When torpedoes began changing warship design

When did underwater weapons such as mines or torpedoes begin to affect ship design?

Their major practical influence emerged with the Whitehead torpedo and the destroyer threat, which pushed large ships toward batteries of rapid-firing defensive guns.

The answer distinguishes older uses of the word torpedo, which could mean a mine, from the self-propelled Whitehead weapon. Once destroyers could carry such weapons toward major warships, designers had to consider stopping the attacking craft before they reached launch range. The immediate response discussed here was not yet a fully developed underwater-protection system. Instead, capital ships accumulated quick-firing guns intended to suppress torpedo craft during their approach.