Upon commissioning,
I-36 was attached to the
Kure Naval District — in the
Seto Inland Sea on and again from 3 to 5 June 1943.
Second kaiten mission At Kure,
I-36 began preparations on 22 December 1944 for her second
kaiten mission and visited Otsujima to pick up four
kaitens and their pilots on 27 December. On 29 December 1944,
I-36 was assigned to the
Kongo ("Steel") Kaiten Group along with the submarines
I-47, , , , and for an attack scheduled for dawn on 11 January 1945 on five different U.S. anchorages in widely separated locations; the date of the attack later was postponed to 12 January 1945.
I-36 departed Kure on 30 December 1944 in company with
I-53 and
I-58, bound for her target, Ulithi Atoll. While approaching Ulithi she ran aground on a
reef on 11 January 1945, but managed to free herself by blowing her main
ballast tanks. On 12 January 1945, she launched her four
kaitens between 03:42 and 03:57. A U.S. Navy
PBM Mariner flying boat of
Patrol Bombing Squadron 21 (VPB-21) dropped four depth charges on one of
I-36′s
kaitens in the lagoon and sank it.
I-36 returned to Kure on 21 January 1945, and the Japanese credited her
kaitens with sinking four ships, but post-World War II analysis concluded that they damaged the
ammunition ship and sank the
landing craft infantry .
Third kaiten mission On 28 February 1945:
I-36 and
I-58 formed the
Shimbu ("Divine Warriors") Group to attack American shipping off
Iwo Jima, where the
Battle of Iwo Jima had begun on 19 February 1945.
I-36 departed the
kaiten base at
Hikari carrying four
kaitens. On 6 March 1945, however, the Combined Fleet ordered the 6th Fleet to cease operations off Iwo Jima, and
I-36 returned to Kure on 10 March 1945. In mid-March 1945,
I-36 underwent a conversion in which her aircraft
hangar and
catapult were removed from her foredeck and replaced by fittings to carry two more
kaitens, bringing her
kaiten capacity to six. All of her
kaiten racks were fitted with access tubes to allow their pilots to man them while
I-36 was submerged, and a new air-search radar was installed.
Fourth kaiten mission The
Battle of Okinawa began on 1 April 1945 with the U.S. landings on
Okinawa. On 22 April 1945,
I-36 departed Hikari carrying six
kaitens to patrol in the Philippine Sea between the
Mariana Islands and Okinawa as part of the
Tembu ("Heavenly Warriors") Group. She sighted a U.S. Navy PBM Mariner on an
antisubmarine patrol off
Iheya Island in darkness on 25 April 1945. Early on the morning of 27 April 1945, she sighted a 28-ship U.S. convoy of
tank landing ships and
medium landing ships bound from
Saipan to Okinawa, at least some of which she misidentified as transports. Two of her
kaitens malfunctioned, but she launched the other four. At 08:23, the
high-speed transport sighted a passing torpedo wake, and at 08:25 her lookouts spotted a
periscope astern of her. She dropped four depth charges at the location she had sighted the periscope, and at 08:45 witnessed a huge explosion at , followed by debris rising to the surface. The destroyer escort , escorting the same convoy, also sighted a torpedo.
I-36 claimed her
kaitens sank four transports, but in fact they had no success against the convoy. She returned to Hikari on 30 April 1945 and disembarked her two remaining
kaitens and their pilots.
I-36 was engaged in
kaiten training off Otsujima on 17 May 1945 when one of her
kaitens, carrying a dummy warhead, collided with a target and sank, killing its pilot.
Fifth kaiten mission On 4 June 1945,
I-36 put to sea to patrol in the Philippine Sea as part of the
Todoroki ("Sound of Great Cannon") Group. She was on the surface in the
East China Sea west of
Osumi Kaikyo at on 10 June 1945 when the submarine — which misidentified her as a "RO-type submarine" — attacked her, firing two
Mark 18 torpedoes, which both missed. On 22 June 1945,
I-36 sighted the unaccompanied landing craft
repair ship , which she mistook for an oiler.
I-36 tried to launch two
kaitens, but they both malfunctioned, so she fired four conventional torpedoes, all of which exploded prematurely. The explosions slightly damaged
Endymion and
I-36′s commanding officer thought she took on a list, but
Endymion put on speed and escaped. On 28 June 1945,
I-36 was north-northeast of Truk when she sighted the
stores ship steaming alone from Saipan to Pearl Harbor at and launched a
kaiten.
Antares sighted the
kaiten′s periscope and wake off her starboard quarter at 13:29 and turned hard to starboard, causing the
kaiten to miss her astern. Her lookouts then spotted the
kaiten in her wake to port, turning to the right. At 13:31,
Antares opened fire on
kaiten′s periscope and began to
zigzag, and as her stern swung to starboard one of her guns hit the
kaiten, which disappeared. At 13:44,
Antares sighted
I-36′s periscope, and
I-36 broached.
Antares opened fire on
I-36 with her aft gun.
Antares signaled the destroyer , which was steaming independently to the
United States for overhaul, that she was under attack, and when
Sproston arrived on the scene she made sonar contact with
I-36 at a range of . At a range of she sighted a periscope passing from starboard to port and tried to ram the submarine without success, then dropped a full pattern of depth charges, later seeing an oil slick on the surface. She made six more depth-charge attacks without success. Meanwhile, aboard
I-36, a leak began in the forward torpedo room after more than 10 depth-charge explosions, and she launched two more
kaitens from a depth of . After
Sproston sighted the wake of an approaching
kaiten 60 degrees off her port
bow, she turned hard to port, causing the
kaiten to pass down her port side.
Sproston then sighted a
kaiten′s periscope off her port quarter and opened fire on it with her main battery, hitting the
kaiten and triggering a large secondary explosion. Other ships then arrived to increase the overnight radar coverage of the area, and on the morning of 29 June 1945 three destroyer escorts arrived to assist in the hunt for
I-36. After a thorough search of the area, all the ships departed.
I-36 escaped with a damaged
rudder. She was east of
Guam on 29 June when her sound operator heard a distant explosion at around 10:00 and later several more explosions identified as those of depth charges.
I-36 made for Japan. She was in the
Bungo Strait south of on 9 July 1945 when the submarine attacked her, mistaking her for a
Ro-60-class submarine, at . All four of
Gunnel′s torpedoes missed astern, and
I-36 arrived at Hikari later that day to disembark her remaining
kaitens and their pilots, and during the afternoon continued on to Kure, where she entered drydock for repairs.
End of war Undocked early on the morning of 6 August 1945,
I-36 moved into the harbor at Kure and moored to a
buoy. Later that morning, her crew witnessed the
atomic bombing of
Hiroshima. She was in the
Hayase Seto Channel in
Hiroshima Bay on 11 August 1945, preparing to get underway for the submarine base at
Hirao to participate in the
Shinshu-tai ("Divine Country Unit") kaiten mission when two Iwo Jima-based U.S. Army Air Forces
P-51 Mustang fighters subjected her to a
strafing attack at 10:40. The attack wounded her commanding officer and
navigation officer and damaged a diesel fuel tank and a radar. Repairs were estimated to take eight days. On 15 August 1945,
I-36 and
I-47 were at Kure when
Emperor Hirohito made his
surrender broadcast announcing the cessation of hostilities between Japan and the Allies.
I-36 was the only Type B1 submarine to survive World War II. ==Final disposition==