From your post, it sounds as if you wouldn't be buying
a slip, but someone else's place in line to rent a slip. If there is a long waiting list for a Santa Barbara municipal slip, that makes some sense, but if there is no such long wait, it makes no sense at all. Just contact the city agency that oversees the harbor and get the information directly from the horse's mouth, as it were.
In many places where there had been full marinas
and long waits, the sagging economy has changed all that. Not only is the wait list gone, in some locales they are even lowering slip fees to get the marina filled again. I don't know about Santa Barbara, though - that's a pretty desirable location with a lot of deep pockets in residence, so there may indeed be a long wait there, still.