The Taiho Lesson

Written by B.D. Ingram

The best technology and engineering are of no use if no one has the will or the training to use it.  

    During the 1930s, the Imperial Japanese Navy embarked on a series of major shipbuilding campaigns to bring the fleet up to parity with the United States Navy. The first two of these plans (the 1st and 2nd Naval Armaments Supplement Programs) were under the restrictions of the London Naval Treaty of 1930, and the ships that resulted from them had several serious failings because of their light construction and heavy armaments. In 1936 Japan was done with treaties, after walking out of the negotiations for the Second London Naval Treaty they set to work on a new and even more extensive naval building program.

    The 3rd Naval Armament Supplement Program of 1937 was massive, calling for the construction of 66 new warships and 14 more naval air groups. The warships included the battleships Yamato and Musashi, the largest battleships in the world, and the two new large fleet aircraft carriers Shokaku and Zuikaku. 

Development History, and Design Details

    In 1938, in response to the Japanese invasion of China and the German annexation of Austria, the United States Congress passed the Naval Act of 1938, also known as the Second Vinson Act. This was a massive construction program with the intention of increasing the strength of the US Navy by 20%. Overall, this act authorized the construction of 105,000 tons of new battleships, 68,754 tons of new cruisers, 40,000 tons of new aircraft carriers, 38,000 tons of new destroyers, and 13,650 tons of new submarines.

    Reacting quickly, the Japanese authorized the 4th Naval Armament Supplement Program in 1939, this was even larger than the 3rd Program from 1937. This program included 80 warships, including such ships as the 3rd Yamato class battleship Shinano, the prototype fast (40 knot) destroyer Shimakaze, seven cruisers, 43 destroyers, more than 50 submarines, dozens of minelayers and minesweepers, several support ships, and the most advanced Japanese aircraft carrier of the time, Number 130, later named Taiho. 

    The Taiho (Magnificent Phoenix) was a departure from previous Japanese designs, being much more heavily armored than previous ships. This was to allow the ship to safely operate closer to the enemy so that her aircraft could fully exploit their maximum payloads. But this came at the risk of taking damage that would render existing aircraft carriers unusable, thus the armor on the flight deck and around the ship's vital areas.

    During the design and development, Taiho's displacement crept up from 33,800 to 34,200 tons due to additional AA guns and firefighting equipment that was added.

    To keep the center of gravity lower, Taiho had one less deck than the preceding Zuikaku class, and a lower freeboard (the area between the waterline and the deck). To help keep the ship seaworthy, Taiho was built with a fully enclosed hurricane bow similar to the HMS Illustrious.

    Taiho had a large flight deck, 257.5 meters [845 feet] long, and varying between 18 to 30 meters wide [18 at the bow, 30 amidships, 29 around the island, and 27 at the stern]. The armor on the flight deck was made of two layers, the upper being 75 mm thick [~3 inches], and the lower being 20 mm. This was projected to be able to stop 500-kilogram bombs from dive bombers. Instead of wood, the deck was covered with a material derived from latex.

Taiho in the foreground, Shokaku is the carrier in the background.

    It was originally intended for there to be a propeller wash deflector in front of the forward elevator, and to install catapults to launch aircraft. But to simplify construction and because none were available (respectively), they were not on Taiho when she was finally completed. Similarly, the 14 sets of arresting wires were downgraded from the originally planned Kure Type 10 to the Kusho Type 4. There were also three sets of crash barriers of the Kusho type.  

    There were only two aircraft elevators on Taiho, which were smaller than the Zuikaku class, but they were armored with two layers of 25mm thick steel and each weighed around 100 tons. They were supposed to be protected against 500 Kg bombs from dive bombers.

    The island incorporated the 17-meter high funnel, which was tilted out by 26 degrees. Many other IJN carriers had their funnels pointed down towards the ocean, clearing space on the flight deck and making it easier to land on the ship. But Taiho's lower design made positioning the funnel off to the side a risk in the event of heavy seas or a major list. This design of funnel and island was also used on the two ships of the Hiyō class.

    The island also carried one of Taiho's Type 21 air-search RADAR sets, with the second being located behind it. Two Type 94 AA directors were also mounted forward of the island on the starboard side. The compass bridge was protected from splinters from shells and bombs by 25 mm [1 inch] of armor, the upper part of which was an air defense station. The steering room was inside a 40 mm thick steel cylinder, able to protect it from American 6'' (152mm) shell fire.

    For more proactive protection against aircraft, Taiho was armed with twelve of the excellent 100mm/65 Type 98 guns. These were in six dual mountings, three on each side of the ship. These were one of the best AA weapons that the Japanese fielded in the war. There originally were plans to mount twenty-four 25mm AA guns in eight triple mounts, but as experience was gained in the war, that number went up to seventeen triple mounts. With eight directors for them mounted on sponsons. 

100mm/65 emplacement on Balikpapan, Borneo

A triple 25mm gun mounting, captured on Guadalcanal

    Like many other Japanese aircraft carriers, Taiho had upper (18 meters wide) and lower (17 meters wide) hanger decks. From experience in the war, the hanger decks were well equipped to handle battle damage and fire. Fireproof curtains could divide the upper hanger into five sections and the lower into four. The supports for the flight deck in the upper hanger were armored as well to reduce or prevent damage from in-hanger explosions. The sides of the hangers also had 1.5 x .7 meter openings to vent the force from blasts out of the ship. These were covered in 25mm armored shutters, the same thickness as the armor over the rest of the sides.

    The lower hanger deck floor was made of 16mm steel to protect repair shops and other critical areas. There was additional armor over machinery and magazines, both vertical and horizontal. The engine rooms and tanks of aviation gas were armored to be safe from 800 Kg AP bombs dropped from 3,000 meters [9,800 feet]. Bomb and antiaircraft magazines were supposed to be safe from 1,000 Kg bombs dropped from the same altitude. This came out to a 75mm [3 inch] thick armored deck over all of the magazines.

    The horizontal armor for the magazines was calculated to protect against 8 inch (203mm) AP shells fired from as close as 12,000 meters [13,100 yards]. This meant that every magazine was protected by 165mm of armor. The machinery areas and tanks of aviation fuel were armored against 6 inch shellfire as well. 

    Six-inch guns were the largest guns allowed for light cruisers, such as the American Brooklyn and Cleveland classes. 
    The hanger decks were equipped with an advanced firefighting system, having a fairly typical CO2 system like on many other Japanese aircraft carriers, and a more advanced foam (soap and water based) suppression system in addition to the firewalls. The CO2 being heavier than air would sink down through the ship and displace oxygen, extinguishing fires but also running the risk of asphyxiating any unfortunate crew at the bottom of the ship. The foam system was able to create a blanket over aircraft and any combustible materials on the hangar decks to prevent fires from spreading and potentially being able to suppress them entirely. 

    

    The area below the waterline is where some weaknesses show themselves.

    The underwater protection was indented to resist 300 Kg [~660 lb] explosive charges. There were two 22 mm [~.87 inch] thick torpedo bulkheads three meters [9.8 feet] inside the outer hull plating, located amidships to protect vital areas. Avgas tanks were surrounded by an air gap and one-meter wide tanks of fuel oil. Then the bulkheads that separated the machinery spaces were armored, giving up to five layers of protection. The bottom of the hull beneath avgas tanks and the magazines was three layers thick as well.

    This can be clearly seen in this cutaway drawing of Taiho, taken from the United States Naval Technical Mission to Japan Report S-06-2.

    But according to that report, the torpedo bulkhead mentioned above did not extend to cover these tanks, only covering the machinery spaces. Kojinsha also seems to suggest that the torpedo bulkhead didn't extend to protect the tanks of oil and aviation fuel forward of the engine spaces.

    The ship's powerplant was eight Kampon RO Go boilers that could produce 160,000 shaft horsepower (120,000 KW), that drove four geared Kampon steam turbines which drove the Taiho's four propeller shafts. Taiho's top speed was 33.3 knots, and she had a range of 19,000 kilometers at 18 knots. This was one knot slower than the Shokaku class but provided a longer range. 

    All of the above was to make clear that Taiho was not a really bad design*. By the standards of the day, many of its features were very well thought out, and based on what is known, there were no glaring defects in the actual construction. All of this makes what happened to the Taiho so baffling and worthy of study.

The Service Career of Taiho, Her Sinking, and a short overview of The Battle of the Philippine Sea

    Taiho was laid down on June 10th, 1941 and launched less than two years later on April 7th, 1943. By then the war had started to turn against the Japanese. At the Battle of Midway in June 1942, the Kido Butai lost four of its best carriers in a single day while the US Navy lost only one. Then came the ongoing attrition of the Solomon Islands campaign that cost them many of their best and brightest pilots as the Japanese contested the invasion of Guadalcanal on land, sea, and air.  
    Taiho wasn't completed and commissioned until March 7th, 1944. By then the Japanese were definitely on the back foot, with the best of their naval aviation corps dead, most of their fleet carriers lost along with large numbers of other warships, and was under constant pressure from the ever-growing United States Navy.

    On June 19th, 1944, three months after Taiho was commissioned, the Imperial Japanese Navy engaged the US Navy at the Battle of the Philippine Sea. The American objective was to capture the Marianas Islands (Operation Forager), to provide a base from which to assault the Philippines, eliminate Japanese bases in the central Pacific, and to secure bases from which B-29 Superfortress heavy bombers could reach the home islands of Japan. 

    The 19th of June was a week after the bombardment had begun on the island of Saipan, and four days after Marines had landed. For 24 days the Marines and the US Army fought the Japanese, suffering about 13,800 casualties (3,426 killed or missing, 10,364 wounded) in the effort. The Japanese lost 29,000 military personnel, and tragically thousands of Japanese civilians who were killed in the fighting or committed suicide out of terror of the Americans. 

   

    But on the 19th, that was all in the future, and the positioning of the US navy provided an opportunity for a plan known as A-Go. A-Go was only slightly changed from an earlier Japanese plan called Operation Z, the plans of which had been captured earlier in 1944. 

    Overall A-Go and Operation Z before it were plans for using the land based aircraft in the Marianas and the remaining Japanese carrier force to conduct massive strikes on the US Navy. This was part of the Japanese notion of Kantai Kessen, or the Decisive Battle, the one climactic fight that would break the ability of the United States to continue the war. 

    For the operation, the Japanese committed nearly everything they had as the 1st Mobile Fleet, all under the command of Vice Admiral Jisaburo Ozawa.

Vice Admiral Jisaburo Ozawa 

    'A Force' was commanded personally by Ozawa aboard Taiho. This consisted of Carrier Division One, Taiho, Shokaku, and Zuikaku, the latter two carriers being veterans of the Pearl Harbor Raid. The Fifth Cruiser Squadron, with the heavy cruisers Haguro and Myoko under the command of Rear Admiral Shintaro Hashimoto. Lastly was Destroyer Squadron 10 commanded by Rear Admiral Masanori Kimura, with the light cruiser Yahagi and the destroyers Asagumo, Urakaze, Isokaze, Wakatsuki, Hatsuyuki, Akizuki, and Shimotsuki. 

    Air Group 601 was spread over the three carriers, with a total of 79 A6M fighters, 70 D4Ys, 51 B6Ns, and 7 D3As. Sources conflict on the exact number of aircraft carried by each ship, three examples of Taiho's reported air wing are provided below.

    Osprey Campaign 303 - The Philippine Sea - Mark Stille 

            20 A6M5 Zero

            27 D4Y1 Judy, 1 D3A2 Val

            13 B6N1 Jill

            3 D4Y1-C Judy

    NavWeaps Order of Battle - Dan Muir

            26 x A6M5

            23 x D4Y

            17 x B6N

            2 x D3A

    Kojinsha

            27 A6M5

            18 B6N2

            27 D4Y2/3 and D3A2

            3  D4Y1-C

    The quality of the Japanese pilots and aircrew was poor, especially compared to the pilots of the United States Navy. Air Group 601 only had about six months of training, in Carrier Division 3 they had three months, and CarDiv 2's pilots and crew had a scant 100 hours. 

    Due to fuel shortages, and the need to preserve the force against American submarine attack, the carriers were unable to sortie from their bases to conduct proper training exercises. So young pilots couldn't improve, and the skills of more experienced pilots deteriorated. These issues also affected the crews on the carriers who maintained the aircraft, who were also undertrained and lacked practical experience, causing the quality of the aircraft to degrade as well. 

    These issues all came to a head on June 13th, when a B6N Jill crashed while trying to land on Taiho shortly after the fleet departed its base at Tawi Tawi. The Jill struck another aircraft, and when the ensuing fire had been extinguished, two Jills, two Judys, and two Zeros had been destroyed. 

    The battle on the 19th of June 1944 was a bloody disaster for the Japanese. 

    Vice Admiral Kurita's Vanguard Force (C Force) was the first to launch its aircraft against the Americans (Task Force 58, split into four carrier task forces), between 64 and 70 aircraft took off from the light carriers starting at 0830. Designated Raid I by the Americans, this force was mostly comprised of Zeros with bombs, about 16 fighter escorts, and eight Jill torpedo bombers. 

    The American task force detected Raid I at 125 nautical miles, and interceptors were scrambled at 1023 to meet the Japanese force. Instead of pressing their attack, the Japanese force began to orbit about 70 nautical miles away from the Americans to receive orders from their commanders. This took about a quarter of an hour, giving the Americans more time to launch fighters, and to close the distance. 

    Hellcats from the American carriers shattered the Japanese formation, about 40 of them survived the first contact, but they were met by even more fighters as they closed on the American fleet around 1050 hours. Only one of the bomb-armed Zeros scored a direct hit, on the battleship South Dakota. 27 sailors were killed and 24 more were wounded. There were several near misses, and four American pilots were listed as missing in action after the engagement. 

    In the end the survivors of Raid I amounted to eight of escort fighters, 13 of the fighter-bombers, and six of the torpedo bombers. The first Japanese air assault of the day had been comprehensively broken by American fighters. 

Japanese aircraft being shot down as it attempted to attack escort carrier Kitkun Bay, near Marianas Islands, Jun 1944 - Photo from ww2db and the US National Archives

    

    The situation for Raid II, coming off Ozawa's force of carriers, including Taiho, started to deteriorate even faster. At 0856 the force of 128-130 aircraft started to launch, 48 fighters, 53 Judy dive bombers, and 27 Jill torpedo bombers. 

    It was around 0910 that Taiho was hit, which will be detailed further below. Eight of the original 130 aircraft returned with mechanical problems, and then at 1000 hours the remaining aircraft flew over the Van Force. Where they were promptly engaged by the anti-aircraft gunners on those ships, costing two aircraft shot down and another eight that had to return with damage.  

    Raid II was detected around 1110 hours at 115 nautical miles, and they were subject to fighter attack from about 1140 hours at 60 nautical miles out, practically all the way to the American task force. None of the Japanese weapons scored a direct hit. However, the near miss of a bomb and the plane that carried it by USS Bunker Hill killed two men and wounded 72 more, started several fires, ruptured fuel tanks, knocked out an aircraft elevator, and perforated the side of the ship. USS Indiana was also hit on the waterline by a Jill, but it did only minor damage and quickly was lost beneath the sea. 

    It was all over around 1215 hours. Only 31 aircraft from Raid II survived their attacks, 16 fighters, 11 dive bombers, and only four of the torpedo bombers. 

    A handful of minutes later, at 1222 hours, the Japanese carrier Shokaku was hammered by three or four torpedoes from the USS Cavalla. Nearly 60 nautical miles from where Taiho had been hit. These hits  had an immediate and ultimately mortal effect, with massive fires starting in the hangar deck, a list to starboard, and a reduction in speed. The destroyer Urakaze spent the next several hours hunting Cavalla, to no real effect. 

Painting of Shokaku, artist unknown

    She was left behind as Carrier Division 1 turned north, with worsening fires separating the men in the bow from those in the stern of the ship. Despite this, her crew fought hard to save their ship for the entire ordeal. Approximately at 1310 hours a bomb in the hangar exploded, sending a series of secondary explosions through the ship.

    Shokaku's strike planes started to return around 1450 hours, but they were directed away from the blazing carrier. Captain Matsubara Hiroshi gives the order to prepare to abandon ship before tying himself to the bridge in order to go down with the ship. 

    Crewmen gathered on the flight deck astern to watch the flag being lowered, before they started to abandon ship. Then a further disaster struck.

    The bow suddenly dropped down, water poured into the open well of the number one elevator, causing a violent shaking and a rapid up-ending of the ship. Hundreds who had been gathered on the flight deck astern were knocked from their feet, slid down the deck into the open pit of elevator three, and into the blazing hangar deck. Survivors and those on other warships reported that Shokaku sank with her stern high, propellers visible. After she was gone from the surface, four large explosions were reported from below.

    1,263 men perished with the ship, 58 officers, 830 petty officers and sailors, 376 members of Air Group 601, and eight civilians. A light cruiser, Yahagi, and two destroyers (including Urakaze) picked survivors out of the water. 570 in total were rescued, including Captain Matsubara, who had been swept out of the bridge as Shokaku sank. 

Shokaku sinking, from John Hamilton's War at Sea. Image file from CombinedFleet.com. 

A more in-depth account of the sinking, including analysis of the actual damage and a more comprehensive timeline, can be found on the Combined Fleet website linked here - The Sinking of Shokaku -- An Analysis

    At 1000 hours Raid III had been launched by Carrier Division 2, Ozawa's 'B' force. 47 aircraft were launched, 15 Zeros, 25 more Zeros with bombs, and seven Jills armed with torpedoes. They were directed to attack an old contact, and then their orders were revised after takeoff to a new target, but that order only reached about half of the aircraft. 27 continued on to an empty patch of ocean, and then returned to their carriers without taking any losses. 

    The other group of 20 planes spotted what they claimed to be two battleships at their new target, but pressed on to find carriers. At 1255 they gave up on carrier hunting and turned back to try at the battleships. 

    Then they were attacked by fighters from USS Yorktown and USS Hornet, seven Japanese aircraft were shot down, and a handful broke through to try and attack the American ships. Only one bomb landed within 600 yards of USS Essex around 1320 hours.

    Overall, Raid III had accomplished nothing of note in terms of damage on the Americans. Though overall forty aircraft of the original 47 returned to their home carriers safely. 

    Ozawa's last attack of the day (Raid IV) was launched at 1100 hours, from Zuikaku and the ships of Carrier Division 2. 82 more aircraft, and just like in Raid III they quickly became split and scattered over a wide area of the Pacific. 

    First directed to a non-existent target, one group headed for Guam, and on the way there Hellcats attacked. 30 of the 49 aircraft were shot down, and the 19 that did manage to touch down on the island were damaged to interoperability, they never flew again. 

    Another group headed for the island of Rota, they spotted the Americans en route, but were detected by radar. However poor weather gave them an opportunity, as the combat air patrol and other intercepting fighters failed to make contact for several minutes, allowing some of the Japanese bombers to reach the carriers without being engaged. 

    Half a dozen Judy dive bombers got to the point of bomb release on USS Wasp before American anti-aircraft guns opened fire at 1423. Quick maneuvering caused all the bombs to miss, and another trio of dive bombers that attacked Wasp and Bunker Hill also failed to connect with their bombs. Only one of these nine total bombers survived. 

    The last actions of Raid IV was the final 18 Japanese aircraft on their way back to their carriers, they ran into a couple of American force of scout aircraft, comprised of Hellcats and Avengers. Half a dozen Japanese aircraft were shot down, but two American planes off Bunker Hill were lost. 

    Nine of the 82 original aircraft returned to the Japanese carriers, and despite one of the best chances of the day, no hits were scored on any American warships. 

A near miss on USS Bunker Hill (CV-17) on June 19th, the Japanese plane that dropped the bomb, minus its tail, is on the left side. Photo taken from USS Monterey (CVL-26) - Photo from NavSource.

   The US Navy had thoroughly carried the day, sinking two aircraft carriers (Shokaku, Taiho), and inflicting a stunning loss of 243 aircraft out of the 373 that had been launched by the Japanese. Also lost were 50 based on Guam, nine that were aboard Shokaku when she was sunk, and 13 aircraft on Taiho. 

    In return, somewhat less than 50 Americans were killed between lost aircraft and crews aboard ships, only one direct hit had been scored on a battleship, and 14 Hellcats were shot down in combat, with another 6 being operational losses due to damage or otherwise. 

    However, the Japanese didn't realize the full extent of the disaster, the few pilots who returned reported that four American aircraft carriers had been sunk, and six others were burning. So Ozawa, having survived the sinking of his flagship, remained in the area to prepair for more attacks the next day after taking on fuel. His facilities abord the heavy cruiser Haguro were lacking, and it took until 1300 hours on June 20th before he reached Zuikaku and discovered the full degree of the losses. 

    His force was down to about 100 aircraft, Carrier Division One, now only Zuikaku, had 32 aircraft. Division Two had 46 spread over its three carriers, and Division Three had 22 left. With the hope of aircraft on Guam still being able to launch attacks, he only delayed his next planned strike until the 21st. 

    But on the 20th of June, the Americans launched their own attacks. Late in the day, American aircraft descended on the Japanese forces. 

Zuikaku and two destroyers at the Battle of the Philippine Sea, Jun 1944. Photo from ww2dbase, and US National Archives

    Overall the results were lacking, 20 American aircraft were lost, half a dozen to anti-aircraft guns and a dozen to Japanese CAP fighters. Bombing and torpedo accuracy was also disappointing, as even though several ships were hit only one carrier was sunk (the converted liner Hiyō). Also a group of American aircraft attacked the Japanese supply group, damaging two oilers so they had to be scuttled, and damaging another that managed to fight the fires and survived.  

    Jun'yō, Ryūhō, Zuikaku, and Chiyoda were all hit but survived with various degrees of damage, six other warships were hit and damaged which degraded their combat capacity to various degrees. 

    Most notably of the 100 Japanese aircraft left on the carriers at the end of the 19th, 65 of them were lost in combat over the Japanese task forces, or were lost for operational reasons on the 20th. 

    

    The nighttime attempt to recover the American strike force nearly turned a disappointing day into a catastrophic one. It was 2045 hours when the first returning aircraft arrived over the fleet. Over the next two hours, 80 aircraft were lost in crashes on landing or had to ditch in the ocean when their fuel ran out. All told the USN lost 100 aircraft, 100 pilots, and 109 aircrew on the 20th, though a several day long search and rescue effort resulted in only 16 pilots and 33 aircrew unaccounted for. 

    

    At 2046, Ozawa received orders to end the operation, and the Japanese forces started to with draw. American scouting efforts to relocate the Japanese fleet, or at least any crippled ships left behind, revealed that the Japanese had managed to slip out of range. The pursuit was abandoned late on the 21st, and the Japanese fleet reached Okinawa late on the 22nd, ending the battle. 

    The Philippine Sea was a crushing defeat for the Imperial Japanese Navy. 

    They had started the battle with nine aircraft carriers, and lost three of them. More than 600 carrier and land-based aircraft, along with hundreds of irreplaceable aircrew had been lost in attacks against the American fleet or in defending the Japanese forces against attack. Also sunk were two oilers, six other warships were damaged, and an estimated 2,987 men were killed. 

    The Japanese carrier air arm, having been painstakingly rebuilt once before after the devastating losses at Midway and in the Solomon Islands, was effectively wiped out for the rest of the war. 

    In return for these catastrophic losses, the US Navy suffered 109 men dead, 123 aircraft of all types destroyed, and one battleship and one aircraft carrier damaged. 

    But amid the destruction, the fate of the Taiho is of special note. 

    A map showing the route of the two fleets. The Japanese plan would have seen their aircraft take off, hit the Americans, land in the Marianas to rearm and refuel, then hit the Americans again on their way back to their carriers.

    The submarine USS Albacore was one of four submarines positioned in a rough square to try and spotA Vice Admiral Ozawa's force of aircraft carriers. On the 18th they had been shifted 100 miles south of their original position based on reports from another submarine, USS Cavalla. 

    At about 0800 hours on the morning of June 19th, Albacore's skipper Jim Blanchard raised his periscope and found himself in the perfect position to engage Ozawa's carriers.  

The USS Albacore (SS-218) on the surface near Groton, Massachusetts in 1942.

    At 0745, Taiho turned into the wind and started to launch her aircraft for the main strike (called Raid II by the United States, Raid I was launched by the Van force of light aircraft carriers) against the American fleet. Albacore closed from 9,000 to 5,300 yards, letting the first Japanese carrier pass by and maneuvering around a destroyer to line up a shot at Taiho. As the aircraft were forming up for their attack, Albacore launched a full spread of six torpedoesB at Taiho from her bow tubes. Due to a torpedo data computer malfunction, Blanchard eyeballed his shots before immediately diving away to evade the escorting Japanese destroyers. 

    Four of the torpedoes missed outright, and while Blanchard thought he'd scored two hits right before the depth charging started, his torpedoes had been spotted by the aircraft launching from Taiho. One of those planes, a Yokosuka D4Y dive bomber, piloted by Warrant Officer Sakio Komatsu, dove for the water. He crashed his aircraft in front of the torpedo, destroying it a mere 100 yards away from the shipC.

    The single remaining torpedo from Albacore hit Taiho on the starboard side, just ahead of the island, in the vicinity of frame member 54 (as can be seen in the USNTMJ diagram above). This was right in the area of the forward elevator. The time was 0810D. The detonation punched a hole into the elevator well, ruptured tanks of aviation gas and fuel oil, as well as knocking the (loadedE) forward elevator loose. It fell about six feet (two meters) and jammed between the flight deck and the upper hanger deckF.

Image from Imperial Japanese Navy Aircraft Carriers 1921-45, Osprey Publishing

    Ozawa ordered the damaged elevator planked over to continue flight operations, and Taiho slowed to 26G knots to reduce the pressure of water on the interior bulkheads of the ship. In about 30 minutes, the job was done. Taiho was down 1.5 meters (4.9 feet) by the bow, but the hole in the deck left by the fallen elevator was covered over using tables and benches from one of the ship's mess halls, and she was able to launch and recover aircraft. There was apparently no list, and the remaining strike aircraft were all on their way before 0900. 

    A handful of aircraft returned to Taiho with engine trouble, and in an unfortunate turn of events, when Raid II flew over the Japanese vanguard force, they came under antiaircraft fire from their own ships. Two planes were shot down, and another eight were forced to return to Ozawa's carriers with damage.

    Despite the apparent silver lining of the quick return of Taiho to flight operations, the patch job on her flight deck concealed the deadly hazard that was building up inside the ship.

    The torpedo hit had opened the hull to the sea, cracked the avgas and fuel oil tanks, and ruptured the deck in the bottom of the elevator well. The volatile aviation fuel and fuel oil mixed with seawater in the bottom of the well and began to vaporize, filling the interior of the ship with fumes. Efforts to ventilate the ship ended in failure, the enclosed flight deck and bow hampered attempts to use the natural draft from the ship's speed. As many hatches and doors as possible were opened to assist in the ventilation, and large fans were activated as well. This only let the vapors into the rest of the ship, furthering the threat, along with shattering Taiho's watertight integrity in the event of further damage. 

    During this time, no one activated the foam dispensers or CO2 dispensers to cover the pool of vaporizing fuel inside the elevator well. While the CO2 would have made the lower hanger unusable, the strike aircraft were already away. An attempt to pump out the elevator during this time also ended in failure.

    At 1350 hours, the few survivors of the Japanese air strike started to return. By then Shokaku was not long for this world as outlined above.  

THE TORPEDOING OF JAPANESE AIRCRAFT CARRIER SHOKAKU, JUNE 19, BY SUBMARINE CAVALLA. Illustration by Jim Laurier. Image from The Philippine Sea by Mark Stille.

The danger of fumes aboard Taiho and the total incapacitation of Shokaku lead to many aircraft landing on the Zuikaku when possible. 

At 1432 hours (see discussion below), something inside Taiho sparked.

    A massive explosion tore through the forward part of the carrier, splitting the armored flight deck and blowing the sides out of the hangar deck just forward of the island. The blast also opened more of the hull below the waterline, killed many of the crew below the deck, and knocked out all power aboard the ship. The ship went dead in the water and began to list to portH. 

    By 1500, the area from the island forward to the bow was a burning wreck, and the ship was rocked by secondary explosions. Damage control was successful at keeping it contained forward of the island, but Ozawa was convinced to move his flag from the devastated warship.

    By 1606I Ozawa had made it aboard the cruiser Haguro via the destroyer Wakatsuki. Taiho was still ablaze, settling by the bow and listing to port. Fuel oil leaking from the crippled carrier had ignited as well, making the area around the stricken ship even more hazardous.

The cruiser Haguro during the Battle of the Sibuyan Sea, October 1944.

Sources vary wildly on how exactly Taiho finally sank: 

Anthony Tully on Combined Fleet:

    At 1628, Taiho sunk on a semi-even keel, though listing to port and down at the bow. About 2/3 of her officers and crew were rescued, but some 660 men (28 officers and 632 petty officers and enlisted men) were lost. This included essentially the entire crews of the engine rooms and boilers, except for a few firemen who made it out from boilers rooms 2 and 6 through holes that had been blasted through the decks.

American Naval Technical Mission to Japan [ANTMJ]:

    Taiho lurched to port, capsized, and sank by the stern around 1500 hours. There were only around 500 survivors.

Mark Stille in The Philippine Sea 1944:

    Taiho exploded at 1532 hours, she sunk on an even keel by the bow, 660 crew lost. 

William Y'Blood in Red Sun Setting:

    Taiho exploded at 1532, Ozawa reached Haguro by 1706, Taiho exploded again at 1828, rolled to port, kept rolling, and went down by the stern. 1,650 men lost out of 2,150, plus 13 aircraft. 

Seiji Higashi in Warships of the Imperial Japanese Navy:
    Taiho exploded at 1432, tilted sharply to port and then sank at 1628 hours.

Col. Hackett's Tabular Record of Movement in Warships of the Imperial Japanese Navy: 

    Taiho exploded at 1532, Ozawa was evacuated to the destroyer Wakatsuki at 1606, Taiho capsized to starboard and sunk with 13 aircraft at 1828 hours, only 660 men out of her crew of 1,751 were lost.

Record of movement by Hisashi Date in Warships of the Imperial Japanese Navy:

    Taiho exploded at 1432, and she sunk at 1628, with the loss of 660 men.

    These discrepancies are ultimately not critical to the intended point, several of them are accurate by minutes and only offset by hours, and many of these sources are fairly old as well, lacking more recent scholarship and access to records. In the end, it was the failings of the officers and crew of the Taiho that resulted in the loss of the ship.

The Aftermath and Conclusions

    Later Japanese carriers had improvements to mitigate the technical failings that lead to the loss of Taiho. 

    Due to the nature of the torpedo hit and damage caused, the IJN filled the spaces around the avgas tanks of its surviving carriers with a solid meter of concrete to mitigate the damage from torpedo hits. In comparison, the United States Navy kept seawater in empty tanks to keep them from filling with vapors as well. This had been considered by the Japanese as well, but apparently Japanese pilots objected to this practice with concerns of fuel contamination.

    From the time that Albacore's torpedo hit for probably several hours after, swift and intelligent action could very well have saved the ship. While Japanese damage control practices have some of the blame, they did recognize the danger, even if they went about combating it poorly. This is almost certainly an issue of crew training, as Shokaku's crew, seasoned veterans from as far back as the attack on Pearl Harbor in 1941 fought hard to save their ship, even though they were unsuccessful in their efforts. Taiho's crew was very green, taking their ship into battle for the first time when she was sunk. 

    VADM Ozawa shares some blame as well, while carrying on with launching his strike was a reasonable course of action considering the dire nature of the situation the Japanese were facing at the time, once the strike was away there wasn't a clear effort from the top to work at verifying the state of the ship and then trying to save it. 

    Activating the foam dispensers to cover the spilled fuel, uncovering the forward elevator for ventilation, and not compromising the ship's integrity could have prevented, delayed, or otherwise mitigated the explosions that doomed the ship. But, that is the point of the Taiho Lesson.

Technology is not a substitute for training.

*A bad design is something like the Vasa, which sank almost as soon as it left port. Or the American Casco class monitors of the American Civil War, which were rendered useless for combat through ever-growing numbers of changes to the design which compromised their buoyancy and trim, to the point that as launched USS Chimo's stern was submerged by as much as four inches even while lightly loaded. 

A: The DANFS page for the USS Albacore (SS-218) says that they found themselves in the midst of the Japanese force around 0800 hours. Silent Victory also says that Albacore spotted the carriers around 0800. 

B: Some sources list the torpedoes as being Mark XXIIIs, while Hackett gives the weapons launched as being four Mark XXIIIs and two Mark XIVs. This difference isn't that important since the Mark XXIII was a modification to the Mark XIV. It removed the 31-knot speed setting, which was seldom used in the war.

C: I have not been able to find the name of the second crew member of the D4Y 'Judy' flown by WO Komatsu, I don't think that the IJN would have sent out a bomber like that on such a critical mission with just the pilot aboard.

D: Kojinsha gives the time of impact as being around 0911, ANTMJ gives the time as being around 0830, and CombinedFleet gives 0810.

E: Hackett says that it was an A6M5 fighter.

F: Some sources say that there was a fire started [Hackett], most others do not mention a fire directly after the torpedo impact. 

G: Hackett lists 21 knots, ANTMJ lists a 1-knot reduction in speed from 26 knots, CombinedFleet lists 26 knots. Hackett lists the Taiho's speed before the torpedo hit as being 27 knots.

H: Tully only mentions the list around the time Ozawa departed, while Hackett says that the list started as soon as the major explosion.

I: Both Tully and Hackett have the same time listed. This seems to be the time Ozawa was actually on board the Haguro, not when he left the Taiho.

Sources:

"IJN Taiho: Tabular Record of Movement" n.d. Combinedfleet.com. http://combinedfleet.com/Taiho.htm.

 

“Albacore II (SS-218).” - Dictionary of American Naval Fighting Ships service history of Albacore.

Evans, David C, and Mark R Peattie. Kaigun : Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887-1941. Annapolis, Md., Naval Institute Press, 2012.

United States Naval Technical Mission to Japan Report S-06-2.

Blair, Clay. 2001. Silent Victory : The U.S. Submarine War against Japan. Annapolis, Md.: Naval Institute Press.

Ahlberg, Lars, Hans Lengerer, and Leszek Erenfeicht. 2004. Taihō. Vol. 1. Gdańsk: Aj-Press.

Stille, Mark, and Tony Bryan. 2005. Imperial Japanese Navy Aircraft Carriers, 1921-45. Oxford: Osprey.

Y'Blood, William T. 1981. Red Sun Setting: The Battle of the Philippine Sea. Annapolis, Md.: Naval Institute Press. 

Tillman, Barrett. 1994. Carrier Battle in the Philippine Sea. St. Paul, Mn.: Phalanx Publishing Co. 

Stille, Mark, and Jim Laurier. 2017. The Philippine Sea 1944: The Last Great Carrier Battle. Oxford: Osprey.

ENGLISH TRANSLATION OF KOJINSHA No.6 ‘WARSHIPS OF THE IMPERIAL JAPANESE NAVY’ - Hosted on CombinedFleet.com

Marine Art gallery of the Imperial Japanese Warships. - Gallery of several high-quality paintings of Japanese warships, by several artists. 

NavSource Photo Archive - USS Bunker Hill (CV-17).