Japanese Minesweepers

SOKAITEI!
(W-13 scanned from Maru Special, V. 50)

IJN Minesweeper W-15: Tabular Record of Movement
© 2005-2018 Bob Hackett and Peter Cundall
Revision 13

6 April 1933:
Osaka. Laid down at the Fujinagata Zosen shipyard. Her call sign is GQSP.
14 February 1934:
Launched and numbered W-15.
21 August 1934:
Completed and registered in the Kure Naval District.
31 August 1934:
Completed and registered in the Kure Naval District. Attached to the Kure Defence Corps Eleventh Minesweeper Corps.
1 September 1934:
Departs Kure.
6 September 1934:
Departs Sasebo for Kure.
18 October 1934:
Her call sign is changed to JXOD.
15 November 1934:
Assigned Guard boat for the Eleventh Minesweeping Corps.
5 December 1934:
Departs Kure and returns later this day.
14 October 1935:
Departs Kure.
19 October 1935:
At Kure.
1 December 1936:
LtCdr (RAdm, posthumously) Ikeda Akira (50)(former CO of W-16) is appointed the Commanding Officer.
6 April 1938:
An unknown officer assumes command.
10 April 1941:
Attached to the Combined Fleet Third Fleet Second Base Force Eleventh Mineseeper Corps.
10 June 1941:
Takao, Formosa. Assigned to Rear Admiral (later Vice Admiral) Hirose Sueto's (36) (former CO of AOBA) 2nd Base Force of Vice Admiral Takahashi Ibo's (36) (former CO of KIRISHIMA) Third Fleet.
1 December 1941:
Her call sign is changed to JXOP. Departs Sasebo.
4 December 1941:
Arrives at Mako, Pescadores.
7 December 1941: Operation "M" -The Attack on the Philippines:
Escorts a convoy and sweeps mines for the Aparri, Philippines invasion force.
12 December 1941:
At 1800 Departs No. 3 anchorage zone off Takao with W-16 and destroyers NAGATSUKI and MINAZUKI escorting a convoy consisting of AKIURA, KAZUURA, ARIZONA, KURAMA, OYAMA and MATSUKAWA MARUs bound for Aparri, Philippines.
17 December 1941:
Departs Takao. Escorts the invasion convoy to Lingayen Gulf.
22 December 1941:
Arrives at Lingayen Gulf. Conducts mine sweeping.
31 December 1941:
Departs Takao escorting a convoy.
3 January 1942:
Arrives at Saipan.
5 January 1942:
Arrives at Davao, Philippines.
7 January 1942: The Invasion of Dutch Borneo:
Rear Admiral Hirose’s Tarakan Occupation Force departs Davao. Hirose's force include MineSweepDiv 11’s W-15, W-13, W-14, W-16, MineSweepDiv 30’s W-17and W-18, SubChasDiv 31’s CH-10, CH-11 and CH-12, patrol boats PB-36, PB-37 and PB-38 and other auxiliary ships.
The Tarakan invasion convoy includes Army transports TSURUGA, LIVERPOOL, HAVANA, KURETAKE, NICHIAI, HITERU, TEIRYU, HANKOW and EHIME MARUs carrying MajGen Sakaguchi Shizuo’s 56th Mixed Infantry Group and the Kure No. 2 Special Naval Landing Force (SNLF) and Navy transports KUNIKAWA, KANO, KAGU, KOKUYO and RAKUTO MARUs. The convoy’s escort is provided by Rear Admiral (later Vice Admiral) Nishimura Shoji’s (39) DesRon 4’s light cruiser NAKA with DesDiv 2’s HARUSAME, SAMIDARE, YUDACHI and MURUSAME, DesDiv 9’s ASAGUMO and MINEGUMO, NATSUGUMO and DesDiv 24’s UMIKAZE, KAWAKAZE, YAMAKAZE and SUZUKAZE. The 21st Air Flotilla’s tenders SANUKI and SANYO MARUs provide air cover.
10 January 1942:
Arrives at Tarakan. Conducts mine sweeping and patrols the peripheral sea area.
11 January 1942:
Rear Admiral Hirose's Force invades Tarakan, Borneo.
21 January 1942: The Invasion of Balikpapan, Borneo.
W-15, W-16, W-17 and W-18 depart Tarakan with the No. 2 Base Force's subchasers CH-10, CH-11 and CH-12 and patrol boats PB-36, PB-37 and PB-38 scorting the Balikpapan Invasion Convoy consisting of 16 transports carrying the Sakaguchi Brigade and the Kure No. 2 SNLF. DesRon 4 provides additional escort. Cover is provided by NAKA with DesDiv 2's YUDACHI, SAMIDARE, HARUSAME, DesDiv 9's ASAGUMO, MURASAME, MINEGUMO, NATSUGUMO and DesDiv 24's KAWAKAZE, YAMAKAZE and UMIKAZE. The 21st Air Flotilla again provides air cover.
Air reconnaissance by the ABDA (American-British-Dutch-Australian) forces is hampered by poor weather, but ABDA Air finally locates the IJN invasion force. The ABDA deploys the submarines USS S-40, USS PORPOISE (SS-172), USS PICKEREL (SS-177), USS STURGEON (SS-187), USS SAURY (SS-189) and the USS SPEARFISH (SS-190) and Dutch submarines KNS K-XIV and KNS K-XVIII to intercept the IJN force.
Timor, Kupang Bay. Rear Admiral (later Vice Admiral) William A. Glassford's Task Force 5's light cruisers USS MARBLEHEAD (CL-12), USS BOISE (CL-47) and Cdr Paul H. Talbot's DesDiv 59's old flush deck, four stack destroyers USS PARROTT (DD-218), USS POPE (DD-225), USS JOHN D. FORD (DD-228) and USS PAUL JONES (DD-230) are ordered by the Admiral (later Senator) Thomas C. Hart, ADBAFLOAT Commander, to intercept the convoy before it reaches Balikpapan. Glassford heads north to find the IJN invasion force but USS BOISE runs aground on an uncharted reef in the Sape Strait. She is forced to retire for repairs. Then USS MARBLEHEAD develops engine trouble and can make no more than 15 knots. DesDiv 59 is detached and increases speed to 27 knots so as to arrive at Balikpapan at midnight on January 23rd.
23 January 1942:
Storms protect the invasion force until it is almost to Balikpapan, Borneo. At 1525, nine Dutch Martin B-10 bombers from Samarinda attack and hit two of the transports, the 7,070-ton TATSUGAMI MARU and 6,557-ton NANA MARU that has to be abandoned and later sinks without casualties. TATSUGAMI MARU continues on to Balikpapan. At 2130, the transports begin disembarking their troops.
24 January 1942:
Dutch Navy LtCdr C. A. J. van Well Groeneveld's (former CO of K-XIV) submarine K-XVIII, operating on the surface due to the weather, fires four bow torpedoes at NAKA, but they all miss. At 0045, Groeneveld attacks and sinks 6,987-ton transport TSURUGA MARU at 00-10N, 118-0E. 38 troops and a single crewman are killed. Nishimura moves his covering force eastwards to carry out antisubmarine sweeps.Talbot's DesDiv 59 arrives from the south. Since Nishimura's covering forces are now to the east searching for submarines, the four destroyers are virtually unopposed.
At about 0245, USS PARROTT fires eight torpedoes at W-15 that she mistakes for a destroyer or cruiser. USS JOHN D. FORD also fires a torpedo at W-15 again. All miss or fail to explode. At 0316, they begin their first attack firing their 4-inch guns and launching ten torpedoes at the anchored transports, but all the torpedoes miss. Cdr Talbot orders another attack. At 0330, USS POPE hits and sinks 3,519-ton transport SUMANOURA MARU. The ship explodes and 9 passengers, and the ship’s whole Navy crew are obliterated. At 0335, USS PARROTT and USS PAUL JONES sink already damaged transport TATSUGAMI MARU with torpedoes. Four crewmen are killed. At 0345, USS JOHN D. FORD sinks the 5,175-ton transport KURETAKE MARU with gunfire and torpedoes. The ship was carrying a total of 1500 infantry of the 56th Mixed Regimental Group (Sakaguchi Brigade) of whom 180 (including some shipping engineers) are killed. Two other transports suffer damage from gunfire and torpedoes but remain afloat. USS POPE and USS PARROTT sink the 2nd Base Force's patrol boat PB-37 with torpedoes and gunfire. At 0350, their torpedoes gone, DesDiv 59 departs southward. At 0300, the Japanese begin landing troops at Balikpapan and, by dawn, they occupy the airfield. That same day, troops invade Kendari, Celebes.

24 February 1942: Operation "J" - The Invasion of Java, Netherlands East Indies:
W-15 escorts a convoy and sweeps mines in support of the Java campaign.

10 March 1942:
Assigned to Vice Admiral (later Admiral) Takasu Shiro's (35) (former CO of ISUZU) 2nd Southern Expeditionary Fleet’s 22nd Special Base Force based at Balikpapan.
24 March 1942:
Borneo. Escorts convoys.
1 July 1942:
Arrives at Singapore. Undergoes repairs.
24 July 1942:
Departs Singapore for Balikpapan.
13 October 1942:
HIE and MANKO MARUs depart Rabaul escorted by W-15.
14 October 1942:
At 2400, minesweeper W-15 joins the escort of the No. 1 Shitai convoy that departed Hong Kong on 26 September consisting of HIE and IJN transport MANKO MARUs escorted by light training cruiser KASHII.
W-15 and MANKO MARU separate. HIE MARU proceeds to Truk.
17 October 1942:
Arrives at Guam Island.
19 October 1942:
Departs Guam.
23 October 1942:
Escorts a convoy from Shortland Islands, Bougainville.

26 October 1942:
Shortland. Refueled with 19 tons oil from oiler OMUROSAN MARU.
31 October 1942:
Departs Shortland for a patrol of the western approaches to Shortland.
1 November 1942:
Arrives at Shortland. Departs later this day escorting a convoy.
3 November 1942:
Arrives at Rabaul.
6 November 1942:
At 1400, W-15, minelayer SHIRATAKA, torpedo boat HIYODORI and subchaser CH-16 depart Rabaul for Shortland escorting an unnumbered convoy consisting of ARIZONA, TOYO, NAGARA, YAMAZUKI, TEIYO, YURI, TOYOKUNI, OIGAWA and SHINANOGAWA MARUs. Although unnumbered this was known as the 2nd Transportation in Force Operation.
8 November 1942:
At 1120, the convoy arrives at Shortland.
10 November 1942:
At 1055 departs Shortland for a patrol of the northern approaches to Shortland. Returns later that day at 1645.
11 November 1942:
At 1740 departs Shortland for a further northern approaches area patrol.
16 November 1942:
At 0735 arrives back at Shortland.
18 November 1942:
At 0945 departs Shortland to patrol the western approaches.
24 November 1942:
At 0520 arrives at Shortland.
26 November 1942:
At 0720 departs Shortland to patrol the western approaches.
27 November 1942:
At 0905 arrives back at Shortland.
28 November 1942:
At 0545 departs Shortland for a northern approaches area patrol.
2 December 1942:
Early am arrives back at Shortland.
3 December 1942:
At 0750 departs Shortland escorting an unidentified warship.
4 December 1942:
At 0500 breaks off escort and patrols western approaches to Shortland. 340 degrees and 18 miles of Mono Island, Treasury Islands, Solomon Islands carries out a depth charge attack. Thereafter patrols the western approaches to Shortland.
5 December 1942:
At 0740 arrives at Shortland. Departs at 1630 escorting an unidentified warship to Rabaul.
9 December 1942:
At 0530 arrives at Rabaul.
12 December 1942:
At 0100 departs Rabaul.
13 December 1942:
At 0530 arrives at Shortland.
14 December 1942:
At 0745 departs Shortland to patrol the western approaches.
19 December 1942:
At 0730 arrives at Shortland.
20 December 1942:
At 1200 departs Shortland to patrol the southern approaches.
21 December 1942:
Around midday steams north to patrol the northern approaches.
22 December 1942:
At 0800 arrives back at Shortland.
23 December 1942:
At 0745 departs Shortland to patrol the northern approaches.
26 December 1942:
At 1815 arrives back at Shortland.
27 December 1942:
At 1045 departs Shortland escorting an unidentified warship.
28 December 1942:
At 2100 arrives at Rabaul.
2 January 1943:
At 0610 departs Rabaul.
3 January 1943:
At 1050 arrives at Buin.
4 January 1943:
At 0800 departs Buin to patrol the southern approaches.
10 January 1943:
At Shortland, supplied with heavy oil. Thereafter patrols the southern approaches.
14 January 1943:
At Shortland, supplied with heavy oil. Thereafter departs escorting a convoy.
15 January 1943:
Arrives at Kolombangara. Departs later the same day escorting a convoy.
16 January 1943:
At 1500 arrives at Shortland. At 1620 departs escorting a convoy.
18 January 1943:
At 2100 arrives at Rabaul.
23 January 1943:
At 1730 departs Rabaul escorting a convoy comsisting of CHINZEI and SHANGHAI MARUs.
25 January 1943:
At 0740 arrives at Buin and departs at 1000 patrol the north entrance to Buin. Thereafter supplied with heavy oil.
26 January 1943:
At 0500 arrives at Buin. Departs later that day on a patrol of the western approaches.
10 February 1943:
Meets up with a convoy and provides an escort north.
16 February 1943:
At 1200 arrives at Truk where the ship remains for the rest of the month.
4 March 1943:
At 0730, W-15 departs Truk for Rabaul escorting an unnumbered convoy consisting of MANKO and KIKUKAWA MARUs.
6 March 1943:
At 0500, the convoy arrives at Rabaul.
9 March 1943:
At 1600, W-15 departs Truk for Rabaul escorting an unnumbered convoy consisting of MIYADONO, UJIGAWA AND TAIKO MARUs.
11 March 1943:
At 0800, the convoy arrives at Shortland. At 1415 W-15 departs for a patrol of the northern approaches.

15 March 1943:
Reassigned to Captain (Rear Admiral posthumously) Itagaki Akira's (47) 1st Base Force, 8th fleet at Buin. The ship arrives back at Shortland later that day.
16 March 1943:
At 1125 departs Shortland to patrol the southern approaches.
21 March 1943:
Completes patrol and begins escorting an unidentified warship.
23 March 1943:
Arrives at Rabaul.
27 March 1943:
At 1130 departs Rabaul escorting SUMIYOSHI MARU and WAKAMATSU MARU No. 1.
28 March 1943:
At 0930 arrives at Shortland.
2 April 1943:
At 0800 arrives at Shortland escorting GISHO MARU and soon after departs to patrol the western approaches.
3 April 1943:
At 1315 switches to patrolling the southern approaches.
4 April 1943:
At 0615 arrives at Shortland.
5 April 1943:
Departs Shortland out to sea.
6 April 1943:
Returns to Shortland to sweep the area.
8 April 1943:
At 0810 departs Shortland out to sea on a sweep, returning at 1315.
9 April 1943:
Departs Shortland out to sea on a sweep, and then undertakes a patrol of the northern approaches.
11 April 1943:
Switches to patrol off the western approaches.
12 April 1943:
Switches back to patrolling off the north of Shortland.
14 April 1943:
Hawaii. Fleet Radio Unit Pacific Fleet (FRUPAC) and two other stations of U.S.N. intelligence, code-named "Magic", intercept and decrypt a Japanese Naval Cipher JN-25D report of a planned inspection tour by Admiral (Fleet Admiral posthumously) Yamamoto Isoroku (32), C-in-C, Combined Fleet, throughout the South Pacific. Yamamoto will fly from Rabaul to Ballale Airfield, near Bougainville. According to the decrypt, on 18 April, Yamamoto and his staff will fly in two Mitsubishi G4M Bettys of the 205th Naval Air Group (NAG), escorted by six Mitsubishi A6M Zeke fighters of the 204th NAG, to depart Rabaul at 0600 and arrive at Ballale at 0800 (JST).
17 April 1943:
At 0800 departs Shortland to sea with W-22 returning at 1130. Later departs on a sweep thereafter returns to Shortland.
18 April 1943:
Easter Sunday. At 0710 (local D/T), 16 P-38 “Lightning” long-range fighter aircraft of the USAAF’s 339th Fighter Squadron under Major (later Colonel) John W. Mitchell take off from Henderson Field, Guadalcanal to ambush Yamamoto in the air as authorized by Admiral (later Fleet Admiral) Chester Nimitz (USNA ’05) and President Roosevelt. At 0610 (JST), Yamamoto’s G4M departs Lakunai airfield at Rabaul, New Britain. Near Kahili, Bougainville, Yamamoto’s plane is shot down by a P-38. In the attack, Yamamoto is hit by machine-gun bullets and KIA. A second GM4 carrying Yamamoto's Chief of Staff, Vice Admiral Ugaki Matome (40) (former CO of HYUGA) is also shot down by a P-38, but Ugaki survives.[1]
That same day, W-15 departs Buin for Ballale to rescue Yamamoto.
20 April 1943:
W-15 embarks the bodies of Admiral Yamamoto and ten other members of his party. The bodies are placed under a tent erected in the fore part of ship. At about 1600, W-15 departs Ballale for Buin. At Buin, an official autopsy of Yamamoto is conducted by LtCdr Tabuchi Jisaburo, Chief Medical Officer, 1st Base Force. Later that day, the remains are cremated by members of the Sasebo SNLF stationed at Buin. Yamamoto’s and the others' ashes are flown to Rabaul, then by flying boat to Truk where they are placed aboard battleship MUSASHI for return to Tokyo.
21 April 1943:
At 0740 escorts a convoy from Buin with W-22 returning at 1145. Later departs Shortland n a sweep.
24 April 1943:
At 0615 W-15 and W-22 puts to sea on a sweep returning later that morning. At 1410 departs for Buka.
25 April 1943:
At 0800 arrives at Buka and meets up with convoy consisting of KOSHU MARU No. 2 and WAKAMATSU MARU No. 1, departing at 1100.
26 April 1943:
At 0900 arrives at Rabaul.
29 April 1943:
At 1715 departs Rabaul escorting KOSHU MARU No. 2.
1 May 1943:
At 0930 arrives at Shortland. At 2300 departs Shortland escorting KASHI MARU and meets up with inbound ship FUKU MARU.
2 May 1943:
Early in the morning both ships arrive back at Shortland.
4 May 1943:
At 0900 departs Shortland to sweep mines, later to meet up with inbound convoy. Undergoes a first escort troop test.
5 May 1943:
At 1430 arrives at Shortland.
6 May 1943:
At 1230 departs Shortland on a sweep, returns there at 1500.
7 May 1943:
At 0925 departs Shortland on a sweep, returns there at 1100. At 2200 escorts FUKU MARU from Shortland.
8 May 1943:
At 0900 arrives back at Shortland.
10 May 1943:
At 1500, W-15 departs Shortland escorting a convoy consisting of KASHI, SHINYU and SANWA MARUs and NISSEN MARU No. 5 and KOSHU MARU No. 2.
12 May 1943:
At 0800, arrives at Rabaul.
17 May 1943:
At 1800, W-15 departs Rabaul for Shortland, Bougainville escorting a convoy consisting of ATSU and HEIWA MARUs and KOSOKU MARU No. 3.
19 May 1943:
At 0920, arrives at Shortland.
20 May 1943:
At 0630 W-15 and W-22 depart Shortland on a sweep, returning at 1100.
22 May 1943:
At 0900 departs Shortland with W-22 escorting an unidentified warship. At 1100 arrives back at Shortland.
23 May 1943:
At 0810 W-15 and W-22 depart Shortland on a sweep, returning at 1030.
27 May 1943:
At 0500 W-15 and W-22 depart to meet up with an unidentified warship. At 1230 both arrive back at Shortland.
28 May 1943:
At 0800 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1130.
29 May 1943:
At 1145 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1500.
30 May 1943:
At 1230 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1410.
31 May 1943:
At 0500 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1100.
1 June 1943:
At 1130 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1400.
2 June 1943:
At 0800 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1145.
4 June 1943:
At 0630 W-15 and W-22 put out to sea on a sweep returning to Shortland at 0730.
5 June 1943:
At 0700 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1015.
6 June 1943:
At 1020 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1415.
7 June 1943:
At 0840 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1115.
8 June 1943:
At 1130 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1400.
10 June 1943:
At 0600 W-15 only puts out to sea escorting seaplane carrier AKITSUSHIMA returning to Shortland at 0800.
12 June 1943:
At 1500 W-15 departs Shortland towing auxiliary patrol boat TENJIN MARU No. 2 escorting a convoy consisting of RYOYU MARU No. 21 and WAKAMATSU MARU No. 1.
13 June 1943:
At 0630 submarine chaser CH-12 joins the escort.
14 June 1943:
At 0610 arrives at Rabaul.
15 ~ 21 June 1943:
Undergoes various repairs and maintenance.
22 June 1943:
At 1300, W-15 departs Rabaul for Shortland escorting a convoy consisting of GIYU, UJIGAWA, KYOSEI, TAKUEI and KARIMO MARUs.
24 June 1943:
At 0830, arrives at Shortland.
25 June 1943:
At 0600 W-15 and W-22 put out to sea on a sweep returning to Shortland at 0715.
26 June 1943:
At 0700 W-15 departs Shortland on patrol.
27 June 1943:
At 1100 arrives back at Shortland.
28 June 1943:
At 0630 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1030.
30 June 1943:
At 0630 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1130.
4 July 1943:
At 0600 departs on a escort operation returning at 1530 that same day.
7 July 1943:
At 0600 departs on a escort operation returning at 1500 that same day.
11 July 1943:
At 0730 W-15 and W-22 put out to sea on a sweep returning to Shortland at 0845.
12 July 1943:
At 0630 W-15 and W-22 put out to sea on a sweep returning to Shortland at 1310.
18 July 1943:
Buin, Bougainville, Solomons. USN VB-11 and USMC VMSB-132 "Dauntless" SBD dive-bombers and USN VT-11 and VT-21 "Avenger" TBF torpedo-bombers escorted by USMC VMF 122, VMF 211 and VMF 221 F4U "Corsair" fighters and USAAF B-24 "Liberator" heavy bombers escorted by USAAF P-39 "Airacobra" and P-40 "Warhawk" fighters and RNZAF P-40s attack shipping in the Buin-Kahili area. They sink destroyer HATSUYUKI taking down 82 of her crew and 38 passengers and damage destroyers HATSUKAZE and YUNAGI and W-15 in the attack. Later, W-22 tows W-15 to Rabaul.
20 July 1943:
At 0930 W-15 and W-22 arrive at Rabaul.
7 August 1943:
Departs Rabaul accompaning the fleet.
9 August 1943:
Arrives at Kavieng.
10 August 1943:
Auxiliary sub-chaser SHONAN MARU No. 15 depart Rabaul escorting convoy No. 2072 consisting of two unknown vessels (possibly SHOEI MARU (1986 gt) was one). The convoy is bound for Truk. At Kavieng W-15 joins convoy.
13 August 1943:
Arrives at Truk.
15 August 1943:
Departs Truk escorting a convoy consisting of Navy storeships KOSOKU MARU No. 3 and KITAKAMI MARU and tanker HISHI MARU No. 2.
19 August 1943:
Arrives at Saipan.
21 August 1943:
Departs Saipan still escorting the same convoy bound for Kure and Sasebo.
28 August 1943:
Arrives at Kure.
1 September 1943:
Undergoes repairs for eight days.
1 October 1943:
Lt Niwa Eitaro assumes command from Lt (later LtCdr) Sato Choshiro. Shown as in Kure for entire month.
15 November 1943:
Departs Kure and late that day arrives at Saiki.
22 November 1943:
Departs Saiki and soon after arrives at Otaka.
24 November 1943:
Departs Otaka for Kure area.
25 November 1943:
Assigned to the Sasebo Guard Unit.
3 December 1943:
Departs Sasebo for a night exercise.
4 December 1943:
At 1023 loads fresh food and at 1155 departs Sasebo and at 1650 arrives at Fukue.
6 December 1943:
At 0450 departs Fukue for a combat exercise. At 1250 arrives at Mikuriya, Imari Wan.
7 December 1943:
At 0700 W-15 departs Imari Wan for Shanghai escorting convoy SHI-704 consisting of RYOKA, NIKKIN and HOKUJU MARUs and DAIUN MARU No. 2. At 1400, the convoy runs into heavy weather. DAIUN MARU No. 2 returns to port.
8 December 1943:
At 0135, because of poor visability W-15 loses sight of NIKKIN and HOKUJU MARUs and at 0200 also loses sight of RYOKA MARU. Finally at 0700, W15 orders the convoy to return to port. They all arrive back at Mikuriya later this day.
9 December 1943:
At 1655, in better weather, W-15, RYOKA and NIKKIN MARUs depart Imari Wan. At 2007, carries out an anti submarine sweep.
12 December 1943:
At 0300 the escort ends and W-15 detaches. At 1230, the convoy arrives at Shanghai. At 1245, W-15 is supplied with heavy oil, coal and is replenished with fresh water.
14 December 1943:
At 0830 departs Shanghai. At 1015, because of heavy fog temporarily anchors at Wusong. At 1810, departs Wusong. At 2310 meets up off Yushan lighthouse with TOFUKU MARU, the sole member of convoy MO-401.
15 December 1943:
At 0235, departs escorting TOFUKU MARU.
18 December 1943:
At 1030, escort ends and detaches and at 1630 arrives at Sasebo. She is supplied with coal and replenished with fresh water.
20 December 1943:
At 1000 Departs Sasebo and arrives at Kaminoura, Goto Retto later this day. Later departs Kaminoura for an anti submarine sweep. W-15 has to find and sink an enemy submarine discovered by the ORYOKU MARU in convoy No. 227.
21 December 1943:
At 0922, (N32.07-E129.33 an enemy submarine is detected. At 0926, drops 10 depth charges and at 0954, drops another eight depth charges. The shock of a prematurely exploded depth charge causes an heavy oil tank rupture. At 1042, (N31.08-E129.37) an enemy submarine periscope is detected. At 1044, drops 10 depth charges. At 1120, drops 10 depth charges. Finally at 1217, drops 6 depth charges. At 1245, emergency repairs of the heavy oil tank are completed. Escorts convoy No. 227 which has been diverted to Tachibana Bay at Asozaki Seto. At 1300, the convoy arrives at Tachibana Bay. At 1310, hands over the escort task to auxiliary subchaser NAGATO MARU. At 1710, temprarily anchors in Tachibana Bay. At 1810, continues with the anti-submarine sweep.
22 December 1943:
At 0190 ends the anti submarine sweep and returns to Sasebo where she arrives at 1240. At 1413, is resupplied and at 1730, loads depth charges.
23 December 1943:
At 0940 docked in No. 3 dock and at 1633 undocked at Sasebo.
24 December 1943:
At 1730, W-15 departs Sasebo and arrives at Mikuriya, Imari Wan later that day. At 1730, W-15 departs Mikuriya for Shanghai escorting convoy SHI-405 consisting of KOKKA, YUZAN, MIIKESAN, SHOKEI, and HOKUJU MARUs and BANSHU MARU No. 32.
28 December 1943:
At 0400, ends escort. At 1315, the convoy arrives at Shanghai.
29 December 1943:
Resupplied.
30 December 1943:
At 1520, W-15 departs Shanghai escorting convoy MO-006 consisting of NARUO, WAZAN, HIKACHI, MISHIMA, KORYU and JUKO MARUs.
3 January 1944:
At 0200, escort ends. At 0855, arrives at Sasebo. Loads coal.
5 January 1944:
Projected to meet up with convoy MO-501 that had departed Shanghai and is en route for northern Kyushu. Returns to Sasebo.
7 January 1944:
Supplied with heavy oil and replenished with fresh water.
10 January 1944:
At 1330 departs Sasebo and at 1800 arrives at Mikuriya, Imari Wan.
15 January 1944:
At 0900 departs Imari Wan and at 1600 arrives at Nagasaki. Loads 1700 gold bars weighing 6 tons
16 January 1944:
Loads coal and is replenished with fresh water.
17 January 1944:
At 1130 departs Nagasaki escorting convoy SHI-701 consisting only of passenger ship UNZEN MARU.
19 January 1944:
At 1645, escort endsAt 2140 arrives at Woosung.
20 January 1944:
At 0900 arrives at Shanghai. At 1000 loads heavy oil and coal and is replenished with fresh water.
22 January 1944:
At 0730 departs Shanghai escorting convoy MO-201 consisting of UNZEN MARU and escorts ship to northern Kyushu.
24 January 1944:
At 1345 the convoy is dissolved and at 1650 W-15 arrives at Sasebo and loads heavy oil and is replenished with fresh water.
25 January 1944:
Loads coal.
28 January 1944:
At 0730 W-15 departs Sasebo escorting convoy SHI-801 consisting of passenger ship UNZEN MARU bound for Shanghai.
30 January 1944:
At 0830, the convoy is dissolved and at 1530 arrives at Shanghai.
31 January 1944:
Loads heavy oil and coal and is replenished with fresh water.
1 February 1944:
At 1150, W-15 departs Shanghai escorting convoy MO-106 consisting of NARUO (ex Panamanian ESTERO), MALAY, UGA, MUNAKATA, AOKI (ex Italian AMBA ALAGI) and WAKAMATSU MARUs. Shortly after leaving, high winds cause the convoy to lose formation.
3 February 1944:
At 1715, arrives off the south east coast off Chindo (Jindo), Chosen (now South Korea) and waits there for the convoy. At 1715, the ships began reassembling near Mokpo.
4 February 1944:
At 0140, NARUO and UGA MARUs depart. At 1040, joins with the No. 1 and No. 2 ships (NARUO and UGA MARUs) of the convoy and starts escorting. The others follow later that day.
5 February 1944:
At 0210 the convoy is dissolved and at 1005, arrives at Sasebo. At 1230, loads heavy oil and coal and is replenished with fresh water.
8 February 1944:
At 0720, W-15 departs Sasebo escorting convoy SHI-802 consisting of UNZEN and KITSURIN MARUs.
10 February 1944:
At 1220, the convoy is dissolved and at 1750, arrives at Shanghai.
12 February 1944:
Loads heavy oil and oil and is replenished with fresh water.
13 February 1944:
At 1250, W-15 departs Shanghai escorting convoy MONA-302 consisting of UNZEN and KITSURIN MARUs. At 1855, remains at the Yangtze River mouth during the night.
16 February 1944:
At 0810, drops 2 depth charges and the convoy is dissolved and at 1305, W-15 arrives at Sasebo. At 1640, loads heavy oil and coal and is replenished with water. Probably undergoes repairs and upkeep.
25 February 1944:
At 0825 departs Sasebo. At 1600 anchors at Tomie, Goto Retto.
26 February 1944:
At 0955 departs Tomie.
27 February 1944:
At 1552, detects an enemy submarine. Drops 17 depth charges.
2 March 1944:
At 1100 arrives at Kirun.
3 March 1944:
At 1900 departs Kirun.
5 March 1944:
In position 25-52N 122-43E providing escort for weather ship KAIYO No. 6. At 1857 both arrive at Kirun.
7 March 1944:
At 1700 departs Kirun.
9 March 1944:
At 1250 arrives at Kirun.
10 March 1944:
At 1700 departs Kirun.
12 March 1944:
At 1105 arrives at Kirun.
14 March 1944:
At 1700 departs Kirun.
18 March 1944:
At 0930 arrives at Sasebo.
22 March 1944:
At 1630 departs Sasebo.
25 March 1944:
At 1730 arrives at Sasebo.
5 April 1944:
At 0500 departs Sasebo with submarine chaser KAII to escort minelayer TOKIWA as well as SAIGON, SHINKO and KOEI MARUs. At 1515 off Yoshimi the escort duties cease and W-15 anchors.
6 April 1944:
Transfers to nearby Mutsure to avoid stormy weather.
10 April 1944:
Assigned to the Sasebo Naval District's 4th Surface Escort Division. Departs Yoshimi for a drowning rescue exercise. At 1515, arrives back at Yoshimi and anchors at the 1st anchorage. At 2130, transfers to the 18th Squadron anchorage.
11 April 1944:
At 0500 departs Yoshimi. En route executes an anti-aircraft battle excercise. At 1640 arrives at Sasebo.
12 April 1944:
Loads heavy oil and coal and is replenished with fresh water.
17 April 1944:
At 0900 departs Sasebo escorting 18th Sentai consisting of minelayer TOKIWA, to Kirun with torpedo boat TOMOZURU, submarine chasers CH-58, and KAII and minelayer TAKASHIMA. From 1200 till 1400 various training drills are carried out. At 1555 anchors in the Terajima Straits.
18 April 1944:
At 1700 transfers to nearby Ebisu Wan to avoid stormy weather.
19 April 1944:
At 0940, loads coal and is replenished with fresh water. At 1700 departs Ebisu Wan and at 2105 anchors again in Terajima Straits.
20 April 1944:
At 1625 departs Terajima Straits escorting the 18th Sentai (Squadron) consisting of minelayer TOKIWA.
23 April 1944:
From 0835 till 1630 mines are being laid after which the second minefield is completed. At 1645, TOKIWA sights a periscope. At 2205, drops 3 depth charges.
24 April 1944:
At 1245 arrives at Kirun.
25 April 1944:
Loads heavy oil and coal and is replenished with fresh water.
26 April 1944:
At 0800 departs Kirun still escorting the 18th Sentai.
27 April 1944:
At 1200, at N27.30-E124.50, detaches for an anti submarine sweep.
28 April 1944:
At 2350, ends the anti submarine sweep and heads towards Sasebo.
29 April 1944:
At 1010, changes course and heads towards Seso. At 1427, at N28.30-E128.55, undergoes a torpedo attack with three torpedoes but they miss. Immediately after this drops three depth charges.
30 April 1944:
At 0200, ends the anti submarine sweep and heads towards Seso. At 0620 arrives at Seso. Loads heavy oil and coal and is replenished with fresh water. At 1200 departs Seso on an anti submarine sweep. At 1400 starts the anti submarine sweep.
1 May 1944:
At 1030, ends the anti submaine sweep, returns to Seso and arrives there later this day.
2 May 1944:
Departs Seso escorting NICHIRIN MARU (ex British MATA HARI). At 0630, they return to Seso because of heavy fog. At 0730, they arrive back at Seso. At 1050, they depart again
3 May 1944:
At 1520 they arrive at Sasebo.
4 May 1944:
Loads heavy oil and coal and is replenished with fresh water.
5 May 1944:
At 1430, supplied with depth charges.
6 May 1944:
At 1225 departs Sasebo.
7 May 1944:
At 1352 meets up with MAMIYA that has been damaged by USS SPEARFISH in 33-18N 127-11E while part of convoy TAMO-18. At 1530 submarine chaser KAII commences towing MAMIYA and kaibokan FUKUE, CD-2, minelayer TAKASHIMA, submarine chaser CH-58 and auxiliary submarine chaser CHOUN MARU No. 16 all escort ship.
8 May 1944:
At 1000, ends the escort and at 1225, arrives at Sasebo. At 1630, loads heavy oil and coal and is replenished with fresh water.
10 May 1944:
Moores alongside a quay. A type 93 sonar is replaced and installed.

11 May 1944:
Adjusting the type 93 sonar.
12 May 1944:
At 0820 transfers to Ebisu Wan for a trial of the type 93 sonar. At 1030, the trial is completed and at 1140 returns to Sasebo. At 1710 departs Sasebo.
13 May 1944:
At 1110 arrives at Kagoshima Wan (Bay). Embarks two flight attendant staff members. At 1850 departs Kagoshima with minelayer TSUBAME, auxiliary minesweeper HOEI MARU and auxiliary submarine chaser NAGATO MARU escorting convoy ROKU-307 consisting of TAIKAI MARU and six unidentified merchant ships.
14 May 1944:
At 1940 arrives at Seso. TAIKAI MARU is detached off Koniya.
15 May 1944:
At 0225 departs Seso and at 1915 arrives at Sesoko.
16 May 1944:
At 0350 departs Sesoko and at 0850 arrives at Naha. At 1000, loads coal and is replenished with fresh water. At 2345 W-15 departs Naha for Keelung with minelayers NIIZAKI and TSUBAME, auxiliary minesweeper HAKATA MARU No. 7 and BANSHU MARU No. 51 escorting convoy NATA-613 (or NATA-611) consisting of BAIEI, KOSHIN MARUs, NANSHIN MARU No. 14, NANSHIN MARU No. 27, HORAI MARU No. 2 and six unidentified merchant ships.
18 May 1944:
At 0835 arrives at Ishigaki Jima and at 2050 departs.
19 May 1944:
At 1400, ends the escort and detaches. At 1545 arrives at Kirun.
20 May 1944:
At 0740, loads heavy oil and coal and is replenished with fresh water.
21 May 1944:
At 0730 departs Kirun.
22 May 1944:
At 1750 arrives at Naha.
23 May 1944:
At 0850, loads coal and is replenished with fresh water. At 1450 W-15 departs Naha for Kagoshima via Koniya with minelayers NIIZAKI (part way only) and TSUBAME, auxiliary minesweeper HAKATA MARU No. 6, and auxiliary YUKO MARU escorting convoy NAKA-305 consisting of five unidentified merchant ships. At 1850 the convoy anchors off Sesoko.
24 May 1944:
At 0150 departs Sesoko and at 2000 the escorts arrive at Seso.
25 May 1944:
At 0025 departs Seso.
26 May 1944:
At 0230, ends the escort and detaches. At 0645 arrives at Yamakawa. At 0800, loads coal and is replenished with fresh water; departs there at 1200 and arrives at Kagoshima at 1505.
29 May 1944:
At 1230 W-15 departs Kagoshima for Keelung with minelayers NIIZAKI and TSUBAME, auxiliary minesweeper HAKATA MARU No. 6, auxiliary patrol boat RYUSEI MARU escorting convoy KATA-906 consisting of TERUKUNI, SHOTO, TOYAMA, KAIJO, MIYAKO and AMOY MARUs and one unidentified merchant ship.
30 May 1944:
Arrives at Koniya. At 1630 the escorts anchor at Seso.
1 June 1944:
At 0200, departs Seso. At 1830, ends the escort and detaches. Arrives at Naha later this day.
2 June 1944:
At 0830, loads coal and is replenished with fresh water. At 1450 W-15 departs Naha for Kagoshima with minelayer TSUBAME, auxiliary patrol boats HOKOKU MARU No. 3 GO, CHIKUTO and RYUSEI MARUs escorting convoy NAKA-204 consisting of YOSHU, NICHIRIN (ex British MATA HARI), AMAKUSA, NISSHIN (NITTSU) MARUs, and NANKAI MARU No.1. At 1815 arrives at Sesoko.
3 June 1944:
At 0250 departs Sesoko. Later that evening arrives at Koniya with the escorts arriving at nearby Seso at 1820.
4 June 1944:
At 0200, Departs Seso. The convoy departs Koniya.
5 June 1944:
At 0530, ends the escort and detaches. At 0840, arrives at Kagoshima. Loads coal and is replenished with fresh water.
6 June 1944:
At 1250 W-15 departs Kagoshima with minelayer TSUBAME, auxilary minesweepers HAKATA MARU No. 6, BANSHU MARU No. 51, TOSHI MARU No. 7, SHIMPO MARU and auxiliary patrol boat CHOUN MARU No. 13 escorting convoy KATA-614 consisting of IWATO, SAKISHIMA, TOYOSAKA, SANYO (976 gt), DAISHIN MARUs, SHINTAI MARU No.2, UNYO MARU No.7, YAEI MARU No.5, NANSHIN MARU No.18, TOSHU MARU towing a Hyoteki and five unidentifed merchant ships.
7 June 1944:
Arrives at Koniya. At 1640 W-15 arrives at nearby Seso.
8 June 1944:
Departs Koniya. The convoy divides in half some ships proceeding to Ishigaki Jima (arrived 11 June, departs 12 June).
9 June 1944:
At 0100 departs Seso. At 1950 arrives at Naha.
10 June 1944:
At 0750, loads heavy oil and coal and is replenished with fresh water.
11 June 1944:
At 0054 departs Naha.
12 June 1944:
At 0710, arrives at Ishigaki and departs at 2145.
13 June 1944:
At 1100, supported by an aircraft drops 6 depth charges at 25-00 N-122-20 E. It turns out that the target is misidentified by the aircraft. At 1510 arrives at Kirun.
14 June 1944:
At 0730, loads heavy oil and coal and is replenished with fresh water.
15 June 1944:
At 1210 departs Kirun. At 1510, starts escorting a convoy.
16 June 1944:
At 0900, escort ends and detaches. At 1350 arrives at Takao. At 1600, loads heavy oil and coal, is replensihed with fresh water and provisioned with fresh food.
17 June 1944:
At 1100 departs Takao for Manila.
20 June 1944:
At 0945 arrives at Manila. At 1300, loads heavy oil and coal and is replenished with fresh water. At 1515 departs Manila.
22 June 1944:
At 0740 arrives at Cebu.At 0835, loads heavy oil and coal and is replenished with fresh water.
23 June 1944:
At 0800 departs Cebu escorting tanker YUHO MARU. At 2150 arrives at Guimaras.
24 June 1944:
Departs Guimaras escorting damaged auxiliary oiler ITSUKUSHIMA MARU for Manila. At 1600, they return to Guimaras where they arrive later this day.
28 June 1944:
At 1550, alongside ITSUKUSHIMA MARU and supplied with oil.
1 July 1944:
At 0250 departs Guimaras escorting damaged tanker ITSUKUSHIMA MARU. At 2318, ITSUKUSHIMA MARU detects an enemy submarine at 13-28N, 121-59E. Six depth charges are dropped and 40 MG rounds expended. W-15 also attacked it with depth charges but the target turns out to be misidentified.
2 July 1944:
At 1207 arrives at Manila. At 1600, loads heavy oil and is replenished with fresh water.
3 July 1944:
At 1100, loads coal.
14 July 1944:
At 0850 W-15 and minelayer KYOSAI depart Manila escorting convoy MATA-24A consisting only of KAGU MARU.
16 July 1944:
At 1400, ends the escort. At 1425, arrives at Takao. At 1600, loads heavy oil and is replenished with fresh water.
17 July 1944:
At 0815 loads coal. At 1205 departs Takao and at 1816 arrives at Mako.
18 July 1944:
At 0555 departs Mako.
19 July 1944:
At 0530, starts escorting convoy KATA-910. At 1835, ends escort and detaches. At 1910 arrives at Kirun.
20 July 1944:
At 0730, loads heavy oil and is replenished with fresh water.
24 July 1944:
At 1755, anchors outside Kirun harbor.
25 July 1944:
At 0300 W-15 departs Kirun with minelayer NUWAJIMA, auxiliary minesweeper SHINPO MARU, auxiliary patrol boats NAGATO, RYUSEI and TAIAN MARUs and auxiliary YUKO MARU escorting convoy TAKA-205 consisting of EDOGAWA, TAISHO, TORAI MARUs and nine unidentified merchant ships. At 2355 anchors off Ishigaki Jima.
26 July 1944:
At 0855 departs Ishigaki Jima.
27 July 1944:
At 1455 arrives at Naha. UNTEN MARU joins the convoy.
28 July 1944:
At 0700, loads heavy oil and coal and is replenished with fresh water. At 1157 departs Naha.
29 July 1944:
At 1630 arrives at Yamakawa. Loads heavy oil and is replenished with fresh water.
30 July 1944:
Anchors because of stormy weather.
31 July 1944:
At 1153 departs Yamakawa and at 1430 arrives at Kagoshima.
4 August 1944:
Departs Kagoshima escorting convoy KATA-416. At 1010, due to a typhoon, they return to Kagoshima where they arrive later this day.
5 August 1944:
At 0500, Departs Kagoshima to avoid the typhoon. At 0515, damaged after the port bow of the army auxiliary transport FUSHIMI MARU collides with the centre starboard side of W-15. At 1000, starts repairs. At 1800, transfers to Sakura-jima to shelter from the typhoon.
6 August 1944:
At 1755 departs Kagoshima.
7 August 1944:
At 1105 arrives at Sasebo.
8 August 1944:
Starts repairs of typhoon damage and replacement of equipment.
9 August 1944:
Depth charges and ammunition are off loaded.
13 August 1944:
Enters No.5 Dock at Sasebo for repairs.
25 August 1944:
At 1900, depth charges and ammunition are loaded.
26 August 1944:
At 0830 undocked.
27 August 1944:
Departs Sasebo for trials and returns later this day.
30 August 1944:
At 1725 departs Sasebo and at 1908 arrives at nearby Ebisu Wan.
31 August 1944:
At 0740 departs Ebisu Wan escorting supply ship MUROTO and at 1653 arrives at Ushibuka.
1 September 1944:
At 0516 departs Ushibuka escorting storeship MUROTO. At 1717 arrives at Kagoshima.
2 September 1944:
At 0830, loads coal and other supplies.
6 September 1944:
Departs Kagoshima. At 1850, arrives at Chiringashima.
7 September 1944:
At 0505 W-15 departs Chiringashima, near Kagoshima with kaibokan CD-30, minelayers NUWAJIMA, NIIZAKI and auxiliary minesweepers TAKUNAN MARU No. 3, CHITOSE MARU and auxiliary CHOUN MARU No. 13 escorting convoy KATA-719 consisting of CHOSAN, EKISAN, AITOKU, SAKISHIMA, DAITOKU, TAIHOKU and NAKAGAWA, MUSASHI, MIFUKU, YOKO MARUs, NISSHO MARU No.1, NANSHIN MARU No.26, and thirteen other unidentified merchant ships. Convoy KANA-602 consisting of NICHIRIN MARU (ex British MATA HARI)and one unidentified merchant ship appears to join convoy as far as Naha and specific escort is provided by auxiliary minesweepers KAIYO MARU No. 1 GO and auxiliary patrol boat HOKOKU MARU No. 3 GO.
Most of the transports carry troops including replacements for 298th, 299th, 300th, and 301st Independent Infantry Battalions of the 45th Independent Mixed Brigade on Okinawa; Headquarters and 1st Company, 1st Independent Mortar Regiment; 118th Independent Maintenance Unit and 145th Independent Maintenance Unit; brigade headquarters and elements of 393rd, 394th and 396th Independent Infantry Battalions of the 59th Independent Mixed Brigade, and 398th, 399th, 400th Independent Infantry Battalions, field artillery and signal troops of the 60th Independent Mixed Brigade on DAITOKU MARU; elements of 393rd, 394th and 396th Independent Infantry Battalions of the 59th Independent Mixed Brigade and 398th, 399th, 400th Independent Infantry Battalions of the 50th Independent Mixed Brigade on DAIHAKU MARU; and elements, 4th Company, 1st Independent Mortar Regiment; and probably small elements of the 59th and 60th Independent Mixed Brigades on NAKAGAWA MARU.
9 September 1944:
At 1000, arrives at Naha. Part of the convoy is detached. At 1230, loads coal and other supplies.
11 September 1944:
At 1245 departs Naha and at 1325 arrives at Kerama Retto.
12 September 1944:
At 1250 departs Kerama Retto and at 1530 arrives back at Naha. At 2345 departs Naha escorting KATA-719 first contingent.
13 September 1944:
At 1919, detaches to escort an unidentified ship with engine failure. At 2202, the unidentified ships engine failure is resolved. At 2314, arrives at Miyakoshima.
14 September 1944:
At 0921, departs Miyakoshima escorting convoy KATA-719. At 2113 arrives at Ishigaki Shima and departs at 2235.
15 September 1944:
At 1945, convoy KATA-719 dissolves. At 2130 arrives at Kirun, Formosa.
16 September 1944:
In the afternoon loads coal and other supplies.
18 September 1944:
At 1800, anchors.
19 September 1944:
At 0110 W-15 departs Keelung for Kagoshima with kaibokan CD-30, auxiliary minesweepers TAKUNAN MARU No. 3, TOSHI MARU No. 7 and TAIHEI MARU No. 3 GO, auxiliary patrol boat TAIAN MARU escorting convoy TAKA-909 consisting of DAIHAKU, KEIUN MARUs, TOSEI MARU No. 2 and seven unidentified merchant ships enroute to Kagoshima, some direct and some via Naha. At 0820, at 24-52N 122-23E TOSEI MARU No.2 is torpedoed. At 0830, leads the fleeing convoy to Kirun. At 1256, off Kirun Island detaches and heads towards the location where the submarine attack took place. At 1625, arrives at the location and together with kaibokan CD-30 starts attacking the enemy submarine. At 1700, stops the anti submarine sweep and heads towards Kirun. At 2000, arrives at Kirun.
20 September 1944:
At 0626, departs Kirun.
21 September 1944:
At 1530 arrives at Miyako and departs at 2200.
23 September 1944:
At 1350, the convoy is dissolved. At 1530 arrives at Naha. Loads heavy oil and coal and is replenished with fresh water.
24 September 1944:
At 0620 departs Naha and at 0927 arrives at Sesoko.
25 September 1944:
At 0520 departs Sesoko.
27 September 1944:
At 0700, the convoy is dissolved. At 0822 arrives at Kagoshima.
6 October 1944:
W-15 departs Keelung for Kagoshima with torpedo boat MANAZURU, minelayer NUWAJIMA, auxiliary netlayer SHINTO MARU No. 2, kaibokan CD-30, subchaser CH-49, auxiliary minesweepers CHOUN MARU No. 13, KAIYO MARU No. 1 GO, auxiliary patrol boats CHOUN MARU No. 13, SOBUN and HOKOKU MARUs escorting convoy TAKA-410 consisting of DAIYA, TAIKAI, TAKUSAN MARUs and eleven unidentified merchant ships enroute to Kagoshima, some direct and some via Miyako Shima and Kasari Bay.
9 October 1944:
Lt Morisawa Ikuo assumes command.
21 October 1944:
At 1200, W-15 departs Kagoshima with torpedo boat MANAZURU, kaibokan CD-30, subchaser CH-49, storeship KINEZAKI, auxiliary minesweepers SHONAN MARU No. 16, TOSHI MARU No. 7 and HIMESHIMA MARU escorting convoy KATA-916 consisting of MUROTO, CHOJUSAN, TOMITSU, EDOGAWA, BANSEI, TENSHO, AMAKUSA, SHINTON, SANKA, SANJIN, HAKKA, HAYAMA, TORAI, TAIKYU, SAKISHIMA, RYUKYU, KANKYO and AMOY MARUs.
22 October 1944:
At 0730, LtCdr (later Vice Admiral) Vernon L. Lowrance's (USNA ’30) USS SEA DOG (SS-401) torpedoes and sinks storeship MUROTO and damages TOMITSU MARU at 29-18N, 129-44. TORAI MARU takes TOMITSU Maru in tow. The convoy then shelters in Kasari Bay, Amami Oshima. The rest of the day the escorts attack the USS SEA DOG. At 1600, W-15 ends the anti submarine sweep and escorts CD-30 and TORAI MARU first to Kasari Wan and then to Naha.
25 October 1944:
At 1230, arrives at Naha.
27 October 1944:
W-15 departs Naha for Koniya with torpedo boat MANAZURU and auxiliary minesweeper TOSHI MARU No. 7 escorting the “Hakko Maru” convoy consisting of HAKKO MARU.
3 November 1944:
W-15 and W-16 depart Kagoshima with torpedo boat MANAZURU, auxiliary gunboat CHOJUSAN MARU, auxiliary minesweeper SEKI MARU and SHONAN MARU No. 16 escorting convoy KATA-322 consisting of KAIRYU, KINZAN, KEIUN, KENJO, SEIZAN, DAISEI, SOSHU, GINZAN, KEIZAN, KEIJO, NICHIRIN (ex British MATA HARI), DAISHIN, HIKOSAN and MALAY MARUs, HOEI MARU No. 5 and TAMON MARU No.12.
6 November 1944:
Arrives at Naha. Part of the convoy detaches and remains there.
7 November 1944:
W-15 departs Naha for Kagoshima with torpedo boat MANAZURU, auxiliary gunboat CHOJUSAN MARU, subchaser CH-49, auxiliary patrol boat TAIAN MARU, auxiliary minesweepers SHONAN MARU No. 16, TOSHI MARU No. 7, CHOUN MARU No. 8, CHITOSE and SEKI MARUs escorting convoy NAKA-713 consisting of DAISHIN (1306 gt), EDOGAWA (1972 gt) MARUs, and eleven unidentified merchant ships.
9 November 1944:
CHOJUSAN MARU is torpedoed and sunk at 31-15N, 129-10E by Cdr (later Rear Admiral) Charles E. Loughlin's (USNA '33) USS QUEENFISH (SS-393). One crewman is KIA.
10 November 1944:
Arrives at Kagoshima.
20 November 1944:
At 1500, arrives at Keelung.
22 November 1944:
Departs Kirun escorting convoy TAKA-206. At 2240, N24.22-E122.31, torpedoboat MANAZURU sights a surfaced enemy submarine at. At 2339, the second ship in the column, HOZAN MARU, is torpedoed as well as AMAKUSA MARU and SAKAE MARU. All three ships are sunk. At 2346, carries out the first anti sbmarine attack and drops 12 depth charges.
23 November 1944:
At 0005, carries out a second anti submarine attack and drops 2 depth charges. At 0030, discovers survivors. At 0035 starts rescuing them. By 0215 has rescued 52 people. At 0730, escorts auxiliary minesweeper SEKI MARU which is retiring to Funao. En route sights MITO MARU. Detaches from SEKI MARU to search for other convoy ships.
26 November 1944:
W-15 departs Keelung for Kagoshima with kaibokan CD-30 and CD-42, subchaser CH-49, auxiliary minesweepers TAIHEI MARU No. 3 GO, SEKI MARU and SHONAN MARU No. 16 and auxiliary patrol boat TAIAN MARU escorting convoy TAKA-608 consisting of SAKISHIMA MARU and twelve unidentified merchant ships en route to Kagoshima, some direct and some via Naha.
27 November 1944:
At 2000, arrives at Naha.
11 December 1944:
W-15 departs Keelung escorting convoy TAKA-107 consisting of NANKING, TENSHO MARUs and fourteen unidentified merchant ships escorted by kaibokan CD-44, torpedo boat MANAZURU, minelayer NUWAJIMA and auxiliary minesweepers TAKUNAN MARU No. 3 and TOSHI MARU No. 7 enroute to Kagoshima, some direct and some via Miyako Shima and Kasari Bay.
25 December 1944:
W-15 departs Kagoshima enroute to Keelung, via Naha and Miyako Shima with torpedo boat MANAZURU (part way), kaibokan CD-30 (part way), CD-42 (part way), CD-44, auxiliary minesweepers BANSHU MARU No. 51, TAKUNAN MARU No. 3, TOSHI MARU No. 7 and CHOUN MARU No. 8 escorting convoy KATA-506 consisting of KISHUN MARU and eight unidentified merchant ships. W-15 only escorts the convoy part way.
1 January 1945:
At Kirun.
3 January 1945:
Undergoes an air attack.
7 January 1945:
At 1801 departs Kirun and at 1829 remains off Kirun.
8 January 1945:
At 0145, departs off Kirun with kaibokan CD-30 and CD-68, and auxiliary minesweepers TAKUNAN MARU No. 3 and BANSHU MARU No. 51 escorting convoy TAKA-508.
10 January 1945:
At 1500, the convoy dissolves and starts an anti submarine sweep.
11 January 1945:
At 1350 ends the anti submarine sweep and heads towards Naha. At 1738 arrives at Naha.
12 January 1945:
Loads heavy oil and coal ans is replenished with fresh water.
14 January 1945:
At 1154 departs Naha. At 1517 arrives at Sesoko.
15 January 1945:
At 2233 departs Sesoko.
16 January 1945:
At 2159 arrives at Seso.
17 January 1945:
Loads heavy oil.
18 January 1945:
At 2042 departs Seso.
20 January 1945:
At 0230 arrives at Kagoshima.
24 January 1945:
At 1149 W-15, kaibokan CD-44, CD-68, torpedo boat MANAZURU, minelayer NUWAJIMA, auxiliary minesweepers TAKUNAN MARU No. 3, CHOUN MARU No. 8 and HIMESHIMA and SEKI MARUs depart Kagoshima escorting convoy KATA-407 consisting of tanker KINYU MARU No. 7 and probably other ships.
25 January 1945:
At 0625, a surfaced enemy submarine is sighted. From 0645 til 0910 attacked the submarine. At 0910 handed over the anti submarine sweep task to kaibokan CD-68 and rejoined the convoy.
26 January 1945:
Arrives at Seso. Loads heavy oil and is replenished with fresh water. Departs later this day still escorting convoy KATA-407.
27 January 1945:
At 1630 the convoy disssolves. At 1858 arrives at Naha.
28 January 1945:
Loads coal and provisioned with fresh food.
30 January 1945:
At 0722 departs Naha still escorting KATA-407 for Kirun. NUWAJIMA has been detached.
1 February 1945:
At 0900, the convoy dissolves. At 1006 arrives at Kirun.
2 February 1945:
Loads coal.
5 February 1945:
At 1730 departs Kirun but returns at 1827.
6 February 1945:
At 0200 departs Kirun with auxiliary minesweeper BANSHU MARU No. 51 and likely others escorting convoy TAKA-604 (Stage 1) consisting of TAISHO, KINYU, DORYO and SANKA MARUs.
7 February 1945:
At 0920, devirted to Miyako because of stormy weather. At 1605 anchors off Miyako.
8 February 1945:
At 1316 departs Miyako.
9 February 1945:
At 1619 arrives at Naha.
10 February 1945:
Loads heavy oil, coal and ammunition and is replenished with fresh water.
11 February 1945:
At 1316, departs Naha still escorting convoy TAKA-604 and at 1855 arrives at Sesoko.
12 February 1945:
At 1713 departs Sesoko.
13 February 1945:
At 1430, detaches and at 1440, arrives at Seso. At 1827 arrives at Koniya and departs at 2305 escorting TAKA-600.
15 February 1945:
At 1353 arrives at Kagoshima. At 1806 the convoy departs Kagoshima and at 2100 arrives at Yamakawa.
16 February 1945:
At 1130 the convoy detaches. At 1158 arrives at Ushibuka.
20 February 1945:
At 0626 departs Ushibuka and at 1515 arrives at Kagoshima.
23 February 1945:
At 1424 departs Kagoshima with torpedo boat MANAZURU escorting convoy KANA-303 consisting of CHOKAI MARU and probably others.
24 February 1945:
At 0249 arrives at Koniya.
25 February 1945:
At 0219, departs Koniya. At 1325, diverted to Seso because of stormy weather
26 February 1945:
At 2019 departs Seso.
27 February 1945:
At 2030, detaches and at 2207 arrives at Naha.
28 February 1945:
Loads heavy oil and coal.
3 March 1945:
At 1143 departs Naha with auxiliary minesweepers TAIAN, CHITOSE MARUs, TAIHEI MARU No. 3 GO and BANSHU MARU No. 51 escorting convoy NAKA-303 consisting of CHOKAI, KOSHU and KASHIMA MARUs.
4 March 1945:
At 1140, detaches and heads towards Kuji Wan. At 1240 arrives at Kuji Wan and departs at 2020 escorting NAKA-203.
5 March 1945:
Off Akuseki Jima, Ryukyu Islands. At 1042, LtCdr (later Captain) Walter F. Schlech's (USNA ’36) USS TILEFISH (SS-307) torpedoes and damages W-15's stern at 29-36N, 129-45E. At 1047, confidential documents, wounded and passengers are transferred to BANSHU MARU No. 51. W-15 is beached on the shoal island of Suwasi with assistance from BANSHU MARU No. 51 to facilitate her salvage. Schlech fires two more torpedoes at W-15, but they explode on the reef.
6 ~ 9 March 1945:
Confidential documents, troops and weapons are transferred to BANSHU MARU No. 51, auxiliary minesweeper TAIYAN MARU and auxiliary subchaser YUSEN MARU No. 27. The crew is transferred to CD-68 and brought to Kagoshima. Thereafter W-15 is abandoned and later deemed a constructive total loss.
10 May 1945:
Removed from the Navy List.

Authors' Notes:
[1] Controversy surrounded the claims of who actually shot down Yamamoto. The late Captain (later Colonel, AFRes) Thomas G. Lanphier and Lt (later Colonel) Rex T. Barber both claimed credit. After reviewing the mission in 1960 and again in 1985, the U. S. Air Force officially shared the kill between the two pilots.
Thanks go to Mr. Aki of Japan and Matthew Jones of Ohio for help in identifying COs and to Mr. Gilbert Casse of France, Mr Berend van der Wal of Netherlands and Mr. Sander Kingsepp of Estonia for general assistance.
Photo credit goes to Maru Special via J. Ed Low.
-Bob Hackett and Peter Cundall.

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