Could Operation Sealion really have succeeded?

I agree, brilliant post, that would have been the solution.
On the other side of the channel there was nearly...nothing! Some home guards with forks. The British Army didn't have anti-tank capabilities. They simply didn't. With a few hundreds of even smaller tanks (Pz 38 (t), Pz II) and a small number of highly professional paratroopers and infantry, the Wehrmacht could have achieved much.

But: This would have been "ungerman".

 

The problem with using the FJ in May-July 1940 was...

The HUGE loss of transport aircraft that had to be made up; the lack of gliders; a shortage of parachute silk! The Germans ransacked France's seroculture in the summer of 1940 in an attempt to provide enough parachute silk; the number of trained FJ dispatchers killed or injured in May 1940...

Add to that minor issues such as the FJ of 1940 being NOTHING like the FJ of 1941; no heavy weapons' sections, etc. A/T sections depended n being airlanded, not paradropped. And certainly no armour of ANY kind.

THAT would have to come ashore from the sea.

It's also a bit inaccurate to say the British Army had no anti tank capability; they HAD left a lot of 2 pdrs in France....but also brought back quite a few French 25mm Hotchkiss A/T guns. Also, most people forget that any RA field piece could fire solid shot for A/T....the 25-pdr and 18/25-pdr firing solid shot was an effective tank killer! We still had plenty of Boys A/T rifles - which WERE effective against German light armour in 1940.

 

The Italian Air Force had some aircrafts available.

 

It could only have worked IF

1) The Luftwaffe won the air battle
2) It exploited that victory by hitting the RN hard enough to keep it out of the Channel.

As we know, neither of these things happened.

So...could Sea Lion have really worked? No. Too many "ifs."

 

I'm also skeptical about Sealion, but to have any chance they would have to have decided to start preparations earlier as phylo said, perhaps at the May 21 conference when they had reached the Channel and might be in a position, geographically at least, to launch an invasion. At that point they could have determined to make an all-out effort to cut off the BEF from evacuation, a critical blow to Britain in both material and morale terms.

 

Agree with Carronade, While highly improbable not impossible and the one time they would have had the greatest chance would have been from the get go, May not be a pretty and detailed plan but neither was the crossings the Allies maid across the Rhine towards the end of the war.

As to it ending the war, Well not a chance in hell that would occur, While the other allies at the time (largely commonwealth nations) lacked much ability to build large vessels they could build and supply what would be needed to stay in the war, At least long enough for the US to jump in. Not to mention Russia where Germany lost the bulk of her forces (Ground).

 

They would also have had to NOT carry out Fall Rot, but instead plan to attempt a "raid"-type invasion from Occupied France north of the Seine that early Don't forget the two and a half weeks of high-intensity operations that continued on AFTER Dunkirk....

Which I can't see Hitler trying - an invasion of the UK while the French were still fighting, however badly.

Triton - we really can discount the Italians... http//:surfcity.kund.dalset.se/falco_bob.htm

 

In Crete, there was no control of the sea at all.

That is the "safe" approach. Or the german way.
What was necessary in summer 1940 was a port, captured by paratroopers, a relative small number of highly skilled soldiers and, as mentioned, all type of ships and all type of aircraft to supply the invasion forces. The RAF had to attack the ships and invasion forces, no big advantage from radar or range problems for the Bf 109.

The losses for the germans would have been very high, but neglectable in the long term.

 

Actually.....it wasn't the RAF's job necessarily to attack invasion shipping - for as of 1940, Coastal Command had a selection of ENTIRELY unsuitable aircraft for the job, the "best" they had were Blenheim fighters with the ventral 4x.303 gunpack, a total of six squadrons of them...and the couple of Beaufort squadrons. Very few other RAF squadrons had the experience or training for attacking shipping at sea

It would mainly have been the Fleet Air Arm's job. The RAF was to be busy bombing the ports the invasion fleet had left from, to obstruct the Second Wave....and to attack the landing beaches, the various debouchements from them etc.

Paratroopers don't capture ports...except by marching into them on foot Paratroopers actually don't drop in urban areas at all if they can help it - houses hurt. That's why there was never, in ANY version of the Sealion plan, any intention for the FJ to attempt taking a port. At best they were to be classic "blocking forces". Folkestone, and Dover if possible, were instead to be captured by a fast overland dash THROUGH the FJ's blocking positions by troops of the 17th and 35 IDs on the afternoon of S-Day....if they could get off the beaches at Hythe and Dymchurch, get formated, and get across the Royal Military Canal...AND get through the rear of the British forces in the coastal defences at Folkestone and Sandgate

What the Germans needed to do...whenever they were to do it....wasn't to land a small number of highly trained soldiers....it was to land a large enough force that it could take on and defeat any British forces in the immediate area, and thus establish itself firmly ashore.

Suprisingly enough, the British Army was highly trained too, in the main - look at the highly disciplined units that held the British sections of the Dunkirk perimeter....THEN retired in good order. We just hear more about the "digging" divisions and the "unfinished" divisions that were so useless in France...because they were useless - but they were not typical of the British Army.

 

Germany never had sufficient naval power to make Sealion work. I have serious doubts if at even an early date they could have pulled off a landing in sufficient force to establish a solid beachhead. Germany had neither the doctrine, expertise, specialized equipment or units trained in the most complicated of military operations. If they had managed to get troops securely ashore, they would not have been able to sustain them for any appreciable length of time and in the end they would have ended up like all the bypassed Japanese garrisons in the Pacific. You can say what you want about the Brits, but they are stubborn and have big brass cajones. They would have gone after Germany's sealift until every ship in the Royal Navy was at the bottom of the Channel and then strapped 2 pounders on fishing boats and gone at the Germans until all the fishing boats or the Germans were gone.

 

The awkward thing is that the place where they WERE most likely to achieve a decent bridgehead...Romney Marsh....they were further hindered by the Royal Military Canal - which is exactly why it was dug in the 19th century Their immediate plans hinged on a VERY early seizure of a crossing or two intact...while the British planned to blow up all the crossings ASAP....

The awkward thing about this for the British is, of course, how the Germans had successfully mounted major contested river crossings in May 1940!...on rivers every bit as broad and as deep as the RMC - and against far heavier defence than the British were going to mount there.

 

phylo mentioned that the RAF lacked aircraft and more importantly pilot's trained towards bombing ships, What about Germany? Just wondering because many point out the RN as being a decisive factor in SL not being able to work so does that mean Germany lacked the aircraft and pilot's suitable/needed or have people not taken that into account?

Could be a very costly affair for the RN operating in the channel.

 

In Crete, the Luftwaffe was superior. But the main problem of the RN there was ammunition, very unlikely this would have happened in a battle in the Channel. The Luftwaffe didn't have torpedo-bombers but Stukas, Ju 88 and even Me 109 scored hits in the battle of Crete.

As mentioned, mines could give the invasion forces a level of protection and in early 1942, the Wehrmacht was able to supply almost 100000 men in the harsh conditions of a Winter in Northern Russia by air.

 

But how are they going to get even a few tanks over in that time frame much less a "few hundreds". Even the latter Sealion plans didn't call for that many at least in the first few days.

They could have started preperations earlier but they simply don't have enough information at least until the armistace is signed with France to have much of a plan that uses the channel ports. Then there's the time required to get the transports to them. I guess they could have launched an invasion from German ports but that looks like an invitation to disaster to me as it would have been in the face of the RN's greatest strength. I simply can't imagine how they could have got a plan together and the pieces in place to launch even in early July.

As for cutting off the BEF they might have been able to prevent some of the forces that evacuated from Dunkirk from escaping but I doubt they could have kept all of them from doing so and there were other parts of the BEF that were not cut off and Dunkirk. Furthermore a concerted effort to destroy the Dukirk pocket would almost assuredly have given the French more time to rally thus delaying or perhaps even preventing the armistace. Then there's the chance that the attempt fails with all sorts of negative ramifications.

Crete was an entirely different situation. The British forces there were pretty much isolated as well as disorganized and lacking equipment. As it was that op almost failed and took excessive losses even succeeding. Losses that were sufficient to have long term impacts on German operations which rather brings to question the "neglectable" description.

On the other hand they would have to get those bridging assets across the channel and to the RMC. If they reach the RMC too long before the bridging assets get there then the defences along the canal may be beefed up by the time they do get there as well.

 

Well....that's why there were engineering and bridging trains in the First Wave aboard the transports They also planned if necessary to re-use the amphibious PzIIs in an assault on parts of the RMC as soon as possible on S-Day...remembering that they only had to travel a whopping two miles from where they landed to the RMC - without too much between the beaches and the RMC to stop them!

And that's IF their first two options failed to secure crossings there was to be a small FJ "combat engineer" drop on the crossings just behind the Dymchurch Redoubt at dawn in a "coup de main" attempt to take crossings, just like at the Albert bridges in May and the Corinth bridges a year later. This one stood a good chance of nipping up a major crossing before it could be demolished.

Then there would be a second attempt-in-passing later in the morning, as the FJ battalion dropped north of RAF Lympne surrounded the airfield in preparation for a simultaneous attack on the airfield by themselves and from airlanded FJ inside the perimeter; as part of that initial surrounding, the FJ would have come mightly close to the north side of the RMC below the escarpment that Lympne sat on top of!

The secret to taking a river crossing with minimal casualties being of course to take both ends at once

The Canal itself wasn't well defended; it turns out that the pillboxes all along its length weren't occupied after the middle of the summer, they were too damn' obvious and open to air attack! Several still bear evidence of sporadic air attack...instead, the infantry units doled out along its length dug rifle pits, established concealed firing positions etc. in the terrain and any farm buildings back from the Canal. It's possible that the actual "line" of the Canal with its firing parapet and pillboxes was being left for the troops actually ON the Marsh to withdraw back to...but it's not said anywhere.

In modern terms, though...the most useful thing about the RMC was that it was backed for two thirds of its length by a rocky escarpment to the east, and an outcropping of the South Downs to the west! There were only a handful of useable roads for armour and MT through this terrain for the Germans should they cross the RMC...and given the orders for 8RTR over the summer, some elements of which survived into its role as part of MILFORCE under New Zealand' command in September...they'd have met British armour and MT coming the other way on said roads! Them being the only viable routes for the DEFENDERS to move towards the coast there!


Regarding how and from where to launch a smaller, earlier invasion...don't forget they could use Holland's, and Belgium's later, ports from May on As it was, about 2/3s of the final "historical" Sealion plan envisaged using ports further north than French ones!

And if they contemplated instead a divisional-sized "raid"...as the British feared through 1939 and the first months of 1940....THAT could certainly have been mounted from North German ports, seized a port or ports in East Anglia, and dashed to London. The secret of such a raid is to be highly mobile once ashore I.E. MT-heavy, able to travel faster than any mobile counter-invasion forces....remember, we were seriously short of MT for months!...and avoid any large-scale encounters UNTIL they reach their objective.

 

It's not a case, at least on my part, for remembering. I simply didn't know it was that close.

That suggest that such roads and their crossing of the RMC would constitute choke points for the Germans or indeed the British if they operated far on the other side of it. Probably more of a constraint for the Germans as there wouldn't have been that much on "their" side of it.

But it would have risked being intercepted by RN heavy units as well as the light units available. It would be interesting to compare plans for such to Dieppe.

 

If they launch from Germany the barges are simply not going to work. As it was for the channel crossing I've heard estimates that run from 12 to 36 hours depending on where they crossed and just what speed could be obtained. Since they were planing on convoying speed would likely be held to that of the slowest (some of the estimates I've seen suggest the barges could move at up to 6 knots but I doubt the barge trains would achieve anywhere near that speed in practice) and winds could have considerable impact as well as far as crossing time is concerned.

 

In that area they are indeed mega chokepoints....but its the Germans who have the best options then, in respect of bridging it For the British - they can't physically get into Romney Marsh to tackle the German bridgehead there if the crossings are down.

It would only have been intercepted by Home Fleet IF it was spotted...and spotted before entering the southern part of the North Sea. Forbes refused to Bring Home Fleet further south than Great Yarmouth, and nowhere near the Channel. No depth, no sea room, and under the range of the German coastal guns along the Channel coast from midsummer.

Problem is....the RN couldn't and refused to guarantee spotting the invasion fleet...and the burden of recce was on the RAF...who flew morning and evening photo recce over the ports where invasion shipping started to muster in September. In reality, they were only going to know an invasion was on hands once they spotted suddenly empty harbour basins of a morning...

As for light units...there's a problem; after one of the anti-invasion destryer flotillas had to be withdrawn from Dover to Plymouth - this meant TWO of the three were in the western half of the Channel Which left only the Medway flotilla for interception in the Eastern half of the Channel...

Most of the barges were actually to travel empty...and be used to transship men and materiel from the transport ships once they moored up offshore Also - after conversion, the barge types turned out to be MORE seaworthy than the Germans both specified...and expected! They specified that they had to be able to cope with open water and sea state 2...but it turned out that with all the extra ballasting in the form of the steel-reinforced bilges filled with concrete, the extra frame bracing etc., they could actually handle winds of force 4 to 5...and on one exercise with the 17th ID their barges handled wind in excess of force 6 to 8!

As for launching "from Germany" - for a fast, early invasion or "big raid", Germany has quite a few North Sea-facing harbours "From Germany" doesn't have to mean inside the Baltic...