An effective self-propelled torpedo before 1857

How would a viable self-propelled torpedo before 1857 change naval construction?

Torpedo craft and the destroyers built to counter them would appear and grow larger much earlier.

An effective self-propelled torpedo before 1857 would lead to much wider use of torpedo weapons. Torpedo-boat destroyers would appear sooner in response. They would also grow larger earlier as the threat increased. The scenario advances the development of both the weapon and the ships intended to counter it.