Yata, the I-401’s chief gunnery officer, was taken to MacArthur’s SCAP headquarters and asked whether Ariizumi had really committed suicide. Yata answered truthfully. Policemen still watched his house, however, hoping the officers they were looking for would show up.12
Two of Ariizumi’s Sen-toku captains, the I-400’s Kusaka and the I-14’s Shimizu, had participated in massacres. The Sen-toku crews knew this, so they had something to hide. Since neither Nambu nor Yata had served in the Indian Ocean, they were eventually cleared. Kusaka, however, didn’t have it so easy. The day after the surrender ceremony, American interrogators descended upon his sub and began calling officers into the wardroom one by one.
An American translator encouraged Takahashi to tell them everything, promising, “We won’t treat you badly.”
Takahashi was hardly going to spill the beans, since he’d massacred prisoners himself. He chose to boast about Ulithi instead.
“It’s a shame the war didn’t last one more day,” he told his interrogators. “If it had, I would have slammed myself into an American aircraft carrier.”13
By the end of September, the U.S. Navy was comfortable enough operating the I-400 subs that the Sen-toku crews were no longer needed. Curiously, none of the subs was ever submerged. Presumably, nobody wanted to risk operating them on anything but the surface.
Before the Sen-toku crews were discharged, however, American officials visited them one last time.14 In appreciation for their cooperation, they gave the officers 20 cigarettes, a bottle of whiskey, and five ten-dollar bills. The same amount minus the whiskey was given to enlisted men. The gifts were a surprisingly Japanese thing to do—perhaps the American officers had learned something from their former enemies.
Before the translator departed though, he had important information to share.
“You will be released shortly, but the Allied War Crimes Tribunal will begin soon. The massacre of prisoners by submarines is a particular issue. If you are not careful, you may be arrested. Therefore, once you are released, it would be better to lay low.”15
The I-401’s crew was mustered out of the navy on September 30, 1945.16 By that time, the sub had been stricken from the IJN’s roster of active duty ships. After a morning truck ride to a nearby demobilization center, Nambu was promoted one rank and exchanged his summer uniform for a winter one. By noon he was wandering the streets of the city, a free man.17
CHAPTER 42
THE LONG ROAD HOME
WHEN THE U.S. NAVAL TECHNICAL MISSION TO JAPAN LANDED in Yokosuka in September 1945, navy officials were keen to identify the latest Japanese sub technology in case it proved useful. Undersea war experts were already examining Germany’s latest sub, the Type XXI, and though the state-of-the-art U-boat came too late to play a deciding role in the war, it was not too late to incorporate her design into the next generation of American fleet boats. U.S. naval officials already had a pretty good idea which Japanese subs they wanted to study, with the largest and the fastest at the top of their list.1 Any submarine that could travel around the world without refueling to launch multiple offensive aircraft against enemy targets was undeniably unique. Not surprisingly, the Sen-toku squadron made the short list.
Teams of U.S. experts quickly spread out to the sub bases at Yokosuka, Kure, and Sasebo, where senior Japanese officers were interviewed about Sixth Fleet sub programs. Rear Adm. Katayama, head of submarine design and construction, and Commander Fujimori, the Naval General Staff’s senior submarine officer, were extensively interviewed. Katayama had overseen construction of the Sen-toku force while Fujimori was familiar with her top secret operations. Both men spoke freely, helping U.S. intelligence assemble a clearer picture.2
Not everyone found the I-400 subs of strategic value; some considered them nothing more than white elephants. One British Royal Navy observer dismissed them as “hopelessly under motored and … the very devil to stop or turn in an emergency.”3
Though a report issued by the U.S. Navy analyzing the I-400 subs disparaged the Japanese as pipe fitters, it also noted that this “system will hunt.”4 As a result, all three subs were sailed to Pearl Harbor for further study.
THE 4,000-MILE VOYAGE to Hawaii began in November 1945, when the subs journeyed from Yokosuka to Sasebo. Lieutenant Commander McDowell captained the I-400, Cdr. Edward D. Spruance captained the I-401, and Cdr. John S. McCain, Jr. (father of the future U.S. senator), commanded the I-14. The subs remained in Sasebo for several weeks loading supplies, and in a surprising twist, Hi Cassedy took command of the I-14 from Jack McCain. Cassedy had been removed from commanding the I-400 after his run-in with Halsey over Japanese swords. Being a Lockwood disciple, he soon found himself back in favor. And since Cassedy was the most senior officer, he was put in charge of all three subs.
The I-400’s prize crew developed their own logo for the voyage. Painted on a pennant, it shows an American sailor with a bulbous red nose riding the I-400 with reins in one hand, a defeated Japanese soldier in the other. Subtle it was not.
Finally, on December 11, 1945, a minesweeper led the subs out of Sasebo harbor. The USS Greenlet (ASR-10) also accompanied the convoy in case one of the boats broke down. When the minesweeper reached the end of the channel, she blinked, “Bon Voyage” instead of the traditional “Good Hunting!”5 Now that the war was over, there was no reason to hunt.
When the Sen-toku subs arrived at Guam eight days later, they received a tumultuous welcome. Whistles blew, a brass band played, and navy officials lined up to tour the underwater aircraft carriers. Guam was also jammed with navy surplus. In a cashless economy, it was easily exchanged for Japanese war booty. Soon the subs’ aircraft hangars began filling with luxuries. Japanese rifles were exchanged for prime steaks; a coffee machine and General Electric ice cream maker joined the galley; and a porcelain toilet appeared in the I-400’s head. Even individual bunks were wired for music from a jukebox.6
Unfortunately, things didn’t stop there. An irate marine lieutenant stormed aboard the I-400 demanding that his motor scooter be returned. The chief of the boat assured the executive officer that “nobody is going to find any motor scooter in this boat.”7 The XO knew, however, that that wasn’t the same as saying there was no scooter to be found. Still, the marine was told to take the matter up with his motor pool sergeant. Strangely enough, when the I-400 sailed for Eniwetok,8 it was the Americans, not the Japanese, that had become pirates.
A brief stop at Eniwetok enabled the I-14 to repair her engines.9 Unfortunately, the I-401’s entrepreneurial crew found themselves in hot water when they were accused of stealing the island commander’s jeep. The sub was searched on the eve of her departure. The missing vehicle never turned up. When the I-401 was finally granted permission to sail, she was told not to return, or risk being fired upon.10
The Sen-toku subs arrived at Pearl Harbor on September 6.11 Cassedy had been informed that his subs shouldn’t appear until dark, to avoid antagonizing Japanese sympathizers.12 Since Cassedy was the highest-ranking officer, the I-14 would be first to dock,13 followed by the I-401 and I-400. Unfortunately, as the squadron approached the submarine base, a bolt shook loose from the I-401’s number-one engine mount. It was no time for screw-ups, but when the I-401 switched to battery power, her props sped up, and the sub shot past the I-14. Cassedy, always first, was fit to be tied.14 It didn’t help that a row of admirals and reporters were waiting at the dock.
The next day the local papers were filled with news of the Sen-toku squads’ arrival.15 The U.S. Navy recognized the publicity value of the subs and wanted to promote them. There was even talk of sailing them up and down the California coast, not to drop biological weapons but to raise money for war bonds. Until then, the subs were put on display at Pearl.
In February the I-400 went into dry dock. The pungent smell of barnacles rotting in the tropical sun filled the air as sub experts crawled over Kusaka’s former boat. The sub was extensively photographed both inside and out, and her systems were carefully
examined for features that might be incorporated into the design of future American submarines.16 A month later, Cdr. R. Kissinger issued a written report summarizing his findings.17
Though Kissinger found the sub’s overall construction to be sound and cited several features of interest, he was unimpressed. Curiously, he thought the I-400’s hangar carried four aircraft and noted that the sub’s purpose was “primarily for transportation of supplies, fuel, and planes to outlying islands.”18 Either Kissinger wasn’t paying attention, or some members of the United States Navy were still in the dark as to her true mission. This discrepancy would be resolved when the U.S. Technical Mission to Japan issued its report. It’s surprising though that six months after the I-400’s capture, the nature of her mission was still unclear.
THE FATE OF the Sen-toku subs was debated for several weeks.19 The I-400’s XO, Lt. Thomas O. Paine, argued that the sub should be refitted for submerged operation and further evaluated. As Paine wrote, “I was convinced we should find out how such a huge submarine handled submerged … [and] what lessons her Japanese naval constructors [had] incorporated into her design [as well as] all the other things she could teach us.”20 Another idea was to convert her into a transport sub.21
Military budgets were in decline, however, and there were no funds for refitting enemy vessels. Paine was told to “stand by and await further orders.”22 Though the U.S. Navy was eager to design a new fleet of submarines, it showed little interest in underwater aircraft carriers, particularly in the midst of a demobilization. When it was discovered it would cost three quarters of a million dollars and require six months’ yard work to refit the subs, decision making slowed to a crawl.23
On March 26, 1946, Lockwood attended the Submarine Officers’ Conference in Washington, D.C. The Sen-toku subs were among the topics of discussion. Kissinger’s report was reviewed, as were findings from the U.S. Naval Technical Mission to Japan. Several of the I-400’s “outstanding features” were singled out, including their sound protective coatings. Nevertheless, U.S. Navy officials found the subs too cumbersome and their number of aircraft too few to be of practical use. As the Technical Mission’s report noted, the I-400s had many differences from U.S. submarines, but “there is little of actual technical accomplishment … and few items of possible value to the United States.”24
It was agreed that no design studies should be made unless the Chief of Naval Operations believed the subs would be required in the future.25 In other words, U.S. naval officials had no interest in using Yamamoto’s underwater aircraft carriers.
The U.S. Navy might have lost interest, but the Soviets had not. When the Russians learned that the Sen-toku subs had been captured, they asked the United States to see them as part of an information-sharing agreement. The last thing U.S. naval officials wanted was the Russian military gaining access to a potentially disruptive technology. Given Soviet interest, U.S. officials denied the Russians access by scuttling Yamamoto’s subs.
In the Japanese version of Scapa Flow, 15 Sixth Fleet subs were slated for destruction. The I-402 was among the first to go. Early on the morning of April 1, 1946, in an operation called Road’s End, a skeleton crew of Japanese sailors piloted their subs out of Sasebo harbor. One crew fastened cherry blossom sprigs to their sub’s sail; another painted their sail bright green. Escorted by U.S. naval ships, the subs were led 60 miles off shore, where the water was 100 fathoms deep. Once the subs arrived, their crews were removed while demolition experts set explosive charges. Shortly after 1:00 P.M. the detonations began.26
The I-402 avoided that ignominious end, but not for long. Lashed to a second sub, she was used for target practice by the USS Everett F. Larson (DD-830). When the two subs stubbornly refused to sink, they were scuttled. Ariizumi must have been rolling in his grave.
Four days later nine more Japanese subs were scuttled, leaving only a handful of Sixth Fleet subs at Pearl Harbor. The I-14 was next. On May 28, 1946, she was taken eight miles off shore and used to test the newly developed Mark 10-3 exploder. The USS Bugara (SS 331) did the honors. Three days later the I-401 followed. At 10:51 on the morning of May 31, the USS Cabezon (SS 334) fired two torpedoes. Seven minutes later Nambu’s sub was gone.27
On June 4 it was the I-400’s turn. The newly commissioned USS Trumpetfish (SS 425) hosted distinguished guests for the fireworks, including Lockwood’s replacement and a medal of honor winner. As a PBY Catalina Flying Boat filmed the destruction, the Trumpetfish fired three Mark 18-2 torpedoes. One torpedo prematured, the other two struck in a sensational eruption of metal, foam, and fury. The I-400, the last of the great underwater aircraft carriers and the final Japanese submarine sunk by the United States during World War II, went down by the stern.28
The Russians filed a protest, but it was too late. The Sen-toku subs were already on the bottom. A headline in The New York Times read, “U.S. Said to Sink Four Japanese Subs to Balk Booty Bid.” A U.S. naval official was quoted as saying, “Russia strongly disapproved the sinkings and lodged a protest.”29 The United States wasn’t listening though—the cold war had begun.
CHAPTER 43
REDISCOVERY
THE OPERATIONS CENTER FOR THE HAWAII UNDERSEA RESEARCH Laboratory is located on Makai Pier, on the southeast end of Oahu. The pier is off the beaten track for most tourists. Wedged between the Pacific Ocean, Route 72, and a steep set of cliffs, its entrance is blocked by a chain-link fence. A shed in its middle, three stories high, is where the lab’s two deep-diving submersibles, Pisces IV and V, can be found.
Once you get past the hilarious acronym, HURL is a place where serious science is conducted. Funded by the National Oceanic and Atmospheric Administration’s (NOAA) Underwater Research Program and overseen by the University of Hawaii, HURL has a reputation in the world of submersibles as being the scrappy underdog. It doesn’t have the budget or staff of a Woods Hole, but what it lacks in funding, HURL makes up for in ingenuity and moxie.
The world of deep-diving submersibles is an elite and expensive club. France has the Nautile; Russia has the Mir 1 and 2; Japan has the Shinkai; China has the Jiaolong; and the United States has Alvin. Though the Pisces IV and V are the “shallowest” members of the club, with an operating depth of only 6,500 feet, they still accomplish a lot.
Because of budgetary constraints, HURL can’t spend millions training its submersible pilots on an expensive simulator. Instead, they use the Pisces manipulator arms to practice picking up coffee cups off the ocean bottom. The U.S. Navy dumped them there by the thousands at the end of World War II and every desk at HURL’s operation center boasts at least one of these ceramic mugs as a pencil holder. The cup on the desk of Terry Kerby, HURL’s operations director, is stamped January 1943.
Since HURL was founded in 1981, it has made a name for itself not only by exploring the hydrothermal vents near underwater volcanoes but by finding important historical artifacts, like two of Ariizumi’s previously unaccounted for midget subs. Kerby has been involved with HURL operations since their beginning. Blond, blue-eyed, and remarkably fit, he looks at least ten years younger than his age, which is what you’d expect for a man who swims two miles in the ocean every day. Wearing a dark T-shirt and khaki shorts, he is both tan and casual as he explains some of HURL’s outsize discoveries.
Kerby was prompted to look for Ariizumi’s midget subs by the fiftieth anniversary of the attack on Pearl Harbor. Up until 1991, only three of Ariizumi’s five type-A midgets had been accounted for. One washed ashore shortly after the attack and was captured; one penetrated the harbor, was sunk, then raised weeks later, only to be used for landfill with its crew still inside; one was discovered off Oahu in the 1960s; and one was presumed sunk by the USS Ward (DD-139) but never found. The location of the fifth and final midget sub was a mystery.
Kerby couldn’t use science assets to go “treasure hunting” though. It cost upward of $40,000 a day to operate the submersibles, so any search for Ariizumi’s midget subs had to come as a by-product of a preexi
sting operation. Maritime artifacts were a secondary consideration.
Fortunately, HURL conducts test dives off Oahu at the beginning of each season to review safety protocols and ensure that each submersible is functioning properly. In August 2002 Kerby bested Dr. Robert Ballard, discoverer of the Titanic, when he found Ariizumi’s fourth midget sub. Ballard had conducted his own search for the midget in 2000 but came up empty-handed. After ten years of looking, Kerby found the midget right where the Ward had sunk her, four miles south of Pearl Harbor, in 1,200 feet of water. The sub was remarkably well preserved despite the hole in her sail. Since her crew had the dubious distinction of becoming the Pacific War’s first casualties, Kerby left the sub undisturbed.
Kerby and Ballard are more colleagues than competitors. The two men have worked together, so it’s hardly a rivalry. Still, HURL’s find generated so much positive publicity that the National Park Service and NOAA’s National Marine Sanctuaries encouraged them to explore further. As a result, Kerby set his sights on finding the fifth and final midget. He’d discovered her tail section in 1992. Subsequently he found two more sections, including the midget’s bow.
It wasn’t clear how the midget came to its final resting place or how it ended up in three neatly sundered pieces. Working with experts hired for a NOVA documentary, Kerby deduced that the sub had gotten lost either entering Pearl Harbor or trying to escape. When she ended up in the West Loch, her crew probably settled on the bottom, detonated the sub’s self-destruct charge, and disappeared into history.
The U.S. Navy accidentally rediscovered the midget while cleaning up after an explosion in May 1944. The midget was dredged up along with other debris, cut into sections, and dumped at sea without anyone realizing what they’d found. It was only when Kerby discovered all three sections that the puzzle came together.
Operation Storm: Japan's Top Secret Submarines and Its Plan to Change the Course of World War II Page 36