AIS is very Cool

treilley · #1 (**permalink**) 10-21-2011

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#

btrayfors · #2 (**permalink**) 10-21-2011

Quote:

Originally Posted by treilley

...... 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

Maine Sail · #3 (**permalink**) 10-21-2011

Quote:

Originally Posted by btrayfors

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

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..

treilley · #4 (**permalink**) 10-21-2011

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.

JonEisberg · #5 (**permalink**) 10-21-2011

Quote:

Originally Posted by treilley

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.

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)

CapnBilll · #6 (**permalink**) 10-21-2011

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.

btrayfors · #7 (**permalink**) 10-21-2011

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

treilley · #8 (**permalink**) 10-21-2011

Quote:

Originally Posted by JonEisberg

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...

Jon, we had it on 24/7 for 17 days. Our house bank is 510AH. We have 2 140w solar panels but also have 12v Frigoboat refrig. Although I have not yet done any specific power consumption studies, I did not notice a significant draw over what we are accustom to without it running.

jackdale · #9 (**permalink**) 10-21-2011

Quote:

Originally Posted by treilley

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.

One other thing for the record. DO NOT USE MARINETRAFFIC.COM IN PLACE OF A REAL AIS.

Quote:

Notices: Vessel positions may be up to one hour old or incomplete. Data is provided for informational reasons only and is not related by any means to the safety of navigation.

BTW - I like that you have a transponder. I often use a boat that only has a receiver. I am amazed at the number of times that my sailing vessels, with the correct nav lights, has been mistaken for a fishing boat.

One future problem for AIS is that as more vessels use it screens will become more cluttered. I think that a separate AIS screen will be necessary so that chartplotters and radar screens will still show crucial information.

treilley · #10 (**permalink**) 10-21-2011

Quote:

Originally Posted by jackdale

One other thing for the record. DO NOT USE MARINETRAFFIC.COM IN PLACE OF A REAL AIS.

Agreed. I guess I was trying to imply that with my statement.

Quote:

Originally Posted by jackdale

One future problem for AIS is that as more vessels use it screens will become more cluttered. I think that a separate AIS screen will be necessary so that chartplotters and radar screens will still show crucial information.

I also agree. It is very useful for me now that I am coastal cruising but I feel the real benefit is for off shore sailing which I plan to be doing in a few years.