Imperial Submarines

SENSUIKAN!

HIJMS Submarine I-7: Tabular Record of Movement

© 2001 Bob Hackett & Sander Kingsepp

31 March 1937:
The I-7 is completed at the Kure Navy Yard, commissioned in the IJN and assigned to the Yokosuka Naval Disctrict.
15 November 1940:
Assigned to SubRon 2, Sixth Fleet.
10 November 1941: Operation "Z":
Saeki Bay. The I-7 is in Vice Admiral Shimizu Mitsumi's (former CO of ISE) Sixth Fleet as the flagship of Rear Admiral (later Vice Admiral) Yamazaki Shigeaki's (former CO of old CA YAKUMO) SubRon 2. The I-7 is in SubDiv 8 with the I-4, -5 and the I-6. LtCdr Koizumi Kiichi is the I-7's Commanding Officer.
Admiral Shimizu convenes a meeting of all his commanders aboard the Sixth Fleet's flagship, the light cruiser KATORI. LtCdr Koizumi and the other commanders are briefed on the planned attack on Pearl Harbor.
16 November 1941:
SubRon 2's submarines depart Yokosuka for Hawaii, but the I-7's departure is delayed for repairs.
21 November 1941:
The I-7, with Rear Admiral Yamazaki embarked, departs Yokosuka on her first war patrol.
2 December 1941:
The I-7 is located 300 miles N of Oahu whrn she receives the coded signal "Niitakayama nobore (Climb Mt. Niitaka) 1208" is received from the Combined Fleet. It signifies that hostilities will commence on 8 December (Japan time). Mt. Niitaka, located in Formosa (now Taiwan), is then the highest point in the Japanese Empire.
7 December 1941: The Attack on Pearl Harbor:
Off Hawaii. SubRon 2 is arrayed to the northeast and northwest of Oahu. Its mission is to reconnoiter and attack any ships that try to sortie from Pearl Harbor. The I-7 is the flagship for the subs stationed N of Oahu.
10 December 1941:
Kauai Channel, SE of Pearl Harbor. An enemy aircraft carrier and two cruisers are reported heading NE. Vice Admiral Shimizu at Kwajalein orders all of SubRon 1's boats, except the Special Attack Force, to pursue and sink the carrier.
In the evening, LtCdr Koizumi receives an order from the flagship KATORI to conduct a recce flight over Pearl Harbor.
17 December 1941:
Early in the morning, the I-7 launches her Watanabe E9W1 "Slim" floatplane to conduct a battle-damage assessment over Pearl. The Japanese operational plan provides that if the American Fleet is destroyed, one SubDiv will be positioned to interdict traffic between Hawaii and North America. The floatplane lands next to the I-7. The pilot abandons the plane and swims to the submarine. Once aboard, the I-7 crash dives. The pilot reports seeing four battleships, including three that are damaged, and an aircraft carrier. He also counts five cruisers and 30 smaller vessels, including three destroyers patrolling off the harbor's entrance.
2 January 1942:
After nightfall, LtCdr Koizumi sights several destroyers heading for Pearl. He initiates a torpedo attack, but misses. In turn, the destroyers drop six depth charges, but they fail to cause any damage.
9 January 1942:
270 miles from Johnston Island. The I-18 reports sighting a carrier, a heavy cruiser and two destroyers steaming westward. Rear Admiral Yamazaki orders the I-5 and -6 to intercept the carrier, but they make no contact.
10 January 1942:
300 miles from Johnston Island. The I-18 reports sighting two SBD "Dauntless" dive-bombers flying west. LtCdr Koizumi realizes that there must be a carrier within 200 miles. Admiral Yamazaki sends the I-1, 2, -3, -5, -6 and the I-7 to form a patrol line to intercept it.
13 January 1942:
Admiral Yamazaki orders SubRon 2 to terminate the patrol off Hawaii.
20-22 January 1942:
SubRon 2 returns to Kwajalein.
24 January 1942:
Departs Kwajalein.
1 February 1942:
Arrives at Yokosuka.
5 February 1942:
SubRon 2's I-1 through the I-7 are assigned to Vice Admiral Takahashi Ibo's (former CO of KIRISHIMA) Dutch East Indies Invasion Force in Rear Admiral (later Vice Admiral) Ichioka Hisashi's (former CO of CL YURA) SubRon 2.
11 February 1942:
After SubRon 2's boats complete a refit and overhaul, they depart Yokosuka for Staring Bay off Kendari, Celebes in the Dutch East Indies.
22 February 1942:
The I-7 departs Staring Bay, with Rear Admiral Ichioka embarked, on her second patrol to operate in the Indian Ocean.
March 1942:
The I-7 makes port at Penang, Occupied Malaya.*
16 March 1942:
Vice Admiral, the Marquis, Komatsu Teruhisa (former CO of CA NACHI) assumes command of the Sixth Fleet (Submarines). Vice Admiral Shimizu is later reassigned as the CINC, First Fleet.
28 March 1942: Operation "C":
Headquarters, Combined Fleet orders that the western coast of India and Ceylon be reconnoitered before the commencement of Operation C. All of SubRon 2's boats, except the I-1, are to participate in the operation. The I-7 departs Penang for the Indian Ocean carrying an E14Y1 "Glen" floatplane.
1 April 1942:
The I-7 is ordered to perform aerial reconnaissance of Columbo and Trincomalee, Ceylon prior to attacks by Vice Admiral Nagumo Chuichi's Carrier Striking Force ("Kido Butai"). 180 ms SE of Ceylon. At 0817 (I), the I-7, while on the surface recharging her batteries, is suddenly attacked by a PBY "Catalina" of RCAF No. 413 Squadron. It drops two bombs, but both are duds. Four hours later, several small patrol vessels are sighted. LtCdr Koizumi decides that the area is too heavily patrolled. He cancels a reconnaissance flight scheduled for 3 April because the launch area seems compromised, but the I-7 does act as a weather ship.
3 April 1942:
Indian Ocean. 300 miles E of the Maldive Islands. At 0740 (I), the I-7 attacks the 9,415-ton British merchant GLENSHIEL. She fires two Type 95 torpedoes. One hits the GLENSHIEL's port side. The GLENSHIEL is abandoned by her crew. LCdr tKoizumi fires two more torpedoes and gets another hit. The submarine surfaces and her twin 140-mm. deck guns open fire. After 20 hits, the blazing GLENSHIEL sinks by the stern.
5 April 1942: Operation "C" - The Raids in the Indian Ocean:
The Carrier Striking Force attacks the British naval base on Columbo, Ceylon (now Sri Lanka), wreck the base's facilities, destroy 27 aircraft and sink several ships. A floatplane finds Vice Admiral James Somerville's Eastern Fleet's cruisers HMS CORNWALL and the DORSETSHIRE at sea. Nagumo's airmen sink both ships, but are unsuccessful in their search for the rest of Somerville's fleet.
9 April 1942:
Nagumo's Striking Force attacks the British naval base at Trincomalee, Ceylon. They wreck the base's facilities and shoot down nine planes. A floatplane spots the old light carrier HMS HERMES and the Australian destroyer HMAS VAMPIRE at sea and the Striking Force sinks both. Nagumo's aircraft also find and sink several smaller ships.
15 April 1942:
The I-7 and I-3 arrive at Singapore.
1 May 1942:
Arrives at Yokosuka for repairs and upkeep.
5 June 1942: Operation "AL"- The Invasion of the Western Aleutians:
Twenty ships of the Vice Admiral Hosogaya Boshiro's (former CO of MUTSU) Fifth Fleet, including the light cruisers KISO and the TAMA, three destroyers, three corvettes, three minesweepers and four transports land Rear Admiral (later Vice Admiral) Omori Sentaro's Occupation Force on Attu, Aleutians without opposition.
7 June 1942:
Captain (later Rear Admiral) Ono Takeji's Occupation Force occupies Kiska, also without opposition.
10 June 1942:
SubRon 2 is assigned to support operations in the Aleutians.
11 June 1942:
The I-7 departs Taura Bay, Yokosuka for the Aleutians on her her third patrol with the I-1, -2, -3 and -4.
20 June 1942:
The I-7 is in Rear Admiral Ichioka's SubRon 2 with the I-1 through the I-6.
14 July 1942:
N of Unalaska, Aleutians. LtCdr Koizumi torpedoes and shells the 2,722-ton American merchant ARCATA that is steaming from Bethel, Alaska to Seattle, Washington. The sea is choppy and the I-7's gun crew has trouble hitting the ship. Once the ARCATA's bridge is burning, the crew and the passengers abandon ship and the I-7 machine-guns it. The submarine ceases firing after they spot life rafts, but not before a merchant sailor is killed. The ARCATA sinks at 53-41N, 157-45W.
20 July 1942:
SubRon 2 is ordered to return to Japan, except the I-6 is ordered to remain at Kiska.
1 August 1942:
Arrives at Yokosuka for an overhaul.
7 August 1942: American Operation "Watchtower" - The Invasion of Guadalcanal, British Solomon Islands:
Rear Admiral (later Admiral) Richmond K. Turner's Amphibious Task Force 62, covered by Vice Admiral (later Admiral) Frank J. Fletcher's Task Force 61 and Rear Admiral (later Admiral) John S. McCain's Task Force 63's land-based aircraft, lands Maj Gen (later Gen/Commandant) Alexander A. Vandegrift's 1st Marine Division on Guadalcanal opening a seven-month campaign to take the island.
Prior to the American landing on Guadalcanal, the Sixth Fleet intended to send SubRon 2 into the Indian Ocean.
20 August 1942:
SubRon 2 is disbanded. The I-7 is directly subordinated to the Sixth Fleet.
8 September 1942:
Departs Yokosuka for the Solomons with Capt Tamaki Tomejiro (ComSubDiv 7) embarked on her fourth war patrol, carrying an E14Y1 "Glen" seaplane.
13 October 1942:
The I-7's floatplane reconnoiters Espiritu Santo. The pilot reports seeing two light cruisers, several destroyers and seven colliers off the south coast of Espiritu Santo.
14 October 1942:
After nightfall, the I-7 shells Espiritu Santo. She fires 17 shells.
23 October 1942:
Before dawn, the I-7 again shells Espiritu Santo. She fires six shells and dives to escape return fire.
31 October 1942:
The I-7 is ordered to conduct another recce flight over Espiritu Santo, but her aircraft is damaged and she is unable to launch it.
7 November 1942:
The I-7 carries out a periscopic observation of Espiritu Santo. She is relieved by the I-9 carrying a "Glen".
9 November 1942:
LtCdr Koizumi receives an order to reconnoiter Ndeni and Vanikoro on the way back to Truk.
10 November 1942:
LtCdr Koizumi carries out a periscopic observation of Ndeni. No important targets are sighted.
11 November 1942:
After repairs, the I-7's floatplane reconnoiters Vaniko island, Santa Cruz, Solomons.
1 December 1942:
Arrives at Yokosuka.
5 December 1942:
LtCdr Koizumi is relieved by LtCdr Tabata Naoshi.
15 March 1943:
LtCdr Nagai Katsuhiko (former CO of I-174) is assigned as the Commanding Officer. LtCdr Tabata is reassigned as the Commanding Officer of the I-175.
21 April 1943:
The I-7 is in SubRon 1 with the I-2, -5 and the I-6 in Captain Tamaki Tomejiro's SubDiv 7. She is assigned, with other submarines in the Northern District Force, Fifth Fleet, to reinforce and resupply the isolated Japanese garrisons in the Aleutian Islands. The I-7 departs Yokosuka for Kiska Island, Aleutians carrying food and ammunition.
1 May 1943:
Arrives at Kiska.
11 May 1943: American Operation "Sandcrab"- The Invasion of Attu, Aleutians: Rear Admiral (later Admiral) Thomas C. Kinkaid's Task Force 16, covered by Rear Admiral Francis W. Rockwell's Task Force 51, lands elements of the Army's 4th and 7th Infantry Divisions under the command of MajGen Eugene M. Landrum at Holtz Bay and Massacre Bay that later capture the island.
14 May 1943:
Departs Yokosuka with ComSubDiv 7 Captain Tamaki Tomejiro embarked on her fifth war patrol.
21 May 1943: Operation "KE-Go" - The Evacuation of Kiska:
The Imperial General Headquarters decides to abandon Attu and evacuate the garrison at Kiska.
22 May 1943:
The I-7 arrives at her assigned area off Attu.
25 May 1943:
The I-7 is ordered to return to participate in supply/evacuation missions to Kiska.
26 May 1943:
The evacuation via submarines from Kiska to Paramushiro Island, Kuriles begins. When the I-7 arrives at Kiska, it is under air attack so LtCdr Nagai decides to wait outside the harbor.
27 May 1943:
At 0630(I), the I-7 enters the harbor. She delivers food, ammunition and a radio beacon. For her return voyage, she embarks 49 sailors, seven soldiers and four construction workers, mostly sick and wounded, plus 28 boxes of the ashes of soldiers KIA and four tons of spent shell cartridges. The I-7 is the first and the last IJN submarine to visit Kiska, making a total of three runs.
9 June 1943:
The I-7 and I-34 arrive at Kiska, The I-7 carries 19 tons of ammunition and 15 tons of food. The I-7 successfully evacuates 101 men (42 navy, 18 army and 41 civilian workers) from Kiska.
15 June 1943:
Departs Paramushiro, with ComSubDiv 7 embarked, with ammunition and food for the Kiska garrison.
17 June 1943:
Radar-equipped American destroyer attacks on IJN submarines in the Aleutians area and the grounding of the I-175 cause ComSubRon 1 to order the I-7, -34, -36 and -169 to suspend their supply missions and await further orders. The I-2, -157 and the I-175 are tasked to determine the exact location of the American ships.
18 June 1943:
ComSubRom 1 orders the resumption of the supply missions to Kiska.
20 June 1943:
The I-7 makes a landfall off Kiska, but LtCdr Nagai decides not to enter Gertrude (Tanabata) Cove in Vega Bay because of a dense fog. He contacts the 51st Base Unit on Kiska and learns that the radio beacon will be deactivated after 0100, 21 June.
21 June 1943:
At 1330 (I), the I-7 surfaces in a heavy fog and proceeds towards the anchorage at Gertude Cove. LtCdr P. H. Horn's patrolling USS MONAGHAN (DD-354) picks up the I-7 on her SG radar at 13,000 meters and tracks it until about 1400. One mile S of the anchorage, she opens radar-directed fire. The shelling comes in from the starboard side of the I-7 and lasts about 10 minutes. The I-7 takes two 5-inch direct hits that rip her decks and devastate the conning tower. LtCdr Nagai, Captain Tamaki, Navigator Lt Hanabusa Yoshio and three other crewmen are killed and the communications officer is wounded. The pressure hull is penetrated in the conning tower area and the main ballast tanks are holed. The I-7 fires back with her 13.2 mm machine guns. The damage to the I-7 is such that she is unable to submerge. The Exective Officer, Lt Sekiguchi Rokuro takes command. At 1515, he runs the I-7 aground at Bukhti (Asahi) Point.
Earlier, the 51th Base Force sent a Daihatsu barge to unload the I-7's cargo. The Daihatsu, sailing in the thick fog, tries to contact the I-7 using a blinker gun. Instead, she receives a hail of machine gun bullets from the MONAGHAN that had spotted this new target 40 minutes after her last shot at the I-7. The barge doubles back, informs HQ of the I-7's grounding and then returns to the submarine. She takes aboard an officer from the I-7 who coordinates the unloading efforts.
22 June 1943:
By 0300 (I), with the help of a group of IJA soldiers, the I-7's cargo is unloaded at Hita Bay. During that time, the water is pumped out. By 1445, the I-7 is refloated and moved to the entrance of Gertrude Cove. By 1830, emergency repairs are completed but the submarine is still unable to submerge. After a brief discussion Lt Sekiguchi decides to return to Paramushiro on the surface since the I-7's speed is not impaired.
At 2000, the I-7 starts back to Yokosuka. She makes only about 10 miles when at 2125 she is suddenly attacked by no less than three vessels from all forward quadrants. In the next few minutes, she takes more hits in the conning tower while firing back from her guns and machine guns. The acting CO Lt Sekiguchi, Engineering Officer Lt Handa Masao and Lt (j.g.) Mori Yoshisaburo are killed as are many crewmen. The submarine makes a U-turn at full speed. During this second engagement, the I-7 fires 70 of her main caliber shells and about 1,000 machine-gun rounds.
The Chief Gunnery Officer, Lt (j.g.) Shindo Yoshio assumes command and cons the submarine from her wrecked conning tower. The I-7's lookouts spot what they take to be a small fire on one of the attackers. For a while it is thought that the enemy has lost contact, but star shells are sighted and the Japanese sailors decide there is no way to escape.
At 2300, Shindo runs the I-7 aground on the Twin (Futagoiwa) rocks. Fifty feet (15 meters) of the bow protrude out of the water and she develops a heavy list to port. The I-7's stern remains intact in only 100 feet of water. Forty-three survivors (including 10 wounded) are evacuated by another Daihatsu.
23 June 1943:
S of Kiska Harbor. The I-7 is abandoned at Vega Bay at 51-49N, 177- 20E. Eighty-seven officers and crewmen are killed. A bag containing code books and other secret documents is left suspended on a ladder at her No. 3 after access hatch, but her crew makes no attempts to scuttle her.
24 June 1943:
A Daihatsu from Kiska scuttles the bow of the I-7 in the midst of the fog, using demolition charges. The crew attempts to locate the code books prior to the scuttling, but fails to retreive them. The explosion breaks the hull of the submarine into two parts. Captain Tamaki is promoted Rear Admiral, posthumously and LtCdr Nagai is promoted Commander, posthumously.
20 August 1943:
Removed from the Navy List.
26 August 1943:
The fleet tug USS UTE (ATF-76) is sent to investigate the reported sinking. Her divers find the submarine lying on her port side in 10 fathoms of water. The conning tower is damaged but the I-7's hull number is visible on a tarp on the side of the conning tower.
7 September 1943:
The submarine rescue ship USS FLORIKAN (ASR-9) arrives at Kiska from Midway. She carries out a month-long diving operation on the I-7's hulk. Seven divers enter the submarine and recover important intelligence documents.

Authors' Notes:
* The I-7 reports that on 4 March 1942, she shelled and sank a ship at 08S, 95E. Some sources claim this ship was the 3,271-ton Dutch passenger ship Le MAIRE, but this claim has been challenged by some Dutch sources. The ship may have been the 865-ton MERKUS that was sunk in the same area (08-40S, 94-30E) and was heavily shelled until her crew abandoned her.
Special thanks for help in preparing this TROM go to Dr. Higuchi Tatsuhiro of Japan and Jan Visser ("Visje") of the Netherlands. - Bob Hackett and Sander Kingsepp.

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