I have a non-cellular iPad2 and use a Bad Elf bluetooth GPS. I like the Bad Elf, just wish it would work
with my Macbook, not just iOS devices.
The iPad has Navionics and Garmin
Bluechart both installed. Both are decent apps. Garmin
has Active Captain
integration which is nice.
Some other apps I use on the boat
Cruisers Forum...(I just downloaded Tapatalk and like it better)
Marina Life - a cruising guide
Knots - an admitted weakness of mine
The best use of the iPad is having it next to your head
when you're sleeping either off watch or at anchor
. Great instant situational awareness...comforting.