Today in history, December 7, 1941, is a major moment in the Second World War, when Japan successfully carried out a surprise attack on Pearl Harbor using a very well-planned and detailed strategy to avoid early detection by the United States. Japan in this attack carried out Operation Z, where the attack was planned with an extreme level of secrecy. Only a few high-ranking officials knew the details of the operation.
However, what we will discuss this time is more focused on the deadly weaponry that was successfully used in the Japanese attack on Pearl Harbor. What we mean is the Type 91 aerial torpedo which is iconic as a weapon carried by the Mitsubishi B5N2 “Kate” fighter bomber.
The Mitsubishi Kate took off from the aircraft carriers – Akagi, Kaga, Soryu, Hiryu, Shokaku and Zuikaku. In two waves of attacks, the Imperial Japanese Navy deployed a total of 144 Mitsubishi Kate units, including its two main models, the B5N1 and the more advanced version, the B5N2.
The Type 91 torpedo released by Mitsubishi Kate in the attack on Pearl Harbor hit and damaged several large warships, including the USS Oklahoma and USS West Virginia. Because the torpedo weighed 800 kg, the Mitsubishi Kate could only carry one Type 91 torpedo in one flight. Let's discuss this torpedo in more detail.
Aerial Torpedo Type 91
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| Aerial Torpedo Type 91 |
Although designed as a torpedo released from the air, apparently Japan still made modifications for the attack mission to Hawaii. The reason is that the waters in Pearl Harbor have an average depth of only about 12 meters, too shallow which tends to make the torpedo sink too deep after being released.
Japan added wooden fins to the tail of the torpedo. This modification functions to reduce the torpedo's sinking speed. Then the wood will keep the torpedo on the surface path so that it can reach the target effectively. These wooden fins are designed to disintegrate after entering the water, so as not to interfere with the torpedo's trajectory.
The Type 91 has a gyroscope stabilization mechanism to ensure the torpedo's trajectory remains straight after being launched, even in shallow waters. This torpedo is capable of speeds of up to 42 knots (around 78 km/h) with a range of around 2 km, effective enough to hit large ships in the harbor.
Historically, the Type 91 torpedo is an aerial torpedo developed by Japan in the early 1930s, specifically designed to be launched from aircraft. This torpedo was developed by the Imperial Japanese Navy in response to the increasing role of aircraft in naval warfare.
Japan understood that torpedo bombers could be strategic weapons in naval warfare. However, the torpedoes available at that time were too heavy or not reliable enough to be used by aircraft.
The Type 91 torpedo was produced by various shipyards and weapons factories operating under the control of the Imperial Japanese Navy. One of the main manufacturers was the Kure Naval Arsenal shipyard, which was famous for producing many of Japan's heavy weapons during World War II.
