Story by Lt. Matt Karny
Officer in Charge of Construction-Portsmouth Naval Shipyard (OICC-PNSY) likes to say, “We are changing Google Earth.” Never before was this as evident as when the USS Cheyenne completed its docking evolution in Dry Dock No. 1 at the Portsmouth Naval Shipyard (PNSY) in Kittery, Maine, recently. The scope and size of the work done here is hard to imagine until seen firsthand. This event was years in the making, and the two projects that made it all possible are formally known as P310 Dry Dock No.1 Super Flood Basin and P1074 Extend Portal Crane.
Naval Facilities Engineering Systems Command (NAVFAC) is no stranger to important military construction projects, but the Navy’s Shipyard Infrastructure Optimization Program (SIOP) carries with it a huge mission impact. SIOP is a holistic plan that integrates all infrastructure and industrial plant equipment investments at the Navy’s four public shipyards to meet nuclear fleet maintenance requirements. SIOP will also improve Navy maintenance capabilities by expanding shipyard capacity and optimizing shipyard configuration.
SIOP is developing and executing an aligned, integrated and defensible strategic infrastructure plan to create the shipyard of the future. The program will develop area development plans for each shipyard to recapitalize dry docks, facilities and capital equipment for optimized industrial processes that best supports the nuclear fleet, including waterfront material/logistics, workflow and enabling technologies that directly return benefits to delivering ships back to the fleet on time. Since August 2021, when Rear Adm. Lore Aguayo, commander, NAVFAC Atlantic, commissioned the OICC-PNSY, the command has been responsible for providing robust on-site SIOP-related construction oversight and command-level accountability for resident engineering services, as well as coordination among shipyard and program stakeholders.
“The P310/1074 superflood project was technically challenging and had a diverse scope,” noted Andy Lemelin, the P310 construction manager. “There were several stakeholders involved, and all parties – from the designer to the contractor to the client and everyone in-between – working as a team, staying mission-focused to overcome challenges and meet the Navy’s needs.”
Among the many stakeholders at PNSY are those directly managing the Navy’s Los Angeles-class submarine Service Life Extension Program (SLEP). During the SLEP program, the Navy plans to refuel seven Los Angeles-class attack submarines. The USS Cheyenne (SSN-773) will be the first of the class to complete this program using the new dry dock complex completed under a separate NAVFAC contract.
“The Super Flood Basin enables Portsmouth Naval Shipyard the freedom and flexibility to dock and undock submarines from Dry Dock 1 when maintenance requires the ship to dock and undock, instead of being tethered to tidal cycles and the lunar calendar,” said Capt. Brian McLain, PNSY operations officer. “As I look into Dry Dock 1, and see USS Cheyenne (SSN 773) set precisely on the keel block [undergoing a complex maintenance availability], I see the product of engineers, mechanics, craftsmen, partnerships that made history at Portsmouth Naval Shipyard and ensures our ability to continue the tradition of delivering high-quality submarine maintenance to the United States Navy.”
So how does a shipyard with infrastructure dating back to 1800 move a submarine commissioned nearly 200 years later into a dry dock for a 10-year life extension?
The answer is simple, but not easy: enter the Super Flood Basin, a 165,000-square-foot, self-contained basin supported by three 20,000 gallon-per-minute pumps.
The basin enables vessels to enter the dry dock regardless of tidal influence. This was accomplished by constructing a basin just outside of the existing Dry Dock No. 1. When needed, the basin is flooded to a higher water elevation than the adjacent river providing adequate clearance between the bottom of the dry dock and the submarine’s keel as it enters its dry dock.
The basin allows dockings to occur when desired and in a controlled condition irrespective of the environmental factors of tide and current. The project included construction of closure walls to create the basin, structural improvements to multiple berths to support the super flood condition, a new entrance structure and surrounding crane and train rail infrastructure.
The crane and train rail infrastructure improvements are largely captured in the P1074 project that provides a new portal crane service to Berth 2, a berth external to the basin, in order to increase crane capacity on the berth. The project scope also included modernization of existing portal crane service around Dry Dock No. 1 and train rail into the refueling complex.
Some notable activities and considerations for this project included underwater explosive blasting, a new entrance structure, and multiple iterations of super flood basin testing to ensure that the basin operations would support submarine docking evolutions within all required tolerances.
In order to achieve proper tolerances and prepare for follow on construction, OICC PNSY conducted dredging and blasting. Given the vicinity of nuclear submarine facilities, significant coordination and approvals were required, all the way up to the CNO for a waiver from mandatory explosives safety requirements to enable the removal of bedrock by a commercial blasting contractor within the basin.
It took a team amassed from across the country and across systems commands to accomplish a monumental feat: the removal of 20,000 cubic yards of rock and another 40,000 cubic yards of other dredged materials, equivalent to the volume of eight Goodyear blimps’ worth of material. NAVFAC, along with Naval Sea Systems Command (NAVSEA), engineering consultants, contractors, and two different blasting subcontractors came together to assemble the plans and waiver, successfully completing the six-month program to blast and dredge the rock.
The new entrance structure during docking houses a caisson isolating the basin from the tidal influence of the Piscataqua River. The entrance structure is a 110’ x 60’ precast structure that is about 40 feet tall and supported by ten drilled shafts tied into the bedrock. This 5,800-ton structure, the size of three Olympic swimming pools stacked on one another, was pre-cast off site, delivered on a barge to PNSY, and lowered into place. The evolution took several weeks.
“P310 represented many firsts for the Navy,” said Linn Lebel, the team’s civil/structural engineer and project manager. “Implementation of an underwater blasting program on a shipyard, floating a caisson entrance structure into place, and, of course, the creation of the superflood basin.”
Kyle Bohunsky, the team’s design manager, echoed this.
“The design challenges of the superflood basin, a modern marvel contender, don’t stop when the construction documents are released, said Bohunsky. “It was an ongoing challenge. The success of the project is due to an incredibly dedicated team,” he says.
Although P310 was a significant event for SIOP-funded transformations at PNSY and the OICC, there is yet still more work to be done—a lot of work. As P310 & P1074 projects wrap up, and the successful docking of the USS Cheyenne is celebrated, OICC PNSY turns to its attention to the next mega project: P381, Multi-Mission Dry Dock No. 1, which was awarded for $1.73 billion, the largest construction project in NAVFAC’s history, which will continue to transform the superflood basin into two dry docks.
| Date Taken: | 08.23.2022 |
| Date Posted: | 08.25.2022 08:39 |
| Story ID: | 427999 |
| Location: | US |
| Web Views: | 603 |
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