explicit purpose of hunting and destroying torpedo boats. Essentially very small cruisers, torpedo gunboats were equipped with torpedo tubes and an adequate gun armament, intended for hunting down smaller enemy boats. The first example of this was , designed by Nathaniel Barnaby in 1885. The gunboat was armed with torpedoes and designed for hunting and destroying smaller torpedo boats. She was armed with a single 4-inch/25-pounder breech-loading gun, six 3-pounder QF guns and four torpedo tubes, arranged with two fixed tubes at the bow and a set of torpedo dropping carriages on either side. Four torpedo reloads were carried. A number of torpedo gunboat classes followed, including the , the , the and the – all built for the Royal Navy during the 1880s and the 1890s. In 1891, a Chilean torpedo gunboat managed to sink the ironclad with a torpedo at the battle of Caldera Bay during the Chilean Civil War of 1891. This marked a milestone in naval history, as it was the first time an ironclad warship had been sunk by a self-propelled torpedoes. In the late 1890s, torpedo boats had been made obsolete by their more successful contemporaries, the torpedo boat destroyers, which were much faster. The first ships to bear the formal designation "torpedo boat destroyer" (TBD) were the of two ships and of two ships of the Royal Navy, ordered from Yarrows in 1892 by Rear Admiral Jackie Fisher. These were basically enlarged torpedo boats, with speed equal to or surpassing the torpedo boats, but were armed with heavier guns that could attack them before they were able to close on the main fleet. and were both built by Thornycroft. They were armed with one 12-pounder gun and three 6-pounder guns, with one fixed 18-in torpedo tube in the bow plus two more torpedo tubes on a revolving mount behind the two funnels. Later the bow torpedo tube was removed and two more 6-pounder guns added instead. They produced from a pair of Thornycroft water-tube boilers, giving them a top speed of 27 knots, giving the range and speed to travel effectively with a battle fleet. After the Russo-Japanese War, these ships became known simply as destroyers. Destroyers became so much more useful, having better seaworthiness and greater capabilities than torpedo boats, that they eventually replaced most torpedo boats. However, the London Naval Treaty after World War I limited tonnage of warships, but placed