Key point: Shinano is the biggest warship ever sunk by a submarine.
The first torpedo struck farthest aft. Over the next 30 seconds three more warheads detonated against the massive aircraft carrier’s hull, working their way forward. The explosions and instant flooding immediately killed scores of men, many asleep in their bunks.
As tons of seawater cascaded into the wounded colossus, men below deck could see the extent of the damage, were seized with panic, and stampeded topside. The missiles had hit 10 feet below the water line, and on the bridge and upper levels the commander and his officers were not yet aware of how sorely they were hurt. Many had survived earlier torpedo attacks, and aboard less formidable vessels than this one. Even as their gargantuan ship began to list, they remained optimistic.
“Expressing the Flavor of an Ancient Samurai”
As 1944 neared its end, the tottering Japanese empire toiled terribly to find ways to hold off U.S. forces as they advanced ever closer to the Home Islands. U.S. troops under General Douglas MacArthur were resolutely reclaiming the Philippines. Huge Boeing B-29 Superfortress bombers were beginning the destruction of Japan’s major cities. Perhaps most devastating were the omnipresent U.S. Navy submarines that were sweeping Japanese shipping from the Pacific. Yet, if the Imperial Navy could produce a single monster of a warship perhaps it could at least temporarily stem the advance of the enemy. Maybe this floating megaweapon could even check or turn back the Philippine liberation and abort the anticipated attack on Okinawa.
The aircraft carrier Shinano started out as the third sister of a planned trio of super battleships that included the 70,000-ton Musashi and the Yamato. After the crippling loss of aircraft carriers inflicted on the Japanese Navy at the Battle of Midway, Shinano’s construction was altered to instead make her into the largest carrier ever to float. Named for a province of medieval Japan, Shinano’s builders hoped to have her seaworthy in her redesigned state by February 1945, yet rapidly waning military fortunes resulted in a quickened pace of construction. Overworked shipyard workers toiled in 16-hour shifts to complete the great warship.
Captain Toshio Abe, a graduate of the Japanese naval academy, was assigned to command Shinano. A survivor of the crushing defeat at Midway, where he had commanded a destroyer, he was a humorless, undiplomatic, and highly competent career officer. His newly assigned medical officer, Lt. Cmdr. Takamasa Yasuma, later described him as “expressing the flavor of an ancient samurai. He seemed to be a man of strong will and apparently was respected by his officers and men.”
From the Desk to the Seas
Abe’s future adversary, Joseph Francis Enright, was a 1933 graduate of the U.S. Naval Academy at Annapolis. As a lieutenant he was given his first command, the submarine S-22, immediately after Midway. She was an old sub used for training young sailors in undersea warfare. In the spring of 1943, Enright was promoted to lieutenant commander and placed in command of the submarine USS Dace. Embarking on his first war patrol late that year, he was not pleased with his own performance. He stalked and lost a succession of ripe military and merchant targets. At one point, because of an overcautious approach during which he ignored his gut instinct to attack aggressively and instead made a time-consuming, by-the-book stalk, he botched an excellent opportunity to attack the aircraft carrier Shokaku. Enright returned to Midway on December 11 without having fired a shot.
On his own recommendation, Enright was relieved of his command. He was then promoted to full commander and assigned the desk job of executive officer of Midway’s submarine base. In a study of wartime irony, Enright’s career at sea was rescued by a poker game.
His spirits were lower than ever late in the summer of 1944. His mother had died suddenly back in the States, and he was stuck in an administrative position where he could make no significant contribution to the war effort. He wrote a letter to the Midway naval base’s commander, Admiral Charles Lockwood, requesting another submarine command, but received no response. Then Enright wound up in a late-night card game with one of Lockwood’s subordinate commanders, a Captain Pace, who was impressed with Enright’s fearless and aggressive style of poker playing. At the game’s conclusion Pace asked Enright, “Joe, would you run a submarine the way you play poker?”
“Okay Joe, I like your spirit. You can have the next available submarine.”
Shinano: Japan’s Secret Super-Carrier
On September 24, 1944, Enright was discharged from his desk and given command of the USS Archer-Fish, which was just returning from her fourth war patrol. He rode his new boat from Midway to Pearl Harbor, where she was intensively serviced, her stores replenished, and her crew rested and rotated. Under her new skipper she set forth on her fifth war cruise on October 30, 1944. She and her men had a whale of an adventure awaiting them.
Almost as crucial as Shinano’s weaponry was the secrecy under which she was built. If the Americans learned of her presence in dry dock no. 6 of Yokosuka Naval Shipyard on the west shore of Tokyo Bay, they would dispatch their B-29s to pound her into rubble before she could take to her native element. Besides, if she could be completed and sent into action without the Allies knowing, her sudden appearance off the Philippines would be a devastating shock for them.
Shinano was constructed within a massive, roofed concrete fence. Her dry dock was off limits to anyone not involved in her building. Imperial Kempei secret police patrolled the construction site, ensuring none of the sequestered workers left its confines, where they lived and worked seven days per week. The laborers were threatened with imprisonment or execution if they revealed the ship’s existence. Cameras were forbidden. Shinano was the only major warship built during the 20th century that was never officially photographed while under construction.
The carrier was a formidable weapon. She was fitted with an eight-inch-thick belt of armor above and below her water line. She bristled with 16 5-inch, high-angle guns; 145 25mm cannons; and 12 4.7-inch rocket launchers capable of firing salvos of up to 30 projectiles. She was also fast. Her four main steam turbines could produce 150,000 shaft horsepower to push her along at up to 27 knots. Multiple fuel tanks gave her a range of 10,000 miles. With a full-load displacement of 71,890 tons, Shinano was the biggest aircraft carrier built up to that time. Not until 1961, when the nuclear-powered USS Enterprise was launched, would any carrier exceed her in size.
A Bad Omen for Shinano
With the war going badly for Japan, the naval high command ordered the shipyard to deliver the behemoth four months earlier than planned. On October 5, 1944, the massive maiden made a memorable entrance into her native element. At 8:00 that morning, the 5,000-ton caisson being used as a dry dock gate suddenly gave way with a shattering crash as its sealed dry dock seat unexpectedly yielded to the enormous force of water pressure. With the level of water in the bay much higher than the floor of the dry dock, tons of seawater flowed into the dock, lifting massive Shinano and hurling her forward like a cork 100 feet into the dock’s headwall while 140 mooring lines snapped. As the invading water surged into the confined dry dock, it hurled the carrier back and forth three times until the water level inside and outside the dock equalized and the motion died down. By some miracle nobody was killed, although scores of sailors and workmen on the ship and in the dry dock were injured.
New workers and sailors were conscripted to replace the wounded. None came willingly, for as Shinano’s self-inflicted damage was being hastily repaired superstitious seamen were already whispering that the accident was an ill omen and this mammoth maiden was jinxed. When she put to sea, her crew’s morale would be affected accordingly, and many of her men were not surprised when her fate (and theirs) came quickly.
The carrier steamed from the shipyard for builder’s trials on November 11, and civilian authorities delivered her to the Navy nine days later. That same day intelligence officers briefed Captain Abe on reports that American submarines had sortied from Saipan and Guam on November 10 and 11, presumably headed for the Home Islands. In hopes of evading these predators, Abe waited until after nightfall on November 28 to take his ship out of Tokyo harbor and head south. His course was to sail past Iro Saki and To Shima and finally into the Inland Sea port city of Kure to the west, where he would take on his aircraft.
Shinano was to carry 20 fighters, 20 bombers, and seven scout planes. She already packed 50 Ohka suicide planes and six Shinyo suicide speedboats. Destroyers Isokaze, Yukikaze, and Hamakaze escorted the carrier. Had they suddenly popped up off some contested island, Shinano and her destroyers would have been a bitter shock to the Allies. First, though, Abe had to get his fleet fully armed.