An assembly for budding a pre-fabricated modular boat dock structure is disclosed. The assembly is designed to be modular so it can be fabricated in a shop environment and then installed by assembling it on site. The assembly is further designed to enable the individual component modules to be powder coated prior to installation so that the pre-fabricated modular boat dock will be rust resistant and have a much longer expected lifespan than a custom boat dock which is built on site would have. The pre-fabricated modular boat dock structure has a pleasing aesthetic appearance after having been powder coated and is useful in extending the life of a boat dock structure used to shelter boats stored immediately adjacent to a body of water.