As promised in another thread, here is the proposed outcome of operation sealion according to an exercise by the staff college at Royal Military Academy Sandhurst in 1974.


Introduction

The full text is in 'Sealion' by Richard Cox. The scenario is based on the known plans of each side, plus previously unpublished Admiralty weather records for September 1940. Each side (played by British and German officers respectively) was based in a command room, and the actual moves plotted on a scale model of SE England constructed at the School of Infantry. The panel of umpires included Adolf Galland, Admiral Friedrich Ruge, Air Chief Marshal Sir Christopher Foxley-Norris, Rear Admiral Edward Gueritz, General Heinz Trettner and Major General Glyn Gilbert.

The main problems the Germans face are:

-the Luftwaffe has not yet won air supremacy
-the possible invasion dates are constrained by the weather and tides (for a high water attack)
-it has taken until late September to assemble the necessary shipping

22nd September 1940, morning

The first wave of a planned 330,000 men hit the beaches at dawn. Elements of 9 divisions landed between Folkestone and Rottingdean (near Brighton). In addition 7th FJ Division landed at Lympne to take the airfield.

The invasion fleet suffered minor losses from MTBs during the night crossing, but the RN had already lost one CA and three DDs sunk, with one CA and two DDs damaged, whilst sinking three German DDs. Within hours of the landings which overwhelmed the beach defenders, reserve formations were despatched to Kent. Although there were 25 divisions in the UK, only 17 were fully equipped, and only three were based in Kent, however the defence plan relied on the use of mobile reserves and armoured and mechanised brigades were committed as soon as the main landings were identified.

Meanwhile the air battle raged, the Luftwaffe flew 1200 fighter and 800 bomber sorties before 1200 hrs. The RAF even threw in training planes hastily armed with bombs, but the Luftwaffe were already having problems with their short ranged Me 109s despite cramming as many as possible into the Pas de Calais.

22nd - 23rd

The Germans had still not captured a major port, although they started driving for Folkestone. Shipping unloading on the beaches suffered heavy losses from RAF bombing raids and then further losses at their ports in France.

The U-Boats, Luftwaffe and few surface ships had lost contact with the RN, but then a cruiser squadron with supporting DDs entered the Channel narrows and had to run the gauntlet of long range coastal guns, E-Boats and 50 Stukas. Two CAs were sunk and one damaged. However a diversionary German naval sortie from Norway was completely destroyed and other sorties by MTBS and DDs inflicted losses on the shipping milling about in the Channel. German shipping losses on the first day amounted to over 25% of their invasion fleet, especially the barges, which proved desperately unseaworthy.

23rd, dawn - 1400 hrs

The RAF had lost 237 planes out 1048 (167 fighters and 70 bombers), and the navy had suffered enough losses such that it was keeping its BBs and CVs back, but large forces of DDs and CAs were massing. Air recon showed a German buildup in Cherbourg and forces were diverted to the South West.

The German Navy were despondant about their losses, especially as the loss of barges was seriously dislocating domestic industry. The Army and Airforce commanders were jubilant however, and preparations for the transfer of the next echelon continued along with the air transport of 22nd Division, despite Luftwaffe losses of 165 fighters and 168 bombers. Out of only 732 fighters and 724 bombers these were heavy losses. Both sides overestimated losses inflicted by 50%.

The 22nd Division airlanded successfully at Lympne, although long range artillery fire directed by a stay-behind commando group interdicted the runways. The first British counterattacks by 42nd Division supported by an armoured brigade halted the German 34th Division in its drive on Hastings. 7th Panzer Division was having difficulty with extensive anti-tank obstacles and assault teams armed with sticky bombs etc. Meanwhile an Australian Division had retaken Newhaven (the only German port), however the New Zealand Division arrived at Folkestone only to be attacked in the rear by 22nd Airlanding Division. The division fell back on Dover having lost 35% casualties.

23rd 1400 - 1900 hrs

Throughout the day the Luftwaffe put up a maximum effort, with 1500 fighter and 460 bomber sorties, but the RAF persisted in attacks on shipping and airfields. Much of this effort was directed for ground support and air resupply, despite Adm Raeders request for more aircover over the Channel. The Home Fleet had pulled out of air range however, leaving the fight in the hands of 57 DDs and 17 CAs plus MTBs. The Germans could put very little surface strength against this. Waves of DDs and CAs entered the Channel, and although two were sunk by U-Boats, they sank one U-Boat in return and did not stop. The German flotilla at Le Havre put to sea (3 DD, 14 E-Boats) and at dusk intercepted the British, but were wiped out, losing all their DDs and 7 E-Boats.

The Germans now had 10 divisions ashore, but in many cases these were incomplete and waiting for their second echelon to arrive that night. The weather was unsuitable for the barges however, and the decision to sail was referred up the chain of command.

23rd, 1900hrs - 24th, dawn

The Fuhrer Conference held at 1800 broke out into bitter inter-service rivalry - the Army wanted their second echelon sent, and the navy protesting that the weather was unsuitable, and the latest naval defeat rendered the Channel indefensible without air support. Goring countered this by saying it could only be done by stopping the terror bombing of London, which in turn Hitler vetoed. The fleet was ordered to stand by.

The RAF meanwhile had lost 97 more fighters leaving only 440. The airfields of 11 Group were cratered ruins, and once more the threat of collapse, which had receded in early September, was looming. The Luftwaffe had lost another 71 fighters and 142 bombers. Again both sides overestimated losses inflicted, even after allowing for inflated figures.

On the ground the Germans made good progress towards Dover and towards Canterbury, however they suffered reverses around Newhaven when the 45th Division and Australians attacked. At 2150 Hitler decided to launch the second wave, but only the short crossing from Calais and Dunkirk. By the time the order reached the ports, the second wave could not possibly arrive before dawn. The 6th and 8th divisions at Newhaven, supplied from Le Havre, would not be reinforced at all.

24th, dawn - 28th

The German fleet set sail, the weather calmed, and U-Boats, E-Boats and fighters covered them. However at daylight 5th destroyer flotilla found the barges still 10 miles off the coast and tore them to shreds. The Luftwaffe in turn committed all its remaining bombers, and the RAF responded with 19 squadrons of fighters. The Germans disabled two CAs and four DDs, but 65% of the barges were sunk. The faster steamers broke away and headed for Folkestone, but the port had been so badly damaged that they could only unload two at a time.

The failure on the crossing meant that the German situation became desperate. The divisions had sufficient ammunition for 2 to 7 days more fighting, but without extra men and equipment could not extend the bridgehead. Hitler ordered the deployment of reserve units to Poland and the Germans began preparations for an evacuation as further British attacks hemmed them in tighter. Fast steamers and car ferries were assembled for evacuation via Rye and Folkestone. Of 90,000 troops who landed on 22nd september, only 15,400 returned to France, the rest were killed or captured.



Although it is impossible to say how accurate this view of possible events is, i personally think it is close to how things would have panned out.

The Germans were a continental army, with no experience in amphibious operations.

Even if they had managed to gain a foothold, Churchill had already authorised use of chemical warfare agents against the invaders.

Even if the landings were succesfull the Germans would have found it immensly difficult to progress out of southern England. It would be fairly obvious that their main objective in the campaign would be London, but London is a very large city, with miles of tunnels, caves and a large river running west to east through its centre. It would have been another Stalingrad.

Even if the Germans decided to bypass or flank London, it would have proved difficult.

They lacked the heavy bridging equipment required to cross the Thames east of London, and the river is large enough in that area for warships to sail up and attack any attempted crossing.

The topography west of London is also a factor. The cotswold hills would have been very difficult to take, meaning they would have been forced into two channels, one between the cotswolds and london, the other between the cotswolds and dartmoor. This would have made the defenders job much easier, as neither dartmoor or the cotswolds are suitable for tanks etc.

Your thoughts please

Joe

Just a couple of questions first, Joe. I'm assuming that Galland and the other umpires were just that, and took no part in the decision-making. So who played the roles of the army, navy, and air force commanders, generals, etc? Were they serving staff officers in 1974? If so, don't you think that the operation might have been quite different if experienced generals like Guderian had conducted it, and not staff college students with no experience of full out war?

As for the exercise itself, my first observation is that the ground operations have none of the agressive attacking philosophy inherent to the German 'blitzkrieg', and looks exactly like what it is: a staff college exercise.

Good thread though

David, it's hard to be agressive and fast advancing when most of your tanks and artilery are still in France

Piotr

:-) Good one, Piotr! But that's what I mean. I don't see the Wehrmacht undertaking an invasion of the UK unless they had a damn good chance of getting their armour, artillery, and close air support in. I think it's a bit unrealistic to base the exercise on an invasion without a victory in the Battle of Britain.

Thanks for the comments gents,

The text mentions that it was done by British and German officers, but i am unsure if they were currently serving officers, or ones with experience from the war.

I agree it would have been foolish to launch an invasion without wiping out the RAF first, but if Hitler insisted then it would have been launched anyway.

I've said it before, I'll say it again, and I'll probably go to my grave with it engraved on my heart, "I don't say they can't come, I only say they can't come by sea." Sea Lion would not have worked. It was poorly planned and would have been near impossible to execute. The Germans just didn't have the naval forces, most especially real landing craft, in order to pull it off. The Lufftwaffe couldn't stop the Royal Navy from getting the Army off the beaches at Dunkirk, and they wouldn't have been able to stop the RN from tearing the hear out of an invasion fleet. If the Kriegsmarine tried to stop the RN they would have been cut to ribbons. The KM was successful as they were during the war because the British couldn't concentrate to face them. With all the KM in one place, the channel, the RN would be very happy to concentrate and then it would be a massacre.

IF, and this is a huge if, the German army managed to get enough forces over the Britain then they may have been able to defeat the British. It's just that I don't think there was a chance they could ever get those forces there in the first place.

I have mentioned in the past that not much is known about the defensive fortifications network in Britain at the time.

This website provides a map thats plots the location of the defenses, as well as some photographs of the types of bunkers etc.

Defense of Britain homepage

It is also worth mentioning the arms dumps spread throughout the country in order to rapidly arm the civilian population incase of invasion. They were usually sited in woodland outside of towns and villages, and despite containing outdated weapons it would have certainly provided plenty of resistance equipment.

There was one located a mile or so from where i live close to a local colliery.

Having flicked through all the hits for 'Wales' the Defence of Britain database threw up, it looks like a partial record. I can only find one of the seven AA batteries that defended Newport. At least two of them survive, one in the middle of a golf course at the Celtic Manor. And as for missing pillboxes......

Agreed. Which is why they did not invade. I think it's pointless discussing an invasion based on Sea Lion, because obviously the Wehrmacht saw its faults too. Just as we do.

The mistake wasn't failing to invade, but failure to 'deal' with the UK prior to Barbarossa.

But what if we start from a fresh sheet? Put ourselves in the German high command. What would it have taken to successfully invade? The full might of the Wehrmacht in a western Barbarossa.

Funny this thread has come up. I was in a used bookstore the other day and found a book called "Invasion" by Kenneth Macksey.

Its about this very subject and tells this story in a "what if" sort of way and has thre Germans suceeding at operation SeaLion.

Havn't had a chance to get into it yet but it looks like a interesting read.

Notwithstanding the 1974 Sandhurst exercise (I seem to remember reading it when it was current), Sealion could have worked, but it would have required certain circumstances which were not obtained at the time, & certain decisions to be reversed.
Firstly, the BEF should have been destroyed at Dunkirk. This was a serious German failure, as it would have removed the mass of the trained troops opposing them in Sealion. The fixed defences would have been useless without troops to man them. I'm not too impressed by the mention of "arms dumps all over the place". This was at a time when we were unable to uniform or equip the Home Guard properly, so where were all these weapons, obsolete or otherwise?
Secondly, the Luftwaffe would have needed to obtain total air superiority over Southern England. This would be a basic requirement for jnvasion, as indeed it was for the Normandy invasion in 1944. The failure to obtain this was the reason for the postponement & eventual shelving of Sealion. Once again, this was due to faulty tactics by Goering & Hitler. At the time the Luftwaffe turned on London, they were in fact very close to achieving their objective, Fighter Command airfields in the south-east corner were close to collapse, & the constant bombing of Sector Stations was beginning to affect Fighter Command's command & control system & denying them the theoretical advantages of RADAR. I'm also puzzled by the Luftwaffe strengths quoted, surely the Luftwaffe fielded closer to 2500-3000 aircraft for the Battle of Britain?
As far as the Fleet is concerned, yes it would remain much stronger than the Kriegsmarine, but with no aircover, a sortie in strength would surely lead to a British Pearl Harbor? The AA equipment of surface ships generally (whatever the nation) was inadequate in 1940. The effects of airpower were still not appreciated at this time. In 1941, Force Z (Prince of Wales & Repulse) were sunk in minutes by Japanese aircraft.
The biggest problem would be the weather, but as to how many casualties this would cause, I think this would be subjective. Moreover, without RAF interference, the Germans would be able to ferry more troops in by air, as they did on Crete. I would be interested to know just how many tanks there were in the UK in the aftermath of Dunkirk. I'd guess not many.
Overall I'd say that Sealion could have been achievable given the conditions stated. I don't deny that it would have been costly, but the advantages obtained would have been worth it, I'm sure.

I've also seen that book at local used book stores. From what I can remember of looking through it, and from some discussions on other forums, it basically assumed the Germans made it ashore. The problem with that is that it was actually getting to the shore that was the major problem with Sea Lion.