KUSENTEI!

© 2005-2009 Bob Hackett, Sander Kingsepp and Peter Cundall

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1942:
Innoshima. Laid down at the Hitachi Zosen K.K. shipyard.

1942:
Launched and numbered CH-40.

31 March 1943:
Completed and assigned to the Yokosuka Guard Force. Patrols the Ise, Aomori, Iwate, and Miyagi areas and escorts convoys.

5 September 1943:
Reassigned to SubChasDiv 23 of the 8th Base Force in Vice Admiral, the Baron, Samejima Tomoshige's (37)(former CO of NAGATO) 8th fleet at Rabaul. Escorts convoys between Rabaul, Palau and Truk.

14 October 1943:
CH-40 and CH-17 depart Palau escorting convoy N-406 consisting of ASUKA, RYUOSAN, TAGA, FUKKO, TAIRIN and HOKKAI MARUs.

18 October 1943:
At 0345, TAIRIN MARU is torpedoed and sunk by LtCdr (later Rear Admiral) John S. Coye's USS SILVERSIDES (SS-236) at 00-22N 143-23.

21 October 1943:
The remainder of the convoy arrives at Palau.

23 November 1943:
At 1400, CH-40 departs Truk escorting convoy No. 5233 consisting of NIPPO and CHOKO MARUs and NANKAI MARU No.2 (the latter towing "special" craft No. 35). The convoy later arrives at Kwajalein on 1 December. [1]

26 November 1943:
CH-40 departs Rabaul for Truk escorting a convoy consisting of ONOE and KAMOI MARUs and HOSHI MARU No. 5.

275 miles NW of Kavieng, New Ireland. At 2116, LtCdr James W. Davis' torpedoes and sinks ammunition ship ONOE MARU at 00-40N 148-20E. CH-40 counterattacks, but is damaged by the explosion of her own depth charges. Four subsequent attempts by RATON to sink the remaining freighters are defeated by the escorts’ effective countermeasures.

27 November 1943:
At 0605, USN codebreakers intercept a message from CH-40 that reads: “Picked up captain and 195 members of the crew of ONOE MARU which sank at 2240. Headed for Truk at 0020 but could not use radio because of damage sustained while making depth charge attack.”

1 December 1943:
At 0700, CH-40, CH-16, CH-20 and CH-29 depart Truk escorting convoy 1013 consisting of submarine tender NAGOYA MARU, transport YAMAKUNI MARU (ex YAMAKAZE MARU) and aircraft transport KEIYO MARU.

5 December 1943:
At 1510, arrives at Rabaul.

17 January 1944:
CH-40 and CH-16 depart Rabaul in convoy O-604 consisting of TAIAN, FRANCE and SHOUN MARUs.

23 January 1944:
At 1345, the convoy arrives at Palau.

28 January 1944:
At 1600, CH-40, CH-16, CH-34, CH-35 and auxiliary submarine chasers CHa-47 and CHa-61 depart Palau escorting convoy SO-805 consisting of TOEI and HOKKAI MARUs, oiler TAKATORI MARU No. 2, TAIEI and TOKO MARUs. The convoy is also given air cover.

30 January 1944:
At 0150, IJA freighter TOKO MARU, carrying troops of the 31st Infantry Regiment and 4th Field Hospital to Manus Island in the Admiralties, is torpedoed by LtCdr (later Captain) Slade D. Cutter's USS SEAHORSE (SS-304) at 06-20N, 138-08E. TOKO MARU sinks by the stern taking down 457 troops.

1 February 1944:
IJN transport TOEI MARU, carrying drummed gasoline and ammunition, is sunk by SEAHORSE's last torpedoes at 04-24N, 143-15E. LtCdr Cutter makes for Pearl Harbor.

E 4 February 1944:
CH-40 arrives Rabaul.

18 February 1944:
CH-40 and CH-22 depart Rabaul for Moji escorting convoy O-902 consisting of SHINTO MARU No. 1 and TATSUKIKU MARU.

19 February 1944:
22 miles N of Kavieng, New Ireland, near Kaut Bay. At about 1430, Fifth Air Force B-25s of the 345th Bomb Group's 500th and 501st Squadrons, A-20 "Havoc" light bombers of the 3rd Bomb Group and P-38 "Lightning" fighters attack and destroy convoy O-902. They sink CH-40 and CH-22 at 03-04S, 150-42E and cargo ships SHINTO MARU No. 1 and SHINKIKU MARU at 02-46N, 150-42E. SHINTO MARU No. 1 was evacuating hundreds of ground personnel of the IJN 11th Air Fleet from Rabaul to Truk.

The USAAF's Fifth Air Force wipes out the entire convoy.

31 March 1944:
Removed from the Navy List.

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Authors' Notes:
[1] CH-40 apparently was detached from convoy No. 5233 and made port at Rabaul on or before 26 November.

Thanks go to John Whitman for info on CH-40's intercepted message.

-Bob Hackett, Sander Kingsepp and Peter Cundall.

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