Japan's Yarrow-built Kotaka carried four 37 mm guns and six 14-inch torpedoes and was among the Japanese torpedo craft feared by the Russians in 1905. HMS Rattlesnake carried a four-inch gun, six three-pounders, and four 14-inch torpedoes, making her a Royal Navy attempt at a mixed torpedo gunboat. Her weakness was speed: about 16.75 knots under natural draft and 19.5 knots under forced draft. Spain's Destructor reached 22.6 knots with triple-expansion engines. She combined a 90 mm gun, four 57 mm guns, two 37 mm guns, and two 14-inch torpedoes. The designs balanced guns for fighting other small craft against torpedoes for threatening larger ships, but their limited speed left room for a faster successor.
Chapter · 30:16-32:27
Kotaka, Rattlesnake, and Destructor search for a gun-torpedo balance
Japanese, British, and Spanish experiments combined guns and torpedoes in different proportions while designers searched for enough speed and firepower to control the light-force fight.