To Overkill: I searched looking for a free app and everything I found was junk. I ended up paying the $14.99 for Navionics for my phone. Well worth the cost also it says $49.99 for tablet edition but I side loaded the phone edition to my tablet at no extra cost and have no problems with the quality on the larger screen. If you have multiple android devices on the same Google play account just log on to Google play and send the app to the device from there.
1. Buy the app for $14.99 for one device (Marine and Lakes - (US/Canada Edition)
2. log on to Google Play on a computer at
https://play.google.com/store3. Click on Apps
4. Click on My Apps (This will show a list of every app you installed with your Google play account even the ones that have been removed).
5. Find Navionics on the List and click on the green "installed" at the top
6. Pick the device on the drop down list at the bottom you want to side load it on and then click "install" and it will be pushed from the Google play site to you device.