Gulf Marine Fabricators started a pump-down operation. A Min-Dock structure--a miniature dry dock utilized to work on the underside of a ship--failed during Phase One. The floor of the dock lifted up and broke apart. This resulted in catastrophic damage to large construction equipment including pumps located within the structure. Because of the damage, water pressure from the bay was pressing against the damaged floor and threatening to lift it, which would further increase the damage. Rocks and other large debris were used to temporarily keep water out of the Min-Dock, but the water needed to drain to begin repairs.