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

IJN Submarine RO-108:
Tabular Record of Movement

© 2001-2017 Bob Hackett & Sander Kingsepp
Revision 4

20 April 1942:
Kobe. Laid down at Kawasaki Jukogyo K.K. as a 525-ton (standard) Kaisho (KS) Type submarine No. 218.

25 September 1942:
Redesignated RO-108 and provisionally attached to Sasebo Naval District.

26 October 1942:
Launched as RO-108.

16 March 1943:
Lt (Cdr, posthumously) Arai Jun (63)(former torpedo officer of I-158) is appointed Chief Equipping Officer (CEO). [1]

20 April 1943:
Completed and attached to the Sasebo Naval District. Assigned to Kure SubRon for working-up. Lt Arai Jun is the CO.

1 August 1943:
Reassigned to Rear Admiral (later Vice Admiral) Harada Kaku's (former CO of CVS CHIYODA) SubRon 7.

11 August 1943:
Departs Yokosuka for Rabaul.

16 August 1943:
Arrives at Rabaul.

23 August 1943:
Departs Rabaul on her first war patrol to the area SE of San Cristobal.

1 September 1943:
Reassigned to Captain (Rear Admiral, posthumously) Kato Ryonosuke's (48) SubDiv 51.

4 September 1943: Allied Operation "POSTERN" - The Invasion of Lae, New Guinea:
Rear Admiral (later Vice Admiral) Daniel E. Barbey's Task Force 76 lands the Australian 9th Division on the Huon Peninsula, near Lae.

16 September 1943:
Returns to Rabaul.

23 September 1943:
Departs Rabaul on her second war patrol off Finschafen, New Guinea.

30 September 1943:
Lt Arai detects an enemy convoy but fails to attain a favorable firing position.

3 October 1943:
Huon Gulf, 30 miles E of Morobe outpost. Cdr Carlton R. Adams' (USNA '30) USS HENLEY (DD-391) is conducting an offensive ASW sweep with REID (DD-369) and SMITH (DD-378). Shortly before sunset their propeller noises and intermittent sonar "pings" are picked up by the soundman of RO-108, patrolling in the vicinity. Lt Arai commences a submerged approach and reaches a firing position without being observed. At about 1812 RO-108 fires a salvo of four torpedoes at overlapping targets.

SMITH spots three inbound torpedo wakes and combs them, so that one torpedo passes 500 yds to port and the other 200 yds to starboard. HENLEY also evades two torpedoes, but a third hits her port side, explodes in her No. 1 fireroom, destroys her boilers and breaks her keel.

HENLEY's crew abandons ship. At 1829 she breaks in half and sinks, stern first, at 07-40S, 148-06E; one officer and 14 men are lost, 8 officers and 44 sailors injured. During the next seven hours REID and SMITH make several determined but unsuccessful counter-attacks.

11 October 1943:
RO-108 returns to Rabaul. Lt Arai is credited with the sinking of two detroyers.

12 October 1943: Air Raid on Rabaul:
Rabaul. LtGen (later General) George C. Kenney's 5th Air Force hits Rabaul with the biggest raid made up to then in the Pacific war. 349 aircraft, including 87 B-17 and B-24 bombers, 114 B-25 strafers, 12 RAAF "Beaufighters" and 125 P-38 "Lightning" fighters and others from New Guinea and Australia hit Rabaul's airfields and its Simpson harbor.

I-36, I-38, I-176, I-177, RO-105 and RO-108 are moored in deep water. USAAF and RAAF aircraft bomb the harbor. When the attack begins, most of the submarines including RO-108 submerge to safety. I-180, undergoing repairs, receives heavy damage as a result of a direct bomb hit.

23 October 1943:
Departs Rabaul on her first supply run to Sarmi, New Guinea.

24 October 1943:
Arrives at Sarmi, unloads her cargo, then departs.

26 October 1943:
Diverted to patrol off Lae.

9 November 1943:
Returns to Rabaul.

20 November 1943:
Departs Rabaul on her second supply run to Sarmi.

21 November 1943:
Arrives at Sarmi, unloads her cargo, then patrols off Cape Merkus (Arawe), New Britain.

4 December 1943:
Returns to Rabaul.

14 December 1943:
Departs Rabaul on her third supply run to Sarmi.

17 December 1943:
Bismarck Sea, NE of Long Island (04-28S, 147-22E). Around 0114 while recharging batteries on the surface, RO-108 is attacked by a PBY-5A "Catalina" flying boat from VP-52, and receives serious damage. After the crew of the "Catalina" observes the submarine going down by the stern they claim her as sunk. Lt Arai cancels his mission and returns to Rabaul. [2]

20 December 1943:
Departs Rabaul for Sasebo.

1 January 1944:
Arrives at Sasebo for repairs and an overhaul.

20 January 1944:
Lt (LtCdr, posthumously) Obari Kanichi (65)(former torpedo officer of I-32) is appointed CO.

7 March 1944:
Departs Sasebo for Truk.

16 March 1944:
Arrives at Truk.

18 March 1944:
Departs Truk on her third war patrol to patrol N of the Admiralty Islands.

20 March 1944:
Reassigned to the "A" patrol unit.

29 March 1944:
Returns to Truk.

12 April 1944:
Departs Truk her on fourth war patrol to patrol S of the islands.

3 May 1944:
Returns to Truk.

16 May 1944:
Departs Truk on her fifth war patrol to form a picket line to warn of American invasion forces approaching the Palaus.

18 May 1944:
The U.S. Navy intercepts radio traffic that indicates the Japanese have established a new submarine picket "NA line" between Truk and the Admiralty Islands to intercept the American carriers. LtCdr Walton B. Pendelton's USS ENGLAND (DE-635) departs Purvis Bay, off Florida Island, Solomons with LtCdr James Scott's USS RABY (DE-698) and LtCdr Fred W. Just's GEORGE (DE-697) as a hunter-killer group to attack the NA line.

26 May 1944:
The three destroyer-escorts are patrolling 110 miles NE of Seeadler Harbor, Manus Island. At 2303 (Z-11), RABY makes a SL radar contact at 15,000 yds. ENGLAND also makes radar contact and closes. At 2314 when the range is down to 4,100 yds, the target - a submarine heading NE at 11 knots - dives. At 2319, ENGLAND makes sonar contact at 1,650 yds. RABY makes an unsuccessful attack run against the submarine, now heading 150 (T) at the depth of 250 ft, making 2-3 knots. At 2323, Pendelton fires a barrage of twenty-four Mark 10 "Hedgehog" projector charges. Eleven seconds later 4-6 detonations are observed, followed by several minor underwater explosions and rumbling noises.

The next morning, the sea is littered with debris and a patch of diesel oil at 00-32S, 148-35E. Pieces of deck planking, a fragment of a chronometer case, two bottle corks and numerous pieces of insulating material are recovered.

25 June 1944:
Presumed lost with all 53 hands.

10 August 1944:
Removed from the Navy List.

Authors' Notes:
[1] Boyd and Yoshida (1995) identify the officer in question as Arai Atsushi. The Japanese Navy List of 1937, however, identifies him as Arai Jun.

[2] Older sources identify VP-52's target as I-179, lost in a diving accident five months earlier.

Thanks for assistance in researching the IJN officers mentioned in this TROM go to Mr. Jean-François Masson of Canada. Thanks also go to Dr. Higuchi Tatsuhiro of Japan.

– Bob Hackett and Sander Kingsepp.

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