Normally, torpedoes were fired electrically from the bridge, tripping a lever which indicated on the bridge and at the mounting that the torpedo had been fired. If necessary, in an emergency the torpedoes could be fired manually from the mounting, using the Type 14 torpedo sight mounted on top of the tubes behind the observation port in the shield. The normal crew for a quad mount was nine men.
In order to maximise the use of their powerful 24in Type 93 torpedoes, the cruisers and destroyers were fitted with power reloading gear. On the destroyers four reload torpedoes were carried in watertight steel boxes adjacent to the tube mount, four beside the rear funnel for the rear mount and normally split two on either side of the forward funnel for the forward mount. Inside the steel containers the torpedoes were carried on sets of rollers.
The 10hp compressed air mount training motor was connected to a pulley via reduction gears, and loading cables attached to the tail of the torpedo pulled it from its container and into the tube. Speed of loading was almost 8in/20cm per second. The power reloading gear, under ideal training conditions with the destroyer motionless, could reload all four tubes ready to fire in three minutes. Under actual combat conditions, however, tactical considerations could require the destroyer to retire at high speed, often under fire and during a night action, in order to reload. In such circumstances, the average time to reload and return into action was between twenty and thirty minutes.
If the power loading motor was out of action it was possible to load the torpedoes manually, using ten men to haul on a rope wound to a drum. The fastest time to load each torpedo manually was around five minutes.
Concern was expressed as to the vulnerability to shellfire and bomb hits of the large Japanese cruiser and destroyer torpedo batteries. With compressed air-powered torpedoes, the Japanese felt that the effects of splinter damage were survivable, a splinter penetrating an air vessel causing only the escape of the compressed air. One must question this complacency in view of the various incidents detailed in Part V. Oxygen-fuelled Type 93 torpedoes, however, posed increased risks. If a splinter were to penetrate the oxygen vessel, the local heat generated could cause the torpedo to burn. If the fire was adjacent to the warhead this could explode.
To try to minimise at least the effects of shell and bomb splinters, the torpedo tube sides were given 5mm plates of light armour. The undersides and tops were unarmoured, but by training them fore and aft except when actually launching torpedoes, it was hoped to benefit from the protection offered by the ships’ superstructures. To protect against the cooking-off of the warheads, water hoses and an emergency water tank were situated near each mounting, and in the event of a fire the damage control parties were trained to play water on the warhead. If necessary, the damaged torpedo would be launched from the tube. These arrangements would work in exercises, but in combat situations too often the damage was uncontrollable, or the damage control parties were knocked out of action, and severe damage and even loss of the ship resulted.
On the night of 11/12 October 1942, during the Battle of Cape Esperance, the heavy cruiser Furataka was hit on her torpedo tubes by a shell, which set her on fire. She later sank following a torpedo hit. On 3 April 1943 at Kavieng, the heavy cruiser Aoba was hit by bombs from B-17s. Two of her torpedoes exploded, causing serious fires in one of the engine rooms. She was beached to prevent her from sinking. Later salvaged, Aoba returned to Kure for repairs, and was out of action until the end of November 1943. During the epic battle of Leyte Gulf on 25 October 1944, explosions of their own torpedoes doomed two Japanese heavy cruisers off Samar. At 0851 the 15,000-ton heavy cruiser Chökai was closing with the escort carriers of ‘Taffy 3’ when she was taken under fire by the destroyer escort Roberts and the single 5in stern guns on escort carriers Kalinin Bay and White Plains. It is believed that one of the carriers scored a hit on Chökai’s port torpedo tubes, starting a major fire. Eight minutes later the torpedoes exploded, knocking out the cruiser’s engines and steering. She sheered out of formation, and was then hit by a 500lb SAP bomb from an Avenger. Left dead in the water, Chökai had to be scuttled by torpedoes from the destroyer Fujinami.
A short while later, heavy cruiser Suzuya was near-missed by a bomb amidships on her starboard side. Splinters set fire to a torpedo in one of her starboard mounts, which exploded, spreading the fire to the other mounts and reload torpedoes. Ten minutes later these also exploded, damaging the engine rooms and one boiler room. Suzuya became unmanageable, and Vice Admiral Shiraishi transferred his flag to Tone. At 1150 ‘abandonship’ was ordered, and just five minutes later Suzuya’s remaining torpedoes exploded. She capsized to starboard and sank with more than half her complement of 850 officers and men.
The Royal Navy fitted quadruple 21in torpedo mounts to most of its interwar cruiser classes, beginning with the heavy Treaty cruisers of the ‘County’ class. There was some anxiety concerning the launching of a torpedo from the weather deck of such high freeboard ships, but in the event they suffered no undue problems. Certainly HMS Dorsetshire’s torpedoes ran faultlessly to strike Bismarck.
At the same time, RN destroyers changed over to quadruple tubes, beginning with the leader HMS Codrington, laid down on 28 June 1928, and continuing through the following ‘A’ to ‘H’ classes, except for Glowworm which mounted two quintuple tubes. In addition, the leader Inglefield, which was the first to mount quintuple tubes, lost the centre tube of each mounting when converted for Arctic convoy duties. The quadruple tubes were also standard on the ex-Brazilian and ex-Turkish ships purchased for Royal Navy service, and two quadruple mounts were to be the standard outfit of the majority of RN destroyers built during the Second World War.
With four twin 4.7in gun mountings, the RN ‘Tribal’-class destroyers maximised gun armament over torpedo armament, in an attempt to counter the Japanese super-destroyers of the Fubuki and later classes. So in a period when RN destroyers were starting to mount two quintuple torpedo tubes, the ‘Tribals’ reverted back to one single quad mount. The need for additional anti-aircraft firepower was the reason why the late war ‘Ch’-, ‘Co’- and ‘Cr’-class ships were designed with only one quad mount.
