If you have an Android tablet running Android 4.0.3 and up, you might want to check out this free app from NOAA. (I haven't tested it yet myself, as the Android tablet I've been using to test apps for almost 2 years won't run this one - guess I need to upgrade!) Download the app and get the free NOAA raster charts to see your position on the chart. A nice feature is the integration of the Coast Pilots. While the app doesn't offer chartplotter functions such as waypoints and routing, many sailors don't need these functions and it's enough just to see your boat on the chart. NOAA is releasing this version as a beta test until September, after which it will evaluate comments and decide whether to move forward with a fuller version for additional devices. For those whose Android device won't run this app, I'd recommend MX Mariner for Android or PocketNav for Apple, or check out these other navigation and other sailing apps.