Abstract: The boat cleats of the invention are typically mounted on the watercraft and docks adjacent to the water for tying watercraft to piers as well as to other watercraft and disclose a solar powered modular structure supported within a boat cleat mechanical housing support structure. This arrangement provides savings associated with the provision of through-the-dock wiring access, easy removability for replacement, maintenance and servicing, and which is sealed against the environment. The self contained solar powered modular structure may have communications capabilities to enable distributed control and sensing.