In Southeast Asia and the Solomon Islands in 1942, the activity of Allied torpedo boats was a major factor in the operations of the Japanese army and navy, with small ships with powerful firepower often causing trouble at landing sites and even sinking destroyers on the Tokyo Express. In view of the inability of the existing light ships to resist the attacks of Allied torpedo boats, the Japanese also began to develop similar gunboats/torpedo boats to counteract. Funnily enough, before that, the Japanese Army went it alone again, independently developing small high-speed gunboats, and then the Navy in turn borrowed the Army's design.
The "Destroyer" and "Yi High-Speed Boat" that were born after this were distinguished from other small ships by their high speed and strong armament, which were used for escort/transport/anti-submarine operations, and their theoretical survivability was also stronger.
Destroyers
In 1941, the Japanese Army began to develop the so-called "High-Speed Boat C" as a follow-up to the previously developed high-speed boats. However, in operations in Southeast Asia, it was found that the previously developed high-speed boats could not counter the attacks of Allied torpedo boats, and often allowed opponents to come and go unhindered - due to the fact that the high-speed boats were too fragile and the speed of the armored boats was too low. As a result, part of the design of the high-speed boat C was changed to add the function of an anti-torpedo boat, and it became the so-called destroyer. In other words, it is MGB (according to the classification of the British).
From the design point of view, the shape of the destroyer itself is almost a common torpedo boat in the 40s, but the army will not develop torpedoes ~~
The destroyer has a displacement of 16 tons, a length of 18 meters, a width of 4.3 meters, a draft of 0.59 meters, a capacity of 13 people, and the main engine is two 850 horsepower Kawasaki Ha-9 aero engines (imitation BMW VI, interestingly the Japanese wiki claims to be "89 type 800 horsepower engine", but I couldn't find this number of liquid-cooled engine), reached a speed of 37.5 knots in the test, and a cruising range of 180 nautical miles. It is equipped with two Type 98 20mm anti-aircraft guns, two depth charge slides (10 rounds of ammunition, depth charges are kindly sponsored by the Navy Red Deer) and two smoke screen generators, and it is also equipped with a simple underwater listening device (ら device) for the army DIY.
It looks quite reliable, and the Navy also referred to the hull design and layout of this thing when developing the Type B torpedo boat. In early 1943, the Army built a test boat, and then after the second test boat was tested in the second half of the year, the Army was satisfied that it could be put into production.
The original model, officially classified as the Destroyer I, was produced in late 1943-early 1944 and performed exactly as planned, with about 40 units produced. However, after the stock of engines was exhausted, it had to switch to a 650-horsepower Type 97 air-cooled engine, and at the same time two depth charges were added, and the 20mm guns in the front were replaced by one 37mm boat gun, resulting in a decrease in speed of 1.3 knots, for the destroyer type 2, and about 20 ships were produced after August 1944.
Similar in design to the MTBs of the Japanese Navy
As for the experimental prototype in 1944, which was switched to an 850-horsepower engine on the basis of Type II, it was named Destroyer Type III, the displacement rose to 21 tons, and only prototypes were produced.
The most daring was the destroyer Type IV, which was built as an experimental boat in the form of waterjet propulsion, and only prototypes were built. In addition to the 650-horsepower Type 97 air-cooled engine, there is also a 65-horsepower diesel engine - used as a cruising and emergency power to prevent the engine from being destroyed, and the armament has become a four-type 20mm twin-mounted anti-aircraft gun, one plus one 37mm boat gun.
Do you think that the Army just raised its eyebrows and made the Navy kneel and sing about conquest? No, because that's how they were designed......
Why would the engine drive these two propellers directly on the deck!! I feel so retarded~
If it weren't for the picture, I guess it would be said to be blown
It is claimed that the speed of the test can reach more than 30 knots, but due to lack of resources, this model was not able to be put into production, but the photos left are enough for curiosity lovers to enjoy:
The only unambiguous photo of the destroyer Type IV
Motor......
The destroyers are mainly equipped with the 1st Maritime Destroyer Brigade (code: Xiao 16708) of the Army Marine Force, which was established in December 1943, and is organized into the headquarters of the Maritime Destroyer Brigade and 5 Maritime Destroyer Squadrons, each of which has 6 squads (1 destroyer each), with a full complement of 30 ships.
The 2nd Squadron of the 1st Battalion was driven out by sea and participated in the Battle of Okinawa, but the 2nd Squadron of the 1st Squadron participated in the Battle of Okinawa, but the status of the ants was useless and suffered heavy losses in the Allied air raids, and the main force remained in the Japanese mainland until the surrender of Japan.
In addition, the maritime transport team under the umbrella of the Marine Mobile Brigade was supposed to be equipped with 10 destroyers, but it was never actually equipped.
I-go high-speed boat
In 1943, the Japanese Army felt the inconvenience of transporting supplies to the front line, so it began to conceive a small boat that could be quickly transported to the front line islands and had a certain self-defense capability. In September 1943, the Army built an experimental boat in Yokohama, and another prototype entered service in March 1944.
The so-called I-hull is a wooden hull with a displacement of 97 tons, a length of 33 meters, a width of 5 meters, and a draft of 1.26 meters, and the main engine is three and two 850-horsepower Kawasaki Ha-9 aero engines, three-axle propulsion, a speed of up to 23 knots, and a cruising range of 1,000 nautical miles. The crew is 15 people, 13 gunners, and the armament is 3 4-type 20mm twin-mounted anti-aircraft guns, 2 depth charge slides and improvised underwater hydrophones (ら device), which can carry 40 tons of cargo and 20 tons of fuel.
The army was pleased with the results and immediately began mass production. But soon the engine was not enough, and it was only possible to change to a 650-horsepower engine like a destroyer, while the width was increased by 0.8m, and the displacement increased to 105 tons. The armament was changed to 1 20mm twin anti-aircraft gun and 1 37mm boat gun. Because of the power attenuation, the speed is only 19 knots.
The I-ship high-speed boat type, note that the A gun position is actually a 20mm gun
Prototype of the I-go high-speed boat
Drawings of the I-II high-speed boat
After entering service, the Yi high-speed boat received the name of the Type 5 high-speed conveyor boat, and a total of about 60 ships were produced. In practical application, the Yi high-speed boat was organized into a high-speed transport boat brigade, with six detachments under its jurisdiction, each with one command boat and five transport boats. Thereinto:
After October 1944, the 1st and 3rd Detachments were used as transport missions to the mainland-Okinawa, and after the start of the Battle of Okinawa, they were transferred to the Japanese-Korean line until surrender.
The second detachment was responsible for supplying Hachijo Island after April 1945.
The sixth detachment went to the Philippines, but was sunk by air strikes on the mainland, and then suffered losses due to bad weather.
The fifth detachment went to Singapore and stayed until the surrender, which, oddly enough, did not cause any big news.
As for the fourth detachment, there was never a ship equip, just empty shelves.