IJN I-58

History

The last Japanese submarine built in the B-3 family became the I-58. She was launched on December 26, 1942, on June 30, 1943, and completed on September 7, 1944 at the naval shipyard in Yokosuka, Japan, home port of the mighty battleship Yamato. She was launched in early December 1944 and assigned to the 15th Submarine Detachment of the Japanese Navy under the command of a lieutenant. Assigned to Commander Mochitsura Hashimoto. I-58 is best known for sinking the USS Indianapolis and serving as the mothership for several manned Kayten suicide torpedoes.

She lived until the end of World War II, then was deliberately sunk in 1946.

Type B Series

Previous B-1 and B-2 series ships had a range of 14,000 nautical miles. As such, the B-3 line is designed as a long-range patrol craft capable of operating in the depths of the vast Pacific Ocean, the largest sea body on Earth.

She carried 842.8 tons of fuel, which allowed her to reach 21,000 nautical miles at 16 knots. The maximum diving depth of 100 m (330 ft) remains the same for all B-Series vessels, including the B-3. However, the increased range was a remarkable feat for WWII submarines.

This allowed the B-3 to patrol, target and sink all Allied ships within its extended range. The Imperial Japanese Navy (IJN) wanted more of these submarines, but with all the services competing for Japan's limited available war resources, the IJN decided to build fewer but larger submarines with longer range.

Between September and December 1944, the I-58 had its 140mm deck guns removed to make room for the Kaiten suicide torpedo bay. Initially, two compartments were installed and linked by a Type 22 ground/air search radar system mounted on top of the aircraft hangar (I-58 was fitted with a Yokosuka seaplane). The bridge is fitted with an E27/Type 3 radar system.

I-58 reports to SubRon 11 Group of IJN Sixth Fleet for inland training.

Suicide torpedo

On December 2, 1944, a special meeting was held at IJN's Sixth Fleet to assess the combat results of Kaiten's first "Manned Torpedo" mission at Ulithi. Attended by 200 staff officers and various other personnel, the meeting was held on board the 6th Fleet flagship IJN Tsukushi Maru. After reviewing available reconnaissance photos and obtaining after-action reports from participating Japanese commanders, the U.S. Navy decided to lose three aircraft carriers and two battleships early.

In reality, however, no American aircraft carrier or battleship was sunk. Such inaccurate or exaggerated claims about enemy casualties, which are common on both sides during wartime, have proven to be good for morale but very bad for war planning decisions.

Based on these reported successes, the Kaiten is considered a viable offensive weapon. These Kamikaze torpedoes required a crew of two, were 45 feet long, and were armed with 3,000-pound warheads.

On December 4, 1944, I-58 was assigned to SubDiv 15 as part of Vice Admiral Miwa Shigeyoshi's Sixth Fleet. Four days later, the ship was assigned to the Congo (Diamond) group along with submarines I-36, I-47, I-48, I-53 and I-56.

The group is accused of attacking the U.S. fleet at five anchorages with their Kaiten torpedoes. In particular, I-58 received target assignments at Apra Harbor, Guam, and the attack was planned to begin on January 11, 1945.

I-58 was transferred to Ohtsuji Island for kaiten launch training from December 19, 1944 to December 24, 1944. She then leaves Sasebo for Wu to get supplies and rearm. On December 29, she left Wu for Ohtsuji Island. Two days later, I-58 received four Kaiten torpedoes and the corresponding crew, and took the I-36 submarine to Wu.

The group arrived near Guam on January 6, 1945. Soon, I-58 was informed by a reconnaissance plane (Nakajima JC6N2 Saiun-Kai "Myrt") that several enemy ships were in Apra Harbor - an escort carrier, two destroyers, a submarine , 20 transport ships and four floating docks.

The decision was to enter port and launch Kaiten torpedoes on January 11, 1945.

Incorrect reporting can lead to bad decisions

I-58 fired all four Kaitens, and as Lt. Commander Hashimoto Motsu left the area, he noticed two plumes of smoke rising. When Kaiten No. 4 blew up immediately after takeoff, he was forced to retreat quickly.

On January 22, 1945, I-58 arrived at the Japanese base at Wu, and Hashimoto learned that he was credited for sinking an American aircraft carrier and a large merchant ship (a tanker). Unbeknownst to Hashimoto, the well-publicized sinking of two ships also proved to be a miscalculation of operations, but it helped strengthen the use of Kaitens in future raids.

Process TAN 2

The I-58 returned to Japan for an upgrade with four new Kaiten suicide torpedoes and their respective crews. As part of detachment operations, I-58 was then ordered to attack the 450-ship U.S. Fifth Fleet stationed near Iwo Jima. The Americans occupied the island and its most important airport, Motoyama. I-58 and I-36 regrouped as part of the Shimbu attack group, responsible for island communications attacking Iwo Jima.

The I-58 left the light on February 28, 1945, and is now equipped with a Type 13 air search radar system.

On March 1, 1945, I-58 left Kure Port, fully armed, and returned with a reward, crossing the Bungo Strait. Several close calls with the U.S.-spotting plane subdued the submarine but limited her discovery.

On March 7, I-58 surfaced as usual to recharge its depleted battery (needed for underwater operations). Their initial mission was to attack ships moored near Iwo Jima, but then the combined Japanese naval fleet was ordered to stop operations near Iwo Jima and proceed to Okinotori Island (Douglas Reef) to carry out a project called "TAN # 2".

Hashimoto decided to drop two of the four Kaitens and head to Okinotori Island at flanking speed.

TAN 2 was a joint Japanese Army-Navy attack program involving 24 twin-engine Yokosuka bombers, each carrying a 1,763-pound bomb, on kamikaze missions from Kanoya airfield to U.S. Navy ships. Attack at Ulithi's port. Station I-58 was intended to be a radio beacon for bombers heading to Ulithi. Six bombers successfully hit the carrier USS Randolph CV-15, causing moderate damage to its structure.

Finding no viable targets to fire on itself, I-58 returned to the light to disembark the two remaining Kaiten and their crew. Sometime in late March 1945, I-58 was transferred to Kure and received further Uchikai kaiten training.

Backdoor battle

The Tatara Group with I-58 was formed to attack the U.S. Fifth Fleet anchored near Okinawa. The fleet consists of 40 aircraft carriers, 18 battleships, 20 Verniers, 200 destroyers, and more than 1,000 support ships of various types to participate in Operation Iceberg, the invasion of Okinawa. On April 4, 1945, I-58 arrived at her station with Kaitens in the Hikari cargo hold and found the air filled with American aircraft, forcing her to remain submerged during the day and forced to use her snorkel to replace the stagnant interior air.

Bad weather quickly affected future I-58 operations in the area, and the constant diving drained their batteries.

Go to Okinawa

A special surface attack force - including the battleship Yamato, which appears to be on its own suicide mission - sailed to Okinawa to attack alongside waiting Japanese Navy submarines. The I-58 was designed to penetrate the U.S. invasion fleet off the west coast of Okinawa and deliver a powerful Kaiten payload. This would help support the Yamato's subsequent offensive and rescue the besieged Japanese on the island. However, on April 7, Hashimoto received news that the Yamato had been sunk by the Allies.

Over the next eight days, I-58 made numerous attempts to breach Fifth Fleet's anti-submarine defenses (ASW), but failed, and was eventually ordered back to Guam.

On April 25, 1945, she surfaced to recharge and spotted an Allied hospital ship on radar. Hashimoto let the surface ships pass undisturbed, but was spotted by no fewer than three American destroyers, who immediately pursued. While loaded with depth charges, the I-58 dived to depths of up to 300 feet and eventually avoided damage.

She arrives at Light and unloads her Kaitens and her crew.

I-58 arrived in Kure in May 1945. Some modifications were made to its structure to allow for the installation of an additional pair of manned Kaiten torpedoes. As a result, the hangars and catapults used to manage the internally installed Scout seaplanes were removed. The I-58 now carries six Kaiten suicide torpedoes, each with its own access tube. In addition to her new Type 3 sonar, patrol aircraft are no longer required for aerial reconnaissance on the horizon due to her extended range and Type 22 ground/air radar (moved to the conning tower).

Wu was then attacked by American bombers, but I-58 escaped unscathedother submarines were not so lucky. Major Hashimoto continued to train his crew and conduct patrols of Allied ships in the area.

USS Indianapolis

On July 26, 1945, the heavy cruiser USS Indianapolis (CA-35) arrived at Tinian in the Mariana Islands at high speed to covertly transport part of the "Little Boy" atomic bomb unescorted Nuclear material (uranium)" will (sometimes) be dropped on the Japanese city of Hiroshima. I-58 happened to be patrolling the area between the Mariana Islands and the Philippines, at the time in the Philippine Sea near Leyte. The aircraft carrier USS Indianapolis left Hiroshima Headed to Wright (unescorted as its mission was classified as top secret) and without any anti-submarine weaponry.

To encourage some self-defense against enemy submarines, surface crews took a "zigzag" route at sea. Indianapo The USS Leith followed their training, but poor visibility quickly hindered their navigation.

At 11:05 p.m., as IJN I-58 surfaced and moved south, Lieutenant Colonel Hashimoto spotted a surface ship approaching from the east, approximately 11,000 yards away. The ship was further identified as a U.S. Navy Idaho-class battleship, outlined by the rising moon, with a straight-line speed of 12 knots. It was decided to attack enemy ships with conventional torpedoes at 1,650 yards. Although he still had the advantage, Hashimoto ordered six Type 95 torpedoes to be fired at the American ships.

He observed three torpedo hits from time to time on the starboard side of the battleship. The first occurred near the bow and the second was recorded at the first tower. A third torpedo hit the ship, just below the bridge near Tower 2. Hashimoto decided to attack again to shoot down the American ships and ordered I-58 to dive.

This helped keep his submarine from being discovered. Her two forward torpedo tubes were reloaded. By the time I-58 reached periscope depth, the Indianapolis had sunk -- in just 12 minutes. Hashimoto took his ship and crew full speed north out of danger.

He signaled to the IJN Sixth Fleet that I-58 had confirmed the sinking of an American warship.

The crew of the USS Indianapolis spent a terrifying five days in the water, at risk of dehydration, exposure to Pacific sun and salt water and the threat of shark attack. Many have died due to the U.S. Navy's unresponsiveness and trips - the USS Indianapolis has sent a distress signal, but three of the party's recipients have not responded.

Even the intercepted I-58's claim that they sank a battleship has not been investigated. USS Indianapolis' lack of support ships also left much of her crew in limbo. During normal U.S. Navy operations, a destroyer (equipped with anti-submarine warfare) would be assigned to a capital ship such as the USS Indianapolis. Had Indianapolis received such an order, the destroyer could have thwarted the I-58 attack.

The decision proved to be extremely fatal in many ways. From a wreck perspective, USS Indianapolis CA-35 had a crew of 1,196. 300 people were killed in the sinking, 883 people were killed in the incident. Half died from drowning, the others from shark attacks. In the end, only 316 sailors survived, all of which were stumbled upon by PV-1 Ventura during routine patrols.

A full rescue operation was soon carried out. Despite all the suffering, the crew of the USS Indianapolis went through hell a month before the end of the war, making her the last U.S. Navy ship to be killed in enemy action. In her name, she went to World War II with 10 battle stars.