Submarine first-deep-dive mechanical stress relief

The hull welds of a new submarine are plastically deformed and stress-relieved on the first deep dive, on which the shipyard managers themselves are aboard — a quality-control incentive structure Tom highlights as exemplary.

When does the submarine see plasticity in its welds? The very first deep dive. And who gets to go on that dive? All the management of the shipyard. One of the best quality control techniques I've ever heard is, you send the managers on the first deep dive. They have to go — not all of them, but most of them, and I don't know if they draw straws to see who takes the chance, but they have real incentive to make sure, in the submarine shipyard, that they do good quality control, at least on the hull welds. Because they get to go on the first deep dive, and on that first deep dive you mechanically stress relieve the welds. So they do stress relieve them.