TRIPLE TUBES
The Russian Orfey-class destroyers, of which fourteen were built between 1914 and 1917 as modified versions of the Novik, were the first to mount triple torpedo tubes. They carried a total of three triple mounts for 18in torpedoes. Apart from the smaller size of torpedo, these gave the Orfeys a larger torpedo broadside than the slightly later US flush-deck destroyers.
Later designs of triple torpedo tubes returned to the Royal Navy during the late 1930s, for fitting to ‘Town’- and Dido-class cruisers. These were arranged as a horizontal group of three.
With four triple mountings for a total of twelve 21in torpedo tubes, the US ‘flush-deckers’ of the end of the Great War were the heaviest torpedo-armed destroyers of their day.
The Mutsuki class of first-class destroyers laid down under the 1923 programme introduced the triple tube to Japanese destroyers, in 21in calibre, later changed to 24in. The Fubuki class of super-destroyers were built with the 24in torpedo mountings, and increased their broadside from six to nine tubes (three sets of triple mountings).
After the new Emden (1925), which carried twin torpedo tubes, all modern German light and heavy cruisers built from the late 1920s onward were designed to carry a heavy torpedo armament of twelve tubes, in four triple mounts. Admiral Hipper and Blücher each carried ten reloads, and in Prinz Eugen the number of reloads was increased to twelve.
In the course of the Second World War, the surviving ‘K’-class light cruiser, Köln, plus Leipzig and Nürnberg, were considered of fragile construction and of little frontline combat value, and all landed torpedo mounts. Leipzig’s forward mounts were fitted on Admiral Hipper in 1941, to replace her starboard mounts which had been wrenched from the deck when HMS Glowworm had rammed the Hipper off Trondheim.
Scharnhorst and Gneisenau had been designed as battlecruisers/fast battleships, initially without torpedo armament, because of the risks involved in carrying them during gunnery duels. However, their initial commerce raids into the Atlantic indicated that they could profitably use torpedoes to despatch merchant ships which refused to sink under shellfire, allowing them to move against other targets in rapidly dispersing convoys. In March 1941 Leipzig’s after tube banks were removed and transferred to Gneisenau, while Scharnhorst received the after mounts which had been removed from Nürnberg a year earlier before the latter’s transfer to Norwegian waters.
QUADRUPLE TUBES
The torpedo outfit of Japanese heavy cruisers later changed from twin unshielded mountings to shielded quadruples, and the largest such as the Takao class had two quadruple mountings and eight reloads per side for a total of thirty-two 24in torpedoes. To cater for the wider quadruple mountings they were sponsoned out from the original ship’s sides. Each mount could train through a broadside angle of 105 degrees.
In preparation for the IJN’s pre-war battle plan for destroying the US Navy’s battle fleet (see Part IV), during 1941 the light cruisers Oi and Kitakami of the 5500-ton type were drastically modified to carry ten sets of quadruple 24in torpedo mounts, five on each broadside. With the change in tactics to fleet carrier actions, and the devastation caused to the US battle fleet at Pearl Harbor, these two conversions were never employed in their intended torpedo attack role, and they were altered once more. Kitakami became a carrier for 14m Daihatsu landing craft, and Oi was turned into a carrier and launch vessel for eight Kaiten.
The shielded quadruple Type 92 mount for 24in Type 93 torpedoes was also the classic armament of all the later Japanese super-destroyer classes other than the Shimakaze. The torpedoes were launched by compressed air, at a maximum tube pressure of 65psi (4.57kg/cm2), which would give a tube muzzle velocity of 40ft per second (12m/sec). In an emergency only, because of the resultant flash giving away the launch, 600g (1.3lb) black powder charges could be used instead, giving a similar muzzle velocity. Total weight of the Type 92 mounting, with shield but less torpedoes, was 18 long tons (of which the 0.118in/3mm thick shield accounted for no less than 3 tons). Each torpedo tube was constructed from mild steel plate 0.197in/5mm thick, with steel guides 2in/50.8mm wide running inside the whole length of the tube on each side and along the bottom. The tube doors were made of cast steel and locked by a steel ring rotated by a handwheel and gear rack.
Running depth was set in the torpedo by a spring-loaded plunger. The gyro angle was set by a handwheel, matching pointers on a gyro angle indicator. The setting spindle was inserted by hand but automatically withdrawn by an air piston arrangement when the torpedo was fired. No speed-changing device was fitted on the tubes. The only method of changing torpedo speed was by removing an access hole cover in the tube and inserting a small hand wrench. However, the torpedo speed was seldom altered as the Japanese favoured using the high-speed setting.
The torpedo was secured in the tube by forward and aft stops at each end of the T-guide on top of the torpedo. When loading the torpedo into the tube, the aft spring-loaded guide was forced up to let the torpedo enter. The forward stop was automatically lifted by an air piston when the torpedo was fired. The mount was normally trained using a 10hp 600rpm motor driven by compressed air at a pressure of 215psi (15kg/cm2). If necessary, it could be trained manually by two operators turning large handwheels inside the shield.