OPERATIONAL HISTORY OF THE I-400 CLASS

Since 06-26-05

From TOM PAINE'S JOURNAL: JULY 1945 TO JANUARY 1946

Several surviving Japanese submariners have described the hopes that accompanied the completion of the top secret boats in late 1944. As they became available the four giant submarines were assigned to a newly-created SubRon One, a ten-bomber strike force:

Submarine Squadron One, Captain Tatsunosuke Ariizumi, I.J.N.;

H.I.J.M.S. I-13, Commander Ohashi, I.J.N. - 2 aircraft;
H.I.J.M.S. I-14, Commander Tsuruzo Shimizu, I.J.N. - 2 aircraft;
H.I.J.M.S. I-400, Commander Toshio Kusaka, I.J.N. - 3 aircraft; and
H.I.J.M.S. I-401, Commander Shinsei Nambu, I.J.N. - 3 aircraft.

For their first mission Vice Admiral Jisaburo Ozawa, Vice Chief of the Navy General Staff, selected Operation PX, a top secret plan to use SubRon One's ten aircraft to unleash bacteriological warfare on populous areas of the American west coast and Pacific Islands. Infected rats and insects would be dispersed to spread bubonic plague, cholera, dengue fever, typhus and other plagues. General Ishii's infamous medical laboratory at Harbin, Manchuria, had developed the virulent germ warfare agents and confirmed their lethality by infecting helpless Chinese and Caucasian prisoners.

On March 26th, 1945, this sinister mission was canceled by General Yoshijiro Umezu, Chief of the Army General Staff, who declared that "Germ warfare against the United States would escalate to war against all humanity." As an alternative the staff considered bombing San Francisco, Panama, Washington or New York, and decided to launch a surprise air strike against the Panama Canal's Gatun Locks. Destroying these locks would empty Gatun Lake and block the passage of shipping for months.

For the 17,000 mile round trip to Panama each submarine needed 1600 tons of diesel fuel, which was unavailable at Kure. I-401 was therefore dispatched to Dairen, Manchuria, to bring back the needed oil. On April 12th she grazed a B-29 laid mine off Hime Shima Lighthouse in the Inland Sea and had to return for repairs. In her place I-400 successfully carried out the undersea tanker mission.

By early June all four boats were fueled, armed, equipped with new snorkels, and disguised with false funnels. They sailed north through Tsushima Strait and the Sea of Japan to Nanao Bay on the west coast of Honshu near Takaoka. Training there was hampered by B-29 laid mines, American submarines penetrating their training areas, and shortages of aviation gasoline, material and aircraft, but SubRon One managed to launch a number of simulated air strikes on a full scale model of the Gatun Locks erected at Toyama Bay.

While the submersible carriers were perfecting their tactics to cripple the Panama Canal, the position of the Japanese Navy was steadily deteriorating. Before the submarines could set sail for Panama more than 3000 Allied warships and transports had reached the Pacific for Operation Olympic, the forthcoming invasion of Japan. This growing threat forced Tokyo strategists to reconsider the attack on distant Panama, which now appeared a questionable diversion. Over his vehement objections Captain Ariizumi was ordered to abandon his squadron's carefully rehearsed canal strike and attack instead American naval forces at Ulithi Atoll. In his account of this period Captain Orita relates how Sixth Fleet staff in Tokyo told the fulminating ComSubRon One: A man does not worry about a fire he sees on the horizon when other flames are licking at his kimono sleeve!

In response to the new orders I-13 proceeded on July 4th to the Ominato Naval Base on the northern tip of Honshu. There she loaded two crated C6N2 Nakajima Ayagumo (Colored Cloud) long range reconnaissance aircraft, then sailed into the Pacific through Tsugaru Strait bound for Japan's island stronghold of Truk. After repairing a hot propeller bearing I-14 followed on July 14th. On the 23rd I-400 and I-401 departed Ominato on separate tracks far to the east for a rendezvous at sea southeast of Ulithi in three weeks.

I-13 was probably sunk east of Honshu on the 16th by the destroyer escort Lawrence C. Taylor (DE-415) and planes from the escort carrier U.S.S. Anzio (CVE-57).

The location of a heavy storm encountered by I-401 and an electrical fire that threatened I-400 are also marked. On August 4th I-14 docked at Truk and unloaded her two Ayagumo aircraft, whose 2400 mile range made possible scouting flights to Ulithi (lower left) in preparation for the air strike by I-400 and I-401 scheduled for August 17th. In the meantime Sixth Fleet Headquarters in Tokyo was positioning Kaiten-carrying submarines off Ulithi for simultaneous suicide torpedo attacks.

Bypassed Truk had become a live practice bombing range for the U.S. Army Air Force, used to train new B-29s aircrews flying from Guam. Constant hammering had destroyed all the long range reconnaissance aircraft there, but a few attack planes were operational. I speak from personal knowledge, having been Officer of the Deck of the U.S.S. Pompon (SS-267) on lifeguard station off Truk at dawn on July 5th when a circling plane we thought friendly suddenly dove at us. As the pilot banked I spotted orange "meat balls" on her wings, and instantly pulled the plug. Down we plunged past 150 feet, the general alarm bonging insistently as I called out over the intercom: Rig for Depth Charge! Rig for Depth Charge! For some reason he didn't drop, so we thankfully secured and piped all hands to breakfast. Over beans and bacon the skipper drily repeated his favorite maxim: Don't worry, Tom -- there's not a Jap within a hundred miles!

Suddenly, on August 15th, Emperor Hirohito broadcast direct from the Imperial Palace his dramatic decree ending hostilities. The I-boat crews off Ulithi were thunderstruck; their combat careers ended just as they reached the attack rendezvous. After a council of war with his officers, the shattered ComSubRon One reluctantly carried out Tokyo's orders to cease hostilities, hoist a black flag, and return on the surface to his home port. Captain Ariizumi ordered his squadron to jettison all documents and munitions, fire all torpedoes, and catapult all aircraft into the sea. Admiral Lockwood tells how the huge I-Boats were intercepted east of Honshu on August 28th and taken over by the U.S. Navy.

When the unusual boats were brought alongside the submarine tender U.S.S. Proteus (AS-19) off Yokosuka Commander William B. "Barney" Sieglaff was named skipper of the I-400 prize crew, Hi Cassedy was given I-401, and I-14 was given to Commander John S. "Junior" McCain, son of the carrier task force commander Vice Admiral John S. "Slew" McCain (and father of Arizona Senator John S. McCain, III).

As skipper of the submarine Searaven (SS-196) Hi Cassedy had rescued 31 RAAF personnel from Timor in a bold two-night operation in 1942, and three years later in command of Tigrone (SS-419) plucked a record 31 U.S. airmen from the sea off Honshu. He didn't last long in command of I-401, though, running afoul of Admiral Halsey in a misunderstanding over confiscated Japanese swords. Hi thus became the only U.S. naval officer to be relieved of command of a Japanese submarine. I remember him for another first, though: when he died his ashes were placed in a canvas-covered box and fired from a torpedo tube in deep water -- a unique submarine Viking's funeral.

I-14's new skipper, "Junior" McCain, had commanded the U.S.S. Gunnel (SS-253) with distinction from landings in North Africa to Pacific war patrols. In the late 1960s I worked with him again when I headed NASA and he was Commander Pacific, providing carrier support for the splashdown of Apollo Astronauts returning from the moon. While he smoked his famous long, black, cigars we chuckled over the irony of two old I-boat sailors working together on interplanetary transport! His wife was a charming identical twin, whom he liked to scandalize by answering queries on how he told them apart by saying "I don't - that's their problem." He was an outstanding naval officer.

I-400's first American skipper, Barney Sieglaff, was highly regarded for his outstanding war patrols in the U.S.S. Tautog (SS-199). As the duty officer of her relief crew during the Pearl Harbor attack he'd helped lug a 50 caliber machine gun to the bridge and shoot down a bomber flying low over the Sub Base to attack Battleship Row; he was thus the first submariner to strike back at the enemy. A year later he took command of Tautog in Fremantle, and in seven aggressive war patrols sank 13 enemy vessels totalling 33,000 tons. These included the torpedoed destroyers H.I.J.M.S. Isonami and Shirakumo, and, in a minefield he laid off the oil port of Balikpapan, H.I.J.M.S. Amagiri, the destroyer which sank Lieutenant John F. Kennedy's PT-109. Because he planned the 1945 submarine foray under the Tsushima Strait minefields into the Sea of Japan it was named Operation Barney. 12 To me his taking command of I-400 alongside Proteus brought the submarine war full circle, from Pearl Harbor to Tokyo Bay.