Chilean Civil War: The armored frigate Blanco Encalada was sunk at the Battle of Caldera Bay, the first ironclad warship lost to a self-propelled torpedo.

The Chilean Civil War of 1891 was a civil war in Chile fought between forces supporting Congress and forces supporting the President, José Manuel Balmaceda from 16 January 1891 to 18 September 1891. The war saw a confrontation between the Chilean Army and the Chilean Navy, siding with the president and the congress, respectively. This conflict ended with the defeat of the Chilean Army and the presidential forces, and with President Balmaceda committing suicide as a consequence of the defeat. In Chilean historiography the war marks the end of the Liberal Republic and the beginning of the Parliamentary Era.

Blanco Encalada was a central battery ship built by Earle's Shipbuilding Co. in England for the Chilean Navy in 1875. She was nicknamed El Blanco. She participated actively in the War of the Pacific, her most important action being the capture of the Peruvian monitor Huáscar during the Battle of Angamos.

The Battle of Caldera Bay, or the Sinking of Blanco Encalada, was a naval engagement fought in the Caldera Bay during the 1891 Chilean Civil War between Balmacedist and Congressional naval forces on 23 April 1891. It involved two Balmacedist torpedo boats of the Almirante Lynch-class, and the Congressional armored frigate Blanco Encalada.

A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such a device was called an automotive, automobile, locomotive, or fish torpedo; colloquially, a fish. The term torpedo originally applied to a variety of devices, most of which would today be called mines. From about 1900, torpedo has been used strictly to designate a self-propelled underwater explosive device.