Looks like a small place. You'd have to run a top tier( expensive) in every way operation to operate profitably. High fees and fees for everything. No DIY only authorized subs and take a piece of that. Provide valet services--wash boat, provision boat every weekend, etc.

It's so expensive to keep up and run a legally-compliant marina. There's really little other way but to serve a clientele who enjoy( demand) paying for everything.