January 25, 2010: Last year, the U.S. Navy discovered problems with the quality of welds in submarine and aircraft carrier construction. Now it has found even more widespread problems with weld quality on amphibious ships. Poor quality control allowed 10-15 percent of welds, that were substandard, to get passed. This produced pipes and structures that will fail under conditions where they should not. These welds are not in critical areas, as with some of the questionable submarine welds, but they will cause more maintenance problems, and may already be causing problems with leaks on new amphibious ships. Substandard welds mean ships spend more time laid up being refurbished, and have their useful life shortened.
Last year, the navy ordered additional weld inspections for nine submarines and four Nimitz class carriers. This was all about quality control, or, rather, the lack of same. For example, last year 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 had 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.
The navy is also concerned with the quality of management in shipyards building warships. The ship building firms deny that there is a management problem, which may turn out to be the biggest problem of them all.