IJN Submarine I-48: Tabular Record of
© 2001-2016 Bob Hackett & Sander Kingsepp
19 June 1943:
Laid down at Sasebo Navy Yard as Submarine No.
10 June 1944:
LtCdr (Cdr, posthumously) Toyama Zenshin (59)(former CO
of I-38) is appointed Chief Equipping Officer.
12 December 1944:
Launched and renumbered I-48.
5 September 1944:
Sasebo. Completed and attached to Yokosuka Naval
District. LtCdr Toyama Zenshin 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). She carries a Type 13 air-search radar and an E27
Type 3 radar detector.
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 "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 the last unit of the "Kongo" group for a planned 21 January
attack on the USN Third Fleet anchorage at Ulithi, Carolines. No messages are
received from I-48 after her departure.
21 January 1945:
18 miles W of Ulithi. 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 submarine with two depth charges and then releases a Mk.24 "Fido"
acoustic torpedo. I-48 (evidently with some kaitens already manned) is forced to
postpone the attack.
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 the 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 miles NE of Yap Island. At 0310, USS CORBESIER
(DE-438) makes a radar contact at about 9,800 yds. The target is heading 210
degrees at 18 kts. After CORBESIER closes to investigate, I-48 dives. At 0336,
CORBESIER obtains a sound contact and fires a salvo of Mk.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, losing the
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 yds. Seventeen seconds later,
four or five explosions are heard from an estimated depth of 175 ft. 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 miles 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 118-strong crew and four kaiten pilots at 09-55N,
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.
 This was CONKLIN's second submarine kill. The first
(I-37, another kaiten carrier) was shared with USS MCCOY REYNOLDS (DE-440).
 Sources disagree on the exact location of I-48's loss. An
alternative location is 09-45N, 138-20E.
 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 go to Dr. Higuchi Tatsuhiro of Japan.
– Bob Hackett and Sander Kingsepp.
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