[Steely Tom]

I thought it was caused by a badly brazed joint, and exacerbated when air filters were clogged by moisture that froze when they tried to blow the ballast tanks.

Welded joints had been weakened by underwater stress testing that had been carried out a few weeks earlier, involving setting off explosive charges at various distances from Thresher's hull.

[Red Badger]

The quality of the brazed joints was questioned when it was built and they ignored the warnings in favor of production schedule..................