Japanese submarine I-7 facts for kids
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|} I-7 was a large submarine built for the Imperial Japanese Navy and launched in 1937. It was a "J3 type" cruiser submarine, meaning it was designed to travel long distances and carry a small seaplane. I-7 served during World War II. It helped with the attack on Pearl Harbor, patrolled the Indian Ocean, and took part in battles like the Guadalcanal campaign and the Aleutian Islands campaign. In June 1943, I-7 was badly damaged in a fight with the American destroyer USS Monaghan (DD-354) and eventually sank near the Aleutian Islands.
Contents
- Before World War II
- First War Patrol: Pearl Harbor Support
- Second War Patrol: Indian Ocean
- Indian Ocean Raid
- Third War Patrol: Aleutian Islands
- Fourth War Patrol: Guadalcanal
- Supplying Kiska in the Aleutians
| History | |
|---|---|
 Imperial Japanese Navy |
|
| Name | I-7 |
| Ordered | 1934 |
| Builder | Kure Naval Arsenal, Kure, Japan |
| Laid down | 12 September 1934 |
| Launched | 3 July 1935 |
| Completed | 31 March 1937 |
| Commissioned | 31 March 1937 |
| Fate | Wrecked 22 June 1943 |
| Stricken | 20 August 1943 |
| General characteristics | |
| Class and type | J3 type submarine |
| Displacement |
|
| Length | 109.30 m (358 ft 7 in) |
| Beam | 9.10 m (29 ft 10 in) |
| Draft | 5.26 m (17 ft 3 in) |
| Depth | 7.70 m (25 ft 3 in) |
| Propulsion |
|
| Speed |
|
| Range |
|
| Test depth | 100 m (328 ft) |
| Complement | 100 officers and men |
| Armament |
|
| Aircraft carried | 1 x Watanabe E9W1 |
| Aviation facilities | Hangar, catapult |
Building and Launching I-7
I-7 was the first of two "Junsen III" type submarines. These submarines were designed to be flagships for submarine squadrons, meaning they would lead groups of submarines. They combined the best features of earlier Japanese submarines.
I-7 and its sister ship, I-8, were special because they could carry a floatplane (a small airplane that lands on water). They had a hangar (a storage area) and a catapult to launch the plane. This allowed them to do reconnaissance (scouting) missions.
The I-7 was built by the Kure Naval Arsenal in Kure, Japan. Its construction started on September 12, 1934. It was launched into the water on July 3, 1935, and officially joined the navy on March 31, 1937.
I-7's Early Service
Before World War II
When I-7 joined the navy, it was based in the Yokosuka Naval District. It quickly became an important ship, serving as the flagship (leading ship) for different submarine squadrons within the Imperial Japanese Navy's Combined Fleet.
In October 1940, I-7 took part in a huge fleet review in Yokohama Bay. This was the largest fleet review in Japanese history, celebrating an important anniversary for Japan.
On October 21, 1941, while doing training exercises, I-7 accidentally bumped into another submarine, I-66. Both ships only had minor damage.
In November 1941, the commander of the 6th Fleet, Vice Admiral Mitsumi Shimizu, told his submarine commanders about the upcoming attack on Pearl Harbor. This attack would start World War II for Japan and the United States. I-7 was then assigned to the Submarine Advance Force.
First War Patrol: Pearl Harbor Support
As the war began, I-7 sailed towards the Hawaiian Islands with its floatplane on board. On December 2, 1941, it received a secret message, "Climb Mount Niitaka 1208," which meant the war would begin on December 8 (Japan time).
On December 7, 1941, the day of the attack on Pearl Harbor, I-7 and other submarines patrolled the Pacific Ocean near Oahu. Their job was to scout the area and attack any ships leaving Pearl Harbor.
On December 16, 1941, I-7 launched its floatplane to fly over Pearl Harbor. The plane reported on the damage from the attack, seeing battleships, an aircraft carrier, and many other ships. After the flight, the plane landed near I-7, and its crew swam to the submarine. I-7 then sank the plane and left the area.
Later, I-7 moved to patrol southwest of Oahu. On January 1, 1942, it saw a cruiser and two destroyers heading for Pearl Harbor. I-7 fired two torpedoes, but they missed. The destroyers dropped depth charges, but I-7 was not hit. It then went to Kwajalein and later returned to Yokosuka.
Second War Patrol: Indian Ocean
In February 1942, I-7 was sent to the Dutch East Indies (now Indonesia) to help with the invasion there. It then started its second war patrol in the Indian Ocean, south of Java. Its mission was to stop Allied ships traveling between Java and Australia.
On March 4, 1942, I-7 surfaced in the Indian Ocean and used its deck guns to attack the Dutch merchant ship Merkus. The Merkus was carrying rubber from Java to Ceylon. Its crew safely left the ship. I-7 then sank the Merkus with more gunfire. After this, I-7 ended its patrol at Penang in Japanese-occupied British Malaya.
Indian Ocean Raid
I-7 was then ordered to scout the coasts of Ceylon and India for a big Japanese attack called the Indian Ocean raid. On March 28, 1942, I-7 left Penang with its floatplane. Its job was to scout Colombo and Trincomalee in Ceylon before the Japanese aircraft carriers attacked.
On April 1, 1942, a British flying boat attacked I-7 in the Indian Ocean, but I-7 was not damaged. Because there were many enemy ships around, I-7's commander decided not to launch the reconnaissance flight. Instead, I-7 sent weather reports to the approaching Japanese fleet.
On April 3, 1942, I-7 attacked the British ship Glenshiel in the Indian Ocean. I-7 fired torpedoes, hitting the Glenshiel, which was carrying passengers and cargo. The crew and passengers abandoned the ship safely. I-7 then fired more torpedoes and used its deck guns to sink the burning Glenshiel.
After this, I-7 went to Singapore and then returned to Yokosuka for repairs.
Third War Patrol: Aleutian Islands
While I-7 was being repaired, the Aleutian Islands campaign began in June 1942. Japanese forces attacked Dutch Harbor in Alaska and occupied Attu and Kiska. I-7 was sent to the Aleutians for its third war patrol.
On July 14, 1942, in the Gulf of Alaska, I-7 torpedoed the American transport ship Arcata. The Arcata was traveling from Alaska to Seattle. I-7 then attacked Arcata with gunfire. After one of I-7's shells hit Arcatas bridge, its passengers and crew left the ship. Seven of Arcatas crew members died. The Arcata then sank.
I-7 finished its patrol and returned to Yokosuka for maintenance.
Fourth War Patrol: Guadalcanal
In August 1942, the Guadalcanal campaign began in the Solomon Islands. I-7 was sent to the area. On September 19, 1942, it began its fourth war patrol southeast of San Cristobal.
On October 10, 1942, I-7 was ordered to scout Espiritu Santo (an island in Vanuatu). On October 13, its floatplane flew over Espiritu Santo and reported seeing several ships. On October 14, after dark, I-7 fired fourteen shells at Espiritu Santo. It bombarded the island again on October 23, but had to stop when coastal guns fired back.
I-7 continued its scouting missions, checking other islands like Ndeni and Vanikoro in the Santa Cruz Islands. It then returned to Truk and later to Yokosuka for a long stay.
Supplying Kiska in the Aleutians
In April 1943, I-7 was sent back to the North Pacific to deliver supplies and reinforcements to Japanese soldiers stuck on Attu and Kiska in the Aleutian Islands. On April 21, 1943, I-7 left Yokosuka with food and ammunition for Kiska. It delivered the cargo to Kiska and then to Attu.
While I-7 was sailing, American forces landed on Attu, starting the Battle of Attu. The Japanese decided to abandon Attu and evacuate their soldiers from Kiska by submarine.
On May 26, 1943, I-7 arrived off Kiska, but the harbor was under air attack. It waited, then entered the harbor to unload food, ammunition, and a radio beacon. It then took on 60 sick and wounded passengers, as well as the remains of soldiers, and sailed back to Paramushiro.
I-7 made another supply run to Kiska on June 4, 1943. It unloaded more supplies and took on 101 passengers, returning to Paramushiro on June 13.
I-7 left Paramushiro again on June 15, 1943, for another supply mission. However, due to recent attacks on Japanese submarines by American destroyers with radar, I-7 and other submarines were told to wait for new orders. Despite this, the supply runs were soon ordered to continue. On June 19, I-7 arrived off Kiska, but thick fog made it hard to enter the harbor.
The Loss of I-7
On June 20, 1943, I-7 surfaced near Kiska in heavy fog, trying to enter Gertrude Cove. The American destroyer USS Monaghan (DD-354) detected I-7 on its radar. I-7 did not have radar and only heard Monaghan's propellers shortly before the destroyer opened fire.
Monaghan hit I-7's conning tower (the control center) twice, killing several officers, including I-7s commander. The submarine was badly damaged and began to flood. I-7s torpedo officer took command and ordered the crew to fight back with their deck guns and machine guns. I-7 then ran aground (got stuck) at Bukhti Point. The crew abandoned ship, and secret documents were destroyed.
Japanese landing crafts came to help, taking some cargo and trying to patch the hole in I-7's conning tower. After repairs, I-7 entered Gertrude Cove, unloaded more cargo, and took on new code books. It left Kiska at midnight on June 21/22, 1943.
Monaghan detected I-7 again on radar early on June 22. It opened fire, hitting I-7 several times. I-7s steering was disabled, and a fire started. The submarine took on a severe list. With heavy casualties, I-7s acting commander ordered it to return to Kiska. Monaghan stopped its pursuit to avoid running aground itself.
I-7 was in danger of sinking. At 3:15 AM, it ran aground on the Twin Rocks off Vega Bay. It sank quickly by the stern, trapping some men inside. The front part of its hull remained out of the water. Eighty-seven officers and men were killed in the battle or when the submarine sank. A Japanese landing craft rescued the 43 survivors.
On June 23, divers tried to get the codebooks from I-7s wreck but couldn't find them. Demolition charges were then used to destroy the front part of I-7s hull. I-7 was officially removed from the Navy list on August 20, 1943.
After the Sinking
The Japanese successfully evacuated Kiska on July 28, 1943. On August 15, 1943, Allied forces invaded the island, finding it undefended.
On August 26, 1943, the American fleet tug USS Ute (ATF-76) arrived to investigate I-7s wreck. Divers found I-7 lying on its side in 60 feet (18 m) of water. Even though the conning tower was damaged, I-7s number could still be seen.
Starting on September 7, 1943, the American submarine rescue ship USS Florikan (ASR-9) spent a month diving on the wreck. Divers entered I-7 and recovered important intelligence documents.
