I did a lot of testing with many different products. What I found was:
1. You can't use a "wireless" amp on a
boat. That said, there's a chance it would
work if the outside
antenna was on the
mast - that might give enough separation although the line loss would take away a fair amount of amplification.
2. More expensive amps didn't
work any better than less expensive ones. In the end, I installed an inexpensive Wilson multi-band wired amp. I've had it for 5 years now and it still works perfectly.
With better
internet connectivity (if
WiFi is available) there are some new ways to do cellular
communications with femtocells. I just got one and I'm playing with it on my
boat this Fall to see how it works. It is a fantastic fit in our house - we get 0 bars inside living on the coast of
Maine. Turn on the femtocell and we get pinned-5-bars and have perfect cellular voice
communications. It requires a good
internet connection though. At our house, it's so good that we terminated our land line.