The Sinking of the Musashi

The sinking of the superbattleship Musashi by US carrier aircraft in the battle of the Sibuyan Sea (24 October 1944) gives an idea of Japanese anti-aircraft capability and may be compared to the sinking of Prince of Wales about three years earlier. Musashi was considerably larger than the British battleship, and she absorbed much more damage. The sixteen bombs which hit her did not contribute directly to her sinking, but they did help reduce her anti-aircraft effectiveness and thus indirectly contributed to the success of the torpedo bombers which sank her. The Japanese initially reported that she was struck by twenty-one torpedoes, including two duds, but the US Navy concluded from interrogation of survivors and other Japanese naval personnel that only ten hits and four possible but not probable hits could be identified. Analysis suggested that ten hits equally divided between both sides in the forward three-quarters of the ship would have been enough to sink her. Analysis was complicated because the Japanese did not produce war damage reports comparable to those produced by the US Navy or the Royal Navy, nor were commanding officers required to submit war damage reports. However, both the executive officer and the engineering officer of Musashi kept detailed notebooks, which survived the war.

When she was attacked, Musashi was part of a large Japanese surface action group, Admiral Kurita’s Center Force. It included both superbattleships and three older battleships (Nagato, Haruna and Kongo), plus numerous cruisers and fifteen destroyers. The ship’s CO, Rear Admiral Inoguchi, was a gunnery officer who reportedly placed great faith in the special shrapnel/incendiary shells her main battery could fire. Like Admiral Phillips off Malaya three years earlier, Admiral Kurita asked for fighter cover, which would have been provided by the large naval air force ashore in the Philippines. It was later claimed that ten fighters had been kept aloft over his force, but US attackers saw only four of them, which they quickly shot down. All the losses to the attackers were due to anti-aircraft fire. Musashi had been upgraded considerably since completion, and her numerous 25mm mounts were all controlled by directors comparable to those on board Prince of Wales in 1941. Probably the most significant difference in the two actions was that Musashi was not unfortunate enough to suffer early hits which put her electrical power out of action.

As in the earlier case, prior to the attack the ship was shadowed by a search plane, in this case from the carrier Intrepid. The ship tried unsuccessfully to jam the aircraft’s radio. About two hours later, the first strike (estimated by the Japanese as thirty aircraft, which would be equivalent to Intrepid’s combined torpedo and dive bombing force) arrived. Some aircraft came from the light carrier Cabot. The attack began with eight SB2C dive bombers, which caused minor damage. They were followed by three Avengers, one of which hit the ship amidships, slightly abaft the bridge. The shock of this hit jammed the main battery director, so the ship was unable to fire her 46cm Type 3 shells. Two of the three Avengers were shot down. During this attack the ship fired forty-eight 155mm (low-angle) and sixty 127mm shells. After this attack the ship switched to her after main battery director; changeover of this type was awkward in Japanese ships due to synchro and switchboard design.

About half an hour later the ship’s air-search radar detected a second raid 81km out. A few minutes later the aircraft were sighted, and another eight Helldivers from Intrepid attacked, this time scoring two bomb hits and five near-misses. A bomb fragment which penetrated the muzzle of one gun in No. 1 turret detonated a Type 3 shell which had just been loaded, disabling the turret. Nine Avengers delivered a hammer-and-anvil torpedo attack, eight of them dropping torpedoes. Three hit the port side amidships, flooding one engine room. The director changeover made it possible to fire fifty-four 46cm Type 3 shells. In addition, the ship fired seventeen 155mm and 200 127mm. Bomb damage to an engine room slowed the ship, and she was left down by the bow. The attacking US pilots had never encountered Type 3 shells before, and they were impressed that the Japanese would fire against them at ranges of 25,000 to 30,000 yds, at which the relatively slow train and elevation rates of large-calibre turrets would not be a problem. ‘The fire was surprisingly accurate and somewhat distracting, though no damage was sustained by the planes so attacked.’ US pilots thought the shells were loaded with phosphorus.

About an hour and a half later twenty-nine aircraft from Essex and Lexington attacked, including two strafing Hellcats. Four Helldivers made two hits near starboard amidships and abeam the after 46cm turret, causing casualties among the 25mm crews. Other Helldivers made four bomb hits on the port side. Another hammer and anvil attack, this time by six Avengers, made four more torpedo hits, two on each side. The ship fired another thirty-six 46cm Type 3 shells, plus seventy-nine 155mm and over 500 25mm. The ship was now further down by the bow, reduced to 20kts and thus lagging behind Kurita’s 22kt force.

About two hours later eight Hellcats and twelve Helldivers from Essex attacked two of the other four battleships, Yamato and Nagato. The bomb damage they inflicted had no real effect. At this point the CO of the accompanying cruiser Tone suggested that the ships of the force provide anti-aircraft support for Musashi.

A fifth attack carried out by sixty-nine aircraft from Enterprise and Franklin made four hits with 1000lb AP bombs, three in the bow area, and three torpedo hits. The pilots reported that the ship was dead in the water, heavily down by the bow and smoking. After they left she managed to increase speed to 16kts (soon reduced to 13kts) and she corrected her starboard list.

The sixth and final attack on Kurita’s force was mounted by seventy-five aircraft from Intrepid (thirty-four), Franklin (thirty) and Cabot (one); thirty-seven of them attacked Musashi. They made a total of ten bomb hits, some of which wiped out 25mm guns. It is not clear how many torpedo hits were made, since totals given by different sources vary. A battle narrative gives a total of nineteen torpedo hits (ten to port, nine to starboard), seventeen bomb hits and eighteen near-misses. However, most current Japanese accounts give eleven torpedo hits, ten bomb hits and six near-misses.

A total of 259 US carrier sorties was flown, and eighteen US aircraft were shot down during the attacks, for a loss rate of 6.9 per cent, better than that inflicted by Prince of Wales and Repulse during their final battle. US pilots were unimpressed by the Type 3 shells, and fire by 127mm guns seems to have been limited. The main defence was 25mm guns, for which US pilots had respect. Dive bombing attacks could not sink the ship, but they certainly could destroy the light anti-aircraft guns which were beating off the torpedo bombers. At the least they could help saturate the ship’s anti-aircraft fire control channels. Note that virtually all attacks were combinations of dive bombers and torpedo bombers. It is also obvious that the Japanese had not adopted US-style circular formations with their interlocking fields of anti-aircraft fire. Only at the end did Musashi receive support from other ships (at the end she was attended by the cruiser Tone and the destroyers Shimakaze and Kiyoshimo, neither of them an anti-aircraft destroyer).

This was the first major US air strike against a Japanese capital ship since 1942. In retrospect it seems surprising that attacks were not spread effectively over the rest of Kurita’s force. One answer lies in the way the attacks were carried out, in succession by different Task Groups. No pilots from any one such attack knew what his predecessors had hit, and it was easy to concentrate on one spectacular target. Moreover, pilots in successive waves seem to have thought they were hitting different ships.

Musashi absorbed enormous punishment and in so doing seems also to have absorbed the air striking power available to Task Force 38. Kurita cannot have intended it that way, but because the pilots concentrated on her, they were unable to inflict significant damage on the rest of Kurita’s large surface force. Task force commander Admiral Halsey later commented that the attack showed just how difficult it still was for aircraft to sink a large surface combatant. In effect that was a post-battle justification for his unwillingness to form a battle line (Task Force 34) when he went north to engage the Japanese decoy carrier force. The attack also showed how misleading pilots’ reports could be. They exaggerated the damage they had inflicted on the other battleships (two bombs each on Yamato and Nagato, five near-misses on Haruna). Given their claims, they were too ready to report that they had turned Kurita back. They interpreted ships milling around to support damaged units as ships stopped and ready to retire. Kurita did retire temporarily, calling for strikes by land-based aircraft (which could not materialise) to precede him. On the night after the battle, he turned back towards Leyte Gulf, which had been denuded of capital ship protection on the basis of the exaggerated strike reports.

The most interesting lesson is that battle-damage assessment is the most difficult part of an attack. Issued in March 1945, the Cominch compilation of ‘Battle Experience’ for Leyte Gulf reflects after-action reports. It seems clear that the pilots reported that they had crippled Kurita’s force. TG 38.2, which made more than half the attacks (146 sorties), dropped 23 tons of bombs and twenty-three torpedoes. Its pilots reported that they had hit Yamato with three torpedoes and hit a sister ship (possibly the same ship) with one torpedo and two bombs; that they had hit the battleship Nagato with a torpedo and a bomb; that one Kongo class battleship had been hit by two torpedoes and six bombs; a Mogami class cruiser had possibly been sunk by a torpedo; the cruiser Nachi had been hit by one torpedo. Task Group 38.3 reported one bat-tleship badly hit, two others damaged, and four heavy and two light cruisers damaged. Task Group 38.4 reported one battleship (Musashi?) hit by a torpedo, on fire, down at the bow and probably sunk, one Yamato class battleship hit by one to three torpedoes and two bombs; a Kongo class battleship hit once by a bomb, one light cruiser sunk, one destroyer sunk, one destroyer probably sunk and four destroyers damaged. Although some of this information was not immediately relayed to Admiral Halsey, the impression that great damage had been done was unmistakeable. Halsey was convinced; in his after-action report he wrote that the enemy had turned back to attack off Samar out of blind obedience to an Imperial command to do or die.

It was soon obvious that the pilots had exaggerated about as badly as the Japanese had when they reported sinking the US fleet several times over after attacking the Task Force off Formosa just before Leyte Gulf. In March 1945 Cominch credited the pilots with having damaged Musashi and sunk the heavy cruiser Haguro. In fact the cruiser was quite intact, having steamed south, but Musashi had been sunk. Unlike the Japanese, who orbited the crippled British capital ships to make sure they were sunk, the US carriers did not maintain anyone over the battle scene to be sure of what happened. That was partly due to range (the battle was at extreme strike range for the Task Force) and probably also because the need for such assessment had not been driven home.

The Cominch combat analysis emphasised the problems pilots faced in evaluating their results. In a secret letter, CinCPAC Admiral Nimitz pointed out the problem, and Cominch clearly felt it had to be repeated. Nimitz quoted a report after an air strike early in the war: one 15,000-ton transport (AP) on fire and beached; one transport (AP) sunk and burning; one transport or cargo ship beached and probably sunk; one transport or cargo ship sunk, bottomed in shallow water, and listing; one Mogami class cruiser blown up and sunk; one Kinugasa class cruiser afire and headed for the beach, believed sunk; one light cruiser headed for the beach, believed sunk; one seaplane tender (Kamoi class) damaged and stopped; one destroyer listing, afire, and sinking fast; two other destroyers probably sun; one gunboat set afire and severely damaged; one minesweeper stopped and burning fiercely, probably sunk. Confirmed sinkings were actually three cargo ships of 4000 to 6000 tons. No warships were sunk.

Nimitz did not want to ruin his pilots’ enthusiasm, but he did want them to know that there could be a gap between good-faith reports and reality. The worst problem was that it was generally unwise to remain in an area to assess results, as long as any ships and their AA crews survived to keep firing. With so many aircraft involved, reports would necessarily be duplicated, and they might be difficult to disentangle. Pilots tended to be over-optimistic about the effects of their attacks: there could be tremendous explosions topside, yet a ship might still get underway and get home. Pilots could also be over-optimistic about near-misses: if near enough, they could certainly do tremendous damage, but then again they might not. Similarly, there was over-optimism as to fire and smoke: a small and possibly harmless fire could produce a great deal of smoke. Even ships afire from stem to stern could survive. There was over-valuation of ships ‘beached and sunk’. A damaged ship might well beach herself lightly until the attack was over – but she would survive. Finally, Nimitz cited the ‘lack of familiarity with ships on the part of many pilots, which handicaps them in distinguishing types and tonnages and in estimating the seriousness of the damage or the probability of a ship sinking’. This last point applies to nearly all the examples of air-sea combat already quoted.

The attack on the battleship Yamato in April 1945 contrasts with that against Musashi. The US Navy seems to have realised that the ship’s sheer capacity to absorb aerial punishment ensured that strike aircraft would keep coming back to attack her rather than distribute their fire among the ships in the Japanese surface strike force. This time the strikes were very differently organised. Each of the groups launched by a Carrier Task Group had a coordinator. The effect of coordination shows in that considerable numbers of torpedoes were devoted to the other ships in the force. It probably helped that Yamato was the only large ship in her task force, the others being the light cruiser Yahagi and eight destroyers. Concentrating on the one large ship did not have the unfortunate effects of the concentration on Musashi which left the other ships of the surface strike group effectively undamaged to fight the battle off Samar the next day.

Task Force 58 was alerted on the night of 6–7 April by two US submarines (Threadfin and Hackleback) patrolling the Bungo Suido Channel (reportedly the Japanese intercepted the uncoded sighting reports). At dawn the Task Groups launched a total of forty aircraft, all fighters, in groups of four, to search to a depth of 325nm. At 08.22 an Essex search aircraft reported one battleship, probably Yamato class, two cruisers, and eight destroyers making 12kts. The fighter could not contact the carrier directly via her VHF line-of-sight radio, but linking aircraft had been launched. She radioed via them (100 and 200nm away). The next step was to shadow the enemy group, so that a strike group could be vectored to them. At 09.56 a tracking and covering force of sixteen fighters was launched, followed at 10.00 by strikes from Task Groups 58.1 and 58.3 and 45 minutes later by a strike from Task Group 58.4.

All three Task Groups were to have launched together, but the Hancock strike (12 torpedo bombers, 15 dive bombers, and 24 fighters) was 15 minutes late on take-off and failed to join up (and hence to find the targets). This was an immense force, totalling 386 aircraft: 113 from TG 58.1 (52 fighters, 21 dive bombers, 40 torpedo bombers), 167 from TG 58.3 (80 fighters, 29 dive bombers, and 58 torpedo bombers), and 106 from TG 58.4 (48 fighters, 25 dive bombers, 33 torpedo bombers). All the torpedo bombers carried torpedoes. The dive bombers (Helldivers) carried 1000lb SAP and underwing 250lb GP bombs. Each fighter had a 500lb GP bomb and a long-range drop tank. This huge strike left enough fighters with Task Force 58 to deal with enemy attacks (a Kamikaze crashed into the carrier Hancock while the strike was away). The launch position was about 250nm from the estimated position of the Japanese force (i.e., aircraft would have to fly about 240nm). All of the searching was needed: the enemy force unexpectedly turned north, to be found again by a land-based search aircraft from Okinawa. It shadowed the enemy force for the rest of the day, but shadowing reports failed to get through to the Task Force Commander. It turned out that it did not matter very much because the strike leaders were soon in touch with the shadower. Final homing was by APS-4 radar on Helldivers, which picked up the enemy force at 32nm from 6000ft.

When first sighted, the Japanese force was 70nm from the first sighting position. A combination of poor weather and the sheer size of the attacking force made the attack difficult to coordinate. Anti-aircraft fire was heavy but ineffective, and the three Task Groups attacked roughly in sequence, TG 58.1 and 58.3 first and then TG 58.4.

The attack developed in three phases, of which the first consisted of two almost simultaneous attacks. The first two strike groups hit not only Yamato but also the cruiser and three destroyers. The attacks began with strafing to suppress her light anti-aircraft battery. This time the torpedo bombers concentrated on one side of the ship. The first two bomb hits around around No 2 turret. wrecked a 12.7cm anti-aircraft mount and many light anti-aircraft guns. Another two, inflicted a few minutes later, wrecked the after secondary battery director and exploded above the protective deck, starting a fire which was never extinguished. The after 15.5cm mount was gutted. At least the first two hits seem to have been by 500lb GP bombs rather than AP bombs. A second wave of attacks began 40 to 45 minutes later, inflicting three or four torpedo hits on the port side and one on the starboard side. There were no bomb hits. About thirty minutes later a third and last attack began. The ship took two more torpedoes to port and one more to starboard (some Japanese officers thought there were additional hits, but the post-war US analysis discounted that). Altogether Yamato seems to have taken at least nine torpedo hits (plus three possible, but improbable), of which seven were on her port side and two on her starboard side. The ship also took at least four hits from dive bombers.

Yamato capsized to port 20 to 30 minutes after the last three torpedo hits, her magazines exploding as she rolled over. Both the Assistant Gunnery Officer and the Chief of Staff told US officers after the war that they believed that the fire aft ignited the magazines of the after 15.5cm mount, passing to them as the ship rolled over. A study of main battery shell fuses militated against the alternative explanation, given by the ship’s Executive Officer, that as the ship rolled over her HE and incendiary AA shells fell out of their racks in all three 46cm magazines, hit their noses on the deck, and exploded.

US losses amounted to ten aircraft (four dive bombers, three torpedo bombers, and three fighters) and twelve aircrew (four pilots and eight crew).

Assessed results were Yamato and a light cruiser (Yahagi) sunk, as well as four destroyers, plus one badly damaged (Akizuki class) and one left burning. In fact the light cruiser was sunk (she took, among other damage, six torpedoes) and the initial wave sank the destroyer Isokaze and damaged two others so badly that they had to leave the area (one of them, Hamakaze, later sank). Later waves sank the destroyer Asashimo and damaged Kasumi so badly that she sank. Three destroyers rescued survivors and returned to Japan. Thus the assessment in the after-action report was far more accurate than it had been in the October 1944 action, perhaps as a result of Nimitz’ comments at the time. A search and a fighter sweep (thirty-two fighters armed with bombs) the next day failed to find the surviving Japanese ships.

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