Is AIS in the house?

El and Bill · Posted: Wed Oct 29, 2008 4:45 pm Post subject:

Richard -
When we cruised the Black Warrior we used the VHF to identify our location and direction of movement and found that the tow boats were doing the same. El had great conversations with tow skippers (they suggested safe anchorages) and one skipper even told El of a dock where we could stop and get a cup of coffee from his Mom. So, for us, El was our best safety feature on the tight and curving sections of the river.

thataway · Posted: Wed Oct 29, 2008 10:23 pm Post subject:

Congratulations Tim on being the first C Dory with A I S "B" Transciever! The class was finally FCC approved Sept 20th 2008, and then the various transpcievers had to be certified. Great job!

How did you work around the "Official: The entry of static data into a Class B AIS device shall be performed by the vendor of the device or by an appropriately qualified person in the business of installing marine communications equipment on board vessels. In no event shall the entry of static data into a Class B AIS device be performed by the user of the device or the licensee of a ship station using the device."

I assume that you have the input to the RayMarine chart plotter--did it seem to clutter up as far as naviation?

Also, I notice that you used a splitter, and AM/FM antenna/ VHF antenna--would you expect better output (ie being seen on the Vessel Transit system) if you used a dedicated antenna--especially one with resonance on the Class B transmission frequency (AIS 1 = 161.975 mhz AIS 2 = 162.025 mhz; the top of the VHF marine band is at 157.425 mhz)? The 162 mhz frequency is enough out of the VHF band to have a potentially high VSR, and thus decrease the transmission effeciency.

Why did you choose this perticular transciever?

Thanks for the great write up.

timflan · Posted: Thu Oct 30, 2008 1:59 pm Post subject:

thataway · Posted: Thu Oct 30, 2008 7:27 pm Post subject:

With an increase of SWR, it will degrade the transmission--and many VHF radios have protection for the finals, so that power is decreased with a high SWR--not sure if this applies to the unit which you have. For reception--any wire seems to do fairly well--sure you will do slightly better with a frequency specific. I suspect that the difference may be more noticiable on reception of another class B unit.

As for the Gill netters--sure wish that there would be a way that they all had AIS, and it would indicate which side their net was set... In some areas, especially around Prince Rupert, in low visability, the gill nets were a real problem, since they were almost solidly set next to each other.

Good on the service for programing.

What data can you see on the RayMarine?--or is it just the vessel icom? Can you get course, speed, rudder angle etc as well as name?

timflan · Posted: Fri Oct 31, 2008 12:44 am Post subject:

Lots of information is available...

It's just a few clicks away. Sometimes, "a few clicks" are difficult to execute, depending on what else I'm trying to keep track of!

Thanks for the comments on antenna issues. I REALLY need to find another Class B-equipped boat to do some testing with!

thataway · Posted: Fri Oct 31, 2008 5:22 pm Post subject:

Thanks, Tim,
This was what I was interested in. I suspect I may go with the Sitex, which has a separate plotter--and that way I don't obscure the screen--I had seen some photos which showed the information on the side of the display.

The United States has been behind in allowing the Class B units, but I do see it as one of the greatest safety features which we have seen in many years. Of course it is no better than the person who is using the data.

Again, thanks for taking the lead.

Dene · Posted: Fri Oct 31, 2008 11:00 pm Post subject:

Very interesting thread. I sure can see how useful this would be on the Columbia River.

Is the day coming when active AIS will be on the web, available to all who subscribe?

-Greg

timflan · Posted: Fri Oct 31, 2008 11:26 pm Post subject:

Actually, there are several AIS-on-the-web services. My current favorite is MarineTraffic.com, which I wrote about on Navagear.

Dene · Posted: Sat Nov 01, 2008 1:24 am Post subject:

Grumpy · Posted: Sat Nov 01, 2008 8:39 am Post subject:

Sometimes quite interesting to run one or two of the web AIS sites side by side. They do not always say the same thing.
I can only surmise that they are getting their data from slightly different sources and also processing the reeived data differently.

Fascinating nonetheless to check against what you can see with the naked eye.

We hope to be up and running on AISB soon and will see if we can collide with Tim Shocked

Merv

marvin4239 · Posted: Sat Nov 01, 2008 2:19 pm Post subject:

There's some fascinating information here. The first thing that came to my mind was my granddad in his later years use to keep a log book of cruising boats going North and South on the ICW. This was 50+ years ago. He was unable to get out and did this from our front porch overlooking the ICW in NC. With this system and a shore station would he ever have been in hog heaven.

Second thing that comes to mind is it seems if you had a system that broadcasts your position you could track you vessel in the event it was stolen?

thataway · Posted: Sat Nov 01, 2008 7:06 pm Post subject:

Marvin, Interesting thought: using AIS as Lojac...Of course you have to turn the system on--or have it turned on, when the boat was started (could be technically easy to do). But then you would need to know the general area that the boat was in, since the VHF radio transmission (on 162 mhz) could be recieved. There could be a national database reporting system, which might be on the look out for stolen boats....but again, I suspect that the smart thiefs would disable the AIS.

There are several security systems which do currently track boats with GPS if they are stolen. These rely either on satellite or telephone communications.

hardee · Posted: Sat Nov 01, 2008 7:14 pm Post subject:

Tim,

timflan · Posted: Sat Nov 01, 2008 10:59 pm Post subject:

Grumpy · Posted: Sun Nov 02, 2008 9:05 am Post subject:

Tim,
If you go to one of the AIS channels on the web (not the Greek one) you can pan up to Vancouver BC and find one or two Class B targets. They way they have processed the data it seems to provide essentially the same information as Class A.

I hope to get the Nauticast system installed in next few days so when I get back from European trip we can compare notes and share with the "gang"

Merv