(Type B2 submarine)

IJN Submarine I-40: Tabular Record of Movement

2001-2017 Bob Hackett & Sander Kingsepp
Revision 1

18 March 1942:
Laid down at Kure Navy Yard as Type B2 Submarine No. 370.

20 August 1942:
Renumbered I-40 and provisionally attached to Yokosuka Naval District.

10 November 1942:

10 May 1943:
LtCdr (Captain, posthumously) Watanabe Katsuji (55)(former CO of I-169) is appointed the Chief Equipping Officer (CEO).

31 July 1943:
I-40 is completed, commissioned in the IJN and attached to Yokosuka Naval District. Assigned to SubRon 11, First Fleet, for working-up. LtCdr (promoted Cdr 1 November) Watanabe Katsuji is the Commanding Officer.

August 1943:
Inland Sea, off Kure. I-40 participates in Type 3 sonar and Type 1 Model 3 magnetic anomaly detector (aka the "Y-device") tests, carried out by the minelayer NUWAJIMA. I-40 plays the role of the ASW target.

31 Oct 1943:
Reassigned to SubRon 1's SubDiv 2, Sixth Fleet.

13 November 1943:
Departs Yokosuka for Truk.

19 November 1943:
Arrives at Truk.

20 November 1943: American Operation "Galvanic" - The Invasion of the Gilberts:
The Americans invade Tarawa and Makin Islands. The invasion fleet of 200 ships includes 13 battleships and 11 carriers.

Vice Admiral (Admiral, posthumously) Takagi Takeo (former CO of MUTSU), CinC, Sixth Fleet (Submarines) orders I-40, -19, -21, -35, -39, -169, -174, I-175 and RO-38 to proceed to Tarawa to attack the invasion ships.

22 November 1943:
Departs Truk for the Makin area on her first war patrol, but is MIA thereafter. [1]

26 November 1943:
Takagi orders I-19, I-40, I-169 and RO-38 to form a picket line N of Makin.

2 December 1943:
Headquarters, Sixth Fleet sends a signal to I-40, I-19 and I-20 inquiring as to their respective locations.

21 February 1944:
Presumed lost in the Gilberts with all 97 hands.

30 April 1944:
Removed from the Navy List.

Authors' Notes:
[1] There are several theories regarding the loss of I-40. Carpenter and Polmar (1986) credit land-based naval aircraft (p. 36) and USS RADFORD (DD-446)(p. 106); Boyd and Yoshida (1995) credit USS RADFORD with her destruction. Alternatively I-40 could have been the victim of USS BOYD (DD-544) on 26 November (also identified as I-39).

Special thanks for help in preparing this TROM go to Dr. Higuchi Tatsuhiro of Japan.

Bob Hackett and Sander Kingsepp.

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