Please look at ARTICLE 555 Marinas and Boatyards
This article covers the installation of wiring and equipment in the areas comprising fixed or floating piers, wharfs, docks, and other areas in marinas, boatyards, boat basins, boathouses, yacht clubs, boat condominiums, docking facilities associated with residential condominiums, any multiple docking facility, or similar occupancies, and facilities that are used, or intended for use, for the purpose of repair, berthing, launching, storage, or fueling of small craft and the moorage of floating buildings.
Private, noncommercial docking facilities constructed or occupied for the use of the owner or residents of the associated single-family dwelling are not covered by this article.
FPN:See NFPA 303-2000, Fire Protection Standard for Marinas and Boatyards, for additional information.
The remainder of this article includes the requirements and answers to the questions you ask. Good Luck!
Joe Tedesco, NEC Consultant