Decisive battle at Caroline Islands (WW II)

[mutiafarida3]

What if Imperial Japanese Navy decide to make a stand in Marshal Island when Operation Hailstone (the raid of Trukk Harbour in February 1944) commenced?

Will the IJN able to defeat the raiding forces? Can this battle intensified into a decisive battle like OTL Battle of Philippine Seas?

 

[Logan2879]

Not really because the majority of the japanese fleet were in japanese ports by February 17 and also Operation Hailstone was top secret which means the Japanese did't know where the American fleet will strike. Now if the Japanese didn't send its fleet to Japan then maybe a battle could have gone threw.

 

[mutiafarida3]

Not really because the majority of the japanese fleet were in japanese ports by February 17 and also Operation Hailstone was top secret which means the Japanese did't know where the American fleet will strike. Now if the Japanese didn't send its fleet to Japan then maybe a battle could have gone threw.

Forgive if I'm wrong...cause I'm not a historian.

The IJN already evacuate the Trukk harbour of any major capital ships and a number of aircrafts before the Operation started because they already suspect a major raid were coming. When USN hit Trukk, most ships still in the area were merchant ships and light cruisser & destroyer.

 

[Logan2879]

Then you answer your question. But also if the japanese admiral wanted battle then things could have been diferrent.

 

[galveston bay]

The Japanese were pretty weak in naval air power at that particular time, having suffered decisive and shattering losses in South Pacific campaign and had barely started rebuilding the airgroups they lost. Those airgroups were still under trained when they were slaughtered in June 1944 in the Marianas Turkey Shoot. So what you need is a POD where the Japanese don't commit their carrier and land based air to the attrition war in the Solomons and New Guinea

 

[Athelstane]

The Japanese were pretty weak in naval air power at that particular time, having suffered decisive and shattering losses in South Pacific campaign and had barely started rebuilding the airgroups they lost. Those airgroups were still under trained when they were slaughtered in June 1944 in the Marianas Turkey Shoot. So what you need is a POD where the Japanese don't commit their carrier and land based air to the attrition war in the Solomons and New Guinea

This.

They were still frantically trying to rebuild their air groups after the mauling they took in the Solomons. The Marshalls and Carolines were written off as expendable as a result.

And as we know now, even by the time of the Marianas, they still weren't close to ready - the IJN just didn't appreciate how wide the gap in carrier air power had become.

But I get that this only answers *why* the IJN under Koga chose not to contest American moves into these island groups. Why if Koga had chosen to fight? He'd have lost, big time. If Mitscher's fast carrier force was not *quite* as powerful as it would have been in June, Koga was in even worse shape. Not only did he not have the Taiho yet (it commissioned only in March), Koga did not even have air groups to fill out the carriers he *did* have. He also could not make use of the land-based "shuttle bombing" that was such a crucial (though doomed to fail) part of the Japanese strategy in the Marianas.

 

[mutiafarida3]

Are Japanese pilots quality already that bad at this point?

If Japanese choose to fight, are the result will be like "Mariana Turkey Shoot"?

 

[Carl Schwamberger]

Are Japanese pilots quality already that bad at this point?

If Japanese choose to fight, are the result will be like "Mariana Turkey Shoot"?

In the case of the carrier trained pilots yes. The core problem was the training program had so few pilots graduating each month it was unable to replace losses on a 1-1 basis. The USN was training four or five pilots for each lost. Simply bringing the survivng carriers up to strength with rookie pilots meant keeping the carrier fleet out of the fight for nearly a year.

A second problem was the shortage of fuel and training cadre. The Japanese rookies were not getting even half the school flight hours their predecessors, or the USN pilots, received. That problem extended somewhat when they joined the operational air units & started follow on training. The loss of experienced pilots meant the ratio of students to experienced instructors was very high. Their training was not nearly as through as the USN or AAF piiots were receiving in 1943.

Similar problems plagued the Navy and Army land based air units. By the end of 1942 the IJN land based air groups were nearly non existant. The Army had considerable forces in China to drawn on as a reserve, but that was finite, and hampered ops there, plus the IJA air groups had little training for maritime operations.

 

[Zheng He]

In the case of the carrier trained pilots yes. The core problem was the training program had so few pilots graduating each month it was unable to replace losses on a 1-1 basis. The USN was training four or five pilots for each lost. Simply bringing the survivng carriers up to strength with rookie pilots meant keeping the carrier fleet out of the fight for nearly a year.

A second problem was the shortage of fuel and training cadre. The Japanese rookies were not getting even half the school flight hours their predecessors, or the USN pilots, received. That problem extended somewhat when they joined the operational air units & started follow on training. The loss of experienced pilots meant the ratio of students to experienced instructors was very high. Their training was not nearly as through as the USN or AAF piiots were receiving in 1943.

Similar problems plagued the Navy and Army land based air units. By the end of 1942 the IJN land based air groups were nearly non existant. The Army had considerable forces in China to drawn on as a reserve, but that was finite, and hampered ops there, plus the IJA air groups had little training for maritime operations.

Late in 1942 they started stripping the CAGs for operations from land bases.

 

[BobTheBarbarian]

This isn't the Caroline Islands, but if the IJN had decided to follow through with its mission against Biak instead of turning to its destruction in the Philippine Sea they could have done quite a bit of damage there. They would have engaged only a smaller portion of the greater United States fleet with an overwhelmingly stronger task force of its own. Had they chosen to continue that route it would have thrown the naval support for the Saipan operation badly off balance.

 

[Athelstane]

This isn't the Caroline Islands, but if the IJN had decided to follow through with its mission against Biak instead of turning to its destruction in the Philippine Sea they could have done quite a bit of damage there. They would have engaged only a smaller portion of the greater United States fleet with an overwhelmingly stronger task force of its own. Had they chosen to continue that route it would have thrown the naval support for the Saipan operation badly off balance.

They *could* have, but the Marianas were seen as *must defend* positions. Because their loss would not only lay so much of the Japanese Inner Empire open to attack, but also leave the home islands open to American strategic bombing.

In any event, you're contending here with the Japanese "decisive battle" complex. They were waiting for the opportunity to wage such a battle the moment their air groups were anything like ready to deploy. As it was, Toyoda was already looking for opportunities to lure the U.S. fast carrier forces in for such a battle (A-GO), preferably in the region between the Palaus, Yap and Woleai. The appearance of Spruance's armada off Saipan fit the bill too, however.

In short, you need a major overhaul in Japanese doctrine in order to keep the Japanese in persisting with the Biak operation when Spruance and Turner are busy overrunning Sapain - especially since it means delaying any IJN attack on the Marianas until after the U.S. has not only neutralized all Japanese airbases in the Marianas, but have started establishing their own - which deprives any Japanese strategy for securing the islands of an absolutely critical element.

 

[BobTheBarbarian]

It also lead the inexperienced Japanese carrier force to sail right into the teeth of the USN air arm and get slaughtered. From a "decisive battle" standpoint it was pointless, unless the objective is to give a decisive battle to the Americans. At least by attacking Biak they could hopefully lure the opposing fleet into battle on more favorable terms and perhaps exact a more meaningful toll.

 

[Zheng He]

Another reason for giving battle at the Marianas was that the combination of carrier based and land based aircraft gave the Japanese something like parity on paper and the carrier planes could recover at the land bases if necessary. On paper Ozawa's strategy was sound, it's just that by this point in the war the qualitative advantages of American personnel and equipment were overwhelming (to include submarine torpedoes that actually functioned as advertised).

 

[CalBear]

The Easiest answer is that it wouldn't have mattered. The Japanese would have suffered slightly less losses in aircraft than at Philippine Sea, but would likely lose more carriers (the plan for Saipan was designed to protect the what was left of the Kido Butai by shuttling through Saipan's air fields) Mitscher was held back at Philippine Sea by Spruance in order to defend the landing force. Spruance was concerned that the Japanese might wrong-foot him by drawing his carriers off and then sneaking in a heavy surface force of cruisers and maybe a fast BB to attack the transports, he was constantly being reminded not to "pull a Fletcher". At Truk, that wouldn't have been an issue. The IJN comes out to fight and the Americans will provably offer some fuel to get them there.

 

[Athelstane]

It also lead the inexperienced Japanese carrier force to sail right into the teeth of the USN air arm and get slaughtered. From a "decisive battle" standpoint it was pointless, unless the objective is to give a decisive battle to the Americans. At least by attacking Biak they could hopefully lure the opposing fleet into battle on more favorable terms and perhaps exact a more meaningful toll.

The problem is, the Marianas are a lot more important to Japan than Biak is. Pretty awful tradeoff for them.

And even if Ozawa were to lure Spruance down there, he can't shuttle as many land-based aircraft into that area as he can the Marianas.

Taking a page from Calbear...Hell, if I were Spruance, I would offer Ozawa the fuel to get to Biak. As Sherman said of Hood: "D -- n him! if he will go to the Ohio River I'll give him rations!"

 

[BobTheBarbarian]

The problem is, the Marianas are a lot more important to Japan than Biak is. Pretty awful tradeoff for them.

And even if Ozawa were to lure Spruance down there, he can't shuttle as many land-based aircraft into that area as he can the Marianas.

Taking a page from Calbear...Hell, if I were Spruance, I would offer Ozawa the fuel to get to Biak. As Sherman said of Hood: "D -- n him! if he will go to the Ohio River I'll give him rations!"

Sortieing against the Marianas did a whole lot of nothing though, and the islands themselves were a lost cause. Outnumbered more than 3 to 1 with no hope of reinforcement and a major part of the defending garrison landing as weaponless survivors from transports sunk from under them a few days before there were no realistic chances of doing anything to improve the situation there. All Ozawa did was let the Americans kill two birds with one stone by both piercing the inner ring of Japan's defenses and letting the Kido Butai impale itself on Spruance's veteran fliers. Ultimately it wouldn't have made much difference, but it would have allowed the Japanese to exact a more meaningful toll on the Americans instead of trading their remaining carrier power for 120 US aircraft.

At least instead they could have kept their BBs and CAs committed to Operation KON, while the aircraft carriers went north. Even under those circumstances they stood a good chance of overpowering the US forces around Biak and even landing reinforcements rather than sailing around uselessly as escorts.

 

[Athelstane]

Sortieing against the Marianas did a whole lot of nothing though, and the islands themselves were a lost cause. Outnumbered more than 3 to 1 with no hope of reinforcement and a major part of the defending garrison landing as weaponless survivors from transports sunk from under them a few days before there were no realistic chances of doing anything to improve the situation there. All Ozawa did was let the Americans kill two birds with one stone by both piercing the inner ring of Japan's defenses and letting the Kido Butai impale itself on Spruance's veteran fliers. Ultimately it wouldn't have made much difference, but it would have allowed the Japanese to exact a more meaningful toll on the Americans instead of trading their remaining carrier power for 120 US aircraft.

At least instead they could have kept their BBs and CAs committed to Operation KON, while the aircraft carriers went north. Even under those circumstances they stood a good chance of overpowering the US forces around Biak and even landing reinforcements rather than sailing around uselessly as escorts.

1. Again, the question is the great disparity of the Strategic value of each target. The Marianas were the key linchpin of Japanese inner empire, well within B-29 bombing range of the home islands, with all that entailed. Whereas Biak itself was valuable merely as a defense of the southern Philippines.

2. The Marianas also had great political value, as Saipan and Tinian were considered integral parts of the Japanese homeland, with Japanese civilians living there. The fall of Saipan brought down Tojo's government for this reason, in no small part.

3. The real problem, as you say, is that it makes little difference either way: if the U.S. now has fast carrier force that the IJN simply cannot defeat, it will roam at will through the Japanese empire, bringing along Turner's amphibious forces to pick off one possession after another - and Japan is doomed. But the IJN (and for that matter, the USN) did not realize just how great the disparity of power was between Mitcher's fast carrier forces and its own Combined Fleet. If they had, well... But they though that they really had a shot to damage it badly enough to force its withdrawal, which would leave the U.S. forces fighting on Saipan in a terrible situation.

The Japanese just had no good options at this point. But the longer they held off taking on Mitscher's fast carrier forces, the worse the encounter would end up being, given how rapidly it was being augmented with more ships, planes, personnel, and experience.

 

[Sir Chaos]

Mitscher was held back at Philippine Sea by Spruance in order to defend the landing force. Spruance was concerned that the Japanese might wrong-foot him by drawing his carriers off and then sneaking in a heavy surface force of cruisers and maybe a fast BB to attack the transports.

Sounds suspiciously like what happened at Leyte Gulf... was what Halsey pulled there a reaction to Spruance´s perceived "failure" to destroy the IJN once and for all?

 

[CalBear]

Sounds suspiciously like what happened at Leyte Gulf... was what Halsey pulled there a reaction to Spruance´s perceived "failure" to destroy the IJN once and for all?

Not as such. It reflected more the difference between the two men and their style of command. Halsey was much more of a gambler, far more aggressive than Spruance, who always kept the ultimate mission in mind. Spruance had to keep Mitcher on a tight leash (even then he would jump the gun, as he did with the Yamato, launching well before Spruance had decided to use airpower to kill her rather than one lest big gun showdown) while Mitcher had to run to keep up with Halsey.

Both men had great success (it is an open question if Spruance would have sent Washington and South Dakota, with only four destroyers, into the Slot in November of 1942 which turned out to be one of the best tactical decisions of the War), but they were very different.

 

[BobTheBarbarian]

1. Again, the question is the great disparity of the Strategic value of each target. The Marianas were the key linchpin of Japanese inner empire, well within B-29 bombing range of the home islands, with all that entailed. Whereas Biak itself was valuable merely as a defense of the southern Philippines.

2. The Marianas also had great political value, as Saipan and Tinian were considered integral parts of the Japanese homeland, with Japanese civilians living there. The fall of Saipan brought down Tojo's government for this reason, in no small part.

3. The real problem, as you say, is that it makes little difference either way: if the U.S. now has fast carrier force that the IJN simply cannot defeat, it will roam at will through the Japanese empire, bringing along Turner's amphibious forces to pick off one possession after another - and Japan is doomed. But the IJN (and for that matter, the USN) did not realize just how great the disparity of power was between Mitcher's fast carrier forces and its own Combined Fleet. If they had, well... But they though that they really had a shot to damage it badly enough to force its withdrawal, which would leave the U.S. forces fighting on Saipan in a terrible situation.

The Japanese just had no good options at this point. But the longer they held off taking on Mitscher's fast carrier forces, the worse the encounter would end up being, given how rapidly it was being augmented with more ships, planes, personnel, and experience.

Can't argue with anything you posted as all of the above is true, though I will reiterate that Ozawa's sortie against Sapian achieved jack all and didn't disrupt the invasion schedule in the least bit. On the other hand, I continue to maintain that even a reduced operation KON retaining Yamato, Musashi, and Fuso with their escorts could have produced a Japanese victory in the South Pacific and would have given the Allies a major headache, even allowing for the Turkey Shoot in the Marianas. It would have been the last chance for IJN surface forces to do serious damage to the USN prior to Leyte Gulf, a chance that was itself largely thrown away by Kurita's timidity.