Type 4 Ka-Tsu
| Type 4 Ka-Tsu | |
|---|---|
A Japanese Type 4 Ka-Tsu |
|
| General properties | |
| crew | 5–6 (commander, driver, radio operator, 2 × riflemen) plus 40 men or 4 tons of cargo |
| length | 11.0 m |
| width | 3.3 m |
| height | 2.8 m |
| Dimensions | 16 t |
| Armor and armament | |
| Armor | 10 mm |
| Main armament | 2 × Type 2 45 cm torpedoes |
| Secondary armament | 2 × Type 93 13.2 mm machine guns |
| agility | |
| drive | Air-cooled Mitsubishi A6120VDe 6-cylinder diesel engine 90 kW (120 PS) |
| Top speed | 20 km / h (road) 8 km / h (water) |
| Power / weight | approx. 5.6 kW / t (7.5 HP / t) |
The Type 4 Ka-Tsu ( Jap. 特四式内火艇カツ , Toku-yon-shiki ūchibitei Ka-Tsu ) was a Japanese swimming tank , the 1944 ( Kōki 2604, therefore, the type name) to 1945 by the Japanese Imperial Marine was used .
history
During the fighting in the Solomon Islands , the navy had considerable difficulties in supplying its troops with sufficient and efficient supplies. The lack of suitable landing stages forced Japanese ships to anchor some distance from the coast in order to bring the goods and soldiers ashore by ferry. In these situations, the ships and troops were exposed to a high risk of attack from the air and at sea. In order to reduce the transport time between ship and coast, the management of the Navy decided in 1943 to tender a buoyant, chain-driven vehicle that was suitable for such operations. The vehicle presented was given the designation Type 4 Ka-Tsu and was less of a floating tank than a lightly armored amphibious supply vehicle. The armor was limited to the areas in front of the driver and commander. A special feature of the Ka-Tsu was the hermetically sealed engine and electrical room. The reason for the sealing was the requirement to be able to bring the Ka-Tsu to its destination by submarine transport. It was planned to moor one or two Ka-Tsus on the quarterdeck of the submarine and approach the target submerged. The submarine should appear near the shore. The Ka-Tsus would then be loosened and swimming near and over the beach. The first Type 4 Ka-Tsu was completed in 1943 and the first successful driving tests were made in March 1944 off Kure .
Operation Yū / Tatsumaki
After successful testing of the Type 4, some naval officers suggested a daring plan that included the use of the Ka-Tsus. The military situation in the Pacific had developed more and more in favor of the Allies in early 1944 . The atolls of Eniwetok , Kwajalein and Majuro , which had recently been conquered by the Americans, have now been used as sheltered anchorages, in which the US ships were well protected from Japanese submarine attacks by the coral reefs. For this reason, the Ka-Tsu, armed with two torpedoes, should be dropped off by a submarine in front of the atoll, drive over the outer reef with its chains and attack the US battleships anchored in the atoll.
Captain Yamamoto Chikao, chief of operations of the Navy General Staff, was primarily responsible for planning the operation , which was called Operation Yū ( 雄 作 戦 , Yū sakusen , English "Operation Boldness"). His superior, Admiral Shimada Shigetarō , gave that for the 20./21. May 1944 the company planned to go ahead. When Yamamoto went to Palau for a briefing on March 26, 1944 , he was also able to convince Admiral Koga Mineichi , Commander of the Combined Fleet , of the success of the operation. Nothing stood in the way of execution. On March 31, Admiral Koga and his staff left Palau by flying boat . During the flight, the flying boat crashed and Koga and most of his staff lost their lives. The operation was put on hold until a new commander-in-chief could be found.
On May 1, 1944, Admiral Toyoda Soemu took over the management of the combined fleet. Two days later, he issued the order that Operation Yū must be carried out at no cost. With the support of the Navy General Staff, Toyoda ordered Vice Admiral Takagi Takeo to personally supervise the development of the company. The destination was supposed to be Ulithi Atoll , where several US aircraft carriers and battleships were suspected. As part of the subordinate Operation Tatsumaki ( 竜 巻 作 戦 , Tatsumaki sakusen , Eng. "Operation Tornado"), Takagi had five submarines, each provided with a Type 4 Ka-Tsu, practice diving exercises and torpedo attacks. The tests with type 4 were unsatisfactory. The noise of the engines of the Ka-Tsus could be heard for miles, they moved agonizingly slowly through the water and the chains fell off on the uneven ground at the slightest resistance. In addition, it turned out that, in spite of the sealing of the engine compartment, seawater penetrated into it and even threatened to flood the entire section.
On May 12, 1944, Vice Admiral Takagi reported the negative status of the preparations to the Navy General Staff, whereupon Operation Yū was postponed indefinitely until the malfunctions on Type 4 were resolved. However, the submarine I-36 continued with test dives with two Ka-Tsus lashed down until May 23, 1944.
Operation Yū was never resumed.
technology
The Type 4 Ka-Tsu was unarmored except for the front panels in front of the driver and the commander. Despite a length of 11 meters and a weight of 16 tons, it was hopelessly underpowered with an air-cooled Mitsubishi A6120VDe 6-cylinder diesel engine with 120 hp and reached a speed of only 8 km / h in the water. For the company Yū it should also be provided with two Type 2 45 cm torpedoes. These were normally used by torpedo boats and were equipped with the 350 kg heavy Type 97 warhead. A torpedo weighed about 1 ton and would have further reduced the speed of the Type 4 Ka-Tsu.
In total, only 49 copies of the Type 4 Ka-Tsu were produced.
Web links
- YU-GO: THE JAPANESE PLAN FOR A SECOND PEARL HARBOR SURPRISE ATTACK! David Dickson, Bob Hackett and Sander Kingsepp, accessed December 15, 2014 .
- Type 4 Amphibious Vehicle "Ka-Tsu". Taki's Page, accessed December 15, 2014 .
See also
literature
- Steven J Zaloga: "Japanese Tanks 1939-45" Osprey Publishing, 2007, ISBN 978-1-84603-091-8 .
- Hansgeorg Jentschura, Dieter Jung and Peter Mickel: "Warships for the Imperial Japanese Navy" Naval Institute Press, 1976, ISBN 978-0-87021-893-4 .
- Shizuo Fukui: "The Japanese Navy At the End of WW2" We, Inc., 1970.
Individual evidence
- ↑ a b Type 4 Amphibious Vehicle "Ka-Tsu". Taki's Page, accessed December 15, 2014 .
- ↑ a b Zaloga, p. 24.
- ↑ a b YU-GO: THE JAPANESE PLAN FOR A SECOND PEARL HARBOR SURPRISE ATTACK! David Dickson, Bob Hackett and Sander Kingsepp, accessed December 15, 2014 .
- ↑ I-36 Japanese Submarine. PacificWrecks.com, accessed January 21, 2020 .
- ↑ Jentschura, Jung, Mickel, p. 272