Attack sub North Carolina leaves Newport News for trials

NEWPORT NEWS

 With top officials from the Navy and Northrop Grumman Newport News aboard, the attack submarine North Carolina left the shipyard’s pier Wednesday for its first sea trials. 

 Intended to test the sub’s systems and capabilities, the trials were delayed for several days while the Navy and the shipbuilder scoured its interior piping systems for faulty welds.

“The Navy inspected all of North Carolina’s critical, high-energy systems and found no issues,” said Katie Dunnigan, a spokeswoman for Naval Sea Systems Command in Washington.

The scrutiny is the result of a Navy investigation that began in October. It uncovered weaknesses in how the Newport News shipyard welded together non-nuclear piping on the Virginia-class submarines.

Welders at the yard had been allowed to carry two types of metal weld fillers, each for different types of piping systems. The Navy and the shipyard discovered that some welders had erred by using a copper alloy filler to weld corrosion-resistant steel joints, a mistake that can cause the joints to crack and leak.

In addition, welders who realized they had made mistakes were allowed to gouge out the copper alloy and replace it with the proper weld filler – leaving behind trace amounts. That practice has been stopped, and now welders are allowed to carry only one weld filler per job, the shipyard said this week.

The shipyard also said it has ordered all welders and welding foremen to undergo eight hours of training, followed by an exam on welding procedures.

The problem came to light after two piping joints on the submarine New Hampshire failed during routine testing at General Dynamics Electric Boat in Groton, Conn., which has a teaming arrangement with Northrop Grumman to assemble the subs. The New Hampshire, the fifth of the Virginia-class subs, is still under construction.

Navy officials said it’s too early to know how extensive the problem is, but they’re now saying it may not be as serious as initially thought.

No welds have failed on the three Virginia-class subs now in service, the Navy said.

Of  the first of the class, the Virginia – in service since October 2004 – the Navy said it has found and replaced one copper-contaminated piping weld. An additional weld is being investigated on the Texas – the first delivered by the Newport News yard, in June 2006.

Officials also discovered one contaminated weld on the New Mexico, which is under construction and will be the third in the class delivered by Northrop Grumman.

Before sending the North Carolina to sea Wednesday, the Navy and shipbuilder assessed about 15,000 piping welds, shipyard spokeswoman Jennifer Della­penta said.

“The North Carolina would not have gone out to sea if there was any question about the quality of the welds,” she said. Besides the submarine’s crew of about 137, others aboard for its first ocean run included shipyard President Mike Petters and Rear Adm. William Hilarides, the Navy’s program executive officer for submarines.

Neither the Navy nor the shipyard would say how long it will be at sea for the so-called “Alpha trials,” comparable  to taking a new car on a test drive. It will be submerged for the first time, conduct high-speed runs, and undergo other tests of its design, systems, components and compartments.

After it returns, it will go for a second trial run designed to test its weapons systems.

Dellapenta said the shipbuilder still expects to deliver the North Carolina to the Navy in January, a few weeks past its December contract date.

Jon W. Glass, (757) 446-2318, jon.glass@pilotonline.com