Completion of the submarine North Dakota, seen Nov. 2 just before its christening ceremony, is being delayed to address design and construction issues. (US Navy)
WASHINGTON — Problems with a parts supplier and the need to modify certain design features led the US Navy to announce Wednesday that the commissioning of the new nuclear-powered attack submarine North Dakota won’t take place at the end of May as scheduled.
“This decision is based on the need for additional design and certification work required on the submarine's redesigned bow and material issues with vendor-assembled and delivered components,” the Naval Sea Systems Command (NAVSEA) said in a statement.
The delay is a blow to the Virginia-class submarine program, which has built a reputation not only for on-time performance, but for delivering ships in advance of the contracted delivery date.
The submarines are built jointly by General Dynamics Electric Boat in Quonset, R.I., and Groton, Conn., and by Huntington Ingalls Newport News Shipbuilding in Newport News, Va. Each company builds certain components of every submarine — essentially a 50-50 split — and the yards alternate in assembling, launching and completing the subs. The North Dakota, launched last September, is being completed by Electric Boat.
Both shipbuilders declined to answer specific questions about the problems on the North Dakota, deferring to the Navy.
Although the North Dakota’s contracted delivery date is in August, EB was aiming at a mid-May delivery. Cutting weeks or months off the building time usually results in major cost savings to the Navy and a bonus to the shipbuilder.
Completion of the North Dakota is significant. Although the ship is the 11th Virginia-class sub, she is the first of the Block III variant, with a redesigned bow section featuring two Virginia Payload Tubes (VPTs) and a reconfigured sonar sphere containing a Large Aperture Bow array. The innovative VPTs are able to store and launch a variety of weapons or vehicles, and the configuration does away with 12 fixed tubes able to handle only a limited weapon selection.
It is not clear if the VPTs or the sonar system are affected by the vendor issues.
NAVSEA would not identify the vendor, although sources said it was a subcontractor to Newport News.
“The Navy is withholding the company’s name until the investigation is complete,” said Lt. Kurt Larson, a NAVSEA spokesman. “The vendor in question provided components to other Virginia-class ships, though not in the same degree as North Dakota,” he added. “Components delivered to now in-service ships passed initial testing and the Navy has not experienced any issue with them to date.”
Larson said a routine inspection of assembled components on the North Dakota turned up problems with the supplier’s quality control, and subsequent inspections revealed further issues. As a result, “a prudent review of all components from this vendor” is being carried out. The work is extensive.
“There are 58 components the Navy is currently investigating aboard the North Dakota,” Larson said. “These components include stern planes and rudder rams, retractable bow plane cylinders, hydraulic accumulators, high-pressure air-charging manifolds, torpedo tube interlocks and shaft/link assemblies, weapons, shipping and handling mechanisms, and other miscellaneous parts.”
Inspection of these parts and systems does not mean problems have been found with them, Larson cautioned.
“To ensure the safety of its crews and ships the Navy will ensure the components from this vendor meet specifications,” he said.
Larson could not provide a date for when the issues came to light, nor comment on projected costs.
“The issue is still under investigation, so it’s premature to discuss costs,” he said.
Sources said problems with the vendor have been fixed, although it is not clear if the vendor remains under contract. With only a limited number of suppliers qualified to build parts for the submarine program, options may be hard to come by, sources said.
The Navy also may be thinking about making design changes to the VPT installation, although details are not clear. The new bow was designed by Electric Boat, which also makes the weapon tubes.
The sub had been scheduled to leave Groton April 14 to begin Alpha sea trials, also known as builder’s sea trials. Now, the vessel is expected to have to be drydocked to enable its systems to be inspected. No new dates have been set, although neither the Navy nor the shipbuilders expect the delays to take too long.
“We still expect to deliver the ship ahead of the August contract delivery date,” EB spokesman Bob Hamilton said.
Here’s the full NAVSEA statement released by the Navy April 16:
By Team Submarine Public Affairs
WASHINGTON — The PCU [pre-commissioning unit] North Dakota (SSN 784) commissioning will be postponed, the Navy announced April 16.
This decision is based on the need for additional design and certification work required on the submarine's redesigned bow and material issues with vendor-assembled and delivered components. As the Navy works with all vested parties to certify the quality and safety of the submarine and toward taking delivery of the boat, it will determine a new commissioning date. The Navy is committed to ensuring the safety of its crews and ships. High quality standards for submarine components are an important part of the overall effort to ensure safety.
The lessons learned from North Dakota are already being applied to all Block III submarines.
Team Submarine oversees the submarine force's research, development, acquisition, maintenance and life cycle support.