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AIS is very Cool

4K views 26 replies 14 participants last post by  TakeFive 
#1 ·
I was messing around with my AIS transponder(Amec Comino 101) this morning and wanted to test the changes I had made. Unfortunately, there were no transmitting base stations active in Portland at the time. If you do not already know, AIS is a boat to boat transmission using VHF frequencies. I can see all the boats around me and they can see me but we are not visible to Marinetraffic.com because none of us are acting as a base station uploading our data to a reporting station like marinetraffic.com.

So I downloaded some base station software, installed and configured it on my laptop which is connected to my active AIS transponder.

Goto marinetraffic.com and select Portland Me as your port. All the vessels you see on that screen are being transmitted from my boat via AIS transponder connected via serial port to my laptop which is connected to the internet via Verizon Mifi.

http://www.marinetraffic.com/ais/def...px?level0=100#
 
#2 · (Edited)
...... I can see all the boats around me and they can see me but .....
That is, you can see all the boats around you which are transmitting an AIS signal.

Depending on where you are, that represents about 10-20% of the boats out there (since most yachts, fishing boats, etc. don't transmit AIS signals) and only a tiny fraction of the things which can hit you and which you can run into (like buoys, pilings, lobster pots, dingies, kayaks, flotsam & jetsum, etc.).

Yeah, AIS is neat and fun, but it's not synoptic....very easy to get lured into the belief that thru AIS you know what's really out there.

Bill
 
#3 · (Edited)
That's how I read it, that Tim meant he could see all the boats around him TXing AIS and they could see him because he was also TXing. Now he can also see them on MarineTraffic.com where he could not before downloading the application that made it possible.. I did not read that as he could see boat without AIS TX...

He's also from Maine, owns radar, and knows how to use it, and does not rely solely on AIS he treats it as an adjunct to radar..;)
 
#4 ·
Thanks MaineSail, you saved me some typing.

My biggest use of AIS is the ability for me to contact other vessels by name so as to communicate intentions. It was very useful on our 2+ week cruise this year. We were contacted directly no less than 4 times to discuss our intentions.

I think I got a little more respect from the big boys because I was transmitting and could call them by name.

My chartplotter has a radar overlay and now with AIS, I can identify some of those returns(of course, only if they have AIS and are transmitting)

And for the record: Marine Traffic only shows vessels(that are transmitting AIS) if there is an active base station. If not, you do not see them so obviously this cannot be used for navigation.
 
#5 ·
Just curious, have you monitored or determined the extent of the power consumption of your transponder? A friend of mine who has one seems to think it's fairly significant, and would add up quickly during a protracted period under sail...

An AIS receiver is a great tool, but personally, I not looking forward to the time AIS transmitters become commonplace on smaller recreational vessels. The potential for clutter, and the need for some sort of filtration, seems inevitable...

I liken AIS transponders on the sort of boats most of us sail to the Xenon headlights being fitted on new cars today... Sure, they may afford a measure of greater security to the guy behind the wheel, but when we reach the point when every vehicle on the road has them, watch out, we'll all be flying blind at night... (grin)
 
#6 ·
Around here 90% of the things that might hit you, and 100% of the things bigger than you transmit AIS. I wouldn't run the ICW anymore without it, as the potential to encounter two barges passing each other and taking up the whole channel as you round a blind corner is very big.

In the open sea it still gives you a measure of protection as the biggest threat is the container ships that the only warning, and a convenient list of ships name. size, and course and speed helps greatly in avoiding them.
 
#7 ·
Maine, Tim...

I know how it was meant. Not trying to pull your chain.

However, you wouldn't believe the number of folks I see these days on the water who haven't a clue....they believe that the AIS display indeed shows them all the dangers and/or they are mesmerized by the specifics of each return....to the point where they're not paying attention to what's ahead of and around them.

In this new age of button-pushing and overdeveloped thumbs, there really is a subtle accompanying belief that what's on the screen is reality. In the case of AIS, it's only a small but unknown fraction of reality! :)

Bill
 
#17 ·
...However, you wouldn't believe the number of folks I see these days on the water who haven't a clue....they believe that the AIS display indeed shows them all the dangers and/or they are mesmerized by the specifics of each return....to the point where they're not paying attention to what's ahead of and around them...
Can you cite specific examples? I agree that this might be a THEORETICAL possibility, in actuality interfacing AIS with a chartplotter, and debugging the glitches when they occur, is not simple. It takes some skill to make it work right, and the process of debugging it reminds the user not to become overly reliant in it.

You seem to paint a picture of a large number of naive users who are fooled into complacency by the technology. I think the technology is complicated enough that its users have to be pretty savvy about its limitations just to get it working.

So educate me. Tell me about the specific examples of people that you have actually seen being mesmerized by AIS to the point that they are distracted by it. Frankly, I usually can't see that well into others' cockpits to tell what they're looking at, and even if I could, I can't read their minds to tell what they're paying attention to. So I wonder how you're able to do that.
 
#13 ·
We have a 30 year old Irwin IC 34. We sail the Bay of Fundy and the coast of Maine. We have VHF, radar, Chartplotter, lap top with FUGAWI and an AIS receiver. I would not leave home without it. Because I already had a laptop and chart plotter, for under $200, the receive was a no brainer!

We have contacted a fair number of ships - it is so easy when you know their name and call sign. Especially when you know the Closest Point of Approach and the Closest Time of Approach. If I see that we will be clear and gone when they come by - we watch them. If we see we are not going to be in a good position 5.3 minutes from now - we call them and inform them that we see them, are monitoring them and that we will pass astern of them.

Eyes, ears, diligence and good electronics, all are "arrows in my quiver" of safe boating tools (wow, did I ever mix metaphors).

Now - I wonder if I should look into that new broad band 3G radar people are talking about?

Rik
IC34
Mystery
 
#21 · (Edited)
You illustrate my point very well. It's just a different perspective.

I assume "my river" means the Delaware River. This is indeed a VERY busy river, with huge ships plying north and south day and night.

I've done the Delaware River and Delaware bay from the C&D Canal to Cape May many times, including at night and in very thick fog conditions. Radar was extremely helpful in the fog, for positioning and for avoiding obstructions.

AIS? Not so much. The ships all follow the ships channel. The channel is very narrow and is very well marked. There's plenty of room outside the ship's channel for a small vessel to navigate without fear of being hit by a ship. Using this strategy allows you to basically ignore the large ships -- the only ones transmitting an AIS signal -- and concentrate on smaller vessels, buoys, flotsam and jetsam, and sailing your boat. No need to know the names and particulars of the ships passing by. No need to call them on the radio. Just stay the heck out of their way, sail your boat, and pay attention to your own navigation. :)

Now, as entertainment for the off-watch crew AIS offers some real possibilities -- even competes with the DVD movie player!

Bill
 
#22 · (Edited)
...There's plenty of room outside the ship's channel for a small vessel to navigate without fear of being hit by a ship...
No, not always:

...AIS? Not so much. The ships all follow the ships channel. The channel is very narrow and is very well marked. There's plenty of room outside the ship's channel for a small vessel to navigate without fear of being hit by a ship. Using this strategy allows you to basically ignore the large ships -- the only ones transmitting an AIS signal -- and concentrate on smaller vessels, buoys, flotsam and jetsam, and sailing your boat. No need to know the names and particulars of the ships passing by. No need to call them on the radio. Just stay the heck out of their way, sail your boat, and pay attention to your own navigation. :)
Suggesting that someone sailing on a river never enter or cross the channel is like suggesting that someone walking in a city never cross the street. It just isn't reasonable.

It's a funny thing about channels - they tend to go down the middle of the river! So what's left is 1/3-1/2 the width of the river or less. That sliver of water may be OK on a reach or run, but can be dangerously narrow for tacking. And the fact is, most of the time there is no large traffic around, so you can safely cross the channel and use the whole river for tacking.

And even if you stay out of the channel, there are bulkheads and anchorages along much of the river, so the large vessels leave the channel more often than you may realize.

I typically sail about 2 mi downriver from one of those anchorages. With AIS I can tell at a glance whether those vessels are stationary (safe to enter the channel) or starting to move (stay out of the way). I don't need to call them, or look up their name, or pull up any menu for detailed information. I just look to see if there's a 5-minute vector in front of them, and I immediately know how fast they're moving. And since it's all overlaid on a chartplotter screen, it doesn't take any more attention than I'm already paying to the chartplotter (which I need to do if I'm staying out of the channel near shore).

Let's make a deal. I won't make you use that AIS that you like "not so much," and you won't tell me that I should ignore those big ships that come along every couple of hours.

 
#24 ·
My experience has been that getting a ship to answer a radio call has long been an issue, particularly with crews for whom English is a second or third language. As AIS has been more prevalent getting an answer from "Northbound tanker near bouy 74" is more and more difficult.

The most significant benefit of AIS to me is being able to call a ship by name. The response rate to calls by name is very high.

Certainly looking beyond the toe rail and using radar are key parts of maintaining situational awareness. AIS helps take the stress out of making contact and agreeing a course of action. I like communication.
 
#27 ·
I think AIS is a fantastic capabililty to have. Sure, it's not radar. But it's a lot less expensive and much easier to install. In fact, anyone thinking of upgrading their old non-DSC VHF radio should seriously consider spending a little extra to get a radio that also has integrated AIS receiver. (Or, even go for a full-fledged transceiver.) Be sure to register your MMSI, and while you're installing it also be sure to feed your chartplotter to the VHF so you can issue automated distress calls that have your GPS coordinates.

If you don't have a chartplotter, you should spend the extra $30-60 to get a puck style GPS antenna with NMEA output and feed that to the radio to fully enable your DSC. (I recommend this for ANY DSC radio, even those without AIS.) I found the Garmin 18x LVC for about $60 on Amazon - there are cheaper no-name brands available.

Despite what the naysayers say, AIS is very cool, and when used properly within its limitations, can be a very beneficial safety enhancement.
 
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