Japanese submarine I-20 facts for kids
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The I-20 was a special kind of submarine used by the Imperial Japanese Navy during World War II. It was a "cruiser submarine" from the Type C1 class. These submarines were designed for long trips and could carry a small, special submarine called a midget submarine.
The I-20 played a part in important battles. It launched a midget submarine during the attack on Pearl Harbor in 1941 and another during an attack on Diego-Suarez in 1942. It also went on patrols in the Pacific Ocean and Indian Ocean. Later, it helped in the Guadalcanal campaign and New Guinea campaign by delivering supplies. The I-20 was last heard from on August 31, 1943.
Contents
History | |
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Name | Submarine No. 46 |
Builder | Mitsubishi Kobe Yard, Kobe |
Laid down | 16 November 1937 |
Renamed | I-20 |
Launched | 25 January 1939 |
Completed | 26 September 1940 |
Commissioned | 26 September 1940 |
Fate | Lost after 31 August 1943 |
Stricken | 1 December 1943 |
General characteristics | |
Class and type | Type C1 submarine |
Displacement |
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Length | 109.3 m (358 ft 7 in) overall |
Beam | 9.1 m (29 ft 10 in) |
Draft | 5.3 m (17 ft 5 in) |
Installed power |
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Propulsion |
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Speed |
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Range |
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Test depth | 100 m (330 ft) |
Crew | 95 |
Armament |
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Notes | Fitted to carry 1 × Type A midget submarine |
Design and Features
The Type C submarines, like the I-20, were built for long-distance attacks. They were quite large for submarines of their time. When on the surface, they weighed about 2,554 tons. When underwater, they weighed about 3,561 tons.
These submarines were about 109.3 meters (358 feet) long. They were 9.1 meters (29 feet 10 inches) wide and had a draft (how deep they sat in the water) of 5.3 meters (17 feet 5 inches). They could dive to a depth of 100 meters (328 feet).
Power and Speed
For moving on the surface, the I-20 used two powerful diesel engines. Each engine turned a propeller. When underwater, electric motors powered the propellers. This allowed them to reach speeds of 23.6 knots (about 43.7 km/h or 27.1 mph) on the surface and 8 knots (about 14.8 km/h or 9.2 mph) underwater.
The I-20 could travel very far. On the surface, it had a range of 14,000 nautical miles (about 25,900 km or 16,100 miles) at 16 knots. Underwater, its range was much shorter, about 60 nautical miles (110 km or 69 miles) at 3 knots.
Weapons and Special Equipment
The I-20 was well-armed. It had eight torpedo tubes at the front, which could fire 53.3 cm (21 inch) torpedoes. It carried a total of 20 torpedoes. On its deck, it had a large 140 mm (5.5 inch) gun. It also had two 25 mm anti-aircraft guns to defend against planes.
A unique feature of the I-20 was its ability to carry a Type A midget submarine. This small submarine was carried on the back of the main submarine, behind the conning tower (the part that sticks up).
The I-20 was ordered as part of a Japanese naval expansion plan. It was built by Mitsubishi in Kobe, Japan. Its keel (the bottom part of the ship's frame) was laid down on November 16, 1937. At first, it was called Submarine No. 46.
By the time it was launched on January 25, 1939, it had been renamed I-20. The submarine was officially finished and joined the navy on September 26, 1940.
Service History
Before World War II
After joining the navy, the I-20 was based at Yokosuka Naval District. In 1940, it helped test a German-made passive sonar system, which listens for sounds underwater. It became part of Submarine Division 2, along with I-18 and I-19.
In late 1941, the I-20 was changed so it could carry and launch a Type A midget submarine. Four other submarines, I-16, I-18, I-22, and I-24, also got this special conversion.
On November 17, 1941, the commanders of these five submarines learned about the upcoming attack on Pearl Harbor. Their job was to launch their midget submarines near Pearl Harbor to join the attack.
On November 18, 1941, each submarine took on a midget submarine. The next day, they left Japan and headed for the Hawaiian Islands. On December 2, 1941, they received a secret message, "Climb Mount Niitaka 1208," which meant war with the Allies would begin on December 8 (Japan time).
World War II
Pearl Harbor Attack
In the early morning of December 7, 1941, the I-20 launched its midget submarine, No. 17, south of Oahu, Hawaii. The American destroyer USS Ward (DD-139) spotted No. 17 and fired on it, hitting its conning tower. The Ward then dropped depth charges, and No. 17 sank outside Pearl Harbor, losing its two crew members. This was the first shot fired by American forces in World War II.
The I-20 and the other "mother" submarines waited for their midget submarines to return, but none did. The I-20 left Hawaii on December 12, 1941, and arrived back at Kwajalein Atoll on December 22, then went to Japan for maintenance.
First Patrol and Indian Ocean Operations
On January 4, 1942, the I-20 began its first war patrol near Fiji and the Samoan Islands. On January 11, it surfaced near Pago Pago in American Samoa and fired its deck gun at the naval station. Most shells missed, causing only minor injuries.
Later, on January 16, the I-20 tried to attack the New Zealand ship HMNZS Monowai near Suva, Fiji. Its torpedoes exploded too early. The I-20 surfaced to use its gun, but the Monowai fired back. Both ships were unharmed. The I-20 returned to Japan for repairs.
In April 1942, the I-20 was part of a special Japanese submarine group, the "A" detachment, sent to attack Allied ships in the Indian Ocean. This group also included midget submarines. On May 17, the I-20 had some trouble when seawater flooded its engine room twice, but the crew fixed it.
On May 30, 1942, the I-20 launched its midget submarine off Diego-Suarez, Madagascar. This midget submarine torpedoed the British battleship HMS Ramillies and sank the tanker British Loyalty. The midget submarine's crew later went ashore but were found and died in a fight with British forces.
After this, the I-20 joined other submarines in attacking Allied shipping. It sank several merchant ships in June 1942, including the Panamanian Johnstown, the Greek Christos Markettos, and the British Mahronda. It also sank the Panamanian Hellenic Trader and the British Clifton Hall.
On June 29, it sank the Norwegian ship Goviken. On June 30, it attacked the British tanker Steaua Romana with gunfire and torpedoes, sinking it. The I-20 then returned to Japan for a major overhaul, arriving on August 23, 1942.
Guadalcanal and New Guinea Campaigns
The Guadalcanal campaign began in August 1942. After its overhaul, the I-20 left Japan on October 24, 1942, to join the fighting. It was ordered to carry midget submarines to the Solomon Islands.
On November 5, the I-20 loaded midget submarine No. 11. It launched No. 11 off Guadalcanal on November 7. No. 11 hit the American ship USS Majaba (AG-43), damaging it so much that it had to be beached. The crew of No. 11 scuttled their submarine and swam to shore safely.
The I-20 continued to launch midget submarines off Guadalcanal in November and December 1942, but these attacks were not successful in sinking ships. The crews of these midget submarines also scuttled their vessels and swam to shore.
In late 1942 and early 1943, the I-20 was used for supply runs to Japanese forces on Guadalcanal. It delivered food and ammunition in rubber containers. It was also the first Japanese submarine to use a special submersible cargo container called an Unkato, which could carry a lot of supplies.
After the Guadalcanal campaign ended, the I-20 began supply runs to New Guinea in March 1943. It delivered food and ammunition to Lae and evacuated soldiers. On April 2, 1943, it had a minor underwater collision with its sister ship I-16 but was not badly damaged. It continued its supply missions, dropping off cargo and picking up soldiers at Lae and Kolombangara.
Final Patrol and Loss
After another overhaul, the I-20 left Japan on August 4, 1943, for its second war patrol in the New Hebrides. On August 30, it reported seeing an Allied force, including an aircraft carrier and battleships. On August 31, it reported that it had torpedoed and damaged the American tanker W. S. Rheem. This was the last time the I-20 was heard from.
The exact reason for the I-20's loss is not known. It was patrolling near the New Hebrides along with another Japanese submarine, I-182, and neither returned. American forces reported two successful anti-submarine attacks off Espiritu Santo in early September 1943. It is believed that one of these attacks sank the I-20 and the other sank the I-182.
On November 18, 1943, the Imperial Japanese Navy officially declared the I-20 lost with all 101 crew members. It was removed from the Navy list on December 1, 1943.