Abstract: An enclosure having a bottom plate, a wall, and an opening to pass a portion of a pier into the enclosure. A first sealing member coupled to the bottom plate. Watertight tanks coupled to the enclosure float the enclosure in a body of water, at a position above a footing of the pier with the portion of the pier in the enclosure, sink the enclosure to compress the first sealing member between the bottom plate and a ledge of the footing, and re-float the enclosure. A method includes floating and navigating the enclosure to the position and adding weight to sink the enclosure. A plurality of adjustable length structures may be lengthened to exert a downward force on the bottom plate to secure it to the ledge. A second sealing member may be forced into the opening between the pier and wall of the enclosure to facilitate dewatering the enclosure.