IJN Submarine RO-48:
Tabular Record of
© 2001-2017 Bob Hackett & Sander Kingsepp
17 March 1942:
Laid down Mitsubishi's Kobe Yard as a 960-ton type K6 submarine.
31 July 1943:
Numbered RO-48 and provisionally attached to Maizuru
15 October 1943:
Launched. RO-48 receives a different conning tower,
shaped to reduce the radar incident angle. She is fitted with an E27/Type 3
radar detector prior to the completion.
20 January 1944:
Lt (Cdr, posthumously) Ichitomi Kiyota (63)(former
CO of RO-58) is appointed the Chief Equipping Officer (CEO).
31 March 1944:
Kobe. Completed and attached to Maizuru Naval
District. Assigned to SubRon 11 for working-up. Lt (promoted LtCdr 1 May)
Ichitomi Kiyota is the Commanding Officer.
13 June 1944: Operation "A-GO" - The Defense of the Marianas:
Admiral Toyoda Soemu (33)(former CO of HYUGA), CINC, Combined Fleet, activates
A-Go and orders Vice Admiral Takagi Takeo (39)(former CO of MUTSU), CINC, Sixth
Fleet, to redeploy his boats to the Marianas.
15 June 1944: American Operation "FORAGER" - The Invasion of Saipan:
Vice Admiral (later Admiral) Richmond K. Turner's (USNA '08) Task Force 52 lands
Marine LtGen Holland M. Smith's V Amphibious Corps and the invasion begins.
Communications between Takagi's Sixth Fleet on Saipan are
disrupted by the invasion. Command of the Sixth Fleet's submarines passes to
Rear Admiral Owada Noboru (44)(former Co of YAMASHIRO), ComSubRon 7 at Truk. He
orders most of the Sixth Fleet's submarines to withdraw from the Marianas.
3 July 1944:
RO-48 is assigned to SubDiv 34, Sixth Fleet (Submarines).
5 July 1944:
Departs Kure on her first war patrol for her assigned
area off Saipan.
10 July 1944:
Vice Admiral Vice Admiral Miwa Shigeyoshi (39)(former CO
of KINU) at Kure assumes command of the Sixth Fleet from Rear Admiral Owada at
12 July 1944:
Arrives at her assigned area within 200 nms of Saipan.
Receives a new order to stand by to rescue IJN pilots from Tinian.
14 July 1944:
At 2130 (JST) when stationed 30 nms N of Saipan, LtCdr
Ichitomi reports that he had been forced underwater and is in process to change
16 July 1944:
Headquarters, Sixth Fleet orders RO-48 to return.
18 July 1944:
300 miles E of Saipan. Captain W. V. Saunders' USS
HOGGATT BAY's (CVE-75) task group 12.2, a hunter-killer group, is conducting
antisubmarine warfare (ASW) operations off the Marianas. The carrier's radar
picks up a contact on the surface at 21,000 yards.
19 July 1944:
At 0024, Captain Saunders detaches two of his four
screening escorts, LtCdr E. P. Parker's USS WYMAN (DE-38) and REYNOLDS (DE-42),
to investigate the carrier's radar contact. WYMAN closes the range until 0046
when she loses radar contact at 4,000 yards as the contact dives.
WYMAN switches to her sonar and picks up a strong echo at 1,600 yards. At
0051, Parker fires a barrage of twenty-four Mark 10 "Hedgehog" projector
charges, but without results. WYMAN reloads and Parker opens the range, then he
closes for a second attack.
At 0125, Parker fires a second barrage of twenty-four hedgehogs. WYMAN is
rocked by five underwater explosions as the hedgehogs blow the submarine apart.
Parker attempts to regain sonar contact but the sonar's returns indicate that
the contact has been destroyed. The submarine - probably RO-48 - is sunk E of
Saipan at 13-01N, 151-58E. 
10 July 1944:
Presumed lost with all 76 hands off Saipan.
10 October 1944:
Removed from the Navy List.
 Some older sources credit USS GILMER (APD-11) and WILLIAM
C. MILLER (DE-259) with the sinking of RO-48. In reality, their victim was I-55.
Thanks go to Dr. Higuchi Tatsuhiro of Japan.
– Bob Hackett and Sander Kingsepp
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