SENSUIKAN!

© 2001 Bob Hackett & Sander Kingsepp

6 April 1937:
The I-72 is completed at Mitsubishi's Kobe Yard, commissioned in the IJN and based in the Kure Naval District.

11 November 1941:
The I-72 is in SubRon 3's SubDiv 20. LtCdr Togami Ichiro is the Commanding Officer. Departs Saeki with the I-68, -69, 70,-71 and the I-73.

20 November 1941:
Arrives at Kwajalein.

23 November 1941: Operation "Z":
Departs Kwajalein for Hawaii on her first war patrol.

2 December 1941:
The coded signal "Niitakayama nobore (Climb Mt. Niitaka) 1208" is received from the Combined Fleet. It signifies that hostilities will commence on 8 December (Japan time).*

5 December 1941:
Hawaiian Islands. The I-72 reconnoiters the Kaholi Channel between Molokai and Lanai.

6 December 1941:
LtCdr Togami signals the fleet that Lahainia anchorage is empty.

7 December 1941: The Attack on Pearl Harbor:
The I-72 is stationed at the entrance to Pearl Harbor.

19 December 1941:
150 miles S of Oahu, Hawaiian Islands. The I-72 torpedoes the 5,113 ton American merchant PRUSA that is enroute from Honolulu to Baltimore. A torpedo wrecks the PRUSA's engines and she sinks within a few minutes at 16-45N, 156-00W. Eight days later, the Coast Guard rescues 14 men in a lifeboat in the vicinity of the sinking. The Captain and ten others are picked up near Fiji after 31 days.

28 December 1941:
Returns to Kwajalein.

12 January 1942:
Departs Kwajalein on her second war patrol with the I-71 and the I-73 to relieve the I-18, -22 and the I-24 that form a picket line in the Hawaii area.

21 January 1942:
Arrives at her prescribed area.

23 January 1942:
135 miles W of Honolulu. The 7,383-ton oiler USS NECHES (AO-3) is proceeding unescorted to a refueling rendezvous with Vice Admiral Wilson Brown Jr's (later President Roosevelt's Naval Aide) Task Force 11's USS LEXINGTON (CV-2) that is steaming to conduct an air raid on Wake Island.

At 0310, LtCdr Togami fires a torpedo that hits the NECHES amidships, but fails to detonate. At 0319, a second torpedo hits the oiler starboard aft on her stern and destroys her engine room. Togami maneuvers and hits the NECHES portside with a third torpedo. The I-172 surfaces to finish the job with her deck gun. She fires three rounds at the oiler, but the NECHES' gun crew returns fire from her 5-inch and 3-inch guns. Togami submerges. At 0437, the NECHES, listing to starboard, sinks by the bow at 21-01N, 160-06W.

Without the oiler's fuel, Task Force 11 cannot execute the planned strike on Wake and is ordered back to Pearl Harbor.

16 February 1942:
The I-72 returns to Kwajalein.

18 February 1942:
Departs Kwajalein with the I-71.

20 February 1942 - Aborted Raid on Rabaul:
Task Force 11, en route to attack Rabaul, is spotted by a Kawanishi H6K "Mavis" flying boat of the Yokohama Kokutai. Since surprise is lost, the American attack is cancelled. TF 11 is attacked off Bougainville by the 4th Kokutai's naval land-based bombers, but the Japanese are beaten off with heavy losses.

After the aborted raid on Rabaul, the I-72 and the I-71 are diverted to an area E of Wake Island.

5 March 1942:
Returns to Kure for repairs.

16 March 1942:
Vice Admiral, the Marquis, Komatsu Teruhisa (former CO of CA NACHI) assumes command of the Sixth Fleet (Submarines).

20 March 1942:
SubDiv 20 is disbanded. The I-72 is reassigned to SubDiv 12.

15 April 1942:
Departs Kure.

3 May 1942:
Arrives at Yokosuka.

10 May 1942:
Departs Yokosuka.

12 May 1942:
Arrives at Kure for upkeep and repairs. LtCdr Ota Takeshi (former CO of the RO-34) is assigned as the Commanding Officer. LtCdr Togami is reassigned as the Commanding Officer of the I-3.

20 May 1942:
The I-72 is redesignated the 1-172.

7 August 1942 - 9 February 1943: American Operation "Watchtower" - The Invasion of Guadalcanal, Solomons:
Rear Admiral (later Admiral) Richmond K. Turner's Amphibious Task Force 62, covered by Vice Admiral (later Admiral) Frank J. Fletcher's Task Force 61 and Rear Admiral (later Admiral) John S. McCain's Task Force 63's land-based aircraft, lands Maj Gen (later Gen/MOH/Commandant) Alexander A. Vandegrift's 1st Marine Division on Guadalcanal opening a seven-month campaign to take the island.

22 August 1942:
Departs Kure for Truk.

28 August 1942:
Arrives at Truk.

30 August 1942:
Departs Truk on her second war patrol for a reconnaissance mission to the Guadalcanal area.

30 September 1942:
Returns to Truk. The I-172 is modified as a transport submarine. She is configured to carry a 46-foot Daihatsu landing craft, amphibious tank or other external equipment.

12 October 1942:
Departs Truk with Captain Yoshisuke Okamoto, ComSubDiv 12 of the Kure SubRon embarked, on her third patrol to support a "Type A" midget submarine attack on shipping off Lunga Point, Guadalcanal.

14 October 1942:
Diverted to proceed to an area S of San Cristobal to recharge the batteries of Type A midgets from the tender CHIYODA with the I-26.

15 October 1942:
The I-172 is diverted to take station on a picket line SE of Guadalcanal (the "A" group comprising the I-1, -2,-3, -4,-5, -7, -17, -22 and the I-31).

26 October 1942: The Battle of Santa Cruz:
Rear Admiral (later Admiral) Thomas C. Kinkaid's Task Force 16 and Rear Admiral (later Vice Admiral) George D. Murray's Task Force 17 engage Vice Admiral (Admiral, posthumously) Nagumo Chuichi's (former CO of KIRISHIMA) carrier force. The ENTERPRISE (CV-6) is damaged by planes from the carriers JUNYO and the SHOKAKU. Planes from the JUNYO, SHOKAKU and the ZUIKAKU also damage the HORNET (CV-8) that later is scuttled. The JUNYO's planes damage the battleship SOUTH DAKOTA (BB-57) and the SAN JUAN (CL-54). The PORTER (DD-356) is scuttled by the SHAW (DD-373).

Douglas SBD dive-bombers (VS 10) from the ENTERPRISE damage the carrier ZUIHO. SBD's (VB-8, VS-8) from the HORNET also damage the carrier SHOKAKU and the destroyer TERUTSUKI. Grumman TBF torpedo-bombers (VT-6) from the HORNET damage the cruiser CHIKUMA.

28 October 1942:
Group "A" is disbanded.

3 November 1942:
At 0510 (Zulu), the I-172 sends a short "enemy vessels sighted" report. This is the last signal received from the I-172.**

27 November 1942:
Presumed lost with all 91 hands off Guadalcanal. The cause of her loss remains unknown.***

Captain Okamoto is promoted Rear Admiral, posthumously and LtCdr Ota is promoted Commander, posthumously.

15 December 1942:
Removed from the Navy List.

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Authors' Notes:
*Mt. Niitaka, located in Formosa (now Taiwan), was then the highest point in the Japanese Empire.

**Official USN credit for the I-172 is given to the USS SOUTHARD (DMS 10), for a sinking on 10 November 1942 at the S end of Indispensable Strait at 10-13S, 161-09E, but Japanese records indicate that the submarine claimed by SOUTHARD was the I-15.

***On 29 October 1942, Lt F. Joe Hill's PBY-5 "Catalina" of VP-11 claims sinking a submarine - thought by some to be the 1-172 - at 13-15S, 162-45E, but the I-172's last report is made six days later. Japanese sources do not credit Hill with the I-172's sinking.

Special thanks for help in preparing this TROM go to Dr. Higuchi Tatsuhiro of Japan. – Bob Hackett and Sander Kingsepp.

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