During World War II , the Japanese army had a hard time maintaining the operation of its war machine because Japan's own materials were insufficient to support such a large-scale war and needed to plunder resources from other occupied countries. Sea transportation was the only effective mode of transportation, but in the US military submarine Under the attack of , the routes became extremely unsafe, and the Japanese army was unable to organize naval forces to conduct all-round escorts. Merchant ships often had to save themselves. For this purpose, Japan specially developed the 20 cm L12 short naval gun (hereinafter referred to as the 20 cm gun). ).
0 cm gun is envisioned as a simple-to-operate multi-functional artillery, mainly installed on merchant ships with a displacement of less than 5,000 tons, or installed on high ground near important facilities such as ports. It can serve as a general artillery as naval gun , The coastal defense gun can also be used for air defense, , anti-submarine, and . In short, it is a multi-purpose gun. Generally speaking, if a weapon can do everything, then it probably can't do anything well. The 20cm gun is almost like this. The actual caliber of the
artillery gun is 20.32 cm, using a 12-times diameter barrel. An artillery system weighs about 4 tons. The design of the artillery focuses on simple operation, because most of its users are sailors who lack professional training, and their skills are obviously different from those of regular soldiers.
The artillery is installed on a rotating base. It uses mechanical means to complete horizontal rotation and barrel pitching. Although the operation is simple, it is very cumbersome. The horizontal rotation and pitching are only about 8°/second. If used for air defense, the reaction must be too clumsy. The artillery pitching The angle is -15°~75°. The barrel is equipped with a hydraulic spring recoil mechanism, and the breech adopts an intermittent thread locking method to fire separate ammunition with a propellant charge of 2 kilograms.
The ammunition it can use include high-explosive bombs , anti-aircraft bombs, and incendiary bombs. The weight of these ammunition is about 50 kilograms. Among them, the high-explosive bombs contain nearly 13 kilograms of explosives. The explosive power is considerable. After all, the caliber of the artillery is very large. over there.
Because of the short barrel and less propellant, the initial velocity of the ammunition is only about 305 meters/second. This speed obviously cannot pursue long effective range and beautiful ballistics. It has an effective range when firing high-explosive bombs. About 6,300 meters, when launching anti-aircraft missiles, the effective range against the air is 3,300 meters, and the combat distance is very close. However, its -15° depression angle is not bad. If a merchant ship hides such a heavy gun , it will pose a great threat to submarines that surface and try to attack merchant ships with deck guns. One shell is enough to severely damage the submarine.
's introduction to the gun mentioned that its rate of fire is nearly 5 rounds/minute. This statement has not been recognized because the gun's warhead of about 50 kilograms is not light. In actual operation, it needs to be operated with the help of corresponding lifting equipment, and it needs to be Lowering the gun barrel to an elevation angle of 10° before operating it is difficult for even a skilled artilleryman to achieve in actual combat unless the operation is repeated at an elevation angle of 10°.
Japan built a total of about 250 20cm L12 short naval guns during World War II. The number was not large, and it also showed the predicament the Japanese army was in at that time. Most of the photos that have survived currently show the artillery installed on land for combat, such as Guam , it was used as a defensive artillery piece, and the real thing is still preserved here.
There is actually a smaller version of the 20cm gun, which is the 12cm L12 short naval gun. Its function is the same as the 20cm gun, but its range and power are much smaller. The maximum anti-air range is 2800 meters. The maximum range to the ground is 5300 meters.
The weight of a single-seat 12cm gun is nearly 2 tons. It is relatively light. It was built in larger quantities, about 550. At that time, the Japanese army also tried to install it on the Type 97 tank as the self-propelled artillery , or assault. Cannon .
Whether it is a 20cm gun or a 12cm gun, the overall performance of these two artillery is not very good. They can only be regarded as emergency weapons. They do not play a very important role on the battlefield, and they are not able to stop the Allied actions. .
