PORTSMOUTH, Va – After servicing and repairing hundreds of ships for almost 100 years, one of Norfolk Naval Shipyard’s oldest dry docks, Dry Dock 4, will soon get a major overhaul and top-of-the-line upgrades.
Age, deterioration, leaks, and broken parts played a critical role in the decision to rebuild the dry dock. “It all started in 2010 when the caisson seat (locked gate) cracked and 3,000 gallons of water were flowing into the dry dock every minute,” Code 984 General Engineer Brian Gray said.
After de-watering and in order to save the dry dock, personnel drove multiple large rods into the ground. Three feet of concrete was poured over the rods and bolted down for a second time.
“We did an immediate fix, but it was only temporary,” Gray explained. “With rising sea levels, hurricanes, nor’easter storms, and water pressure building behind the caisson, there is still a good chance it could leak again and cause more damage or shut down operations. That is why it is so important to design a dry dock that is protected from catastrophic flooding,” Gray said.
Storms and tidal flooding are the shipyard’s biggest threats when it comes to operations. It can cause a work stoppage which affects availability, getting the ships out on time, and costs a lot of money.
After analyzing permanent repairs for the caisson seat, Code 984 Long Term Planning and the Naval Facilities (NAVFAC) team discovered there was an opportunity to remodel and upgrade the 100-year-old dry dock to current standards.
After being briefed on the situation, Naval Sea Systems Command Logistics, Maintenance and Industrial Operations (NAVSEA) 04 and Commander, Navy Installations Command (CNIC) granted a $120 million, 33-month renovation project, and a temporary certification waiver to keep Dry Dock 4 operational until the USS Wyoming (SSBN 742) undocks.
Upon the submarine’s departure, the Dry Dock 4 project will begin. “It is going to be a lot of work, and after a few Planned Incremental Availability (PIA) stays, the new dry dock will pay for itself. It proves to be a good return on investment that is both valuable to the shipyard and the Navy upon completion,” explained Gray.
The Dry Dock 4 project will be done in two phases. The first phase will begin in Aug. 2019 with a scheduled completion date of Jan. 2020. The new construction will have a state-of-the-art caisson that allows water to flow through it during docking operations and a cofferdam that will hold back the Elizabeth River during dry dock reconstruction.
The second phase will begin Jan. 2020 with a scheduled completion date of June 2022. It includes construction of new caisson seat, removal and replacement of 30 inches of concrete from the dry dock floor, 24 inches of concrete from dry dock walls, redesign of utility systems and utility trench, and the addition of a flood and safety wall around the coping edge of the dry dock to meet new flooding requirements and needed upgrades to Dry Dock 4 pump well.
The newly designed dry dock will go from 144 feet wide to 132 feet wide, and have a state-of-the-art utility and computer control system. It will be able to dock all class ships for which it is certified, and is designed to increase the operational availability and decrease the duration of a shipyard Planned Incremental Availability (PIA).
“The changes and upgrades are going to leave a positive impact on the shipyard’s mission and give us the ability to provide better service to the ships so they can return to the fleet before or on time,” Gray expressed. “It will also allow leadership to tell Congress this renovation is going to increase fleet operational availability, is a huge cost savings for the shipyard, and built to last more than 50 years.”
“It is amazing how far we have come since Dry Dock 4 was built in 1919,” Gray added. “We are continually evolving with technology and innovation to meet the demands and mission of the shipyard and the Navy; it is simply incredible.”
Dry Docks 2, 3 and 8 are in the plans to be modernized and upgraded by 2040. Their reconstruction will go in phases, and receive upgrades based on their design and needs.
For more news from Norfolk Naval Shipyard, visit www.navy.mil/local/nnsy/.
Source: April Brown Norfolk Naval Shipyard Public Affairs Specialist | http://bit.ly/2tNQsjM