I installed an em-Trak 953 last season and agree AIS is an invaluable
safety tool. It allows me to see traffic 20+ miles away. Last season I radio'd a ship several miles away. She told me she saw me awhile ago, had already altered course to give us more room and was monitoring our course.
Another advantage is you're visible on MarineTraffic and other ship
tracking apps/web sites. Friends and
family can see where I am (might be a big disadvantage to some!
). This only works when in range of the service's terrestrial receivers. See
images for examples.
As someone else said, the AIS is also a second GPS device on my
NMEA 2000 network. I also connected mine to the nav station
chartplotter via
NMEA 0183 for redundancy in case something happens to the
NMEA 2000 network.
I went with the integrated antenna splitter and is the newer SOTDMA technology which brought the price closer to $670. I opted for an external GPS antenna ($40) for faster GPS lock because of my mounting location sideways under a
wood shelf. It is still inside the
cabin and would not be needed if I mounted the unit in a different location.
I purchased mine from Milltech
Marine (
https://www.milltechmarine.com/) and found their service outstanding and prices very competitive.
Regarding plug and play, mine truly was plug and play to get AIS information! I did have to change a config setting (very easy) to make GPS data available via
NMEA.