Aircraft Carrier IJN Shinano: The Largest Warship Ever Sunk by a Submarine

Summary and Key Points: The IJN Shinano, initially a battleship converted to an aircraft carrier, was sunk by the USS Archerfish on its maiden voyage in 1944. Despite being a massive and powerful warship, Shinano succumbed to four torpedo strikes from the Archerfish.

-The secrecy around Shinano's construction was so tight that the U.S. initially misidentified its sinking.

-The Archerfish's crew received commendations for their success in this remarkable naval encounter.

How the USS Archerfish Sunk Japan's Mighty IJN Shinano

Those of us who are old enough to remember the 1980s might recall the short-lived ABC series Supercarrier starring Robert Hooks and real-life retired U.S. Marine Corps Capt. Dale Dye. For some of us, this show might be what comes to mind when we hear the term, “supercarrier.” 

Regardless of age bracket, though, seapower-savvy folks will also think of the U.S. Navy's mighty aircraft carriers – vessels such as the USS John F Kennedy and USS Abraham Lincoln.

However, the Americans weren't the first nation to build a supercarrier, nor were the Russians.

That distinction goes to Imperial Japan, with its naval behemoth Shinano. Alas, the Imperial Japanese Navy couldn't really claim much in the way of bragging rights, as the IJN Shinano was sunk rather abruptly and unceremoniously by a comparatively small submarine, the USS Archerfish.  

Profile of the Predator: The USS Archerfish

The submarine's flesh-and-blood namesake is even smaller — typically 5 to 7 inches in length — but it is still quite the predator. Inhabiting fresh and brackish waters across South Asia, Southeast Asia, Northern Australia, and Melanesia, this little critter gets its name from its habit of preying on land-based insects, spiders, and even small lizards by shooting them down with water droplets from their specially evolved mouths.  

Needless to say, the USS Archerfish (SS-311) — a Balao-class submarine — carried even deadlier arrows in its quiver. These included 21-inch torpedoes — six torpedo tubes fore and four tubes aft — one 4-inch (102mm)/50-caliber deck gun, as well as Bofors 40mm and Oerlikon 20mm anti-aircraft guns. Her keel was laid on Jan. 22, 1943, and she launched on May 28 of that same year. Displacing 1,526 tons with a surfaced speed of 20.25 knots and a submerged speed of 8.75 knots, the Archerfish was skippered at the time of her record-breaking achievement by Comm. Joseph Francis Enright.  

Profile of the Prey: The Aircraft Carrier IJN Shinano

The Shinano, whose keel was laid in May 1940, actually started off her star-crossed life as a battleship.

Not just any battleship, mind you – the Shinano was a sister ship to the Yamato and Musashi, the world's most powerful battleships. They displaced 72,000 tons and packed nine massive 18-inch guns. However, the IJN's disastrous loss of four carriers at the Battle of Midway prompted IJN planners to change course and begin modifying Shinano to act as an aircraft carrier. 

From there, a bureaucratic turf battle ensued. As noted by Kyle Mizokami: 

"Navy officials argued about her ultimate design: One faction demanded Shinano be outfitted as a real aircraft carrier. Had she been so, she would have been the largest carrier in the world, with an overall length of 872 feet—fifty feet longer than the U.S. Navy’s Essex-class fleet carriers. Another faction wanted Shinano built out as a support ship for other carriers, carrying spare parts, fuel, ammunition and spare airplanes for Japan’s carrier fleet. Shinano would not participate in combat and indeed would have no facilities for storing aircraft of her own. Ultimately, a compromise was hammered out in which the ship would act as a support ship for the rest of the carrier fleet but also carry forty-seven fighters for her own protection."

The conversion brought Shimano's displacement down to 69,000 long tons. But it all turned out to be a moot point. At least Yamato and Musashi went out in the proverbial blaze of glory, sunk while firing their guns in anger. And the Yamato gained a fictitious second lease on life in the classic anime series Space Battleship Yamato (retitled Star Blazers for American TV audiences). No such luck for sister Shinano. 

The Sinking of an Aircraft Carrier

At 6 p.m. on Nov. 28, 1944, Shinano departed Yokosuka Naval Base for her sea trials. At 8:40 p.m., Archerfish, on her fifth war patrol — and with no prior ship kills — picked up the supercarrier on her radar and took up pursuit on a parallel course. The pursuit dragged on for hours, but at 3:15 a.m. on Nov. 29, the carrier inadvertently presented her broadside to the submarine, making Shinano a very juicy target. Comm. Enright launched six torpedoes, four of which hit the carrier. Archerfish then dove to 400 feet — thus incurring a high risk of hull crush depth — to ride out the retaliatory depth charge attack.

The third torpedo strike was particularly disastrous, flooding the No. 3 boiler room and killing every man on watch. From there, structural failures caused the two adjacent boiler rooms to flood as well. The stricken carrier's crew was unable to counter the flooding, so in desperation the ship's skipper, Capt. Toshio Abe, attempted to have the escorting destroyers tow the carrier toward shore in the hope of beaching her, but it was a lost cause. At 10:18 a.m., Capt. Abe gave the order to abandon ship, and at 10:57 a.m. the ill-fated vessel finally capsized. It sank stern-first with a loss of 1,435 officers, enlisted sailors, and civilians. There were 1,080 survivors. 

Capt. Abe chose to go down with his ship. His watery tomb was the largest warship ever sunk by a submarine.

Afterword

Japanese secrecy surrounding the Shinano had been so airtight that the U.S. Office of Naval Intelligence didn’t even know it was being built. Initially they only credited Comm. Enright with sinking a cruiser, then later upgraded the credit somewhat to that of a 28,000-ton Hiyō-class escort carrier. All's well that ends well, however. The submarine received the Presidential Unit Citation, and Enright was awarded the Navy Cross. 

Joe Enright retired from the Navy in 1963 at the rank of captain, and passed away in Fairfax, Virginia on July 20, 2000, at the age of 89. He was laid to rest at Arlington National Cemetery. 

About the Author

Christian D. Orr is a former Air Force officer, Federal law enforcement officer, and private military contractor (with assignments worked in Iraq, the United Arab Emirates, Kosovo, Japan, Germany, and the Pentagon). Chris holds a B.A. in International Relations from the University of Southern California (USC) and an M.A. in Intelligence Studies (concentration in Terrorism Studies) from American Military University (AMU). He has also been published in The Daily Torch and The Journal of Intelligence and Cyber Security. Last but not least, he is a Companion of the Order of the Naval Order of the United States (NOUS).