SENSUIKAN!

© 2001-2003 Bob Hackett & Sander Kingsepp

25 July 1942:
The RO-103 is under construction at Kure. Lt Sakamoto Kaneyoshi (former Torpedo/Division Officer of I-1), Chief Equipping Officer for the RO-100, is posted additional duty as Chief Equipping Officer for the RO-103.

29 August 1942:
Lt Fujita Hidenori is posted Chief Equipping Officer for the RO-103.

21 October 1942:
The RO-103 is completed, commissioned in the IJN and assigned to Kure SubRon. Lt Fujita is the Commanding Officer.

5 January 1943:
Assigned to Rear Admiral (later Vice Admiral) Harada Kaku's (former CO of CVS CHIYODA) SubRon 7 in SubDiv 13 of Vice Admiral Mikawa Gunichi's (former CO of KIRISHIMA) Eighth Fleet at Rabaul. Departs Kure.

14 January 1943:
Arrives at Truk.

4 February 1943:
Departs Truk.

8 February 1943:
Arrives at Rabaul.

9 February 1943:
Departs Rabaul on her first war patrol with the RO-102 to patrol E of Port Moresby, New Guinea.

16 February 1943:
Lt Ichimura Rikinosuke (former torpedo officer of RO-100) is posted as the next CO of the RO-103.

28 February 1943:
Returns to Rabaul.

2 March 1943: The Battle of the Bismarck Sea:
A convoy of Supply Operation No. 81 under Rear Admiral (later Vice Admiral) Kimura Masatomi (former CO of CA SUZUYA) is en route to Lae, New Guinea with troops of the IJA's 51st Division embarked. Over the next three days, the convoy is bombed and strafed repeatedly by USAAF and RAAF planes. All of the eight transports and cargo vessels in the convoy and four of the eight escorting destroyers are sunk. Hundreds of IJA soldiers in lifeboats, rafts and in the water are machine-gunned by planes and PT boats.

10 March 1943:
Fujita spots an American destroyer. He orders all classified documents dumped in the sea, but the destroyer turns away without spotting the RO-103.

13 March 1943:
The RO-103 is dispatched to rescue survivors of Kimura's convoy.

15 March 1943:
The RO-103 runs aground on an uncharted reef at 08-20S, 150-45E. Fujita signals Rabaul for assistance. The RO-101 is ordered to the scene to tow. The RO-103 dumps food, supplies and torpedoes to lighten the submarine. She breaks free from the reef before the RO-101 arrives.

17 March 1943:
Returns to Rabaul. While in port, Lt Ichimura assumes command. Lt Fujita is later reassigned to command the I-180 on which he is KIA in Apr '44.

30 March 1943: Operation "I-GO" - The Reinforcement of Rabaul.
Admiral (Fleet Admiral, posthumously) Yamamoto Isoroku (former CO of AKAGI), CINC Combined Fleet, orders aircraft from CarDiv 1's ZUIKAKU and the ZUIHO to reinforce Vice Admiral Kusaka Jinichi's (former CO of FUSO) 11th Air Fleet's base at Rabaul. Yamamoto also orders aircraft from CarDiv 2's HIYO and the JUNYO to reinforce the base at Ballale Island, near Buin, Bougainville.

The RO-103 departs Rabaul on her second war patrol for the Guadalcanal area with the RO-102 to support I-GO.

20 April 1943:
Returns to Rabaul.

9 May 1943:
Departs Rabaul to patrol off in an area E of Guadalcanal on her third war patrol.

1 June 1943:
Returns to Rabaul.

12 June 1943:
Departs Rabaul for the Gatukai-San Cristobal area on her fourth patrol.

23 June 1943:
50 nms S of the eastern tip of the San Cristobal Island. Lt Ichimura sights a convoy of three transports protected by three destroyers. He torpedoes and sinks the 7,440-ton USS ALDURA (AK-72) and torpedoes the 7,176-ton "Liberty" ship USS DEIMOS (AK-78), while both are in convoy en route to Guadalcanal in the vicinity of 11-26S, 162-01E at the eastern tip of San Cristobal Island. The DEIMOS, damaged irreparably, is scuttled by the destroyer O'BANNON (DD-450) at 11-35S, 162-08E.

29 June 1943:
While recharging batteries after sunset, Lt Ichimura reports sighting seven enemy ships S of Gatukai Island. These are probably ships of Rear Admiral (later Admiral) Richmond K. Turner's Third Fleet's Amphibious Force.

30 June 1943: American Operation "TOENAILS" - The Invasion of New Georgia, Solomons:
Rear Admiral (later Admiral) Richmond K. Turner's Third Fleet Amphibious Force, supported by land-based aircraft, lands Marines and Army troops on Rendova and other islands in the New Georgia area.

4 July 1943:
Returns to Rabaul.

11 July 1943:
The RO-103 departs Rabaul on her fifth war patrol for the Rendova area.

13 July 1943:
Arrives at her patrol area at Vanga Bay, Vangunu Island.

15-24 July 1943:
Lt Ichimura sights enemy forces three times, but is unable to gain an attack position.

28 July 1943:
N of New Georgia, Bismarck Islands. Ichimura reports his three enemy ship sightings to Rabaul. It is the last signal received from the RO-103.

10 August 1943:
Presumed lost with all 43 hands in the Solomons.*

1 November 1943:
Removed from the Navy List.

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Authors' Notes:
*The circumstances surrounding the loss of the RO-103 remain unknown - perhaps she was sunk by a mine or a PT-boat. Author/historian Kimata Jiro suggests she hit a mine in one of the mine fields laid by USS BREESE (DM-18), PREBLE (DM-20) and GAMBLE (DM-15).

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

– Bob Hackett and Sander Kingsepp.

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