AIS Class B Transceiver Install

One of the systems we wished we had when we brought the boat down the coast from Seattle to Portland was an AIS transceiver.  AIS is an identification system that lets you identify and locate other vessels that are equipped with AIS. The International Maritime Organization's (IMO) requires ships of 300 or more tons and passenger ships to have AIS. We would like to see and be seen by large ships.  AIS receivers let you see other ships, whereas AIS transceivers let you see other ships as well as transmit your position, speed and heading to other ships, adding another layer of safety.

AIS uses Very High Frequency (VHF) and Global Positioning System (GPS) technology to gather and transmit AIS information to either a dedicated display, or it can overlay AIS information onto an existing chart plotter or navigation software such as MaxSea or Rose Point. Our Furuno chart plotter and radar are older and cannot decipher AIS, so we thought about upgrading our chartplotter. Unfortunately a new chart plotter and repeater at the nav station would end up costing more than $10k, so we decided to leave the Furuno chart plotter and repeater in place.  We can still use the Furuno for our radar display and GPS data display.  We will now use computer charts and overlay AIS information onto the laptop chart. 

 After some research, I chose the Comnav MarinerX2 Class B AIS transceiver, partly because it doesn't come with a VHF antenna. I didn't need a VHF antenna because I chose to use a splitter and use the same antenna for AIS and VHF, which is allowed. Plus it saves me a trip up the mast, which is not my most favorite thing to do. The splitter has a PL-259 plug for the antenna, and two plugs, one for the AIS and one for the VHF radio. That way, the VHF and the AIS share the VHF antenna. The splitter also has a FM connection, but I won't be using it since my radio antenna seems to be connected to something already.

 It was a bit of a mental exercise trying to figure out where to mount the AIS and the splitter since the nav station area is at a premium for real estate. I found a little spot for the splitter near the VHF radio, since the antenna cable already routes to that area and it's a short run from the splitter back to the VHF radio. The AIS is a little bigger than the splitter, but luckily, it has a low profile, so I mounted it under the nav station desk. It's not in the way at all, and we can easily reach under the desk and press the "silent" button to stop AIS transmission in pirate alley – if in the area.

 Instead of mounting the GPS antenna permanently and running the cable through a through-hull cable connection, I ran the RG-58 cable through a ventilation clamshell. This allowed me to test if the GPS placement will work in the current location, without having to drill a hole.  I’m going to be running some other cables through the deck (future project) and I may wait to see if I can bundle it and some other cables together in the same through-hull.

 The AIS has a NEMA0183 interface and a serial connection. I used the serial connection with a serial-to-USB cable and connected up to an old USB hub under the nav station. I won’t have to run individual USB cables to the laptop, I can just connect devices ( PACTOR modem) up to the hub and then we only have one cable from the hub to the laptop.

 For the power connections to the AIS and splitter, I used the chartplotter and radar circuit breaker. This way, we only have to flip one switch and we’ll have AIS, radar, and chartplotter all powered on. This is nice, especially since we are running out of space on our nav station for additional power switches. We currently have one slot left and we are saving it for the hot tub : )

 After the AIS was all wired up and powered on, we went to http://www.marinetraffic.com and looked for Bliss in the marina, but even after a while, we didn’t see anything. I thought there may be a delay on how long the data is displayed on the web site, so I called up the local Coast Guard station and asked if I was visible on AIS. The watchstander asked for vessel name and MMSI number and told me that I was not visible on AIS. The AIS interface showed GPS satellites in range and the AIS unit up and running, so I thought I maybe didn't connect the VHF correctly. I decided to swap the PL-259 cables one for the other. The one for the VHF to the AIS and vice versa. I powered everything back up and within minutes we could see Bliss on marinetraffic.com. The Coast Guard watchstander had offered to help if we needed another AIS check.  I called up the station again and this time he could see Bliss on AIS.