AIS

[chase]

Followed last thread about AIS, but don't quite understand how it operates. Does it require a laptop to operate? Can you use it with a wide range of chartplotters? I remember Russell saying he used his with the E80 I think.

As I understand it, you can transmit and receive ship data wit hthe transmission function being a real safety benefit when paired with proper watchkeeping.

Chase

[Russell]

Followed last thread about AIS, but don't quite understand how it operates. Does it require a laptop to operate? Can you use it with a wide range of chartplotters? I remember Russell saying he used his with the E80 I think.

As I understand it, you can transmit and receive ship data wit hthe transmission function being a real safety benefit when paired with proper watchkeeping.

Chase

Most current chartplotters should support displaying AIS data via NMEA input. The manufacturers website should verify this. If your plotter is more then 1 or 2 years old it may need a software update to do so though.

A laptop is not nessisary for operation. On a transponder you may need one for initial programming, but that is a one time thing. For a receive only AIS it is entirely unnessisary.

[Russell]

Here are a couple short articles I wrote for All At Sea a couple years ago that explain AIS. They are a little out of date but still convey the principal behind AIS. The origonal print articles had some nice screen shots that unfortunately are not in the online version.

http://www.allatsea.net/specificissueed ... ureid=1037
http://www.allatsea.net/specificissueed ... ureid=1071

I am happy to explain more about AIS or clarify anything not understood, I honestly think this is the best thing to come along since GPS.

[ocean31]

I agree most strongly with Russel, the two things that have revolutionized watch keeping on smaller commercial vessels, is the GPS and AIS. Looking back it is hard to comprehend how we worked without them.

For what it is worth, the most common AIS unit out there on small commercial vessels is the Furno model. I do not know the model number, and by now there is probably newer models available. But the Furno and most other models only have a serial port output. You need a to hand make a cable with male and female serial ports, then use a serial port to USB adapter. The serial port cable is handmade since only a few wires are used, and certain wires hook up to certain pins on one end, and certain pins on the other end. Sound more complicated then it is in reality. When I did mine for use at work, I just ran down to Radio shack, got a couple cheap no solder Serial ports and some quadplex light guage wire. I then have my cable along with the USB/serial adapter in my laptop bag. When I go on a vessel without a laptop it is a couple minutes work to set up. With the technical savvy and ability of our forum members, I have no doubt someone can explain better a simple way to set up a AIS to laptop connection.

I will say that if you choose to use AIS, try your best to set up one with a transmitter/transponder. It makes all the difference when dealing with commercial vessels.

Ocean31

[Andy Denmark]

Hey Chase,

If you want to see an installed AIS In Real Life there's one that's been installed this week on a Valiant 42 at Whittaker Creek Marina. The owner will be glad to show/demonstrate it to you.

Besides, Anne Freeman is missing you and this will be a good excuse to get away from the chores!

Andy
________
GRAPE APE MARIJUANA STRAIN

[CruiseAlong]

I installed a Millitech Marine SR161 AIS (receiver only) on my CD26 a couple of years ago. At that time it was ~$169 and could monitor both ship frequencies but in serial time. It does, however, do a very good job with a reception range of about 25 miles here on the lower Chesapeake Bay. I decided to use the same antenna as my VHF so I purchased the automatic antenna switch (~$80) which electronically disconnects the AIS receiver when I key in a transmission on the radio. The receiver is small and mounts behind my VHF. One red LED on the receiver tells you are ON and recieving transmission. Another green LED flashing tells you it is AIS information. A NMEA 183 serial cable is all that is needed to connect to the PC serial port or serial input port of a chartplotter. The PC nav or Chartplotter (if capable of showing AIS) usually graphically shows the target vessels) and their headings. If you put your cursor next to the target there is usually a menu which pops up showing information about the vessel. This is normally Ship name, heading, speed, destination, beam, draft, length, current operating mode (underway, at anchor, etc.) Some of this information must be manually entered by the ship which sometimes they don't. Some features of the chartplotters or PC programs have collision avoidance features. One sets how close you are willing to come when intersecting with the ships course and how far away. Alarms go off if those conditions are calculated to happen based on your boat and the ships heading, speed, etc. Having the Ships name displayed is great if you have to go Bridge to Bridge communication to clarify course intentions. The serial port communication speed is generally a standard (38 Kbaud) unlike the slower speed of earlier GPS. The SR161 is nice that one can input a GPS signal into the AIS receiver and it will be combined with the AIS NMEA information and outputed to the PC or chartplotter as a single signal. Sail magazine had a nice article on these new AIS and DSC radios about a year ago. To see a simple example google search with "AIS Galveston Bay" and button on one of the ship "pins" in the harbor.
Dana

[Kittiwake]

After sailing together from Port Royal Sounds to St Mary's River with another boat that had AIS receiver - I've been giving it a lot of thought. The MillTech Marine website: http://www.milltechmarine.com/products.htm has the best discussion of it that I've found, and various brands of receivers, and receiver/transmitters. I have a 5 yr old Raymarine C series chartplotter with software updated late last summer. Now it shows that no AIS is available, so think that it's set up. The various products on the MillTech site have pretty good info on what chartplotters they will hook up to, but they have to be fairly new.