by Sean Wu
The vast expanse of the world's oceans has always presented unique challenges for naval warfare. Nations have continuously developed advanced weaponry to overcome these challenges and maintain supremacy at sea, including in the underwater domain. Among the weapons produced in World War 2, the Type 93 Torpedo stands out as a formidable piece of naval technology due to its unique features, capabilities, and historical significance. Even though this new technology helped Japan sink many ships, its advantages would also be its downfall after a miracle discovery by the US Navy and scientists.
The Type 93 Torpedo, also known as the "Long Lance," was a wake-homing torpedo developed by Japan in the early 1920s. It was introduced as a successor to the Type 80 torpedo and represented a significant leap forward in torpedo technology. The development of the Type 93 Torpedo aimed to address the challenges posed by modern submarine warfare and provide the Japanese with a superior weaponry system compared to the United States. Earlier torpedoes used compressed air and alcohol to generate steam, which posed various problems. First of all, when the earlier models were traveling, bubble trails helped the enemies determine where they were headed and maneuvered to dodge them. Earlier torpedoes also had a shorter range, meaning that ships would have to get dangerously close to an enemy to get an open shot.
To solve these issues, Japanese engineers modeled the Type 93 on the Royal Navy's Mark 1 torpedo and took their innovation a step further. The Type 93 Torpedo had a length of approximately 9 meters (29.5 feet) and a diameter of 533 millimeters (21 inches). This frame was twice as large as any torpedoes in the world at the time, leading to the US giving the torpedo its nickname, "The Long Lance." It weighed around 2,700 kilograms (5,950 pounds) and carried 490 kg (1,080 lb) of Type 97 Shimose Powder, an explosive about 7% more powerful than pure TNT. The torpedo utilized a concentrated oxygen-fueled propulsion system instead of the former compressed air propulsion system. This improvement allowed it to achieve higher speeds and a longer range. It was considered one of the fastest torpedoes in the world at the time, capable of reaching speeds up to 96 km/h (60 mph) with an impressive operational range of over 50 kilometers (31 miles). It also employed an advanced wake-homing guidance system, which allowed it to track the wake disturbances left by surface ships, making it highly effective against surface vessels.
The Type 93 Torpedo offered several advantages over its predecessors and rival torpedo systems. The combination of its extended range and remarkable speed allowed the Japanese to strike swiftly and effectively, reducing the enemy's opportunity to carry out evasive maneuvers. In addition to its impressive speed, the torpedo was equipped with a wake-homing guidance system, improving its accuracy and reducing its interception risk. This feature enhanced the stealth of the Japanese Navy, allowing them to deliver lethal strikes without compromising their position.
The Type 93 Torpedo saw successful deployment in numerous naval battles and engagements. The Long Lance sunk the famous USS Hornet (CV-8) and countless Allied ships. When the torpedo debuted in 1942, Allied crews were often surprised when their ships were struck. The torpedo range was so large that Allied crews assumed they had been mined, torpedoed by a nearby submarine, or their ship had encountered some failure. Not knowing about the existence of the Type 93 at the time, many ships and crews went down without knowing what had hit them.
By the start of 1943, the Americans suspected the Japanese had a super weapon at their disposal. Still, it wasn't until the US Navy captured an intact Japanese warship that the Allies finally learned about the existence of the Type 93. After thoroughly inspecting the torpedo, they found some weaknesses. For example, the compressed oxygen stored in the torpedo as fuel was likely to self-detonate due to shock rather than hitting a ship. And as American airstrikes on Japanese ships became more common, Japanese commanders had to decide whether to keep the torpedoes on the ship and risk them blowing up due to shock or to jettison them. In the battle off Samar, the Japanese cruiser Suzuya was sunk due to the detonation of its Type 93 torpedoes after a bomb sent shock waves inside the ship.
The Type 93 Torpedo has had a profound impact on the strategic landscape of naval warfare. Its superior range, speed, and guidance systems have made it a sought-after weapon for Japan and other nations seeking advanced underwater capabilities. The development and deployment of the Type 93 Torpedo have prompted other naval powers to develop and improve their torpedo technology, contributing to an ongoing arms race in undersea warfare. The torpedo performed well against the Allies' Navies and sank 22 ships in total throughout its operational history. Although the torpedo had the disadvantage of self-detonation, the Japanese Navy thought that its capabilities outweighed its risks and continued to use it until the war came to an end in 1945.
DaveW. “Type 93 ‘Long Lance’ Torpedo Gyroscope: The National WWII Museum: New Orleans.” The National WWII Museum | New Orleans, 21 Aug. 2017, www.nationalww2museum.org/war/articles/type-93-long-lance-torpedo-gyroscope.
Stubblebine, David. “Type 93 Torpedo.” WW2DB, ww2db.com/weapon.php?q=386. Accessed 17 July 2023.
Dr. Friedman is the author of The Naval Institute Guide to World Naval Weapon Systems from the Naval Institute Press. “A Massive Torpedo.” U.S. Naval Institute, 5 Sept. 2019, www.usni.org/magazines/naval-history-magazine/2019/april/massive-torpedo.
IJN Torpedo - Long Lance, www.angelfire.com/blog/baileyfamily/NavyField/LongLance.html. Accessed 17 July 2023.