The Super Flood Basin: A Novel Approach to Transforming a WWII Era Dry Dock to Support the Contemporary Submarine Fleet Now and into the Future

The U.S. Navy is undertaking the design and construction of a super flood basin at the Portsmouth Naval Shipyard (PNSY) in Kittery, Maine. The super flood basin is a 3.5 acre basin in front of an existing dry dock that artificially raises the natural river water level. Originally constructed for World War II era submarines, the floor of the Dry Dock 1 is too shallow for current operational requirements. Presently, the shipyard provides artificial ballast and is tidally restricted to less than a handful of days per month for docking and undocking evolutions at Dry Dock 1. For numerous reasons, these operations were not sustainable in the long term and the team considered many alternatives to address the challenge. This paper steps through the project including development of concepts, identification of design constraints, and design challenges. The current schedule has this project nearing completion by summer 2021.