I-176: The Only IJN Submarine to Sink a USN Submarine


There are a number of instances in World War II that saw submarines sink other submarines. That said, submarine versus submarine duels was not very common, and there was only one instance where both submarines were submerged and one was sunk (HMS Venturer sinking U-864). In the Pacific Theater, while Imperial Japanese Navy (IJN) submarines did carry out several successful attacks against Allied warships (being ordered to prioritize warships over merchant ships, unlike the U.S. Navy), the Japanese submarine force generally put in a pretty meager performance considering the impressive characteristics of some of their boats. Despite having many unique types of submarines, the entirety of the Pacific War only saw one specific instance of an IJN submarine sinking a USN submarine. This occurred in November 1943 between the Japanese submarine, I-176, and the American submarine, USS Corvina.

The Boats

I-176: KD7-Type submarine

I-176 was a KD7-type submarine. She was laid down on 22 June 1940 and launched on 7 June 1941. On 20 May 1942, she was renumbered from I-76 to I-176 and commissioned on 4 August 1942.1

The KD7-type submarines were the largest single class of the kaidai type (fleet type) submarines in the IJN, with 10 boats constructed in total. Several of these boats, including I-176, I-177, and I-181 were converted for cargo duty early on in their careers. Indeed, these boats spent most of their operational careers doing supply runs to isolated island garrisons in the Pacific.2

Drawing of Kaidai Type 7 (KD7) submarine circa 1942.3

Mark Stille writes that the KD7-type boats represented Imperial Japan’s gross misuse of its submarine force. Seven out of the ten boats were sunk within their first year of service and the remaining ones had difficulty in conducting successful attacks due to advances in U.S. antisubmarine weapons and tactics. I-176 was the most successful boat of the class; however, by October 1944, with the loss of I-177, the entire class was removed from the IJN’s order of battle.4

USS Corvina (SS-226): Gato-class submarine

USS Corvina being launched in May 1943.
Profile drawing of Gato-class submarines in original and late-war configurations.5

The USS Corvina (SS-226) was a Gato-class fleet boat built by Electric Boat Company. Her keel was laid on 21 September 1942, she was launched on 9 May 1943, and commissioned on 6 August 1943.6 Her builder actually set a record for the shortest construction time for a submarine from her keel laying to her commissioning of 317 days.7

Mark Stille writes that the Gato-class incorporated a number of improvements that began with the Dolphin-class boats. Aside from some small improvements and the lengthening of the hull by 5 feet to allow for further engine room compartmentalization, the Gato-class boats were essentially repeats of the previous Tambor-class. A total of 77 boats were completed and 20 were ultimately lost to enemy action.8

At the time of Corvina‘s commissioning, it was decided to open up a second front against the Japanese following the success of operations in the Solomons. The Gilberts were chosen as they offered a direct line of communication from the south, had airfields that would be useful for fighter aircraft, and were less well-defended than the Marshalls. The invasions of Tarawa (Operation Galvanic), Makin (Operation Kourbash), and Apamama (Operation Boxcloth) were set for 20 November 1943. Task Force 53 was sent to land the 2nd Marine Division on Tarawa, and the Corvina, along with nine other submarines, was to provide support.9

After three weeks of training, Corvina left Oahu on 4 November 1943 for her first war patrol with Commander Roderick S. Rooney in command. She was to proceed to the waters south of Truk, along with the submarines Thresher (SS-200), Apogon (SS-308), Blackfish (SS-221), and Drum (SS-228), with orders to interdict any enemy reinforcements or warships that might sortie from Truk in response to the Tarawa landings. Corvina refueled at Johnston atoll on 6 November and continued to Truk. She was never heard from again.10

The Sinking of the Corvina – 16 November 1943

Corroborating evidence strongly suggests that Corvina was sunk by a Japanese submarine. According to Japanese naval records captured in 1946, the Japanese submarine I-176, under the command of Lieutenant Commander Yamaguchi Kozaburo, was ordered to Truk in November 1943. Ultra (Allied signals intelligence) intercepted the orders for I-176 and naval intelligence sent a message to Corvina, Drum, and Blackfin, warning them of an enemy submarine in their patrol area. A message from I-176 was also intercepted stating, “Received direct torpedo hit en route to Truk, no damage.” Presumably, I-176 was hit by a defective torpedo from a U.S. submarine.11 Although, exactly which submarine fired the defective torpedo that hit I-176 is unknown if that is indeed what happened.

On 16 November, I-176 was cruising north partially submerged at 16 knots about 300 miles south of Truk. At 2312 lookouts spotted a dark object, illuminated by the moonlight, to the northeast at a distance of about 8,800 yards and Lieutenant Commander Yamaguchi ordered the submarine to dive and turn towards the target. Four minutes later, they (mistakenly) identified the target as a Perch-class submarine, likely in the process of recharging its batteries. I-176 then crash-dived and went to silent running until they reached a position off Corvina‘s starboard quarter about 2,700 yards away. By then it was 0057 on 17 November. Considering the firing angle to be too excessive, Yamaguchi ordered his boat to battle-surface in fifteen minutes. However, before that could happen, at 0112, Corvina turned towards I-176 whereupon Yamaguchi belayed the order to surface and instead turned the boat to the right to keep the Corvina on his port beam. At 0120, I-176 fired three torpedoes from her bow tubes at the Corvina, and 25 seconds later, two explosions were heard that shook I-176 considerably given her proximity to the target. At 0130 Yamaguchi performed a periscope search and then surfaced the boat. Searching around the site of the attack, an oil slick and various pieces of debris were spotted. Convinced that he had hit his target, Yamaguchi set a course to Truk and arrived on the 18th to a hero’s welcome where the crew was invited to dine with the Commander-in-Chief of the 6th Fleet. As for Corvina, she was reported as presumed lost on 23 December 1943, after failing to respond to various orders and messages. She was lost with all 82 hands, and her loss was announced on 14 March 1944.12

We will never know exactly what happened aboard the Corvina during her last moments. Did her crew spot I-176 and that is why Corvina turned towards her? Did they even have a shot at sinking I-176? Why did Yamaguchi turn to keep the Corvina on his port beam, and did I-176 fire her torpedoes from that position?* The list of questions goes on and on. For whatever reason, despite receiving a warning of an enemy submarine in their patrol area, Corvina got ambushed and sunk by I-176.

*Note: The positions and orientations of the two submarines during the attack is a bit confusing based on the limited information from the sources. I am no submariner, but I can only conjecture that Yamaguchi wanted to keep a certain distance between his boat and Corvina which is why he turned to the right to keep her on his port beam at around 0112. Still, if Corvina had turned directly towards I-176 and was closing the distance, then such a turn would have presented I-176 as a larger target for the Corvina. The KD7 boats have no stern tubes, so they could not have fired at Corvina while running away. Thus, I-176 may have had to maneuver again to fire her bow tubes at Corvina, but no mention is made of any further maneuvers either submarine was doing at this time.

The Fate of I-176


The loss of the USS Corvina would not be in vain, and the U.S. Navy would ultimately get its vengeance six months later.

I-176 returned to Kure, Japan on 26 November 1943 to undergo an overhaul. On 1 February 1944, she received a new CO, Lieutenant Commander Okada Hideo. During the month of March, she ran a supply mission to Mili in the Marshall Islands and later returned to Truk in April. On 10 May, she received orders to leave Truk to resupply Buka Island. On 12 May, while north of Buka, she was spotted by an American patrol plane which signaled her position to DesDiv 94 in the Treasury Islands. DesDiv 94 included the destroyers USS Franks, USS Haggard, USS Hailey, and USS Johnston.13

Four days later (16 May), I-176 was 135 miles east by north of Green Island when DesDiv94 located her. At 2145, Haggard made sonar contact with a submarine (I-176) off her starboard bow at 2,800 yards distant. Haggard and Franks made five separate attacks after 2213, one of which saw Haggard being slightly damaged by exploding depth charges. Between the last two attacks, the destroyers detected a heavy underwater ripple explosion. At 0015 the following day (17 May), Franks dropped a pattern of 13 depth charges whereupon a seven-mile-long oil slick and various pieces of debris, including pieces of cork, sandalwood, and a geta sandal, were spotted on the surface. The attack was initially assessed as a probable kill. I-176 was listed as presumed lost with all 103 hands on 11 June 1944, and she was removed from the Navy List on 10 July 1944.14


In the end, this particularly one-sided submarine battle went down in history as the only time an Imperial Japanese Navy submarine sank a U.S. Navy submarine. It stands as something of a fluke in Imperial Japanese Naval history given the less-than-stellar performance of their submarines. It seems that I-176 just got lucky.


1. Bob Hackett and Sander Kingsepp, IJN Submarine I-176: Tabular Record of Movement, last modified November 1, 2016, http://www.combinedfleet.com/I-176.htm.

2. Mark Stille, The Imperial Japanese Navy in the Pacific War (Oxford, UK: Osprey, 2013), 341 – 342.

3. Hansgeorg Jentschura, Dieter Jung, and Peter Mickel, Warships of the Imperial Japanese Navy, 1869-1945 (Annapolis, MD: Naval Institute Press, 1982), 173.

4. Stille, The Imperial Japanese Navy in the Pacific War, 342.

5. John Alden, The Fleet Submarine in the U.S. Navy (Annapolis, MD: Naval Institute Press, 1979), 277.

6. Alden, 254.

7. Alden, 78.

8. Mark Stille, The United States Navy in World War II: From Pearl Harbor to Okinawa (Oxford, UK: Osprey, 2021), 266.

9. Guy Nasuti, “Corvina (SS-226).” DANFS, U.S. Naval History and Heritage Command, June 26, 2018. https://www.history.navy.mil/research/histories/ship-histories/danfs/c/corvina.html. From the online Dictionary of American Naval Fighting Ships. Hereafter referred to as DANFS.

10. Nasuti, DANFS.

11. Nasuti, DANFS.

12. Nasuti, DANFS.

13. Hackett and Kingsepp, IJN Submarine I-176.

14. Hackett and Kingsepp, IJN Submarine I-176.


Alden, John. The Fleet Submarine in the U.S. Navy. Annapolis, MD: Naval Institute Press, 1979.

Hackett, Bob and Sander Kingsepp. IJN Submarine I-176: Tabular Record of Movement. Last modified November 1, 2016. http://www.combinedfleet.com/I-176.htm.

Jentschura, Hansgeorg, Dieter Jung, and Peter Mickel. Warships of the Imperial Japanese Navy, 1869-1945. Annapolis, MD: Naval Institute Press, 1982.

Nasuti, Guy. “Corvina (SS-226).” DANFS, U.S. Naval History and Heritage Command, June 26, 2018. https://www.history.navy.mil/research/histories/ship-histories/danfs/c/corvina.html.

Stille, Mark. The Imperial Japanese Navy in the Pacific War. Oxford, UK: Osprey, 2013.

Stille, Mark. The United States Navy in World War II: From Pearl Harbor to Okinawa. Oxford, UK: Osprey, 2021.


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