SENSUIKAN!

© 2001-2016 Bob Hackett & Sander Kingsepp
Revision 2

27 April 1942:
Laid down at Sasebo Navy Yard as Submarine No. 373.

25 September 1942:
Designated I-43 and provisionally attached to Yokosuka Naval District.

25 October 1942:
Launched.

15 August 1943:
Cdr (Captain, posthumously) Endo Shinobu (52)(former CO of I-30, current instructor at Otake Submarine School) is appointed the Chief Equipping Officer of I-43 as an additional duty. [1]

25 October 1943:
Attached to Yokosuka Naval District.

5 November 1943:
I-43 is completed and assigned to SubRon 11. Cdr Endo Shinobu is the CO.

Following her working-up, I-43 is converted to carry a 46-foot waterproof Daihatsu-type landing barge mounted abaft the conning tower. Her 5.5-inch aft deck gun is landed.

15 November 1943:
I-43 is assigned to the Sixth Fleet's SubRon 11 with I-42, I-45, I-52, I-183, I-184, RO-40, RO-41, RO-43, RO-113, RO-114 and RO-115.

December 1943:
I-43 departs Sasebo for Yokosuka.

January 1944:
I-43 departs Yokosuka for Kure.

9 February 1944:
I-43 departs Kure on a special mission via Saipan to Truk.

11 February 1944:
I-43 is reassigned to SubDiv 15, Sixth Fleet.

13 February 1944:
Arrives at Saipan.

14 February 1944:
Vice Admiral (Admiral, posthumously) Takagi Takeo's (former CO of MUTSU) Sixth Fleet Headquarters signals I-43 to proceed to Truk. I-43 departs Saipan carrying 59 sailors from the 2nd Platoon of the 101st Sasebo Special Naval Landing Force aboard. Her estimated time of arrival at Truk is 16 February.

15 February 1944:
280 miles ESE of Guam. LtCdr William A. Stevenson's USS ASPRO (SS-309) is submerged on station as part of the forthcoming Operation "Hailstone". At 1106 his soundman picks up I-43's propeller noises. At 1121, Stevenson sights a surfaced "I-9" class submarine heading 155 (T) and zigzagging at 17 knots. She carries a numeral marking identified as 443 and a Hinomaru flag painted on the conning tower. Stevenson also observes a "large structure, possibly midget submarine" aft of the conning tower.

ASPRO is unable to close for an attack while submerged. He lets the I-boat pass, then surfaces in the daylight at 1207 and begins tracking her at flank speed.

After a long radar-assisted chase, ASPRO is able to gain a position ahead of the target. At 2223, Stevenson fires four Mk. XIV-3A torpedoes at a range of 2,100 yards. One minute later two hit I-43; she explodes and sinks by the stern at 10-23N, 150-23E. Several explosions follow until 2227.

17-18 February 1944: American Operation "Hailstone" - The Attack on Truk:
Task Force 58's five fleet carriers and four light carriers, supported by six battleships, ten cruisers and 28 destroyers, launch air attacks on Japanese ships in the lagoon, airfields and shore installations. They sink 31 transports and 10 naval vessels (two cruisers, four destroyers and four auxiliary vessels), destroy nearly 200 aircraft and damage severely about 100 more.

8 April 1944:
I-43 is presumed lost in the Truk area with all 166 hands. [2]

30 April 1944:
Removed from the Navy List.

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Authors' Notes:
[1] On 5 August 1942, Cdr Endo docked his I-30 at Lorient, France to become the first Japanese submarine CO to reach Europe during World War II.

[2] I-43's mission was a part of the IJN buildup preceding the planned counterlanding on Green Islands, Papua New Guinea. While older sources suggest that she was carrying 99 SNLF troops, newer ones agree on the lower figure.

Thanks go to Dr. Higuchi Tatsuhiro of Japan.

– Bob Hackett and Sander Kingsepp.

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