June 11, 2009:
The U.S. Navy is expanding its re-inspection of welds on its recently built ships. Now the additional inspections will be performed on nine submarines and four Nimitz class carriers. This is all about quality control, or, rather, that lack of same. Recently, a weld inspector at the Newport News shipyard was found to be falsifying the inspection of welding jobs on four Virginia class submarines and a Nimitz class carrier. Some 10,000 welds have to be re-inspected, as these are how many the now dismissed inspector handled in four years on the job. Each Virginia class sub has about 300,000 welds that have to be inspected. Normally, only a few will fail inspection and have to be redone.
A few defective welds can cause the loss of a submarine, or serious damage aboard a carrier. Two methods are used to inspect welds, magnetism, or a special liquid. It's easy to fake the inspection, thus these quality control inspectors must be carefully selected.
Two years ago, the navy found some bad welds on a Virginia class submarine, and this led to some re-inspections. This problem goes back to the loss of the nuclear submarine Thresher in 1963, which was traced to bad welds. Reforms in how the welding was done, and inspected, seemed to have eliminated the problem, at least for about four decades. The current problem may, in part, be the result of changing the way welders are trained. In the last decade, training has come to include a growing amount of computer based instruction. In the past, all the teaching was one-on-one with an experienced welder teaching the student welder.