OK, I'm not gonna leave this alone. As I mentioned above, for less that $200, cheaper than a Generac generator, I've added AIS to the boat. Antenna and all. And why am I so pumped?
Well, we spend a lot of time dodging the Washington and BC ferries up north and down south the Chinese container ships cruising at 25 knts between Santa Cruz Island and the mainland. You hit one of those babies and your day is over. Don't forget the tankers and container ships going through Rosario Strait and Boundary Pass or the Catalina Channel or up and down San Francisco Bay. So anything that helps is gonna be good, and AIS helps. You do not need a transmitter, just a receiver. Nothing against a transmitter, but those cost a great deal of money and don't give YOU more information.
What does AIS do? Well, by law, all those biggies have to broadcast thier ID, position and velocity via AIS transmitters. So that data is out there for free. And when you receive it, and plug it into your navigation program you get:
... The name and type of vessel, so you know at which one you're looking.
... And that name shows up at the ships position, reaffirming your view.
... Also, most nav programs accept AIS data and calculate:
...... Closest point of approach based on your GPS data and their AIS signal.
...... The time of that closest point of approach, so you can decide with some accuracy if you're going to have to duck or just keep on going.
... It also displays their speed and direction.
Now, this supposes you're running a navigation program that accepts AIS data, either on a PC or a chart plotter. I think all the newer ones do: Fuguwa, Rosepoint, Mapquest as well as Furuno, Raymarine, Garmin, etc. And a large number of C-Brats have one or the other.
So how easy was the Nauticast receiver to interface? Easy, once I went to a place that had AIS signals, as in San Diego Harbour. First you have two choices for input into your PC or chartplotter: USB or dedicated RS422 lines. And you can multiplex your GPS data through this AIS receiver, or use an independent input. The input comes via NMEA sentences, and the unit only outputs data when it receives an AIS signal , which explains why I had to leave the mountains and go to San Diego. It needs its own DC supply, but it only takes 200 mw. The Fugawa software picked up about 20 signals and plotted them on the chart and showed a table of the ships and the data. Most were docked.
So, I heartily recommend the ACR Nauticast AIS receiver as a low cost nav aid with a large payoff.
Boris