Torpedo tube
Torpedo discharge pipes or simply torpedo tubes (abbr. ToRo ) serve aboard warships of various types of storage and launching or firing of torpedoes (of fire speak would be wrong, because it is usually used no pyrotechnic propellant charge).
development
With the introduction of torpedoes as a weapon in the navy, torpedo tubes also appeared as a weapon for warships after 1860. They were initially referred to as torpedo launching tubes . They were first used on torpedo boats and torpedo boat destroyers . Later torpedo discharge tubes were installed on almost all types of warship ( destroyers , cruisers of all types, torpedo speedboats and submarines ), even some ships of the linecarried torpedo tubes. Initially, the torpedo tubes were also installed rigidly on surface ships, so that the whole ship had to be aimed. Some of them were even installed under the waterline. Later, on the surface ships (e.g. destroyers and cruisers), the torpedo tubes were combined in pivoting multiple sets (two, three or more tubes) on the upper deck.
The diameter of the torpedo discharge tubes varies depending on the type of torpedo and the measurement system used in the country of origin. In addition, the sizes of the torpedoes have increased over time. While torpedo tubes of 35 cm, 45 cm, 50 cm and 60 cm were used in the German Imperial Navy , the British Royal Navy used tubes with the inch dimensions of 15 inches (= 38.1 cm), 18 inches (= 45.7 cm) ) and 21 inches (= 53.3 cm). The latter established itself as a quasi-standard, so that the Reichsmarine joined in in 1927 and gradually adopted this measure for all torpedoes. The only exception for a long time was the Imperial Japanese Navy , which preferred 24 inch (= 61.0 cm) tubes.
Rocket torpedoes and appropriately shaped sea mines can also be ejected from the torpedo ejection tubes . In addition to the usual 53.3 cm, various submarine classes also use 65 cm tubes, through which nuclear-equipped torpedoes and anti- ship missiles can also be used.
On submarines, the torpedo discharge tubes are usually installed rigidly in the bow and stern of the ship's hull and closed by flaps in the rest position. Such pipes must first be flooded before the torpedo shot. Torpedo discharge tubes are sometimes also used to discharge combat swimmers through submerged submarines; They are also used as storage space for waste and for refrigerated storage e.g. B. used by provisions .
function
To this day, mostly compressed air is used to eject the torpedoes on surface ships, and pyrotechnic propellant charges on small torpedo boats . Steam was also used in the steamship era. Since the inside diameter of the torpedo tubes is slightly wider than the outside diameter of the torpedoes, the torpedoes are heavily greased when they are inserted into the tube so that the compressed air does not escape through the space between them. The discharge with compressed air technology is unfavorable for submarines, however, because a telltale surge of air can arise on the surface of the water.
For this reason, ejection methods have been increasingly used in submarines since the Second World War to solve this problem. For example, torpedo tubes were developed that only seal tightly at the mouth and the excess pressure is diverted back into the interior of the boat (very little air escaped), or the compressed air drove a piston behind the torpedo (the piston closed the tube at the end of its travel and held back the air in it). All these methods share the disadvantage that the internal pressure in the boat rises when the torpedo is fired, which can be uncomfortable for the crew, and the boat can get out of trim due to the tube being filled with air after the shot . Until the end of the Second World War it happened that after the torpedo shot, the bow of the submarine broke through the surface of the water and thus revealed the position of the boat.
To avoid this, z. B. the German Navy on their submarines so-called "drainage pipes", from which the torpedoes were not ejected at all, but simply the torpedo was launched in the tube and "drained" with its own engine power. These pipes had to be wider than the torpedo so that water could flow in from the front when it ran down. The torpedoes were guided over rails inside the tube. With this method, the torpedo must first slowly build up its speed and the high-revving propellers, which run at a standstill, cause telltale cavitation noises . Particularly interesting for small boats, this resulted in weight and space savings because the compressed air system for ejection was omitted.
Nowadays a technique is generally used in which the actual ejection takes place through water that is pressed behind the torpedo; the pressurized water is generated by a hydraulic cylinder or in special pressure chambers charged with compressed air (pressurized water discharge). The compressed air does not get outside or inside the boat, the process is practically noiseless. Except for the considerably larger and heavier technical equipment of the pipe, the pressurized water discharge has no disadvantages. Because with this technique the torpedo tube is filled with water after the shot, it is also easier to keep the boat in trim.
