The Navy’s new submarine coating process seems to be achieving better results than the one that was apparently causing major disbonding on several Virginia-class subs in recent years.
Hundreds of square feet of thick, black hull coating peeled off the first three of four subs in the class, the Navy admitted in September. The problems dated to 2007, published reports said.
Most affected were the USS Virginia (SSN 774), the USS Texas (SSN 775), and the USS North Carolina (SSN 777).
The sharkskin-like hull treatment had sonar-absorbing properties that prevented the sonar waves from bouncing back to the sub emitting the signal, helping it elude detection.
Mold in Place
The Navy said the problem had “not measurably affected” the subs’ performance, but it began a comprehensive review of the coatings application process.
According to the Newport News, VA, Daily Press, the problem was a newer application method known as “Mold in Place,” in which coating was applied to the subs “in large swaths, creating a smoother surface.”
The process replaced one in which hull coatings were formed by a series of tiles that were glued individually across the boat’s exterior in a patchwork pattern, the newspaper said.
Seawater pressure weakened the tile bond over time, however, and the coating would disbond. The “Mold in Place” method was “thought to be cheaper, faster and more durable,” the Daily Press explained.
But “Mold in Place” also resulted in disbonding while the subs were underway, the Navy said.
The result was “hundreds of square feet” of coatings problems, among other “fail-to-sail” issues, in the Virginia class, according to a letter written June 30 by J. Michael Gilmore, director of operational testing and evaluation, to Ashton B. Carter, the Pentagon's acquisition chief. The letter was reported last year by the Connecticut news site theday.com.
‘Issues Are Behind Us’
The Navy won’t discuss its newest application process but says it seems to be working.
"Clearly, we had problems on the early ships," Vice Adm. Kevin M. McCoy, commander of Naval Sea Systems Command, the Navy's ship-buying and maintenance arm, told the Daily Press. "We think, for the most part, those issues are behind us."
The applications process "has gotten much better improved in terms of temperature controls, humidity controls and adhesion," McCoy told the newspaper, adding that he was “very confident going forward” that the current coating would adhere satisfactorily.
Affected submarines are being fixed during their normal dry-dock maintenance periods, the newspaper noted.
The coatings are applied during construction by Northrop Grumman Corp. and General Dynamic Electric Boat, but the Navy specifies the application process, the newspaper said.