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Old 25-10-2012, 06:26   #46
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Re: Type "A" AIS for Yachts?

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Originally Posted by Thumbs Up View Post
The commercial boats CAN NOT see you with the class B AIS.
No offense, but this is simply and completely untrue.

There are some (not all, probably not even most, but some) AIS devices that can filter out class B signals if the operator so chooses. If that filtering is not active, or if they have one of the AIS devices that does not have the option for this sort of filtering, then they WILL see you.

Of course, if you are a 30' sailboat and they are a 3,000' supertanker then they may choose to ignore you even though your boat shows up on their AIS device. They probably cannot stray from the channel, nor stop or turn quickly enough to avoid you, and so they will assume that you are going to stay out of their way. Not a completely unreasonable assumption on their part.

And that's really the point. Don't ever assume that you are safe just because you're sure that your AIS signal is getting to that giant ship bearing down on you. In fact, if you are going to start making assumptions, then the only safe assumption is that they can't see you. Take evasive action early enough that there is never any question of conflict and it won't matter if they see you, and it won't matter who might have been the stand-on vessel had you held your course.
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Old 25-10-2012, 07:31   #47
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Re: Type "A" AIS for Yachts?

Many of my friends are cargo ships officers.

They all say Class B is visible and well enough in advance to take effective action.

barnakiel
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Old 25-10-2012, 19:30   #48
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Re: Type "A" AIS for Yachts?

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Originally Posted by gjordan View Post
This thread has been mind boggeling in the amount of information given. Could someone give me a rough idea of how much it would cost to outfit a small to medium size sailboat with a new radio and class b transponder? Or can an older radio be tied to a class b transponder. I am not a big fan of high tech stuff ( I love my sextant) but AIS sounds like a really good safety factor. Any help will be welcomed.____Grant.
pick your radio and AIS pricing here. I am really fond of our Watchmate 850. Low power and stands alone or can network.
Welcome to Milltech Marine - your AIS experts
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Old 25-10-2012, 20:13   #49
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Re: Type "A" AIS for Yachts?

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Originally Posted by barnakiel View Post
Many of my friends are cargo ships officers.

They all say Class B is visible and well enough in advance to take effective action.

barnakiel
We have a type B Raymarine AIS500 installed. This summer while sailing from Italy to Tunisia, in situations we have been the stand-on vessel, it was pretty obvious, that the biggies altered course very well in advance.
I do not see any rason to install a class A type on our boat.
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Old 25-10-2012, 21:19   #50
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Quote:
Originally Posted by Nicholson58

pick your radio and AIS pricing here. I am really fond of our Watchmate 850. Low power and stands alone or can network.
Welcome to Milltech Marine - your AIS experts
Thanks for the link and thanks Dockhead for the post. Quite the informative thread, I feel educated enough now to also make an informed choice.
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Old 25-10-2012, 21:46   #51
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Re: Type "A" AIS for Yachts?

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Folks, there is no such thing as a Class-B Receiver! There are Class-A transponders, Class-B transponders, and AIS receivers. The receivers will receive both Class-A and Class-B signals.
Good point, Paul.

As our resident communications guru, what do you use on your boat?
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Old 26-10-2012, 00:39   #52
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Re: Type "A" AIS for Yachts?

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Good point, Paul.

As our resident communications guru, what do you use on your boat?
I'm junior-guru status at best, and I'm not really a cruiser, but here's my setup (and some comments):

Currently I have a ACR NauticastB Class-B transponder. The dedicated antenna is mounted on my upper spreader, and the dedicated GPS antenna is on the stern rail, next to my chartplotter's GPS and the Iridium satphone antennas. I have a "stealth switch" that disables the transmitter, although I never use it. The ACR transponder draws about 0.3A @ 12V.

The transponder feeds my NMEA-0183 Shipmodul mux, which combines data from my other NMEA instrumentation and feeds it all the Furuno Navnet 3D chartplotters, and my ship's computer. The AIS also feeds my Standard Horizon "Matrix" 2000 VHF.

The VHF currently gets it's GPS input from the chartplotter, which isn't optimal since I often shut off the chartplotters for power-saving when at sea. The VHF *requires* GPS input on a different port than the AIS, and the GPS has to be at 4800 BPS. It's a stupid design, but the Matrix doesn't recognize the GPS data embedded in the high-speed AIS transponder output. The latest Matrix version may have fixed this oversight. Anyway, when I have the chartplotter off, the Matrix AIS function is disabled (as is some of the DSC functionality) because it isn't getting GPS data. I think I can reconfigure my NMEA mux to make the system work properly, but haven't gotten around to it. Once I get this sorted out, it should be a very low-power AIS solution.

When at sea, I actually use my NavMonPc program for AIS (and other) monitoring. I run it on a low-power "netbook" or similar, which burns less power than the chartplotters and has (in my humble opinion) a much superior AIS feature-set. I use Expedition for charting and weather routing on the computer.

I use the chartplotter when I need radar, or am close to land.

This system is an upgrade from two previous AIS configurations. I started out with a SR-161 single-channel receiver, with a stern-rail-mount antenna. This fed NavMonPc. I actually first tried out the NASA AIS receiver, but was unhappy with that unit. Later, I upgraded to the dual-channel SR-162 receiver. The dual-channel unit was definitely quicker to receive the static ship information, but there was little practical difference in basic dynamic (position, course, speed) acquisition.

In practice, I find AIS to be helpful. It lets me see ships (usually) well beyond my visual horizon, and prepare for any near approach. I do use a hand-bearing compass to verify our relative courses. I have had ships alter course because they saw my Class-B signal, and have had them hail me by name because they wanted to chat (this is on the high seas, not in the shipping channels). Of course knowing the ship's name makes it much easier to get their attention when calling in VHF.

The Matrix VHF is a good unit, but I find the user interface to be a little difficult. I have to confess that I haven't yet learned how to use most of the fancy features.

I think for a fairly stand-alone, low power, AIS solution, the Standard Horizon Matrix radio and a Class-B transponder (and possibly a dedicated GPS for the radio) is a good bet. The Vesper transponder also looks very good, and I believe it has a superior user interface.

I also think that you get perhaps 90% of AIS benefit with just a receiver. A transponder does have some advantages, which is one reason I have one.
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Old 26-10-2012, 02:14   #53
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Re: Type "A" AIS for Yachts?

For whatever it is worth, I think I've decided to go with Class "B". Two reasons: (1) I think it will be a PITA programming voyage data every time I go out; (2) I just got the first quote on my new sails -- over $50,000 without VAT (!). I'm sure I'll find a better deal than that, but I'm starting to doubt my $30,000 line item for sails in my refit budget. So I'm in budget shock and suddenly not feeling like splashing out on anything which is not strictly necessary
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Old 26-10-2012, 02:54   #54
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Re: Type "A" AIS for Yachts?

The new Vespar Watchmate uses a colour screen I believe.


http://www.vespermarine.com.au/marin...e-vision.html/

This one has wifi etc and may be the one you are looking for Nigel.

The WatchMate Vision AIS Transponder includes built-in WiFi, NMEA 2000/0183, GPS receiver and GPS antenna.
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Old 26-10-2012, 05:41   #55
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Re: Type "A" AIS for Yachts?

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For whatever it is worth, I think I've decided to go with Class "B". Two reasons: (1) I think it will be a PITA programming voyage data every time I go out; (2) I just got the first quote on my new sails -- over $50,000 without VAT (!). I'm sure I'll find a better deal than that, but I'm starting to doubt my $30,000 line item for sails in my refit budget. So I'm in budget shock and suddenly not feeling like splashing out on anything which is not strictly necessary

Prob'ly take me 25 years of high-speed cruising to burn $50K in diesel...



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Old 26-10-2012, 06:22   #56
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Re: Type "A" AIS for Yachts?

The filtering debate is starting to sound more and more like an anchor discusion.

The USCG and IMO require that ALL vessels with installed AIS have it operational, unless it compromises security. So anyone filtering AIS targets runs the risk of violating the rules and if possibly losing their license.

For everything you ever want to know about AIS, go to the USCG Web Site for AIS
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Old 26-10-2012, 06:24   #57
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Re: Type "A" AIS for Yachts?

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Prob'ly take me 25 years of high-speed cruising to burn $50K in diesel...



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Sailing is not necessarily cheaper than motoring -- no argument from me!
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Old 26-10-2012, 07:04   #58
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Re: Type "A" AIS for Yachts?

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Prob'ly take me 25 years of high-speed cruising to burn $50K in diesel...



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You should use your boat more...
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Old 26-10-2012, 07:39   #59
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Re: Type "A" AIS for Yachts?

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I'm junior-guru status at best, and I'm not really a cruiser, but here's my setup (and some comments):
That's a point I might argue. Anyone who googles Paul's boat's name, Valis, will discover that Paul has served as the communications boat for the Pacific Cup race to Hawaii for the past three races.

I would argue further that anyone who has sailed to Hawaii and back at least four times in the same race is a cruiser, even if he was racing during one leg of the voyage.

(Thanks for the detailed response Paul.)
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Old 26-10-2012, 08:02   #60
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Re: Type "A" AIS for Yachts?

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Sailing is not necessarily cheaper than motoring -- no argument from me!
Owners of large racing boats often request their delivery crews to motor the boat to its next venue because "diesel is cheaper than sails."

Of course, to remain competitive many racers purchase a new suit of sails every other year.
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