10 reasons why Op. Sealion could not succeed

Status
Not open for further replies.
I know Sealion is considered ASB but I never got around to completely understanding why it was so. If anyone could write under 1000 words and give 10 main reasons (strategic, tactical, technical or otherwise) why the operation would fail under almost all circumstances (including changing location, date, etc) that would be great.
 
I'll give 8 reasons.

1. Not Sealion related but is essential background Germany didn't have a lot of extra capacity in 1937-1940 to change things. They were out of tradeable resources and couldn't get loans. So Germany in 1939 was as good as they could be. Also Germany got lucky that their plan in the invasion of France worked like it did. If they cut the army to boostthe navy France won't work.

2. The German Navy was a fraction of the British navy. What assets they did have (uboats) was not really useful for escorting an amphibious invasion.

3. The Royal Air Force was good enough to defeat the Luftwaffe easily when defending. Britain could focus on fighters. Germany had to essentially spend double or treble to beat Britain because Britain were only building fighters and the fighters were only giving battle when they had to defend something. Germany had to build fighters and bombers (to make the raf fight) and bombers are much more expensive than fighters.

4. Germany didn't have good long range fighters at this stage. This meant they had to fight in southern England. RAF could withdraw to rest and recover at will.

5. At this time hits were assessed as kills, probable and possibles. A British probable kill of a German plane would usually result in the fighter crashlanding in Britain or going in the channel. A German probable kill of a British plane would result in a damaged fighter landing and being repaired or a crash where the pilot was able to promptly return to duty.

6. Eventually Hitler is going to have to go for the Soviets. Either Hitler's anti communism/Slavs or Stalin starts demanding payment for resources he was providing Hitler. Germany doesn't have forever to wear the British down.

7. Sealion isn't getting lucky and landing an army in Britain. Germany could have done that. The problem is doing it again with supplies. Look at HMS Pinafore's wonderful tale over on warships1 boards. Germany lands half an army on barges on day 1. They lose 2/3rds of the second wave in the channel and run out of supplies in a few days.

8. All ports are set up for demolition in order to prevent supplies landing.
 
Last edited:
Short answer.

They didn't have the sealift capability. They didn't have the escort capability. The troops that would have landed would have been covered in vomit and horse shit and would have had to haul their own tanks and equipment off the beaches, then wait ten days for resupply.
 
8. All ports are set up for demolition in order to prevent supplies landing.
Let's elaborate on this for a second.

On average a German division engaged in heavy fighting required some 200-400 tons of supplies per day (some rounding being done) with the need for supplies resting at 1,100 tons in some cases. I'll use 300 for two reasons, first its exactly in the middle of the two averages, and more importantly its what the British analysis used.

Now, according to British planners, per Ian Fleming, the harbor likely attacked during Sealion was Folkestone, which was capable of moving 150 tons of supplies per day with its equipment destroyed (this is a safe assumption given the Allied difficulty capturing an intact port in 1944). Now, with German work this capacity can rise to 600 tons per day. If the port of Dover is captured that adds about 800 tons per day. Let's assume both of these are captured AND that the RN decides lead paint is an awesome drink so they don't interfere. That's 1,400 tons of supplies per day. Sound like a lot? Well, its not. The German plan was for 11 divisions to be landed. Nine infantry, two paratrooper. That means they need an average of 3,300 tons per day. So with both ports taken they will be getting 42% of the supplies necessary to keep fighting.

Without Dover its 18%. If repairs on Folkestone are not completed, its 5%.

So basically, even IF the RN doesn't try to stop them, and even IF the Germans have infinite sealift capacity (they don't) they still can't supply the soldiers they've landed. Now you might say, but what about unloading on the beach. Sure that's possible (assuming infinite sealift capacity), but extremely difficult, and more importantly TIME CONSUMING. The longer the barges need to unload their supplies the longer they have to wait until the NEXT shipment arrives across the Channel.

That's not even getting into another problem, the German army is primarily horse-drawn. Which means all those horses have to brought ACROSS the Channel.

In River Barges...
 
Out of curiosity (I believe you), why weren't the Marines in similarly appalling shape when they landed on Normandy?
Because the Marines didn't land on the beaches of Normandy. That was strictly an Army show. Go watch the first few minutes of Saving Private Ryan. You'll see soldiers in the Higgins boats puking their guts out on the run into the beach.
 
Because the Marines didn't land on the beaches of Normandy. That was strictly an Army show. Go watch the first few minutes of Saving Private Ryan. You'll see soldiers in the Higgins boats puking their guts out on the run into the beach.
Yep, the vast majority of the invading troops at D-Day were seasick.
 
I know Sealion is considered ASB but I never got around to completely understanding why it was so. If anyone could write under 1000 words and give 10 main reasons (strategic, tactical, technical or otherwise) why the operation would fail under almost all circumstances (including changing location, date, etc) that would be great.
1) Britain had a massive lead over the germans in terms of naval superiority.

2) Britian had a higher rate of air plane production than Germany meaning that so long as it had pilots it could retain air superiority.

3) As combat was over the UK British pilots could bail out at any time and get back into the fight after some R&R, so pilot loses were relatively low (where as Germans who bailed out became forced farm labour), combine this the BCATP pumping out pilots like no tomorrow and we get a rate of exchange where the RAF actually grows stronger as the Luftwaffe erodes away.

4) The German invasion of Norway had relied heavily on surprise, that was something that they simply would not have with the UK.

5) IIRC a significant number of the boats the Germans had earmarked for the operation were river barges, and that says just about everything...

6-10) My head's telling me there's more, but I'm sure someone else will get it.
 
Last edited:

Tovarich

Banned
Because the Marines didn't land on the beaches of Normandy. That was strictly an Army show. Go watch the first few minutes of Saving Private Ryan. You'll see soldiers in the Higgins boats puking their guts out on the run into the beach.
Those Higgins boats do at least look seaworthy though, whereas Rhinebarges aren't.

So whilst the Wallies were puking, they could at least stand up after doing so.

Not that I've ever been on anything rougher than the cross-channel ferry (where as long as you sit roughly central & don't consume too much duty-free it's ok).
 
Out of curiosity (I believe you), why weren't the Marines in similarly appalling shape when they landed on Normandy?
The Allies didn't take horses with them (the French may have had some in cans or baguettes), but they were an integral part of the Wehrmacjt's logistical plan.

In addition, the Allies had clear and well thought out plans for getting heavy equipment across shingle beaches and avoiding another Dieppe. The Wehrmacht didn't.
 
Last edited:
Let's elaborate on this for a second.

On average a German division engaged in heavy fighting required some 200-400 tons of supplies per day (some rounding being done) with the need for supplies resting at 1,100 tons in some cases. I'll use 300 for two reasons, first its exactly in the middle of the two averages, and more importantly its what the British analysis used.

Now, according to British planners, per Ian Fleming, the harbor likely attacked during Sealion was Folkestone, which was capable of moving 150 tons of supplies per day with its equipment destroyed (this is a safe assumption given the Allied difficulty capturing an intact port in 1944). Now, with German work this capacity can rise to 600 tons per day. If the port of Dover is captured that adds about 800 tons per day. Let's assume both of these are captured AND that the RN decides lead paint is an awesome drink so they don't interfere. That's 1,400 tons of supplies per day. Sound like a lot? Well, its not. The German plan was for 11 divisions to be landed. Nine infantry, two paratrooper. That means they need an average of 3,300 tons per day. So with both ports taken they will be getting 42% of the supplies necessary to keep fighting.

Without Dover its 18%. If repairs on Folkestone are not completed, its 5%.

So basically, even IF the RN doesn't try to stop them, and even IF the Germans have infinite sealift capacity (they don't) they still can't supply the soldiers they've landed. Now you might say, but what about unloading on the beach. Sure that's possible (assuming infinite sealift capacity), but extremely difficult, and more importantly TIME CONSUMING. The longer the barges need to unload their supplies the longer they have to wait until the NEXT shipment arrives across the Channel.

That's not even getting into another problem, the German army is primarily horse-drawn. Which means all those horses have to brought ACROSS the Channel.

In River Barges...


Germans never based large scale invasion plans on ports, they were all based on landing on beaches, using 1/2 the so called river barges to shuttle supplies ashore from the 150 transport merchant ships employed. But First Sea Lord Pound concluded that the KM could deliver 100-200,000 troops over night in a port to port invasion and RN could not do anything to prevent this. Churchill accepted this conclusion, which is probably why he didn't share your enthusiasm for the operation. Britain was teetering on the edge of collapse and the shock of such an action would bring them to crises.

BTW the demand for supply of 300-600 tons per day per division was estimates based on fighting on the Eastern Front mid war. No way the Wallies are anywhere as tough as that in 1940 after the Dunkirk disaster.

In naval clashes of the period - Nazi warships were twice as effective as Wallies.
 
Germans never based large scale invasion plans on ports, they were all based on landing on beaches, using 1/2 the so called river barges to shuttle supplies ashore from the 150 transport merchant ships employed. But First Sea Lord Pound concluded that the KM could deliver 100-200,000 troops over night in a port to port invasion and RN could not do anything to prevent this. Churchill accepted this conclusion, which is probably why he didn't share your enthusiasm for the operation. Britain was teetering on the edge of collapse and the shock of such an action would bring them to crises.
So? Those troops are useless if they can't be kept supplied. And they can't be.

Meanwhile the kind of invasion that is being proposed took years for a force with a far higher industrial level, with total superiority on sea and in the air, AND with their opponent fighting a larger war to the East to successfully mount.

BTW the demand for supply of 300-600 tons per day per division was estimates based on fighting on the Eastern Front mid war. No way the Wallies are anywhere as tough as that in 1940 after the Dunkirk disaster.
Correct those are what the estimates are based on. Because that's where the data is. 300 tons was the number used by British planners per Fleming. If you can supply a better number please do so with an explanation of what said number is based on.

In naval clashes of the period - Nazi warships were twice as effective as Wallies.
Citation needed.
 
10 is a lot and by the time we get to the end we'll be grasping at straws, but to take some of the main points in order, and bearing in mind that most of these aren't so much "reasons Sea Lion must fail" as "reasons why Sea Lion is unusually challenging as a military operation," which, taken all together, raise the difficulty level well beyond any sense of feasibility:

1.) German planning is premised on the comprehensive defeat of the Royal Air Force BEFORE the invasion can begin. Obviously, that didn't happen. Without air superiority, the Germans themselves think it's a no-go.

2.) The Germans do not have a proper, purpose-built amphibious fleet. This means they have to strip their inland waterways of small cargo craft and hastily refit them to carry troops, horses, and vehicles. This makes the invasion fleet far slower and less seaworthy than anything the Allies ever mount an operation with.

3.) It's unlikely the Germans can get this assemblage to the invasion beaches without being detected. Obviously, regardless of the level of preparation, lack of surprise is always an extra challenge.

4.) The Germans do not have good naval cover for this fleet. A large proportion of what should have been the escorting destroyers were already sunk. At least in terms of destroyer class and up, the Royal Navy will outnumber the Germans quite literally by an order of magnitude.

5.) Even if the first wave gets through that fortunately unscathed, the likelihood of each next resupply and reinforcement waves making it through, given points 2 and 4, rapidly diminishes towards zero. In short there is a very high likelihood that any army units making it ashore will be cut off.

6.) It's unlikely that the Germans can resupply such a beachhead by air, but to the extent they try, it will necessarily draw away resources they would have been using to advance on the ground, fight the RAF, and fight the RN.

7.) In theory the Germans can build up their forces to address these problems after Dunkirk, but they can't do so in a vacuum. The longer they dither, the better prepared the British will be. The temporary disarray after Dunkirk will be repaired by the fall, and it's obviously impossible to do this in winter, and then you're into 1941 already.

8.) In theory the Germans can also build up their forces to address these problems BEFORE Dunkirk, but again, they can't do so in a vacuum. Not only will the British be likely to step up their game in response, but it will draw away resources needed for the invasion of France, and if a sudden obsession with defeating Britain scuppers the invasion of France, all of this is a moot question anyway.

9.) Always going on in the back of the German military mind is that Russia is the easier target anyway. With hindsight this seems absurd, but remember, Germany had already successfully invaded Russia once, in the First World War. Successful invasions of Britain are in contrast not common. This is less of a reason why the invasion would fail then a reason why Germany wouldn't launch it to begin with.

In naval clashes of the period - Nazi warships were twice as effective as Wallies.
Cold comfort when you're outnumbered 10 to 1.
 
Germans never based large scale invasion plans on ports, they were all based on landing on beaches, using 1/2 the so called river barges to shuttle supplies ashore from the 150 transport merchant ships employed. But First Sea Lord Pound concluded that the KM could deliver 100-200,000 troops over night in a port to port invasion and RN could not do anything to prevent this. Churchill accepted this conclusion, which is probably why he didn't share your enthusiasm for the operation. Britain was teetering on the edge of collapse and the shock of such an action would bring them to crises.

BTW the demand for supply of 300-600 tons per day per division was estimates based on fighting on the Eastern Front mid war. No way the Wallies are anywhere as tough as that in 1940 after the Dunkirk disaster.

In naval clashes of the period - Nazi warships were twice as effective as Wallies.
have seen that term "river barges" used repeatedly, to ask a stupid question is that referring to MFP/AFPs or Siebel Ferries or some other actual Rhine barges?

am not endorsing the use of either but the MFPs were used in numerous roles successfully, however that was after a period of development.
 
In naval clashes of the period - Nazi warships were twice as effective as Wallies.
Too bad thanks to Norway, the KM could only field 10 destroyers then when the Brits had the entire home fleet that could be sorted from their bases and outnumber the KM massively so yeah doesn't matter even if the Germans are 2x as good as the RN Norway hello they are swamped as the brits interdict the KM at night and run riot over all those delicious convoys carrying food and munitions while all German efforts are focused on the R class BB in Southampton was it?
 
Calais harbour is visible from Dover, so the British could watch, over a couple of days, the invasion fleet assembling inside Calais, then very slowly putting to sea and forming up outside.
 
have seen that term "river barges" used repeatedly, to ask a stupid question is that referring to MFP/AFPs or Siebel Ferries or some other actual Rhine barges?
Rhine barge (albeit of a more modern design), of type intended to cross Channel in Sealion:



Good luck with that. To be fair, it wouldn't ride quite so low in the water with people rather than cargo, but the Rhine barges are designed for use on the Rhine, rather than on the open sea.

It's one reason why Sealion gets rather short shrift.
 
Rhine barge (albeit of a more modern design), of type intended to cross Channel in Sealion:



Good luck with that. To be fair, it wouldn't ride quite so low in the water with people rather than cargo, but the Rhine barges are designed for use on the Rhine, rather than on the open sea.

It's one reason why Sealion gets rather short shrift.
To be honest, there is an awful lot more to the barges question than just them riding low in the water or being threatened with swamping.

Being designed for the Rhine they are flat bottomed. The Rhine (and you can take my word for this because I lived next to it for five years) is relatively flat and calm, even when it's flooding. The English Channel is notoriously choppy, and what feels smooth on a 7000 ton car ferry is going to be totally different on a flat bottomed barge. Horses are going to have trouble standing up, and some of them will be on board for over 24 hours.

Only a third of the barges had engines, so they had to tow the other two thirds. This is normal on the Rhine. According to http://www.cruisersforum.com/forums/f17/current-on-the-river-rhine-63202.html the normal current is 3 knots and always in the same direction. Easy. The currents in the eastern Channel are not much faster, but are in multiple different directions and would be a nightmare for any formation involving dead weight on the end of tow lines (http://www.visitmyharbour.com/articles/3173/hourly-tidal-streams-english-channel-east). Don't forget, the plan was to sail across in the dark and communicate by loudhailer. Sail across as a block, turn and sail along the coast in a line astern, and then simultaneously turn and head for the beachs of the south coast. Of course, the Germans didn't have enough sailors for one per barge, so they pressganged seamen from other conquered nations. I think it would go something like this.
"Was machen Sie da?!?! Abstand halten!!!"
"Jeg har absolut ingen idé om hvad du siger."
"Minulla ei ole mitään käsitystä siitä, mitä sanot.."
"Je n'ai absolument aucune idée de ce que vous dites."
"Ik heb helemaal geen idee wat je zegt."
"Jeg har absolutt ingen anelse om hva du sier."
"Nie mam pojęcia, co mówisz."

All this is, of course, before we reach the multiple issues of landing, unloading and then refloating the barges to tow back to the continent for reuse. Even by the most optimistic figures, it would have been a week before reinforcements could arrive.

There is, of course, much more fun to be had with the barges, but that will do for now.
 
To be honest, there is an awful lot more to the barges question than just them riding low in the water or being threatened with swamping.
Absolutely, and we haven't even got into the issue of manoeuvrability and unloading over a beach, and how close to the shore are they going to get, and just what will happen when you put a huge bunch of them together en masse at night with inexperienced seamen who don't necessarily speak the same language and with no training in working as a group.

I rather suspect that had Sealion been attempted, the British wouldn't actually need to do anything, the barges wouldn't have made it across.

But the image does show a technical problem with using these vessels in waters noted for having waves. I'm not getting into the issue that the tidal currents in the Channel are typically 7-10 knots, and the barges are typically 3-4 knots.

I rather suspect that the film of Sealion would star Charlie Chaplin.
 
Top
Status
Not open for further replies.
Top