You can easily use an inverter to go from 12v to 110V/240V and just use the stock adapter. Alternatively, you can get your hands dirty and do what I did [1]. However, I'm fairly certain that the non-maritime accounts won't be able to use the service on water (most likely geofenced) so that Starlink can sell their maritime version.
Maybe....maybe not... It depends if it will work using the new sat tech if it ever comes out. As it stands you just have a different (I wouldn't even say better) version of 4g....
[1]: https://blog.oxplot.com/powering-starlink-on-the-go-with-tes...
EDIT: looks like it's not geofenced based on some other people's comments who've been using the standard terminal on boats.