Japanese Subchasers

KUSENTEI!

IJN Subchaser CH-15: Tabular Record of Movement
© 2005-2017 Bob Hackett, Sander Kingsepp and Peter Cundall
Revision 10

26 August 1940:
Osaka. Laid down as CH-182 at the Sakurajima Ironworks.
23 December 1940:
Launched and renumbered CH-15.
31 March 1941:
Completed and registered in the Yokosuka Naval District.
7 December 1941: Operation "M" - The Invasion of the Northern Philippines:
CH-15 is in Rear Admiral (later Vice Admiral) Kubo Kyuji’s (38) (former CO of KAGA) 1st Base Force of Vice Admiral Takahashi Ibo’s (35)(former CO of YAMASHIRO) Third Fleet. CH-15 is attached to Takahashi's Philippines Seizure Force in Cdr Nakamura's SubChasDiv 2 with CH-13 and CH-14. At 1630, departs Mako, Pescadores.

10 December 1941:
Beginning at 0550, participates in the landings at Aparri, Philippines. Led by Rear Admiral Hara Kezaburo (37) in Light Cruiser NATORI with destroyers ASAKAZE, HARUKAZE, HATAKAZE, MATSUKAZE (Desdiv 5), FUMITSUKI, MINATSUKI, NAGATSUKI and SATSUKI (DesDIv 22), minesweepers W-15, W-16 and W-19 (MineSweepDiv 11), auxiliary gunboats MANYO, TOMITSU and TAIKO MARUs (GunboatDiv 2) and subchasers CH-13, CH-14 and CH-15 (SubChaseDiv 2). CH-1 is in SubChaseDiv 1 consisting of CH-1, CH-2 and CH-3. The aircraft transport KEIYO MARU and five transports make up the landing force.
12 December 1941:
At 1800 departs Aparri with CH-13 and CH-14.
14 December 1941:
At 1130 arrives at Takao.
18 December 1941:
At 1400 departs Takao with CH-13 and CH-14.
24 December 1941:
With the Lamon Bay, Philippines invasion force. Arrives there at 0330.
28 December 1941:
At 1310 departs Lamon Bay with CH-14.
1 January 1942:
At 1130 CH-14 and CH-15 arrive at Davao.
6 January 1942:
At 1400 departs Davao with CH-14. Later at 1500 arrives Malalag Bay
7 January 1942:
At 1600 departs with CH-14 and at 1700 arrives at Malalag Bay.
9 January 1942:
At 0400 departs Malalag Bay with CH-13 and CH-14 on an anti submarine sweep.
13 January 1942:
At 1300 CH-13, CH-14 and CH-15 arrive at Davao.
14 January 1942:
At 1700 CH-13 and CH-15 depart Davao.
16 January 1942:
At 1100 CH-13 and CH-15 arrive at Banka.
22 January 1942:
At 1600 CH-13, CH-14 and CH-15 depart Banka.
24 January 1942:
At 0200 all arrive at Kendari.
27 January 1942:
At 1330 CH-13, CH-14 and CH-15 depart Kendari.
29 January 1942:
At 1530 all arrive back at Banka.
30 January 1942:
At 1200 departs Banka with CH-13.
2 February 1942:
At 0800 departs Banka.
5 February 1942:
At 1300 arrives at Kendari.
6 February 1942: The Invasion of Makassar, Celebes:
SubChasDiv 2’s At 2100 CH-14 and CH-15 depart Staring Bay with the Makassar Occupation Force consisting of six troop transports carrying Captain (later Vice Admiral) Mori Kunizo’s (40) Sasebo Combined Special Naval Landing Force (SNLF) escorted by light cruiser NAGARA, DesDiv 8’s ASASHIO, MICHISHIO, ARASHIO and OSHIO, DesDiv 15’s HAYASHIO, KUROSHIO, OYASHIO and DesDiv 21’s WAKABA, NATSUSHIO and NENOHI and MineSweepDiv 21’s W-7 and W-8.
9 February 1942:
At 0400 CH-14 and CH-15 arrive at Macassar.
16 February 1942:
At 0730 CH-14 and CH-15 depart Macassar.
18 February 1942:
At 1010 CH-14 and CH-15 arrive at Balikpapan.
20 February 1942:
At 1700 CH-13, CH-14 and CH-15 depart Balikpapan.
22 February 1942:
At 1140 arrives at Macassar.
23 February 1942:
At 1700 all depart Macassar.
25 February 1942:
At 0800 all arrive at Bali Island.

10 March 1942:
Assigned to Vice Admiral Takahashi's Southwest Area Fleet's newly formed Second Southern Expeditionary Fleet in Special Base Force 21.
15 May 1942:
Reassigned to the Yokosuka Guard Unit. Escorts convoys departing alternately from Shimoda and Nagaura bases.
28 May 1942:
At 1310 CH-13, CH-14 and CH-15 arrives at Nagaura.
30 May 1942:
At 1000 departs Nagaura.
20 July 1942:
Reassigned to SubChasDiv 5 in Vice Admiral Hosagaya Boshiro's (36) (former CO of MUTSU) Fifth Fleet based at Ominato, Northern Honshu.
27 July 1942:
At 0800 CH-13, CH-14 and CH-15 depart Yokosuka for Tokyo Bay and depart there at 1500.
29 July 1942:
At 1300 CH-13, CH-14 and CH-15 arrive back at Yokosuka.
August 1942:
Arrives at Kiska, Aleutians.
11 September 1942:
CH-13, CH-14 and CH-15 depart Kiska.
15 September 1942:
At 0900 the escorts arrive at Paramushiro.
20 November 1942:
Reassigned to the Yokosuka Guard Unit for the second time. Escorts convoys to Owase.
4 May 1943:
Probably departs Ujina for Yokosuka with torpedoboat MANAZURU escorting Auxiliary gunboat HAKKAI MARU (It is possible CH-15 joined at some later point).
5 May 1943:
About 60km south of Lake Hamana Lt.Cdr. E.T. Sands’s USS SAWFISH (SS-276) sights HAKKAI MARU escorted by a CHIDORI or OTORI class torpedo boat. At 1838 Sands fires 4 topedoes at her of which two hit.
At 1848 subchaser CH-15 drops 9 depth charges.
At 1850 HAKKAI MARU sinks at 34-10N, 137-35E. 121 members of the Nankai Detachment and three crewmen perish.
At 1854 subchaser CH-15 drops 8 depth charges.
At 1956 subchaser CH-15 makes 5 menacing drop charges.
At 2100 torpedoboat MANAZURU begins rescueing survivors.
At 2200 torpedoboat MANAZURU stops rescueing survivors, accomodates 121 survivors and heads towards Yokosuka. Subchaser CH-15 continues hunting for the enemy submarine. Torpedoboat MANAZURU arrives at Yokosuka later this evening.
May 1943:
Reassigned to the Fifth Fleet for the second time. Escorts convoys to the Kuriles.
15 June 1943:
Reassigned to the Ominato Naval District patrol unit. Meanwhile undertakes patrols off Paramushiro.
18 June 1943:
Arrives at Paramushiro Strait (Kataoka Wan).
19 June 1943.
Ceases patrols off Paramushiro Island. Later escorts convoys to the Hokkaido ports of Muroran and Wakkanai.
1 September 1943:
CH-15 meets convoy No. 2901 off Esan Misaki and escorts the ships partway south.
2 September 1943:
Arrives at Hachinohe.
3 September 1943:
Departs Hachinohe on patrol.
8 September 1943:
Arrives at Muroran.
9 September 1943:
Departs Muroran on patrol. Provides long distance escort cover to first SENZAN and HOKUSEI MARUs then SHINMEI, HAKUAI and SANTO MARUs.
11 September 1943:
Arrives at Odomari.
14 September 1943:
Departs Odomari on patrol.
16 September 1943:
Returns to Odomari.
18 September 1943:
Departs Odomari on patrol.
25 September 1943:
Returns to Odomari.
26 September 1943:
Departs Odomari on patrol.
29 September 1943:
Returns to Odomari.
2 October 1943:
Departs Odomari on patrol.
5 October 1943:
Arrives back at Odomari.
7 October 1943:
Departs Odomari on patrol.
11 October 1943:
La Pérouse/Soya Strait, Northern Japan. After completing a successful patrol in which he probably sinks four ships, Cdr Dudley W. Morton’s (USNA ’30) USS WAHOO (SS-238) is exiting the Sea of Japan on the surface, but leaving a trail of oil from a previous encounter. At about 0830, the spotter for a 6-inch coast artillery battery on Soya Misaki promontory sights USS WAHOO and opens fire. Morton submerges and continues on course. The battery commander calls for air support.
About an hour later, an E13A1 "Jake" anti-submarine floatplane No. 19, out of Wakkanai, arrives. At 0920, the Jake detects a widening oil slick, then sees the conning tower of a submarine. The E13A1's pilot drops two bombs on USS WAHOO. Two more E13A1s of the same unit arrive and drop a total of six depth-charges. At 1145, the first floatplane directs CH-15 to the scene. At 1203, the submarine is located and CH-15 drops two series of nine and seven depth-charges. Among the debris thrown up by explosions is a metal object that resembles the propeller blade of a submarine. At 1218, CH-15 drops a single depth-charge, then is relieved by CH-43. At 1221, CH-43 drops six depth-charges. At 1330, auxiliary minesweeper Wa-18 arrives. As a result of these attacks, USS WAHOO is sunk with all hands at 45-13N, 141-56E. [1]
12 October 1943:
Arrives back at Odomari.
13 October 1943:
Departs Odomari.
14 October 1943:
Arrives at Wakkanai.
15 October 1943:
Departs Wakkanai on an escort and patrol mission.
18 October 1943:
Arrives back at Odomari.
21 October 1943:
Departs Odomari on patrol.
23 October 1943:
Arrives at Wakkanai.
24 October 1943:
Departs Wakkanai on a patrol mission.
26 October 1943:
Arrives back at Odomari.
28 October 1943:
CH-15 departs Odomari for Ominato escorting a convoy consisting of NAGATA and EIHO MARUs.
29 October 1943:
At 0120, LtCdr Nicholas J. Nicholas' (USNA ’32) USS SALMON (SS-182) fires three torpedoes and gets two hits on NAGATA MARU, but both Mark XIV torpedoes are duds. A plane bombs USS SALMON without effect. CH-15 counterattacks and drops 11 depth-charges on USS SALMON, but Nicholas evades without damage. At sea, NAGATA MARU's crew repairs the holes punched in their ship's side and she continues on, stopping at two ports on Hokkaido.
At 0150, USN codebreakers intercept and decrypt a message from CH-15 that reads: “At 0130, received enemy submarine attack. Position ---- E, 45-32 N.”
31 October 1943:
CH-15 arrives back at Wakkanai.
2 November 1943:
Departs Wakkanai on an escort mission.
5 November 1943:
Arrives back at Wakkanai.
13 November 1943:
Departs Wakkanai on a patrol.
15 November 1943:
Arrives back at Wakkanai.
17 November 1943:
Departs Wakkanai on patrol.
18 November 1943:
Arrives at Odomari.
20 November 1943:
Departs Odomari on patrol.
21 November 1943:
Arrives at Odomari.
22 November 1943:
Departs Odomari on patrol.
23 November 1943:
Arrives at Odomari.
25 November 1943:
Departs Odomari on patrol.
27 November 1943:
Arrives back at Wakkanai.
2 December 1943:
Departs Wakkanai on patrol.
4 December 1943:
Arrives back at Wakkanai.
6 December 1943:
Departs Wakkanai on patrol.
7 December 1943:
Arrives at Odomari.
9 December 1943:
Departs Odomari on patrol.
12 December 1943:
Arrives back at Wakkanai.
15 December 1943:
Departs Wakkanai on patrol.
16 December 1943:
Arrives back at Wakkanai.
18 December 1943:
Departs Wakkanai on patrol.
19 December 1943:
Arrives back at Wakkanai.
22 December 1943:
Departs Wakkanai.
24 December 1943:
Arrives at Ominato and undergoes repairs.
13 January 1944:
Departs Ominato on patrol.
14 January 1944:
Arrives at Muroran.
15 January 1944:
Departs Muroran on patrol.
17 January 1944:
Returns to Muroran.
18 January 1944:
Departs Muroran on patrol.
21 January 1944:
Arrives at Muroran.
23 January 1944:
Departs Muroran on patrol.
25 January 1944:
Arrives at Muroran.
28 January 1944:
Departs Muroran on patrol.
29 January 1944:
Arrives at Muroran.
31 January 1944:
Departs Muroran on patrol.
1 February 1944:
Arrives back at Muroran.
3 February 1944:
Departs Muroran on patrol.
4 February 1944:
Arrives back at Muroran.
6 February 1944:
Departs Muroran on patrol.
7 February 1944:
Arrives back at Muroran.
9 February 1944:
Departs Muroran on patrol.
10 February 1944:
Arrives back at Muroran.
12 February 1944:
Departs Muroran on patrol.
13 February 1944:
Arrives back at Muroran.
14 February 1944:
Departs Muroran on patrol.
16 February 1944:
Arrives back at Muroran.
17 February 1944:
Departs Muroran on patrol.
18 February 1944:
Arrives back at Muroran.
20 February 1944:
Departs Muroran on patrol.
21 February 1944:
Arrives back at Muroran.
23 February 1944:
Departs Muroran on an escort mission.
24 February 1944:
Arrives back at Muroran. Departs later that day and arrives at Ominato.
4 April 1944:
Departs Muroran on patrol.
5 April 1944:
Arrives at Hakodate.
7 April 1944:
Departs Hakodate on an anti submarine sweep and patrol.
11 April 1944:
Arrives at Muroran.
12 April 1944:
Departs Muroran on patrol.
18 April 1944:
Arrives at Ominato.
3 May 1944:
Departs Muroran on patrol.
5 May 1944:
Arrives back at Muroran.
6 May 1944:
Departs Muroran on an anti submarine sweep and patrol.
9 May 1944:
Arrives at Hakodate.
11 May 1944:
Departs Hakodate on an anti submarine sweep.
12 May 1944:
Arrives back at Hakodate.
14 May 1944:
Departs Hakodate on patrol.
16 May 1944:
Arrives at Muroran.
18 May 1944:
Departs Muroran on an anti submarine sweep and patrol.
21 May 1944:
Arrives at Muroran.
22 May 1944:
Departs Muroran on patrol.
24 May 1944:
Arrives back at Muroran.
25 May 1944:
Departs Muroran on patrol.
27 May 1944:
Arrives back at Muroran.
29 May 1944:
Departs Muroran on patrol.
6 June 1944:
Arrives at Hakodate.
8 June 1944:
Departs Hakodate escorting a convoy consisting of Navy transport HOKUSHIN MARU (bound for Tennei) and Army cargo ship HOSHI MARU No.11 (JUICHISEI MARU) bound for Kushiro and Etorofu Island.
11 June 1944:
Arrives at Tennei.
14 June 1944:
Departs Tennei escorting a convoy.
17 June 1944:
Arrives at Odomari.
21 June 1944:
Departs Odomari on patrol.
22 June 1944:
Arrives at Otaru.
23 June 1944:
Departs Otaru escorting a convoy.
28 June 1944:
Arrives at Wakkanai.
29 June 1944:
At 1230 CH-15 departs Wakkanai and escorts a convoy consisting of MAYACHI MARU and UNKAI MARU No. 15 in the Sea of Okhotsk/southern Kuriles area.
1 July 1944:
At 0757 arrives at Wakkanai.
5 July 1944:
At 1200 departs Wakkanai escorting convoy KAKI-402 consisting of SENZAN and EIHO MARUs.
7 July 1944:
At 1510 arrives at Ominato.
10 July 1944:
Arrives back at Wakkanai.
13 July 1944:
At 0750 departs Wakkanai and joins convoy RA-303 consisting of tankers MITSU, MANJU and HAKUEI MARUs escorted by the destroyer NOKAZE and minesweeper W-23.
17 July 1944:
The convoy arrives at Oha (Okha). At latitude 50N W-23 and CH-15 have already been detached.
18 July 1944:
At 0925 arrives back at Wakkanai.
23 July 1944:
CH-15 departs Wakkanai.
25 July 1944:
CH-15 and kaibokan MANJU depart Oha (Okha) escorting the tanker MANJU MARU.
28 July 1944:
Arrives at Wakkanai.
1 August 1944:
CH-15 meets up with KI-102 consisting of KOKAI MARU and JUICHISEI MARU (HOSHI MARU No. 15) and escorts the ships towards Urup.
6 August 1944:
CH-15 is scheduled to detach from convoy KI-102 and head for Wakkanai after the convoy has passed Shiretoko and remain on standby from the moment minesweeper W-24 meets up with the convoy off the coast of Cape Soya until W-24 returns from Odomari, under instruction No. 70.
7 August 1944:
Arrives back at Wakkanai.
11 August 1944:
Departs Wakkanai on patrol.
14 August 1944:
Arrives back at Wakkanai.
16 August 1944:
At 2355 CH-15 departs Wakkanai escorting the tanker KANETSU (KANATSU) MARU bound for Oha (Okha), Sakhalin.
22 August 1944:
CH-15 arrives back at Wakkanai.
27 August 1944:
At 0749, CH-15 and minesweeper W-23 depart Wakkanai, northern Hokkaido for the Kuriles escorting convoy KI-203 consisting of MISAKI MARU No. 2 and EISHIN and HAKUSHU MARUs and two unidentified Marus.
29 August 1944:
At 1440, the convoy arrives at Tennei, Kuriles.
7 September 1944:
Departs Wakkanai on patrol.
9 September 1944:
Assigned to assist disabeld NAMIKAZE under instruction No. 79.
10 September 1944:
At 0800 arrives at N47.07-E148.16 and starts escorting KAMIKAZE and NAMIKAZE. CH-15 takes a position at the rear of the column.
12 September 1944:
Arrives at Cape Soya. Departs later and arrives at Odomari later that day.
E 13 September 1944:
Arrives at Tennei.
15 September 1944:
Departs Tennei on patrol.
17 September 1944:
Arrives back at Wakkanai.
22 September 1944:
Departs Wakkanai and later that day arrives at Otaru.
26 September 1944:
Departs Otaru.
27 September 1944:
Arrives at Ominato.
21 October 1944:
Departs Ominato escorting a convoy.
24 October 1944:
Arrives at Tennei.
26 October 1944:
Departs Tennei escorting a convoy.
29 October 1944:
Arrives at Ominato.
30 October 1944:
At 0800 CH-15 departs Ominato for Wakkanai.
1 November 1944:
Departs Wakkanai on patrol.
4 November 1944:
Arrives back at Wakkanai.
10 November 1944:
Departs Wakkanai on patrol.
13 November 1944:
Arrives back at Wakkanai.
18 November 1944:
Departs Wakkanai escorting tanker NANKO MARU No. 4, with minesweeper W-24 as an additional escort.
19 November 1944:
At an unknown location detaches from the convoy and begins patrolling.
22 November 1944:
Arrives back at Wakkanai.
27 November 1944:
Departs Wakkanai on patrol.
29 November 1944:
Arrives back at Wakkanai.
5 December 1944:
Departs Wakkanai on a training exercise.
7 December 1944:
Arrives back at Wakkanai.
10 December 1944:
Departs Wakkanai on patrol.
13 December 1944:
Arrives back at Wakkanai.
22 December 1944:
Departs Wakkanai on patrol.
25 December 1944:
Arrives back at Wakkanai.
2 January 1945:
Departs Wakkanai on patrol.
3 January 1945:
Arrives back at Wakkanai.
5 January 1945:
Departs Wakkanai on patrol.
6 January 1945:
Arrives back at Wakkanai.
9 January 1945:
Departs Wakkanai on patrol.
11 January 1945:
Arrives back at Wakkanai.
13 January 1945:
Departs Wakkanai on patrol.
15 January 1945:
Arrives back at Wakkanai.
18 January 1945:
Departs Wakkanai on patrol.
19 January 1945:
Arrives at Otaru.
22 January 1945:
Departs Otaru on patrol.
23 January 1945:
Arrives at Ominato. Operates patrols out of Ominato throughout February.
2 March 1945:
Departs Ominato but returns to port later that day.
10 March 1945:
Departs Ominato but returns to port later that day.
18 March 1945:
Departs Ominato but returns to port later that day.
22 March 1945:
Departs Ominato but returns to port later that day.
4 April 1945:
Departs Ominato on patrol.
6 April 1945:
Arrives at Kushiro.
8 April 1945:
Departs Kushiro on patrol.
9 April 1945:
Arrives at Ominato.
12 April 1945:
Departs Ominato.
13 April 1945:
Arrives at Muroran.
16 April 1945:
Departs Muroran escorting a convoy.
18 April 1945:
Arrives at Kushiro.
19 April 1945:
Departs Kushiro escorting a convoy.
20 April 1945:
Arrives at Tennei.
25 April 1945:
At 0330 with auxiliary minesweeper TAMAZONO MARU No. 1 departs Tennei escorting convoy KI-902 consisting of SHINTAI MARU No. 6 and an unidentified ship with No. 2 suffix.
26 April 1945:
At 2315 arrives at Kushiro.
27 April 1945:
Departs Kushiro escorting a convoy.
28 April 1945:
Arrives at Tennei.
4 May 1945:
Departs Abashiri.
5 May 1945:
At 0959 arrives at Kushiro after conducting an anti submarine sweep.
10 May 1945:
At 0800 CH-15 departs Kushiro escorting convoy KI-902 consisting of SHINTAI MARU No. 6 and NISSEN MARU No. 6.
12 May 1945:
At 0830 arrives at Tennei.
15 May 1945:
At 0300 the same ships depart Tennei.
16 May 1945:
At 1310 arrives at Kushiro.
19 May 1945:
At 0759 departs Kushiro escorting SHINTAI MARU No.6 and NISSEN MARU No. 6. At 1750 arrives at Nemuro.
20 May 1945:
At 0340 departs Nemuro and at 1600 arrives at Abashiri.
21 May 1945:
At 0945 the same convoy departs Abashiri.
23 May 1945:
At 1130 arrives at Wakkanai.
27 May 1945:
Departs Wakkanai on patrol.
29 May 1945:
Arrives back at Wakkanai.
18 June 1945:
At 1400, CH-15 and three unidentified coast defense ships depart Kataoka Bay, Shimushu Island in the Kuriles for Ominato escorting the “RU” Convoy transporting aviation gasoline and consisting of HAKUAI and ZAOSAN MARU. At 1920, that same day the convoy is intercepted by three surfaced submarines. LtCdr Arthur C. House's (USNA ’34) USS APOGON (SS-308) fires 10 torpedoes from close range and sinks both HAKUAI and ZAOSAN MARUs. HAKUAI MARU is fully loaded with 139 tons Army goods, war supplies and about 280 passengers of whom 39 are killed. ZAOSAN MARU loses seven passengers and 49 of the crew KIA. CH-15 rescues 192 survivors.
19 June 1945:
At 0117, USN codebreakers intercept and decrypt a message from CH-15 to an unidentified station that reads: “Pick up survivors of HAKUAI (Hiroi) MARU --.”
At 0700, CH-15 returns to Kataoka Bay and puts the survivors ashore.
15 August 1945:
Yokosuka. CH-15’s crew learns of the termination of the war.
30 November 1945:
Removed from the Navy List.
1 November 1946:
Appointed a special cargo ship in the Allied Repatriation Service, but is inactive because her machinery is out of commission.
23 April 1948:
CH-15 is sold for scrap.

Authors' Note:
[1] Morton was posthumously awarded a fourth Navy Cross. He and USS WAHOO sank 19 cargo and transport ships for a total of 55,000 tons.
Thanks go to John Whitman of the USA for info on CNO intercepts of Japanese messages and to Mr. Gilbert Casse of France.

-Bob Hackett, Sander Kingsepp and Peter Cundall.

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