Due to a family emergency I flew back to see my mother in Mozambique, and bought myself a Samsung Galaxy Grand Prime Pro for about $140USD. This video is a demonstration of the GPS receiver performance on this phone that costs about 10% as much as my previous one.
Thanks to Android OS I now have access to OpenCPN which is a brilliant free chartplotter app for Android. It is available on the Play Store at this link:
https://play.google.com/store/apps/details?id=org.opencpn.opencpn_free
If you want to download worldwide CM93 charts supported by OpenCPN for free, here you go:
https://drive.google.com/file/d/1nkaMudyIstNDUSc3XXR-rxV-f-jlDu9x/view?usp=drivesdk
Beware that these charts are not 100% up to date. That said, they still work perfectly as a backup. I only had these charts when I reached Brasil and used them to navigate through the buoyed reef channel and up the Paraíba river without any deviation to what I was looking at.
For up to date marine charts I highly recommend you buy a Navionics subscription for the area you plan to sail around. These subscriptions are valid for 1 year and they are also available from the Play Store, this is the one I have at the moment:
https://play.google.com/store/apps/details?id=it.navionics.singleAppCaribSAmerica
I hope you enjoy.