Glossary of Sealion Threads

[Saphroneth]

If the Germans had won the battle of Britain, and pressed their advantage in maintaining air superiority why couldn't they have just bombed the royal navy into oblivion? If ww2 taught us anything it's that air superiority decided the fate of navies. Or even brought up the italian navy to assist with whatever was left of it after the air campaign.

Wouldn't that have cleared the way for sealion?

Okay, here's why.

Dive bombers do not sink battleships.


...what, you wanted more?

Yes, air power was the decisive arm. But the times when air power was able to sink battleships tend to boil down to one of three cases:
The ship was at anchor, not under wartime conditions. (Believe you me, the Royal Navy nearly a year into the war is going to be under serious wartime conditions.)
The ship was hit by a highly advanced weapon from the late war, such as a Fritz.X glide bomb or a Tallboy. These weapons require a very specific attack path, and usually air superiority. And they've not been invented in 1940.
Or, the most usual case, it was LOTS AND LOTS of torpedoes. Torpedoes, not bombs - and the Luftwaffe sucked at anti ship work, and especially sucked with torpedoes. (Look up how much fire Yamato or Prince of Wales absorbed, and observe that they did not have any significant air cover - and it still took THAT to down them.)

Now, the more usual role of naval air power in 1940 was to find, harm, hamper and slow enemy ships. The idea is, if you have to face Bismarck when she can't steer, or she's lost a boiler, or she's just taken on a few thousand tonnes of water into her TDS, while your own ships are undamaged, then you will be able to pound her to bits more easily.

(The Stukas and Ju-88s, by the way, are the dive bombers the Germans have, and they're optimized for air support - not naval air power. The Germans did not do naval air power in any significant way, and they may not have even had much in the way of AP bombs. They are also needed for the landings themselves, because they fulfil the role of artillery for the arty-light tactics the Heer rely on and will need to do if they get ashore.)

So capital ships are, more or less, safe from the LW.

Destroyers, on the other hand, are vulnerable to LW bombs. But they're also much, much harder targets. (Consider the number of bombs dropped on the slowly moving destroyers at Dunkirk. Not many casualties. Hitting a destroyer is hard - and it's not until Crete that the LW seems to have got the hang of hitting moving ships at all.)

Cruisers are the middle ground. They can take a few bombs, but they might get hit by a few. Tricky.

What it boils down to is that the LW will, if it is able to do better than it did OTL, be able to sink... let's go hog wild and completely beyond the realm of plausibility, and say every aircraft carrier, one battleship, two battlecruisers, six cruisers and eighteen destroyers - thus making it the single greatest air power versus naval power victory in WW2 by a fair way.
Great.
Now, since Stukas are short legged, that attack will have taken place at most a couple of hours at flank speed from the invasion itself. (Assuming, that is, that the Royal Navy don't just make sure they reach the invasion area at night, because it's their choice.) In the time it takes the Stukas to land, rearm, get their aircraft serviced, and launch a second, inevitably smaller, strike (Inevitably, because that close to Britain the fleet will have air cover - indeed, if the LW is making a maximum effort strike, then there's nothing else for Brit fighters to do but shoot down Stukas over the Home Fleet), the Royal Navy has had at least an hour or two merrily blowing up invasion barges.

To prevent an attack on Great Britain is the reason the Royal Navy exists. If it looks like the invasion will be a success, they will throw everything that floats into the channel and not leave until they've each used up all their ammunition and then rammed things until their ships have fallen apart.
After all, England Expects.

 

[Ian Hathaway]

Okay, here's why.

Dive bombers do not sink battleships.


...what, you wanted more?

Yes, air power was the decisive arm. But the times when air power was able to sink battleships tend to boil down to one of three cases:
The ship was at anchor, not under wartime conditions. (Believe you me, the Royal Navy nearly a year into the war is going to be under serious wartime conditions.)
The ship was hit by a highly advanced weapon from the late war, such as a Fritz.X glide bomb or a Tallboy. These weapons require a very specific attack path, and usually air superiority. And they've not been invented in 1940.
Or, the most usual case, it was LOTS AND LOTS of torpedoes. Torpedoes, not bombs - and the Luftwaffe sucked at anti ship work, and especially sucked with torpedoes. (Look up how much fire Yamato or Prince of Wales absorbed, and observe that they did not have any significant air cover - and it still took THAT to down them.)

Now, the more usual role of naval air power in 1940 was to find, harm, hamper and slow enemy ships. The idea is, if you have to face Bismarck when she can't steer, or she's lost a boiler, or she's just taken on a few thousand tonnes of water into her TDS, while your own ships are undamaged, then you will be able to pound her to bits more easily.

(The Stukas and Ju-88s, by the way, are the dive bombers the Germans have, and they're optimized for air support - not naval air power. The Germans did not do naval air power in any significant way, and they may not have even had much in the way of AP bombs. They are also needed for the landings themselves, because they fulfil the role of artillery for the arty-light tactics the Heer rely on and will need to do if they get ashore.)

So capital ships are, more or less, safe from the LW.

Destroyers, on the other hand, are vulnerable to LW bombs. But they're also much, much harder targets. (Consider the number of bombs dropped on the slowly moving destroyers at Dunkirk. Not many casualties. Hitting a destroyer is hard - and it's not until Crete that the LW seems to have got the hang of hitting moving ships at all.)

Cruisers are the middle ground. They can take a few bombs, but they might get hit by a few. Tricky.

What it boils down to is that the LW will, if it is able to do better than it did OTL, be able to sink... let's go hog wild and completely beyond the realm of plausibility, and say every aircraft carrier, one battleship, two battlecruisers, six cruisers and eighteen destroyers - thus making it the single greatest air power versus naval power victory in WW2 by a fair way.
Great.
Now, since Stukas are short legged, that attack will have taken place at most a couple of hours at flank speed from the invasion itself. (Assuming, that is, that the Royal Navy don't just make sure they reach the invasion area at night, because it's their choice.) In the time it takes the Stukas to land, rearm, get their aircraft serviced, and launch a second, inevitably smaller, strike (Inevitably, because that close to Britain the fleet will have air cover - indeed, if the LW is making a maximum effort strike, then there's nothing else for Brit fighters to do but shoot down Stukas over the Home Fleet), the Royal Navy has had at least an hour or two merrily blowing up invasion barges.

To prevent an attack on Great Britain is the reason the Royal Navy exists. If it looks like the invasion will be a success, they will throw everything that floats into the channel and not leave until they've each used up all their ammunition and then rammed things until their ships have fallen apart.
After all, England Expects.

I think you slightly missed the point that LestWeForget was making. If everything had gone to plan the Luftwaffe would have had 10 days after achieving air superiority to "soften up" Britain before the invasion date. Targets would have included the naval bases at Rosyth, Immingham, Sheerness, Harwich and Plymouth where the main RN anti-invasion forces were gathered. I'm not going to speculate as to how effective these attacks would have been but I will say that you don't need to sink a ship to put it out of action even if its just for a week or two. Disruption is just as effective as destruction in the short term. The Germans also had plans to keep the RN major units occupied in the North Sea with diversionary invasion fleets being launched from Norway and the ever present threat of a break out into the Atlantic. Again these were just short term measures, enough to delay the appearance of the RN capital ships until a beachhead had been established on the south coast of England. Once it was clear to the Brits that the Germans were just playing games the fleet would have sailed making the 24 hour journey down the east coast of Britain where they would have been in range for the He111 and Ju88 expending the majority of their AA ammunition as they go (being so close to the shore they may have been able to resupply on the move, who knows?). The RN may then have the luck of avoiding the U-Boat patrols set up specifically to intercept them and may be able to negotiate the minefields sewn by the Germans in a way that allows them to minmise the time taken to get through. Only at that point would they face the Ju87, T Boat and E boat attacks from any of the German forces that still survive.

 

[Saphroneth]

The idea of level bombers doing anything useful to a ship fleet is ridiculous. Level bombers just plain do not even HIT ships unless they "shotgun" the enemy fleet, and to do that you need to not be being shot at by flak *and* have no interference from fighters. This kind of reason is why the heavy bombers at Midway dropped hundreds and hundreds of bombs but didn't land a single hit - and that's with heavy bombers from 1942 designed FOR the anti-shipping role.
Again, naval air power just wasn't much cop against battlefleets unless it had torpedoes, or unless the fleet had nothing heavier than a cruiser or aircraft carrier.

As for the minefields - the purpose of a minefield Dover-Calais is obvious. You get either surprise or the minefield, not both... for that matter, given the tiny surface fleet available to the Axis at this point, Home Fleet could simply send sufficient forces to handle the invasion fleet very roughly both to the east coast AND to the south coast.
To have the Luftwaffe achieve anything useful, or to have the subs achieve anything useful, you have to extrapolate from attacks at ships in harbour or ships which are not at action stations, which are not expecting attack, to ships which ARE expecting action and which are ready for war.
I await multiple examples of a capital ship being sunk in combat by a U-boat... the Italians should have had the opportunity, what with the size and aggressiveness of Forces H and Mediterranean.

 

[Ian Hathaway]

The idea of level bombers doing anything useful to a ship fleet is ridiculous. Level bombers just plain do not even HIT ships unless they "shotgun" the enemy fleet, and to do that you need to not be being shot at by flak *and* have no interference from fighters. This kind of reason is why the heavy bombers at Midway dropped hundreds and hundreds of bombs but didn't land a single hit - and that's with heavy bombers from 1942 designed FOR the anti-shipping role.

Again, naval air power just wasn't much cop against battlefleets unless it had torpedoes, or unless the fleet had nothing heavier than a cruiser or aircraft carrier.

As for the minefields - the purpose of a minefield Dover-Calais is obvious. You get either surprise or the minefield, not both... for that matter, given the tiny surface fleet available to the Axis at this point, Home Fleet could simply send sufficient forces to handle the invasion fleet very roughly both to the east coast AND to the south coast.
To have the Luftwaffe achieve anything useful, or to have the subs achieve anything useful, you have to extrapolate from attacks at ships in harbour or ships which are not at action stations, which are not expecting attack, to ships which ARE expecting action and which are ready for war.

I await multiple examples of a capital ship being sunk in combat by a U-boat... the Italians should have had the opportunity, what with the size and aggressiveness of Forces H and Mediterranean.

Sorry if I didn't put my point across clearly ... I was not intending to suggest that the RN capital ships could be sunk, just delayed long enough for the invasion force to secure a bridgehead, an airfield or two and some sort of supply line.

The first thing of note is that, with the exception of an older Battleship at Plymouth, the RN capital ships were at Rosyth. For the fleet to set sail and get out into open waters, a distance of 30 nautical miles, is probably going to take 4-5 if they are already on alert. For the remainder of the journey to get to a position where they can effectively disrupt the landing barges would take a further 18 hours assuming the fleet can maintain a constant speed of 21kn. Therefore even if the fleet sets sail the moment the invasion is detected it will not arrive until after the first waves of motor boats and barges lands.

According to German documents of the time they planned to delay the fleet at Rosyth by putting doubt in the Admiralty's mind by launching diversionary operations on the North East coast of England. Merchant vessels loaded to look like they were carrying troops/supplies/vehicles etc were to set sail from Norway with orders to turn back at the first sign of danger. But by then the seed would already have been sewn that invasion was imminent in the North as well as the South of England. Already it will take a day for the RN fleet to travel ... now add a couple of days to that for the British to realise they are being tricked, maybe more if the Germans set sail with a major surface vessel threatening to break out into the Atlantic.

So we now don't see the capital ships for 3-4 days ...

Now add into that the other delaying tactics, constant air attack (whether it causes damage or not), the threat of U-Boat attack and the minefields and you can probably add another day to those figures. Lets not forget the action by the Luftwaffe back in April 1940 against elements of the Home Fleet which caused minor damage to one Battleship, one Heavy Cruiser, two Light Cruisers and sank a Destroyer when 80 Ju88 and He111 attacked them for 3 or more hours, losing 4 Ju88s in the process but forcing the fleet to retreat for a lack of AA ammunition. Imagine sailing for 22 hours with that kind of threat, how much it would slow the fleet down having to renew their supplies or worse still pick up survivors from any ships that were unfortunate enough to be sunk.

I think my point here is that people seem to assume that the RN capital ships will just magically appear whilst the invasion fleet is still mid-Channel when in fact it is likely to appear a week or so after the invasion if at all.

However all of that is fairly academic as the Germans WILL have a strong destroyer force to deal with from Harwich and Sheerness which does have the ability to disrupt the landings ... then shortly afterwards there will be cruisers arriving from Immingham ... and other ships arriving from Plymouth.

 

[Saphroneth]

The RN knew the weaknesses of the Kriegsmarine, as well - they knew quite well that it didn't have any heavy units. As such, it would be entirely possible to detach a few heavy cruisers to handle the northern attack (which has much more time involved - since it would take so long to get there with the many slow transports available, or if they used the few - very few - fast transports, then they could just sink those. If there's more ships than a couple of cruisers and the Hood could cope with, then they would take so long that heavy units could be diverted from the southern attack.)
The Royal Navy, for all that the doctrine was not always great, weren't morons either - the priority attack is the one towards the south coast, where most of the enemy will be coming from in any event due to the scale of the barge concentration and where the crossing time is much shorter.
And really any amphibious invasion - any at all, save for the invasion of Crete (which was a year or so later and hitting a lightly defended island) CANNOT rely on an air supply line. It is imperative to obtain a port, and do it soon - which is precisely what the RN can stop them doing.

The Kriegsmarine said in their official documents that the best they could do was a narrow landing - a "dash" as it were. The Heer demanded a wide landing, because to do otherwise would (they said) invite a speedy defeat because of it being easy to contain the narrow beach-head.

 

[Saphroneth]

Actually, I think it's worth putting this here, since I just ran across it. This is in regard specifically to the issue of using the Luftwaffe in an anti shipping role, so it's relevant, though it also covers more general aspects of Sealion and hence deserves a position on this thread.

I have only recently come across this site, so please forgive me if I repeat comments already made by others.

The fact is that Sealion was never remotely feasible after the heavy losses sustained by the Kreigsmarine during the Norwegian campaign. The heaviest vessel available to Germany in Summer 1940 was a single heavy cruiser, Hipper, which had defective engines and was unfit for prolonged operations.

To escort Sealion, there were six or seven operational destroyers, with a few torpedo boats and minesweepers. Against these, the RN had some sixty destroyers and cruisers based between Harwich/Sheerness and Plymouth, together with several hundred smaller vessels.

Other destroyers could, in addition, be called back from convoy escort duty within 24 hours. The Admiralty did not intend the Home Fleet to move into the southern part of the North Sea unless heavy German vessels did (obviously, the Admiralty did not know exactly how weak the Germans were, and had to guard against a breakout into the Atlantic), reasoning that the forces already in place were more than adequate to do the business.

German coastal batteries were useless; in the whole of WW2 they failed to sink a single allied ship. Similarly, any minefields the Germans could lay could be swept as quickly by the RN, who had 698 minesweepers in commission by September, 1940. Indeed, given the strong currents in the Channel, there would have been a serious risk of mines breaking free and causing confusion among the barge trains they were meant to protect.

The Luftwaffe in Summer/Autumn 1940 was not, despite the common misbelief, particularly adept at hitting ships at sea. They had failed miserably at Dunkirk, where only 4 of 39 RN destroyers were sunk by air attack, and these were all either stopped or moving slowly in restricted waters. I can quote senior officers from von Richthoven to Dinort who constantly lamented the problems they were encountering, and who pointed out, quite strenuously in some cases, that the Luftwaffe could not stop the RN from breaking into the barge convoys and annihilating them. Certainly, they had improved significantly by May 1941, but May 1941 is not September 1940!

The barges themselves were incapable of making the Channel crossing unaided. The intention was for two barges (one powered and one unpowered), to be towed by a tug/trawler/transport vessel, but there was a serious shortage of such vessels. Eventually, only about 570 were assembled, so most of the 2400 or so barges available would have been surplus to requirements, or simply available to replace losses. There were, however, no spare transports or tugs to replace losses of these.

Transport by air - According to Luftwaffe records, in mid-August, the Luftwaffe had 224 transport aircraft available, nowhere near enough to transport 7 Fliegerdivision to Folkestone, let alone to resupply any landing areas.

The German invasion plan intended that a first wave of nine divisions would land at four separate beaches. It would, however require ELEVEN days for these divisions to land, and they would lack most of their motorised transport and their artillery. The schedule, by the way, assumed that there would be no significant losses from naval action!

Do not be misled by the Sandhurst wargame. I actually knew (or more accurately was tutored at University by) one of the organizers, and he told me that the purpose of the game was to set up a scenario which led to a land battle between German invaders and British defenders. He confirmed that, in order to make this possible, the real historical dispositions of the RN vessels in home waters were altered to allow a window of opportunity for the Germans to cross. Otherwise, he and his colleagues had concluded that no effective German forces would land at all!

Finally, there is the question of resupply. In 1940 a typical German infantry division required some 300 tons a day to keep it in action. In the (unlikely) event that 9 divisions and two airborne divisions got ashore, they would need 3300 tons per day. The two ports that the Germans might hope to capture were Dover and Folkestone, which in full working order could handle 800 and 600 tons per day each. Even if the British had not unsportingly destroyed port facilities or left blockships, this would leave a shortfall of 1900 tons per day. No doubt the horses the Germans would have brought with them would have eaten English grass, but where would the rest have come from? In non-existent JU52s, or in towed barges under constant attack from RN surface forces, landing on open beaches under constant fire from British defenders?

The best recent book on Sealion, for anyone interested in the reality as opposed to the fantasy, is a detailed analysis of the whole subject called 'Hitler's Armada' which makes many of the points I have made, and provides masses of supporting evidence. I recommend that anyone who thinks Sealion could have been anything more that a pipe dream gets hold of a copy in order to learn a few facts.

 

[Ian Hathaway]

The RN knew the weaknesses of the Kriegsmarine, as well - they knew quite well that it didn't have any heavy units. As such, it would be entirely possible to detach a few heavy cruisers to handle the northern attack (which has much more time involved - since it would take so long to get there with the many slow transports available, or if they used the few - very few - fast transports, then they could just sink those. If there's more ships than a couple of cruisers and the Hood could cope with, then they would take so long that heavy units could be diverted from the southern attack.)

During World War II, Operation Herbstreise (Autumn Journey in German) was a planned series of deception operations to support the German invasion of the United Kingdom (Operation Seelöwe). It would have involved an empty convoy of large transports threatening the east coast of England while the actual invasion force in small barges hit the southern coast.

Two days prior to the actual landings, the light cruisers Emden (Kapitän zur See Hans Mirow), Nürnberg (Kapitän zur See Leo Kreisch with Vizeadmiral Hubert Schmundt, the Commander of Cruisers, aboard) and Köln (Kapitän zur See Ernst Kratzenberg), the gunnery training ship Bremse and other light naval forces would escort the liners Europa, Bremen, Gneisenau and Potsdam, with 11 transport steamers, on Operation Herbstreise (Autumn Journey), a feint simulating a landing against the British east coast between Aberdeen and Newcastle. After turning about, the force would attempt the diversion again on the next day if necessary. (Most of the troops allocated to the diversion would actually board the ships, but disembark before the naval force sortied.)

Shortly before the commencement of "Sea Lion", the heavy cruiser Admiral Hipper (Kapitän zur See Wilhelm Meisel), on standby at Kiel from 13 September 1940, would carry out a diversionary sortie in the vicinity of Iceland and the Faroes.

The heavy cruiser Admiral Scheer (Kapitän zur See Theodor Krancke) would carry out another diversionary mission by raiding merchant shipping in the Atlantic. (It is doubtful this ship would have been available in time for the operation as she was undergoing extensive trials and crew training in the Baltic Sea following a major shipyard refit.)

So as you can see from the Wikipedia entry above this was no fly-by night operation that could be handled in a matter of hours it was a diversionary set of raids specifically planned to keep the RN capital ships busy and on the defencive for as long as possible.

The Royal Navy, for all that the doctrine was not always great, weren't morons either - the priority attack is the one towards the south coast, where most of the enemy will be coming from in any event due to the scale of the barge concentration and where the crossing time is much shorter.

And really any amphibious invasion - any at all, save for the invasion of Crete (which was a year or so later and hitting a lightly defended island) CANNOT rely on an air supply line. It is imperative to obtain a port, and do it soon - which is precisely what the RN can stop them doing.

The Kriegsmarine said in their official documents that the best they could do was a narrow landing - a "dash" as it were. The Heer demanded a wide landing, because to do otherwise would (they said) invite a speedy defeat because of it being easy to contain the narrow beach-head.

Part II of a report produced by GHQ Home Forces in the Autumn of 1940 says the following:

The Threat To Individual Commands

General
If the enemy decides to attempt invasion he will do it with the maximum possible strength. Whatever his commitments elsewhere, he will do his utmost to ensure that the forces required for invasion are available when he wants them. These forces might be anything up to 60 divisions. His resources of sea and air transport are far from sufficient to carry such a force in the first wave, and the initial landing force is not likely to exceed some 20-25 divisions. This figure will not decrease, and may increase as further ships are converted for invasion purposes and more special landing craft are constructed.

Eastern Command
At present the main threat is to Eastern Command owing to its geographical position in relation to Continental ports, and to the fact that the enemy can only provide maximum air cover up to the line The Wash-Bristol, and is likely to make his main effort within this protective zone.

Shipping in the appropriate ports at the present time is sufficient for 15-20 divisions, and some 4 smaller divisions could be transported by air. Any additional forces from the Baltic are likely to be directed against the Eastern and Northern Commands.

There is no reason why the threat to this Command should decrease numerically, though continued attacks on the Low Countries ports might make the assembly of an expedition more difficult, and the possibility of enemy success will diminish as the strength of our beach defences increases.

Southern Command
The threats at present to Southern Command are from attack, limited to 2 or 3 divisions, as far West as Portland in co-operation with any operations against Eastern Command, from diversionary sea-borne landings elsewhere, and from large scale air landings in the many suitable areas.

The sea-borne threat will only increase if the enemy is able to move large convoys down channel at will. There is no reason why the threat should decrease.

Now I know this is a passage from just one of many reports but does indicate to me that the British were expecting the main thrust of the German invasion to come on the Norfolk and Lincolnshire coasts with limited diversionary attacks on the South Coast and North East Coast. It just adds weight to the fact that it is doubtful the ships at Rosyth would be committed to the South Coast immediately.

As for the narrow landing it wasn't that narrow, shorter than the army wanted initially but longer than the beaches used in Normandy. The landings were to take place across an 80 mile front from Folkestone to Brighton.

 

[Saphroneth]

Which means that the German plan is to use a few light cruisers, one heavy cruiser and some transports (the transports being drawn from the small German Merchant Marine) to distract the ENTIRETY of Home Fleet. For days on end. Despite the fact that it's obvious the difference between a light cruiser and a heavy unit via air recon, meaning that it would be a feasible response to just dispatch the battlecruisers. This is literally what they were designed for - to destroy lighter units which had no prospect of damaging them.

German operational plans (especially naval ones) which rely on the enemy doing exactly what you want are no more guaranteed to succeed than Japanese ones - as per Midway...

And the reason why the RN thought it would be a silly idea to attack the south coast is that they could see the size of the shipping in the channel ports. Note that, while they expected the main blow to come in the east, they assumed that a diversionary attack of "two or three divisions" would come ashore in the south. Since the actual MAIN attack planned was about seven divisions, and without adequate supplies at first, this suggests that the RN actually got the shipping estimates not a million miles off.

There's another good reason, too. The geography of the south coast. It's basically beaches below bloody huge cliffs. THIS is probably the main reason why the Admiralty considered East of England the greater threat - with flatter terrain, it's actually much more suitable for amphibious operations. (Amphibious operations which the Brits, in general, had been thinking about for many years after Gallipoli taught lessons about what did not work.)
Germany, by contrast, had NO substantive experience in amphibious operations.

Let me make one thing clear - I don't think it impossible that the Germans might have and tried Sealion. I think it impossible (or vanishingly unlikely) it would be anything other than an utter debacle.
(The war-games of 1974 show this quite well - see the post I quoted. When assessing things thirty-four years on, they decided the only way to get a reasonably sized land battle was to mess with RN deployments to degrade them over OTL.)

 

[Ian Hathaway]

Which means that the German plan is to use a few light cruisers, one heavy cruiser and some transports (the transports being drawn from the small German Merchant Marine) to distract the ENTIRETY of Home Fleet. For days on end. Despite the fact that it's obvious the difference between a light cruiser and a heavy unit via air recon, meaning that it would be a feasible response to just dispatch the battlecruisers. This is literally what they were designed for - to destroy lighter units which had no prospect of damaging them.

German operational plans (especially naval ones) which rely on the enemy doing exactly what you want are no more guaranteed to succeed than Japanese ones - as per Midway...

And the reason why the RN thought it would be a silly idea to attack the south coast is that they could see the size of the shipping in the channel ports. Note that, while they expected the main blow to come in the east, they assumed that a diversionary attack of "two or three divisions" would come ashore in the south. Since the actual MAIN attack planned was about seven divisions, and without adequate supplies at first, this suggests that the RN actually got the shipping estimates not a million miles off.

There's another good reason, too. The geography of the south coast. It's basically beaches below bloody huge cliffs. THIS is probably the main reason why the Admiralty considered East of England the greater threat - with flatter terrain, it's actually much more suitable for amphibious operations. (Amphibious operations which the Brits, in general, had been thinking about for many years after Gallipoli taught lessons about what did not work.)
Germany, by contrast, had NO substantive experience in amphibious operations.

Let me make one thing clear - I don't think it impossible that the Germans might have and tried Sealion. I think it impossible (or vanishingly unlikely) it would be anything other than an utter debacle.
(The war-games of 1974 show this quite well - see the post I quoted. When assessing things thirty-four years on, they decided the only way to get a reasonably sized land battle was to mess with RN deployments to degrade them over OTL.)

Let me make one thing clear - my recent posts here are about my opinion that the Capital ships of the RN based at Rosyth are not going to magically appear on the South Coast to intercept the invasion barges ... nothing more, nothing less. The RN had sufficient strength to do that with the remains of its forces, the cruisers, destroyers and smaller vessels. If these can't stop the invasion then it's probably too late. In your original post #101 you seem to assume that there will be Capital ships from day one in the form of Aircraft Carriers, Battleships and Battle Cruisers. Even in the extract you posted in #106 it says:

The Admiralty did not intend the Home Fleet to move into the southern part of the North Sea unless heavy German vessels did (obviously, the Admiralty did not know exactly how weak the Germans were, and had to guard against a breakout into the Atlantic), reasoning that the forces already in place were more than adequate to do the business.

Which actually reinforces the point I was trying to make ... sorry for any confusion.

 

[Saphroneth]

Let me make one thing clear - my recent posts here are about my opinion that the Capital ships of the RN based at Rosyth are not going to magically appear on the South Coast to intercept the invasion barges ... nothing more, nothing less. The RN had sufficient strength to do that with the remains of its forces, the cruisers, destroyers and smaller vessels. If these can't stop the invasion then it's probably too late. In your original post #101 you seem to assume that there will be Capital ships from day one in the form of Aircraft Carriers, Battleships and Battle Cruisers. Even in the extract you posted in #106 it says:
Which actually reinforces the point I was trying to make ... sorry for any confusion.

Ah, I see.
Though it may not true to say that "if these can't stop the invasion it's probably too late", in that there's also the need for a supply line to be kept open (witness the trouble the Allies had in France on the 20 June when the weather impeded operations). But I certainly agree that the light forces were profligate in the channel.

(I recently ran into someone on another thread claiming that Sealion was more possible than Overlord, so some of that may have bled over onto you; for which I apologize.)

 

[TheYoungPretender]

Distraction... I'm not sure that word means what you think it means...

So a few ships are going distract the entire Home Fleet. Fascinating. Quite doable, if the Home Fleet in particular and the RN in general don't have, very deep in their DNA, for nearly three centuries by this point, that their one basic goal, underlying any others involving global empires, the Suez Canals, merchant fleets, et al. is that they are not to allow England to be invaded. This is what is switched into RN officers at Dartmouth starting at age fifteen. This has been their mission since "board the buggers with swords" was a viable tactical option.

They have an idea of how many surface units the Germans have. They know how many active ships the Germans have. They can send a force after any distraction force, and still have enough ships to gut an Sealion fifteen times over. A few cruisers dispatched to murder the Hipper does not detract from the ability of the rest of the Homefleet to put a fair sized chunk of Germany's domestic transport infrastructure and the tanks on it on the bottom of the English channel.

 

[Saphroneth]

So a few ships are going distract the entire Home Fleet. Fascinating. Quite doable, if the Home Fleet in particular and the RN in general don't have, very deep in their DNA, for nearly three centuries by this point, that their one basic goal, underlying any others involving global empires, the Suez Canals, merchant fleets, et al. is that they are not to allow England to be invaded. This is what is switched into RN officers at Dartmouth starting at age fifteen. This has been their mission since "board the buggers with swords" was a viable tactical option.

They have an idea of how many surface units the Germans have. They know how many active ships the Germans have. They can send a force after any distraction force, and still have enough ships to gut an Sealion fifteen times over. A few cruisers dispatched to murder the Hipper does not detract from the ability of the rest of the Homefleet to put a fair sized chunk of Germany's domestic transport infrastructure and the tanks on it on the bottom of the English channel.

THANK YOU.
It's astonishing how hard it is for people to grasp this sometimes - the Royal Navy's primary function is to defend Great Britain and Northern Ireland. Before that, it was to defend Great Britain and Ireland, before that it was to defend Great Britain, before that it was to defend England and Wales. (That's as far back as you can get before it's not really a familiar Royal Navy.)
And they're damned good at it. Indeed, I do not believe there has been a single successful seaborne invasion of Britain since the Royal Navy was formed. (Before anyone gets smart-assed ideas, the Glorious Revolution was only technically an invasion - it's a different class of events entirely when Parliament invites you in.)
The fact the Royal Navy only assigned destroyers and light forces to the Channel, OTL, does not mean that they felt that the capital ships were more important than preventing an invasion. It means that they felt that the DDs and MTBs and so on were sufficient. (As the navy with more invasions of various kinds under its belt than anyone else in history - yes, we've invaded over 80% of UN member states at some point - they had a better grasp than that most continental of all continental powers.)
If there's an invasion actually going on and the DDs and MTBs aren't doing enough, everything that can float is being rammed through the Channel in the most efficient way with guns blazing. Maybe they'll catch the first wave; maybe they won't. They'll certainly make sure there isn't a second wave, or a regular supply run, or anything of that nature, because the Germans have absolutely no way to stop anything larger than a destroyer except for hoping for a lucky torpedo hit from a submarine, or hoping for a lucky magazine hit from a bomb.
And they'll have to get lucky. A lot. In fact, they'll have to get this lucky.
(Based on June 1940)

BB:
Barnham
Nelson
Rodney
Valiant
BC:
Renown
Repulse
Hood
CV:
Ark Royal
Furious
CA:
Berwick
Devonshire
Norfolk
Sussex
Birmingham
Southampton
York
CL:
Aurora
Penelope
Cardiff
Galatea
Edinburgh
Glasgow
Newcastle
Southampton
Birmingham
Manchester
Sheffield
CL-AA:
Cairo


And all the Destroyers, of course. And the subs, which are at least familiar with the terrain. And the fact that any ship built since at least 1840 will be able to wreak a bloody harvest amongst those convoy barges which were never intended to face waves - let alone gunfire.

 

[sharlin]

C'mon Saph we all know the Germans would have made it work because you know....Germans and ummm...*jazzhands*.. reasons. But seriously you and Mr Pretender are utterly right.

 

[Daniel S. Fletcher]

Unspeakable Sea Mammal...

Got to post it <Mod edit of advertisement>

 

[Saphroneth]

<Mod edit of advertisement >

Okay, how the hell did they do that?
Seriously - if you advertize on the AH forum, you must explicate.

 

[Michele]

I notice how this thread, which was to be a glossary of Seelöwe threads, has become yet another Seelöwe thread, with advertising to boot. Or should I say to jackboot.

If anything, there's yet another recent thread under a camouflage title that should be listed here, but frankly I'm too lazy for that, sorry.

 

[Saphroneth]

I notice how this thread, which was to be a glossary of Seelöwe threads, has become yet another Seelöwe thread, with advertising to boot. Or should I say to jackboot.

If anything, there's yet another recent thread under a camouflage title that should be listed here, but frankly I'm too lazy for that, sorry.

I will. It's called Ready, Steady, GOOOOOOO!

 

[Soren]

Royal Navy dispositons mid September

In the hopes of this sticky being a useful source of information to refer to & not just a rehash of the fractious debates we already have........

Royal Navy dispositions in home waters from Pink List 16.09.40. National Archive ADM 187/9

Approx steaming time from Straits of Dover at 20 knots is given for each location in brackets. Destroyers with sweeping gear are indicated with *.

Dover (1hr)
2 MTB

Harwich (3.5hrs)
6 DD (Malcolm, Venerious, Verity, Wild Swan, Wivern, Worcester)
11 MTB

Portsmouth (3.5hrs)
1 CL (Cardiff)
14 DD (Beagle, Bulldog, Havelock, Harvester, Hesperus, Highlander Vanoc, Viscount, Saladin, Sturdy, Berkeley, Fernie, Mistral (FR))
5 TB (Branlebas, L'Incomprise, La Cordeliere, La Flore (FR), Z7 (Dutch))
6 MTB

Southampton (3.5hrs)
2 DD (Volunteer, Wolverine)

Sheerness/Chatham (4hrs)
2 CL (Galatea, Aurora)
18 DD (Brilliant, Icarus*, Impulsive*, Campbell, Venetia, Vesper, Vivacious, Walpole, Cattistock, Holderness, Garth, Hambledon, Vanity, Viriera*, Wallace, Westminster, Winchester, Wolsey)

London (4.5hrs)
1 MTB

Lowestoft (5hrs)
1 TB (Draug (Norwegian))
1 MTB

Portland (5hrs)
2 MTB

Plymouth
1 BB (Revenge)
2 CL (Newcastle, Emerald)
11 DD (Isis*, Broke, Vansihart, Whitehall, Westcott, La Melporiene (FR), Ouragan (FR), Bouclier (FR), Blyskawica (Pol), Burza (Pol), Garland (Pol))

The Humber (10hrs)
3 CL (Manchester, Southampton, Birmingham)
5 DD (Javelin*, Jupiter*, Jaguar*, Kelvin*, Watchman)
11 MTB

Milford Haven (14hrs)
1 TB (G13 (Dutch))

Roysth (18hrs)
2 BB (Nelson, Rodney)
1 BC (Hood)
3 CLAA (Bonaventure, Naiad, Cairo)
17 DD (Cossack, Maori, Sikh, Zulu, Jackel*, Kashmir*, Kipling*, Ashanti, Bedouin, Punjabi, Tartar, Electra*, Vortigen, Valorous, Vega*, Verdun*, Woolston)
1 TB (Sleipner (Norwegian))

Liverpool (18.5hrs)
3 DD (Vanquisher, Walker, Sabre)

Dundee (19hrs)
3 TB (Z5, Z6, Z8 (all Dutch))

Belfast (20hrs)
3 DD (Shikari, Scimitar, Skate)

Firth of Clyde (21.5hrs)
1 CL (Sheffield)
10 DD (Keppel, Achates*, Active*, Amazon*, Antelope*, Arrow*, Douglas, St. Laurent (RCN), Ottowa (RCN), Skeena* (RCN))

Scapa Flow (26hrs)
1 BC (Repulse)
1 CV (Furious)
2 CA (Berwick, Norfolk)
1 CL (Glasgow)
1 CLA (Curacoa)
7 DD (Somalia, Eskimo, Matabele, Duncan, Versatile, Vimy, Eglington

On patrol or escort duty
10 DD (Veteran, Witherington, Mackay, Hurricane, Winchelsea, Warwick, Witch, Wanderer, Vivien, Wolfhound)
1 TB (G15 (Dutch))

Auxiliary Patrol - from Wash to Selsey Bill approx 700 small patrol vessels of which 300 at sea at any one time.

Apologies for any typo's, I'm working from a written record taken from the internet several years ago & my typing is worse than my handwriting.

I'm curious if anyone has any information regarding readiness at port that could impact on the steaming times. Also manning on the French & Dutch vessels, were there really enough Free French/ Dutch manpower for there?

 

[CalBear]

Got to post it <Mod edit of advertisement>

NEVER, I repeat, NEVER do this again.

You want to put something in you sig, more power to you.

This isn't an advertising site.

 

[Daniel S. Fletcher]

NEVER, I repeat, NEVER do this again.

You want to put something in you sig, more power to you.

This isn't an advertising site.

Calm your passions I hereby advise - crucially, not advertise - cannabis.

My most humble and effusive apologies for posting about an alternate history book involving Operation Sealion on an alternate history website called alternatehistory.com in a thread dedicated to Operation Sealion. I will NEVER, I repeat, NEVER do that again.