How about OpenCPN
(free) on your laptop
or netbook as a backup for your chartplotter
? Much more capable than any of the phones--I personally wouldn't want to be carrying around my backup chartplotter
in my back pocket all the time. Smart phones are huge theft magnets wherever things are dicey ashore too, plus chances are you won't easily be able to use it in many places you'll visit outside of the USA without the hassle of getting a local SIM card, etc., assuming your phone
is unlocked. Having said that, the phone
plotters are lots of fun and a good conversation starter at the bar.