Sealion!

varyar · Dec 29, 2009

(Wait, wait, bear with me here...)

WI, by some perversity, Adolph Hitler decides, against all advice, cajoling, pleading, reason, etc. to launch Operation Sealion in the fall of 1940?

On September 17, the barges are loaded, the Kriegsmarine sallies forth, the Luftwaffe hurls everything it has at southern England...

It's a miserable failure, of course, a catastrophe of the first order.

The first wave, consisting of divisions from 9th and 16th Armies, is almost entirely wiped out still at sea. A handful of very fortunate barges make it all the way to the English coast, where their lucky occupants are immediately taken prisoner by British forces - for them, at least, the war is over. (One small town near Bexhill is briefly seized by a German platoon. This victory, lasting about half an hour, is the only thing approaching good news for the Germans that day.)

In the skies, the Luftwaffe fighter wings take a pounding. The British push some of their squads from 12 and 13 Groups into the battle, recognizing the golden opportunity that Hitler has given them. The German Navy likewise suffers very heavy losses.

All in all, not a very good day for the Third Reich.

***

So, now what happens? Can Hitler somehow keep power - or his life - after the debacle?

BlairWitch749 · Dec 29, 2009

In the worst case scenario of a total disaster the Germans lose a couple hundred air craft and maybe 6-9 divisions and their surface fleet (which lets face it after the sinking of Bismark didn't do anything anyway). This doesn't materially change their status as a war making power as Germany had well over 100 divisions and could produce more aircraft as needed (pilot replacement was their main problem but perhaps such a disaster might actually inspire them to fix that issue)

The British wouldn't be in any better position necessarily and infact fear of a renewed invaison might deter them from heavily reinforcing the med and or keeping more divisions in reserve for the home army and more RN ships for home defense and more RAF squadrons for home defense

Der Manstein Kommt which I will be updating this week will give a much more scary scenario

The idea that the Germans after 1 bad operation (even an operation that cost them 10 divisions) would fall apart is ASB. They fought for 2 and a half years after Stalingrad and Tunis where they lost the equivilent of 30+ divisions in a single campainging season)

The Kiat · Dec 29, 2009

What surface fleet? The Germany Navy of WWII was a joke; it was just about weaker than the High Seas Fleet of a generation before.

HJ Tulp · Dec 29, 2009

The German economy grinds to a halt somewhere in the year 1942 at the most as a keypart of the European transport system (riverine and canal transport) lies at the bottom of the Channel.

BlairWitch749 · Dec 29, 2009

HJ Tulp said:
The German economy grinds to a halt somewhere in the year 1942 at the most as a keypart of the European transport system (riverine and canal transport) lies at the bottom of the Channel.

You must be joking. they would just build more barges and shift traffic to road and rail bridges... whilst there might be something of a temporary disruption or slow down they would improvise their way around it... the germans were able to supply troops (albiet with varrying degrees of success) over 1500 kilometers from primary bases along partisan infested roadways and your saying they couldn't handle their Rhine and inland waterway fleet being out of action for some time

esl · Dec 29, 2009

If any of you actually did any research, you'd know that the RN didn't have the firepower to sink more than one vessel per every three attacking sortie, which means the basic math doesnt add up. Attacking convoys was very difficult to pull of even if the bulk of any escorting vessels were auxiliary warships. Most German convoys escaped allied naval attacks unharmed well into the middle of the war.

10 RN cruisers of which about 6 are available.

75 RN Destroyers of which 2/3 are available [56]

750 RN trawlers of which only 1/3 are gun armed and only 1/3 are available due to rotation.

Thats at most 159 sortie per day in the south coast region with maybe 50-60 German vessels sunk per day.

RAF is worse with CEP of 5km against coastal targets and 20miles against targets in Germany.

They are unlikely to do better than history. In one week they destroyed 65 German barges/vessels in port and damaged another 200, which were repaired within a week....and that was inconjunction with RN port attacks

Utterly useless considering the German invasion fleet counted 4000 vessels and 320 naval vessels. Germany had more than 700 naval vessels at this time in the war.

Nobodys going to sweep the invasion from the channel , thats just standard british propaganda

All the Germans need to do is to with hold magnitic mines to only KM deployment and then none would have been dropped a ashore prior to the invasion and transfere the crews of the Scharnhorst and Gneiseau to the Bismarck and Prince Engen give them a couple of weeks shake down cruise and let them loose ahead of the invasion to decoy the Home fleet away....something they did all the way through the 1920s and 1930s. Combined with the Hipper and possible Scheer sortie, that would have been more than sufficent to force all available Home fleet assets to deploy. So the Home fleet would have been decoyed away ahead of time... and the mine barrier would have bottled up the RN inflicting unacceptable losses

varyar · Dec 29, 2009

Never post in the morning, that's my lesson from this...

Cockroach · Dec 29, 2009

esl said:
If any of you actually did any research, you'd know that the RN didn't have the firepower to sink more than one vessel per every three attacking sortie...

I. How are you defining an 'attacking sortie'? There's a lot of options for using it to weasel out... I mean, for example, if you're defining 'attacking sotrie' as British vessels put to sea on vauge rumor of German naval activity then there's bound to be a low sinking rate.
II. Source?

So the Home fleet would have been decoyed away ahead of time... and the mine barrier would have bottled up the RN inflicting unacceptable losses

Only if said mine belt spontanously pops into existance the day before the landing...

CalBear · Dec 30, 2009

I have to say your comment about doing research made my day, totally hilarious. Since your's seems to be a bit light, here a few figures for you to chew on.

Six cruisers set loose among a herd of barges (which are under tow BTW), would be a slaughter of horrific proportions. Every weapon on the ship, down to the light AAA is deadly to open barges.

If we are talking a York class heavy cruiser, it carried 1050 8" rounds, 800 4" rounds, and 20,000 .50 cal rounds. For actual ship size targets it also carried 6 21" torpedoes. If we are talking a Leander class light cruiser, it carried 2,000 6" rounds (rated capacity, actual was as much as 40% greater), 800 4" rounds, and 30,000 .50 cal rounds. For actual ship size targets it also carried 8 21" torpedoes.

You look at those figures and think REALLY hard on how one of those cruisers is going to need three sorties (or between 84,000 and 117,000 rounds) to kill a barge.

I also note that you sort of forgot to mention the Home Fleet's half dozen or so BATTLESHIPS & Battle Cruisers. Nelson & Rodney (which were both sitting in Rosyth anticipating the invasion attempt), as an example, carried 940 rounds of 16" ammunition, 1,800 rounds of 6" ammo, 1,050 4.7" rounds, 36,000 rounds for the 2 pdr (39mm) QF, and 30,000 .50 cal. That is just a touch over 68,000 rounds. How many barges & tow boats you figure that will chop up?

Per usual, your data simply doesn't add up. That, of course, is what happens when you take a data set and apply it to a vastly different enviroment.

esl said:
If any of you actually did any research, you'd know that the RN didn't have the firepower to sink more than one vessel per every three attacking sortie, which means the basic math doesnt add up. Attacking convoys was very difficult to pull of even if the bulk of any escorting vessels were auxiliary warships. Most German convoys escaped allied naval attacks unharmed well into the middle of the war.

10 RN cruisers of which about 6 are available.

75 RN Destroyers of which 2/3 are available [56]

750 RN trawlers of which only 1/3 are gun armed and only 1/3 are available due to rotation.

Thats at most 159 sortie per day in the south coast region with maybe 50-60 German vessels sunk per day.

RAF is worse with CEP of 5km against coastal targets and 20miles against targets in Germany.

They are unlikely to do better than history. In one week they destroyed 65 German barges/vessels in port and damaged another 200, which were repaired within a week....and that was inconjunction with RN port attacks

Utterly useless considering the German invasion fleet counted 4000 vessels and 320 naval vessels. Germany had more than 700 naval vessels at this time in the war.

Nobodys going to sweep the invasion from the channel , thats just standard british propaganda

All the Germans need to do is to with hold magnitic mines to only KM deployment and then none would have been dropped a ashore prior to the invasion and transfere the crews of the Scharnhorst and Gneiseau to the Bismarck and Prince Engen give them a couple of weeks shake down cruise and let them loose ahead of the invasion to decoy the Home fleet away....something they did all the way through the 1920s and 1930s. Combined with the Hipper and possible Scheer sortie, that would have been more than sufficent to force all available Home fleet assets to deploy. So the Home fleet would have been decoyed away ahead of time... and the mine barrier would have bottled up the RN inflicting unacceptable losses

jkay · Dec 30, 2009

Sorry, varyar. Your probably didn't know it, but the Sea Mammal That Shall Not Be Named is a pretty delicate subject around here, easily bringing the flaming posters until the thread's nothing but a crisp.

Bye-bye, thread!

Astrodragon · Dec 30, 2009

jkay said:
Sorry, varyar. Your probably didn't know it, but the Sea Mammal That Shall Not Be Named is a pretty delicate subject around here, easily bringing the flaming posters until the thread's nothing but a crisp.

Bye-bye, thread!

Indeed!
Nuke 'em till they glow, then shoot the radiant fat sea mammal in the dark....

BlairWitch749 · Dec 31, 2009

CalBear said:
I have to say your comment about doing research made my day, totally hilarious. Since your's seems to be a bit light, here a few figures for you to chew on.

Six cruisers set loose among a herd of barges (which are under tow BTW), would be a slaughter of horrific proportions. Every weapon on the ship, down to the light AAA is deadly to open barges.

If we are talking a York class heavy cruiser, it carried 1050 8" rounds, 800 4" rounds, and 20,000 .50 cal rounds. For actual ship size targets it also carried 6 21" torpedoes. If we are talking a Leander class light cruiser, it carried 2,000 6" rounds (rated capacity, actual was as much as 40% greater), 800 4" rounds, and 30,000 .50 cal rounds. For actual ship size targets it also carried 8 21" torpedoes.

You look at those figures and think REALLY hard on how one of those cruisers is going to need three sorties (or between 84,000 and 117,000 rounds) to kill a barge.

I also note that you sort of forgot to mention the Home Fleet's half dozen or so BATTLESHIPS & Battle Cruisers. Nelson & Rodney (which were both sitting in Rosyth anticipating the invasion attempt), as an example, carried 940 rounds of 16" ammunition, 1,800 rounds of 6" ammo, 1,050 4.7" rounds, 36,000 rounds for the 2 pdr (39mm) QF, and 30,000 .50 cal. That is just a touch over 68,000 rounds. How many barges & tow boats you figure that will chop up?

Per usual, your data simply doesn't add up. That, of course, is what happens when you take a data set and apply it to a vastly different enviroment.

Calbear, there exists some question as to whether or not the British would actually committ battleships to the channel (Nelson getting mined and Royal Oak getting torpedeoed were not lost on Churchill) As well the British ability to read signals via ultra was not anywhere near as advanced as it would be in 1942 and beyond (The British feared invasion on the east coast as far as Norwich all the way to the west of Portsmouth and had a lot of their reserve spread out)... the battleships were in place to deter an east coast invasion but even if you assume they would brave the channel;

British gunnery on their ships was not notably impressive in 1940 (ie all the wasted shells at Bismark which was a huge stationary target) and how many of the sailors and officers had relavent combat experience. how many were reservists or without adequate training?

I don't know if esl's kill ratio is too conservative but the idea that somehow their accuracy would be so great that they would have multiple kills per sortie seems a bit stretched to me; I am only aware of a few capital British ships from 1940 having notably good gunnery records (Renown and Warspite seemed to have been well served)

Zyzzyva · Dec 31, 2009

BlairWitch749 said:
Calbear, there exists some question as to whether or not the British would actually committ battleships to the channel (Nelson getting mined and Royal Oak getting torpedeoed were not lost on Churchill) As well the British ability to read signals via ultra was not anywhere near as advanced as it would be in 1942 and beyond (The British feared invasion on the east coast as far as Norwich all the way to the west of Portsmouth and had a lot of their reserve spread out)... the battleships were in place to deter an east coast invasion but even if you assume they would brave the channel;

British gunnery on their ships was not notably impressive in 1940 (ie all the wasted shells at Bismark which was a huge stationary target) and how many of the sailors and officers had relavent combat experience. how many were reservists or without adequate training?

The British wouldn't deploy the battleships? Are you nuts? This is D-Day, H-Hour, the Moment of Truth. This is the single, solitary event for which the Home Fleet had been built. This is what they were going to call all the RAF squadrons hiding up north south for, and this is what they would move every available man and gun to Dover for.

Nelson, Rodney, and every other ship that can get there in time is going there.

BlairWitch749 · Dec 31, 2009

Zyzzyva said:
The British wouldn't deploy the battleships? Are you nuts? This is D-Day, H-Hour, the Moment of Truth. This is the single, solitary event for which the Home Fleet had been built. This is what they were going to call all the squadrons hiding up north south for, and this is what they would move every available man and gun to Dover for.

Nelson, Rodney, and every other ship that can get there in time is going there.

The home fleet is the sword and shield of the Brittish empire. Sending battleships in daylight (night bombardments are only going to be partially effective and with the critical battle they need every shell to be deadly). Is a huge risk to mines, subs, coastal artillery and aircraft. The RAF was stretched to the limit guarding the home islands and would be stretched even more so by actual German landings and it would be nearly impossible for them to detail fighter escorts to the fleet.

The Germans had pulled their Stukas off the line after their first couple of disaster sorties against the English homeland... there were more than 300 of them in reserve to support the landings which could be diverted to attack the home fleet. We have discussed in other threads the lack of German heavy bombs in the summer of 1940 however the SC250 of which the JU-87B could carry in pairs would be sufficient to cause damage to a battleship (not necessarily a threat to sink them but if you hit the decks with 250kg's of high explosive enough times you are going to drive the ship out of the fight or disable enough crew or gun positions to make the ship combat ineffective)

The effect of Stuka's on heavy warships off the coast of Crete in 1941 shouldn't be discounted

Churchill was determined to fight on even if the home islands fell (ie continue the war from canada) and the loss of battleships or sizeable portions of the home fleet would make that nearly impossible

BlackWave · Dec 31, 2009

The RAF wasn't tiny nor pathetic and nor would German landings be overly fast or massive. A German landing of such scale would be rich pickings for both the RAF, ground guns, and battleships. Only quite inept intelligence and logistics on the part of the Limeys would circumnavigate that.

BlairWitch749 · Dec 31, 2009

BlackWave said:
The RAF wasn't tiny nor pathetic and nor would German landings be overly fast or massive. A German landing of such scale would be rich pickings for both the RAF, ground guns, and battleships. Only quite inept intelligence and logistics on the part of the Limeys would circumnavigate that.

The RAF was able to hold sway over London because of the short range of the ME-109... farther to the south the conditions were much closer to parity(not superiority required for sealion necessarily but the farther south the battles took place the more combat manuevering and time could an ME-109 pilot put in.) The British left all their artillery pieces and tanks at Dunkirk and would have been hard pressed to break up a lodgement with ground forces.
Their intillegence WASN'T all powerful at that time and they had to defend the east coast and the western portions of the channel coast so there would be critical days required before they could concentrate strength against a beachead.
The British home army was in no condition to fight open battle with the German army... the only thing they could hope and pray for would be for the Royal Navy to interdict supplies and reinforcements so that any beachhead could be starved out.
A lot of people on the board like to point out the virtues of the home guard and that they would somehow be a serious obstacle to landed German forces...militia divisions had an extremely poor record in WW2 including Stalin's people's militia divisions and the volksgrenadiers... the home gaurd gets a pass because they were never tested but I have never heard anything compelling to say that they would perform better

BlackWave · Dec 31, 2009

Even if the German army did get ashore, the RAF could rain death upon them, and then we must consider how many losses they would take actually getting ashore--landing boats were not the Kriegsmarine's speciality. I'm sure CalBear or someone can express what I'm getting at in greater detail.

CalBear · Dec 31, 2009

BlairWitch749 said:
Calbear, there exists some question as to whether or not the British would actually committ battleships to the channel (Nelson getting mined and Royal Oak getting torpedeoed were not lost on Churchill) As well the British ability to read signals via ultra was not anywhere near as advanced as it would be in 1942 and beyond (The British feared invasion on the east coast as far as Norwich all the way to the west of Portsmouth and had a lot of their reserve spread out)... the battleships were in place to deter an east coast invasion but even if you assume they would brave the channel;

British gunnery on their ships was not notably impressive in 1940 (ie all the wasted shells at Bismark which was a huge stationary target) and how many of the sailors and officers had relavent combat experience. how many were reservists or without adequate training?

I don't know if esl's kill ratio is too conservative but the idea that somehow their accuracy would be so great that they would have multiple kills per sortie seems a bit stretched to me; I am only aware of a few capital British ships from 1940 having notably good gunnery records (Renown and Warspite seemed to have been well served)

British gunnery wasn't spectacular, especially in the open waters of the North Atlantic when in action against warships that were also maneuvering at 25+ knots (although it was good enough to more or less wipe out the KM in Norweigen water despite fairly stupid deployments). In the Channel, against 10 knot towed open barges, the scenario shift considerably. The German plans called for what were more or less towed target sleds crossing a 20+ mile body of water. Even poorly drilled gun crews performance will be markedly improved in those conditions. I would fully expect the majority of the sinkings to be the result of fire from secondary and AAA batteries on the heavies, with the main batteries being used against the port locations and assembly points

Put the Nelson & Rodeny in the middle of the Channel about 15 miles apart and draw a circle with a 21 mile radius around each ship and a second circle with a radius of 15 miles, or put one five miles off Dover and the other 10 miles off Portsmouth with the same circles) and see what area they dominate. The 15 mile circle is for the secondary six inch battery. For that matter picture either one of these mosters (or the Hood which was waiting with them in Scotland) sailing at about 20 knots with a couple destroyers as escorts through the barge daisy chains as they are under tow.

Not a pretty picture.

Dan Reilly The Great · Dec 31, 2009

BlackWave said:
Even if the German army did get ashore, the RAF could rain death upon them, and then we must consider how many losses they would take actually getting ashore--landing boats were not the Kriegsmarine's speciality. I'm sure CalBear or someone can express what I'm getting at in greater detail.

Quite right, it's not my expertise, but as I recall a fall invasion would have hit some rough seas in the channel, and the river barges were not the most stable or seaworthy vessels. I think it is quite reasonable to assume that at least several if not more barges would have been swamped or capsized during the invasion.

Also the Germans would not have enjoyed local air superiority, so their invasion force would have quickly suffered heavy losses as the RAF starts chewing them up from the sky. They most definetly could not have maintained decent logistics, and the RN far outclassed the KM in surface engagements. Even if the British forces located on the mainland were insufficient to hold the Germans on the beach by force of arms, the heer is gonna have a hard time moving off the beach without the ability to resupply or reinforce their beachhead.

BlairWitch749 · Dec 31, 2009

CalBear said:
British gunnery wasn't spectacular, especially in the open waters of the North Atlantic when in action against warships that were also maneuvering at 25+ knots (although it was good enough to more or less wipe out the KM in Norweigen water despite fairly stupid deployments). In the Channel, against 10 knot towed open barges, the scenario shift considerably. The German plans called for what were more or less towed target sleds crossing a 20+ mile body of water. Even poorly drilled gun crews performance will be markedly improved in those conditions. I would fully expect the majority of the sinkings to be the result of fire from secondary and AAA batteries on the heavies, with the main batteries being used against the port locations and assembly points

Put the Nelson & Rodeny in the middle of the Channel about 15 miles apart and draw a circle with a 21 mile radius around each ship and a second circle with a radius of 15 miles, or put one five miles off Dover and the other 10 miles off Portsmouth with the same circles) and see what area they dominate. The 15 mile circle is for the secondary six inch battery. For that matter picture either one of these mosters (or the Hood which was waiting with them in Scotland) sailing at about 20 knots with a couple destroyers as escorts through the barge daisy chains as they are under tow.

Not a pretty picture.

Rodney and others missed a lot of shots on Bismark after her rudder was disabled... the British destroyers did an excellent job at Norway... but the record of the capital ships wasn't as impressive this was also to be expected because the destroyers had a lot of wartime sorties for convoy escort work and had a higher proportion of seasoned personel because of that

The middle of the channel reduces the range of coastal artillery in the pas de calais down to 15 miles (which 155mm guns or larger) could hit from a fixed position with relative impunity (the raf had almost no tactical bombing assets in summer in 1940 and were too stretched to committ fighter escorts nor are the spotting aircraft which the British battleships relied on going to be able to operate in skies over the channel full of ME-109s and ME-110s.