Operation Storm: Japan's Top Secret Submarines and Its Plan to Change the Course of World War II (31 page)

The
I-401
departed Kure on April 11.
³⁷
She had just left the harbor when a swift current ran her aground. Nambu dumped ballast and quickly refloated her,
³⁸
but it was an unlucky start. The next day the
I-401
was again traveling on the surface. It was 8:50 in the morning, and they were off Hime Island in the Inland Sea. Nambu was on the bridge, and since they had only a short distance to go before reaching the entrance to Shimonoseki, he made it a point to warn his sonar operator to keep a sharp lookout.
³⁹

Both Ariizumi and Yata, the chief gunnery officer, were in the wardroom having coffee.
⁴⁰
A moment later both men felt an explosion lift the sub’s stern into the air. Ariizumi’s coffee cup hit the ceiling before spilling its contents.
⁴¹
Moments later the crew began sealing the sub’s watertight doors.

In the split second it took Nambu to register the explosion, he knew they’d hit a mine. Was it survivable? Until the damage reports came in, he was at the mercy of his imagination. In the meantime, the sound of water gushing into the sub was not reassuring.
⁴²

T
HE
I-401
WAS IN
160
FEET OF WATER WHEN A MAGNETIC MINE
released its anchor and floated toward the surface.
¹
The ensuing explosion may have shaken the whole boat, but it was the stern that bore the brunt of the damage.

A white haze enveloped the aft deck as a churning mass of ocean boiled around the stern.
²
Had the
I-401
been traveling any slower, the mine would have hit amidships, possibly sinking her. As it was, the
I-401
’s twin propellers and their respective shafts were also vulnerable, as were her stern planes. A mine explosion in the stern could just as easily sink them.

Initial reports indicated that a fuel tank had been ruptured,
³
and a Kingston valve (which regulated the flow of seawater into the ballast tanks) was damaged.
⁴
It didn’t take long for Nambu to ascertain the
I-401
would survive. Even so, she was in no condition to travel to China. Traveling with an oil leak was like laying down breadcrumbs for the enemy to follow. As for the gushing water, the explosion had ruptured a sake tub, sending its contents spouting into the sub.
⁵
Everyone had a good laugh about that.
⁶
It had been a close call though. All they could do now was limp back to Kure.

Unfortunately, Ariizumi was no closer to obtaining the fuel he required. With his flagship in need of repair, he had no choice. He had to send the
I-400
in place of her. Kusaka’s sub was virtually identical to the
I-401
, save for a few cosmetic differences. She also had the same large fuel capacity, which meant she was a more logical choice than the smaller-capacity
I-13
or
I-14
. The one thing the
I-400
did have that the other subs in the
Sen-toku
fleet lacked was Cdr. Toshio Kusaka.

Kusaka was a highly skilled captain, as evidenced by his commander title and three previous sub commands.
⁷
He’d also recovered enough from the minor wounds he’d sustained during the Kure air raid to resume skippering his sub. Born in a small village on the island of Shikoku in June 1904, Kusaka had wanted to be a fighter pilot but was steered toward submarines because of his small stature.
⁸
Like Nambu, he was an Etajima graduate. He had also been at Pearl Harbor, captaining the
I-74
. When Doolittle’s Raiders bombed Tokyo in April 1942, it was Kusaka’s sub that had been sent to intercept the USS
Hornet
(CV-8).

It’s likely Kusaka and Nambu knew each other before joining the
Sen-toku
squadron. Kusaka had turned command of the
I-74
(later designated the
I-174
) over to Nambu in November 1942. Kusaka had also captained war patrols off the Australian coast and transported ammunition and supplies, just like Nambu. Although their résumés were similar, Kusaka was more experienced than Nambu, which is probably why he had his own command while Nambu had to captain under Ariizumi’s watchful eye.

Kusaka had also served in the Indian Ocean at roughly the same time as Ariizumi. He’d commanded the
I-26
and sunk two tankers between December 1943 and March 1944. One of his most memorable missions involved landing Indian revolutionaries near Karachi to promote an uprising against the British. Though most of the nationalists were captured or killed, it was the kind of old-fashioned spy caper that only happened in novels.

Three days after Ariizumi massacred the SS
Tjisalak
’s crew, Kusaka followed suit, using the
I-26
’s deck guns to riddle the lifeboats of an American Liberty ship, the SS
Richard Hovey
.
⁹
Kusaka killed eight survivors,
^*
making him one of four SubRon 8 sub captains implicated in killing prisoners. By August 1944, Kusaka was named chief equipment officer for the
I-400
.

“Kusaka was the best captain anyone could ask for,” Lt. Kazuo Nishijima, the
I-400
’s chief navigator, noted.
¹⁰
Since Nishijima was the sub’s second seniormost officer after Kusaka, it was no small compliment.

Kusaka’s many years of combat experience, combined with his unquestionable ability and good judgment, earned him the respect of his crew.
¹¹
Importantly, he radiated the same kind of confidence as the
Segundo
’s Captain Fulp. Not surprisingly, Kusaka’s crew would do anything for him.
¹²

Dalian, located near Port Arthur on the Yellow Sea, was an important commercial port. When Russia lost its war with Japan, it had conceded Dalian in 1905. Since then, the IJN had made significant investments in the port, which was now home to a large stock of diesel fuel.

The
I-400
left Kure for Dalian on April 14 disguised as a frigate.
¹³
Barrels were placed on the catapult rails and covered with a canvas tarp, while dummy cannons and machine guns were added to complete the ruse.
¹⁴
Kusaka navigated the Inland Sea at reduced speed to avoid triggering mines. As he approached Himejima, the island where the
I-401
had nearly been lost, he encountered some good luck. Two Japanese merchant ships were also heading through the Shimonoseki Strait. Kusaka joined the middle of their single-file procession, using the lead vessel to shield his sub from any mines in his path.

As Kusaka followed the first ship into the narrow strait, the
I-400
proceeded slowly on the surface. The channel was quiet save for the seagulls overhead, whose shrill cries sounded like a warning not to proceed. From his position on the bridge, Kusaka could see the red-bellied bottoms of capsized ships as the
I-400
passed by. Those that had rolled over revealed the ugly puncture wound of a mine explosion against their hull. Other ships had simply settled on the canal floor, their bottoms ripped out by 1,200 pounds of high explosives. With their decks awash, and masts poking above the waves, Shimonoseki looked like a graveyard for ships.

Suddenly, the freighter ahead erupted in an explosion as a
mine tore out its keel.
^†
The ship was so close that the smoke pouring from her hold made Kusaka’s eyes water. Though he could see the ship’s crew jumping overboard, he could not stop to assist them. Everyone was on their own in a situation like this. The shore was not far away, and rescue stations had been established for just such an occasion. The explosion had been so violent though that many of the ship’s crew probably never made it above deck. It was a chilling reminder that the odds of survival were no more than a coin toss.

After Kusaka navigated past the expiring vessel, he found himself in the lead. Without a buffer, he worried the
I-400
would be sunk next. As anyone who’s ever been trapped in a minefield knows, the anticipation of destruction is excruciating. Lookouts can scan the water all day, but they are unlikely to spot a mine beneath the waves. What’s more, sonar was useless in a narrow channel riddled with wrecks. Even so, Kusaka never considered turning back. The channel was too narrow, there was a ship following him, and Ariizumi would have condemned him. His only escape was forward.

To Kusaka’s surprise the ship behind him was next to hit a mine.
¹⁵
After an enormous explosion, the freighter quickly filled with water. Kusaka must have felt that the spirit Ise watched over him that day, since the
I-400
was the sole survivor of a three-ship convoy.

After successfully navigating the rest of the strait, the
I-400
arrived in Dalian on April 20.
¹⁶
Kusaka released his crew for shore leave, which included a Chinese banquet hosted by the Manchurian Railway, and the company of “comfort women” from Korea, China, and Japan.
¹⁷
In the meantime, the
I-400
took on 1,700 tons of fuel made from liquefied coal
¹⁸
as well as a cargo of soybeans,
¹⁹
iron,
²⁰
peanuts,
²¹
and molybdenum.
²²
When Kusaka departed for Kure, the return trip proved uneventful.
²³

W
HILE THE
I-401
was undergoing repair, Ariizumi used the time to adopt what he hoped would be a game-changing technology. The device he wanted to use was called a snorkel, and the reason he wanted his flagship to have one was that he believed it would help her to remain hidden underwater longer.

The device was simple enough. Two pipes, one for air intake, the other for exhaust, were mounted on the periscope shears. Both pipes connected to the sub’s auxiliary engines, supplying oxygen and venting toxic gas. When the sub was at periscope depth, it could hydraulically raise its snorkel above the surface,
²⁴
and because each pipe had a self-sealing valve, water couldn’t flood in.

The small size of the pipes made them invisible to radar and difficult to spot at a distance. Radar itself was a game-changing innovation that put Sixth Fleet subs at a disadvantage. Since Japan adopted the technology late, Ariizumi was betting the snorkel could help level the playing field. Being able to use their auxiliary engines while submerged might give them just enough extra time to escape undetected.

Ariizumi’s hopes for the snorkel were not unreasonable. If the
Sen-toku
subs could remain hidden underwater a little bit longer, they could slip past the U.S. Navy to launch a surprise attack.
²⁵
Interestingly, American subs didn’t use snorkels. The U.S. Navy felt their cost, weight, space requirement, and reduction in engine performance outweighed any benefits.
²⁶
It didn’t hurt that the Pacific sub force was so strong, it had little reason to hide. U.S. subs wouldn’t adopt the technology until after the war. When they did, Portsmouth was the first shipyard to add them.
²⁷

After the
I-400
returned to Kure, Ariizumi ordered his three other submarines outfitted with snorkels, making them one of the first Sixth Fleet subs thus equipped.
²⁸
Installation took most of May,
²⁹
but the lost time was worth it, especially if it created an advantage Ariizumi could exploit.

Next, the squadron commander called a meeting to brief the
officers of SubRon 1 and the 631st air group on the Panama Canal attack. Held at Kure Naval Base on or about April 25,
³⁰
the meeting included among others: the 631st’s seniormost officer, Lt. Cdr. Masayoshi Fukunaga; two of its most senior pilots, Asamura and Takahashi; and SubRon 1’s four sub captains: Nambu, Kusaka, Shimizu, and Ohashi. Given the importance of the mission, representatives from the Naval General Staff and Sixth Fleet also attended, including Commanders Shojiro Iura and Yasuo Fujimori.
³¹

The meeting began promptly at 9:00
A.M
.
³²
Chairs had been set up in the briefing room, and a large board diagrammed the route to Panama.
³³
Ariizumi arrived, looking tan from all the time he’d spent on the
I-401
’s bridge. When all relevant personnel had gathered, the 631st’s XO, Fukunaga, called the meeting to order.

“Based on the latest map exercise,” he said, “I would like to explain SubRon 1’s strategic plan and decide our training goals going forward.”
³⁴

The plan was as easy to articulate as it was difficult to carry out. First, the
Sen-toku
squadron, comprising the
I-400, I-401, I-13
, and
I-14
, would travel the same course as Nagumo’s carriers had on their way to Pearl Harbor.
³⁵
After passing north of Hawaii, Ariizumi’s subs would then head southeast until they reached the coast of Ecuador.
^‡
When they were 100 miles off Ecuador, the subs (separated by 50 miles) would surface and launch their ten
Seiran
aircraft at 3:00
A.M
.
³⁶
To accommodate the maximum bomb load, the
Seiran
would be stripped of their floats. Once launched, the aircraft would rendezvous, then fly northeast across the top of South America, passing over Colombia. To avoid radar contact, they would fly at low altitude. Once they reached the Caribbean, they would double back and head toward the Atlantic entrance to the canal.