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Portsmouth Naval Shipyard Dry Dock No.1 Super Flood Basin

Detailed engineering and design for the continued modernization of a shipyard critical to submarine maintenance

  • Kittery, Maine

    Kittery, Maine

Enhancing the ability to perform critical maintenance and life-extension work on the Virginia Class fast attack submarine fleet

Stantec has partnered with the Portsmouth Naval Shipyard for decades, supporting facility needs for modernized and expanded waterfront and landside infrastructure. At present, Virginia-class submarines can only safely access the shipyard’s Dry Dock No.1 with the use of buoyancy assist tanks—an outmoded and risky operation.

To bring access up to modern standards, we’d create an outer navigation lock basin that lifts the submarines naturally, also known as a super flood basin. Strong currents in the tidal Piscataqua River estuary presented a key design challenge as tidal conditions can be problematic for vessels entering and departing. To assess how flow patterns might affect a submarine’s ability to safely navigate, our team built a numerical hydraulic model of the basin entrance. We then deployed current meters and ran 2D and 3D models to predict hydrodynamic drag at critical times and locations to establish the range of safe operating conditions. Additional components of the project included protecting the dock’s utility galleries with watertight closure walls, maintaining heavy-lift crane access to the submarines, and major utility and site restoration work.

The creation of the super flood basin means Portsmouth Naval Shipyard can now lift submarines without the use of buoyancy assist tanks allowing for safe, direct entry to the dry dock.

At a Glance

Meet Our Team

Mike Govoni, Principal

To be effective in this profession, you should learn what other disciplines do and how they’ll affect the work you’re doing.

Paul Harrington, Vice President

A good designer needs to understand and appreciate how things are built—constructability is a critical element of our designs.

Tony Pregel, Navy Account Manager

I am proud to have served my country for 24 years and I am fortunate to work with Stantec to continue to serve communities across the globe.

Brian Shea, Senior Principal

A good team leader knows how to delegate and can recognize the strength of each coworker. Building the right team means project success.

Doug Stewart , Senior Principal, USE Regional Sector Leader, Environmental Services

Building dynamic teams to help our clients succeed in a world where they are challenged by new and changing environmental regulations/policies is key to our success.
Doug Stewart Senior Principal, USE Regional Sector Leader, Environmental Services Read More

Mike Govoni


Paul Harrington

Vice President

Tony Pregel

Navy Account Manager

Brian Shea

Senior Principal

Doug Stewart

Senior Principal, USE Regional Sector Leader, Environmental Services

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