For Marine Navigator you can just copy your existing .kap maps onto a pendrive and copy the content over to your tabletīs BSB_ROOT directory.
There is no OruxMaps Desktop
app available as yet for the conversion of the .kap maps,but you could do the conversion at home and upload the OruxMaps files to your cloud drive for later access,ANYWHERE you have internet
access. The sames goes of course also for all your .kap files. Perhaps your Marina has WiFi
I keep all my OruxMaps and MarineNavigator maps on my Google
cloud drive and only download to my tab as required to save RAM space. The same for Route
.gpx files from my now comprehensible library. I use the ES File Explorer
app which is the only file manager I know which can also transfer files between my tab and my cloud drive.
The FREE AutoAppOrganizer will handle this exchange automatically once you have installed your apps and files. Just delete the app or maps when no longer required and AutoAppOrganizer will let you click the app or maps directly on your cloud drive and install them in their original places.
You can even install your own choice of icons downloadable from GooglePlay. I have organized MINE like the attached.