Type A Ko-hyoteki (甲標的甲型) Target “A” Midget Submarines and the Attack on Pearl Harbor

The Japanese Ko-hyoteki midget submarines were used in several theaters of the Pacific War, but their first and most famous use was during the attack of Pearl Harbor on 07DEC41.  They were 80 feet in length.  They were powered by a 600 horsepower (447 kW) electric motor, which could drive them at a maximum speed of 23 knots (43 km/h) or for 100 nautical miles (190 km) at a low speed.  They carried a crew of two and two torpedoes, which were loaded externally from the bow.

For the Pearl Harbor raid they were carried piggy-back by five I-16 class fleet submarines and launched outside the harbor entrance.  The minisubs were launched during the night before the raid, with orders to penetrate the harbor and attack.  Nominally they were to rendezvous with their parent submarines after completing their missions, but the crews were under no delusions of the likelihood for successfully completing this phase and expected not to return.

The actions of the midget submarines are listed below in order of their parent subs.  “I-16-tou” means “I-16’s boat”. There are some loose ends remaining.  The Light Cruiser USS St. Lewis (CL-49) reported being missed by two torpedoes outside the harbor entrance at 1004.  The Japanese fleet submarines were not positioned there so if the report is accurate, it is possible these were fired by I-16-tou.  Alternatively, many believe a photograph taken of Battleship Row during the attack shows a midget sub broaching after firing her torpedoes.  In either case, it is likely that I-16-tou ended up in the West Loch at the end of her mission and her wreckage was dumped off the harbor entrance in 1944.

Individual details:

I-16-tou, ENS Masaharu Yokoyama and PO2c Tei Uyeda, launched at 0042.  Likely penetrated Pearl Harbor, skuttled in the West Lock.  Many believe a photograph taken by a Japanese aviator during the attack shows I-16-tou firing torpedoes at the USS West Virginia (BB-48) and USS Oklahoma (BB-37).  Three messages were received from I-16-tou confirming a successful air attack, claiming that she had damaged U.S. warship(s), and a final message received at 0051 local time on 08DEC41 reporting that the submarine was unable to navigate.  Her wreck was discovered in three sections in the debris field of the West Lock disaster, dumped outside the harbor during the clean-up.  Torpedoes fired, scuttling charge detonated, crew unaccounted for.

I-18-tou, LTJG Shigemi Furuno and PO1c Shigenori Yokoyama, launched at 0215.  Found outside of Pearl Harbor, East of the entrance, recovered by USS Current (ARS-22) on 13JUL60 from depth of 76 feet.  Damaged by depth charges, abandoned by her crew, torpedoes were not fired.  Currently on display at Eta Jima, Japan.

I-20-tou, ENS Akira Hiroo and PO2c Yoshio Katayama, launched at 0257.  Sunk by the Destroyer USS Ward (DD-139) at 0645.  The crew died in the attack, her torpedoes not fired.  Found on the sea floor in 1,312 feet of water by a University of Hawaii submarine in August 2002.  Declared a war grave.

I-22-tou, LT Naoji Iwasa and Petty Officer 1c Naokichi Sasaki, launched at 0116, penetrated Pearl Harbor.  Fired one torpedo at the Seaplane Tender USS Curtiss (AV-4) and one torpedo at the Destroyer USS Monaghan (DD-354).  I-22-tou was struck by shellfire from Curtiss at 0840, then rammed and depth-charged by Monaghan.  Crew was killed in the attack.  Her wreck was recovered on 21DEC41 and used as fill during construction, remains of the crew still aboard.  LT Iwasa’s shoulder insignia was recovered from the wreckage confirming the identification, as he was the only full Lieutenant among the crews.  The insignia is currently on display at Yasukuni.

I-24-tou, Ha-19, ENS Kazuo Sakamaki and CWO Kiyoshi Inagaki, launched at 0333.  She had a faulty gyrocompass which delayed her launch.  She was depth charged twice off the entrance to Pearl Harbor and ran aground.  Broke free and proceeded east, then ran aground again off Bellows Field.  Submarine broke free during air attack and hauled ashore by U.S. forces.  Torpedoes not fired due to damage, scuttling charge failed to detonate.  Inagaki killed, Sakamaki taken prisoner.  Ha-19 was salvaged and went on a War Bond tour, and is currently displayed at The National Museum of the Pacific War in Fredericksburg, Texas.

The Ko-hyoteki crews were deified after the raid. Based mainly on the radio report from I-16-tou, the Japanese believed that the midget submarines penetrated Pearl Harbor and that at lease one had attacked successfully. Missing from the portrait is ENS Sakamaki, who was captured.

A photograph of Battleship Row taken from a Japanese B5N2 “Kate” during the attack. In the center, both West Virginia and Oklahoma can be seen after taking torpedo hits and beginning to list, with oil slicks forming on the water.

A tighter expansion of the previous photograph. The disturbance in the water to the left has been interpreted as the I-16-tou breaching after firing her torpedoes. The three sprays to the left of her conning tower are water being thrown up by her screw, and two torpedo wakes are visible originating from that point. Just to the right of the submarine is a small boat. The interpretation of this photograph remains controversial.

The West Lock Disaster occurred on 21MAY44, when an accidental explosion spread through amphibious assault ships loading ammunition prior to the Marianas invasion. The explosions sank six LSTs and killed 163 sailors. The accident was hushed up and remained classified until 1960.

Debris from the West Lock Disaster were quickly cleared away and dumped off the entrance to Pearl Harbor. Among the debris lie the remains of I-16-kou, broken into three sections. In places the hull is pierced and cables have been threaded through the holes so the sections could be hoisted, visible to the left in this photograph. The bow section has empty torpedo tubes and the unique “figure 8” cable cutter fitted to the Pearl Harbor attackers.

I-18-tou was discovered by U.S. Navy divers outside of the harbor to the east of the entrance. Her torpedoes remained in their tubes, her hatch had been opened and there was no trace of her crew. Submarine contacts were reported off the harbor entrance throughout the morning and many were depth charged (the USS Ward attacked four separate contacts). I-18-tou showed damage from depth charging, perhaps she was another of Ward’s victims?

There can be no question about this one. This is the I-20-tou resting on the sea floor, the hole from Ward’s #3 4-inch gun clearly visible at the base of her sail.

This is I-22-tou. She penetrated the harbor and worked her way around to the west side of Ford Island. There she was engaged by the USS Curtiss and USS Monaghan. She fired a torpedo at each ship but missed. Her hull shows the “washboard” effect of Monaghan’s depth charges and her hull is broken from being rammed and rolled under the destroyer. She was recovered two weeks after the raid.

I-24-tou was plagued by misfortune. The last midget sub to be launched because of trouble with her gyrocompass, she ran up on a reef outside the harbor. After working free she was depth charged and her crew disoriented. She worked around Oahu to the east until she hung up on another reef. Her crew exhausted and overcome by fumes, they abandoned ship after the scuttling charge failed to ignite. ENS Kazuo Sakamaki made it to the beach to become PoW #1, CWO Kiyoshi Inagaki drowned. I-24-tou is seen after being hauled up onto the beach off Bellows Field.

The control station of I-24-tou. Behind the ship’s wheel a man has his hand on the faulty gyrocompass. Reportedly it began to work properly after it was hit firmly.

One of the items recovered from I-24-tou was a detailed map of Pearl Harbor, the entrance is at the bottom. Mooring positions and target ships are indicated. Also note that courses and turning times have been annotated to assist navigation. The Imperial Japanese Navy had spies who provided detailed observations of the harbor prior to the raid, proof such as this only fueled suspicions concerning the Japanese population on Oahu.

The I-24-tou was shipped to the mainland for use in War Bond drives. She is seen here being inspected by shipyard workers in California.

USS Ward (DD-139 / APD-16)

The USS Ward (DD-139) was a Wickes-class destroyer, one of 273 “flush deck” or “four-piper” destroyers built for the United States Navy in WWI.  She was constructed in record time using a construction technique which would later be called “pre-fabrication”.  Her keel was laid on 15MAY18 and she was launched on 01JUN18 – a mere 17 1/2 days.

Here is Ward alongside at the Mare Island Shipyard.  Ward was commissioned into the US Navy on 24JUL18.  During her sea trials she made an impressive 37 1/2 knots.

A nice view of Ward underway in her WWI dazzle camouflage.  If you look closely you can make out her hull number 139 painted under the bridgewing at the deck line. (Naval History and Heritage Command Photograph)

A good view of the port side showing the WWI camouflage pattern.  Wickes class destroyers were armed with four 4″/50 guns, twelve torpedo tubes, and depth charges for anti-submarine work.  Note that the after 4″ gun is mounted on the main deck, later this gun was moved to the top of the after deckhouse.  Ward was decommissioned and place into reserve on 21JUL21, and recommissioned out of reserve on 13FEB41.

The USS Ward is most famous for firing the first shot of the US involvement in the Second World War.  Ward was patrolling the approaches to Pearl Harbor when she received a report from the USS Condor (AMC-14) that a periscope had been sighted in the area.  Ward found the submarine attempting to follow the USS Antares (AKS-3) into the harbor.  The submarine was a Japanese “Target A” mini sub, one of five launched as part of the Pearl Harbor attack.  Ward engaged the submarine and claimed it as destroyed.  Her Commanding Officer, LT William W. Outerbridge reported,  “We have attacked, fired upon, and dropped depth charges upon submarine operating in defensive sea area.”  This was 70 minutes before the first Japanese aircraft arrived over Hawaii.  (Painting by Tom Freeman)

A publicity photograph of Ward’s No. 3 gun crew.  The first shot from No. 1 gun missed but the second shot from No. 3, fired at minimum range, was seen to hit the submarine’s sail.  Most of the crew of the Ward were reservists from Minneapolis, Minnesota.  Ward’s No. 3 gun is preserved today in the courtyard at Minnesota’s state capitol building in  St. Paul.  (US Navy Photograph)

Some skeptics doubted the Ward’s claim.  Those doubts were put to rest on 28AUG02 when researchers from the Hawaii Undersea Research Laboratory discovered the Japanese mini sub on the seafloor within four miles of the entrance to Pearl Harbor in 1,200 feet of water.  The hole made by Ward’s 4″ projectile is clearly visible at the center of the base of the sail – a perfect shot.

The “four pipers” were obsolete as fleet destroyers by the standards of WWII and many were converted to other roles such as seaplane tenders, convoy escorts, minelayers, minesweepers, or fast transports.  Ward was one of 32 flush deckers converted to the fast transport role and was reclassified as APD-16 in FEB43.  In this new configuration she could land 120 troops along with small vehicles using four LCP(R) landing craft.  The 4″/50 guns were replaced by 3″/50 dual-purpose guns and augmented with five 20mm cannon.  Ward lost her torpedo tubes but retained her depth charges which allowed her to still function as an escort.

Ward participated in frequent landing operations both large and small during the better part of 1943/44.  Typically the APDs would land their troops and then provide anti-aircraft and anti-submarine protection of the landing area, and be on-call for Naval Gunfire Support of the troops ashore.  They were also useful for hauling and landing supplies.

On 07DEC44 – exactly three years after the Pearl Harbor raid, Ward landed 108 Army troops at Ormoc Bay, Philippines and was providing ASW screening of the landing area when she was attacked by three Mitsubishi G4M “Betty” bombers.  Two attempted kamikaze runs but missed, the third struck Ward squarely amidships on the Port side. (Naval History and Heritage Command Photograph)

Ward lost power and was unable to control her fires.  Here the destroyer USS O’Brien (DD 725) moves in to assist the stricken Ward. (US Navy Photograph)

O’Brien is alongside with her firehoses at work.  Even with her assistance it was clear that the fires were uncontrollable and the Ward was doomed.  Less than half an hour after the kamikaze hit her Captain, LT Richard E. Farwell, ordered abandon ship.  O’Brien and other vessels took aboard Ward’s crew, then O’Brien moved off 800 yards to sink Ward with gunfire.  Her first salvo detonated Ward’s after magazine.  When the smoke cleared, Ward was slipping beneath the surface stern first.

In a strange twist of fate, the Captain of the O’Brien that day was William W. Outerbridge, now a Commander.  He was the Captain of the USS Ward during the attack on Pearl Harbor, and commanded the destroyer which sank her exactly three years to the day later.  O’Brien was later hit by a kamikaze herself off Okinawa and was damaged.  Outerbridge survived the war, among his decorations was a Navy Cross for Ward’s actions off Pearl Harbor, and a Purple Heart earned at Okinawa. (US Navy Photograph)