Operation Sealion - intervention of Japanese or Italian navies.

There seems to be a consensus that Operation Sealion could never have succeeded as planned. However, would one of the two following scenarios have affected the outcome?

1) Immediately after the fall of France, Hitler secures Gibraltar by either a treaty with Franco or the invasion of Spain. The Italian navy, promised huge territorial concessions, sails the Italian navy through the Straits of Gibraltar to support the invasion.

2) Hitler promises to support the acquisition of British colonial holdings by the Japanese in the Far East. He points out that the successful invasion of England would make this task far easier for the Japanese, and that their aid is vital for the success of the operation. American isolationism is at its height. He persuades them to send their navy to support the operation.

Alan said:

There seems to be a consensus that Operation Sealion could never have succeeded as planned. However, would one of the two following scenarios have affected the outcome?

1) Immediately after the fall of France, Hitler secures Gibraltar by either a treaty with Franco or the invasion of Spain. The Italian navy, promised huge territorial concessions, sails the Italian navy through the Straits of Gibraltar to support the invasion.

2) Hitler promises to support the acquisition of British colonial holdings by the Japanese in the Far East. He points out that the successful invasion of England would make this task far easier for the Japanese, and that their aid is vital for the success of the operation. American isolationism is at its height. He persuades them to send their navy to support the operation.

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You're going to get flooded like there is no tomorrow with people saying "CANT HAPPEN!"

That being said.

By god I want to see the real world diplomatic mails that people would send if the IJN just picked everything up and set sail for france after the fall of france.

Italian navy could possibly have range to sail there, Japanese sure as hell could not. Where would they refuel? This is just the first tough question in this. Before it comes the question 'Why would Japan do this, when they obviously have some more pressing business for their fleet?'

And it is impossible, because cooperation between Axis was not that good that they could request the ENTIRE fleet be transferred to the other side of globe.

I hate to burst your bubble, but...

The IJN was barely, BARELY able to support naval forces to strike Pearl Harbor. To allege that they would be able to send them all the way to England...it's not ASB, it's a special warp of time that is BEYOND ASB.

Oh I know but we have handwavium!

Come up with interesting excuses and just focus on what would actually happen.

My TL would be something like:

Japan prepares for it for several months during the sinno-japanese war. They wont send their entire fleet but any assets that can be separated from the immediate war effort and colonial security should the allies intervene in a timely manner. The fleet brings neccesary supplies with it so that it does not require a port at any time. (the difference with this and Pearl was that they were meant to go to pearl and back and fight the way there and out. This is a one way trip to france where they will be refuelled and rearmed by the Germans, bringing supplies for a journey like this is a different matter entirely to Pearl)

It would be doable assuming the Japanese are motivated (that would be an interesting TL) Maybe they know that the war will end badly for them and think that instead of risking it on a flash attack and dig in wait for their enemies to run out of willpower, which failed historically, the japanese aim for one really quick killing move. And know that nothing else matters except the UK isles so they agree to do it.

And German historical plans pre-war include capturing gibraltar, say that the germans are QUITE insistent on this point to the point of just marching the guys over if neccesary. Franco will probably fold before that and agree to join under considerable duress but lets say that Spain and the spanish fleet is unuable but the Italian + very large Japanese taskforce are usable with a combined German and what might be usable from the French fleets Hits the UK as soon as everything is in place with a combined U boat and Luftwaffe BoB.

My bet is that the UK would hold but it would be possibly the largest single naval engagement in history.

The UK would have enough time to prepare, they wouldnt declare war on the japanese when the fleet starts moving i think, but they would follow it closely and know exactly what it was supposed to do. So the Uk would have at least a month or two assuming japanese depart when they know france falls. If so then the UK can leverage all its allies and friends for any ships, supplies and weapons that it can gather in that time. US probably wont join but the second the UK is in the best position to do so they will strike first.

So. A combined Japanese-French-Italian-German fleet battles it out in 1940 against a Combined UK-Commonwealth-Minor navy on the north sea, the winner decides the war.

If it starts to go very badly for the UK the USSR might actually join in and try to invade the Continent while it still had an outside shot of winning.

I know it takes some amount of handwavium to get the japanese to send a "large" portion of their fleet say, 2/3rds in such a move but produces an interesting alternative world.

I would have thought that the occupation of the British homeland would have made the rest of the Empire indefensible. It would also have resulted in the destruction of most of the British fleet. Would that not be sufficient motive for the Japanese, given that the Americans were not prepared to intervene at that point? Also, is there not a precedent in a fleet sailing that far in 1905?

Assuming the japanese spend about a year quietly building things up for it, they could get the fleet and the supplies as far south as southren china before the UK gets wind of whats going on enough to actually react. That would be a fleet 2-3 times larger than the Pearl fleet.

Once the UK realises that the fleet is sailing for europe, they put the two together, after vichy, germans forming near spain, Italian fleet in high prepardness and the UK army just kicked out of dunkirk.

They calculate that the Japanese navy will have to sail around africa, putting it within range of several large UK naval and aerial bases, giving the UK ample time to prepare a good set of ambushes along the way if neccesary, or simply gather intel and shadow the fleet.

If all goes well, the Italian fleet will be ready to sail out from the med to greet the Japanese fleet somewhere in the South Atlantic. The UK needs to strike before that and cripple the Japanese fleet. Then turn around and hit the Italian fleet and then turn around and defend the home isles strongly enough to prevent a Germany that decides to go "to hell with it" and invade without having air superiority.

All in all, would be a mess, but i bet UK would win.

Alan said:

Also, is there not a precedent in a fleet sailing that far in 1905?

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Coal powered fleet. And they stopped at few places to coal up. Japanese with their oil powered fleet would have no such luxury.

Shaby said:

Coal powered fleet. And they stopped at few places to coal up. Japanese with their oil powered fleet would have no such luxury.

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You can bring tankers with you and refuel underway. Its not easy, pretty or anywhere near the word covert but it can be done. And if the Japanese simply say they are conducting long term fleet exercises in the south pole for "winter warfare" the world might partially buy it.

If Japan gets involved, then the United States is probably thrown into the mix a good year and a half 'early'. With the Japanese home islands defenceless from the sea and with absolutely no protection of their supply lines for their campaign to China.

And that's assuming that they are refuelled underway by alien space bats so that they can get to Europe.

Hkelukka said:

You can bring tankers with you and refuel underway. Its not easy, pretty or anywhere near the word covert but it can be done. And if the Japanese simply say they are conducting long term fleet exercises in the south pole for "winter warfare" the world might partially buy it.

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Tankers that themselves will be consuming oil.

And winter warfare near the South Pole?

There's gullible, and then there's flat out stupid.

Serenissima said:

If Japan gets involved, then the United States is probably thrown into the mix a good year and a half 'early'. With the Japanese home islands defenceless from the sea and with absolutely no protection of their supply lines for their campaign to China.

And that's assuming that they are refuelled underway by alien space bats so that they can get to Europe.

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Prepare ahead

Bring tankers for refuel, if impossible, build tankers ahead.

Dont send whole fleet, send perhapse 2/3rd, run the remaining 1/3rd ragged while the 2/3rd is out.

Force the UK to declare war first. Officially send fleet on crap like goodwill tour or some such. Force the UK to declare war first, play it cool in diplomacy and stall and while the UK will probably strike first you can delay their response until probably somewhere in the atlantic and not the indian ocean. but it wont be pretty for the japanese when the UK retaliates, even with 1 years of preparations and tankers and food ships that they scuttle one by one as they empty the stores if neccesary the fleet will be probably the worst positioned fleet in naval history when the UK hits.

There was a thread, not that long ago, started by Archytas. He proposed much less ambitious plan for Japan and it was deconstructed in detail. There are logistical obstacles of Japan ever deploying their fleet that far. First off, they'd need to travel around Cape (either Horn, or Good Hope). That is journey of some 14-16000 miles. For ships that can barely make 5000. And even if we handwave those away, there are a lot other reasons why Japanese would feel they need the fleet a bit closer home. But read the thread I linked. It is not that long and in first four pages any notion this feat is possible will be dispelled.

PS

Once the fleet is there, how do Japanese keep replenishing it? Ships cannot sail for very long without at least some repairs, airplanes lost will need to be replaced and, worst of all, once initial complement of ammunition is depleted, where do they get additional ammo for their ships?

Elfwine said:

Tankers that themselves will be consuming oil.

And winter warfare near the South Pole?

There's gullible, and then there's flat out stupid.

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And then theres the guys that ran the US intelligence department on December 1941. I'm hoping the same guys work there.

I'm starting a new thread about this since i'll let the OP defend his idea, i have some changes i'll make so i wont derail.

Get Portugal involved and

You can refuel in Mozambique, Angola, Cabo Verde, Lisbon. Given you need Gibraltar that means Spain is allredy in and portugal would likely folow.
Last time I talked about a similar scenario (US Neutrality thread) I trew in full french cooperation, the fall of Africa in Axis hands and the RN running out of oil to make a blocklade an alternative to sealion. (And that was likened to Satan IceSkating in terms of plausabilty)
If the aim is to validate sealion, all you need (in fleet terms, there's lot of stuff that has to be solved to make the crossing possible) to the RN is to keep it away from the English Channel.
Lets say that happens east of Britain and close to Holland (the original plan for the invencible Armada).
If the blockading fleet stays within Bf109 range carriers are not needed for the job, and if you factor in the whole of the Italian and French fleets you have enouth BB to have a fight if you assume the British Med lost a few.
You only really need the IJN if you want to fight a carrier battle. So let's not bring in the whole of the IJN but only the Akagi and Kaga and a few CA and DD. They could make the move before going to war, and if nobody attacks them along the way and they bring tankers with them it can be done. Its summer of 1940, so the RN will be flying Sea Gladiators and the IJN A5Ms rather than Zeros, wich would make for beautifull dogfights. It also means that if any carrier fighters get close to land bases it would be Gladiators vs Bf109 or Claudes vs Spitfires, wich would be painfull to watch...



March 23rd, 2012, 08:32 PM
AdA
Member
Join Date: May 2011
Posts: 411


Worst case scenario
Let's go ASB to the limit. US is run by christian fundamentalists who flat out refuse any form of warfare. Russia goes a bit better than OTL. Africa falls to the Axis. The IJN rules the Pacific. With nothing to do in the Med, and after a combined german and Spanish force takes Gibraltar, the RN runs out of oil, the whole of the german, Italian, French (Vichy sided with the axis) and even a part of the IJN blockade Britain. The proud island surrenders after eating the last available turnip. Then, while the Americans pray, the whole of Europe and Japan turn on Russia. Here the bats make a low level victory roll over the Dover cliffs in a perfect diamond formation.

So, here is the idea. Didnt start a thread after all

The following 3 PoD's.

Hitler realises that after France falls the UK must be taken, or at least, it must be actually threathened with such happening to force submission. This task can not be given to the luftwaffe alone. So, as the Germans lack a navy the need a navy. They decide to prioritise taking and holding the french navy securely as quickly as possible and as much of it as possible. How much of this succeeds depends on you.

As a result of the decicion to take UK seriously in planning, the German Diplomacy focuses on allowing Spain either enter the axis, or failing that, allowing Gibraltar to be seized. Japanese and Italian nations navies are important to cross-axis coordination is better.

Japan calculates accurately but without the historical error of assuming democracies lack the will to fight, and instead, vision democracies as fanatical Ikko-Ikki type nations that will fight when there is no point when clearly the Japanese have won. So, instead of trying to win a long bloody war, it is better to strike a quick blow if possible.

Towards that end, the Japanese realise that Rather than see the US as a natural enemy, it is better to see the UK as a natural enemy, if the UK is no longer at war, the US alone is unlikely to start a new war until the UK has been handled sufficiently well and the fleet assets rebuilt or returned.

After the Fall of France the Japanese fleet, which has had roughly 2 years planning and preparing time assembles and departs for training exercises in the south indian ocean. Due to the time and effort made, the fleet has enough supplies to reach Spanish or Vichy French loyal areas to refuel on their way to the UK.

The Italian navy will join in.

But to keep it fair, you can decide if the Spanish navy joins or doesnt join.

So. After the Fall of France ,the following happens.

1: German forces advance unopposed through the spanish countryside towards gibraltar. Spain declares neutrality and proclaims that it has no military assets to stop something that both france and UK tried and didnt accomplish. So, the Spanish armies will defend the cities and let the Germans just use the transport infra, what little there is.

2: 2/3rds of the Japanese Navy, with enough supplies to make it, depart for German holdings in Europe where they will be refit and refueled for a invasion of the UK. They bring specifically anti-ship and anti-air weapons lacking all ground attack weapons on the way unless strategically beneficial, otherwise assume Germans have Japanese specs and will refit a few factories to build Japanese parts and ammo and so on.

3: 2/3rds of the Italian navy depart for German atlantic bases. Same with Italian airforce, African forces defence only.

4: BoB begins but with significantly greater intensity and focus due to longer preparations, conversly, should it fail germany is basically screwed if Su attacks.

By the time of the BoB's historical ending, the Japanese-French(what the Germans managed to salvage and use that wasnt in OTL due to ATL's focus on a quick invasion)-German-Italian navies are ready and able to strike and the Luftwaffe still has some but not much fight left in it (say about 10% better than otl)

What would happen and what would you change and do you have any interesting thought?

I think the Japanese superiority in fleet aviation would give them a decisive advantage over the British navy in any engagement in the open sea, particularly in view of the fact that British would still have to maintain sizeable detachments to defned the Med and the Home Islands. Madagascar and Dakar could have been used as staging posts for the Japanese navy, with some pressure exerted on the Vichy government. The vulnerability of the Japanese home islands would have been a largely academic point given the pitiful state of the British army at the time, and whether America would abandon its isolationism to defend the British home islands from Japan any more than from Germany is open to question. I think Axis air superiority in carrier and land-based aircraft would have been decisive in any fleet action close to the British Isles.

Think how vulnurable such a giant fleet would be to the UK using wolf pack tactics on t hem, that, or just plain ol hitting them with high altitude bombers and such from land based targets. Would mean that either the japanese take time neutralizing them or they focus on pure fighter cover while they go. Either way, assuming for the mental image of it that it actually happens, the combined UK-Axis fleet would have one of the biggest battles in history, quite a lot of axis troops would probably get ashore but the UK navy would eventually win because of home field advantage and smash the axis navies. The battle would probably last several weeks and it would decide the war then and there.

1. Diplomacy to get Spain into the scheme is, I fear, impossible. They would up the ante every time Germany gets close to the deal, until Germans give up. Majority of Spanish demands were economic and those demands Germans found impossible to accept. Quite aside from territorial demands Spain made, which were in total disproportion to her possible contribution to the war effort.

2. Where do Vichy French (who in case Spain has entered the fray would be less than eager to help) and Spain find oil to deliver to Japanese ships? None of their possessions is a net producer, nor has any significant storage of the fuel. Again, without considering the political will of either to help.

3. Once Japan fleet is in Europe, how do they replenish it? Spare parts and ammunition would be impossible to deliver. Few weeks into the fight and fleet is in the state of utter disrepair.