YUSOSEN!
(IRO in warime camoflague scheme)
IJN IRO:
Tabular Record of Movement
© 2006-2024 Bob Hackett, Berend van der Wal and Peter Cundall.
Revision 11
26 March 1920:
Named special mission ship IRO (IROU) under Ta No. 31.
Assumed homeport is the Kure Naval Base under order No. 70.
1 April 1920:
Rated as a special duty ship transport ship under order No. 40.
10 September 1920:
IRO is allotted signal code GQUD under order No. 154.
2 September 1921:
Osaka. Laid down at Osaka Iron Work's Sakurajima yard as a NOTORO class 14500 tons transport ship for the Ministry of Navy.
1 August 1922:
Cdr Iwazawa Yasuguro (30) is appointed Chief Equipping Officer (CEO).
5 August 1922:
Launched as IRO.
27 September 1922:
Departs Osaka. Arrives at Kobe later this day.
27 September ~ 5 October 1922:
In drydock.
5 October 1922:
Departs Osaka for sea trials of the coast of Awaji. Arrives back at Osaka later that day.
12 October 1922:
Departs Osaka for off the coast of Awaji. Arrives back at Osaka later this day.
30 October 1922:
Osaka. Completed. Rated as a special service ship with Kure Naval Base as homeport under order No. 363.
Cdr Iwazawa Yasuguro is appointed Commanding Officer (CO).
4 November 1922:
Departs Osaka.
11 November 1922:
Arrives at Kure.
14 November 1922:
Departs Kure.
15 November 1922:
Arrives at Tokuyama.
17 November 1922:
Departs Tokuyama.
20 November 1922:
Arrives at Yokosuka.
25 November 1922:
Departs Yokosuka.
28 November 1922:
Arrives at Kure.
9 December 1922:
Departs Kure.
21 December 1922:
Arrives at Tarakan, Borneo, Netherlands East Indies (now Kalimantan, Indonesia).
25 December 1922:
Departs Tarakan for Tokuyama.
10 March 1923:
Receives instructions for partial changes to the hawser under order No. 797.
10 November 1923:
Cdr Mizuno Kumao (31) is appointed CO.
1 July 1924:
Cdr (later Rear Admiral) Tomioka Aijiro (32) is appointed CO.
10 November 1924:
Cdr (later Rear Admiral) Mihori Denzo (32)(former CO of NOJIMA) is appointed Commanding Officer.
13 November 1924:
Arrives at Tokuyama.
14 November 1924:
Departs Tokuyama.
18 November 1924:
Arrives at Yokosuka.
19 November 1924:
Departs Yokosuka.
24 November 1924:
Arrives at Ominato.
24 ~ 30 November 1924:
Offloads heavy oil.
30 November 1924:
Departs Ominato.
1 December 1924:
Cdr Mihori is promoted Captain.
7 December 1924:
Arrives at Kure.
11 December 1924:
Departs Kure.
12 December 1924:
Arrives at Tokuyama.
12 ~ 14 December 1924:
Loads heavy oil.
14 December 1924:
Departs Tokuyama.
15 December 1924:
Arrives at Sasebo.
15 ~ 17 December 1924:
Offloads heavy oil.
17 December 1924:
Departs Sasebo.
18 December 1924:
Arrives at Tokuyama.
18 ~ 19 December 1924:
Loads heavy oil.
During the large scale maneuvres the sling equipment for refueling at sea was incorporated into the equipment to be prepared for the exercise instruction on storage for the Kure Naval Arsenal under order No. 3827.
Departs Tokuyama.
20 December 1924:
Arrives at Sasebo.
20 ~ 22 December 1924:
Offloads heavy oil.
22 December 1924:
Departs Sasebo.
23 December 1924:
Arrives at Kure.
15 January 1925:
Departs Kure.
26 January 1925:
Arrives at Tarakan.
26 ~ 28 January 1925:
Loads heavy oil.
28 January 1925:
Departs Tarakan.
10 February 1925:
Arrives at Tokuyama.
10 ~ 12 February 1925:
Offloads heavy oil and then loads heavy oil.
12 February 1925:
Departs Tokuyama.
14 February 1925:
Arrives at Hitonose, Kure.
14 ~ 21 February 1925:
Offloads heavy oil thereafter shifts anchor.
21 February 1925:
Departs Kure.
4 March 1925:
Arrives at Tarakan.
4 ~ 6 March 1925:
Loads heavy oil.
6 March 1925:
Departs Tarakan.
11 March 1925:
Arrives at Manila, Philippines.
14 March 1925:
Departs Manila.
22 March 1925:
Arrives at Tokuyama.
22 ~ 23 March 1925:
Offloads heavy oil.
23 March 1925:
Departs Tokuyama.
24 March 1925:
Arrives at Kure.
29 March 1925:
Departs Kure.
1 April 1925:
Arrives at Maizuru.
1 ~ 3 April 1925:
Offloads heavy oil.
3 April 1925:
Departs Maizuru.
15 April 1925:
Arrives at Tarakan.
15 ~ 17 April 1925:
Loads heavy oil.
17 April 1925:
Departs Tarakan.
28 April 1925:
Arrives at Tokuyama.
29 April 1925:
Departs Tokuyama.
30 April 1925:
Arrives at Kure.
1 May 1925:
Rated as the 4th Reserve Special Service Ship under order No. 123.
10 July 1925:
Captain Mihori assumes "paper" command of survey ship YAMATO as an additional duty.
18 September 1925:
Cdr Ogata Saburo (31) is appointed CO.
1 December 1925:
In service as a reserve special service ship under order No. 321.
5 March 1926:
Capt Suzuki Isamu (32) is appointed CO.
20 May 1926:
Capt Kobayashi Susumo (32) is appointed CO.
15 October 1926:
Cdr (later Rear Admiral) Tachibana Hajime (33) is appointed CO. Rated as the 1st Reserve Special Service Ship under order No. 269.
19 November 1926:
Classified as a special service ship, SHIRETOKO class transport ship under order No. 239.
1 December 1926:
Cdr Tachibana is promoted Captain.
31 March 1927:
Rated as the 1st reserve special service ship under order No. 88.
One motorboat loaned to special service ship ONDO until the end of March 1928 under telegram No. 61.
1 April 1927:
Captain (later Rear Admiral) Sezaki Nihei (32), CO of SETTSU, assumes "paper" command of IRO.
1 May 1927:
Rated as the 4th reserve special service ship under order No. 160. The post of CO is vacant.
2 December 1927:
Receives instructions regarding the reinforcement and construction of a fresh water storehouse under telegram No. 3831.
20 April 1928:
The motorboat returns from special service ship ONDO.
July 1928:
Loanes one motorboat to the light cruiser TENRYU until mid December 1928 under telegram No. 211.
13 November 1928:
Receives approval for extension of the motorboat loan period under telegram No. 3835 No. 2.
22 May 1929:
Loanes one motorboat to the light cruiser JINTSU under telegram No. 155.
3 June 1929:
Receives instructions for the reinforcement and construction of the fresh water storehouse. Completion date is changed to the end of November 1930 under telegram No. 1985.
5 November 1929:
The motorboat returns from light cruiser JINTSU.
23 December 1930:
Receives instructions for the loan and installation of one motorboat to the light cruiser SENDAI under telegram No. 4155.
18 October 1933:
Her call sign changes to JWGD under signal code revision notice No. 127.
8 January 1934:
Receives instructions for the loan of the sounding gauge and accessoires to the special service ship ERIMO under telegram No. 24.
21 February 1938:
Captain (Rear Admiral, posthumously) Sugimoto Michio (41) (CO of TOKIWA, assumes "paper" command of IRO.
15 April 1938:
Captain (later Rear Admiral) Ishizaki Noboru (42)(former CO of SATA) is appointed CO.
15 December 1938:
Captain (later Rear Admiral) Asakura Bunji (44) is appointed CO. Captain Ishizaki is reassigned as the Chief Instructor of the Submarine School.
1 September 1939:
Captain (later Rear Admiral) Horie Giichiro (43)(former XO of YAKUMO) is appointed CO. Captain Asakura is reassigned as an instructor at the Naval Academy.
15 November 1939:
Captain (later Rear Admiral) Nishina Kozo (44) is appointed CO. Captain Horie is reassigned as CO of KAKO.
10 March 1940:
Captain (later Rear Admiral) Takahashi Yuji (44) is appointed CO. Captain Nishina is reassigned to the Naval Shipbuilding Command.
15 October 1940:
Captain (Vice Admiral, posthumously) Inoguchi, Toshihira (46) is appointed CO. Captain Takahashi is reassigned as CO of TENRYU.
24 May 1941:
Capt Mizuguchi Hyoe (46) is appointed CO. Captain Inoguchi is reassigned as the Chief Instructor at the Gunnery School. In Oct '44, he is KIA as CO of MUSASHI.
1 September 1941:
Cdr (Rear Admiral, posthumously) Matsuda Takatomo (45) (former XO of NAKA) is appointed CO.
31 October 1941:
IRO is assigned to the 4th Fleet.
20 November 1941:
Departs Sasebo.
1 December 1941:
Her call sign changes to JGHQ under signal code revision notification No. 369.
2 December 1941: Operation "Z":
The coded signal "Niitakayama nobore (Climb Mt. Niitaka) 1208" is received from the Combined Fleet. It signifies that hostilities will commence on 8 December (Japan time).
4 December 1941:
Departs Kwajalein, Marshalls.
7 December 1941:
Receives ‘Wake Island’ invasion force order No. 3:
Depart on the 9th at an appropiate time and act according to separate orders.
Receives ‘Wake Island’ invasion force order No. 4:
1. Advance to Bikini, Marshalls and wait till December 10th.
2. Further instruction on action will be given at a later date unless there is a special order. Act to reach Bokak Island, Bokak Atoll, Marshalls at 0600 on the 13th.
8 December 1941: The Invasion of Wake Island:
Receives ‘Wake Island’ invasion force order No. 7:
1. Depart at an opportune time ahead of the 18th Squadron in the afternoon of the 8th and advance to Bikini and wait.
2. Subsequent actions will be instructed at a later date. Unless there are special orders proceed so that you reach Bokak Island at 0600 on the 13th.
IRO departs Kwajalein to support the operations against Wake Island. Arrives at Bikini later this day.
Rear Admiral (Vice Admiral, posthumously) Kajioka Sadamichi's (39) (former CO of KISO) Wake Island Attack Force departs Roi-Namur, Kwajalein with CruDiv 18's TATSUTA and TENRYU, DesRon 6's light cruiser YUBARI, DesDiv 29's OITE and HAYATE, DesDiv 30's KISARAGI, MUTSUKI, YAYOI and MOCHIZUKI, two converted destroyer transports, submarine depot ship JINGEI and transports KONGO and KINRYU MARUs.
11 December 1941:
YUBARI and three destroyers close to within 4,500 yards of Wake Island to bombard American positions. At 0615, Marine 1st Lt Clarence A. Barninger's Battery "A" 5-inch guns open fire. YUBARI is straddled, but not hit. She opens the range to 5,700 yards, and is straddled twice more, but not hit.
Two miles SW of Wake Island. HAYATE, OITE and ASANAGI close to bombard Wilkes Island. HAYATE takes three direct hits from salvos of Marine 2nd Lt John A. McAlister's Battery "L" 5-inch guns. At 0652, HAYATE blows up and sinks with her entire crew of 168 at 19-16 N, 166-37 E. Battery "L" also scores a near-miss that damages OITE. DesDiv 30's YAYOI, MUTSUKI and KISARAGI close to bombard both Wilkes and Peale Islands. 1st Lt Woodrow W. Kessler's Battery "B" 5-inch guns on Peale open fire and score a hit on YAYOI.
30 miles SW of Wake. At 0724, USMC Grumman F4F "Wildcats" strafe TENRYU and damage three torpedoes on her deck. A Wildcat strafes TATSUTA and hits her radio shack with machine-gun fire.
Captain Henry T. Elrod, USMC, hits KISARAGI with a 100-lb. bomb that probably detonates her depth charges. At 0731, she blows up and sinks with her entire crew of 150 at 18-55 N, 166-17 E.
That morning, a dejected Rear Admiral Kajioka orders his Attack Force to return to Kwajalein.
Receives 6th Torpedo Squadron secret wireless No. 264:
Head to Kwajalein. Transfer oil from SHIRETOKO and head to Roi, Kwajalein Atoll, Marshalls as quickly as possible.
Departs Bikini. Arrives at Kwajalein later that day.
11 ~ 13 December 1941:
Departs Kwajalein.
13 December 1941:
Arrives at Roi, Kwajalein with auxiliary gunboat SHOEI (MATSUEI) MARU (1877 gt). Receives heavy fuel oil from Naval tanker SHIRETOKO. Departs Roi for Kwajalein.
18 December 1941:
Departs Kwajalein.
28 December 1941:
Arrives at Yokosuka.
5 January 1942:
Departs Yokosuka.
14 January 1942:
Arrives at Truk, Carolines.
15 January 1942:
Receives South Seas Force wireless order No. 50:
Depart at the earliest possible time after completing resupply at Truk and reach approximately 1° north latitude, 140° 45 minutes east longitude by 0600 on the 20th.
Resupply the 6th Squadron as determined by the 6th Squadron and in the afternoon as determined by the commander of the 18th Squadron.
Arrive at Kavieng, New Ireland, Bismarcks (Now Papua, New Guinea) around Z day. If arrival is difficult wait at sea.
Resupply of the R (Bismarck Archipelago) invasion force detachment and the 6th Squadron will be entrusted to the supply of the R invasion force detachment and the 6th Squadron.
Actions after the completion of the above resupply will be ordered separately.
17 January 1942:
Departs Truk.
20 January 1942:
At 0500, at 01-00N 147-45E meets up with Crudiv6. At 0700, starts refueling Crudiv6. Supplies AOBA with 343t oil, KAKO with 355t oil, KINUGASA with 341t oil and FURATAKA with 384t oil. At 1500, the refueling of CruDiv6 is completed.
23 January 1942: Operation "O"- The Invasion of Rabaul and Kavieng:
Provides refueling support for the invasion landings.
24 January 1942:
At 0600, begins refueling CruDiv6. Supplies AOBA with 414t oil, KAKO with 437t oil, KINUGASA with 440t oil and FURATAKA with 455t oil. At 1300, refueling of CruDiv6 is completed.
28 January 1942:
At 0800 arrives at Rabaul, New Britain, Bismarck Islands, Australia (now Papua New Guinea). At 0930 begins loading auxiliary oiler KAIJO MARU No. 2 GO’s residual heavy oil and then supplies the destroyers ASANAGI, and YUZUKI with heavy oil.
29 January 1942:
Supplies the destroyers UZUKI, KIKUKI and YUZUKI with heavy oil.
30 January 1942:
At 0830 begins refueling CruDiv6. Supplies AOBA with 500t oil, KAKO with 500t oil, KINUGASA with 500t oil and FURATAKA with 500t oil. At 1430, the refueling of CruDiv6 is completed.
31 January 1942:
Replenishes auxilairy netlayer KOTOBUKI MARU No. 5, auxiliary subchasers TAMA MARU No. 8 and TOSHI MARU No. 3 with water.
1 February 1942:
Replenishes auxiliary minesweepers TAMA MARU, TAMA MARU No. 2, HAGOROMO MARU and N OSHIRO NO. 2 GO with water. Rated as a R Area Force Resupply Unit under South Seas Force wireless order No. 66 from 29 January.
2 February 1942:
At 1330, replenishes destroyer OITE, at 1400 replenishes destroyuer ASANAGI and at 1450 replenishes destroyer YUNAGI.
4 February 1942:
At 0900, replenishes light cruisers YUBARI and at 1240 replenishes destroyer MOCHIZUKI. Departs Rabaul later that day.
17 February 1942:
Arrives at Yokosuka.
24 February 1942:
Departs Yokosuka.
11 March 1942:
Arrives at Rabaul.
14 March 1942:
At 1430, Refuels destroyer OITE.
15 March 1942:
From 0530 until 0910 refuels light cruiser YUBARI with 1,364 tons fuel oil. Departs Rabaul later this day.
29 March 1942:
Arrives at Yokosuka.
1 April ~ 8 April 1942:
Loads munitions.
9 April 1942:
Departs Yokosuka.
18 April 1942:
Arrives at Truk.
23 April 1942:
Assigned to the MO (Port Moresby) invasion force under secret south Seas Force order No. 13.
Assigned to the supply corps under secret MO invasion force order No. 1.
24 April 1942:
Departs Truk escorted by destroyer KIKUZUKI and YUZUKI.
25 April 1942:
Assigned to the supply corps under secret RY (Ocean Nauru) invasion force order No. 1.
27 April 1942:
Arrives at Rabaul. Engages in replenishment of fleet units.
30 April 1942: Operation “MO” – The Invasions of Tulagi and Port Moresby:
Rabaul. Rear Admiral Kajioka's Port Moresby Attack Force departs with DesRon 6's YUBARI, DesDiv 29’s ASANAGI, OITE, DesDiv 30’s MUTSUKI, MOCHIZUKI and YAYOI and a patrol boat escorting Rear Admiral (later Vice Admiral) Abe Koso's (40) (former CO of HIEI) Transport Force of five Navy and six Army transports, oilers GOYO and HOYO MARUs, repair ship OJIMA, escorted by mine-sweepers W-20, HAGOROMO MARU, NOSHIRO MARU No. 2, FUMI MARU No. 2 and mine layer TSUGARU towards the Jomard Pass in the Louisiade Archipelago.
Receives MO invasion force wireless order No. 4:
1. The covering force commander will escort IRO from Rabaul to Queen Carola harbor, Buka Island, Solomons by plane.
2. IRO’s anchorage at Queen Carola harbor will be 320° and 1500m from the western end of Yapura (Harbor) Island.
1 May 1942:
Cdr Matsuda Takatomo is promoted to Captain.
3 May 1942:
Receives RXB (Tulagi, Gavutu, Mokambo) invasion force wireless order No. 2:
1. After completing the supply mission at Queen Carola harbor IRO will head to Kavieng by 0800 on May 8th.
2. The 23rd Destoyer Squadron minus the 2nd platoon will escort the IJN transport AZUMASAN MARU scheduled to depart on May 4th and after meeting with the RZP (Port Moresby) invasion force will head to Kavieng on May 7th.
3. The commander of the 23th Destroyer Squadron will disengage the YUZUKI en route. She heads to Queen Carola harbor by 14:00 on the 6th and will receive orders from the Captain of IRO to have the ship act as escort until it arrives in Kavieng.
Departs Rabaul.
3 ~ 4 May 1942:
The Attack Force stops briefly at Shortland Islands, Bougainville to setup a seaplane base.
May 1942:
IRO remains at Shortlands as a Station Tanker with KEIJO MARU and elements of the 84th Guard Unit.
4 May 1942:
Receives secret 6th Squadron wireless No. 113:
IRO should immediately advance to Shortland and prepare to supply the MO main force.
After this is completed IRO should act under the direction of the RXB invasion force commander.
Arrives at Queen Carola harbor.
4 ~ 5 May 1942:
Departs Queen Carola harbor for Shortland.
5 May 1942:
Receives RY invasion force wireless order No. 2: 19th Squadron secret wireless No. 436:
1. IRO should immediately return to Rabaul after completing her resupply mission in Shortland.
2. Destroyer UZUKI should receive directions from the Captain of IRO and cover the ship’s return to Rabaul. Then wait in Rabaul.
Shortland Islands Anchorage, Bougainville. CruDiv 6's KINUGASA, AOBA, FURUTAKA and KAKO arrive and refuel from IRO as well as carrier SHOHO.
6 May 1942:
Departs Shortland with IJN oiler OMUROSAN MARU for Rabaul escorted by destroyer UZUKI.
7 May 1942:
Receives 4th Fleet secret wireless No. 369:
IRO, IJN oiler OMUROSAN MARU and destroyer UZUKI should advance 100 nautical miles southwest of Shortland and wait.
Receives 4th Fleet secret wireless No. 377:
IRO, IJN oiler OMUROSAN MARU and destroyer UZUKI will conveniently stop at Shortland and OMUROSAN MARU’s fuel will be transferred to IRO.
Receives 6th Squadron secret wireless No. 138:
1. IRO will reach RXE (Shortland) at 1100 225° and 100 nautical miles on the 8th and will replenish the 6th’s Squadron 1st Platoon and will proceed as planned. After the main force has completed the above replenishment it will join the invasion force.
2. HOYO MARU will enter Deboyne, Teritory of New Guinea, Australia (now Papua New Guinea) by sunset on the 8th and prepare to replenish the RZP invasion force.
At 0954 IRO, OMUROSAN MARU and destroyer UZUKI depart Shortland and head 100 Ri in a SW direction. Later at 1654 they arrive back at Shortland.
8 May 1942:
At 1100 begins refueling cruisers AOBA and KAKO with heavy oil but soon after it stops.
Receives 4th Fleet secret wireless No. 404:
IRO is relieved of its mission of resupplying the RY invasion force. Destroyer UZUKI should immediately return to RR (Rabaul) and resupply should be carried out from the NISSHIN MARU.
Receives 6th Squadron secret wireless No. 146:
1. Stop joining the task force and head north. 6th squadron, 1st platoon, 1430 position 16, course 0, speed 12 knots.
2. The 18th Squadron and the 6th Torpedo Squadron will be resupplied from the IRO or HOYO MARU.
The IRO and HOYO MARU will head to Shortland.
Receives RY invasion force wireless order No. 5:
1. after the IRO finishes resuplying the 6th Squadron 1st Platoon IRO will transfer fuel from the OMUROSAN MARU at Shortland. The personnel transferred and accommodated by the SHOHO are transported by the the OMUROSAN MARU to the supply starting point at 0800 on May 12th. Act so as to reach 1-30S, 158-20E, 12° and 456 nautical miles from Kavieng.
2. Destroyer UZUKI will be assigned to escort the ship under orders of the Captain of the IRO.
Arrives at Shortland.
9 May 1942: The Battle of Coral Sea.
Receives MO invasion force wireless order No. 12:
IRO and HOYO MARU should wait at Shortland.
After the Battle of Coral Sea, Operation MO is canceled and the Attack Force returns to Rabaul.
Some ships sail to Shortland where they are refuelled by HOYO MARU, IRO and OMUROSAN MARU. At 1400, loads heavy oil from the auxiliary oiler OMUROSAN MARU. IRO refuels destroyer HAYASHIO.
10 May 1942:
Departs Shortland.
11 May 1942:
Arrives at Rabaul. From 1040 till 1344 minelayer TSUGARU lies alongside to starboard and is supplied with 401t heavy oil. Hospital ship HIKAWA MARU lies along port side.
13 May 1942:
Departs Rabaul.
18 May 1942:
Arrives at Truk.
20 May 1942:
Minelayer TSUGARU lies alongside and is supplied with heavy oil.
21 May 1942:
Departs Truk.
30 May 1942:
Arrives at Kure. Dry docked for repairs.
22 June 1942:
Undocked. Departs Kure.
23 June 1942:
Arrives at Shikanokawa.
24 June 1942:
Departs Shikanokawa.
4 July 1942:
Arrives at Truk.
6 July 1942:
Departs Truk.
8 July 1942:
Receives south Seas Force wireless order No. 249:
After arriving at Rabaul the HOYO MARU will transfer heavy oil to the R Area Defense Force to its full load as specified by the R (Rabaul) Area Defense Force Commander and then promptly return to Truk.
Transferred to R military district under command of R District Defence Commander and ordered upon arrival at Truk Rabaul to take on heavy oil from HOYO MARU before the latter vessel departs for Truk.
Transferred to R (Rabaul) military district under command of R District Defence Commander and ordered upon arrival at Truk to take on heavy oil from HOYO MARU before the latter vessel departs for Truk.
11 July 1942:
Arrives at Rabaul. Likely loads all remaining heavy oil from HOYO MARU.
16 July 1942:
Receives RZJ (Eastern New Guinia) invasion force order No. 9:
Heavy fuel oil should be loaded from IRO as follows:
1. Minelayer TSUGARU immediately after arriving in the afternoon of the 17th.
2. 18th Squadron, afternoon of the 18th.
3. Destroyer ASANAGI immediately after arriving in the afternoon of the 18th.
17 July 1942:
From 1552 till 1807 minelayer TSUGARU lies alongside and is supplied with 284t heavy oil.
18 July 1942:
In the afternoon scheduled to refuel destroyer ASANAGI and the 18th Sentai on their arrival.
18 ~ 21 July 1942:
Departs Rabaul.
21 July 1942:
Refuels 6th Cruiser Squadron heavy cruisers AOBA and KAKO.
22 July 1942:
Refuels 6th Cruiser Squadron heavy cruisers KINUGASA and FURUTAKA. Arrives at Rabaul.
26 July 1942:
Departs Rabaul.
29 July 1942:
Arrives at Truk.
31 July 1942:
Departs Truk.
2 August 1942:
Arrives at Saipan, Marianas.
6 August 1942:
Departs Saipan.
11 August 1942:
Arrives at Kavieng. Refuels CruDiv 6 consisting of heavy cruisers AOBA, KAKO, KINUGASA and FURUTAKA in Mowe Passage.
12 August 1942:
Departs Kavieng.
13 August 1942:
Arrives at Rabaul.
14 August 1942:
Departs Rabaul likely with IJN aircraft transport LYONS MARU.
18 August 1942:
Arrives at Truk.
22 August 1942:
Captain Matsuda is reassigned to the Yokosuka Naval District. In Feb '44, he is KIA as CO of light cruiser AGANO.
24 August 1942:
Receives 2nd Maritime Escort Fleet order No. 8:
1. The IJN oiler SAN CLEMENTE MARU is scheduled to depart for Rabaul after transferring fuel to the IRO on the 25th.
2. The minesweeper W-22 will provide direct escort to Rabaul.
25 August 1942:
Cdr Sakano Yasaburo (46) is appointed CO.
Takes on fuel from IJN oiler SAN CLEMENTE MARU.
30 August 1942:
Arrives at Jaluit. Remains there throughout September and October.
4 September 1942:
IJN oiler HOYO MARU arrives at Jaluit and transfers fuel to IRO.
4 November 1942:
At 9-00N 155-00E IRO meets up with auxiliary cruiser UKISHIMA MARU which escorts the ship to Truk.
5 November 1942:
Arrives at Truk.
10 November 1942:
Departs Truk with tanker NOTORO escorted by destroyer YUZUKI. At 10 Ri outside the atoll YUZUKI detaches and returns to Truk.
16 November 1942:
Arrives at Jaluit and remains there the rest of the month.
12 December 1942:
Departs Jaluit.
18 December 1942:
Arrives at Saipan.
19 December 1942:
Departs Saipan.
25 December 1942:
Joined by subchaser CH-36 at 31-28N 132-38E and escorted to Fukajima.
26 December 1942:
Arrives at Kure.
14 January 1943:
Departs Kure.
15 January 1943:
Off Saiki. At 1045 joined by subchaser CH-36 and escorted south.
E 16 January 1943:
CH-36 is detached at a point 90 degrees off Toi Misaki.
19 January 1943:
Arrives at Mako, Pescadores (now Magong, Penghu Islands, Taiwan). .
22 January 1943:
Departs Mako.
1 February 1943:
At 7-22N 148-53E destroyer YUNAGI meets up with IRO and escorts the tanker to Truk.
2 February 1943 (or possibly 1 February 1943):
Arrives at Truk.
15 February 1943:
Departs Truk.
20 February 1943:
Arrives at Jaluit.
27 February 1943:
Departs Jaluit escorted by auxiliary gunboat KATORI MARU and auxiliary subchaser SHONAN MARU No. 11. At about 0900, W of Jaluit, IRO is torpedoed by LtCdr Raymond H. Bass' (USNA ’31) USS PLUNGER (SS-179). Hit by one of five torpedoes Bass fires, IRO becomes unnavigable. KATORI MARU tows her to Jaluit with SHONAN MARU No. 11 as escort.
4 March 1943:
Arrives at Jaluit (or alternatively Roi). Departs later this day.
6 March 1943:
Arrives Kwajalein. Undergoes repairs for the next two months.
22 April 1943:
Minelayer TOKIWA and IRO depart Kwajalein at 0558 but both return at 1625.
24 April 1943:
TOKIWA and IRO again depart Kwajalein at 0550 and return at 1337.
27 April 1943:
Captain Kitamura Fumio (47) is appointed CO.
17 May 1943:
Arrives at Roi.
21 May 1943:
At 0630 departs Kwajalein under tow by passenger-cargo ship OKITSU MARU escorted by the destroyer OITE, submarine chaser CH-31 and auxiliary sub-chaser TAMA MARU No. 5. Arrives at Roi later this day.
23 May 1943:
Departs Roi under tow by passenger-cargo OKITSU MARU escorted by destroyer OITE and subchaser CH-31 and auxiliary sub-chaser TAMA MARU No. 5. At some point auxiliary sub-chaser TAMA MARU No. 5 detaches.
E 30 May 1943:
The convoy arrives at Saipan.
1 June 1943:
At 0600 departs Saipan still under tow escorted by auxiliary netlayer SHUKO MARU that returns to Saipan the following day, and destroyer OITE and subchaser CH-31.
8 June 1943:
Receives Kure Defense Squadron wireless order No. 206:
1. IRO is scheduled to arrive at noon at 30-26N, 133-33E on the 9th. Then with a course of 330° and speed of 6.5 knots is scheduled to arrive at Fukushima at noon on the 10th.
2. The 1st Special Sweeping Unit will replenish at Saiki and then be activated at 1800 on the 10th and will sweep 70 nautical miles from Fukashima. After carrying out round trip sweeps on their route they will be tasked with guiding the waterway to the mouth of Saiki Bay.
3. The commander of the Saiki Defense Unit will have two suitable vessels patrol the southern half of the E1 patrol area from early morning on the 10th until they arrive at the IRO.
10 June 1943:
SE of Fuka Island, Oita Ken. At about 0500, IRO, still under tow, is hit by two of four torpedoes fired by LtCdr (later Rear Admiral) Lawrence R. Daspit's' (USNA ’27) USS TINOSA (SS-283) at 31-14N, 132-44E. IRO sustains some flooding to Number 1-6 tanks and her pump room and develops a 13-degree list, but continues under tow. At 0930, at 100-degrees and 20 nautical miles from the Mimitsu lighthouse auxiliary sub chaser DAITON MARU joins the escort.
Auxiliary minesweepers TAKUNAN MARU No. 3 and TAKUNAN MARU No. 8 join as additional escorts at 31-52N, 132-25E.
11 June 1943:
Subchaser CH-31 arrives at Kure.
12 June 1943:
Arrives at Kure. The tow of some 4,600 miles had been completed at an average speed of 5-6 knots through treacherous waters. The crew of OKITSU MARU receives deservedly profuse congratulations.
July ~ November 1943:
Under repair at Kure.
30 November 1943:
Dry docked. While undergoing repairs, an experimental camouflage is painted on replacing the dazzle camouflage previously adopted. The new camouflage consists of dark grey overall, except for bow and stern that are painted light grey to give the impression of a smaller, faster oiler with raked bow and cruiser stern. The camouflage is deemed successful, but is not duplicated elsewhere.
4 December 1943:
Departs Kure.
8 December 1943:
Departs Saeki for Palau in convoy O-803 consisting of IRO and cargo ships FUKKO and TAIAN MARUs escorted by torpedo boat HATO and minelayer YURISHIMA. TAIAN MARU is towing a crane platform.
10 December 1943:
At 1000, YURISHIMA is detached from the convoy.
17 December 1943:
Receives transport ship camouflage painting instruction for second color under secret instruction No. 6258.
18 December 1943:
Arrives at Palau. Loads 8,000-tons of crude oil.
23 December 1943:
Departs Palau in convoy 2516 also consisting of tankers NIPPON and KENYO MARUs escorted by destroyers HAYANAMI and WAKATAKE. At 1622 destroyer HAYANAMI fires two warning shots.
25 December 1943:
At dawn at 0800, HAYANAMI is detached.
28 December 1943:
Arrives at Tarakan.
2 January 1944:
At 1600, IRO departs Tarakan with a cargo of refined oil with cargo ship TOSHO MARU, escorted by destroyer WAKATAKE.
4 January 1944:
At 1900, arrives at Balikpapan, Borneo, Netherlands East Indies (now Kalimantan, Indonesia). Loads a cargo of crude oil.
21 January 1944:
At 0945, IRO departs Balikpapan in convoy O-103 consisting of oilers SATA and JAMBI MARU escorted by patrol boat PB-36 and subchaser CH-37 and auxiliary submarine chaser CHa-41.
22 January 1944:
At 1435, aircraft discover things that seems to be hostile and dangerous. PB-36 is sent to investigate these. At 1524, PB-36 arrives at the spot indicated by the aircraft and drops 8 depth charges without result. At 1600, PB-36 ends her investigation. At 1820, PB-36 rejoins the convoy. At 2240, at the Tarakan latitude JAMBI MARU detaches and heads towards Tarakan.
28 January 1944:
At 1350, arrives at Palau west entrance.
2 February 1944:
At Palau auxiliary subchaser TAMA MARU No. 7 lies alongside to starboard.
Replenishes the destroyers YAMAGUMO and AKIKAZE.
5 February 1944:
At Palau bunkers heavy cruiser KUMANO.
14 February 1944:
At Palau bunkers heavy cruiser KUMANO.
19 February 1944:
Palau. Provisioned by auxiliary storeship KITAKAMI MARU.
21 February 1944:
Departs Palau with tanker HISHI MARU No. 2 and possibly others.
27 February 1944:
Arrives at Tarakan.
4 March 1944:
Attached to the Combined Fleet, Central Pacific Fleet, 4th Fleet.
Departs Tarakan.
6 March 1944:
Arrives at Balikpapan.
9 March 1944:
Departs Palau with IJN oiler OSE (ex Dutch GENOTA) escorted by CruDiv 5's MYOKO and HAGURO and destroyer SHIRATSUYU.
12 March 1944:
Arrives at Balikpapan.
15 March 1944:
At 0730, departs Balikpapan for Palau in convoy O-507 consisting of three echelons of seven ships escorted by destroyers HARUSAME and SHIRATSUYU, patrol boat PB-36, subchaser CH-6 and auxiliary subchaser CHa-52.
The first echelon consists of IRO and passenger-cargo NAGISAN MARU and oiler HISHI MARU No. 2. The second echelon consists of oilers TSURUMI and KYOEI MARU and cargo ship RAIZAN MARU and the third echelon consists only of cargo ship HOKUTAI MARU.
16 March 1944:
At 1530, destroyer MICHISHIO joins the convoy and the other escorts, except for PB-36 escorting IRO, depart.
17 March 1944:
At 0200 destroyer MICHISHIO stops escorting and returns to port.
20 March 1944:
At 0910, auxiliary subchasers CHa-51 and CHa-53 join the escort.
21 March 1944:
At 0930 auxiliary subchaser Cha 27 joins the escort.
22 March 1944:
LtCdr (later Cdr) John A. Scott's (USNA ’28) USS TUNNY (SS-282) SJ radar picks up a large convoy. At daybreak, Scott is maneuvering to gain an attack position when his radar picks up a destroyer at 14,000 yards. The destroyer sights the submarine and challenges USS TUNNY with a blinker. Scott ducks into a nearby rain squall and continues to close on the surface in conditions of poor visibility. Through the haze, he makes out a group of oilers and cargo ships.
Scott sets up and fires a full bow spread of six-torpedoes at two cargo ships at 07-22N, 132-08E. He and his crew see and hear hits on both, but suddenly, a small oiler, probably KYOEI MARU, appears out of the gloom and almost collides with USS TUNNY.
Scott sets up on destroyer MICHISHIO moving at high speed across USS TUNNY’s stern. He fires four Mark-18 electric torpedoes, then crash dives as depth charges from a trawler explode on his port quarter. During the next four hours, IRO is hit in the bow, forward of the bulkheads. PB-36 remains with IRO with oiler TSURUMI also standing by till 0900, while MICHISHIO and newly arrived destroyers HARUSAME and SHIGURE search for the submarine. The Japanese drop 87 depth charges on USS TUNNY, but without effect.
After completing emergency repairs IRO departs for Palau unescorted with a speed of 6 knots. At 9.25 PB-36 stops mopping up, heads towards IRO and escorts her to Palau.
23 March 1944:
At 1800 IRO limps into Palau at 6 knots.
24-25 March 1944:
Transfers part of fuel cargo to heavy cruiser TAKAO.
30 March 1944: American Operation “Desecrate One”:
Palau. The anchorage is attacked by F6F "Hellcats", SBD "Dauntless", TBF "Avenger" and SB2C "Helldivers" of Task Group 58. 1's USS ENTERPRISE (CV-6), USS BELLEAU WOOD (CVL-24) and USS COWPENS (CVL-25), TG 58. 2's USS BUNKER HILL (CV-17), USS HORNET (CV-12), USS MONTEREY (CV-26) and USS CABOT (CVL-28) and TG 58. 3's USS YORKTOWN (CV-10), USS LEXINGTON (CV-16), USS PRINCETON (CVL-23) and USS LANGLEY (CVL-27).
31 March 1944:
Palau Harbor. TF 58's planes find and attack IRO anchored in a sheltered lagoon close to Koror, Peleliu. She sustains a direct bomb hit in the engine-room and is set afire. Of 250 soldiers on board, 200 survive, but Captain Kitamura is KIA. He is promoted Rear Admiral, posthumously.
17 April 1944:
IRO burns for days. On this day, she sinks in 130 feet of water. Her funnel lies horizontally where it falls across the deck.
10 May 1944:
Removed from the Navy List under order No. 657.
Authors' Note:
Photo credit goes to Matthew Jones. Grateful thanks to Mr. Gilbert Casse of France, Berend van der Wal of Netherlands and the late John Whitman of Virginia, USA and Mr. Gengoro Toda of Japan for additional assistance.
- Bob Hackett and Peter Cundall.
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