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Old 29-08-2013, 06:47   #1
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AIS: A Creepy Experience.

AIS: A Creepy experience.

I just finished my first cruising season with an AIS receiver, and have concluded.... the system is rather creepy in that it presents new potential and very real security risks, and is nearly 50% unreliable in detecting other vessels who choose not to transmit a signal.

In June, we installed a VHF radio which has the capacity to receive AIS transmissions, so along with a small Garmin chartplotter we began receiving AIS information... assuming that if we liked the setup, we'd upgrade next season to a transponder to receive and send AIS.

We've decided not to improve our current set up and will continue to only receive information.

Our reasons: AIS is creepy and unreliable. We found that many large ships including cargo ships, tankers and superyachts (over 200ft) don't always transmit their position or activity for whatever reason.... maybe security, privacy, taxes.... who knows? But on at least three occasions we found ourselves having to alter our course for a container ship and two superyachts who were not transmitting and were on a collision course with us during the day here in the Med.. Also, more than 50% of all pleasure craft and fishing boats do not transmit a signal. Fishing boats, possibly to not alert others as to where to find the fish.

And now here's the creepy part... One day, we left port where some folks we'd met the night before remained for an extra day... we didn't know their itinerary. Two days out, my wife noticed their AIS transmission (via boat name) on our plotter as the vessel two miles ahead of us, so it remained near the top of the list the entire day. Each time I went below to check other things, I couldn't help but notice what our friends were up to... their movements, speed, location within 15 feet, vessel type and size. I knew when they were underway, when they were in the marina looking for a berth and when and where they had decided to anchor instead. It just so happened, that we had planned several days earlier to anchor in the very same cove which they had also chosen. We weren't trying to follow them, but after seeing how easy it would be for the wrong people to do the same, we decided not to improve our system with a transponder and shared the experience with our new friends.

We'd all like to assume that all the people we meet have only good intentions, well.... my wife and I know otherwise from past experiences and robberies. When you transmit AIS, just remember that for about $500 the wrong people can also see exaclty where you are at all times from a boat.... or from anywhere in the world via the internet.

Would you even consider transmitting AIS in your land-based life?

'Just a thought.
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Old 29-08-2013, 06:52   #2
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Re: AIS: A Creepy Experience.

You make a good point, but if you have a celphone, what you describe is 'AIS land-based transmission,' as it were. There is no such thing as real privacy anymore...
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Old 29-08-2013, 06:55   #3
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Re: AIS: A Creepy Experience.

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Originally Posted by tamicatana View Post
You make a good point, but if you have a celphone, what you describe is 'AIS land-based transmission,' as it were. There is no such thing as real privacy anymore...
Definitely a possible liability anywhere in the Indian Ocean between S.E. Asia, India and South Africa. Especially considering pirates have mined the internet looking for blogs revealing a boat's itinerary.
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Old 29-08-2013, 06:59   #4
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Re: AIS: A Creepy Experience.

I share all your concerns about AIS. As currently implemented I don't see it as a completely reliable way to identify potential collision risks and in fact brings a risk for an unsophisticated user to rely too much on the AIS data and possibly miss seeing a risk that isn't tracked.

Maybe I'm the unsophisticated one, but I never had any problem not running into ships at sea and I have been in some pretty busy shipping lanes.

Your point about putting your location out for all to see is also a concern. Crossing the English Channel or cruising up the south FL coast I wouldn't be worried but many areas, if I had one, it would not be transmitting.
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Old 29-08-2013, 07:16   #5
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Re: AIS: A Creepy Experience.

AIS is a great tool in your electronics and manual arsenal. It allows you to very quickly determine CPA and TCPA of transmitting ships. This covers the vast majority of large ships -- any ship over 300 tons that travels internationally, excepting military, is required to use it. If you don't want to transmit your position, don't. I have my AIS TX on when we are on passage or in reduced visibility, otherwise I usually leave it off.
Its just a tool, and clearly not a 100% - like all other nav tools.
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Old 29-08-2013, 07:22   #6
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Re: AIS: A Creepy Experience.

You sound paranoid
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Old 29-08-2013, 07:36   #7
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Re: AIS: A Creepy Experience.

"....[AIS] is nearly 50% unreliable in detecting other vessels who choose not to transmit a signal.is nearly 50% unreliable in detecting other vessels who choose not to transmit a signal." --Kenomac

Purely to set the record straight, I'd suggest that one's AIS cannot detect a vessel that is not transmitting an AIS signal. AIS was never meant to be a substitute for maintaining a vigilant watch. Some vessels don't show; nor do wooden ones on radar. They are still useful tools.

I think the security issue may be a valid one, especially for flashy, large vessels that would in any case be obvious targets. Perhaps those who are concerned with those issues would be best advised to pursue their security interests in a circumspect manner....and not bruit them about on the gossipy internet.

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Old 29-08-2013, 07:37   #8
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Re: AIS: A Creepy Experience.

It is not paranoid, you are broadcasting your vessel information for all to see, only the intent of the individual seeing the information differentiates between good and bad results. If you are that worried about collisions at sea, why not purchase an ARPA equipped radar? Far more useful in my book.
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Old 29-08-2013, 07:39   #9
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Re: AIS: A Creepy Experience.

I used a transponder for a couple of years, and noticed that I never got chosen by the coast guard for a safety inspection during that time. May be one of the upsides of the transponders is that big brother is happier knowing where your are and have been.
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Old 29-08-2013, 07:43   #10
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Re: AIS: A Creepy Experience.

Ah, c'mon, AIS is nothing compared to a real stuff - they are not only following you, but they are frying your brains from satellites! I know that, my doctor has confirmed that I am onto a real thing! I am using a tinfoil hat and I recommend anyone concerned about their privacy, to do the same. As well, turning off navlights, and in general getting rid of any electicity onboard may be a good way to improve privacy, because the BAD GUYS are out there, watching, tracking you on their computers, and are only waiting to do BAD things to you! The world is a dangerous place and we are prey!
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Old 29-08-2013, 08:17   #11
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Re: AIS: A Creepy Experience.

If it bothers you to transmit your signal turn it off. Simple as that. In the current waters I cruise in I have no security concerns that some nefarious persons my try and use it to find my boat for whatever reason. Maybe you might just fire up the transmitter when you see a ship on your receiver so they get a heads up you are out there and not leave it on all the time. To me an AIS transponder is another great tool to have on board. How you want to use it is entirely up to you.
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Old 29-08-2013, 08:18   #12
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Re: AIS: A Creepy Experience.

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Originally Posted by Kenomac View Post
50% unreliable in detecting other vessels who choose not to transmit a signal.
Mine is 100% unreliable at detecting vessels who choose not to transmit a signal.

I even never saw a dinghy without batteries nor electronics never transmit an AIS signal. So I am SURE mine is unreliable and I threw it overboard!

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Old 29-08-2013, 08:23   #13
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Re: AIS: A Creepy Experience.

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Originally Posted by captain58sailin View Post
If you are that worried about collisions at sea, why not purchase an ARPA equipped radar? Far more useful in my book.
I agree. We use our radar as a secondary collision avoidance tool. Primary of course is one of us keeping watch. Receiving AIS is just one more tool.

Note: It's necessary to use radar often and not just when it's dark or foggy as some do. Very important to learn how to interpret what you see on the screen with lots of practice.
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Old 29-08-2013, 08:31   #14
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Re: AIS: A Creepy Experience.

"nearly 50% unreliable in detecting other vessels who choose not to transmit a signal." Kenomac


This is what happens when I don't wear my reading glasses and decide to edit a previously coherent sentence. Should have read "detecting other vessels (period)." Oops.
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Old 29-08-2013, 08:31   #15
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Re: AIS: A Creepy Experience.

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Originally Posted by Kenomac View Post
I agree. We use our radar as a secondary collision avoidance tool. Primary of course is one of us keeping watch. Receiving AIS is just one more tool.

Note: It's necessary to use radar often and not just when it's dark or foggy as some do. Very important to learn how to interpret what you see on the screen with lots of practice.
Not concerned about the $200 Radar detector letting the bad guys know you are there?
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