This story seems appropriate here. The contractor was the dad of someone I used to work with...
A contractor working on a nuclear sub noticed that the ships chronometer was a few minutes off. He set it to WWV, and didn't think any more about it. A few days later he noted that it was off by a few minutes again, this was way out of spec, so he started to get concerned. He set again and kept checking it. A few hours later, the CPO came in, glanced at his wristwatch and reset the chronometer by it.