I'm not that familiar with the
marinas, but grew up in Adelaide.
Most of the
marinas are around Port Adelaide. Some will allow you to
live aboard, but I'm not so sure which.
I'm pretty sure the Garden Island marina allows liveaboards, but it is a bit
remote and I don't think it gets public transport. All of the other marinas have reliable public transport to the city. I think the train is pretty close to most of them.
There is also a smaller marina at Glenelg, I'm not sure if there are casual berths, but it is on the tram line to the city.