I use an IPad 2 32Gig WiFi only with Navionics but I also have other charts on it. Navionics is may primary software on my plotter so I stuck with it for continuity. The one critical thing..that I failed to do...was to buy a 3G/4G IPad. That is necessary in order to have an IPad GPS function. Since I did not I had to buy a stand alone GPS puck in order to have the IPad show the boat, course, heading, etc. Also, I have software called Marine Traffic, a sort of poor man's AIS, loaded but it too will not function away from a WiFi signal. You do not have to actually sign up with a Provider, Verizon, ATT, etc. in order to have the GPS work, the IPad just has to be the 3G or now 4G version. So, I would recommend a full size 3G/4G IPad mounted with a Ram swivel mount.