White caps flecked the sullen blue waters of the Pacific off the rocky shores of Honshu, Japanese mainland. It was noon, August 27, 1945, twelve days after the Mikado had told his people to lay down their arms, a week before the signing of surrender terms.
High overhead a lone U.S. Navy pilot, on routine patrol, jammed his rudder hard right. He wanted a better look at a huge dark object, half awash, moving slowly on a northward course.
It was too big to be a whale, and, as the pilot spiralled “down stairs” his startled eyes told him it was even loo big to be a submarine!
But it was a sub, the biggest and most fantastic submarine in the world. The pilot was getting the white man’s first good look at one of Japan’s most closely guarded secret weapons—the “underseas carrier.” Even half awash she was immense, incredible, like a long black floating island.
Her northward course indicated that she might be trying to escape, perhaps to hide in one of the scores of cloudy little harbors in the Kuriles. Yet from her conning tower flapped the black colors designated in radio broadcasts to all Japanese ships as the sign of surrender.
The pilot reached for his microphone.
“Japanese sub flying surrender colors contacted Latitude 38°40' North, Longitude 145°12' East,” he reported laconically to the Third Fleet.
The message was promptly intercepted by the U.S.S Proteus, submarine tender with a support force en route to Tokyo Bay. Captain L. S. Parks, commanding officer of Submarine Squadron 20, had been awaiting word of enemy sub surrenders at sea, although neither he nor anyone else in Subron 20 had any idea of the real importance of the first prize. Twelve groups of expert U. S. Navy submariners, officers and enlisted men, had been briefed to act as boarding parties and prize crews. They whipped their gear together, awaiting official orders from the Third Fleet command.
High excitement reigned in the Task Group. Jap submariners were a picked lot, fanatically devoted to their emperor. Would they, despite the surrender flag, try to resist boarding parties, or use their torpedoes on ships approaching them? No one had had any dealings with surrendered Jap submariners, in fact, no one had yet been ashore in Japan. A few surrenders in lonely islands and atolls were no guarantee that the Nips would not renege on their home grounds.
The boarding party groups (4 officers, 40 men) had been hurriedly schooled in prize crew techniques, but they had been carefully selected from a large number of volunteers for their resourcefulness, knowledge of subs and awareness of Japanese wiles gained on many a patrol in enemy waters.
As each group wanted the honor of bringing the first Jap submarine prize into port, the accolade had to be settled by dealing poker hands to each of the twelve group leaders. This “showdown” was won by Commander Hiram Cassedy, a chunky Irish veteran of war patrols in the Sailfish, Sea Raven, and Tigrone. His little band of 20th Century corsairs were champing at the gangway of the Proteus when the official word came from Halsey to “go fetch.”
“In the destroyer escort Weaver we steamed along at high speed all afternoon,” Cassedy recalls. “Then just after dark we saw ahead something large and black, obviously an enemy submarine, accompanied by an American destroyer. Our hearts sank because we thought our prize had been taken.
“No, it was a smaller Jap sub, the second to be reported, and it had not been boarded because the DD did not have any trained submariners aboard. As it was heading peacefully enough toward Tokyo Bay with its DD escort, we went on through the night toward the area off northern Honshu where our carrier plane had made first contact.
“In the early morning light I thought I could make out a submarine ahead, but it was so huge and it had such a strange silhouette, I could scarcely believe my eyes. An enormous hulk she was, bigger than any submarine I had ever seen, or even heard about. From her tall conning tower a black flag flapped in the brisk offshore breeze.
“That conning tower was a startler, too! All cock-eyed it seemed, because it rose from the port side, instead of amidships, and it bulged around a deck housing that extended a full 100 feet, at least. Why, that housing alone was longer than Holland’s original submarine! Beyond the housing the deck ran fore and aft about the length of a football field. What a ship!”
The big craft was hove to, in the custody of the U.S.S Blue. This destroyer had also intercepted the patrol plane message and the orders from the Third Fleet. Being in the neighborhood, she had dropped over to take charge until the official prize crew arrived.
The Blue, a new 2,200-tonner, actually looked small alongside of the massive submersible. In the measured breathing of the sea the Jap sat almost as solid as a rock, while the Blue rolled and pitched as cans always do. The Blue’s boarding party, not being submariners, had remained on deck.
“We realized at once that our bag was something pretty special,” Cassedy reports. “So we hurried over with the official boarding party, including an expert translator. He soon learned that she was one of the I-400 class, underseas plane carriers, and the biggest subs in the world. We knew nothing about them, only rumors, and you can gamble that we were all eager to bring this one back ‘alive.’
“Not a bit of trouble developed, however, at least not with this boat. Later, in picking up a sister ship, the I-401, we all got a real scare, and I’ll come to that. But here the Blue really had the situation well in hand, so our prize crew, relieving the Blue’s boarding party, had an easy time of it.”
The Japanese were polite but not cordial.
“After my prize crew had inspected below decks for torpedoes and ammunition, and found that they had been disposed of as required by surrender terms, we locked all valves to prevent the Japs from diving the ship and placed men at the various control centers.
“I then informed the Jap captain that my commands would be obeyed, that his vessel was now a prize of war, and under the orders of Admiral Halsey,” Cassedy continued. “The tears in his eyes as he hauled down the Rising Sun emblem and hoisted the United States flag could be well understood.”
Orders were given to get under way, and, with the Weaver as escort, the I-400 headed for Sagami Wan and rendezvous with the U.S.S Proteus.
Cassedy wanted as much information about the huge ship as he could get for his preliminary report, but the Japanese captain at first was evasive, giving answers to Cassedy’s questions that obviously were misleading. Then he noticed a dolphin pin on the American’s shirt.
“He wanted to know if I were in the American submarine service,” Cassedy recalls. “When I told him that I and all my officers and men were veteran submariners, and had been on combat patrols, he bowed deeply and from then on was most cooperative. As a ‘brother Elk’ he would forget race and nationality, and tell all—that is, ‘almost all.’ At any rate he must have realized that the prize crew, as sub experts, would get a lot of the answers they wanted, just by looking around.
“He seemed to have things on his mind, and this must have been his first chance to spill them.” Cassedy added. “I let him talk, not only because there was a lot I wanted to know myself, but also because prisoners usually clam up when they get before boards later.”
The sub monster was the first of her class, less than a year old. Yes, she was one of Japan’s five “underseas carriers,” built in deepest secrecy and designed to destroy the Panama Canal. She and her sister ships, the I-401 and I-402, could each carry three seaplanes, and parts for a fourth, in the long, domed housing, or hangar, amidships.
That was why the conning tower rose from the port side—to allow freeway for the hangar. Float planes were launched by hydro-pneumatic catapult from a track that ran the length of the foredeck to the bow, and were recovered by a heavy crane, that folded flush into the deck when not in use.
The I-400 and her two sister ships each were 400 feet long, had a 40-foot beam, and a surface displacement of 5,700 tons. They were far bigger therefore than the ill-fated French giant Surcouf (2,880 tons), or the biggest American sub ever built, Argonaut (2,710 tons). Both of the latter were lost at sea during the war.
The Japanese Navy had two other plane-carrying subs, the smaller I-14, which Cassedy and his men passed at sea the day before, and the I-15. These carried two planes each.
When captured the I-400 was carrying no planes. In fact, she did not even have a torpedo or any ammunition, having, obeyed the radioed surrender instructions to jettison all torpedoes and shells. She carried quite a heavy load of provisions, however, so it was obvious that this class of sub was now being used to supply starving garrisons of bypassed Pacific outposts.
However, it is believed that they made at least one pass at the Panama Canal. The only evidence is a set of charts found hidden on the I-14 and the I-401. These indicate that the I-400, the I-401, and two smaller Japanese subs made a reconnaissance cruise of the eastern Pacific in 1945. On June 7, the charts show they were ten miles off the coast of Colombia, opposite the Gulf of Panama, within striking distance of the Canal.
Why they did not try to slip, submerged, inside the radar picket patrol that guards the western approaches to the big ditch, and launch their planes for a suicide mission on the locks, is not known. Once inside the radar fence, their planes might easily have been mistaken for our own.
There again is evidence that the Japanese as operators (fortunately for us) did not measure up to some of the dreamers of their planning, engineering and strategy boards. They had the tiniest as well as the biggest subs, the biggest battleship, and some curious combinations of craft, such as the hermaphrodite carrier-battleship. But apparently the men who went down to the sea in Nippon’s ships lacked that daring, or “Sunday punch,” which is the symbol of military genius.
At 9:15 A.M., August 29, Cassedy brought the I-400 triumphantly up alongside the submarine-tender, whose officers and crews stared in bug-eyed amazement at the strange monster conjured from the depths. A half hour later the I-14 also was tied up alongside.
Meanwhile disturbing reports had been received about the I-401, sister ship of the I-400, still at large. She was flagship of the “underseas carrier” squadron and the commodore aboard was rumored to have an intense hatred of Americans. Jap officers on the I-400 did not believe he would surrender without a fight. Patrol planes redoubled their efforts to spot the fugitive, but without success.
Finally she was intercepted on the high seas by, all of things, another submarine— the alert U.S.S. Segundo, an American boat only a third her size. In the gathering darkness the Segundo ordered the I-401 to heave to, which she did. There was a prolonged megaphone conversation, the gist of which was that the Japanese commander would receive a boarding party of five. If more were sent, or if an officer accompanied them, he threatened to sink his ship.
Lt. Comdr. John-E. Balson went over with four men, but Balson wore no insignia. There was obviously trouble aboard, so the men could not get below decks. The Japs were using their radio furiously. Japanese Navy Headquarters in Tokyo sent a message to Admiral Halsey, informing him that the I-401 should not be brought into the vicinity of our ships, as she might be dangerous.
Nevertheless, Comdr. S. L. Johnson, of the Segundo, gave orders for the I-401 to get under way, direction Tokyo. The radio also was to be silenced. The Segundo was taking no chances of its being used as a homing device for some unreconstructed Kamikaze flyer, a few of which had just been shot down “in a friendly fashion” by some of Halsey’s airmen.
During the night the I-401 stopped dead in the water, and remained stopped most of the night, despite the Segundo’s efforts to keep her moving. The Segundo would have been justified in sinking her at this time, but dared not because five of the Segundo’s men were on board.
In the meantime another American submarine, the Tigrone, had arrived to lend a helping hand, if necessary. In the gloom one of the boarding party thought he saw something large and heavy being thrown overboard from the Japanese sub. Code papers? No, it looked larger than that, he believed. A body? Maybe, he couldn’t be sure.
Later there were reports that it was the body of the Japanese Division Commander, who would not surrender. Perhaps he committed hari-kari, or the Japanese captain of the I-401 killed him. This could not be confirmed. In fact, the Japs would answer all questions except those concerning the trouble aboard. Here they became again the inscrutable Oriental.
At any rate, a short time after the mysterious bundle disappeared in the dark waters of the Pacific, the I-401 again got under way, and, flanked by the two American subs, proceeded docilely to the entrance of Sagami Wan. Here a prize crew under Commander A. C. Smith took over, and there was no further trouble.
The Proteus moved inside the breakwater, and soon the world’s only “underseas carrier” squadron was nested alongside of her. In contrast to the sleek, but much smaller, American subs tied up nearby, the Jap giants looked like prehistoric monsters. And like the diplodocus or the mighty brontosaurus of old, they, too, were apparently too big to survive.
Nevertheless everyone in Subron 20 was anxious to pick their bones. Now was the time to ask questions of the officers and crew, too, while the enemy was still off balance from the shock of a sudden surrender. Later, intelligence officers knew, they would not talk so freely.
There was a brief pause for Surrender Day. During the signing of the ceremonies on the U.S.S. Missouri, September 2, the three-star flag of Vice Admiral Charles A. Lockwood, Jr., Commander of Submarines Pacific, flew from the conning tower of the I-400, once pride of the Japanese underseas fleet.
First job was a big cleanup. By American standards of spotlessness in anything afloat, the Jap subs were indescribably filthy. So dirty, in fact, it was decided first to fumigate. Three bushels of rats were part of the “harvest.” Waste of all kinds lay around, and the food stench was so bad that one foggy night a liberty boat from the Proteus came unerringly home when it got to leeward of the three Jap subs, using the smell as a beam!
Cleanup and unloading kept the Jap crews busy for several weeks. The fate of the big craft had not been determined, but the were to be made ready for sea trials by American crews. Much rice, crab meat, and canned foods had to be removed.
During this tedious operation one of the Japanese petty officers got into a quarrel with an American seaman. He boasted he had killed many Americans during the war, and finally made himself so obnoxious that he was locked up in the Proteus brig. When he came to his senses, he became obsessed with the idea that he would soon be executed. He even wrote a farewell letter to the American captain of the I-401 in Japanese. Here is a translator’s copy:
“To be delivered to the Captain of the I-401, from CPO, Intendence, Morita.
“I beg permission to write you briefly. If I have caused any anxiety, I have no available excuse and must beg a thousand pardons. Actually this present affair has occurred as unexpectedly as a bolt of lightning from a clear sky, and over it I have suffered severe disappointment. However, since I have already come to this place, I am left with nothing to say. But I assure you that even in these straits, I am upholding to the end the countenance of a worthy scion of the Japanese spirit. May I request in especial that you do me the favor of telling my people at home that I died manfully in battle.
“Death Song:
“The Samurai spirit of the eastern land where the cherries bloom,
Is scattered and fragrant with a fragrance which will not fade nor die,
And I remain as bravely clean as the mountain cherry flower.”
In Morita’s behalf one of the Japanese officers of the I-401 also addressed the American prize crew captain, in English:
“Sir: I-401 Captain: September 14, 1945
“By interview I should state this fact to you, but, since I am not familiar in my conversation, please excuse me for my written matter.
“In the past few days 2nd Petty Officer, Morita, one of my crews, has been imprisoned in the tender, and I really believe that he has now confessed and remorsed for what he has done.
“Hereafter, I will strictly watch him that he will never do such a thing again. Therefor, this time, with special kindness, please give him permission to be emancipated and to be returned. I implore.
“Yours sincerely,
“Lieut. Comdr. Nambu.”
Needless to say Morita was released, but for a week he seemed dazed, so certain he was that he would never leave the tender alive.
Mechanically, the super-subs were found to be in good condition. They were fitted with the latest Schnorkel device for operating the Diesels while submerged. They had ample anti-aircraft batteries and search radar.
Topside everything was covered with antisound paint, to impede sonar detection.
The I-400 class dimensions and other vital statistics are almost unbelievable: 400 feet long, 40 foot beam or width, 24 foot draft, and a cruising range from 25,000 to 30,000 miles. On the surface they could make 16 to 19 knots; submerged 5 to 7 knots. Two torpedo rooms forward, one above the other, had six tubes each, so that a deadly spread of torpedoes could be fired when a close- packed convoy offered itself as target.
Fuel tanks held 508,000 gallons of oil, enough to fill 15 railway tank cars, or heat 300 average homes for a winter. Four diesel engines operated two screws. A big 105 mm gun aft discouraged surface pursuit. They had been test-dived to more than 300 feet.
But the real innovation, of course, was the huge plane hangar amidships. Its cylindrical interior, 12 feet in diameter and 102 feet long, could house three Seiran-type seaplanes with wings folded. Along the walls was space for enough parts to assemble a fourth plane.
The planes emerged from a half-dome door, that swung on heavy hinges to starboard. Takeoffs were from a track in the foredeck, 85 feet long. A heavy steel crane, that folded flush into the foredeck when not in use, recovered the planes.
However, the Japs had not had much practice with the I-400s as “carriers.” One of the officers recalled a drill in which three planes had been used.
“How long did it take you to launch them?” Commander Cassedy asked.
“About twenty minutes,” he answered.
“How long did it take to recover your planes?”
“We never got any back,” he replied, sadly.
Whether they were lost, or whether they just flew off somewhere else, he did not know. But he did not think it was remarkable or important, because the Seiran seaplanes were to be replaced soon with the suicide 53-type Baka jet-propelled bomb. Meanwhile the big subs had been pressed into cargo and transport service.
Japan’s submarine force, as a matter of fact, took quite a kicking around from the rest of the Japanese military, including the Japanese Navy. It never had a chance to prove itself as a strategic arm (as did ours), but was subordinated to local needs and tactical situations.
For instance, Japanese submariners were told to confine their efforts to warships and to leave merchant shipping alone. Japan did not do this because of humanitarian principles, nor out of regard for any existing treaties; but rather from the firm, and quite possibly correct, conviction that U. S. carriers, battleships and cruisers were the greater threat to her chances of successfully concluding the war.
Despite some notable successes, the sinking of the carrier Wasp and the cruiser Indianapolis among others, the achievements of the Japanese submarine force must have been very disappointing. Part of the fault lay in training and equipment, but a good deal of the blame can be placed at the door of the high command, and stunted ideas of submarine missions and capabilities.
For several weeks after the war, the fate of the super-subs was debated among underseas warfare experts. Finally it was decided that they had no place in any of our plans, or, if need for such craft should arise, it would be better to build our own, drawing what we needed from plans of the Japanese. The U. S. Navy experimented with a plane-carrying submarine in the mid-twenties, but found no practical use for it. The French and British have also given the idea a trial, but their planes were intended primarily for reconnaissance.
At Sagami Wan, meanwhile, Jap crews instructed our submariners in operating the huge boats during short cruises off the coast. No dives were attempted, and no planes launched.
Finally came orders to sail them to Hawaii. There, one bright day, they put to sea on their last voyage. Ironically they left Pearl Harbor by the same channel that their midget-submarine cousins had slipped in before dawn, December 7, 1941!
Target practice did not last long. Even super-subs cannot take much shelling. And the redoubtable Davey Jones, who welcomed many a strange visitor in the preceding five years, must have been a bit startled when their gargantuan hulks finally settled in his locker!
Is this the end of the saga of the “underseas carrier”? We have no plans for any such craft. Whether anything similar is being built by Russia, whose principal naval weapon is the submarine, we do not know.
Some experts, civilian and military, say the submarine is the ideal means of transporting a bomb-carrying plane, or for launching rockets or guided missiles. They claim that such weapons can be carried through radar screens or picket patrols with less chance of detection by submarine than by any other method.
But the bigger the sub, the bigger the target, particularly when caught on the surface or when bracketed by aerial sonar buoys in coastal waters. Hence American emphasis on smaller improved Guppy types, equipped with Schnorkels.
Dan A. Kimball, Under Secretary of the Navy, made some noteworthy comments on U. S. submarine developments at New London, Connecticut, last June.
“Increases in speed and range may be expected for the submarine of the future,” he told the graduates of the Submarine School. “The employment of guided missiles will have a pronounced effect on its size.
“Not so long ago, the higher submerged speed at which submarines now operate seemed inconceivable. But this higher speed is now also a reality and has created vastly different control problems. Even though the highest speed of a submarine is, of course, only a fraction of the speed of an airplane, it might now be said that submarines no longer will be merely propelled through the water—they will be flown through it.
“This leads one to speculate whether the submarine officer of the future may not turn into a kind of underwater aviator, and the dolphins on his pin turn into flying fish.”