IJN Subchaser CH-33:
Tabular Record of Movement
© 2005-2015 Bob Hackett, Sander Kingsepp and Peter Cundall
Tamano. Laid down at the Mitsui Engineering & Shipbuilding shipyard.
18 May 1942:
Launched and numbered CH-33.
15 August 1942:
Completed and registered in the Yokosuka Naval District.
20 August 1942:
At 1815 arrives at Nagaura.
25 August 1942:
At 0515 departs Nagaura.
27 August 1942:
At 1715 arrives at Nagaura.
29 August 1942:
At 1200 departs Nagaura with auxiliary netlayer AGATA MARU No. 2.
Assigned to the Yokosuka Guard Unit. Patrols Tokyo Bay and escorts convoys in the Aomori, Iwate, and Miyagi Prefecture areas.
2 September 1942:
At 0750 CH-32 and CH-33 arrive at Nagaura.
4 September 1942:
At 0840 departs Nagaura.
14 September 1942:
At 0730 arrives at Nagaura.
17 September 1942:
At 1340 departs Nagaura.
21 September 1942:
At 1535 arrives at Nagaura.
23 September 1942:
At 0745 departs Nagaura.
24 September 1942:
At 1750 arrives at Nagaura.
26 September 1942:
At 1215 departs Nagaura.
28 September 1942:
At 1630 arrives at Nagaura.
18 December 1942:
CH-33 arrives in Tokyo Bay escorting West convoy No. 72 from the Inland Sea area consisting of KACHIDOKI (ex American PRESIDENT HARRISON), NICHIREN and KOZUI MARUs.
30 December 1942:
CH-33 departs Tokyo Bay escorting North Convoy No. 81 consisting of SHIGANOURA and KIMISHIMA MARUs bound for Muroran and SHINYO MARU No.8 bound for Shiogama.
E 22 January 1943:
22 January 1943:
At 1600 off the coast of Sunosaki joins patrol boat PB-31 and starts escorting auxiliary oiler NISSHIN MARU. Near the 33 degree north latitude PB-31 ends the escort.
23 January 1943:
At 0030 near the 34 degree north latitude in stormy weather looses contact with NISSHIN MARU.
19 February 1943:
At 1400 CH-33 departs Yokohama escorting convoy 1219B consisting of MAYACHI, SUMIRE and NIKKIN MARUs and one unidentified merchant ship all bound for Muroran.
Reassigned to the 4th Base Force at Truk. Escorts convoys between Truk and Palau.
1 April 1943:
At 1000 CH-33 departs Tokyo Bay escorting NANYO MARU No. 1 to Saipan.
8 April 1943:
At 0645 arrives at Saipan.
10 April 1943:
At 0500 departs Saipan on an escort mission.
13 April 1943:
At 1040 arrives at Truk.
20 April 1943:
At 1200, CH-33 departs Truk escorting a convoy to Palau consisting of MEITEN and SANSEI MARUs and oiler KYOEI MARU.
26 April 1943:
At 0800, the convoy arrives at Palau.
7 May 1943:
At 0600 departs Palau escorting ONOE MARU.
10 May 1943:
At 1121 arrives at Truk.
15 May 1943:
At 1445 departs Truk on patrol.
19 May 1943:
At 1430 arrives back at Truk.
24 May 1943:
At 1200 CH-33 departs Truk escorting convoy No. 1242 consisting of NANKAI MARU No. 2 and HOKKAI and MANKO MARUs.
29 May 1943:
At 1630 arrives at Rabaul.
1 June 1943:
At 1600 departs Rabaul in convoy 2012 escorting GOSHU and KAGU MARUs.
4 June 1943:
At 1235 arrives at Truk.
8 June 1943:
At 1600 departs Truk escorting MUKO MARU and possibly others.
12 June 1943:
At 1020 arrives at Rabaul.
13 June 1943:
Departs Rabaul on an escort mission.
19 June 1943:
At 1045 arrives at Truk.
22 June 1943:
Departs Truk with the destroyer MIKAZUKI escorting convoy 1212 consisting of tanker NICHIEI MARU and one unidentified merchant ship.
27 June 1943:
At 0800 departs Rabaul with CH-16 in convoy No. 2272 escorting MIKAGE MARU No. 20 and NANKAI MARU No. 2.
1 July 1943:
At 1045 arrives at Truk.
4 July 1943:
At 0900 departs Truk escorting convoy 1041 believed to consist only of SHINSEI MARU No. 17.
8 July 1943:
At 0600 arrives at Rabaul.
9 July 1943:
At 1200 departs Rabaul escorting convoy No. 2092 consisting of CHIHAYA (ex Dutch TJISAROEA) and SHOEI MARUs.
13 July 1943:
At 1000 arrives at Truk.
15 July 1943:
At 0830 departs Truk escorting convoy 5152 consisting of KENAN and KIKUKAWA MARUs.
20 July 1943:
At 1300 arrives at Kwajalein.
23 July 1943:
At 0400 departs Kwajalein on an escort mission to Wake Island.
27 July 1943:
At 1300 arrives at Wake Island.
30 July 1943:
At 0600 departs Wake Island on an escort mission to Kwajalein.
4 August 1943:
Arrives at Kwajalein.
5 August 1943:
At 0400, CH-33 departs Kwajalein escorting convoy 6053 making 11.5 knots and consisting of SANTOS, MITAKESAN and KAISHO MARUs.
9 August 1943:
At 1100, arrives at Truk's north channel.
13 August 1943:
CH-29 and CH-33 depart Truk escorting convoy No. 1133 consisting of TOKYO and TOYU MARUs and one unidentified merchant ship.
17 August 1943:
Arrives at Rabaul.
19 August 1943:
CH-29 and CH-33 depart Rabaul escorting convoy No. 2194 connsisting of the tanker GENYO MARU and three unidentified merchant ships.
23 August 1943:
Arrives at Truk.
26 August 1943:
Departs Truk escorting Convoy No. 7826 consisting only of EIKO MARU No. 2 Go bound for Palau.
30 August 1943:
Arrives at Kavieng.
31 August 1943:
2 September 1943:
At 0600, CH-33 departs Palau for Wewak, New Guinea escorting convoy "Wewak No. 8" consisting of TENKAI and SHINSEI MARUs.
5 September 1943:
At 1312, TENKAI MARU is hit by one of four torpedoes fired by LtCdr (later Captain) Frank M. Parker's (USNA ’32) USS SWORDFISH (SS-193). TENKAI MARU, carrying 60 troops, a cargo of ammunition, gasoline and automobiles, is set afire and at 1420 sinks at 01-10N, 142-10E. Three crewmen and three passengers are killed. CH-33 counterattacks and drops 10 depth charges, but USS SWORDFISH escapes.
7 September 1943:
Arrives at Wewak.
13 September 1943:
Arrives at Palau.
14 September 1943:
Departs Palau with destroyer OITE escorting convoy No. 8142 consisting of tankers NISSHO and KUMAGAWA MARUs to Truk.
19 September 1943:
Arrives at Truk and undergoes repairs.
8 October 1943:
At 0600, CH-33 departs Truk escorting convoy 7081 consisting of oiler SHINSHU MARU and KENSHO MARU.
13 October 1943:
Arrives at Palau.
15 October 1943:
Departs Palau escorting convoy No. 8152 consisting of two unidentified ships.
21 October 1943:
Arrives at Truk.
23 October 1943:
Departs Truk escorting convoy 1232 consisting of HOKUYO MARU and one unidentified merchant ship to Rabaul.
29 October 1943:
Arrives At Rabaul.
30 October 1943:
Departs Rabaul escorting convoy 2302 consisting of YAMAGIRI and NIKKO MARUs to Truk.
4 November 1943:
At 1000 arrives at Truk.
6 November 1943:
At 0600, CH-33 escorts SHOTAN MARU through Truk's South Passage into the lagoon. At 1600, Naval tanker ONDO and CH-33 depart Truk by S channel. Later that day, CH-33 is detached and diverted to assist tanker GENYO MARU and destroyer YAKAZE that collided. Both return to Truk. Auuxiliary minelayer KINJO MARU, part of the original escort; and cable layer escort TATEISHI and auxiliary minesweeper NOSHIRO MARU No.2 (both sent out from Truk) also assist in support roles. CH-33 then sails on to Palau and joins up with ONDO en route.
13 November 1943:
Arrives at Palau.
17 November 1943:
At 0950, CH-33 and auxiliary subchaser CHa-27 and destroyer AMATSUKAZE depart Palau escorting convoy 8175 consisting of oilers TSURUMI, SATA, SEIAN MARU, KYOEI MARUs and tanker ex cargo ship SHOYU MARU. About 1400, an unidentified submarine is detected. The escorts conduct an unsuccessful depth charge attack.
20 November 1943:
At 2000, CHa-27 detaches and returns to Palau.
24 November 1943:
At 0840, arrives at Truk.
27 November 1943:
At 0600, CH-33 and torpedo boat OTORI depart Truk escorting fleet convoy 1272 to Rabaul consisting of KONEI and HAGURO MARUs.
1 December 1943:
At about 0715, KONEI MARU is hit by three of six torpedoes fired by LtCdr (later Rear Admiral) William T. Nelson's (USNA ’30) USS PETO (SS-265). KONEI MARU sinks at 01-16N, 146-45E. 39 crewmen are KIA. CH-33 and OTORI counterattack and drop 12 depth charges, but USS PETO evades undamaged.
4 December 1943:
At 1135, arrives at Rabaul.
6 December 1943:
At midnight, CH-33 and CH- 29 depart Rabaul escorting convoy 2063 consisting of HAKUSAN, KOKAI and TETSUYO MARUs.
9 December 1943:
At 0945, TETSUYO MARU develops engine trouble and falls behind. CH-33 is detached to escort.
10 December 1943:
At 0650, the convoy arrives at Truk.
11 December 1943:
CH-33 departs Truk on an anti submarine sweep.
15 December 1943:
Arrives back at Truk.
22 December 1943:
At 0830, CH-33 departs Truk to Palau escorting fleet convoy 7222 consisting of KYOEI and SHINSHU MARUs.
27 December 1943:
Arrives at Palau at 1400 after weathering bad storms at sea.
E 30 December 1943:
CH-33 escorts convoy O-706 consisting of SHIRANESAN, RYUA, HARUNA, HOKKAI and HIDAKA MARUs and KOSHU MARU No. 3, also escorted by CH-39.
31 December 1943:
At 1800, CH-33 joins convoy 2614 at sea. The convoy departed Balikpapan, Borneo on 26 December and consists of OGURA MARU No. 3 escorted by patrol boat PB-2.
3 January 1944:
At 0730, CH-33, CH-24 and CH-39 depart Palau escorting convoy 8031 consisting of oiler OGURA MARU No. 3.
9 January 1944:
Arrives at Truk.
10 January 1944:
Departs Truk and undertakes an anti submarine sweep.
12 January 1944:
Arrives back at Truk.
16 January 1944:
Departs Truk on an escort mission.
18 January 1944:
Arrives back at Truk.
20 January 1944:
CH-33 departs Truk with destroyer HAMANAMI and CH-24, CH-30 and CH-39 depart Truk escorting a convoy consisting of oiler OGURA MARU No. 3. The ship then conducts an antti submarine sweep.
23 January 1944:
Arrives back at Truk.
24 January 1944:
CH-33 and destroyer SUZUKAZE depart Truk for Eniwetok escorting a convoy consisting of auxiliary transport OKITSU and auxiliary water tanker NIPPO MARUs to Ponape.
25 January 1944:
N of Ponape. At 2305, SUZUKAZE is hit and sunk with most of her crew including her CO, Commander Yamashita Masao (52), by two torpedoes fired by LtCdr (later Cdr) George G. Molumphy's (USNA ’31) old USS SKIPJACK (SS-184). CH-33 commences an unsuccessful search for the submarine, then rescues 22 survivors while OKITSU and NIPPO MARUs clear the area.
26 January 1944:
LtCdr Molumphy again attacks the convoy and, at 0305, he hits OKITSU MARU in hold No. 4. She floods and begins sinking by the stern. Abandon Ship is ordered. At 0340, OKITSU MARU carrying 518 personnel of the 221st Navy Construction Unit and 86 civilian workers, sinks at 09-24N, 157-45E taking down 169 Navy passengers and seven crewmen.
27 January 1944:
Arrives at Ponape.
29 January 1944:
Departs Ponape on an escort mission to Truk (likely escorting auxiliary water tanker NIPPO MARU).
7 February 1944:
Departs Ponape escorting a convoy consisting of auxiliary water tanker NIPPO, and YUBAE and KITAGAMI MARUs with TAKUNAN MARU No. 2 and SHONAN MARU No. 5 (some may have joined en route).
10 February 1944:
Lt Abe Takao's CH-33 arrives at Truk escorting a convoy consisting of auxiliary water tanker NIPPO, and YUBAE and KITAGAMI MARUs with TAKUNAN MARU No. 2 and SHONAN MARU No. 5.
12 February 1944:
Departs Truk on an escort mission to Ponape.
15 February 1944:
Departs Ponape on an escort mission to Truk.
17-18 February 1944: American Operation "Hailstone" - The Attack on Truk:
Beginning at dawn, Vice Admiral (later Admiral) Marc A. Mitscher’s (USNA ’10) Task Force 58's five fleet carriers and four light carriers, supported by six battleships, ten cruisers and 28 destroyers, launch air attacks on airfields, shore installations and ships in the lagoon. Mitscher launches 30 strikes of at least 150 aircraft each. The strikes are launched about every hour.
In two days of raids, Task Force 58 sinks 31 transports and 10 naval vessels (two cruisers, four destroyers and four auxiliary vessels, destroys nearly 200 aircraft and damages severely about 100 more. Truk is eliminated as a major fleet anchorage for the IJN. CH-33, that arrives back from Ponape on the 17th is damaged in the raid. The warship remains at Truk for the rest of the month.
23 February 1944:
On that day, FRUMEL decrypts the following order transmitted by Truk Base Force:
"Subchasers 5, 31 and 33 attack the submarine inside the reef with depth charges and force her to the surface. Subchaser 28 is to proceed to the atoll off Sarashima and Hanashima Channels and cut off line of escape."
1 March 1944:
Departs Truk on an escort mission.
5 March 1944:
Returns to Truk.
6 March 1944:
Departs on an escort mission to Palau
10 March 1944:
Arrives at Palau.
11 March 1944:
Departs Palau on an escort mission to Saipan.
14 March 1944:
Arrives at Saipan.
15 March 1944:
Departs Saipan on an escort mission to Yokosuka.
25 March 1944:
Arrives at Yokosuka and undergoes repairs.
Reserve LtCdr Kuwahara Tadao (former Chief Navigator, CHUYO) assumes command from Lt Abe.
29 May 1944:
At dawn, CH-33, CH-17, CH-50 and torpedo boat OTORI depart Tokyo escorting convoy 3530 consisting of TAKAOKA, SHINROKU, TAMAHIME, KASHIMASAN, HAVRE, SUGIYAMA, KATSUKAWA, KATORI MARUs and two other unidentified ships carrying troops of the 43rd Infantry Division.
4 June 1944:
At 1530, KATSUKAWA MARU is torpedoed and sunk by LtCdr (later KIA) Edward N. Blakely's (USNA ’34) USS SHARK (SS-314) at 19-45N, 138-15E. 28 troops, 10 guards and 77 crewmen are killed.
5 June 1944:
At 1645, at 18-40N, 140-35E, TAKAOKA MARU with 3,500 troops aboard, is torpedoed and sunk by Blakely's USS SHARK. 115 troops and 29 of the crew are killed. Immediately afterwards by TAMAHIME MARU sunk in the same position also by USS SHARK. 52 of her crew are killed.
6 June 1944:
At 1000, LtCdr (later Admiral, CINCPACFLT) Bernard A. Clarey's (USNA ’34) USS PINTADO (USS-387) torpedoes and sinks KASHIMASAN MARU loaded with aviation gasoline, ammunition, weapons and boatsat 16-28N, 142-16E. 43 of the crew are killed. At 1010, Clarey sinks HAVRE MARU in the same position. Seven out of the 2816 troops aboard and 91 crewmen are KIA.
7 June 1944:
SUGIYAMA MARU is torpedoed and damaged by LtCdr (later Captain) James B. Grady's (USNA ’33) USS WHALE (SS-239) at 31-06N, 142-34E and returns to Yokosuka. Later that day, the remaining ships arrive at Saipan.
11 June 1944:
Fear of an imminent Allied landing causes all navigable ships in Saipan to flee. At 0400, CH-33, CH-50, CH-51, auxiliary submarine chasers TAKUNAN MARU No. 8, CHa-20, CHa-50, auxiliary minesweeper Wa-6, torpedo boat OTORI and kaibokan CD-4 depart escorting makeshift convoy 4611 consisting of MOJI, FUKOKU, BATAVIA, TENRYUGAWA, TATSUTAGAWA, KOKKO (auxiliary netlayer), IMIZU, SHINTO, HINKO, BOKUYO, KEIYO, NITCHO, REIKAI, MAMIYA, INARI MARUs, NISSHO MARU No. 1 and 16 other unidentified ships.
12-14 June 1944:
Mariana Islands area, Aircraft of Vice Admiral (later Admiral) Marc A. Mitscher’s (USNA ’10) Task Force 58 attack facilities and shipping in preparation for the landings on Saipan. TG 58.4’s carriers USS ESSEX (CV-9), USS LANGLEY (CVL-27) and USS COWPENS' (CVL- 25) decimate CD-4’s convoy. They sink torpedo boat OTORI(casualties unknown), and merchant ships KOKKO (two crewmen KIA), BATAVIA (59 crewmen and 18 passengers KIA), HINKO (nine crewmen and 12 passengers KIA), KAMISHIMA (SHINTO) (53 crewmen and 54 passengers KIA), IMIZU (67 crewmen KIA), NITCHO (14 crewmen KIA), REIKAI (40 crewmen and 42 passengers KIA), TENRYUGAWA (seven crewmen KIA), BOKUYO (45 crewmen KIA), FUKOKU (51 crewmen and 31 passengers KIA), MOJI (53 crewmen and 5 gunners KIA), KEIYO (casualties unknown) MARUs and and damage TATSUTAGAWA MARU (15 crewmen and two passengers KIA), CD-4, CH-33, CH-50 and CH-51, CHa-20 and Wa-6. CD-4 is repeatedly strafed and develops a leak after several near misses. Eight sailors are lost and 29 wounded.
TATSUTAGAWA MARU is left drifting and finished off by gunfire three days later. MAMIYA MARU is detached and sunk three days later near Iwo Jima with seven crewmen KIA.
An unknown officer assumes command. LtCdr Kuwahara is reassigned to kaibokan UKURU as Chief Technician and later CO.
17 July 1944:
At 0755 departs Kure in a convoy also consisting of RYOEI, AZUSA and OKIGAWA MARUs escorted by destroyers SATSUKI, YUZUKI and UZUKI, kaibokan MANJU and submarine chasers CH-30 and CH-33. It is possible KOKUYO MARU was also in this convoy (TROM conflict)
20 July 1944:
At an unknown location, refuels subchaser CH-33.
23 July 1944:
At 0847 arrives at Manila. RYOEI MARU (and some escorts) arrived later. NICHIEI MARU then provides bunker fuel to CH-33 and also CH-30.
30 July 1944:
125 miles W of Jolo. At about 0100, oiler KOKUYO MARU which is being escorted by kaibokan CD-22 and submarine chasers CH-30 and CH-33 en route from Manila to Balikpapan and Macassar, is attacked by LtCdr (later Cdr) Lawrence L. Edge's (USNA ’35) USS BONEFISH (SS-223). Hit by four of five torpedoes Edge fires in a night surface radar attack. The tanker blows up and sinks by the stern at 06-03N, 120-00E. Nine crewmen are killed.
CH-33 is reassigned to the Southwest Area Fleet.
E 8 August 1944:
CH-33 joins BINGO MARU convoy consisting of BINGO, SHINSEI and OSEI MARUs escorted by minesweeper W-30 and auxiliary submarine chaser KYO MARU No. 12. KYO MARU No. 12 and W-30 are called away to assist torpedoed YAMATAMA MARU.
9 August 1944:
At 0007 arrives at Malalag and CH-33 apparently is detached.
11 August 1944:
At 2100, CH-33 and CH-30 depart Manila escorting the Miri leg of convoy MI-13 that consists of SHOEI, HIYORI, KUNIYAMA, URAL, SHINSEI MARU No.1, HIGANE MARUs and oilers SHINCHO, SHINPO, ZUIYO, TEIKON, OGURA MARU No. 2, TOKUWA, KYOEI and ATAGO MARUs also escorted by kaibokan CD-4, and Patrol Boat No. 38.
12 August 1944:
At 0730, Cdr Frank G. Selby's (USNA ’33) USS PUFFER (SS-268) torpedoes and sinks SHINPO MARU at 13-18N, 120-11E. 20 crewmen are KIA. At 0733, Selby torpedoes and sinks TEIKON MARU (ex German WINNETOU) at the same location without loss of life. The convoy shelters in Paluan Bay, NW Mindoro.
14 August 1944:
At 0700, departs Paluan Bay.
16-17 August 1944:
CH-33 splits off and joins the escort of convoy MI-12 that left Miri at 0700 on 16 August consisting of TAKETOYO, NORFOLK, UGA, KINRYU, GYOKUYO, GYOSAN MARUs, JUNGEN GO and an unknown ship called KAITO MARU and tankers ZUIYO, JINEI, SEISHIN and NANSEI MARUs escorted by kaibokan SHIMUSHU, CD-7, CD-16, CD-28 and subchasers CH-30 and CH-41. 
18 August 1944:
At 1352, LtCdr (later Rear Admiral-Ret) William T. Kinsella's (USNA ’34) USS RAY (SS-271) torpedoes and sinks NANSEI MARU (ex British PLEIODON) at 08-39N, 116-39E. Three Gunners and 23 crewmen are killed. The convoy is ordered to seek shelter.
20 August 1944:
At 1930, arrives at Paluan Bay, NW Mindoro.
21 August 1944:
At 0556, departs Paluan Bay. Soon after kaibokan CD-28 attacks an enemy submarine contact. At 0720, a wolfpack consisting of USS RAY, USS GUITARRO, USS HADDO, USS HARDER and USS MUSKALLUNGE begin the first of a series of successful attacks.
At 0720, LtCdr (later Rear Admiral-Ret) Kinsella's (USNA ’34) USS RAY torpedoes and sinks TAKETOYO MARU carrying a cargo of drummed oil and gasoline at 13-23N 120-19E. 13 crewmen are KIA. At 0730, LtCdr (later Rear Admiral-Ret) Chester W. Nimitz Jr's (USNA ’36) USS HADDO (SS-255) torpedoes and sinks NORFOLK MARU in the same position. One Gunner and 16 crewmen are KIA.. At 0800, Nimitz torpedoes and sinks KINRYU MARU carrying a cargo of bauxite at 13-20N, 120-17E. 65 of soldiers and three crewmen are KIA At 0825, LtCdr (later Captain) Enrique D. Haskins' USS GUITARRO (SS-363) torpedoes and sinks UGA MARU at the same location. 96 of the passengers, two ship’s gunners and 29 crewmen on UGA MARU are killed.
22 August 1944:
At 2200, arrives at Manila.
6 September 1944:
At 0748, destroyer SATSUKI, CH-33 and CH-30 depart Singapore in the Kamoi convoy consisting of Naval oiler KAMOI and oilers KYOKUTO and OKIGAWA MARUs.
7 September 1944:
SATSUKI and CH-33 detach to carry out an anti-submarine sweep.
8 September 1944:
At 0325, rejoins convoy. At 1030, OKIGAWA MARU and CH-33 detach for Miri. At 1858, the rest of the convoy arrives at Miri.
9 September 1944:
At 0722, CH-28, CH-30 and CH-33 and destroyer SATSUKI depart Miri escorting a revised convoy consisting of KYOKUHO and KYOKUTO MARUs. Thirty minutes after leaving, KYOKUHO MARU suffers engine problems and returns to port. At 1117, CH-28 returns to Miri. At 1903, the convoy anchors in Brunei Bay.
10 September 1944:
At 1252, departs Brunei Bay.
11 September 1944:
At 1945, arrives at Culusian Bay.
12 September 1944:
At 0640, departs Culusian Bay. At 1842, arrives at Boayan Island, NW Palawan. Delayed there on orders.
13 September 1944:
Boayan Island. KYOKUTO MARU refuels CH-33 (15 tons) and CH-30 (9 tons) with No.1 grade fuel oil.
19 September 1944:
At 0652, departs Boayan Island. At 1845, arrives at Talampulan Island, Busuanga and meets with oiler KAMOI.
20 September 1944:
AAt 0617, departs Talampulan Island. En route the ships are met at 12-59N 120-06 by auxiliary subchaser CHa-60. At 2122, the convoy arrives at Manila.
21 September 1944:
During a major carrier air raid on Manila, KYOKUTO MARU is sunk, but CH-33 escapes serious damage.
6 October 1944:
At 0618, CH-33, CH-28, CH-30 and CH-41 depart N San Fernando as part of the escort of combined convoys MATA-28 and MIMA-11 consisting of KOHOKU, HOKUREI, BUNZAN, SHOEI, HOKUSEN, TERUKUNI, HISHIGATA, OMINE MARUs, SHINYO MARU No. 8, and tankers TACHIBANA MARU, KAMOI and YAMAMIZU MARU No. 2 escorted by kaibokan CD-8, CD-25 and CD-32 and minesweeper W-20.
At about 0800, LtCdr Henry C. Stevenson's (USNA ’30) USS ASPRO (SS-309) attacks the convoy. Stevenson fires three torpedoes by periscope at an oiler and claims one hit, but actually achieves no results. At 1530, LtCdr William C. Thompson's (USNA ’35) USS CABRILLA (SS-288) torpedoes HOKUREI MARU and YAMAMIZU MARU No. 2. YAMAMIZU MARU No. 2 sinks at 17-30N, 120-9E with the loss of 56 crewmen. Only two survivors are rescued. HOKUREI MARU, badly damaged, is beached off Vigan. Five passengers and four crewmen are killed in the torpedo attack. The convoy seeks shelter in Lapoc Bay, arriving at 1830.
7 October 1944:
At 0030, the rest of convoy departs except for TERUKUNI, OMINE MARUs and SHINYO MARU No. 8 and probably CH-33 and CH 30 that remain behind at Lapoc Bay.
27 October 1944:
At 1958, CH-33 and CH-30, auxiliary subchaser CHa-41 and minesweeper W-20 depart Hong Kong escorting convoy HOMA-01 consisting of HAMBURG, YASUKUNI, SHINETSU and KANSHU MARUs, NISSHO MARU No. 18 and oiler EIWA MARU.
30 October 1944:
CH-33 arrives at Takao escorting SHINETSU MARU separately from the rest of the convoy.
23 November 1944:
At 1200, CH-33, patrol boats PB-38 and PB-102 (ex-USS STEWART, DD-224) depart Manila for Takao escorting convoy MATA-34 consisting only of MANJU MARU.
24 November 1944:
Luzon Strait, 100 miles N of Cape Engano. LtCdr (later Rear Amiral/COMSUBPAC) John H. Maurer’s (USNA ’35) submerged USS ATULE (SS-403) sights a transport and three escorts heading NW toward Sabtang Island. At dark, Maurer surfaces and sets course so as to intercept the transport shortly after midnight.
25 November 1944:
At about 0125, as Maurer is setting up on the transport, one of her escorts also moves into periscope view. He fires six bow tubes at the overlapping targets, then turns the boat about and fires his two stern tubes. USS ATULE scores two hits on each target. Patrol boat PB-38 (ex-DD YOMOGI) disintegrates. MANJU MARU is hit aft in hold No. 5 and goes dead in the water.
USS ATULE withdraws as CH-33 and patrol boats No. 102 search the area. At 0516, MANJU MARU sinks by the stern at 20-14N, 121-40 E. Twenty-four of her crew and about 700 of 1300 troops on board are KIA.
3 December 1944:
Departs Takao in convoy TAMA-34 consisting of JINYO, KENJO, YAMAKUNI, FUKUYO and YASUKUNI MARUs, BANSHU MARU No. 31 and SHINFUKU MARU escorted by destroyer KURETAKE, kaibokan CD-28, CD-54 and CH-33 as well as two unidentified escorts.
6 December 1944:
At 2147, a concerted wolfpack attack begins by Cdr (later Rear Admiral) Roy M. Davenport's (USNA ’33) USS TREPANG (SS-412) and LtCdr James D. Fulp's (USNA ’34) USS SEGUNDO (SS-398).
Davenport torpedoes and sinks JINYO MARU with troops, depth charges, boats and possibly tanks aboard, at 18-30N 121-57E with 1,383 troops and 44 crewmen lost. At 2237, Fulp torpedoes YASUKUNI MARU, loaded with 315 troops, 155 passengers, coal, military vehicles and tanks; that runs aground and is later abandoned near 18-59N 120-56E. Three troops on lookout and 25 crewmen are killed. At 2358 Davenport hits FUKUYO MARU with three torpedoes. She blows up and sinks nearby. At the time the ship was carrying the 18th Naval Strike Group in four parties consisting of 921 men, of which 913 together with 66 ship’s gunners and 94 of the crew are KIA. BANSHU MARU No. 31 is also sunk with no survivors from her crew of 23 around this time at 18-54N, 120-49E.
7 December 1944:
At 0005, Fulp's USS SEGUNDO torpedoes and sinks KENJO MARU at 18-52N, 121-57E. The ship is carrying Naval troops and the Southern Special Intelligence Unit, a total of 379 men as well as freight. The survivors are forced to escape into dark stormy seas and float in the water for many hours until early next morning when rescue began. Many people died including 78 of the crew. Meanwhile YAMAKUNI MARU, damaged by Davenport's USS TREPANG, goes no further than N San Fernando.
9 December 1944:
SHINFUKU MARU arrives at Manila with escorts less kaibokan CD-54 that is detached to rescue YASUKUNI MARU.
5 February 1945:
At 1200 CH-33 and CH-35 depart Singapore escorting EIFUKU MARU, carrying 350 Naval Marines as well as war supplies.
8 February 1945:
EIFUKU MARU is torpedoed and sunk by LtCdr Paul E Summers' (USNA 36) USS PAMPANITO in position 07-05N 104-50E. 335 Naval Marines and four crewmen are KIA.
9 February 1945:
The escorts arrive at Saigon.
17 February 1945:
Departs Saigon on an escort mission in the South China Sea escorting two unidentified ships (possibly Naval transports T-131 (KUROSHIO No. 1) and T-149 (KUROSHIO No. 2)).
5 March 1945:
CH-33 departs Singapore for Moji with CH-9, minesweeper W-4, ASW detection vessel TATEISHI (fitted with special cable to detect submerged subs), auxiliary subchaser ex netlayer KAINAN MARU and auxiliary subchaser NITTO MARU No. 17 escorting convoy HI-88-I consisting of KOGA, YAMAKUNI and HOSEN MARUs, NANSHIN MARU No. 21, FUSHIMI MARU No. 2, TAKASAGO MARU No. 6 and GENZAN (MOTOYAMA) MARU No. 1.
15 March 1945:
Arrives at Cape St. Jacques, Indochina. The convoy is reorganized. KOGA MARU is detached. W-4 probably is detached and returns to Singapore.
19 March 1945:
CH-9 departs Cape St. Jacques with CH-33, cable-layer TATEISHI, auxiliary subchaser KAINAN MARU and subchaser CH-20 escorting convoy HI-88-I now consisting of HOSEN MARU, FUSHIMI MARU No. 2, GENZAN (MOTOYAMA) MARU No. 1, NANSHIN MARU No. 21 and TAKASAGO MARU No. 6. >
20 March 1945:
50 miles S of Camranh Bay, Indochina. At about 0100, convoy HI-88J is attacked by LtCdr Benjamin C Jarvis' (USNA ’39) USS BAYA (SS-318). Jarvis torpedoes and sinks KAINAN MARU with unknown casualties. CH-9 counterattacks BAYA and drops 21 DCs .
That same afternoon, at about 1720, the convoy is attacked by LtCdr (later Cdr) William H. Hazzard's (USNA ’35) USS BLENNY (SS-324). Hazzard torpedoes and sinks small oilers NANSHIN MARU No. 21 carrying 140 tons oil products with the loss of 14 crewmen, and HOSEN MARU, loaded with gasoline with the loss of 170 passengers, eight Gunners and 18 crewmen.
21 March 1945:
Off Nha Trang, Indochina. At about 1120, convoy HI-88-I is attacked by Fifth Air Force B-25 "Mitchell" medium-bombers of the 345th Bomb Group that sink CH-33, cargo vessels MOTOYAMA MARU No. 1 and FUSHIMI MARU No. 2. MOTOYAMA MARU No. 1, also sometimes called GENZAN MARU No. 1 sinks with the loss of four crewmen; FUSHIMI MARU No. 2 carrying an estimated 1200 tons of petroleum sinks with three crewmen and 11 others KIA. The B-25's also damage CH-9, small oiler TAKASAGO MARU NO. 6 and cable-layer TATEISHI. Damaged CH-9 and CH-20 take refuge at Nha Trang.
One B-25 is lost. Four crewmembers are captured. One dies of injuries. Later, the Japanese decapitate the other three crewmen.
At 1120 ,USN codebreakers intercept and decrypt a message from CH-33 that reads: “Engaging 15 B-25s. CH-33 and No. 2 FUSHIMI MARU sank.”
Codebreakers decrypt another message that reads: “At 1100 in position 12-03N, 109-00E convoy HI-88I
. . .” CH-33 sunk and “CH-9 is to ---anchor off Natoran at 1200----. Killed in battle: Captain and 7 others. Wounded: 222 men.” A later Japanese report amends the location of this attack to 12-30.7N., 109-14.3E.
10 May 1945:
Removed from the Navy List.
 Some sources show GYOKUYO MARU as OYO MARU.
Thanks go to John Whitman of the USA for info on CNO intercepts of Japanese messages and to Mr. Gilbert Casse of France for general assistance.
-Bob Hackett, Sander Kingsepp and Peter Cundall.
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