Kō-hyōteki-class submarine

carried ''Type 'C' No.69''. Fifty were built. The "A Target" name was assigned as a ruse: if their design were prematurely discovered by Japan's foes, the Japanese Navy could insist that the vessels were battle practice targets. They were also called or and other nicknames. The first two, No.1 and No.2, were used only in testing. They did not have conning towers, which were added to the later boats for stability under water. No.19 was launched by at Pearl Harbor. Most of the other 50 are unaccounted for, although three were captured in Sydney (Australia), and others in Guam, Guadalcanal, and Kiska Island, accounting for some of the other hull numbers. The submarines were each armed with two 450 mm (17.7 in.) torpedoes in muzzle-loading tubes one above the other at the bow. In the Pearl Harbor attack, the specially designed Type 97 torpedo was used, with a warhead and a range of at , but problems with the oxygen flasks which held the air for propulsion meant that all later attacks used a different torpedo. Some have stated that a version of the Type 91 torpedo, designed for aircraft launching, was used, but other reports indicate that the Type 97 torpedo was modified to the Type 98, otherwise known as the Type 97 special. There is no definitive information that the Type 91 was used. The Type 98 was later supplanted by the Type 02 torpedo. After the war 300 midget submarines of various types were found in various stockpiles in Japan. The submarines were fitted with 1300Ib warheads to be used in suicide attacks. They were intended to ram enemy ships in the event of a mainland invasion but were believed to have never been used. Each submarine had a crew of two men. A junior officer conned the boat while a petty officer manipulated valves and moved ballast to control trim and diving. ==Pearl Harbor attack==

Five of these boats participated in the Pearl Harbor attack, with possibly two actually making it into the harbor. Secret war records show that submarine crews had been ordered to scuttle their subs after the attack and provisions were made to recover stranded crews. Of the five used at Pearl Harbor, No.19 was captured with its pilot Kazuo Sakamaki where it grounded on the east side of Oʻahu. During World War II, No.19 was put on tour across the United States to help sell War Bonds. Now a U.S. National Historic Landmark, No.19 is an exhibit at the National Museum of the Pacific War in Fredericksburg, Texas. A fourth submarine, No.22, entered the harbor and fired its torpedoes at and . Both of those torpedoes missed and are believed to have hit a dock at Pearl City and the shore of Ford Island. Japanese forces received a radio message believed to be from the fifth submarine, No. 16 at 00:41 on 8 December claiming damage to one or more large warships inside Pearl Harbor. At 22:41 on 7 December, they received a message from No. 16 describing the air attack on Pearl Harbor as successful, and at 00:51 on 8 December they received another message that read "Unable to navigate." They never heard from No. 16 again. In 1992, 2000, and 2001, Hawaiʻi Undersea Research Laboratory's submersibles found the wreck of a midget sub lying in three parts three miles south of the Pearl Harbor entrance. The wreck was in the debris field where much surplus U.S. equipment was dumped from the West Loch Disaster of 1944, including vehicles and landing craft. In 2009, a research team assembled by the PBS television series Nova positively identified the sub as being the last, No.16, of the 5 Ko-Hyoteki that participated in the 7 December 1941, attack, piloted by Ensign Masaji Yokoyama and Petty Officer 2nd Class Sadamu Kamita. Both of its torpedoes were missing, indicating that the midget sub may have fired its torpedoes prior to its sinking. Although this correlates with reports of two torpedoes fired at the light cruiser at 10:04 at the entrance of Pearl Harbor, and a possible torpedo fired at destroyer at 08:21, there is dispute over this official chain of events; the "torpedo" that St. Louis saw was also reportedly a porpoising minesweeping float being towed by the destroyer . Some have suggested that circumstantial evidence supports a hypothesis that No.16 successfully entered Pearl, fired its torpedoes at Battleship Row, and fled to the relative quiet of neighboring West Loch, and possibly was scuttled by its crew. When a series of explosions sank an amphibious fleet being assembled in the Loch in 1944, it is suggested the remains of the sub were collected and dumped in the subsequent salvage operation, which was kept classified as secret until 1960. A photograph taken from a Japanese plane during the Pearl Harbor attack shows what might have been No.16 inside the harbor firing its torpedoes at Battleship Row. The photo was declassified in the 1990s and publicized in the 2000s to the public. The sinking of the USS West Virginia and capsizing of the may have been accelerated by a torpedo hit from a submarine-launched torpedo, the warheads of which were larger than the aerial torpedoes. Some believe that in the photo, where the torpedoes' paths had supposedly started, were sprays that indicated a midget-submarine rocking up and down due to the force of the torpedo being launched, causing the propellers of the stern to be exposed, kicking up clouds of water spray. A war time report from Admiral Nimitz confirmed the recovery of at least one dud torpedo of the type employed by the midget submarines. The theory is covered in the Nova episode Killer Subs in Pearl Harbor and companion website, I-16tou.com. ==Attacks on Sydney==

On the night of 29 May 1942, five large Japanese submarines positioned themselves 56 kilometres north-east of Sydney Heads. At 3 a.m. the next day one of the submarines launched a reconnaissance aircraft. After circling Sydney Harbour the aircraft returned to its submarine, reporting the presence of 'battleships and cruisers' moored in the harbour. The flotilla's commanding officer decided to attack the harbour with midget submarines the next night. The next day the five submarines approached to within 11 kilometres of Sydney Heads, and at about 4:30 p.m. they released three midget submarines, which then began their approach to Sydney Harbour. The outer-harbour defences detected the entry of the first midget submarine, No.14, at about 8 pm, but it was not identified until it became entangled in an anti-torpedo net that was suspended between George's Head and Green Point. Before HMAS Yarroma was able to open fire, the submarine's two crew members destroyed their vessel with demolition charges and killed themselves. The second submarine, No.24b, entered the harbour at about 9.48 p.m. and headed west towards the Sydney Harbour Bridge, causing a general alarm to be issued by the Naval Officer in Charge, Sydney. About 200 metres from Garden Island the submarine was fired on by the heavy cruiser . The submarine then fired its two torpedoes at the cruiser. One torpedo ran ashore on Garden Island, but failed to explode. The other passed under the Dutch submarine K9 and struck the harbour bed beneath the depot ship HMAS Kuttabul where it exploded, killing 21 sailors (19 Royal Australian Navy and 2 Royal Navy). The submarine then slipped out of the harbour, its mission complete, and disappeared. Its wreck was located, about 30 km north of the harbour and 5 km to seaward, in November 2006. It is now protected as a war grave. The third submarine, No.21, was sighted by HMAS Yandra at the entrance to the harbour and was depth-charged. Some four hours later, having recovered, it entered the harbour, but it was subsequently attacked with depth charges and sunk in Taylor Bay by vessels of the Royal Australian Navy. Both members of the submarine's crew committed suicide. The two submarines that were recovered were identical, and their remains were used to reconstruct a complete submarine, which toured New South Wales, Victoria and South Australia before being delivered to the Australian War Memorial in Canberra in 1943, where it remains on display. ==Attacks on Madagascar==

On 29 May 1942, the Japanese submarines I-10, I-16 and I-20 arrived at Madagascar. I-10s reconnaissance plane spotted Revenge-class battleship at anchor in Diego Suarez harbor but the plane was spotted and Ramillies changed her berth. I-20 and I-16 launched two midget submarines, one of which managed to enter the harbor and fired two torpedoes while under depth charge attack from two corvettes. One torpedo seriously damaged Ramillies, while the second sank the 6,993 ton oil tanker British Loyalty (later refloated). Ramillies was later repaired in Durban and Plymouth. The crew of one of the submarines, Lieutenant Saburo Akieda and Petty Officer Masami Takemoto, beached their submarine (No.20b) at Nosy Antalikely and moved inland towards their pick-up point near Cape Amber. They were informed upon when they bought food at a village and both were killed in a firefight with Royal Marines three days later. The second midget submarine, No.16b, was lost at sea and the body of one of its crew was found washed ashore a day later. ==Characteristics==

There are the remains of one in the open at Kiska in the Aleutian Islands, and some in the waters nearby. There are four reasonably intact Type A midgets on display in the world: • HA-8 – Submarine Force Library and Museum, Groton, Connecticut • HA-18 – JMSDF Etajima Naval Base, Etajima, Japan • HA-19 – National Museum of the Pacific War, Fredericksburg, Texas • A composite of two that entered the Sydney harbor in May 1942 – Australian War Memorial, Canberra, Australia A third such submarine used in the attack at Sydney has been found, but remains in the waters off Sydney, to be left in situ as a war grave. Type C • HA. 62-76 - War in the Pacific National Historic Park, Nimitz Hill, Guam, U.S.A. On display in front of the T. Stell Newman Visitor Center. Thought to be the last remaining Type C midget submarine in existence. The submarine was listed on the National Register of Historic Places in 1999. ==References==