VHF Radios with AIS

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VHF Radios with AIS

Postby raymacke » Sat Aug 15, 2015 7:59 am

If you are in the market for a VHF radio and cruise where there is any commercial vessel traffic you may want to consider one with AIS capability. Just added this to the True Grit and have to say I am impressed. If you are not familiar with AIS it is very similar in function to the system used in air traffic control. Most all commercial vessels are required to have an AIS “transmitter” and many larger pleasure are adding it too. In real time it sends out a signal containing information about the boat. Location, course and speed are broadcast as well as the name of the boat and other information. Google "Marine AIS" for lots more info.

If you have an AIS receiver (many new VHF radios have the ability) you can see this information. Usually the radio itself can display the information on it's screen. It also compares your location and does calculations and shows how close you will come to the other boat and how long until you are at the closest point. But it becomes even more useful if you connect it to your GPS/chartplotter. If you do that an icon will appear on the plotters screen showing the boats location and can then display the information. The range is usually 10+ miles.

Why do I like this? Besides the obvious there are a few things I have learned while cruising. Often I find myself in a narrow channel with a large tow/barge vessel. I need to pass on one side or the other but which? The normal procedure is to hail them on the radio and ask their preference. But I don’t know their ship’s name. And maybe there are two other tows nearby. How do I call and make it clear which one I want to talk to? AIS solves that problem. You can look at the screen and see their name. But even better than that you can press a button and it will use the built-in DSC capability (another feature) to “call” them directly and have a private conversation. No question about getting the right boat.

Also, several times I have found myself on a narrow winding river and pop around a tight corner to be “surprised” by a tow looking right at me - Pucker Factor skyrockets! But with AIS I will be able to see them coming miles away on the plotter screen. I can then call the ship and get instructions long before I can even see it. Now that is impressive!

A full duplex AIS system both transmits and receives data. This is what is required on commercial vessels. I looked in to this but the price falls between $600 and $1000 by the time you get done (cost of VHF radio and AIS unit and needed parts). But you can buy a simplex system (receive only) that allows you to see the other ships but it doesn’t transmit your information for them to see. This is what you are getting built-in to the VHF radios and is what I bought. A basic VHF unit runs about $100 to $120. A VHF unit with AIS runs about a $100 more which is reasonable in my opinion.

The first photo below is what it looks like on my Lowrance plotter's screen - a triangle with a line showing the direction of travel. If it is not moving there will be no line. The way it displays may vary with brand. If I touch the triangle the name of the boat pops on the screen (my plotter is a touch screen). If I then touch the name the next page comes up.

The second photo is the page with the information. The day I took these photos of my screen I was on the Kaskaskia River eight miles from the confluence with the Mississippi. Yet I could "see" six commercial tows working on the Mississippi moving in various directions. The Sullivan below was one of these. Since he was moving away the CPA (Closest Point of Approach) and TCPA (Time to Closest Point of Approach) is not showing. Here is a link that will explain these - http://digitalyacht.net/2014/04/03/cpa-and-tcpa-alarms-explained/
Screen (Small).jpg
Info (Small).jpg
So Many Rivers,
So Little Time....

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Re: VHF Radios with AIS

Postby kens » Sat Aug 15, 2015 7:18 pm

I thought almost all VHF's have that feature now.
I have it on my cheap VHF, but I don't have it slaved into chart plotter , nor can I see other traffic.
I think mine is a mayday sending feature only.
No, I don't have 'touchscreen' chart plotter, either!!!!
What next Ray,? You gonna get the remote controlled autopilot that allows you to dock the boat 'from the dock'??? :lol: :D :lol: :D
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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