Automatic Identification System (AIS)

[Fred and Margaret Keith]

I just added an AIS transceiver on my 45' sailboat. I have not taken my boat from the dock yet, but from there I can pick up signals from large vessels as much as 14 miles away. I would like to hear from other pleasure craft that have, or are contemplating, installing the device.

[h]

Fred,

I have also installed the AIS transponder.

What feature I like for the AIS is a guard zone. I am not sure that my chart plotter has that feature. I will write to Garmin so they can improve their software on the smaller Garmin 540S.

Howard

[Fred and Margaret Keith]

My AIS is compatible with my Raymarine C80 chart plotter so the targets are overlaid on the chart, just like the radar. I have a guard zone feature on my radar, and usually set a circle about 3 miles radius. I have not gotten a good measure of my AIS transmit distance, but I have had a response from a vessel 3 miles away saying he could see me on his chart.
We are leaving this Wednesday, February 4, for 2 months or so in the keys and perhaps the Bahamas. Our first leg is from Panama City, Florida to Clearwater, Florida - about 225 miles of open Gulf of Mexico. We were going to set out today, Sunday, February 1, but the wind predictions were for 30 knows from the NW and that would have given us a large following sea. I would have loved it, but my wife does not do large following seas!

[Fred and Margaret Keith]

Bill, I see you are from Marathon. We were there last March and spent a couple of days at the Marathon Yacht Club. Since we draw six feet on our 45' sailboat we drug the bottom from the Intracoastal on the northern side of Marathon down to the club - seems like it was about one mile. Our cast iron keel was sandblasted a little.
We leave here (Panama City, Florida) this Wednesday, February 4, and will make our way down the west coast stopping at a few of the yacht clubs to rest, and then after visiting Dry Tortugas and Key West we are going to make our way to Boot Key Harbor and moor there for a while. We have friends from Indiana there now. Maybe we can touch base with you. I would like to hear about the CARD.

[Fred and Margaret Keith]

I keep my boat at a private dock in Parker Bayou on St. Andrew Bay - about 5 miles from the Naval Coastal Systems Station - which you may be familiar with considering your work.

It will probably be a couple of weeks before we arrive at Marathon. We will spend about a week going down the west coast and to The Dry Tortugas. I really enjoy it there so we will stay a few days at least. Probably stop three times on the way to Marathon - Maquessas, Key West, Bahia Honda - so it may be two weeks or more.

[Veranda]

We have been using AIS for about a year now. Definitely one of my favorite upgrades to the boat. Our radar only has a 16 mile screen and since AIS info is gathered via the VHF our range is whatever propagation allows. We routinely "see" boats at 20 to 25 miles away. We've had "skips" on the ocean where we've watched in horror as a ship 80 miles away was bearing down on us. :) Having 8 or 9 hours to begin evasive maneuvers makes life much easier. :)

AIS can also see who coming out of an inlet while the radar is blocked by the shoreline. It displays very nicely on our chartplotter. We love it.

AIS takes a lot of the tension out of crossing situations. A perfect example of the value of AIS occurred while we were northbound off Savannah, Ga. There were several boats (freighters and such) moored offshore waiting for their turn to enter the port. The pilot boat was running in and out and there was a steady stream of traffic in and outbound and of course it was pitch dark. Our course was 0 degrees and a large tanker was going to cross our bow on a heading of 090 degrees. I figured his CPA would be about 3 miles off our bow, no problem. Then he made a subtle course change. He came 10 degrees to starboard to a heading of 100 degrees. This changed our CPA with him crossing our bow at a quarter of a mile away. Too close.

I called him by name and told him he had just altered course towards our vessel. Then I asked if he was done maneuvering and would he be holding his present course and speed. He assured us he would be continuing on his new course. I informed him that we would be altering course 40 degrees to port and would be crossing his stern about a mile behind him.

I knew we had a comfortable crossing situation until he made that 10 degree turn towards us. The turn was so slight that we would never have seen the change with the naked eye, especially at night. If not for the AIS I wouldn't have had his name which prompted him to give us an immediate response to our call. We would have eventually seen the danger on the radar but with the AIS it was instantly apparent.

Bill
s/v Veranda

[Dave Skolnick]

I'm about to pull the trigger on purchase of an ACR Nauticast B transponder (it transmits AIS as well as receiving it). If it all works out I am likely to pick it up as an installer. I'm still working on the supply chain, but I hope I can give a SeaKnots discount. Stay tuned - it will still be pretty much a boat buck all in.

[Fred and Margaret Keith]

My AIS also broadcasts as well as receives. I bought it from West Marine primarily because it is easily configured to communicate with my C80 Raymarine Chartplotter. I can also monitor it with my laptop.
The unit came with its own GPS antenna, but my biggest problem was the requirment for a dedicated VHF antenna. Since a regular antenna splitter will not work properly, I considered buying a powered antenna signal splitter, but the ones I found on the internet specifically for use with an AIS were over $300.00. Since the AIS transceiver cost only $500.00, I could not see paying $300+ for a splitter. Not wanting to run another wire through my mast (the wire channel is full) I mounted the AIS antenna on my aft pulpit (pushpit to some purists). I may at some point put it on a post to get it higher, but for now it seems to work satisfactorily. I routinely get signals from 14 miles.

[Veranda]

Millitech Marine sells an automatic splitter. I got mine about a year ago for about 120 dollars. Its worked seamlessly since installation.

Bill
s/v Veranda