The Mark 14 torpedo's testing failure

Was the US Navy bad at designing torpedoes or at testing them?

Testing was the greater failure: the Mark 14 design appeared strong, but realistic trials did not expose or force acceptance of its interacting defects soon enough.

The Mark 14 provides an example of the gap between a persuasive design and a weapon proved through testing. Small discrepancies in manufacture or operation still had to be discovered in practice. Confidence in the design helped explain resistance to accepting that the finished torpedo had problems. A counterfactual failure of the widely fitted 5-inch/38 gun would have been much more visible to officers across the fleet. The comparison concerns how readily a defect becomes apparent and creates pressure on the Bureau of Ordnance to act.