From Wikipedia, the free encyclopedia.
| (insert image and caption here) | |
| General Characteristics | |
|---|---|
| Displacement: | 46 tons submerged |
| Length: | 23.9 meters (78.5 feet) |
| Beam: | 1.8 meters (6 feet) |
| Height: | 3 meters (10.2 feet) |
| Ballast: | 5899 pounds in 534 11-pound lead bars |
| Designed Depth: | 30 meters (100 feet) |
| Propulsion: | one electric motor, 600 horsepower at 1800 rpm, two screws conter-rotating on single shaft, leading prop 1.35 meters diameter, right-handed; trailing prop 1.25 meters diameter, left-handed |
| Batteries: | 192 trays of two two-volt cells each, 136 trays forward, 56 trays aft |
| Endurance: | 100 nautical miles at 2 knots, 80 nautical miles at 6 knots, 18 nautical miles at 19 knots |
| Speed: | 23 knots surfaced, 19 knots submerged |
| Complement: | one commander, one crewman |
| Armament: | two 18-inch torpedoes muzzle-loaded into tubes, one 300-pound scuttling charge (big enough not only to destroy the sub but to disable any ship it was near) |
Twenty ko-hyoteki were built. The "Type 'A' Target" name was assigned as a ruse -- if their design was prematurely discovered by Japan's foes, the Japanese Navy could insist that the vessels were battle practice targets. They were also called "tubes" and other slang names.
The first two, Ha-1 and Ha-2, were used only in testing. They did not have conning towers, which were added to the later boats for stability underwater.
Ha-19 was launched by the I-24 at Pearl Harbor. Most of the other hull numbers are unaccounted for, although several were captured in Sydney (Australia), Guam, Guadalcanal, and Kiska Island, accounting for some of the other hull numbers.
On December 7, 1941, five ko-hyoteki joined the attack on Pearl Harbor, having been carried there by I-16, I-18, I-20, I-22, and I-24.
Photographs taken by Japanese aviators during the attack appeared to show a ko-hyoteki inside Pearl Harbor firing torpedoes at Battleship Row, but subsequent research has disproven this theory.
I-16tou, commanded by Masaji Yokoyama and crewed by Sadamu Uyeda, radioed on the evening of December 7 a report that the attacks had been successful, and was credited with the sinking of USS Arizona (BB-39), although in truth it was a high-level bomb dropped by a Kate from the aircraft carrier Hiryu that caused the sinking. The light cruiser St. Louis (CL-49) reported being attacked by torpedoes just outside the harbor but they impacted a coral reef and exploded short of the ship. As of December 2003, I-16tou has not yet been located.
I-18tou, commanded by Shigemi Furuno and crewed by Shigenori Yokohama, was depth-charged outside the harbor in Keehi Lagoon. The wreck was accidentally discovered in July 1960 by Navy divers on a training dive. Being in fairly shallow water (78 feet), it was raised and inspected. No crew remains were found. Its bow (with its still-dangerous torpedoes) was cut off and resunk, and the rest of the boat shipped to Japan in 1961. There, a new bow was fabricated and the boat put on display on Eta Jima.
I-20tou, commanded by Akira Hiro-o and crewed by Yoshio Katayama, was ordered to attack from a location closer to Waikiki than any of the other ko-hyoteki. Near their assigned location and before the air attack on Pearl began, the destroyer USS Ward (DD-139) reported firing on a submarine. In late August 2002, research submersibles from the University of Hawaii discovered the wreck of a ko-hyoteki with a three-inch shell hole in its sail. That shell must have killed Hiro-o, making him the very first enemy killed by United States forces in World War II.
I-22tou managed to make it into the harbor and fired a torpedo at the Curtiss (AV-4) that missed. Curtiss opened fire with her #3 gun and observed a hit on the conning tower. Shortly thereafter, about 0840, I-22tou was rammed and depth-charged by the Monaghan (DD-354). The wreck was later raised and used as landfill in a hole already excavated for pier construction at Submarine Base Pearl Harbor with the bodies of commander Naoji Iwasa and crewman Naokicki Sasaki still aboard.
I-24tou (Ha-19) suffered mechanical problems and was captured the day after the attack. Its crewman, Kiyoshi Inagake, was killed, and its commander, Kazuo Sakamaki, was captured and made a prisoner of war -- the first for America. The sub was displayed throughout the United States and is currently at the National Museum of the Pacific War in Fredericksburg, Texas.
References
