I had an iPad II laying around and no real use for it, so on a whim I bought an Emprum USB GPS for it and the Navionics software, right before a 2 week trip to Tahiti
. There's several other GPS modules you can, add and I'll admit, I only picked Emprum because I could get it next day. It worked fine though. The only limitation with a GPS attached to the iPad is that you pretty much had to be in the cockpit
to initially acquire the signal.
Overall, it worked amazingly well, and after the trip everyone wanted the info on the setup so they could replicate it. Navigating with it was super easy, and we pretty much didn't want to move the boat without having it in the cockpit
(although we still set up the chartplotter
down below for longer passages and we kept paper charts).
The only thing I would have added was a splashguard case, for when things got a little wet up in the cockpit. I bought one from trendydigital.com, but I haven't had a chance to try it out yet. I also ended up buying
the iPhone version of the Navionics software for day sailing
in my local area, but I haven't had a chance to use that yet either.