© 2006-2009 Bob Hackett and Sander Kingsepp


Midget Submarines in the Marianas

17-18 February 1944: American Operation "Hailstone" - The Attack on Truk:
Caroline Islands. Vice Admiral (later Admiral) Marc A. Mitscher’s 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. Beginning at dawn, strikes are launched about every hour for two days.

During the raids, TF 58 sinks 31 merchant transports and 10 naval vessels (two light 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.

Truk Atoll, Caroline Islands

February 1944:
After the attack on Truk, the IJN decides to establish a midget submarine base on Eten (Takeshima) Island, Truk as protection against any pending American landing. In the event, no midget submarines are ever stationed at Truk, but their technical crews, cranes and other equipment are delivered there by various unidentifed ships.

20 February 1944:
Five Type C midget submarines are transferred from Ourazaki (Base P) at Kurahashi Jima to Yokosuka and depart for Truk in two batches.

May 1944:
Detachment "A" (Ko) consisting of three midget submarines under Lt ( j.g.) Sato Masayoshi is transported to Truk via Guam by unidentified ships at an unknown time. In May, they arrive at Saipan.

Southern Marianas
(U.S. Marine Corps)

19 May 1944:
Detachment "B" (Otsu) consisting of two midget submarines under Lt ( j.g.) Fukasa Yasuzo departs Yokosuka for Saipan towed by HORAISAN and SHOKEN MARUs in convoy No. 5319 (or 3519) escorted by kaibokan CD-16.

29 May 1944:
Marianas. Early in the morning, the convoy is spotted by lookouts aboard LtCdr (later Rear Admiral) John S. Coye's USS SILVERSIDES (SS-236). Coye fires three bow torpedoes at each ship and sinks both HORAISAN and SHOKEN MARUs. Both of Lt ( j.g.) Fukasa's Detachment B's two midget submarines, twelve Type 97 torpedoes and three crewmen are lost.

12 June 1944: American Operation “Forager” – The Invasion of Saipan, Marianas:
Vice Admiral (later Admiral) Richmond K. Turner’s Task Force 52 lands Marine LtGen Holland M. Smith’s V Amphibious Corps and the invasion of Saipan begins. Communications between Vice Admiral (Admiral, posthumously) Takagi Takeo’s (former CO of MUTSU), Advance Expeditionary Force (Sixth Fleet) are disrupted by the invasion. Command of the Sixth Fleet’s submarines passes to Rear Admiral Owada Noboru (former CO of YAMASHIRO), ComSubRon 7 at Truk.

ENTERPRISE (CV-6) off Saipan
(Naval Historical Center)

12 June - 8 July 1944:
Saipan, Marianas. After the American landing, the crews of Lt ( j.g.) Sato's Detachment A's three midget submarines destroy their vessels and join the Sixth Fleet's staff. Later, they die to the last man, probably fighting as infantrymen.

August 1944:
Guam, Marianas. A Type "C" midget submarine is discovered in shallow waters off Togcha beach near Talofofo, Guam. The two crew members surrender three days later. [1]

November 1944:
Guam. The crew of Captain J. P. Thew's submarine tender USS SPERRY (AS-12) constructs a rest camp on Guam for submariners and support personnel. The area is named "Camp Dealey" in honor of Cdr (MOH, posthumously) Samuel D. Dealey, CO of USS HARDER (SS-257), KIA in Aug '44 with his 78-man crew.

Guam. The midget submarine discovered in Aug '44 is placed on display at Camp Dealey. [2]

HA-51 at Guam in 1945
(U.S. Naval Historical Center)

The submarine is moved to U.S. Naval Base Guam.

February 1999:
Midget submarine “HA-51” is listed in the National Register.

1 October 2001 - 30 September 2002:
During FY02, HA-51 is completely restored for COMNAVMARIANAS under a $247,000 contract. This is likely the last Type C midget submarine in existence.

1 April 2008:
The U.S. Naval Forces Marianas transfers possession of HA-51 to the National Park Service's T. Stell Newman Visitor’s Center outside the main gate of U.S. Naval Base Guam.

Restored HA-51

Authors' Note:

[1] This may be one of Lt ( j.g.) Fukasa's Detachment B's two midget submarines. When its towing vessel sank, the craft probably broke loose and started to drift.

[2] The number "51" was painted on the midget submarine's conning tower indicating that it may be HA-51; however, some Japanese sources doubt this identification. The hull was severed behind the conning tower with a short gap between the forward and after sections.

-Bob Hackett and Sander Kingsepp

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