Your
ownership of the
boat is distinct from the Federal "documentation" of the boat, or of a State titling or
registration of a vessel.
Documentation is merely Federal titling and
registration, it is not
ownership, nor is it actual proof of ownership.
Documentation avails perfection of mortgagee liens associated to a vessel and thus aids in
financing. Additionally, Federal documentation conveys nationality to a vessel [i.e. "Flagging" under UNCLOS].
There are often delays in the processing of agency procedures and filings, whereas ownership transfers when the contractual terms are complete. And there are specified periods of time after a change of ownership upon which notification of ownership transfer has occurred before the new owner has to register or document the change in ownership.
Your momentary situation is rather similar to having title [ownership] to property but not having yet deeded the title, or having patenting of the title, or recordation of the title.
The agreement as to use or ownership of a slip in a marina is a separate contractual arrangement and should not be delayed or become a factor of either the ownership of a vessel that is placed in the slip, or as to completion of Federal documentation, or as to State registration.
If you own the vessel than all rights AND responsibilities, obligations and liabilities associated therewith are yours, including where and how it is moored. The conveyance of ownership, leasing or rental of a slip is another matter entirely.