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I-168: The Submarine That Sunk the Aircraft Carrier USS Yorktown

USS Yorktown
The U.S. Navy aircraft carrier USS Yorktown (CV-5) anchored in Hampton Roads, Virginia (USA), on 30 October 1937.

The Battle of Midway in June 1942 is famous for a number of reasons. Perhaps chief among them is the sinking of four Imperial Japanese Navy aircraft carriers – the AkagiKagaSōryū, and Hiryū – which turned the tide of the Pacific Theater of Operations in World War II. There is also the way the battle clearly established that carrier-borne aircraft had replaced “capitals ships,” i.e. battleships, as the predominant weapons system of naval warfare. 

What is not as well known is the role that submarines played in this epic battle. On the American side, the USS Nautilus played an inadvertent role in the detection of the IJN carrier fleet. Meanwhile, the greatest damage inflicted by the IJN during Midway was by a submarine, the I-168, which sank the carrier USS Yorktown (CV-5) and the destroyer USS Hammann (DD-412). 

Not U-Boats, But I-Boats

The I-boats were the full-sized submarines of the IJN fleet (meaning they displaced at least 1,000 pounds). The designation does not correspond to the U-boat (Unterseeboot) designation of the German Kriesgsmarine, Rather, it was the transliteration of a character that signified the first in a series, stemming from the 11th century poem Iroha that was used to designate the alphabetical order of Japanese characters, or kana. “I” signified the largest or first class of submarine, followed by the 500-to-999-ton Class B “Ro” boats, and lastly the Class C “Ha” boats, the midget subs with a displacement of less than 500 tons. 

Submarine duty was a highly desirable posting in the IJN, especially for enlisted sailors. Reason being, as noted by Keith Wheeler in his excellent book War Under the Pacific (part of the Time-Life Books WWII series), the brutal discipline for which the Imperial Japanese military was infamous was not as rigidly enforced on submarine crews, thus allowing for a more relaxed work environment that fostered a more genuine sense of camaraderie. How brutal was IJN discipline, you may ask? In the WWII Japanese military, a commissioned officer could strike an enlisted man at any time and for any damn reason. As noted by WWII historian Robert M. Citino:

You could be pummeled nearly to death for almost any reason: failing to salute smartly enough, missing a button on your shirt, a lackadaisical attitude. Failure to snap to attention at the mention of the emperor’s name was a serious offense in this world, and some particularly sadistic officers seemed to delight in mentioning the emperor solely to catch their men napping.”

The I-168 had her keel laid on June 18, 1931, was launched on June 26, 1933, and commissioned on July 31, 1934. She was then decommissioned on Dec. 12 1938, and recommissioned on May 1, 1939. She had a length of 322 feet, a surfaced speed of 23 knots, and a submerged speed of 8.2 knots. Being one of the Kadai-class boats, I-168 wielded six torpedo tubes — four fore and two aft – a 10cm/50 Type 88 deck gun, and a 13.2mm machine gun for AA protection.

During the Battle of Midway, I-168 was skippered by Lt. Comm. Yahachi Tanabe.

Mission at Midway

Of course, the Japanese sub’s sinking of the Yorktown wasn’t a solo act. The historic and beloved carrier under the command of Capt. Elliott Buckmaster had already been severely damaged by Aichi D3A1 “Val” dive bombers and Nakajima B5N “Kate” torpedo bombers launched from the deck of the Hiryū. Mind you, this was after Yorktown had undergone a near-miraculous repair job after the damage she sustained during the Battle of the Coral Sea the month prior. Yorktown was under tow by the fleet tug USS Vireo, and the Hammann had tied up along the carrier’s starboard side to provide firefighting and salvage assistance. Thus was the stage set for a double-tragedy for the U.S. Navy and a double-triumph for the IJN. (Although obviously the sub’s triumph would pale in comparison to the overall defeat Japan suffered in the battle.)

At 1:30 p.m. on June 5, 1942, Tanabe fired a salvo of four torpedoes. The first torpedo struck Hammann, which sank a mere four minutes later. Eighty-one members of the destroyer’s 241 crew perished, a death toll that might have been lower had it not been for the secondary explosions from the ship’s depth charges. The second and third torpedoes struck Yorktown on her starboard side below her bridge, while the fourth tin fish missed astern. 

Tanabe dove his boat to 200 feet to brace for a retaliatory depth charge attack from the surviving destroyers. Over a 64-minute span, I-168 endured 40 depth charges that inflicted severe damage, but the sub was eventually able to safely return to base at Yokosuka

Meanwhile, at 7:01 a.m. on June 7, Yorktown finally sank, with a total of 141 of her officers and enlisted men killed in action. It is said that all surviving USN ships present to witness the sinking lowered their flags to half-mast in salute, and all hands who were topside stood at attention with heads uncovered, many with tears in their eyes.

Midway Maritime Memorials 

The U.S. Navy finally claimed revenge against the I-168 on July 27, 1943, when one of America’s own subs, the USS Scamp, sank her in the Bismarck Sea — 60 nautical miles off New Hanover Island — with a salvo of four torpedoes. All 97 men aboard the Japanese sub perished. To the best of my knowledge, the wreck of the vessel has not yet been found. (If any of our readers know otherwise, please post in our comments section!)

USS Yorktown lies 5,500 meters beneath the surface. The remains of this grand old lady were discovered on May 19, 1998, by Dr. Robert D. Ballard, who of course is most famous for finding the wreck of the RMS Titanic. Meanwhile, Hammann‘s wreck has not yet been found, but presumably it should lie in the same general area as Yorktown.

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). 

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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).