AHC: Make Sealion very unlikely

[TDM]

Marinefahrpram gets designed earlier and cranked out in as much secret as possible, U-boats sink the Dunkirk rescue fleet, and magnetic mines are held in strategic reserve until the landings.

These alone bump the odds from "Battle of France goes OTL well" odds, up to simply poor as hell.


Cram most of the U-boat and E boat fleet into the channel to screen capital ships along with the Mines, and perhaps diversionary raids by the Deutschlands and Scharnhorsts, and you'll for sure have a few days to ferry shit over.

After that it depends entirely on how panicky and stupid the British become.

There were u-boats at Dunkirk (or rather there were U-boats in the water between Dunkirk and Britain because you don't actually want U-boats operating that close to a beach), and yet...

There is an attitude that U-boats are the crafty ninja's of the sea able to kill whatever they are deployed against from the safety of the sea-shadows. However this is not the case, even against slow moving civilian ships with escorts with the whole of the N.Atlantic to hide and strike them in, their rate wasn't actually that great due to limitations of payload and ability to in inflict damage. Against actual naval assets that aren't engaged in escourt duty they will do even less well. In the relatively shallow and constricted confines of the Channel, they do even less well again, against an RAF operating closely they do even less well again. There are reasons why the wolf pack's main area of operation was the mid atlantic and not close to Britain, and even then they they had a pretty bad attrition rate during the war.

So basically yeah you want to lose the U-boat fleet by all means cram them into the channel.

Mines, yeah not really first the Germans didn't have many, second the British had minesweepers. How are the Germans going to lay them? Surface minelayers? Yes please they are very vulnerable to basically everything. By air? the German air wing had limited mine layer capability. By U-boat? See above + issues with small payloads. Similar to u-boats there is I think a bit of misunderstanding about what sea mines do. They don't make great swathes of the sea impassable (especially not bits you yourself are operating in). They restrict movement and make operating more difficult (so often it's easier to just avoid them is that is operationally feasible) but they're not these immovable barriers that will protect the Germans from the RN.


You have capital ships acting as support of the invasion and running diversionary raids, how many capital ships do you actually have? Doesn't matter the RN has more, they can devote chase packs to the diversion raids if they want and still have way more than enough to deal with what's left of the KM in the channel.

The above plan will get what the KM destroyed, including the U-boats

 

[Antiochus V]

It is tough to get to a situation where the Germans could feel comfortable about launching the operation - something they reaslised at the time. I still think it would go very badly.

However here is the closest I can get

-No invasion of Norway and the Graf Spee remained in port. Thus the KM is as big as it can be, perhaps if we are generous there a couple of extra destroyers giving the KM 30 destroyers plus the modest number of cruisers. I don’t know how many torpedo boats they had, or how effective those would be?
-The RAF could have made an error such as pulling back from the South East in early September under heavy pressure from the Luftwaffe bombing airfields, as a consequence the RN presence of large ships in Portsmouth would have to reduce. This would reassure the Germans that they have a few days of control of the channel. The Germans having overestimated enemy losses would not realise how quickly the RAF would recover.
-Germany needed some crude landing craft and vehicle transporters, hard to see why they build them, but I understand a problem with barges was getting them off the beach again quickly enough.
-A diversionary effort in the North Sea by most of the larger KM ships and transports combined with attempting to pin the Royal Navy in port with U-boats and air dropped mines sounds on paper like a possible plan.
-The theory of a minefield in the channel sounds good on paper, though I wonder about currents and the practicality of laying it and protecting it.

The above sounds good on paper...

-I think I read it would take a week to lay a large enough minefield in the channel, but this probably assumes a lack of interfering minesweeping by the Royal Navy. Given the large numbers of minesweepers available I assume the minefield would quickly have relatively safe routes through it.
-In practice I think the Royal Navy would have expected the U-boats to deployed either in the channel or outside its main ports, so I assume they would have used many small boats to clear the area, and then been able to safely get into action in the North Sea within a day.
-I don’t see how the KM could protect the flotilla of barges and landing boats from a the assorted destroyers and small boats attacking at night. They could hug the English coastline, where the Germans would struggle to lay mines owing to coastal guns.

Thus at best I see the Germans making it ashore at heavy cost, and owing to the early and mounting shipping losses unable to manage much of the planned later waves. At best they manage to keep the supply lines open for 48 hours before it all goes horribly wrong.

 

[Aber]

Thus at best I see the Germans making it ashore at heavy cost, and owing to the early and mounting shipping losses unable to manage much of the planned later waves. At best they manage to keep the supply lines open for 48 hours before it all goes horribly wrong.

And this provides a further dilemma for the Germans - the more successful the initial wave, the higher their eventual losses will be.

 

[Astrodragon]

Marinefahrpram gets designed earlier and cranked out in as much secret as possible, U-boats sink the Dunkirk rescue fleet, and magnetic mines are held in strategic reserve until the landings.

These alone bump the odds from "Battle of France goes OTL well" odds, up to simply poor as hell.


Cram most of the U-boat and E boat fleet into the channel to screen capital ships along with the Mines, and perhaps diversionary raids by the Deutschlands and Scharnhorsts, and you'll for sure have a few days to ferry shit over.

After that it depends entirely on how panicky and stupid the British become.

Geez...

(1) When are these hordes of landing craft 'cranked out'? and what isn't getting built because of their steel allocation?
(2) In secret. Yeah. If its before the war, little to no chance - RN Intelligence had basically pwnd german naval shipbuilding - it was important to them.
(3) The Germans used U-boats at Dunkirk, they didn't do much. Where are all these extra U-boats going to come from, and where are they going to operate? (hint - you cant operate submarines too close together)
(4) I'm confused as to where these magnetic mines are going to be laid, and by what? After all, the LW has a few other things to do than drop mines, and the invasion area isn't exactly u-boar friendly.(another hin, a lot of it is the RN's pre-war antisubmarine training area...)
(5) Again, using the U-boats in the channel is, shall we say, contra-indicative to a long life for the U-boats. E-boat fleet? It was already allocated, wasn't that big, and the E-boats main weapon is surprise - using it pinned down defensively is a good way to a short life.
(6) Those would be the capital ships that were being repaired after Norway, right? They aren't actually available.

Damn, the Zeppelins made more sense.

 

[Astrodragon]

It is tough to get to a situation where the Germans could feel comfortable about launching the operation - something they reaslised at the time. I still think it would go very badly.

However here is the closest I can get

-No invasion of Norway and the Graf Spee remained in port. Thus the KM is as big as it can be, perhaps if we are generous there a couple of extra destroyers giving the KM 30 destroyers plus the modest number of cruisers. I don’t know how many torpedo boats they had, or how effective those would be?
-The RAF could have made an error such as pulling back from the South East in early September under heavy pressure from the Luftwaffe bombing airfields, as a consequence the RN presence of large ships in Portsmouth would have to reduce. This would reassure the Germans that they have a few days of control of the channel. The Germans having overestimated enemy losses would not realise how quickly the RAF would recover.
-Germany needed some crude landing craft and vehicle transporters, hard to see why they build them, but I understand a problem with barges was getting them off the beach again quickly enough.
-A diversionary effort in the North Sea by most of the larger KM ships and transports combined with attempting to pin the Royal Navy in port with U-boats and air dropped mines sounds on paper like a possible plan.
-The theory of a minefield in the channel sounds good on paper, though I wonder about currents and the practicality of laying it and protecting it.

The above sounds good on paper...

-I think I read it would take a week to lay a large enough minefield in the channel, but this probably assumes a lack of interfering minesweeping by the Royal Navy. Given the large numbers of minesweepers available I assume the minefield would quickly have relatively safe routes through it.
-In practice I think the Royal Navy would have expected the U-boats to deployed either in the channel or outside its main ports, so I assume they would have used many small boats to clear the area, and then been able to safely get into action in the North Sea within a day.
-I don’t see how the KM could protect the flotilla of barges and landing boats from a the assorted destroyers and small boats attacking at night. They could hug the English coastline, where the Germans would struggle to lay mines owing to coastal guns.

Thus at best I see the Germans making it ashore at heavy cost, and owing to the early and mounting shipping losses unable to manage much of the planned later waves. At best they manage to keep the supply lines open for 48 hours before it all goes horribly wrong.

Not taking Norway? Well, that will make the allies happy.
Sure, the KM surface fleet will be larger. But they are still heavily outnumbered - in fact, since they have to force battle somewhere north of the channel, it likely goes a lot worse for them - the RN now have more air cover closeby, the KM needs air defence (or they get to play with the FAA as well), its a bad area for subs (benefitting the RN).
The RN could have pulled further back, but it wouldn't make much difference. Another few hours sailing at best. And that's assuming they didn't do something like camouflage smaller craft like destroyers.
A diversionary strike in the North Sea just meets a superior RN force while the other heavy ships steam happily south.

Your right, it sounds good on paper, problem is the RN were operating on water

 

[RodentRevolution]

It is tough to get to a situation where the Germans could feel comfortable about launching the operation - something they reaslised at the time. I still think it would go very badly.

...


Thus at best I see the Germans making it ashore at heavy cost, and owing to the early and mounting shipping losses unable to manage much of the planned later waves. At best they manage to keep the supply lines open for 48 hours before it all goes horribly wrong.

Depending on source it looks like the 21st September was the point OTL when the KM realised they could no longer tolerate any more losses to their assembled transport assets.

69) The need for extending the transport area had shown itself to be urgent. Of the total number of vessels that had been prepared for the operation the following had been either lost or damaged through enemy action by the 21st September:
Of the 163 transports(700,000 G.R.T) - 21 lost or damaged (= 12.5%).

Of the 1697- barges - 214 lost or damaged (= 12.62%)

Of the _360 tugs, - 5 lost or damaged (= 1.4%).

Thanks to the careful planning of the Naval Staff, these losses could actually be replaced from reserves, but any further losses could not have
been dealt with in this way.

From
German Plans for the Invasion of England, 1940 Operation "SEALION"

This of course is losses endured in the embarkation ports by unladen vessels with maximum flak protection, you can expect the losses to air attack among laden vessels wallowing off the invasion coasts without flak cover and the RAF Bomber Command assets able to make multiple sorties a day due to the shorter flight times would have been magnified exponentially.

 

[Antiochus V]

Geez...

(1) When are these hordes of landing craft 'cranked out'? and what isn't getting built because of their steel allocation?
(2) In secret. Yeah. If its before the war, little to no chance - RN Intelligence had basically pwnd german naval shipbuilding - it was important to them.
(3) The Germans used U-boats at Dunkirk, they didn't do much. Where are all these extra U-boats going to come from, and where are they going to operate? (hint - you cant operate submarines too close together)
(4) I'm confused as to where these magnetic mines are going to be laid, and by what? After all, the LW has a few other things to do than drop mines, and the invasion area isn't exactly u-boar friendly.(another hin, a lot of it is the RN's pre-war antisubmarine training area...)
(5) Again, using the U-boats in the channel is, shall we say, contra-indicative to a long life for the U-boats. E-boat fleet? It was already allocated, wasn't that big, and the E-boats main weapon is surprise - using it pinned down defensively is a good way to a short life.
(6) Those would be the capital ships that were being repaired after Norway, right? They aren't actually available.

Damn, the Zeppelins made more sense.

I find the mines question interesting, I have read they needed around 7000 to cover both sides of the invasion route, but I struggled to find out how they would be laid or exactly where. I don’t even know if they were actually available.

I do think the Germans would have had quite a few minelayers - a consequence of the pre-war expectation of needing to lay and maintain various minefields along their coastline. That said I doubt they anticipated their minelayers operating in contested waters, I assume the small boats on patrol, coastal guns and their radar in places like Dover would have made it very tough to lay mines near the British side of the English channel.

 

[Antiochus V]

Depending on source it looks like the 21st September was the point OTL when the KM realised they could no longer tolerate any more losses to their assembled transport assets.

69) The need for extending the transport area had shown itself to be urgent. Of the total number of vessels that had been prepared for the operation the following had been either lost or damaged through enemy action by the 21st September:
Of the 163 transports(700,000 G.R.T) - 21 lost or damaged (= 12.5%).

Of the 1697- barges - 214 lost or damaged (= 12.62%)

Of the _360 tugs, - 5 lost or damaged (= 1.4%).

Thanks to the careful planning of the Naval Staff, these losses could actually be replaced from reserves, but any further losses could not have
been dealt with in this way.

From
German Plans for the Invasion of England, 1940 Operation "SEALION"

This of course is losses endured in the embarkation ports by unladen vessels with maximum flak protection, you can expect the losses to air attack among laden vessels wallowing off the invasion coasts without flak cover and the RAF Bomber Command assets able to make multiple sorties a day due to the shorter flight times would have been magnified exponentially.

Did the RAF plan to attack the invasion fleet at night as well as daylight attacks, or is that too impractical?

 

[steamboy]

Laying 14000 mines in the channel would basically require the RN and RAF being far too busy sodomizing themselves with cricket bats to actually fly or patrol the sea.

Did the RAF plan to attack the invasion fleet at night as well as daylight attacks, or is that too impractical?

If the Germans were sending across an invasion fleet, the RAF would have been attacking it day, and night probably with damn near anything and everything that could fly whilst the RN would have also been sending the ships in the area into the melee. An invasion is a battle for national survival, you don't hold back in that.

 

[TDM]

And this provides a further dilemma for the Germans - the more successful the initial wave, the higher their eventual losses will be.

Yep good point, it would also be interesting to see how Hitlers personality, general devotion to Storm trooping ubermensch 'it worked in Poland and France', and the sunk cost fallacy would cost Germany here.

I guess what limits the potential overall loss is that they will simply run out of ways (no matter how impractical) to get any Soldiers to Britain.

 

[RodentRevolution]

Did the RAF plan to attack the invasion fleet at night as well as daylight attacks, or is that too impractical?

Impractical was not a word that occurred in counter invasion planning, for example Operation Banquet whereby Bomber Command would take charge of everything that could fly and drop some kind of bomb that was not already in Fighter Command was simply eyewatering.

 

[RodentRevolution]

Laying 14000 mines in the channel would basically require the RN and RAF being far too busy sodomizing themselves with cricket bats to actually fly or patrol the sea.

On the 10th August the Naval Staff noted in its war diary: "Preparations for SEALION, particularly mine clearance, are being affected by the inactivity of the Luftwaffe, which is at present prevented from operating by the bad weather, and that for reasons not known to the Naval Staff, the Luftwaffe had missed opportunities afforded by the recent very favourable weather. As the Fuhrer does not wish to decide ..bout SEALION until least eight to ten days after the commencement of the Luftwaffe's major air attacks, there is already some danger of the date being affected."

Again from German Plans for the Invasion of England, 1940 Operation "SEALION" linked above. There is more but basically the Kriegsmarine became very disheartened with the lack of effort being made by the Luftwaffe to counter Coastal-Command bombers and minelayers which were compromising the Germans own counter-mining operations. Remember there were already fields of British contact and command detonated mines off the coasts by the fall of France.

 

[DDM]

As previously mentioned have the French Fleet join the Axis but have Spain join as well to start siege of Gibraltar. (Mainly to distract as combined French and Italian fleets run past the Rock.) French and Italian fleets run past Gibraltar at night and head to Brest to ready for the invasion. Now have force of ships from France, Italy and Germany that matches up against the Royal navy as approximately equivalent in heavy cruisers, 50% strength of Royal navy in light cruisers, 67% of Royal navy in destroyers, and 50% in Capitol ships. Not saying equivalent quality of ships and crews and certainly not in working together. Of interest is the combined submarine fleet of 180 submarines. Obviously the biggest ASB is having the French join the Axis but challenge was to make Sea Lion less impossible.

 

[steamboy]

Very true RodentRevolution. Basically no matter how you look at it and what changes you make, without going full ASB or having the RN and RAF sink their ships and blow up their planes 'because'. Sealion as it stands was basically impossible and would have not succeeded. And going back to the 30's or 20's makes the PoD diverge wider and wider, sure you've now got 200 LSI and 150 LST and a decent screening force of Warships to screen them. You've now also not got enough strength in Panzers and artillery to conquer France because all your steel is tied up in warship and sub production. and so on and so on.

Basically its not going to work short of magic or demonic intervention. So let this just

This isn't even reshuffling the deckchair's on the titanic. This is thinking about fire prevention aboard HMS Hood as the magazine erupts.

 

[DerWonderWaffles]

The problem with building landing craft is that it will alarm everyone in the baltic and make the UK narrow its eyes. Also the Germans would have to be prescient.

Germany is a land power (largely) and its got France and the Low Countries to the West and Eastern Europe and the Soviet Union to the East. Building landing craft pre-war serves what purpose? The Germans are not going to carry out a landing on the French coast because Denmark, Holland and Belgium are kind of in the way first. They can't launch an attack directly at France because Maginot Line shaped shredder is sitting there. So they HAVE to attack the low countries.

Can you prove me to that the British will even know? Because the historical precedent Oslo Report says otherwise.

The Germans don't need to know about the outcomes of the future to know to build landing craft. They can build landing craft for an invasion of the Soviet Union regarding the Baltic Sea and the Black Sea. Also it is not difficult for them to hypothesize such possible amphibious operations going on in the the Mediterranean. In the wiki link, I provided, it showcases it was designed as such.

But then they also HAVE to know that Sickle Cut WILL work and won't be the huge throw of a dice that it was. And then they also have to know that Belgium and Holland will fall and the British army will loose most of its equipment and withdraw and so on and so on, and again this requires prescience or future knowledge. We can write 'if they armed them with Fruit cakes then sure! it would have worked!' because we have nearly 80 years of knowledge on the War and can write with hindsight. At the time, they couldn't know that all this would work, all this would happen and so forth.

Why do they have to know? You never specified here. I already provided that Germany building landing craft isn't at all for Sea Lion. They can speculate in terms of invading the Soviets off of coasts, just as they did in OTL, if you read my link, and hypothetical Mediterranean operations. I'm sorry, but your fruit cake quote seems incoherent to the post at hand.

They also HAVE to know that upon seeing these ships or learning of them that you're building pre-war for NO reason, that the UK won't get its knickers in a twist and trying to go to Sweden, Finland, Norway and Denmark and the UK as well as Estonia etc and say "Yeaah they are...car...ferries..armed to deal with..Pirates in the Baltic?" isn't going to fool anyone.

So pre WW2 the Germans have to know exactly what is going to happen in the future in regards to OTL, and that once France has fallen in a shockingly fast period of time, (which they couldn't have counted on) and have a stockpile of ships built for landing troops built up and hanging around without a purpose for years as well as learning how to use them, getting practice in Beach landings etc. Again, for NO REASON WHAT SO EVER! HONEST!!! Whilst everyone else ignores these ships and just carries on exactly as per OTL.

Prove it. You made the claim. I already provided a link for the historical precedent of the Oslo report. You see, with the landing craft. They can hide them in Germany. They managed to move around 2000 barges, which weighed heavier and were larger than the landing craft I proposed. Britain hearing upon such advancements a scientist made, just scoffed it off. Germany can train with such crews off the coast and then push such barges back inside the country. It doesn't have to be by the coast as subs, destroyers or BBs are.

Still have to prove how Germany has to know the future, when I explained they don't. There is nothing to suggest they cannot train amphibious forces for such assaults around Europe besides England.

this is where improving upon sealion basically falls apart. Sure you could have the Germans build up a HUGE amphibious force from the mid 30's onwards, complete with a simple LST and all the shenanigans, and have them practice landings until they feel confident with them. At which point the UK is going "Okay..why are you doing this?" that panicked sweat you can smell is Norway, Sweden, Denmark and Finland shitting collective bricks, whilst France is happy with you diverting all these resources into something that won't affect them in any way, shape or form. And then you've got to get the countries that would be attacked by Germany to not just lick the lead paint, but grind up pure lead and start snorting it by the metric fuckton and have them do noooooooooooooothing.

Changing X to improve Y will affect A, B, C and R.

Carrying out a seaborn invasion isn't just a case of

A - Load men into boats
B - Land men on beach.
C - Gott in himmel!
D - Victory!

Its why a lot of techwanks unless done right are just sigh worthy, especially when you try to pass it off as being not ASB.

Sorry but to me your post is falling apart. Your swearing and sarcasm really is not helpful. I never claimed Sea Lion could succeed. Just as if you read my post. I know they need anti shipping training and a large navy to do so. Again the Osle report. The Germans can train off the beaches on the Baltic Sea.

Can you again explain how they will know about the landing craft? When Germany can hide it inside the country, unlike the ships again, which are in port.

Landing crafts are NOT the equivalent of tech wank. This isn't a case of Germany having to build technology. It is a case of building a ship designed to land the beaches and return. Not rocket science. German engineers can handle it, as evidenced by OTL when they made the Marinefahrprahm. Unless you can prove its techwank, since you made that claim first.

"In 1937 the Germans decide to build the VK*insert number and letter here* as their main tank with a long 75mm gun at first with others having the 88mm gun arriving in 1939!"

"Okay, what's the driver for this? Why have they gone from the Panzer 3 and its 37mm gun which was the main tank of the Panzerwaffe to this, by the standards of the times HUGE tank, that's massive overkill?"

"Because!"

"No, sorry old chap, going to need more than that."

"Just because okay!"

They won't just go "Hey we need a tank that looks suspiciously like a tiger II." for no reason in the 30's there simply wasn't a need for such a monster, the Panzer III was one of the worlds better tanks at the time There's simply no need to suddenly disrupt their production schedule and make a massive new tank with a gun thats so absurd overkill against its opponents that its almost comical. To do something like a "We need an amphibious assault craft!" you need a 'driver', something that pushes it forwards. And unless you know that France and the Low Countries is going to fall in 6 weeks, you don't divert resources to something that might well worry some neighbours and also tip off your opponents.

They build such landing craft training ambiguous forces for potential operations involving the Baltic sea and the Mediterranean. That is why. That is not hindsight. Plausible decisions for their preparations of war. Just like when they created armies and build tank factories.

Not sure why you brought in a tiger II, as it has nothing to do with the landing craft. Also, the resources to build the Marinefahrprahm can be the Graf Zeppelin aircraft carrier, along with the Bismarck and Tirpitz battleship. Germany can make a decision not make such ships as they are aware they are a land power and would be better suited for another way to provide logistics for the army.

If you want a good example of a story that is basically a bit of a tech wank but without it being a "JAH! ALL OVER MY FACE!!!" tit job from Guderian and co, have a look at

https://www.alternatehistory.com/forum/threads/ahc-peerless-air-ministry.445025/

Here the tech changes are within the constraints of reality and without it being a blatant wank. That's how you make a story work. Its not a case of "Suddenly the RAF has Hawker Tempest II's in 1939 waiting for the Luftwaffe!" the changes are within reason, and are beset by problems in training, production etc. Stories like this are how you do a decent tech change/improvement. Also see

https://www.alternatehistory.com/fo...-reap-the-whirlwind-story-only-thread.343760/

As a tour de force in how to do a tech change story well. Because even with the main character being a man who has our level of hindsight, he runs into the realities of things, industrial problems, beuaracratic obstructionism etc, poor leadership and management etc etc. And the battles to get things done and changed which he knows WILL work, are often struggles against the most bitter of opposition.

The Germans suddenly building landing craft, in the baltic, in the 30's literally makes NO sense. Who's your target? Why are you wasting resources on them on the off chance that when you beat france you can threaten the UK that you can't possibly know will happen without hindsight or being able to see the future.

Well thanks for the links, but again they don't have any relevance to the topic. You still have yet to prove how it was a techwank. Landing craft are helpful in providing logistics and supplying forces by water, whether doing so by land may be unavailable to little/no railroads to support assaults of any area by coast.

 

[steamboy]

Yes and those landing craft are going to be so useful heading through the ardenne and the like. Whilst they might be useful in hitting Denmark it would probably be a tad brave to sail them off to Norway beyond the narrow bit between Denmark and Norway but thats about it.

hypothetical scenario for you. You are now a chap in Germany and pushing for the construction of landing craft, its 1937, you're in the Kriegsmarine, so the poor 3rd son of the German armed forces.

You don't build these ships unless its for a purpose. As I said, Germany's a land power, and its got its rivals on its land borders to the East and West. The Germans are not going to launch an attack at the Maginot line, even if they could breach it (and I don't doubt they could, just with one hell of a butchers bill)if they can't help it, so that means going round it.

So you build these landing craft for what? Your enemy is France and Poland. Sure you could do some landings on the baltic coast but unless you plan on invading Denmark too, you can't get your landing craft round to France as there's a fair bit of sea, Denmark, Holland, Belgium, the Marine Nationale and the RN in the way and a gaggle of assorted airforces.

So why are we building these ships that we can use in very specific circumstances again? Yes they can help with logistics. Won't help much in the Ardenne or Belgian/Dutch interior. They could be useful hitting Denmark or the southern part of the Norwegian coast. But do we know that we -are- for sure going to go after those countries? Norway's neutral with a partially friendly government thanks to the Quislings. Denmark's hardly a threat and there's not much there worth invading. The Swedes have a potent cost defence force and small army but are quite friendly. So why should we waste material based on the off chance we might go to war with these?

This is what a driver is. Something that pushes forwards something to get built or to change something. What's the driver to waste needed resources on a large number of amphbious craft without knowing that France and the Low countries is going to fall in 6 weeks? You need to build enough of them to make Sealion be a bit better, but without knowing FOR SURE that this resource cost and investment will pay off in the future, its just sunk costs and resources that are needed elsewhere.

And whilst these ships might be useful for an invasion of the UK, why would we waste resources on building potentially hundreds (or even a thousand) of ships that may or may not be used for any major role, we don't need 2 - 400 landing craft. Yes we could threaten England, but we do not know how long any offensive into the Low Countries and France will take, our losses etc. Yet you want us to build hundreds of ships for an invasion that might not happen, when we need the resources and the personnel elsewhere? And as for helping with logistics, yes, in very limited areas. Nothing that will matter in the most important in the actual battle for France.


____

Thats the problem. The Germans do not know that sickle cut is going to work. So there's simply no need to have a large number of dedicated landing craft because whilst a few score might be useful. You're going to need a damn sight more than that to do anything Sealion shaped. And until then, this mass of boats are ships without a role, that have sucked up resources and money that's not infinite. You'd also have to get the Heer onboard to actually plan something like an attack and assault landing otherwise you've got a lot of boats with no experience in landing outside of trying to treat it like a river crossing.

Yes the Germans could build these boats, but WHY would they? Thats the big issue. To have enough useful craft to make Sealion more effective than a barge loaded farce, you'd need scores and scores of these ships, hundreds of them, built pre-war and with experience in actual landings by working with the heer to figure out what works and what does not because there's a whole difference between pootling up to a beach and landing against opposition whilst under attack from the air and sea. So you need to train. And no matter how good you are, this is going to be spotted. And the German military practicing large scale landings on beaches with air support and warships...why are they doing this? What's this for? Lets look deeper shall we? Considering how shit the Abhwehr was at its job (with many folks who were or probably were actively colluding against the Nazi's even though they were Germans) I doubt they would do a great job of keeping other interested countries spy's away. Or would be effective at not 'accidentally' giving them info straight up.

Stuff don't happen in a bubble, and this would be noted, and the Allies pre war were thick, but they are not dumb, there's a difference.

And again, you're building an invasion force, training for it, for an invasion you have no way of knowing will be able to go ahead. You don't know sickle cut is going to work (hell neither did the Nazis, it was a huge gamble) so why waste resources when you need them on something that may or may not happen save having them for possible operations along the Danish and Norweigan coast as well as possible efforts on the Dutch coat, there's no need for hundreds of them unless you're planning for the Invasion of England, before France has even fallen and you don't know for sure if it will.

Whilst landing craft are not your typical German tech wank, they are still a common sealion problem. You've got to build enough of them to make it work. You've got to train to use them and train your units to use them to make it work. You've got to do this pre war and you need resources for everything else too and can you afford to spend the resources building them, especially in the numbers you're going to need. And what if they are noticed. And they probably will be. Then what? Whats the UK's reaction, because again, thick but not dumb. The Admiratly might very well figure out that these landing craft, all the training for it points to planned future operations against friendly countries or even the UK itself.

Do they then go humper dumper didio and resume the aforementioned cricket bat sodomizing? because they are not going to ignore this, which would probably be needed.

You can't just go "The germans build landing craft, there done." because it all has a knock on effect. You've got to build them, what does not get built instead, you've got to crew them, what does not get crew instead, its all domino's that have to fall into place.

Baltic sea....

Okay makes sense here, probably the only real place they might be useful.

..and the Mediterranean

ummm...*glances at a map*

Just making sure there wasn't a German Med coast I wasn't aware of. Again, future knowledge is needed to know that the italian buffoon is going to get you involved down there when you go to pull his bald arse out of the fire.

Also, the resources to build the Marinefahrprahm can be the Graf Zeppelin aircraft carrier, along with the Bismarck and Tirpitz battleship. Germany can make a decision not make such ships as they are aware they are a land power and would be better suited for another way to provide logistics for the army.

Interesting but the costs for these had already been done and paid for and the resources put aside with the ships well under construction. So how far back are you going to go to have this happen? and that screaming you just heard is the German Admiralty howling for your blood for daring to try and cancel their darlings. And the Furher was supportive of the Z plan of which those three ships are vital components of.

But now we know for sure that they are useless? How? No battleship has been sunk from the air, and we can use our vessels to disrupt the British should we go to war with them. And we need to answer the French battleships lest we leave our coast undefended. And if you want to build your invasion craft, will they not need artillery support or protection from other warships and is the Battleship not the best method for this?

 

[TDM]

...



Prove it. You made the claim. I already provided a link for the historical precedent of the Oslo report. You see, with the landing craft. They can hide them in Germany. They managed to move around 2000 barges, which weighed heavier and were larger than the landing craft I proposed. Britain hearing upon such advancements a scientist made, just scoffed it off. Germany can train with such crews off the coast and then push such barges back inside the country. It doesn't have to be by the coast as subs, destroyers or BBs are.

Still have to prove how Germany has to know the future, when I explained they don't. There is nothing to suggest they cannot train amphibious forces for such assaults around Europe besides England.

1). the barges were pre-existing civilian tech, we knew about them it just we knew about them as river barges used to transport goods about. The fact the German were going to repurpose them as trans channel landing craft didn't make them secret, it made the Germans desperate. Because they were not fit for the purpose, and in doing so they would have lost a good chunk of their economic transport infrastructure as well as assault troops.

2). Once they started collecting them and moving them around the Brits did notice and lo and behold they ran RAF missions against them. Because firstly you can't hide 2,000 barges (especially in conquered territory), and secondly no one is fooled for why they might be being massed in Dutch and French ports

.Sorry but to me your post is falling apart. Your swearing and sarcasm really is not helpful. I never claimed Sea Lion could succeed. Just as if you read my post. I know they need anti shipping training and a large navy to do so. Again the Osle report. The Germans can train off the beaches on the Baltic Sea.

Can you again explain how they will know about the landing craft? When Germany can hide it inside the country, unlike the ships again, which are in port.

Landing crafts are NOT the equivalent of tech wank. This isn't a case of Germany having to build technology. It is a case of building a ship designed to land the beaches and return. Not rocket science. German engineers can handle it, as evidenced by OTL when they made the Marinefahrprahm. Unless you can prove its techwank, since you made that claim first.

You keep citing the Oslo report but I'm not sure why as you seem to be using it as proof that the Germans can hide what ever they like? The Oslo report would seem to prove the opposite, that actually the Germans weren't great at keeping secrets! The reason why the british Intelligence dismissed it was basically because it was such a huge breach in security (it looked too good to be true, and Intelligence folks tend to be suspicious old souls). In reality such intelligence tends to come from multiple sources. And yeah basically it's gong to be very hard for Germany to hide the manufacture of such number of landing craft. Especially once people start fleeing Germany and the German starts invading it's neighbours.

The techwank issue isn't about "is designing and building a landing craft within the wit and ken of German ability"? Of course it is. It's can they produce and hide the numbers required to be useful and still do everything else when resources are very, very tight. and if they don't get their battle of France success it's all academic because they won't be launching sealion from the german baltic coast. The German Techwank defence is basically "because of amazing German technological wizardry and efficiency" Germany can pull out of it's ass what ever is required to make things work,

I.e. that Nazi germany is a weird hybrid of Mr. T and MacGyver.

.They build such landing craft training ambiguous forces for potential operations involving the Baltic sea and the Mediterranean. That is why. That is not hindsight. Plausible decisions for their preparations of war. Just like when they created armies and build tank factories.

Not sure why you brought in a tiger II, as it has nothing to do with the landing craft. Also, the resources to build the Marinefahrprahm can be the Graf Zeppelin aircraft carrier, along with the Bismarck and Tirpitz battleship. Germany can make a decision not make such ships as they are aware they are a land power and would be better suited for another way to provide logistics for the army.

Really what amphibious landings on the scale of a "Sealion" were the Germans obviously going to do in the Med & Baltic? (not that Britain would be "Ah Ok the Med you say? Yep that's fine we have no interests tied up there") either way it doesn't matter. Because even if you say "er yes those are all for taking those Estonian islands* again", the capability is what matters, and yeah you can be sure that if Germany suddenly develops the ability to land a significant armed forces over water Britain will be very interested.

Britain you know the island off the coast of Continental europe that's been using water and a massive navy as a defence and has been thinking in terms of a continental invasion on it's shores, with military planing and spending based on not letting that happen, that Britain.

The point about the Tiger 2, is that technology is decided upon and developed subject to evolving needs from a series of situations at the time. I.e the Nazi's upon coming to power in 1933 didn't say "aha our dreams of building an underpowered 68 tonne monster tank can finally begin", the perceived need for the Tiger 2 came out of years of warfare and development in tanks and tank doctrine, and the restrictions of the German military infrastructure and military thinking at the time.

So again the question is not can Germany in theory build a fleet of 1000+ landing craft capable of crossing the channel and start doing so at some point far enough back to ensure they're ready for 1940, it's why would they decide to at that point that is far enough back to give them enough time to do so. Especially when as per above realigning those resources not only limits their other options meaning they're less likely to be in a position in 1940 to use them, but also makes it harder to play political "I'm not touching you, I'm not touching you" in the 30's.

As to stealing the steel from Tirpitz etc. Yeah Ok, only you don't just mount a seaborne invasion with landing craft, you going to need to protect those landing craft from the RN, so yeah given the KM was out gunned by the RN in pretty much every area you going to need more KM in other areas as well.

And that's the inescapable issue**, because you have to go over the channel to do sealion and because that means dealing with the RN (and RAF), and the RN has basically more of everything compared to the KM, the KM doesn't just need more landing craft, it needs more of everything to stop the RN from sinking all it's landing craft.



*and since Britain and Germany are not the only interested parties here, I think Comrade Stalin might have an issue with that, i.e the butterflies are unavoidable.


** well one of them anyway

 

[Gudestein]

I’ll try a variant.
Inspired by this thread:https://www.alternatehistory.com/fo...-placed-in-charge.453303/page-7#post-17718958
That have the allies air drop battleships on D-Day I Will propose an alternative. A floating tugable fort to be sunk in some m’s of water.
Various guns could be used. Purpose would be to defend the beachheads from the RN having unsinkable heavily armored forts off shore from the Beach heads.
Dont Care for the pod so lets just say the nationalist capture the Spanish gold reserves so they pay for the help they got IOTL.

 

[TDM]

Also on the idea of hiding the building of a fleet of Marinefährprahm secretly in every workshop in germany to prevent the usual eyes on the boat yards from spotting them doesn't work. That's a sea going 48m boat, you are going to be limited to where you can build them (at least not without also building a bunch of secret boat building infrastructure), and you're going to need some pretty specialised resources and knowledge to actually build them, and they tend to be tied up in the preexisting ship building industry and infrastructure.

 

[Gudestein]

Also on the idea of hiding the building of a fleet of Marinefährprahm secretly in every workshop in germany to prevent the usual eyes on the boat yards from spotting them doesn't work. That's a sea going 48m boat, you are going to be limited to where you can build them (at least not without also building a bunch of secret boat building infrastructure), and you're going to need some pretty specialised resources and knowledge to actually build them, and they tend to be tied up in the preexisting ship building industry and infrastructure.

These boats were very simple and to a large degree made of concrete. The US faced the same situation with their LST needs and build them in new shipyards at rivers inland. So it is possible. The tricky thing is to prioritize it before the Fall of France.