Battle of the North Pacific 1943 (Alt. Scenario).

[Tangles2]

Greetings All.
Just want to run the idea of an alternate naval battle in the North Pacific in mid-late 1943 which I think offers a dynamic and interesting battle scenario. It is built around the US recapture of Attu, and what struck me at first look was the potential imbalance of the force levels I know about. When the US recaptured the island the major units I can see covering the assault were three of the old Pearl Harbour BBs and a single CVE. Were there additional covering forces and if so what were they? IRL the IJN mustered a major force (The fleet included the carriers Zuikaku, Shōkaku, Jun'yō, Hiyō, the battleships Musashi, Kongō, Haruna, and the cruisers Mogami, Kumano, Suzuya, Tone, Chikuma, Agano, Ōyodo, and eleven destroyers.) The Americans, however, recaptured Attu before the fleet could depart. This represented a major force at this stage of the war and the 'what if' I propose is their actual involvement in a battle. Ideas like major bad weather delaying the landing, early detection, major IJN units training in the Kuriles/north of Hokkaido, etc, caused the confrontation to take place. That there are many possible ways to play this out is appealing and the isolation from PH and the central Pacific to a degree acts to level the playing field to wargame the scenario out. I'd be interested in other's possible ideas on such a scenario, and what forces if any were in a covering force, or could have been despatched by the USN. Options are many for a good old-fashioned stoush and I'd be interested to hear any takes on this. Hope you all will throw up some feedback and I look forward to seeing what gets run up the flagpole. Tangles.

 

[CV12Hornet]

Well, for one, there were four American battleships: Idaho, New Mexico, Mississippi, and Pennsylvania swapped for Nevada right around the time the Japanese assembled their fleet. Three heavy and three light cruisers rounded out the force. And Junyo did not participate; the fourth Japanese carrier was Zuiho.

For another, given the weather in the Aleutians odds are the Japanese carrier planes are going to be grounded; if they aren’t, they have to deal with 128 land-based fighters, heavy on P-38s. Not to mention 54 bombers and 30 PBYs.

No, if there’s a battle it’s probably going to be a surface engagement, and that’s not something likely to go in Japan’s favor. They have to leave behind some ships to cover their carriers, and even with Musashi the Japanese don’t really have enough battleship firepower to fight past four Standards.

 

[Tangles2]

Well, for one, there were four American battleships: Idaho, New Mexico, Mississippi, and Pennsylvania swapped for Nevada right around the time the Japanese assembled their fleet. Three heavy and three light cruisers rounded out the force. And Junyo did not participate; the fourth Japanese carrier was Zuiho.

For another, given the weather in the Aleutians odds are the Japanese carrier planes are going to be grounded; if they aren’t, they have to deal with 128 land-based fighters, heavy on P-38s. Not to mention 54 bombers and 30 PBYs.

No, if there’s a battle it’s probably going to be a surface engagement, and that’s not something likely to go in Japan’s favor. They have to leave behind some ships to cover their carriers, and even with Musashi the Japanese don’t really have enough battleship firepower to fight past four Standards.

Tks for the above CV I really appreciate the input. According to the order of battle I have, TF51.1 only consisted of three BBs Idaho, Pennsylvania, and Nevada and the CVE was Nassau, with 2xCA, and 5xCL plus screen forming the surface forces and three SS forming the submarine group supporting the attack. So obviously this differs from the force structure you outlined above. Were there other forces acting as distant cover? I can't find New Mexico or Mississippi in the operational plans for the invasion. Can you give us a link to how you included them? I'd already pretty much formed the same opinion as you that this scenario offered a perfect setup for a BB vs BB battle so it's an interesting one to consider, and definitely, the weather would be a major factor. The records I have indicate that Zuiho arrived at Sasebo on 9 May and underwent a brief refit (to Mid-June?) before joining Zuikaku and Shokaku as part of the 1st Carrier Div. As the invasion of Attu was from 11-30 May where did you find her inclusion? That Junyo was listed with the other three carriers for operation I-Go in April and then there's a gap, where I can't find how she was deployed. I'd be interested in the source that indicates how she was replaced. Any other insight or ideas you think might be of further interest would be welcome. Also, do you have any idea if other US subs may have been deployed to cover the Kurile/Aleutian waters in that time frame? T

 

[CV12Hornet]

I’ll post my sources later today.

 

[Tangles2]

I’ll post my sources later today.

Tks, such help is always both interesting and appreciated. T

 

[CV12Hornet]

Alright, my source for the Japanese fleet is combinedfleet.com's excellent Tabular Records of Movement, specifically Musashi's:

17 May 1943:
Admiral Koga sorties from Truk for Yokosuka in response to the Attu invasion with BatDiv 1's MUSASHI, BatDiv 3's KONGO and HARUNA, CarDiv 2's HIYO, CruDiv 8's TONE, CHIKUMA and DesDiv 24's UMIKAZE and DesDiv 27's ARIAKE and SHIGURE, DesDiv 61's HATSUZUKI and SUZUTSUKI. MUSASHI also carries Admiral Yamamoto's ashes to Tokyo for a state funeral.
20 May 1943:
Alerted by "Ultra", USS SAWFISH (SS-276) picks up MUSASHI task force on radar at 32-45N, 136-35E, but the submarine is unable to attack.
22 May 1943:
USS TRIGGER (SS-237) sights the task force off Tokyo Bay, but the submarine is unable to attack. The task force arrives safely. MUSASHI drops anchor at the Kisarazu Bight. That evening, a Buddhist ceremony is held aboard. Yamamoto's ashes are sent ashore the next day aboard destroyer YUGUMO.
Carriers ZUIKAKU, SHOKAKU and ZUIHO and light cruisers AGANO and OYODO join the task force at Yokosuka, Tokyo Bay. CruDiv 7's KUMANO, MOGAMI and SUZUYA also arrives from Tokuyama. Before this powerful force can depart for a counterattack against the Aleutians, Attu falls to U.S. forces.

Imperial Battleships

Zuiho's TROM confirms her arriving in Yokosuka on May 21, a day before Musashi arrives:

21 May 1943:
Arrive at Yokosuka.

Imperial Flattops

While Junyo lists her south operating in the Solomons area:

14 May 1943:
Cardiv 2's aircraft attack Milne Bay, New Guinea. They hit and sink Dutch freighter VAN HEEMSKERK carrying troops and equipment. Four crewmen are KIA.

3 May 1943:
Assignment changed to Forward Force Air Force, under tactical command of forward force. Vessel remains at Truk through end of month.

Imperial flattops

My source on the American fleet comes from here:

Task Force 16

Task Force 51

 

[Belisarius II]

This kind of action is unlikely but not impossible. The Japanese carrier groups were tied up fighting from bases in the South Pacific, while new groups were in training. I have the impression that the Japanese carriers didn't get their air groups back till October. In fact, they were conducting operational training in the Central Pacific just before Operation Galvanic, the invasion of Tarawa. The Japanese declined to oppose Galvanic, and Attu was in a much less sensitive area than the Gilbert Islands. The IJN was saving its fleet strength for "The Decisive Battle", rather than using battleships in the hopes of gaining tactical victories.

If the Combined Fleet sailed north to oppose "Landcrab" the invasion of Attu, HYPO & OP-20-G would almost surely intercept their radio traffic deigning the IJN operational surprise. Nimitz would have at least several days to assemble more ships to cover Landcrab before the Japanese fleet could even assemble. Truk is even further from Attu than Pearl Harbor is, giving Nimitz a chance to set up another ambush of the IJN like he did at Midway.

I see reference to both USS North Carolina & Washington being in Pearl Harbor during April 1943 to upgrade radar, and for combat training. Both might still be close enough to PH during early May to be sent north in support of Landcrab. USS Essex was on her way to PH in May 43 and might be able to join the battle. I'd have to do a lot more research to find out what USN ships might be available for your battle scenario but shifting the war north like this would be a major shift in strategy for both sides.

 

[CV12Hornet]

South Dakota and Alabama were in Scapa Flow keeping an eye on Tirpitz. Indiana and Massachusetts were in the Solomons area with Enterprise and Saratoga; they probably can't be recalled in time. None of the Independences nor later Essexes are available. Colorado and Maryland are down south as well, California and West Virginia are still being rebuilt, and that leaves recalling Pennsylvania and maybe getting Tennessee into the theater early - she was on the West Coast in May. So practically speaking it's Washington, North Carolina, Pennsylvania, and maybe Essex and Tennessee for additional heavy units.

Cruisers are even more thin on the ground. Indianapolis is already in the combat area, though not directly attached, and can be shuffled into the lineup pretty easily. Vincennes is in Pearl Harbor and Portland on the West Coast, the latter already scheduled to go up north. They can be expedited.

The Japanese can also pull together more ships if they want to. Yamato was historically drydocked this month for a refit, but could probably be pulled in. Nagato, Mutsu, Fuso, Yamashiro, and Ise are all theoretically available, though in practice only Nagato and Mutsu are worth hauling along. Myoko and Haguro were apparently also assigned to the attack on Attu as well, and given Takao, Atago, and Chokai spent this month swinging at anchor in Truk you could pull the former two in as well; Chokai was busy with a reinforcement run to Rabaul until the end of April and probably has to be left behind.

I'm not looking into escort carriers or destroyers.

So we could be looking at a very large surface action - 6-9 Japanese battleships and 9 heavy cruisers against 6-8 American battleships, 5 heavy cruisers, and 4 light cruisers.

 

[Tangles2]

Alright, my source for the Japanese fleet is combinedfleet.com's excellent Tabular Records of Movement, specifically Musashi's:

Imperial Battleships

Zuiho's TROM confirms her arriving in Yokosuka on May 21, a day before Musashi arrives:

Imperial Flattops

While Junyo lists her south operating in the Solomons area:

Imperial flattops

My source on the American fleet comes from here:

Task Force 16

Task Force 51

Tks for that and the attached links, its much appreciated. J

 

[Tangles2]

This kind of action is unlikely but not impossible. The Japanese carrier groups were tied up fighting from bases in the South Pacific, while new groups were in training. I have the impression that the Japanese carriers didn't get their air groups back till October. In fact, they were conducting operational training in the Central Pacific just before Operation Galvanic, the invasion of Tarawa. The Japanese declined to oppose Galvanic, and Attu was in a much less sensitive area than the Gilbert Islands. The IJN was saving its fleet strength for "The Decisive Battle", rather than using battleships in the hopes of gaining tactical victories.

If the Combined Fleet sailed north to oppose "Landcrab" the invasion of Attu, HYPO & OP-20-G would almost surely intercept their radio traffic deigning the IJN operational surprise. Nimitz would have at least several days to assemble more ships to cover Landcrab before the Japanese fleet could even assemble. Truk is even further from Attu than Pearl Harbor is, giving Nimitz a chance to set up another ambush of the IJN like he did at Midway.

I see reference to both USS North Carolina & Washington being in Pearl Harbor during April 1943 to upgrade radar, and for combat training. Both might still be close enough to PH during early May to be sent north in support of Landcrab. USS Essex was on her way to PH in May 43 and might be able to join the battle. I'd have to do a lot more research to find out what USN ships might be available for your battle scenario but shifting the war north like this would be a major shift in strategy for both sides.

Not necessarily implausible but interesting, that's what would make it a good one to massage and see what occurs. T

 

[Tangles2]

South Dakota and Alabama were in Scapa Flow keeping an eye on Tirpitz. Indiana and Massachusetts were in the Solomons area with Enterprise and Saratoga; they probably can't be recalled in time. None of the Independences nor later Essexes are available. Colorado and Maryland are down south as well, California and West Virginia are still being rebuilt, and that leaves recalling Pennsylvania and maybe getting Tennessee into the theater early - she was on the West Coast in May. So practically speaking it's Washington, North Carolina, Pennsylvania, and maybe Essex and Tennessee for additional heavy units.

Cruisers are even more thin on the ground. Indianapolis is already in the combat area, though not directly attached, and can be shuffled into the lineup pretty easily. Vincennes is in Pearl Harbor and Portland on the West Coast, the latter already scheduled to go up north. They can be expedited.

The Japanese can also pull together more ships if they want to. Yamato was historically drydocked this month for a refit, but could probably be pulled in. Nagato, Mutsu, Fuso, Yamashiro, and Ise are all theoretically available, though in practice only Nagato and Mutsu are worth hauling along. Myoko and Haguro were apparently also assigned to the attack on Attu as well, and given Takao, Atago, and Chokai spent this month swinging at anchor in Truk you could pull the former two in as well; Chokai was busy with a reinforcement run to Rabaul until the end of April and probably has to be left behind.

I'm not looking into escort carriers or destroyers.

So we could be looking at a very large surface action - 6-9 Japanese battleships and 9 heavy cruisers against 6-8 American battleships, 5 heavy cruisers, and 4 light cruisers.

That's why it's nice to massage and see what could be interesting. Never one to envisage everything in the pot, as it's always a juggle on availability issues and it's fun seeing what's workable and realistic from the actual units IRL. Plus if we're adding it to an AH where some of the units are already gone, say Salt Lake City lost at Kormandorski Islands or the like, then that's a factor as well. I tend to use the IRL events as general guidance to maintain an overall level of plausibility especially force levels, but as the baseline to start from and then shake the tree to see what comes out when you massage it a bit. The other thing which makes this attractive to me is that the weather issue in the Northern Pacific can be used as a plausible narrative device to nullify the greatly increased role carrier aviation had assumed. Lets us throw in a nice regression to the big-gun days whilst still preserving the historical ascendance of carrier aviation, which is now intrinsic to the pacific theatre. Agree with you about the small boys, screen is screen. That's why links like yours are appreciated. T

 

[Tangles2]

This kind of action is unlikely but not impossible. The Japanese carrier groups were tied up fighting from bases in the South Pacific, while new groups were in training. I have the impression that the Japanese carriers didn't get their air groups back till October. In fact, they were conducting operational training in the Central Pacific just before Operation Galvanic, the invasion of Tarawa. The Japanese declined to oppose Galvanic, and Attu was in a much less sensitive area than the Gilbert Islands. The IJN was saving its fleet strength for "The Decisive Battle", rather than using battleships in the hopes of gaining tactical victories.

If the Combined Fleet sailed north to oppose "Landcrab" the invasion of Attu, HYPO & OP-20-G would almost surely intercept their radio traffic deigning the IJN operational surprise. Nimitz would have at least several days to assemble more ships to cover Landcrab before the Japanese fleet could even assemble. Truk is even further from Attu than Pearl Harbor is, giving Nimitz a chance to set up another ambush of the IJN like he did at Midway.

I see reference to both USS North Carolina & Washington being in Pearl Harbor during April 1943 to upgrade radar, and for combat training. Both might still be close enough to PH during early May to be sent north in support of Landcrab. USS Essex was on her way to PH in May 43 and might be able to join the battle. I'd have to do a lot more research to find out what USN ships might be available for your battle scenario but shifting the war north like this would be a major shift in strategy for both sides.

The thing is to keep the force levels plausible at core. Could some of the aviation training be conducted in home waters, and if so what carriers and would this proximity have shortened the response time? Or if the IJN was expecting the invasion and saw this as an attritional opportunity, but short of the decisive battle. They always had plans to attrite USN BB numbers and supposed they saw this as an opportunity to put additional SS in theatre to achieve this. Also, it's also nice to retain a pivotal historic personality beyond IRL circumstances. Yamamoto is such a personality and several previous scenarios have been produced where he lived past the April ambush. It would nice to use his survival and would he have gambled more on achieving something around an Aleutian's response?

 

[Belisarius II]

So, when is this fleet going to be ready to sail? By May 22 the IJN had the 4 carriers with weak air groups, Musashi, Kongo, and Haruna, 7 CA's, and 11 DD's. The battle was over on the 30th. It will take them 5 days to get there so they have to leave by the 25th. They can't just tell the army to hold out and wait indefinitely. When are they telling the army they will be there?

 

[Tangles2]

So, when is this fleet going to be ready to sail? By May 22 the IJN had the 4 carriers with weak air groups, Musashi, Kongo, and Haruna, 7 CA's, and 11 DD's. The battle was over on the 30th. It will take them 5 days to get there so they have to leave by the 25th. They can't just tell the army to hold out and wait indefinitely. When are they telling the army they will be there?

This is why I like others to trash ideas and thrash things out as the consensus result is usually better guidance in shaping a good AU. My thoughts here always came back to the influence of weather and conditions. It makes a good case for limiting the increasing impact of aviation on a battle here, leveling the playing field shall we say. Plausible for delaying landings, possibly? Obscuring and thus enabling the approach of surface forces to cause a surface battle to result? The weather is pretty bad for a period of months so it can be a plausible factor to facilitate a number of possible threads, and we can massage a number of possible scenarios and force structures and timelines covering the extended poor weather period. Look at the success of the Japanese evacuation of Kiska and the climatic conditions that underpinned that, fog, blizzards, etc, and the battle of the Pips is almost surreal and is an indication of how even radar wasnt a magic wand given the location and climate. The fact that this too was one of the first large-scale amphibious operations of the Pacific campaign resulted in learning a great many lessons subsequently employed. Also if you read some of the literature then inexperience and poor preparations for the climate were also a factor in the US army operations. My ideas tend towards limited aviation success due to the weather, possibly the training force of IJN carriers with low-experience air groups, and them targeting the ships of the landing force with some success, limiting the scope of land operations and dragging it out. That also allows for some development of those IJN air assets in that they are not totally trashed at this stage and can still be employed in a later Mariana's style continuation. A good plausible surface action BB vs BB would be nice. I'd love to wargame out say Musashi and Nagato and possibly the two Haruna's against a couple of the US standard class with the backing of say one or two of the Modern USN BBs. Still feasible and fun for all the battleship traditionists and not uncharacteristic of the decisive battle doctrine of the IJN. I think that it's going to be a USN win, but I can see the IJN trying to attrite USN BBs as a limited objective for such an operation, and it's a fun 'what if' if we can make it realistic. Also, the employment of the SSs for both sides and their roles and impact would be a good study.

 

[Tangles2]

So, when is this fleet going to be ready to sail? By May 22 the IJN had the 4 carriers with weak air groups, Musashi, Kongo, and Haruna, 7 CA's, and 11 DD's. The battle was over on the 30th. It will take them 5 days to get there so they have to leave by the 25th. They can't just tell the army to hold out and wait indefinitely. When are they telling the army they will be there?

What if the carriers had been training out of Hokkaido? One to two days are saved for a limited air strike on the assault forces before they are fully unloaded, and drawing out the land portion of the campaign. Not the air defence of later battles and the attack not fully pressed as the IJN is aware of the limitations of the aircrew. With that delay the IJN BBs sortie heading north to finish the job, coincidentally the signals int enabled the despatch of the BatDiv from PH. Thus carriers marginalised by weather and the IJN surface force attempts to destroy the landing support forces say 28th. You end up with two roughly equal in numbers groups of BBs, trying to attack in short daylight conditions and blizzards (thinking Pacific North Cape on a larger scale) fun, fun, fun.

 

[Belisarius II]

What if the carriers had been training out of Hokkaido? One to two days are saved for a limited air strike on the assault forces before they are fully unloaded, and drawing out the land portion of the campaign. Not the air defence of later battles and the attack not fully pressed as the IJN is aware of the limitations of the aircrew. With that delay the IJN BBs sortie heading north to finish the job, coincidentally the signals int enabled the despatch of the BatDiv from PH. Thus carriers marginalised by weather and the IJN surface force attempts to destroy the landing support forces say 28th. You end up with two roughly equal in numbers groups of BBs, trying to attack in short daylight conditions and blizzards (thinking Pacific North Cape on a larger scale) fun, fun, fun.

So, you're assuming the IJN carriers were withdrawn from the South Pacific, and were training off Hokkaido on May 11th? To strike the transports they need to hit them by the 14th, at the latest so they have to leave for Attu that day. I don't think that's very realistic. It gives no time for Combined Fleet HQ to think about the situation, and plan anything out. At the time their focus was fixed on the situation in the South Seas, and the new commander in chief Admiral Koga is still just settling into his job.

 

[Sargon]

I suppose we could just go with the historical forces as initially outlined in the OP for both sides?


Sargon

 

[Tangles2]

So, you're assuming the IJN carriers were withdrawn from the South Pacific, and were training off Hokkaido on May 11th? To strike the transports they need to hit them by the 14th, at the latest so they have to leave for Attu that day. I don't think that's very realistic. It gives no time for Combined Fleet HQ to think about the situation, and plan anything out. At the time their focus was fixed on the situation in the South Seas, and the new commander in chief Admiral Koga is still just settling into his job.

This is where we need to assume how tightly you want to be constrained by the IRL timeline. Can weather be a plausible factor to delay one or the other of the windows of opportunity to make the timeframe work? Having the period March through to August pretty much winter offers the option to defer/massage dates to suit a storyline you are generating. It is after all an AU and if you decide it's workable you need a realistic narrative device and we can still massage specific dates to suit the scenario you are trying to form. The inflection point may not have to be date-specific sometimes and frequently it's a little better to be flexible there to allow for something like a realistic movement timeframe which we would be more comfortable with.

 

[Tangles2]

I suppose we could just go with the historical forces as initially outlined in the OP for both sides?


Sargon

That's not necessarily so. For example, I'd also consider possibly altering the movements of the Mutsu for inclusion as an example. Nothing then was striking in her operational movements in the April onwards period IRL, and she would be lost in the magazine explosion in September, If you wanted to include her in the IJN lineup she would be good, as you could write her in as a battle loss from our notional battle, and still be able to realistically include retain the other IRL hulls for subsequent scenarios if you are part of a wider campaign. She just springs to mind as one BB which is available for consideration. It still comes down to plausibility and context, and if you are trying to slot it into a wider storyline. I'm using this to generate some ideas for a radically different AU, (midway far more attritional, Kormandorski Islands a sharp tactical defeat) and it naturally going to diverge from the IRL historical forces. But what this discussion generates for me is say a concept of operations I can thread in. Also, good feedback means that if nothing really seems workable then it's clearly going to indicate the idea has gone from plausible to wish fulfillment and so won't work. So yes if you can really see an adjustment to force levels chuck it up, and you might have thought of something (either good or bad) that I haven't. T

 

[Tangles2]

So, you're assuming the IJN carriers were withdrawn from the South Pacific, and were training off Hokkaido on May 11th? To strike the transports they need to hit them by the 14th, at the latest so they have to leave for Attu that day. I don't think that's very realistic. It gives no time for Combined Fleet HQ to think about the situation, and plan anything out. At the time their focus was fixed on the situation in the South Seas, and the new commander in chief Admiral Koga is still just settling into his job.

But how closely are we wed to the specific command appointments? Does Yammamot avoid the April ambush? I considered supposing Mikawa was canned earlier after Savo and his subsequent disagreements with HQ about the utility of the Guadalcanal campaign. I'd often considered supposed he'd been shunted off the CinC of the 5th (Northern) Fleet as a 'reward' for Savo and replaces Hosogaya. Angered at being sidelined is much more aggressive at Kormandorski Islands, leading to a tactical loss for the USN. Given plausibility and context, how much can we juggle command appointments? One of my favorites is having Tamon Yamaguchi survive Midway, giving you a good carrier commander if you want to slot him in later in the Pacific Campaign. So can we massage other personalities or retaining Koga comes down to how you want to shape the scenario. If you want to justify a command failing, the retaining him and blaming the failure on his just settling in makes a good plausible option if that was your intent.