IJN Submarine I-55: Tabular Record of Movement

2001-2013 Bob Hackett & Sander Kingsepp
Revision 2

15 June 1942:
Laid down at Kure Navy Yard as Submarine No. 628.

1 November 1942:
Designated I-55. Provisionally attached to Kure Naval District.

20 April 43:

5 March 1944:
LtCdr Izutsu Monshiro (57)(former CO of I-6) is appointed the Chief Equipping Officer.

20 April 1944:
Completed, commissioned in the IJN and based in the Kure Naval District. I-55 is assigned to Rear Admiral Ishizaki Noboru's (former CO of HYUGA) SubRon 11 in Vice Admiral (Admiral, posthumously) Takagi Takeo's (former CO of MUTSU) Sixth Fleet (Submarines). LtCdr Izutsu Monshiro (former CO of I-6) is the Commanding Officer.

13 June 1944: Operation "A-GO" - The Defense of the Marianas:
Admiral Toyoda Soemu (former CO of HYUGA), CINC, Combined Fleet, activates Operation A-Go.

15 June 1944: American Operation "FORAGER" - The Invasion of Saipan:
Vice Admiral (later Admiral) Richmond K. Turner's Task Force 52 lands Marine LtGen Holland M. Smith's V Amphibious Corps and the invasion begins.

Late June 1944:
I-55 is scheduled to undergo conversion to carry Special Weapon No. 8 (a navalized version of the Fu-Go "balloon bomb"). The intended conversion includes adding the hydrogene equipment and the balloon-launching equipment. None of these are actually embarked.

30 June 1944:
Departs Kure for Yokosuka.

1 July 1944:
Arrives at Yokosuka.

6 July 1944:
Departs Yokosuka for Guam, towing an "unpoto" gun container.

8 July 1944: American Operation "STEVEDORE" - The Invasion of Guam:
Rear Admiral (later Vice Admiral) C. Turner Joy's Task Group 53.18 begins weeks of daily bombardment of Guam by cruisers and destroyers and later battleships and carrier-based air strikes.

10 July 1944:
Reassigned to SubDiv 15, Advance Force.

13 July 1944:
I-55 is ordered to abandon the Guam supply mission and rescue the staff of the 1st Air Fleet stranded on Tinian. LtCdr Izutsu casts off the unpoto.

13 July 1944:
At 0040 (JST), I-55 signals the Sixth Fleet that her estimated time of arrival at Tinian is 15 July. 78 miles off Rorogattan Point, Saipan. At 2120, an American patrol plane spots a submarine submerging. Its position is relayed to a hunter-killer group of USS GILMER (APD-11) and USS WILLIAM C. MILLER (DE-259) screening the invasion transports. GILMER and MILLER are detached to track the submarine.

14 July 1944:
At 0022, the hunter-killer group arrives at the submarine's last reported position and commences searching. Seven hours later, LtCdr D. F. Francis' USS MILLER gets a sound contact at 1,700 yards. Francis approaches the contact at 15 knots. At 0726, he opens his attack with a pattern of 13 depth charges. At 0752, Francis drops a second pattern of 13 charges.

At 0804, MILLER's crew sees pieces of wood coming to the surface about 500 yards ahead on the starboard bow. At 0805, MILLER's crew hears a heavy underwater explosion that shakes the ship. Then the crew sees a large "boil" in the water. At 0806, LtCdr Francis lays a third 13-charge salvo that finishes the submarine - probably I-55. MILLER closes the oil slick and debris and recovers pieces of cork insulating material, splintered wooden decking and a seaman's cap at 15-18N, 144-26E. [1]

15 July 1944:
Presumed lost with all 112 hands off Tinian.

10 October 1944:
Removed from the Navy List.

Authors' Note:
[1] Some sources claim the submarine sunk at this time and place was RO-48.

Thanks go to Dr. Higuchi Tatsuhiro of Japan.

Bob Hackett and Sander Kingsepp.

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