(KS type RO-109 scanned from "Submarines of the Imperial Japanese Navy" by Polmar and Carpenter)

IJN Submarine RO-117:
Tabular Record of Movement

© 2001-2016 Bob Hackett & Sander Kingsepp
Revision 3

16 January 1943:
Kobe. Laid down at Kawasaki Jukogyo (Heavy Industries) K.K. as the 525-ton Kaisho (KS) Type submarine No. 408.

5 July 1943:
Redesignated RO-117 and provisionally attached to Yokosuka Naval District.

13 September 1943:

20 December 1943:
Lt (promoted LtCdr 1 May 1944; Cdr, posthumously) Enomoto Yasuo (63)(former CO of RO-62) is appointed Chief Equipping Officer.

31 January 1944:
Completed and attached to Yokosuka Naval District. Assigned to SubRon 11. Lt Enomoto Yasuo is the CO.

31 March 1944:
Departs Japan on her first war patrol in company of RO-116 to intercept an enemy task force reported in the Palau area.

13 April 1944:
Returns to Kure.

4 May 1944:
Reassigned to SubDiv 51 of Rear Admiral Owada Noboru's (former CO of YAMASHIRO) SubRon 7 in Vice Admiral Takagi Takeo's (39)(former CO of MUTSU) Sixth Fleet (Submarines).

15 May 1944:
Departs Kure for Truk via Saipan.

24 May 1944:
Arrives at Saipan.

26 May 1944:
Departs Saipan for Truk.

31 May 1944:
Arrives at Truk.

4 June 1944:
Departs Truk to join a patrol line N of New Ireland.

13 June 1944: Operation A-GO: The Defense of the Marianas:
In Tokyo, the CINC, Combined Fleet, Admiral Toyoda Soemu (former CO of HYUGA), activates A-Go and orders Vice Admiral Takagi Takeo (former CO of MUTSU), CINC, Sixth Fleet to redeploy his boats to the Marianas. From his headquarters on Saipan, Takagi orders all available submarines to deploy E of the Marianas.

14 June 1944:
LtCdr Enomoto receives an order to proceed to a new position S of Guam at flank speed.

15 June 1944: American Operation "FORAGER" - The Invasion of Saipan:
Vice Admiral (later Admiral) Richmond K. Turner's Task Force 52 lands Marine LtGen Holland M. Smith's V Amphibious Corps on Saipan. Communications between Takagi's Advance Expeditionary Force (Sixth Fleet) are disrupted by the invasion. Command of the Sixth Fleet's submarines passes to Rear Admiral Owada at Truk. He orders most of the Sixth Fleet's submarines, including RO-117, to withdraw from the Marianas.

16 June 1944:
Reassigned to "C" patrol unit with RO-113, RO-114 and RO-115. Ordered to assume a new position SE of Tinian, in the area between RO-111 and RO-113.

17 June 1944:
350 miles SE of Saipan. Lt William B. Bridgeman's Consolidated PB4Y-1 "Liberator" of VB-109, based at Eniwetok, makes radar contact with a surfaced submarine. At 0338, Bridgeman's crew attacks and sinks RO-117 at 11-05N, 150-31E.

22 June 1944:
LtCdr Enomoto is ordered to return to Truk, but RO-117 does not respond.

12 July 1944:
Presumed lost with all 55 hands in the Saipan area.

10 August 1944:
Removed from the Navy List.

Authors' Note:
Special thanks for assistance in researching the IJN officers mentioned in this TROM go to Mr. Jean-François Masson of Canada and Matt Jones of the USA. Thanks also go to Dr. Higuchi Tatsuhiro of Japan Steve Eckardt of Australia.

- Bob Hackett and Sander Kingsepp.

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