This is the one I went with.
Very reliable and easy to use.
Simply plug it in.
I spent a bit more than Xort, 60 bucks versus 35.
Same one as PB, and as he has stated, not sure how it might react on your boat?
Courtney is My Hero
If a man is to be obsessed by something, I suppose a boat is as good as anything, perhaps a bit better than most - E.B. White