when was it too late for sealion if they got ashore

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nota
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when was it too late for sealion if they got ashore

#1

Post by nota » 09 Aug 2021, 23:02

when did the brits ability to defend become to much for an invasion to succeed

lets drop the they can't because of air or sea power will not let them land

and just discuss the time frame for an invasion to have a chance IF by hook or crook
they were able to put boots on the ground in the numbers needed with supply

a few weeks after Dunkirk the axis may have been able to get a sure victory
if they could move troops on shore
was that still possible by fall 1940 or even spring of 1941 ?
what and when are the tipping points where invasion is not possible to win even if the troops get across

and again yes the navy and air powers will not allow a real landing
we know and understand that point
and lots of other threads have beat that to death

so lets leave the difficulty of getting on land to other threads
and just try to discuss when the landings can't win by the brits efforts to rearm

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Re: when was it too late for sealion if they got ashore

#2

Post by KDF33 » 10 Aug 2021, 00:39

With those conditions, I'd say 6/22/41.


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Re: when was it too late for sealion if they got ashore

#3

Post by VanillaNuns » 10 Aug 2021, 00:59

Late spring or early summer 1941 (before Barbarossa)

* German forces tied up in Africa

* German forces needed for the forthcoming invasions of Greece, Crete and Yugoslavia

* German forces being deployed east in preparation for Barbarossa

Simply not enough manpower to launch Sealion with all the above in progress.

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Re: when was it too late for sealion if they got ashore

#4

Post by mezsat2 » 11 Aug 2021, 18:15

They would have to go at night, by barge and airdrop, seize and destroy the radar towers first, then the RAF fields.

French warships could/should have been seized for a one way ticket to carry troops and provide fire support.

Certainly a Pervetin operation.

nota
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Re: when was it too late for sealion if they got ashore

#5

Post by nota » 12 Aug 2021, 21:08

VanillaNuns wrote:
10 Aug 2021, 00:59
Late spring or early summer 1941 (before Barbarossa)

* German forces tied up in Africa

* German forces needed for the forthcoming invasions of Greece, Crete and Yugoslavia

* German forces being deployed east in preparation for Barbarossa

Simply not enough manpower to launch Sealion with all the above in progress.
well IF you invade and win there is no need to do the other operations as the war vs england is over
so no troops south to yugo greek or even africa unless to mop up after the fighting

and Barbarossa can wait as there is now no rush
and several years of peace would help long term on that plan

but the timing is on the english as to how fast they rearm plus draw arms and supply from the empire USA and maybe others
while the empire has the men they lack tanks and aircraft as does the USA in 1940

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TheMarcksPlan
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Re: when was it too late for sealion if they got ashore

#6

Post by TheMarcksPlan » 17 Oct 2021, 02:59

KDF33 wrote:
10 Aug 2021, 00:39
With those conditions, I'd say 6/22/41.
You wouldn't want to launch Sealion during Barbarossa but I read the ATL condition as basically removing the Channel as a constraint on the German army. If that's right, it's probably not until some point in 1943 that Sealion is too late. At any time after Barbarossa and before the Allies have large armies in Britain, sending 50-60 German divisions into Britain conquers the island. Even if Germany has to defend elastically all the way back to the 1940 border in 1942 or 43, that's certainly worth knocking out Britain. Germany can then focus 90% of its effort in the East, which is probably catastrophic for the SU even beginning from ATL 1944 (after a successful 1943 Sealion).

But of course the Channel was a real constraint and overcoming it would have required a substantial resource investment. From that point of view, the analytical question re Sealion is at what point there was no feasible path for Germany to have spare resources to invest in bridging the Channel. That's probably whenever Germany no longer had a chance to beat the SU, which I lean towards locating at some point between July 1940 and November 1941. There are reasonable arguments for a later date...

The hypo of removing the Channel constraint also illustrates a central plank of German strategy had they defeated the SU: recommit to building a credible threat of Sealion, which would tie down enormous Allied forces to protect against the catastrophic contingency of Allied unpreparedness for Sealion. This logic is implicit in Fuehrer Directives #32 and #32a, which discusses reviving Sealion to tie down British forces. The basic logic is one of internal lines: Germany can threaten a broad arc from England to northwest Africa to the MidEast on interior lines; the shipping logistics of defending against these moves simultaneously are impossible. Therefore the bulk of Allied forces would have had to defend against the catastrophic Sealion contingency and largely abandon the MidEast (at least).
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Re: when was it too late for sealion if they got ashore

#7

Post by Peter89 » 17 Oct 2021, 18:18

TheMarcksPlan wrote:
17 Oct 2021, 02:59
KDF33 wrote:
10 Aug 2021, 00:39
With those conditions, I'd say 6/22/41.
You wouldn't want to launch Sealion during Barbarossa but I read the ATL condition as basically removing the Channel as a constraint on the German army. If that's right, it's probably not until some point in 1943 that Sealion is too late. At any time after Barbarossa and before the Allies have large armies in Britain, sending 50-60 German divisions into Britain conquers the island. Even if Germany has to defend elastically all the way back to the 1940 border in 1942 or 43, that's certainly worth knocking out Britain. Germany can then focus 90% of its effort in the East, which is probably catastrophic for the SU even beginning from ATL 1944 (after a successful 1943 Sealion).

But of course the Channel was a real constraint and overcoming it would have required a substantial resource investment. From that point of view, the analytical question re Sealion is at what point there was no feasible path for Germany to have spare resources to invest in bridging the Channel. That's probably whenever Germany no longer had a chance to beat the SU, which I lean towards locating at some point between July 1940 and November 1941. There are reasonable arguments for a later date...

The hypo of removing the Channel constraint also illustrates a central plank of German strategy had they defeated the SU: recommit to building a credible threat of Sealion, which would tie down enormous Allied forces to protect against the catastrophic contingency of Allied unpreparedness for Sealion. This logic is implicit in Fuehrer Directives #32 and #32a, which discusses reviving Sealion to tie down British forces. The basic logic is one of internal lines: Germany can threaten a broad arc from England to northwest Africa to the MidEast on interior lines; the shipping logistics of defending against these moves simultaneously are impossible. Therefore the bulk of Allied forces would have had to defend against the catastrophic Sealion contingency and largely abandon the MidEast (at least).
History showed that even the Allies had trouble to mount a successful large scale amphibious operation without a series of circumstances, including air superiority, naval cover and most importantly, combined arms practice and planning. The only comparable amphibious operations the Axis mounted - Weserübung and Merkur - were badly planned and bordered a catastrophe. Sadly, the most interesting, and largest scale amphibious endavour the Axis has planned, Operation Herkules, never took place. Also, the heavy air transport planes and units were all but dispersed and neglected before 1943.

But, as more and more I read about the preliminary preparations for Herkules, I think the Axis got better and better in the training and the preparing in these regards. The Fallschirmjäger (and the Paracadutisti) of 1942/1943 were not like their predecessors who fought in 1940/1941.

We will never know what would have happened if there were a few Axis attempts to capture the British positions in Malta and Cyprus, thus, building up invaluable experience and C&C in this type of warfare. Had there been no war in the SU - as a preliminary condition for these operations to be considered at all -, probably the Axis could have fielded the best amphibious force in the world by the second half of 1942 or the first half of 1943.

Where you got it wrong, I think, is that after taking Britain, Germany had to fight a war in the East at all. Stalin and the Wallies were not natural born allies. If Britain would be knocked out of the war by a direct approach, Stalin would most likely appease the Germans as he did after the stunning victories in 1940/1941. If there was no British naval blockade - and for a fact, there wouldn't be one, because Allied-British colonial rule in Africa and the ME would collapse if Britain should fall, thus, there would be little to no need for the Soviets and their raw materials anymore.
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Re: when was it too late for sealion if they got ashore

#8

Post by PunctuationHorror » 17 Oct 2021, 22:33

When France got her beating in May 1940, the British began preparations to counter a german invasion. Establishing Home Guard, building fortifications, ...

I stumbled upon this some times ago and went a bit down the rabbit hole. Until then, I never realized the extent of these fortified defensive lines. Maybe it helps to get a picture:
https://en.wikipedia.org/wiki/British_a ... _World_War
https://en.wikipedia.org/wiki/British_h ... rld_War_II


These preparations were completed by ~ mid '42. So an invasion date as close as possible to May 1940 would probably be ideal since the chances would be highest to find the preparations in an incomplete state.

For psychological matters, the probably best time would be shortly after Dunkirk or shortly after the french surrender. I am not sure if the british government and people would be as fierce in fighting back as the Soviets. Denmark, Norway, Netherlands, Belgium, France quickly surrendered to avoid further bloodshed, while the gov of totalitarian soviet union was not much shaken by the german ways of psychological, aggressive (shock-)warfare. If the French adapted a more soviet-style - or let's say Verdun-ish -sort of resistance, i.e. were showing a higher disregard for human life/were willing to slaughter more people, they could have made "case red" an very unpleasant thing.

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Re: when was it too late for sealion if they got ashore

#9

Post by Peter89 » 18 Oct 2021, 09:06

PunctuationHorror wrote:
17 Oct 2021, 22:33
When France got her beating in May 1940, the British began preparations to counter a german invasion. Establishing Home Guard, building fortifications, ...

I stumbled upon this some times ago and went a bit down the rabbit hole. Until then, I never realized the extent of these fortified defensive lines. Maybe it helps to get a picture:
https://en.wikipedia.org/wiki/British_a ... _World_War
https://en.wikipedia.org/wiki/British_h ... rld_War_II


These preparations were completed by ~ mid '42. So an invasion date as close as possible to May 1940 would probably be ideal since the chances would be highest to find the preparations in an incomplete state.

For psychological matters, the probably best time would be shortly after Dunkirk or shortly after the french surrender. I am not sure if the british government and people would be as fierce in fighting back as the Soviets. Denmark, Norway, Netherlands, Belgium, France quickly surrendered to avoid further bloodshed, while the gov of totalitarian soviet union was not much shaken by the german ways of psychological, aggressive (shock-)warfare. If the French adapted a more soviet-style - or let's say Verdun-ish -sort of resistance, i.e. were showing a higher disregard for human life/were willing to slaughter more people, they could have made "case red" an very unpleasant thing.
In 1940 the Germans had exactly 0 chance to mount an invasion on Britain. There were no SFs or MFPs, no heavy gliders or transports in meaningful quantities, and the KM was in shambles - and the RN was still largely intact. Besides, the Luftwaffe just lost its edge and the preparations for an air and naval offensive were nowhere to be found. In September 1940 the air landing and parachute troops were decimated and in disarray, but the bigger problem was that their doctrine was not upgraded at all.

On top of this, neither the Germans nor the Italians had any troops which had relevant experience in deploying marines and coordinating such assault. The performance on Crete, almost a year later, suggests that any such endavour in 1940 could only end in disaster.

Back to the fortifications: yes, the British Isles were much more prepared in 1942/1943 than in 1940. However, I never said that the Germans / Italians stood a chance; I said that they were the best prepared in this time period, with the Eastern front in their back. And TMP is also right: the British could not defend the perimeter from Iran to Dakar against the full might of the Axis that hasn't attacked the SU.
"Everything remained theory and hypothesis. On paper, in his plans, in his head, he juggled with Geschwaders and Divisions, while in reality there were really only makeshift squadrons at his disposal."

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Re: when was it too late for sealion if they got ashore

#10

Post by Gooner1 » 18 Oct 2021, 12:18

nota wrote:
09 Aug 2021, 23:02
when did the brits ability to defend become to much for an invasion to succeed

lets drop the they can't because of air or sea power will not let them land

and just discuss the time frame for an invasion to have a chance IF by hook or crook
they were able to put boots on the ground in the numbers needed with supply

a few weeks after Dunkirk the axis may have been able to get a sure victory
if they could move troops on shore
was that still possible by fall 1940 or even spring of 1941 ?
Realistically sometime in the summer of 1940 the defences had probably become too strong.

By the Spring of 1941 the disposition of Home Forces was https://www.ibiblio.org/hyperwar/UN/UK/ ... fUK-37.jpg

Image

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Re: when was it too late for sealion if they got ashore

#11

Post by Peter89 » 18 Oct 2021, 12:39

Gooner1 wrote:
18 Oct 2021, 12:18
nota wrote:
09 Aug 2021, 23:02
when did the brits ability to defend become to much for an invasion to succeed

lets drop the they can't because of air or sea power will not let them land

and just discuss the time frame for an invasion to have a chance IF by hook or crook
they were able to put boots on the ground in the numbers needed with supply

a few weeks after Dunkirk the axis may have been able to get a sure victory
if they could move troops on shore
was that still possible by fall 1940 or even spring of 1941 ?
Realistically sometime in the summer of 1940 the defences had probably become too strong.

By the Spring of 1941 the disposition of Home Forces was https://www.ibiblio.org/hyperwar/UN/UK/ ... fUK-37.jpg

Image
Yes, and the RAF got too strong in 1939, and the RN got too strong in 1919.

Germany & Italy were nowhere near organized and experienced enough to invade anything bigger than a small island in the Med. The weakness of the KM was apparent, the anti-shipping LW units were in their infancy. Just a quick reminder; they had to count torpedoes because they didn't have too many of them. We are talking about a few dozen planes only, including converted passenger aircrafts. I see little chance to invade the British Isles by Germany alone. Jodl was quite right in his famous memo. In order to bring the battle to Britain, the Germans had to persuade Franco to give way to Gibraltar, and persude Italy to join fleets and defeat the British in detail as TMP suggested. If the three naval powers (Germany, Italy and Vichy France) joined their fleets, the British would be in an untenable position, that's why they attacked the French fleet at Mers El Kébir. But even if the German and Italian fleets could be joined, the British would have a hard time to maintain their positions in the MTO and around the world, as well as guarding the British Isles against a possible invasion.
"Everything remained theory and hypothesis. On paper, in his plans, in his head, he juggled with Geschwaders and Divisions, while in reality there were really only makeshift squadrons at his disposal."

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Re: when was it too late for sealion if they got ashore

#12

Post by TheMarcksPlan » 19 Oct 2021, 08:54

Peter89 wrote:If Britain would be knocked out of the war by a direct approach, Stalin would most likely appease the Germans as he did after the stunning victories in 1940/1941.
The only appeasement Stalin could offer in this case would be to exterminate Communists/Jews himself, resettle much/most of the Soviet people in Asia, and then commit suicide.
Last edited by TheMarcksPlan on 19 Oct 2021, 08:58, edited 1 time in total.
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Re: when was it too late for sealion if they got ashore

#13

Post by TheMarcksPlan » 19 Oct 2021, 08:57

PunctuationHorror wrote:These preparations were completed by ~ mid '42.
Source?
PunctuationHorror wrote:So an invasion date as close as possible to May 1940 would probably be ideal since the chances would be highest to find the preparations in an incomplete state.
These are lines of field fortifications basically, nothing comparable to a real showstopper like Maginot. All fortification are force multipliers but against even 60 German divisions these wouldn't have been sufficient to allow a small British army - buttressed by poorly-trained Home Guards and territorials - to prevail.
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Re: when was it too late for sealion if they got ashore

#14

Post by Peter89 » 19 Oct 2021, 11:40

TheMarcksPlan wrote:
19 Oct 2021, 08:54
Peter89 wrote:If Britain would be knocked out of the war by a direct approach, Stalin would most likely appease the Germans as he did after the stunning victories in 1940/1941.
The only appeasement Stalin could offer in this case would be to exterminate Communists/Jews himself, resettle much/most of the Soviet people in Asia, and then commit suicide.
I'm not sure, the Soviet Union was still very strong, and by 1942 / 1943 they would complete their preparations for war as well.

Also it is hard to see how events would unfold a few years away from deployable nuclear weapons. It is entirely possible that open confrontation would be avoided (as in OTL) because of the mutual deterrence. (Germany / SU / USA / Japan). In fact, that's what kept peace for most of the time.
"Everything remained theory and hypothesis. On paper, in his plans, in his head, he juggled with Geschwaders and Divisions, while in reality there were really only makeshift squadrons at his disposal."

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Re: when was it too late for sealion if they got ashore

#15

Post by PunctuationHorror » 19 Oct 2021, 17:41

TheMarcksPlan wrote:
19 Oct 2021, 08:57
PunctuationHorror wrote:These preparations were completed by ~ mid '42.
Source?
It's my conclusion of the linked pages. It seems, they started a fortification frenzy in summer 1940 (maybe to keep people occupied with s.th. to do), went on with it during '41 and lost interest in '42, when most was in place or it became apparent that more preparations would become pointless. According to the links, they built ~ 28 000 pillboxes. Accompanied by obstacles, ditches and other things. Compare that to german Sigfired Line/Westwall, Eastwall, soviet Stalin Line, greek Metaxas Line, czech border fortifications, finnish Mannerheim Line and other fortifications of that time.
TheMarcksPlan wrote:
19 Oct 2021, 08:57
PunctuationHorror wrote:So an invasion date as close as possible to May 1940 would probably be ideal since the chances would be highest to find the preparations in an incomplete state.
These are lines of field fortifications basically, nothing comparable to a real showstopper like Maginot. All fortification are force multipliers but against even 60 German divisions these wouldn't have been sufficient to allow a small British army - buttressed by poorly-trained Home Guards and territorials - to prevail.
I have no idea if they would prevail, as too many variables are open. Yes, these fortifications are not the Maginot Line. However, these fortifications lines and "islands" would still help because they consume time and inflict losses. Even if all available german tank and mot divisions get beamed over (or whatever sort of magical transport one might imagine), they would find themselves soon in urban or suburban areas. Bad landscape for armoured warfare. Consumes much infantry. Depending on where you look, UK has plenty hedges, villages, bogs, marshes and other sort of watery places. Also bad tank territory. Fighting in these areas would resemble bocage in Normandy.

IF they put up stiff resistance and IF they started guerilla tactics as planned and IF they were ruthless enough to accept heavy destructions and losses, they could bring the invaders to a point, where the magic transport capacities for replacements and supplies wont suffice anymore. However, this would require a fanatism in the population that I wouldn't set my bets on in 1940. But I have no idea, really.

--------------------------

What could the Germans do? Invade in Scotland, capture (a) port(s) and unload the panzers. Establish Hadrian's Wall 2.0 to bring in more strengths and then rush south.
Or what about a paratrooper raid to capture King and High Commands? German Fallschirm in London. Try to counter this, Bobbies. As someone above said: Pervitine. Much Pervitine. Maybe they can plan to loot some pharmacists for Benzedrine supplly.

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