Shin'yō (explosives class)

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Shin'yō
A Shin'yō as a single-seater (Type 1 Mod. 1) with an open engine compartment
A Shin'yō as a single-seater (Type 1 Mod. 1) with an open engine compartment
Ship data
flag JapanJapan (naval war flag) Japan
Ship type Explosive boat
Shipyard various
Launch March 1944
Whereabouts retired
Ship dimensions and crew
length
5.10 m ( Lüa )
width 1.65 m
Draft Max. 0.30 m
displacement 1.40
 
crew 1
Machine system
machine 1 Nissan or Toyota
Machine
performance 		67 hp (49 kW)
Top
speed 		23 kn (43 km / h)
propeller 1 (three-leaved)

The Shin'yō ( Japanese 洋 , dt. "Seebeben") explosive boats, also called Maru-You in Japanese usage , were a type of explosive device developed for the use of kamikaze by the Imperial Japanese Navy and the Imperial Japanese Army , which was in the final phase of the Second World War against Allied ship targets. They were used until Japan's surrender on August 15, 1945. The Japanese army also developed its own type of explosive device called Yon-shiki nikuhaku kōgekitei ( 四 式 肉 薄 攻 撃 艇 ), or Marure for short , which, however, was not designed from the outset for use in kamikaze.

development

The development of the Shin'yō began in the spring of 1944 and followed the demand of the Imperial Japanese Navy to develop a cost-effective concept in order to be able to successfully repel an Allied invasion of the main Japanese islands . The primary weapon of the explosive device was an explosive charge weighing 270 kg, which was attached to the bow of the ship and which exploded with an impact fuse. The main shipyards of the explosive device were:

The monthly production level was between 400 and 600 boats. The number of units rose to around 6,200 boats by spring 1945. However, the construction did not only take place in mainland Japan, but was also promoted in the areas annexed by Japan. For example in Java , the Philippines , Shanghai and Singapore .

Structuring and recruiting

recruitment

The crews for the boats were sought in the middle schools so that the target group were boys aged 15 to 16 years. The incentives for the pilots included, in addition to fast transport and the associated privileges, the prospect of a financial contribution to the family after a successful assignment.

structuring

Experienced marines were given to command the explosive boats driven by the young people. In the Japanese Imperial Army, the units were structured as follows:

  • Battalion (Gyro Tai)
    • Division command (14 men)
      • Company with 30 men and 100 boats
      • Company with 30 men and 100 boats
      • Company with 30 men and 100 boats.

Produced variants

Type variant Specifications
prototype The prototype of the Shin'yō was built as a series in March 1944, which included eight boats. Six of them were made of plywood and two of metal. Extensive tests were then carried out by both navy and army personnel. The prototype had a length of 6 m, was 1.67 m wide, had a draft of 0.33 m and was designed as a single seater. The first test took place on May 27, 1944. However, the performance was unsatisfactory because too much water got over the bow into the hull during the test, so the naval management gave the order to develop further versions of the boat with a new bow shape which, however, had to be made of plywood for cost reasons.
Type 1 The Type 1, the real prototype, was 6 m long and 1.65 m wide. With a displacement of 1.35 t, a 67 hp engine accelerated the boat to 26 kn. This made a driving range of 103 nm possible. 270 kg of Type 98 explosives (60% TNA 40% HDNA ) were stored in the bow of the ship and were to be detonated by two detonators from Japanese mines. The pilot could ram the target and an electric percussion detonator triggered the explosion, he could also trigger this detonator himself electrically at the push of a button, or the mechanical detonator, which was triggered by a rip cord, was used.

The sub-variant of type 1, the "modification 1", which was developed to solve the problems with the bow shape, had a hull shortened to 5.10 meters in length, displaced 1.4 tons and received a steel cable that ran from bow to tip a pole at the stern and should function as a net deflector . Two unguided 12 cm missiles could be fired from simple wooden launchers that were mounted on the fuselage next to the pilot. The main weapon, however, remained the explosive charge in the bow. The pilot had a steering wheel, engine controls, the device for detonating the explosive charge and a simple magnetic compass . These type 1 boats went into series production.

Type 2 Type 2 was a wooden hull hydrofoil developed by Y. Otsu and final assembly at Yokohama Yacht Works. The boat was powered by an internal 67-horsepower Toyota engine and was 6 meters long. The planned speed of 30 knots was never reached by the test models. The elaborate construction showed stability problems and only achieved a peak performance of 18 knots. Therefore, this type was not pursued any further and production was discontinued.
Type 3 The only information about the Type 3 was that it was to receive an outboard motor, but was never produced.
Type 4 No Type 4 was developed because the number four is considered an unlucky number in Japan .
Type 5 The Shin'yō , designed as a guide boat , had a wooden hull, was 6.50 meters long, 1.86 meters wide and had a displacement of around 2.15 t. The two Nissan engines mounted in the stern, each with an output of 67 hp, accelerated the boat to approx. 25 kn, which allowed a driving range of 114 nm. It was designed as a two-seater and received a radio for its management tasks. A 13 mm machine gun was used for close-range defense, and the two unguided 12 cm missiles that had already been used in the Type 1 were also installed. In the bow area of ​​the ship, the 270 kg explosive charge of the type 1 boat was placed again. The trials began in September 1944.
Type 6 The sixth variant of the explosive device, which was produced by Mitsubishi, could not get beyond a few prototypes before the end of the war. The design was intended to solve the previous problems with the inefficient engines from automobile production, which provided little power for their comparatively high weight. The hull of a Type 1 boat was reinforced and experiments were carried out with a propulsion system that was powered by a fuel supply similar to that of the Type 93 torpedo . For the Type 6, however, a jet engine should be used that should run on a mixture of fuel and hydrogen peroxide . The prototype initially reached 50 knots, but then went up in flames as a result of a fuel leak and an engine overheating and finally went down.

Two other Type 6 subtypes were tested to optimize the drive configuration. In modification 1, the number of injection nozzles in the engine was reduced to three large feed tubes and water cooling was provided for the engine. The speed should reach 100 knots and the fuel supply should allow a short sprint of 4500 meters. The prototype reached 70 kn, but was already destabilized by small waves and badly damaged in the subsequent tumbling motion . The Mitsubishi designers wanted to solve the problem by installing small wings on the fuselage of modification 2, but this did not provide a sustainable solution to the problem.

Type 7 The Type 7 was a parallel development to Type 6 by the Imperial Navy in Yokosuka. Type 7 was not intended to be operated by a jet but by rocket engines . It was decided to use the ten rocket engines as they were also used in the Yokosuka MXY-7 . The drive provided thrust for ten seconds and should be able to propel the Type 7 for a distance of 3500 meters. The tests in February 1945 were unsatisfactory because the boat cut under the bow at around 60 kn and overturned. The program was abandoned.
Type 8 Was an enlarged version of the Type 5 and should have a crew of three. With a length of 8 meters, a speed of 23 knots was achieved with three conventional engines. Type 8 was not intended as an explosive device, but was intended as a torpedo boat to fire two 28 cm Type 5 torpedoes with a range of 1500 meters at its targets. At the point in the bow where the predecessors carried the explosive charge, the fuel tank was installed. It was to be mass-produced from October 1945.

Structure and use

A Shin'yō is tried out by an American soldier after the end of the war

At the beginning of 1945, 1950 units were available to defend the Japanese mainland and were distributed as follows:

  • 325 boats in Hosojima
  • 125 boats in Aburatsu
  • 500 boats in Kagoshima ( Kyushu Island )
  • 50 boats in Sakumo
  • 175 boats in Sumosaki (Shikoko Island)
  • 775 boats around Tokyo ( Honshu Island ).

With this force, the Japanese naval command had calculated, a possible Allied invasion fleet should be able to be attacked for ten days and nights. These incessant attacks were intended to weaken the enemy fleet so that continuing an invasion would seem useless. However, the Shin'yō were only ranked third, behind the Kaitentorpedoes and the micro-submarines (such as the Kuryo type ) in the priority list for repelling an invasion by naval forces. The explosive boats acted primarily as diversion or support boats. During the conquest of the island of Karene , the Allies first fell into the hands of 390 undamaged explosive devices destined for Okinawa.

In the Battle of Okinawa , the Imperial Japanese Navy lost around 700 explosive devices, most of which could still be destroyed in their bases. The defense strategy of the American naval forces was also based on the early warning system by the radar, which made large-scale attempts at Japanese containment seem futile. Many Japanese units were also destroyed from the air by units of the Air Forces , whose aircraft carriers were mostly within air range, but outside the sphere of activity of the explosive boats. Another method of defense against the explosive vessels was to block occupied ports with rows of pointed stakes, which were intended to destroy the hulls of the attackers.

Way of attack

The way the boats attacked was mostly similar to that of comparable explosive boats from other navies, which, however, were mostly not used for kamikaze operations. To avoid noise, the pilot should approach the target with his Shin'yō at crawl speed or with stopped engines and paddles. Shortly before the destination or when discovered, he should approach the ship at full throttle. The boatswain had the opportunity to jump backwards shortly before the impact in order to save himself. Most of those who succeeded, however, were killed or drowned by the blast as the massive Allied superiority prevented Japanese rescue attempts. Most of the survivors were taken prisoner of war. For their courage, the surviving crews as well as the bereaved by kamikaze actions of those who died in some cases still enjoy considerable prestige today.

successes

  • January 10, 1945 ( Gulf of Lingayen )
    • Assault boat USS LCI (G) 365 (sunk)
    • Landing craft USS LCI (M) 974 (sunk)
    • USS War Hawk (badly damaged)
    • Landing craft LST 160 (badly damaged)
    • Landing craft LST 925 (badly damaged)
    • Landing craft LST 1025 (badly damaged)
    • Destroyer ?? (slightly damaged)
    • Landing ship ?? (slightly damaged)
  • January 31, 1945 ( Gulf of Manila , 30 explosive boats deployed)
    • Patrol boat PT 77 (self-sinking due to false detection signals)
    • Patrol boat PT 79 (self-sinking due to false detection signals)
    • Patrol boat PT 1129 (sunk)
  • February 15, 1945 (Marivles Bay)
    • Support landing craft USS LCS (L) -7 (sunk)
    • Support landing craft USS LCS (L) -8 (badly damaged)
    • Support landing craft USS LCS (L) -26 (sunk)
    • Support landing craft USS LCS (L) -27 (sunk)
    • Support landing craft USS LCS (L) -49 (sunk)
  • April 4, 1945 (Okinawa)
    • Landing craft USS LCI (G) -82 (sunk)
    • Landing craft USS LSM-12 (sunk)
  • April 29, 1945
    • Support landing craft USS LCS (L) -37 (badly damaged)
  • May 4, 1945
    • Transport ship Carina 10,000 GRT (badly damaged)

losses

The Japanese records list 2,557 deaths among pilots and support teams.

Evidence and references

Remarks

  1. ↑ The information relates to the type Shin'yō 1 Mod. 1, which went into series production.
  2. ↑ 1.65 or 1.67 meters depending on the source

literature

  • US Naval Technical Mission to Japan, Report S-02, Japanese Sucide Craft. 1946.
  • Robin L. Rielly: Kamikaze Attacks of World War II. A Complete History of Japanese Suicide Strikes on American Ships, by Aircraft and Other Means. McFarland, Jefferson NC et al. 2010, ISBN 978-0-7864-4654-4 .

Web links

Individual evidence

  1. ↑ Kamikaze Attacks of World War II, page 80.
  2. ↑ USNTMJ S-02, page 7.
  3. ↑ USNTMJ S-02, page 8.
  4. ↑ USNTMJ S-02, page 12.
  5. ↑ USNTMJ S-02, page 8.
  6. ↑ USNTMJ S-02, page 12.
  7. ↑ USNTMJ S-02, page 9.
  8. ↑ USNTMJ S-02, page 1.
  9. ↑ USNTMJ S-02, page 14 and following.
  10. ↑ USNTMJ S-02, page 16.
  11. ↑ USNTMJ S-02, page 18.
  12. ↑ USNTMJ S-02, page 18.
  13. ↑ Harald Fock: Naval small weapons. Manned torpedoes, small submarines, small speedboats, explosives yesterday - today - tomorrow. Nikol, Hamburg 1996, ISBN 3-930656-34-5 , pp. 108-111.
  14. ↑ asahi-net.or.jp, viewed on January 22, 2011