyannis, MA, USA
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    Default Re: A.I.S

    I've fitted an AIS transceiver to Meg. It's integrated with the GPS display. Can't wait to start playing with it.

    I am one of those who does a DR plot first, then visual bearings if visibility allows, then GPS. I do this a great deal in fair weather and in waters I know well, could easily sail from memory. It's all about keeping all skills sharp and related. Then if conditions cause one' or two to be out, I'm still good.

    The AIS is far better than a radar reflector at both alerting commercial or other AID equipped vessels of your presence and presents you with information far less confusing and ambiguous than radar as to what's headed your way.

    There is nothing wrong with choosing traditional methods any more than there's nothing wrong with sailing a plank on frame boat. What's wrong is to feel that by so doing one is morally superior.

    The other side of this coin is, of course, the weekend warrior who treats going to sea as a video game. Such nautical hazards are beneath contempt.

  6. #6
    Join Date
    Dec 2001
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    Northern NSW Australia
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    Default Re: A.I.S

    Brilliant tech !!!
    '' You ain't gonna learn what you don't want to know. ''
    Grateful Dead

  7. #7
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    UK. Cornwall, Suffolk.
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    Default Re: A.I.S

    I was gob-smacked to hear that rigs don't fit them. Granted the radar signature is huge, but the risk of a ship collision with 500 BarG of natural gas flowing is what everyone fears most while aboard. I would have thought the cost / risk value of such a system would be worth it, considering what a tired officer on the bridge of a large ship can misinterpret on his / her radar screen in heavy weather.

  8. #8
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    Grosse Pointe, Michigan, USA
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    Default Re: A.I.S

    We installed an AIS-equipped VHF radio a couple of years ago. Oddly, the radio was less expensive than an independent AIS receiver alone. The AIS option added about $100 to the radio cost. The radio can transmit your own GPS coordinates at the push of a button, but doesn't transmit constantly, as a transceiver does. It displays all the vessels in the area broadcasting AIS--which is all the commercial traffic. It still calculates a collision course within line-of-sight range, which can be set to sound an alarm. All in all it's the most effective anti-collision device I've seen, not the mention the lowest cost.

  9. #9
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    Default Re: A.I.S

    ^ Sounds good.

    I'm going for a dedicated AIS transponder on Kate; I'd like others to see me.

  10. #10
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    Default Re: A.I.S

    Quote Originally Posted by lupussonic View Post
    ^ Sounds good.

    I'm going for a dedicated AIS transponder on Kate; I'd like others to see me.
    The system is basically just sending and receiving a vessel's GPS data on a dedicated VHF channel. I don't know why all of them aren't transceivers. The radio I bought does send out the GPS, but you have to hit a button to do it manually. I would not be surprised if eventually they add an automatic transceiver to the system, since all the electronics are there already. Might note that the radio is self-contained, includes a GPS unit, a tiny screen display, and built-in GPS antenna. A mast-mounted VHF antenna completes the system. The data goes to a separate computer display as well, which includes a chart plotter.

  11. #11
    Join Date
    Sep 2007
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    Default Re: A.I.S

    All those those 12' cruisers can load a marine traffic app on their phones so they don't get run over. https://www.westmarine.com/WestAdvis...raffic-AIS-App

  12. #12
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    Default Re: A.I.S

    My experience with ancillary screens or devices is there's an issue ensuring they're charged enough when you want them. For something that needs to be on 24/7 to be of value that isn't really good enough. It can be done of course and we do have the apps that pick up the AIS data from our vesper, but that would be mostly for a periodic check on off, for convenience.
    I also found that even plugged in, some programs or apps use more power than what is going in, so management of the things becomes another task. Google earth on an ipad for example, is power hungry, especially since you have the screen on max for daytime nav through the reefs.
    So they're great, with issues, and that makes them useful for backup and specialised shorter time tasks. No substitute for a proper unit wired in.

  13. #13
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    Mar 2008
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    West Wales, UK
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    Default Re: A.I.S

    I have just circumnavigated Britain on a boat equipped with an AIS transceiver and with AIS info displayed on the chart plotter. Despite being inherently sceptical of high tech gizmos (more to go wrong, dependency culture,etc), I was sold from the moment when we were crossing Belfast Lough in thick fog and were plotting the progress of a Dutch tanker and its CPA on both radar and the plotter (AIS) _ only to have them call us up to confirm whether we were sailing or under power and to tell us that they were altering Couse to pass astern.
    They passed about half a mile astern; we could hear them clearly but saw nothing !
    Nick

  14. #14
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    Default Re: A.I.S

    My experience with ancillary screens or devices is there's an issue ensuring they're charged enough when you want them. For something that needs to be on 24/7 to be of value that isn't really good enough. It can be done of course and we do have the apps that pick up the AIS data from our vesper, but that would be mostly for a periodic check on off, for convenience.
    I also found that even plugged in, some programs or apps use more power than what is going in, so management of the things becomes another task. Google earth on an ipad for example, is power hungry, especially since you have the screen on max for daytime nav through the reefs.
    So they're great, with issues, and that makes them useful for backup and specialised shorter time tasks. No substitute for a proper unit wired in.
    Spot on.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  15. #15
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    Default Re: A.I.S

    Quote Originally Posted by John B View Post
    My experience with ancillary screens or devices is there's an issue ensuring they're charged enough when you want them. For something that needs to be on 24/7 to be of value that isn't really good enough. It can be done of course and we do have the apps that pick up the AIS data from our vesper, but that would be mostly for a periodic check on off, for convenience.
    I also found that even plugged in, some programs or apps use more power than what is going in, so management of the things becomes another task. Google earth on an ipad for example, is power hungry, especially since you have the screen on max for daytime nav through the reefs.
    So they're great, with issues, and that makes them useful for backup and specialised shorter time tasks. No substitute for a proper unit wired in.
    The GME AIS transceiver I've bought but still haven't installed, has no screen so I'm supposed to link it to the chartplotter. I wonder if that'll be an issue?

    Rick

  16. #16
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    Default Re: A.I.S

    AIS and Radar are of course two different animals and cannot be compared directly. But I’m a bit concerned with those who say AIS is better at collision avoidance than radar. Radar sees everything, AIS receivers only see who is transmitting. My house has a view of the shipping lanes and I am amazed at the number of vessels supposedly required to transmit, don’t. Many are just scofflaws . But also military vessels do not transmit so a 1000’ carrier will show up pretty well on radar, but AIS not at all. And tug and barges may be several hundred feet long, but the tug may be too small to require AIS and even if they do, the barge doesn’t. If I could only have one, it would be radar.

  17. #17
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    Default Re: A.I.S

    Both are probably best, but AIS is so cheap, a receiver at any rate, why wouldn't you have one? Just dont trust it to see everything, obviously. When I had radar, by the time i had it tuned to cut out clutter and just show real targets, I could usually see the vessel before radar picked it up. Handy to know the vessels heading and speed, but otherwise the Mk 1 eyeball was pretty much as good. No fog of course.

  18. #18
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    Default Re: A.I.S

    Radar sees everything,
    No, it doesn't.

    Radar cannot see the vessel behind the ship in front of you, the vessel running between the jetties at low tide, the vessel around the other side of a point of land, etc. AIS can " see," all of those, to the extent the VHF signal isn't blocked.

    AIS, as you say, only shows vessels so equipped. That means most commercial vessels, but just a small percentage of recreational vessels.

    Radar can show you the navaids, the seawall, the mooring bouys, the shoreline, all of which AIS is blind to. Radar will show you a flock of birds indicating ( possibly) feeding fish. Radar can show thunderstorms.

    AIS lets you know at a glance what the target is, what its name is so you can hail it. With Radar you have to guess the target's identity in many instances.

    If I could only have one, it would be radar.
    Me, too.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

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