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Location: Patterson, New York | Subject: USS Toledo - Pressure Hull Crack
Experts: Toledo crew would have been safe
By Andrew Scutro - Staff writer - Navy Times
Posted : Saturday Jul 25, 2009 8:33:44 EDT
Crewmen of the attack submarine Toledo dodged what may have been a significant incident — or simply a puddle in the control room — when a crack in the ship’s pressure hull was discovered July 17 before getting underway from Naval Submarine Base New London, Conn.
A week later, Navy inspectors are still trying to determine the cause of a 21-inch crack on the topside hull of the Los Angeles-class attack sub, along with a “corresponding” 1-inch crack through the overhead of the control room, according to Naval Sea Systems Command.
The width of the crack was not released. “The crack’s exact geometry is being investigated,” said command spokesman Alan Baribeau said.
Because the pressure hull was compromised, “water would have entered Toledo if submerged,” said Lt. Patrick Evans, spokesman for Submarine Group 2 in New London.
“The Navy is conducting additional tests to determine the extent of the crack and the proper procedures to repair it,” Evans said. “After a cause is determined, other submarines will conduct similar inspections.”
While a hole in the skin of a submerged sub sounds disastrous, the scenario of seawater suddenly rushing through an expanding hole in the hull is unlikely, according to a retired submarine commander with extensive experience.
“I don’t see that it would fail,” he said. “Even if it happened later, when the ship was submerged, it wasn’t going to fail catastrophically.”
Submarine procedures during the initial dive require holding at 150 feet for about 15 minutes to check for leaks and establish neutral buoyancy. The retired commander said the crew would have likely discovered leaking water at that point.
“If the ship submerged in this circumstance, they would have seen dripping in that part of the ship,” he said, noting its location in the continuously manned control room. “From the perspective of ship safety, it’s nothing to get hysterical about.”
The larger question, he said, is where else in the fleet might there by similar failings, possibly as a result of poor quality control all the way back to the foundry. The crack was found in a casting, which is made from a mold, as opposed to the rolled steel that comprises most of the hull.
“The more important issue is: Why is this the case? Is it because we don’t understand some level of metallurgy?” he said.
A second retired commander agreed that the crew likely would have detected the leak quickly but said “it’s still shocking” that the crack would happen at all.
This is not the first incident in which cracks have been discovered in a U.S. nuclear sub.
Baribeau said that in 1995 cracks were found in missile-tube castings on the ballistic-missile sub Florida. In 1999, a crack was discovered in the bridge-access trunk casting of the attack sub Boise.
“The Navy corrected both issues immediately upon learning of the issues and will do the same for Toledo,” Baribeau said.
Toledo’s 25-month depot maintenance period at Northrop Grumman Newport News Shipbuilding in Virginia ended in February, taking about nine months longer than the standard DMP for the class. Baribeau said $268.7 million was spent on modernizing the sonar and combat control systems as well as maintenance, repair and preservation work. He confirmed the casting in question “had areas of corrosion repaired during the DMP.”
In 2007, Toledo was one of several Navy ships built or worked on at Newport News that needed close reinspection after faulty welds were discovered on non-nuclear internal piping in new Virginia-class submarines.
Other Los Angeles-class subs that needed inspection were the Oklahoma City and Newport News.
A Naval Sea Systems Command investigation is under final review. Baribeau said the crack is not connected to the 2007 weld issues.
Toledo is assigned to Submarine Development Squadron 12. It was built at Newport News and commissioned in 1995.
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USS Toledo - Pressure Hull Crack
