(Type D1 submarine by Takeshi Yuki)
IJN Submarine I-373: Tabular Record of
© 2001-2017 Bob Hackett & Sander Kingsepp
15 August 1944:
Laid down at Yokosuka Navy Yard as a Type
D-2 Modified "Tei-gata Kai" transport submarine No. 2962.
5 October 1944:
Numbered I-373 and provisionally attached to Yokosuka
30 November 1944:
25 March 1945:
Captain Hori Takeo (50)(former CEO of I-369) is appointed
the Chief Equipping Officer (CEO).
5 April 1945:
Lt (Cdr, posthumously) Inobe Yukio (66)(former torpedo
officer of RO-115) is appointed the CEO.
14 April 1945:
I-373 is completed, commissioned in the IJN and
attached to Yokosuka Naval District. Assigned to SubRon 11 for working-up. Lt
(promoted LtCdr 1 May) Inobe Yukio is the CO.
16 June 1945:
Departs Yokosuka for Sasebo. 
17 June 1945:
Arrives at Sasebo to undergo conversion to transport
150 tons of aviation fuel and additional cargo.
20 June 1945:
Reassigned to SubDiv 15, Sixth Fleet.
5 August 1945:
On that day, codebreakers at the USN Fleet Radio Unit,
Melbourne (FRUMEL), Australia, provide the following information:
"Submarine I-373 leaves Sasebo on 5th August on a transport run to Takao,
returning with a cargo of aviation petrol, rice, and sugar."
9 August 1945:
I-373 departs Sasebo on her first tanker run to
13 August 1945:
East China Sea, 200 miles SE of Shanghai. At 2010 (H),
I-373 is picked up by Cdr Robert R. Managhan's USS SPIKEFISH (SS-404) SJ radar.
The IJN submarine is zigzagging around a base course of 230 (T) at 10 kts; its
Type 13 air-search radar impulses are registered by SPIKEFISH's APR gear. At
2018, SPIKEFISH makes visual contact at 3,500 yds. Managhan begins tracking,
only to lose contact at 2118, when Inobe executes a feint in the southeastern
direction and then submerges.
14 August 1945:
At 0007, SPIKEFISH regains radar contact at 8,600 yds
and tracks the target until 0419 when the target is positively identified as an
enemy submarine. At 0424, Cdr Managhan fires a full salvo of six Mk. 14-3A
torpedoes at 1,300 yds. After receiving two hits, I-373 sinks by the stern at
29-02N, 123-53E. SPIKESFISH's soundman reports hearing loud sounds of escaping
At 0540 the surfaced SPIKEFISH passes through a heavy accumulation of
diesel oil and large quantity of debris. Five survivors are sighted, one of
which is forcibly taken aboard. The survivor identifies his submarine as the
(nonexisting) I-382. The remaining 84 sailors are lost.
I-373 is the last Japanese submarine sunk in World War II.
15 September 1945:
Removed from the Navy List.
 Several FRUMEL intercepts suggest that I-373 might have
made a supply run from Sasebo to Takao and back between the 3rd and the 26th
July. This is not confirmed by Japanese sources.
Special thanks go to Dr. Higuchi Tatsuhiro of Japan and Hans Mcilveen
of the Netherlands for info on FRUMEL intercepts.
– Bob Hackett and Sander Kingsepp.
Back to Submarine