I tweeted the above photo of my new setup, and it seemed to be quite popular, so i thought i would post an explanation of the setup.
All vessels over 350grt are required to transmit an ais signal (automatic identification system) over VHF. I have a 8′ VHF antenna mounted on my house connected to an SR-161 AIS receiver. The AIS receiver converts the VHF signal to an NMEA sentence. The NMEA sentence is sent to an old laptop running ShipPlotter which takes the NMEA data, logs it, displays it on screen, and sends the update to marinetraffic.com. (I operate station 347)
the 3 monitor setup is accomplished by running 3 instances of ShipPlotter. The first (the basin display) is a remote session to the PC that is connected to the AIS Receiver. its set to send data to the machine running the 3 monitors, and runs 2 instances of ShipPlotter. those 2 instances listen for output from the first on their own ports. then it was just a matter of adding the proper charts, and choosing the desired zoom level.
A big benefit to the 3 displays is that i now have a clearer view of traffic, and the ships render to scale. for clarity sake, i set the charts to be 75% transparent in ShipPlotter, which preserves readability, but makes the screen less cluttered.