SENSUIKAN!

© 2001-2017 Bob Hackett & Sander Kingsepp
Revision 7

26 December 1942:
Yokosuka Navy Yard. Laid down as a Type B3 Submarine No. 631 (the last unit of that class). To make room for four kaiten human-torpedoes (only two are initially fitted with access tubes), the aft deck gun is not fitted. A Type 22 surface/air-search radar is installed atop the aircraft hangar and an E27/Type 3 radar detector on the bridge.

31 July 1943:
Re-numbered I-58 and provisionally attached to Kure Naval District.

9 October 1943:
Launched.

7 June 1944:
LtCdr Hashimoto Mochitsura (59)(former CO of RO-44) is appointed the Chief Equipping Officer (CEO).

7 September 1944:
Completed. Assigned to the Sixth Fleet's SubRon 11 for training. LtCdr (promoted Cdr 5 September 1945) Hashimoto Mochitsura is the Commanding Officer.

September-December 1944:
Inland Sea. I-58 works up with SubRon 11.

2 December 1944:
A special conference of more than 200 staff officers and specialists is held aboard the Sixth Fleet's flagship, TSUKUSHI MARU at Kure to evaluate the results of the first kaiten mission to Ulithi by the "KIKUSUI" (Floating Chrysanthemum) Group. Based on action reports and photo reconnaissance, the staff erroneously concludes that three aircraft carriers and two battleships were sunk in the attack.

4 December 1944:
Reassigned to SubDiv 15 in Vice Admiral Miwa Shigeyoshi's (former CO of CL KINU) Sixth Fleet.

8 December 1944:
Assigned to the "KONGO" (Steel) group with I-36, I-47, I-48, I-53 and I-56. The group is tasked with penetrating five different US fleet anchorages and launching kaiten attacks there. I-58 is tasked to attack Apra harbor, Guam on 11 January 1945.

19 December 1944:
Transferred to Otsujima to carry out kaiten launch exercises until 24 December.

December 1944:
Departs Sasebo for Kure to take on fuel, provisions and torpedoes.

29 December 1944: The Second Kaiten Mission:
Departs Kure for Otsujima.

30 December 1944:
Embarks four kaiten and their crews at Otsujima, then departs at 1000 in company of I-36, flying the "Hi-Ri-Ho-Ken-Ten" banner. [1]

6 January 1945:
Arrives in an area W of Guam. At 0200, when recharging batteries, I-58's radar detects a large flying boat.

9 January 1945:
A Nakajima C6N1 Saiun Myrt reconnaissance plane reports the presence of one escort carrier, two destroyers, one submarine, 20 transports and four floating docks at Apra harbor.

11 January 1945:
Arrives 26 miles SW of Guam. LtCdr Hashimoto approaches Apra harbor to launch his kaiten. Around 2100, he sights a large unescorted transport.

12 January 1945:
11 miles W of Apra. Between 0310 and 0327, I-58 launches all four kaiten. No. 3, launched after an engine malfunction as the last one, explodes immediately thereafter, preventing Hashimoto from observing the results of the attack. At 0530, when I-58 is leaving the area, two pillars of smoke are sighted

20 January 1945:
At night while approaching Bungo Suido Strait, I-58 picks up a submarine on her Type 22 radar. The submarine is later identified as I-36.

22 January 1945:
Arrives at Kure. I-58 is credited with sinking one escort carrier and one large oiler.

19 February 1945: American Operation "DETACHMENT" - The Invasion of Iwo-Jima:
Vice Admiral (later Admiral) Raymond A. Spruance's Fifth Fleet of over 450 ships, lands the 54th Amphibious Corps (3rd, 4th, 5th Marine Divisions) who capture the island and its vital Motoyama airfields from LtGen Kuribayashi Tadamichi's defenders.

Late February 1945:
A Type 13 air-search radar is installed.

28 February 1945: The Fourth Kaiten Mission:
I-58 and I-36 are in the "SHIMBU" unit formed to attack American American communications to Iwo Jima.

1 March 1945:
Departs Hikari, carrying four kaiten. At 2100, exits the Bungo Strait.

3-4 March 1945:
Incoming American planes are spotted with I-58's Type 13 radar. I-58 manages to crash-dive each time.

7 March 1945:
N of Iwo Jima. I-58 surfaces to recharge her batteries. Hashimoto plans to release all four of his kaiten the next morning to attack anchored shipping off Iwo. Later that day a signal is received from the Combined Fleet that directs the Sixth Fleet to cease operations in the Iwo Jima area.

9 March 1945:
I-58 is redirected to the area W of Okino-Torishima (Douglas Reef) to participate in Operation "TAN No. 2." Hashimoto jettisons two kaiten and proceeds at full speed towards Okino-Torishima. [2]

10 March 1945: Operation TAN No. 2 - The Kamikaze Raid on Ulithi:
Kyushu. Twenty-four Yokosuka P1Y Ginga (Milky Way) "Frances" twin-engine bombers take off from Kanoya airfield on a one-way "tokko" (suicide) mission to attack American carriers at the Third Fleet's anchorage at Ulithi. The bombers, originally of the 762nd NAG, were formed into the "Azusa Tokkotai" kamikaze unit and are led by two Kawanishi H8K Emily pathfinders of the 801st NAG. Each "Frances" carries a single 800-kg bomb.

11 March 1945:
I-58 takes up station off Okino-Torishima and functions as a radio relay ship for the "Frances" bombers. Only six reach Ulithi. They drop chaff to foil American radars. One P1Y hits USS RANDOLPH (CV-15) starboard side aft below the flight deck, killing 25 men and wounding 106.

I-58 receives the order to return to Kure.

16 March 1945:
Returns to Hikari, where two remaining kaiten are debarked.

17 March 1945:
Returns to Kure.

Late March 1945:
Battle training with kaiten in the Inland Sea.

31 March 1945: The Fifth Kaiten Mission:
I-58, I-44, I-47 and I-56 are in the "TATARA" group formed to attack American shipping anchored off Okinawa. I-58 arrives at Otsujima to embark kaiten, then departs for Hikari.

1 April 1945: American Operation "ICEBERG" - The Invasion of Okinawa:
Admiral Raymond A. Spruance's Fifth Fleet, including more than 40 aircraft carriers, 18 battleships, 200 destroyers and over 1,000 support ships surround Okinawa. LtGen Simon B. Buckner Jr's Tenth Army (7th, 77th, 96th Infantry and 1st, 6th Marine divisions) makes amphibious landings and begins the battle to take the island from LtGen Ushijima Mitsuru's 32nd Army defenders.

That same day, I-58 departs Hikari for Okinawa with the "TATARA" group.

4 April 1945:
At daybreak, I-58's Type 13 radar picks up an approaching aircraft. Hashimoto dives immediately.

5 April 1945:
I-58 is forced to dive by aircraft many times.

6 April 1945:
In addition to American aircraft, the weather is bad, the navigator has trouble getting a fix on I-58's exact position and her batteries are almost depleted. Hashimoto surfaces in daylight, but a flying boat appears almost immediately. I-58 is forced to dive and later many more times in the day, but she finally arrives off Amami-Oshima, albeit behind schedule.

7 April 1945: Operation "TEN-1-GO"- The Surface Special Attack Unit's Sortie to Okinawa:
I-58 is ordered to penetrate the invasion fleet anchorage on the west coast of Okinawa and to launch its kaitens there to support the attack by battleship YAMATO. Later that day, Hashimoto receives a signal about the sinking of YAMATO.

8 April 1945:
Early in the morning, when I-58 is proceeding to the Okinawa, area, her lookouts sight a Martin PBM-3 "Mariner" seaplane that had not been picked up by her radar. Hashimoto crash-dives.

10 April 1945:
Hashimoto reports that he is unable to break through the American ASW defenses from the western direction. He heads towards Kyushu to recharge the batteries.

11 April 1945:
After recharging her batteries, I-58 heads back to Okinawan waters. The submarine is spotted by aircraft repeatedly, but manages to escape each time.

14 April 1945:
At 2320, LtCdr Hashimoto again reports about the ASW defenses. Vice Admiral Miwa redirects I-58 to an area between Okinawa and Guam to attack enemy communications there.

17 April 1945:
At 2355 (JST), the Sixth Fleet HQ cancels all operations of the Tatara group.

21 April 1945:
I-58 is ordered to return to Kure.

25 April 1945:
At about 0100, while recharging her batteries on the surface, I-58 picks up an enemy ship on her radar. She dives and later identifies the well-lit enemy as a hospital ship. Hashimoto allows it to pass. Early in the morning, I-58 is detected by three American destroyers and depth-charged. LtCdr Hashimoto evades the chase, diving to 300-feet.

29 April 1945:
Arrives at Hikari. Kaitens and their pilots are debarked.

30 April 1945:
Arrives at Kure.

1 May 1945:
Vice Admiral, the Marquis, Daigo Tadashige (former CO of ASHIGARA) assumes command of the Sixth Fleet from Vice Admiral Miwa.

May 1945:
Refit at Kure Navy Yard. I-58's catapult and hangar are removed. This increases the number of kaiten she is able to carry to six. All torpedoes are fitted with underwater access tubes. I-58 is also fitted with a snorkel and Type 3 sonar. Her Type 22 radar is remounted on a pedestal in front of the conning tower.

22 June 1945: XXth Air Force Raid on Kure:
One hundred sixty-two USAAF B-29s bomb Kure. They destroy incomplete submarines I-204 and I-352 and damage RO-67. I-58 is not damaged although there are several near-misses.

16 July 1945: The Ninth Kaiten Mission:
I-58 is in the "TAMON" Group with I-47, I-53, I-363, I-366 and I-367. She departs Kure for the kaiten base at Hirao, flying the "Hi-Ri-Ho-Ken-Ten” and Usa-Hachiman shrine banners.

17 July 1945:
In the morning, I-58 departs Hirao for the Bungo Strait to carry out a deep-diving test. One of the kaiten periscopes is found to be defective. I-58 returns to Hirao to replace it.

18 July 1945:
In the evening, I-58 departs Hirao to attack shipping E of Philippines. LtCdr Hashimoto travels submerged in daytime and on the surface at night.

22 July 1945:
About this time Fleet Radio Unit, Pacific (FRUPAC) intercepts a Sixth Fleet radio transmission regarding the composition and patrol areas of the TAMON group. FRUPAC alerts CINCPAC of the positions of at least four kaiten-carrying submarines. This information, classified "ULTRA" top-secret, is not passed further.

26 July 1945:
Tinian, Marianas. Captain (later Rear Admiral-Ret) Charles B. McVay, III's USS INDIANAPOLIS (CA-35) arrives from San Francisco and delivers parts and nuclear material for the Hiroshima and Nagasaki atomic bombs.

Captain Charles B. McVay, III

27 July 1945:
LtCdr Hashimoto takes up position on the Guam-Leyte route and moves westward.

28 July 1945:
Philippine Sea, 300 miles N of Palau. At0530, I-58 is forced down by a radar-equipped airplane. After 1400 Hashimoto sights a large tanker, escorted by a single destroyer. At 1431, kaiten No. 2, piloted by FPO1C Komori Kazuyuki is launched against the tanker, followed Lt(jg) Ban Shuji's No. 1, targeting the destroyer, at 1443.

I-58's target is the 6,214-ton armed cargo ship WILD HUNTER (ex-EXPOUNDER), en route to Manila. At 1620 (local) WILD HUNTER's lookouts sight a periscope at 10-25N, 131-45E. Twenty-eight minutes later another periscope is spotted. The cargo ship engages the attacker with his 3-inch gun, maneuvering radically to present a smaller target. After several shots the periscope disappears.

Aboard I-58, two explosions are heard at 1520 and 1530, but a rain squall prevents Hashimoto to verify the results of his attack. After surfacing his radar detects no targets in the vicinity. He later reports both ships as sunk. I-58 heads SE, to the intersection of the Leyte-Guam and Palau-Okinawa routes.

That same day, INDIANAPOLIS arrives at nearby Guam. Since she is not equipped with sonar or hydrophones, McVay requests a destroyer escort. His request is denied. McVay's orders give him discretion as to whether or not to zigzag while under way. INDIANAPOLIS begins the trip from Guam to Leyte unescorted; the first major warship to do so during the war without equipment to detect enemy submarines.

USS INDIANAPOLIS (CA-35)

29 July 1945:
Philippine Sea, 250 miles N of Palau. At sunset, the INDIANAPOLIS is zigzagging at 17 knots in overcast weather. Captain McVay orders zigzagging ceased because of poor visibility. At 2305, following a radar check, I-58 surfaces. She is heading south when her navigation officer Lt Tanaka Hirokoto (72) spots a ship approaching from the east, 90-degrees off the port beam at 11,000 yards. LtCdr Hashimoto identifies the target as an IDAHO-class battleship. The target is making 12 knots and not zigzagging.

Hashimoto dives and prepares to attack with conventional torpedoes. He also alerts FPO1C Shiraki Ichiro to man No. 6 kaiten, with No. 5 (FPO1C Nakai Akira, both bow kaiten) as reserve, but he doubts the pilots can find the target in the dark with their short (2.9-m) Type 97 periscopes.

When the distance is down to 4,400 yards, Hashimoto realizes that INDIANAPOLIS will pass by so close that his torpedoes will not have time to arm. He orders right rudder and begins a long circle to increase the range.

At 2326 (JST), Hashimoto changes the torpedo data computer setup to a 60-degree port angle on the bow. At a range of 1,640 yards he fires a spread of six Type 95 Model 2 torpedoes with 2-second intervals, all set to the depth of 4 meters. He observes three equally spaced hits on the starboard side. The first is forward of the No. 1 turret, the second is abreast of the same turret, followed by an explosion and bright red flame. The third is near the bridge, abreast the No. 2 turret. Hashimoto sees that his target is stopped, is listing to starboard and down by the bow. He decides another attack is necessary and dives to 100 feet to open the range, reloading his two forward torpedo tubes. [3]

30 July 1945:
At 0027, INDIANAPOLIS capsizes and sinks by the bow at 12-02N, 134-48E. Thirty minutes after his last observation, Hashimoto raises his periscope, but his target is gone. After surfacing a new check reveals no further traces of his victim. I-58 departs the area at full speed, heading north while recharging its batteries. [4]

At 0300, Hashimoto reports to the Sixth Fleet HQ that he sank an "IDAHO-class battleship."

A failure of the USN's Movement Reporting System causes an 84-hour delay in search and rescue activities. Of her crew of 1,196, 883 are lost, more than half to the sea and sharks.

Captain McVay and 315 survivors are finally spotted by LtCdr George Atteberry's Lockheed PV-1 "Ventura" bomber that drops some supplies and radios for help. Atteberry is followed by Lt Adrian Marks' Consolidated PBY-5A "Catalina" floatplane that lands on the water. Marks and a few succeeding planes start picking up survivors while they wait for ships to reach the scene. Later, the survivors are rescued by the high-speed transports USS RINGNESS (APD-100) and USS REGISTER (APD-92).

1 August 1945:
FRUPAC intercepts I-58's radio transmission about the sinking and passes it to CINCPAC. Since there are no battleships in the area of the claimed sinking, the report is not investigated. This further contributes to the delay in the search for INDIANAPOLIS' survivors.

At 1500, I-58 surfaces and her lookouts sight an unescorted westbound merchant ship of about 9,000-tons at 20,000 yards. LtCdr Hashimoto gives chase at 15-knots, but is unable to close the target.

9 August 1945:
260 miles NE of Aparri. After 0800 Hashimoto sights a zigzagging convoy of ten transports escorted by three destroyers at 7,700 yards (in reality the hunter-killer team Task Group 75.19 led by USS SALAMAUA (CVE-96), carrying out ASW sweeps on the convoy route between Leyte and Okinawa).

Kaiten Nos. 3, 5 and 6 are readied for launch, but No. 3 and No. 6 suffer engine malfunctions. No. 5, piloted by FPO1C Nakai Akira, is launched first from 5,500 yards. After a destroyer from the "convoy" appears to be closing the range, Ens Mizui Yoshio's No. 4 kaiten is also launched.

At 1143, CortDiv 70's USS JOHNNIE HUTCHINS' (DE-360) lookouts report sighting a whale 2,000 yards ahead, but it is soon identified as a midget submarine. LtCdr Hugh M. Godsey orders battle stations and heads towards the submarine. At 1208, a surfaced object resembling a "floating iron boiler" about 45 ft long is sighted. JOHNNIE HUTCHINS engages the target with all guns. Nakai's torpedo passes down her port side at 2 knots, trying to point its bow at the DE.

JOHNNIE HUTCHINS' soundman then reports noises of another "submarine" at 700 yards. Next, a periscope is sighted on the port bow. LtCdr Godsey decides to attack the new target with depth charges while shelling the first one.

At 100 yards a direct hit from a 5-inch stern gun is scored on Nakai's kaiten. It is holed and sinks immediately at 20-20N, 126-57E. Meanwhile Mizui's No. 4 kaiten dives and its wake passes down the starboard side of HUTCHINS. A pattern of Mk. 8 magnetic depth charges is dropped and three explosions are heard, after which the contact is lost. ComCortDiv 70 in USS WILLIAM SEIVERLING (DE-441) orders a scouting line formed of four DEs to search for other submarines in the area.

At 1332, eight miles from the area of the first two contacts, JOHNNIE HUTCHINS' lookouts sight another periscope. A depth-charge attack results in a violent explosion, throwing a 30-feet geyser of water in the air. The concussion is felt on WILLIAM SEIVERLING over a mile away.

Four more DEs join the hunt until 1400 the next day, but no further contacts are made. USS JOHNNIE HUTCHINS is credited with probable destruction of two midget submarines and the possible destruction of a third. Her crew is awarded the Navy Unit Commendation.

I-58 comes to periscope depth after her soundman reports a distant explosion. In Hashimoto's opinion, the previously sighted destroyer has disappeared. He heads northwards to evade the hunt, making radical maneuvers to confuse enemy sonars. After sundown I-58 surfaces to recharge her batteries, but is forced under by an approaching airplane.

12 August 1945:
360 miles SE of Okinawa. Around 1700, when the surfaced I-58 is running northwards at 12 knots, her Type 3 detector detects multiple radar impulses. Soon thereafter masts are sighted on the horizon. LtCdr Hashimoto orders to dive.

At 1716, a 15,000-ton seaplane carrier escorted by one destroyer is sighted. Kaiten No. 3 piloted by FPO1C Hayashi Yoshiaki is launched at 1758 from an estimated distance of 8,800 yards. In reality, the "seaplane carrier" is Landing Ship Dock USS OAK HILL (LSD-7), escorted by THOMAS F. NICKEL (DE-587) enroute from Okinawa to Leyte.

At 1826, the lookouts on OAK HILL report a periscope 1000 yards away on the port quarter. LtCdr Claude S. Farmer's THOMAS F. NICKEL turns toward the attacker, making flank speed. At 1830 the lookouts on NICKEL sight a wake of an apparently broaching torpedo. The DE heads towards the direction opposite to that of the torpedo and fires a shallow pattern of depth charges from her K-guns, mistakenly indetifying the attacker as a conventional submarine. NICKEL's sonar fails to make a contact.

At 1837, OAK HILL reports an incoming torpedo wake directly astern. The lookouts on the DE observe a "submarine" breaking the surface in the wake of OAK HILL. When THOMAS F. NICKEL attempts to ram it, a scraping noise is heard in her forward and after fire rooms and the after engine room along the port side of the bilge. At 1842, OAK HILL reports that the "object" is still chasing her about 2,000 yards astern, although now moving somewhat slower. Suddenly, the kaiten stops, breaks surface and self-detonates, sending smoke and water about 200 ft into the air at 21-15N, 131-02E.

At 1905, lookouts on THOMAS F. NICKEL sight another periscope dead astern of OAK HILL. The DE charges, firing a shallow depth charge pattern. A secondary explosion follows 50 ft outside of the pattern, throwing a black 50-feet geyser of oil and water in the air. A long oil slick is also sighted.

17 August 1945.
Arrives at Hirao.

18 August 1945:
Proceeds to Kure.

September 1945:
Kure. I-58 is surrendered to the Allied Powers.

5 October 1945:
I-58 is inspected at Kure. She has over 30 tons of fuel aboard, while all ammunition and usable equipment have been removed.

November 1945:
Transferred from Kure to Sasebo.

20 November 1945:
Cdr Hashimoto is appointed the CO of YUKIKAZE, but does not assume that command.

27 November 1945:
Cdr Hashimoto leaves the boat. A skeleton crew led by the torpedo officer Lt Tanaka Toshio (68) remains aboard.

30 November 1945:
Removed from the Navy List.

3 December 1945:
As details of the INDIANAPOLIS disaster begin to become public - arguably the worst in American naval history - Fleet Admiral Ernest King, Chief of Naval Operations convinces SecNav James Forrestal that they need a scapegoat. King brushes aside Fleet Admiral Chester Nimitz's recommendation that Captain McVay be given only a letter of reprimand. Instead, he ensures that formal charges are brought against McVay.

Although 700 navy ships are lost in combat in WWII, McVay is the only captain that is court-martialed. He is tried for "hazarding his ship by failing to zigzag during conditions of good visibility" and "culpable insufficiency in the performance of duty" for failure to order Abandon Ship in a timely manner.

Cdr Hashimoto testifies at McVay's trail. He states that zigzagging would have made no difference. Four-time Navy Cross winner Cdr (later Vice Admiral) Glynn R. Donaho (former CO of FLYING FISH and PICUDA) also testifies that zigzagging would have been ineffective. King's court ignores both Hashimoto's and Donaho's testimonies and finds McVay guilty.

After Nimitz succeeds King as Chief of Naval Operations, he presses Secretary Forrestal to remit McVay's sentence in its entirety. Forrestal agrees. This releases McVay from arrest and restores him to duty, but he is never given another command at sea.

1 April 1946: Operation "ROAD'S END:"
I-58 is stripped of all usable equipment and material and towed from Sasebo to an area off Goto Retto by the submarine tender USS NEREUS (AS-17). She is blown up with C-2 demolition charges at 32-37N, 129-17E. The first I-58 (now designated I-158) is scuttled during the same operation.

1949:
Captain McVay retires from the Navy with a "tombstone" promotion to Rear Admiral. He broods over the loss of INDIANAPOLIS and her crew for the rest of his life.

July 1959:
Hirao Town, Yamaguchi Prefecture. A monument is erected to honor Special Attack Corps Kaiten (human torpedo) pilots who trained at Hirao (the IJN's third kaiten training base after Otsushima and Hikari) and died during WWII including five pilots from I-58, who died in kaiten attacks in Okinawan waters in 1945.

Painted hull number "35" on port side of ship.		Spare parts box from USS INDIANAPOLIS in over 16,000 feet of water.
One of INDIANAPOLIS' main gun turrets.		Torpedo damage to forward starboard section.
Secondary gun mount.		Bofors 40-mm AAA gun.
INDIANAPOLIS' bell.		R/V PETREL lowers autonomous underwater vehicle (AUV) that can make a submerged run for up to 20 hours.