A torpedo boat is a relatively small and fast naval ship designed to carry torpedoes into battle. The first designs were steam-powered craft dedicated to ramming enemy ships with explosive spar torpedoes. Later evolutions launched variants of self-propelled Whitehead torpedoes.
Torpedo boats were (and still are) chiefly small inshore crafts created to counter the threat of battleships and other slow and heavily armed warships by using speed, agility, and powerful torpedoes. They presented an attractive alternative for smaller nations to the overwhelming cost and industrial strains involved in building a like number of capital ships to counter an enemy fleet. A swarm of expendable torpedo boats attacking en masse could overwhelm a larger ship's ability to fight them off using its large but cumbersome guns. A fleet of torpedo boats could pose a dire threat to an adversary's capital ships, albeit only in the coastal areas to which their small size and limited fuel load restricted them.