I have a III Plus and it works fine. I don't see where it has a marine
application though. For $120 plus $9 shipping I'd be happy to sell you my
Micrologic ML150 which is a real marine handheld with a built in world map,
built in lights and bouys and a daily tide chart for wherever your boating. It
has a larger screen with a higher resolution than the Garmin. It runs off 4 AA
batteries or the supplied 12 volt power cable if you want to fix mount it. It
is like new in the original box with owner's manual, power/data cable, swivel
mount and bridge card. It sold for $799. I bought a fixed mount chartplotter.
S/V Express 30 "Ringmaster"
Trains are a winter sport