from Mother Jones:
The Navy's new nuclear subs come with a special, expensive coating. Too bad it falls apart underwater.— By Adam Weinstein
Of all the complicated gadgets in the Pentagon's arsenal, a nuclear submarine is one that probably shouldn't be built on the cheap. Yet according to military analysts, that's precisely what the Navy and two defense contractors did with a series of $2 billion attack subs, and now they're literally dropping chunks of their protective skins into the briny deep.
The problem afflicts the Navy's growing fleet of Virginia-class subs, high-tech boats longer than a football field and armed with a dozen Tomahawk cruise missles. The subs are coated with a "special hull treatment," urethane tiles that are supposed to make them super-stealthy, reducing their noise underwater and absorbing sonar impulses. As these photographs show, and as the Pentagon's top weapons inspector has reported, the tiles have been peeling off of the subs while they're at sea, often in large sections. So far, missing tiles have been documented on four of the Navy's seven Virginia-class subs, the first of which launched in 2003.
The disappearing tiles won't sink the subs, but they could seriously impede their primary mission—to run silent and run deep without being detected. "When pieces of the hull coating fall off, the sub gets noisier because it interrupts the water flow over the hull," Norman Polmar, a defense analyst who literally wrote the book on Navy subs, explained to the Newport News, Virginia, Daily Press. "When you put more noise in the water, you're easier to detect." A blogger at Halibut Hangar, which discusses submarine systems, puts it more bluntly: "The submarine platform may purr like a kitten when delivered and roar like a lion after a subsystem failure." ..........(more)
The complete piece is at:
http://motherjones.com/politics/2010/09/navy-submarine-virginia-hull-problem