AIS benefits

[Banshe]

G'day,

Before leaving Western Australia almost one year ago I purchased a AIS class B transponder. I had already purchased an AIS receiver only the year before, but within a week of buying the AIS receiver only I realized I'd made a huge mistake. You don't so much want to see other ships, as you want them to see you! The transponder does both.

AIS would have to be one of the biggest breakthroughs for marine safety since the invention of radar seventy odd years ago. Land stations have popped up like mushrooms all over the world giving amazing coverage. Sometimes up to one hundred miles off shore. Signals are also relayed on from ship to ship so as long as they are within fifty odd miles of each-other. I have been able to see ships over four hundred miles at times in busy shipping lanes. And it's only going to get better.

While radar still has it's uses, very few watch-keepers aboard big ships monitor it continuously. They may glance at it now and again, but AIS they constantly monitor 24/7. In the 15,000 miles I've traveled this past year I would have had at least six occasions when the CPA (Closest Point of Approach) has been within a few meters of a ship heading my way. I am transmitting my course speed etc which they can see. But most importantly I'm transmitting SAILING VESSEL. On all these six occasions the ships, some 330 metres in length, have altered course at a distance of least two miles, and missed me by at least one mile. In respect I try to hold the straightest course possible.

It should be understood, that the ships are being monitored and tracked by land bases, and other shipping. Their track is being recorded 24/7. If there is a collision at sea, there is instant proof of who was the stand on vessel and who was not. This makes the Masters of these vessels very scrupulous and careful.

In summary: Anyone considering going more than a few miles offshore would be very wise to spend six hundred dollars plus and buy one and install it. To not have one in my opinion is foolishness and is placing unnecessary danger to themselves and an unfair burden on the Masters of large ships.

If you want to know where I am at the moment. Go to marinetraffic.com -vessels-all-Banshe.

James

[Jon Eisberg]

Originally Posted by Banshe

...You don't so much want to see other ships, as you want them to see you!

Yup, that definitely appears to be the prevailing wisdom, these days...

;-)

[Mike OReilly]

I installed a receiver-only and like it so far. It's been useful as we transit some pretty heavy commercial areas here on the Great Lakes/St. Lawrence Seaway. I view collision avoidance as my responsibility, and am sufficiently paranoid that I don't feel the desire to be transmitting my vessel's position to all and sundry. But transmit away! I'll be watching for you .

[Jenny D]

I agree 100%. For me it has taken all anxiety out of traffic situations. You know exactly how close another vessel is going to get, and if there's any doubt you know their name and can call them up. Everyone should have AIS!

[Pete7]

Originally Posted by Jenny D

Everyone should have AIS!

Perhaps, but if everyone transmitted in some of the worlds busiest parts then it becomes hopeless.

Perhaps traffic lights might be better

[Pete7]

And why do people have it transmitting when they are tied up in a marina? are they just showing off saying "we are on board?"

Pete

[Stu Jackson]

Originally Posted by Pete7

And why do people have it transmitting when they are tied up in a marina? are they just showing off saying "we are on board?"

Pete

Pete, I agree. IIRC, Evans started a thread some time ago suggesting that people turn them off when berthed. There was a pointed discussion about it, and someone or many may have mentioned that filters on the units could be employed. I forget the details. Anyone?

[Nicholson58]

Originally Posted by Mike OReilly

I installed a receiver-only and like it so far. It's been useful as we transit some pretty heavy commercial areas here on the Great Lakes/St. Lawrence Seaway. I view collision avoidance as my responsibility, and am sufficiently paranoid that I don't feel the desire to be transmitting my vessel's position to all and sundry. But transmit away! I'll be watching for you .

Mike,
We sail the same areas -based in Muskegon. On several transits to north Channel & Lake Superior, the MIB & Homeland leave you alone if you have a transponder. We were once approached at close quarters near False Detour passage. 900 HP & machine guns. Hailed by our names. Greetings were exchanged & have a nice trip - no boarding. If they know your boat and master's data there is probably no reason to hassle the vessel. In 7 years sailing, the various authorities have never bothered us. We also get a USCG AUX inspection & sticker annually before launch.
(Watchmate 850 AIS)

[Paul Elliott]

Originally Posted by Pete7

Perhaps, but if everyone transmitted in some of the worlds busiest parts then it becomes hopeless.

[image of a very busy AIS screen]

OK, I'll bite.

Honestly, I don't really understand this complaint. I've heard it a lot, but would you rather *not* see the other/smaller boats? Sure, you can just put your head up and look around, but isn't that already our primary collision-avoidance technique? So we then have our AIS screen as an additional aid, and I personally would like to see more boats transmit AIS, rather than fewer. I know not to rely on automatic alarm settings in crowded waters, and if a boat is out there I want to have every chance of seeing it.

Would you have the same objection to smaller boats carrying a radar reflector? They sure can clutter up the display!

[Stumble]

Originally Posted by Pete7

Perhaps, but if everyone transmitted in some of the worlds busiest parts then it becomes hopeless.

Perhaps traffic lights might be better

That's what, a couple thousand square miles of water displayed there? Just zoom in a bit and it gets better.

As with most things turning off your AIS while anchored depends. On the lower Mississippi ships keep it on by rule, since even at anchor they can be navigation hazards.

[zboss]

Originally Posted by Pete7

And why do people have it transmitting when they are tied up in a marina? are they just showing off saying "we are on board?"

Pete

I find that annoying as well but... My AIS is all in one with my NMEA. So when I power up my instruments because I am interested in wind, the water temp, or using the radar to watch that upcoming storm, the AIS goes on as well. I'm planning on installing a switch but as of yet I have not because I am waiting for that to be a Garmin software option instead.

The thing is... this is not a problem with transmitting. This is a receiving problem. Not sending data is not the solution as More data is always better.

Filtering the data at the receiving station is the solution.

AIS receivers need to be equipped with more advanced filtering solutions... for example, to filter out AIS targets that have not moved by X distance in Y time.

[DotDun]

Originally Posted by Mike OReilly

I installed a receiver-only and like it so far. It's been useful as we transit some pretty heavy commercial areas here on the Great Lakes/St. Lawrence Seaway. I view collision avoidance as my responsibility, and am sufficiently paranoid that I don't feel the desire to be transmitting my vessel's position to all and sundry. But transmit away! I'll be watching for you .

I turn off transmit when I deem it not necessary. Not because I don't want surrounding vessels to see me, but to thwart the Internet miscreants from watching my every move, cross referencing transmitted data with other publicly available information, etc.

I'm waiting for the ability to use psuedo-random MMSI numbers that can't be traced back to identifying data. After all, it's only used to hail you on the VHF. I hope IMO fixes this soon.

[Mike OReilly]

Originally Posted by Nicholson58

Mike,
We sail the same areas -based in Muskegon. On several transits to north Channel & Lake Superior, the MIB & Homeland leave you alone if you have a transponder. We were once approached at close quarters near False Detour passage. 900 HP & machine guns. Hailed by our names. Greetings were exchanged & have a nice trip - no boarding. If they know your boat and master's data there is probably no reason to hassle the vessel. In 7 years sailing, the various authorities have never bothered us. We also get a USCG AUX inspection & sticker annually before launch.
(Watchmate 850 AIS)

I suppose that's a good reason to transmit. Luckily our Canadian water cops seem less enamoured with randomly stopping boats without cause. In all my years of boating on the GL I've been "safety inspected" once.

I did have a close encounter with our MIB (RCMP and border service in a joint scary boat), but it turns out they only came over to inquire about our wind vane. The officer was a fellow sailer and just wanted to know how often we used the Aries. Too funny...


Why go fast, when you can go slow

[chouliha]

Banshe writes: In summary: Anyone considering going more than a few miles offshore would be very wise to spend six hundred dollars plus and buy one and install it. To not have one in my opinion is foolishness and is placing unnecessary danger to themselves and an unfair burden on the Masters of large ships.


I agree. Originally purchased a Watchmate 750 because the 850 was not USCG approved. We quickly upgraded to the 850 the next time we flew back to the U.S. I agree that watch keeping is up to us to avoid collisions and follow the rules of the road but have the large commercial vessels see you as well it's a no brainer for us.

For example: We were headed towards the Panama Canal from Ecuador. The last night out was raining with heavy squalls with wind on the nose. Still 100 miles out and it was looking like a long night with 45 active AIS targets showing up on the screen. We had vessels coming up from astern that as they got close would alter course to pass us with plenty of room. After the 6-7 vessel passed us in this manner I started to unwind a bit. Did we slack off our watch keeping? heck no but at least we were able to breath easier that we knew the big boys could see us and give us room. Now if we had AIS receive only it would have been much more stressful and we probably would have been on the radio a few times or more. Not once during this night did we have to pick up the VHF and make a call "Do you see us?".

For us especially night watches have been easier since we put the Watchmate 850 onboard.

Just my 2 cents worth....

Chuck
Jacaranda
Nuka Hiva, Marquesas



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[Rustic Charm]

Another AIS thread.

yep, I love it. Mine is built into the Standard Horizon VHF set. i'm probably going to upgrade to the Vesper 850 as I too think the 'be seen' is also my responsibility, which is why I have a radar deflector which does't seem to work very well.

As for the comment we wouldn't want every boat transponding? I find that odd. Of course we want every boat showing where it is. Safer that way.

And if you get the Vesper then all you have to do is set it to weed out the irrelevant targets and they all disappear.