Simrad's AI50 is the most feature-packed Class B transponder available. Most obvious is the four-inch display with its world base map. It can serve as a standalone AIS target plotter, or as a useful adjunct to your regular nav system, which the AI50 can feed with target and GPS data either via NMEA 0183 or SimNet/NMEA 2000. Note that in practice it's valuable to have a here-comes-a-biggie zoomed out target display along with a more detailed chart/radar/target screen. Note too that the only other N2K Class B transponder currently available is the $1,149 blackbox NAIS-300 Simrad just introduced. The $1,595 AI50 also has the unique and desirable ability to use a target's MMSI number to "auto dial" the DSC VHF on its bridge. This feature currently only works if you have a Simrad SimNet VHF, but will hopefully become a NMEA standardized feature soon. The AI50 also supports SD memory cards which can be used to easily record and play back voyage and AIS data, possibly useful to convoy cruisers, fishermen, and insurance adjusters! Finally, the AI50 lets you tag buddy vessels that will then be highlighted if they come within AIS range (generally about ten miles for B transponders).
This article originally appeared in the January 2009 issue of Power & Motoryacht magazine.