© 2001-2008 Bob Hackett & Sander Kingsepp
Revision 2
5 September 1944:
Completed at the Sasebo Navy Yard and registered in the Yokosuka Naval District. LtCdr Toyama Zenshin (former CO of I-38) is the Commanding Officer. Assigned to Rear Admiral Ishizaki Noboru's (former CO of HYUGA) SubRon 11, Sixth Fleet. I-48 is configured to carry four "kaiten" human torpedoes on her afterdeck (only two are fitted with access tubes). I-48 is also fitted with an air-search radar and an E27 radar detector.
13 October 1944: Operation "SHO-I-GO" - The Defense of the Philippines:
Admiral Toyoda Soemu (former CO of HYUGA), CINC, Combined Fleet, orders the SHO-I-GO plan activated.
7 December 1944:
I-48 is reassigned to SubDiv 15 in Vice Admiral Miwa Shigeyoshi's (former CO of KINU) Sixth Fleet.
8 December 1944:
I-48 is assigned to the "Kongo” (Steel) kaiten unit.
26 December 1944:
Inland Sea. I-48 finishes working-up and heads for the Otsujima base to embark her human torpedoes.
9 January 1945: The Second Kaiten Mission:
I-48 departs Otsujima with four kaitens as part of the Kongo group with I-36, I-47, I-53, I-56 and I-58 for a planned 21 January attack on the USN's Third Fleet anchorage at Ulithi.
21 January 1945:
15 nm NE of Yap island. At 1930, Lt Frank A. Yourek piloting a Martin PBM-3D Mariner of VPB-20 based at Tinian makes a radar contact with a surfaced submarine heading for Ulithi at 18 knots. He attempts to establish the nationality of the sub, which immediately crash-dives. Lt Yourek attacks the sub with two depth charges and then releases a Mark 24 "Fido" acoustic torpedo. I-48 (evidently with some kaitens already manned) receives serious damage and is forced to abort the mission.
Lt Yourek reports his sighting to Ulithi. A three-strong hunter-killer group is formed of CortDiv 65 destroyer escorts with LtCdr Edmund L. McGibbon, CO of USS CONKLIN (DE-439), in tactical command. McGibbon assumes the damaged submarine would head directly for Japanese-held Yap Island at an estimated submerged speed of 3 knots during the first night and day.
22 January 1945:
After no contacts are made, McGibbon decides to expand the search all the way to Yap.
23 January 1945:
15 nm NE of Yap Island. At 0310, USS CORBESIER (DE-438) makes a radar contact at about 9,800 yards. The target is heading 210 degrees making 18 knots. After CORBESIER closes to investigate, I-48 crash-dives. At 0336, CORBESIER obtains a sound contact and fires a salvo of Mark 10 "Hedgehog" projector charges but misses.
CONKLIN and RABY (DE-698) join the chase. CORBESIER makes five more Hedgehog attacks, all with negative results. Finally, contact is lost.
At 0902, CORBESIER regains contact and executes another Hedgehog attack, again with negative results. At 0912, CORBESIER reestablishes sound contact with the sub, but loses it before an attack can be made.
CONKLIN makes a new Hedgehog attack at 0934, from a distance of 550 yards. Seventeen seconds later, four or five explosions are heard from an estimated depth of 175 feet. At 0936, a violent explosion occurs, temporarily disabling CONKLIN's engines and steering gear. Huge air bubbles come up alongside; soon thereafter oil and debris surface. Large quantities of human remains are likewise sighted.
17 nm N of Yap. A motor whaleboat from CONKLIN picks up pieces of planking, splintered wood, cork, interior woodwork with varnished surfaces, a sleeve of a knitted blue sweater containing flesh, chopsticks and a seaman’s manual. I-48 is sunk with her 122-strong crew and four kaiten pilots at 09-55N, 138-17.30E. [1][2]
31 January 1945:
HQ, Sixth Fleet attempts to contact I-48 and orders her to return to Kure.
10 May 1945:
Removed from the Navy List.
Authors' Notes:
[1] This was CONKLIN’s second submarine kill. The first (I-37, another kaiten carrier) was shared with USS MCCOY REYNOLDS (DE-440).
[2] Sources disagree on the exact location of I-48’s loss. The alternative location is 09-45N, 138-20E.
[3] The Kongo group's Action Report credits I-48's kaiten with four ships, including a cruiser and an oiler. None of the claims is substantiated, since no launches were made.
Special thanks for help in preparing this TROM go to Dr. Higuchi Tatsuhiro of Japan.
– Bob Hackett and Sander Kingsepp.
