Until the 1860s, the word torpedo did not mean what it means today. It referred to either floating bombs that would now be known as mines (such as those supposedly damned by Admiral David Farragut), or what are now called spar torpedoes (essentially a bomb attached to the end of a long pole projected from the bow of a warship). The modern torpedo, by contrast, is self-propelled and is therefore sometimes referred to as a fish or automobile torpedo.

Modern torpedoes trace their lineage back to the invention of a British engineer named Robert Whitehead. Born near Manchester, England, Whitehead emigrated to France in the 1840s to find work as a marine engineer. In 1847, he moved to Milan, then part of the Austrian Empire, but the following year of revolutions drove him to the Adriatic Coast, where he eventually settled in Fiume (now Rijeka, Croatia) and began building engines for the Austrian Navy. In 1864, a retired Austrian naval officer named Giovanni de Luppis brought him plans for a primitive wooden torpedo (called Der Küstenbrander, “the coastal fireship”). The design proved unworkable, but Whitehead was sufficiently intrigued with the idea of a torpedo to start from scratch. He produced a new prototype by 1866, powered by a unique two-cylinder engine of his own design and capable of making roughly 6 knots for 200 yards. The key breakthrough came in 1868, when Whitehead solved its erratic depth-keeping. The Austrian Navy, Whitehead’s patron, was delighted with the resulting improvements, but it could not afford to purchase the exclusive rights to the weapon.

Austria’s inability to purchase the exclusive rights to Whitehead’s torpedo opened the door for Britain. Both Whitehead and then-commander John Fisher (a future First Sea Lord) lobbied the Admiralty to try the device. It agreed, and trials were held in October 1870 with two torpedoes of different diameters. Overseen by a commission that included then-lieutenant A. K. Wilson (another future First Sea Lord), the trials were successful, and the Admiralty signed a nonexclusive contract to buy torpedoes from Whitehead’s Fiume factory in 1871. In 1872, the Royal Laboratory (subsequently the Royal Gun Factory) at Woolwich, which was controlled by the army rather than the navy, began building Whitehead torpedoes for the Royal Navy under license from Whitehead. In 1890, Whitehead established a second factory at Weymouth, on the south coast of England, to build torpedoes for his best customer. His original factory at Fiume continued to take orders from navies all over the world.

The United States was an exception. Instead of buying torpedoes from Whitehead, the US Navy attempted to develop a domestic counterpart in parallel. Its best hope was a torpedo known as the Howell torpedo, invented by a US naval officer named J. A. Howell. The Navy began to test it in 1870. In contrast to the Whitehead torpedo, which relied on compressed air, the Howell torpedo relied on the energy stored in a flywheel for propulsion. Aside from its propulsive effect, the flywheel also exerted a gyroscopic effect on the torpedo, improving its accuracy in the horizontal plane. While it experimented with the Howell torpedo, the US Navy flirted periodically with the Whitehead Company, but to no avail. Not until 1891 did it begin buying Whitehead torpedoes.