My Attempt on a Successful Sealion
- Thread starter Berra
- Start date
No, the Germans would still be faced with the insurmountable problem of launching a seaborne invasion that would have to take place at night against the then massive Royal Navy. Sealion ,without a massive reduction in the naval odds facing the Germans ,is a non-starter.
You don't need radar to see that the Germans have massed their ships and loaded their barges. This can be done by aerial recon or agents on the ground. The British fleet can still crush any attempt to cross. And what's the range of "good" German radar. The British bases can be a litle further back and they can still intercept German planes spotted by observers. Granted, British losses are higher and German are lower, but overall the air battle would still favor the British. Sea Lion is still a failure - and Hitler sends more planes against London for vengence, so his loses are greater than OTL.
Sealion just couldnt work.It was way over the top.Thing is,the Kreigsmarine was outgunned like 6-1 by the Royal Navy.Couldnt have made it across I think,and even if it did,it would be immediatedly cut off and surrounded.The Germans would lose a lot crossing the Channel,then they would have to storm the beaches,(I guess they would manage to break through and establish a beachhead)but they wouldnt manage to breakout of the foothold.What the British would do is quickly surround the Germans with superior forces to hold them in place,then just attack them till they ran out of ammo and food(not long,they would be cut off from further reinforcement and supply due to Allied maritime superiorioty.Further,since the battle of britain went in favor of the RAF,the Luftwaffen would have a really hard time trying to airlift in extra supplys,a lot of them would get shot down.)Also,unlike the US which figured out how to use parachutes to drop troops out of planes,the Germans had tried to use gliders,which failed miserably.So no airlifting in the Waffen SS to help out.For the Germans to airlift any new troops at all into Britain,you would have to have them secure and defend airbases in England,with German planes flying across the Channel,make it across,then manage to effectively establish themselves with very little extra fuel and ammo able to get to them.The RAF would just fall back into the middle of the country,or Scotland,then bomb them from there with the overwhelming numerical superiority they would have over the small amount of planes able to move across the Channel.
Even if the Germans manage to do the close to impossible and capture London,I can see Churchill refusing to surrender and trying a National Redoubt of sorts further north.(Not impossible,the Brits could have fought on even if London was taken.)Also,unlike the French absurdly calling upon places like Algeria and St.Kitts and Nevis to fight on,the British Empire could continue to resist even IF all of britain is taken.Australia,India,Canada could stay in the fight for some time.
What will probably happen is this-Germany launches the invasion force.Germany launches a almost all of its force of ships and planes to try to soften up southeastern England first.Bad idea.RN overwhelms the German fleet,surrounds and destroys as much as half the whole German Navy in a huge naval battle that dwarfs anything else in the war.With fleet protection gone,time is tough for the landing barges,which lose the majority of there number on the way to England.The Lufftwaffen tries to guard the ships in by bombing the British fleet,but that fails completely,Nazi Germany,powerful though it was,did not know a thing about naval aviation.The German air force was built to serve as a terror campaign weapon,dropping tons of inaccurate bombs on enemy cities.Trying to get them to aim at moving ships is beyond there capacity.The RAF swoops down and kills countless numbers of them,the severe loss of material will be felt sorely later in the war.Still,through sheer numbers,the Germans manage to blow up some English ships,which hurts them,but the losses are heavily on the German side.Finally,thanks to the massive number of troops Hitler throws in the battle,a good number of them manage to land on the shore.Initially things go well enough,the kill ratio is about 1:1 and the Germans manage to establish a small beachhead.However they are quickly surrounded by the British forces,which have moved into the area ahead of time as the battle in the Channel rages.The Germans try to break for London but they are stopped somewhere south of it with heavy casualties.For another two weeks or so,the British skirmish with them,beating down the force now demoralized and running out of ammo,even food.Finally,they mount one major assault on the Germans,and they are in no condition to defend themselves.They surrender and England takes more than a half million prisoners.This becomes the turning point in the war,same way Stalingrad was in OTL.
Even if the Germans manage to do the close to impossible and capture London,I can see Churchill refusing to surrender and trying a National Redoubt of sorts further north.(Not impossible,the Brits could have fought on even if London was taken.)Also,unlike the French absurdly calling upon places like Algeria and St.Kitts and Nevis to fight on,the British Empire could continue to resist even IF all of britain is taken.Australia,India,Canada could stay in the fight for some time.
What will probably happen is this-Germany launches the invasion force.Germany launches a almost all of its force of ships and planes to try to soften up southeastern England first.Bad idea.RN overwhelms the German fleet,surrounds and destroys as much as half the whole German Navy in a huge naval battle that dwarfs anything else in the war.With fleet protection gone,time is tough for the landing barges,which lose the majority of there number on the way to England.The Lufftwaffen tries to guard the ships in by bombing the British fleet,but that fails completely,Nazi Germany,powerful though it was,did not know a thing about naval aviation.The German air force was built to serve as a terror campaign weapon,dropping tons of inaccurate bombs on enemy cities.Trying to get them to aim at moving ships is beyond there capacity.The RAF swoops down and kills countless numbers of them,the severe loss of material will be felt sorely later in the war.Still,through sheer numbers,the Germans manage to blow up some English ships,which hurts them,but the losses are heavily on the German side.Finally,thanks to the massive number of troops Hitler throws in the battle,a good number of them manage to land on the shore.Initially things go well enough,the kill ratio is about 1:1 and the Germans manage to establish a small beachhead.However they are quickly surrounded by the British forces,which have moved into the area ahead of time as the battle in the Channel rages.The Germans try to break for London but they are stopped somewhere south of it with heavy casualties.For another two weeks or so,the British skirmish with them,beating down the force now demoralized and running out of ammo,even food.Finally,they mount one major assault on the Germans,and they are in no condition to defend themselves.They surrender and England takes more than a half million prisoners.This becomes the turning point in the war,same way Stalingrad was in OTL.
Since I beleave that each member deservs one attempt on a sucessful Sealion, here I go:
Could a good German radar system and no Brittish radar be big enough change to make the impossible possible?
[Run for cover and blame Thande]
Nope. The best thing for the Germans is to have over 200 U-Boats from 1939 & then doubling this number by the time of the invasion. And just as importantly they introduce a blockade of the UK in the early months of 1940.
Also the Germans would need to:
A) Focus on building up a stronger navy early on--say the late 1930s--and not just rely on U-boats, potent as they may be. Also helps to defend the (occupied) French fleet from being attacked by the Brits.
B) Change strategy. The Germans hoped that after the fall of France, England would simply sue for peace, and thus an invasion, i.e. SeaLion, would not be necessary. Churchill, however, was not interested in such a 'peace', and thus Germany had to come up with another plan...and focused their attention more toward the East anyway.
A) Focus on building up a stronger navy early on--say the late 1930s--and not just rely on U-boats, potent as they may be. Also helps to defend the (occupied) French fleet from being attacked by the Brits.
B) Change strategy. The Germans hoped that after the fall of France, England would simply sue for peace, and thus an invasion, i.e. SeaLion, would not be necessary. Churchill, however, was not interested in such a 'peace', and thus Germany had to come up with another plan...and focused their attention more toward the East anyway.
davidr151
Banned
What would have happened if the Germans discovered that the British were reading the enigma code? That would not allow them to invade Britain right away but if they reequipped their subs with a code the British could not crack, the Germans could have won a war of attrition by slowing blockading Britain and forcing them out of the war.
Any thoughts?
Any thoughts?
Roddoss72
Banned
First and foremost for the success of Operation Seelowe to go ahead would be the state of mind of Fuhrer Adolf Hitler. Adolf Hitler was never convinced of an invasion of Britain as he was with Poland, Norway, Denmark, Belgium, The Netherlands and France where he was stoic in his conviction that they needed to be invaded, but when it came to Britain he believed that Britain would seek peace without launching an invasion, big mistake.
In an alternate senario, Fuhrer Adolf Hitler issues his Fuhrerdirective with a clear cut understanding that German forces will invade, and not if they invade. At the time of the rescue of the BEF and French Britain had only three fully equipped infantry divisions in London the rest of the Army was of Regiment or Battalion strength, and no fit shape to prevent an invasion.
The Luftwaffe is allowed during Operation Alder phase to attack radar and airfields two days running with continual follow-up attacks, Goering actually forbade any attack on airfields and radar installations two day in a row, also the Luftwaffe should have attack major transportation hubs such as Ashford and Canterbury as this would prevent movement of troops to the beachheads of Kent (Dover, Folkestone and Hythe), also major attacks on porst that would play a major role in anti-invasion interdiction.
Another failure was of Adolf Hitler was not getting the Vichy French to declare war on Britain after the attack on her fleet by Taskforce H at Oran and Mers-el-Kebir, and using as many Vichy French ships as he could for invasion fleet duties, and also the 2,700 aircraft that the Vichy French had, and also not including the Italian air force to contribute numbers, plus using the Italian Navy in invasion duties, this is exactly what i would have done.
I am currently working on a senario of a successful Axis invasion of Britain.
In an alternate senario, Fuhrer Adolf Hitler issues his Fuhrerdirective with a clear cut understanding that German forces will invade, and not if they invade. At the time of the rescue of the BEF and French Britain had only three fully equipped infantry divisions in London the rest of the Army was of Regiment or Battalion strength, and no fit shape to prevent an invasion.
The Luftwaffe is allowed during Operation Alder phase to attack radar and airfields two days running with continual follow-up attacks, Goering actually forbade any attack on airfields and radar installations two day in a row, also the Luftwaffe should have attack major transportation hubs such as Ashford and Canterbury as this would prevent movement of troops to the beachheads of Kent (Dover, Folkestone and Hythe), also major attacks on porst that would play a major role in anti-invasion interdiction.
Another failure was of Adolf Hitler was not getting the Vichy French to declare war on Britain after the attack on her fleet by Taskforce H at Oran and Mers-el-Kebir, and using as many Vichy French ships as he could for invasion fleet duties, and also the 2,700 aircraft that the Vichy French had, and also not including the Italian air force to contribute numbers, plus using the Italian Navy in invasion duties, this is exactly what i would have done.
I am currently working on a senario of a successful Axis invasion of Britain.
Firstly, Sealion is not impossible, but merely improbable, given the situation. However, if you take a Point of Divergance of Goring being killed in a car crash, or some other mean of death in 1935, you could cure the German Air force of impracticality. But that doesn't mean that you could launch a successful Sealion even 50 percent of the time, rather it allows the Germans to get air superiority. Another necessity is luring the RN away from the Home Islands. If that works then you have say a 49 percent chance of a successful Sealion, as you have to take into account of the logistics, and where the Germans land.
The closest to getting to a successful Sealion IMO is this timeline here: https://www.alternatehistory.com/discussion/showthread.php?t=35189
Note that even this isn't the true Sealion that we all love and to brag how it can't possibly work.
They say that Saying the Sealion is dangerous... Then again, I love danger.
The closest to getting to a successful Sealion IMO is this timeline here: https://www.alternatehistory.com/discussion/showthread.php?t=35189
Note that even this isn't the true Sealion that we all love and to brag how it can't possibly work.
They say that Saying the Sealion is dangerous... Then again, I love danger.
The destruction of the RAF makes Sealion possible but the continued existance of the RN means any German attempt will end in failure.
Once the war has been Sea Lion is pretty much toast. As for being creative before that. 1932 start the German-British export company. Use it to slowly sneak into Britain a whole bunch of weapon stashes. During Dunkirk when all those little boats were getting the British army out of france, add more little boats to all the confusion. Saboteurs dressed as British military. They attack the radar stations, navy bases, RAF. When the battle of Britain happens no targeting civilian areas, waist of military resources. Attack the RAF and use troop transport aircraft to bring in more troops. Britain has a long coast line, use the subs to bring in more supplies. Also use the subs to capture British cargoe ships, put German troops on board and continue on to Britain. The ships already have military supplies on board comming from America. Once Britain is in enough trouble, launch a full scale invasion. Also assasinate Churchill, he could probably figure out how to counter all this so for it to work, he needs to have a accident.
Why does Schleicher want to invade Britain?
What is HM Customs & Excise doing while all this is going on? Not to mention Scotland Yard, the Special Branch, and the SIS?
And have a fun time explaining themselves once they get there.
Now add the LDV to the cohort of those doing nothing. How do they find these establishments, seeing as they don't know where anything is and there aren't any signposts to show them the way?
The RAF has the nasty ability to shoot back. Bringing in troop transports under these circumstances is a good way to lose a few Tante Ju's.
Also people who can make rude things called telephone calls to Coastal Command. Also Coastal Command, which has unpleasant things like depth charges. And the North Sea isn't the quietest, most untenanted place in the ocean.
Also gun crews and wirelesses to warn that something is going on. The crew of a Type VII U-Boat is 42-52 men. You have to 1) run the boat 2) run the ship 3) have enough soldiers to make a difference. Oh yes, and what if the cargo ship is in a convoy, as almost all were?
One might call it "Victorious German Arms" Syndrome, after the pamphlet by Gary Gygax (yes, the co-designer of Dungeons & Dragons^tm). This was a WI where the Germans made all the right decisions and not only did the Allies not make any, they couldn't respond differently to anything the Germans did.
If the RAF don't got no radar , they are toast in BoB , as are the RN toast in Channel. As it was, it was only the Radar that allowed RAF 'Ground Controlled Intercept' to occur ,thus avoiding costly CAP missions that would have cut the available fighter force at least in half. With ½ the RAF fighter force you get ½ the kills so the Germans average 2:1 kill ratio through the start of BoB. There will be no 'big wing', if there is not a hour's warning through radar, to build up such a wing, thus no shift from 1:1 to 2:1 in the RAF favor. Instead as the RAF fighter losses mount the Luftwaffe kill ratio would climb above 2:1 in their favor.
As it was ,after just one week of Stuka bombings at Dunkirk in 'Operation Dynamo', at most only 1/3 of the RN destroyers were still operational.... and that was with just 200 Stuka and the beginning effects of ‘fatigue’ from continuous sortie, was just starting to kicking in.
Over a ten day period around ‘Operation Dynamo’, the RN/Allies lost 23 Destroyers crippled or sunk and another 22 damaged and out of operations for at least a week. In addition they lost 42 trawlers/MS/Steamers crippled or sunk and another 16 damage. All from only 200 Stuka. The RAF fought to protect their fleet but lost 177 planes to the Germans loss of only 132 planes.
In the actual Sealion plan , the invasion was to be launched only after 8-10 days of bombing of RN fleets and ports. Given how freely the Luftwaffe pushed such deadlines around in the actual BoB, its likely the same would occur with Sealion. Since it took 3-4 weeks to actually assemble the Wehrmacht barge fleet, there should be time for 3-4 weeks of aerial bombardment of the RN fleets & Ports . Precious few operational RN warships SHould be left in the channel by the end of this phase. In fact they probably would have abandoned ‘The Channel’ to the Germans.
Otherwise the Luftwaffe could easily have more than tripled those 'Dunkirk' figures, due to the 3-4 weeks of dive bombing from 300 Stuka on channel targets . That could translate into 225-300 Minesweepers/Armed Trawlers/Destroyers sunk or crippled [gone for months] & another 58 damaged and out of operations for a week. Out of a force of 640 , that’s about ½ of the entire operational ‘anti invasion fleet’ covering the entire UK coast lines. If the RN dash the remaining 280-340 Armed trawlers/Minesweepers/Destroyers to the Channel , then operation "Autumn Journey" could easily have been turned from a faint, into a flanking invasion, since there would be nothing to stop them
If they do try to rush the channel, they still have to cut through the 'English Channel mine barrier' , which could never really be swept, since only 1/3 of the reserved mines would have been deployed in multiple barriers with special designed ‘EMG tidal mines 30-40m apart [Gezeitenmine]’. These would not be easy to sweep since they rose and fell with the tide , and were not exposed by the tidal surges. Further more hundreds of new mines could be deployed every day by minelayer or air drop to re-mined the already swept corridors.
During clear day light hours these EMG tidal mines were easier to detect due to the small buoy they leave , but that would also make those prime areas for Stuka patrols. The Germans erected extensive super gun emplacements along the Channel coast. While they had little chance of hitting anything on a good day, there mere presence would be one more layer for exhausted RN crews to negotiate and those Gun turrets had highly effective Radars allowing Schnellboote & Stuka squadrons to be vectored in to intercept would be minesweepers/blockade runners.
Generally RAF radar didn’t extend sufficiently over the channel to detect the Stuka formations prior to their striking targets even along the English side of the channel. At best RAF fighters would arrive ¼ of an hour after the Stuka left. RAF bomber command was useless at hitting naval shipping , during the war . At that time, coastal command was sinking one ship for every 160 sortie. During dynamo the Germans registered one enemy ship sunk for every 47 sortie flown.
In the week before the expected Sealion invasion, the RAF coastal command bombed the invasion fleet , but only destroyed 65 barges/ships/boats and lightly damaged 160 more [return in a week]. However, after these strikes , the assembled German invasion fleet still counted 1580 converted landing barges [ ½ motorized & the rest towed], 820 Tugs/Leader boats and 100 merchant ships, escorted by 180 MBoot, RBoot & VBoot , which was more than enough to launch the first wave.
In reserve the Germans had another 50 MBoot/RBoot/VBoot plus 44-75 more merchant ships, another 600 converted landing barges and another 200-300 older barges to warehouse supplies. In addition they had another 25 tankers and 75 fuel lighters to effect re supply. At this rate of destruction, it would take the RAF bomber command months to sink the invasion fleet.
At this point in the Sealion plan, each towed barge was also tethered to a motorized barge, for the last run into , and extraction from the beaches, while a tug towed the entire entourage @ ~ 4knts in a 300-400m strung out group. There was supposed to be a ‘leader boat’ for every three tugs. These were command boats with communications & navigating gear to lead the barges independently if needed. Combined, this was enough to lift over ¼ million tons in the first wave alone. That was enough to deploy the first echelon of each infantry division , which were all reinforced to the level of a ‘semi motorized infantry division’ .
Each of 9 divisions could put ashore a divisional Gruppe of roughly 7000 troops, with 600 vehicles/motorcycles plus 1900 bicycles & 340 horses . These were spread over two complete ‘1940 Infantry Regiment’ armed with 47mm PAK instead of 37mm PAK, and reinforced with
a Flak battery [12 x 20mm Flak]
a tank battalion [49 x Pz-II/III/IV & 9 halftracks]
a Nebelwerfer battery [8 MRL]
a Panzer Jaeger company
and a mountain gun battalion [8 x 15cm guns]
plus an entire recon battalion on bicycles.
Each army had an additional Recon battalion; two additional engineering battalions and an additional 10cm Gun battalion to supplement the Armies artillery battalions and flak Regiment.
Each of the approximately 80 barges transporting the Gruppe, had a twin AAMg mounted and manned. In addition most of the barges also had a deck gun platform on which the Gruppe 14 x 75mm infantry guns , 12 x 20mm Flak ,27 x 47mm PAK & 8 x Gebirgskannoe 15cm mountain guns, were all mounted. These guns could be manned during the crossing ,especially in the last run into the beach. Weapons on the gun platforms were primarily for beach fire support and were to be supplemented by the 35 'gun coasters', mostly armed with several light flak & 3 x captured 75mm Guns each. Each tug and “Leader boat” , were armed with a couple of AAMg . So every leader group should have a minimum of ~14 x AAMg as self defense plus. The entire Barge transport Gruppe should be able to amass almost 200 AAMg in self defense.
While the RN anti invasion plan put much faith in near sideswiping of barges at high speed by destroyers or dumping Depth Charges by Minesweepers/Armed Trawlers in similar passes, each barge and/or adjacent barge could very well unload a couple of shell into said passing warship. The accumulated effect could cripple minesweepers and Armed trawlers while damage Destroyers, ensuring they’ll not come back for at least another week. Historically the success of such close clashes were not encouraging, with each Destroyer/Cruiser sortie netting only one enemy barge/boat sunk each time.
Since an average of 5 minesweepers would lead each Barge transport Gruppe , they could each contribute two 4" naval guns and a couple light flak, plus ASW & Minesweeping gear. These would be followed by about 4 auxiliary Gun Coasters each with a couple of light flak and 3 x 3” guns. In addition at least 6-8 VBoot would escort each Gruppe, patrolling the flanks, also equipped with ASW gear, a pair of 88L45 guns and several light flak .About 8 smaller RBoot should provide close in protection with both Minesweeping & ASW gear plus several light flak. Combined these could bring 36 x 3-4”guns to bare on any attacking flotillas , while shore bombardment could climb to 80-90 x 3-4” guns. These escorting groups, should also be covered by at least 80 ship mounted light flak per Barge Gruppe, each putting out a practical ROF of ~100 shells per minute.
Following these barge fleets, would be up to 100 merchants escorted by about two dozen Sperrbrecher mine clearing ships. Its reported all the WW-I Torpedoboot and FBoot were to be used so that’s ~10 more warships available to escort these merchant ships too. Each merchant group should have 11 merchant ships , four with gun decks mounting Army 4” howitzers plus a couple of light flak. Each group would be escorted by ~ 3 Sperrbrecher mine clearing ships plus a Torpedoboot. Each group should be able to amass roughly a dozen 4” guns and 4 torpedos, plus up to 100 Light Flak, each putting out a practical ROF or ~ 100 shells per minute.
During WW-II very effective convoy defensive tactics were established when the convoy conducting defensive turns under cover of smoke screens between the convoy and attacking flotilla. Meanwhile some of the convoy escorts counter attack the attacking enemy flotilla . These escorts tried to distract the attacking enemy flotilla with gunfire and deploying smoke between them and the convoy, long enough for the convoys to escape. Historically such counter attacking escorts came off poorly against enemy Cruiser/Destroyer flotillas, but usually the counter attack of a few of the escorts inflicted serious damage on some of the attacking warships, before they themselves succumbed to fire. Some times however if the counterattacking escort warship was able to launch torpedos, they could make good their own escape after having diverted the enemy attacking flotilla . Since few warships had radar at that time these worked well and should work in the Channel in 1940. Even if they are radar equipped warships, this defensive tactic was shown to work most of the time.
It was planned, the close escorting of the barge groups, was to be done through small coastal RBoot , each equipped with several light flak, ASW gear and smoke dispensing machines, that could generate 1 to 8 hours of smoke, to cover barge fleets, while squadrons of specially equipped planes [ ~ 70] carried numerous smoke bombes to provide instantaneous smoke barrages during specific enemy destroyer sweeps.
Prior to even reaching the convoys these enemy destroyer sweeps would have to navigate mine infested waters dodging submarines in the process and fighting off German destroyer/Schnellboote flotillas of there own. Those German groups counted 3-4 x Destroyer/Torpedoboot flotillas covering the western approaches to the invasion corridor. These included 7 x Z-1934/36 heavy destroyers and 15 x Torpedoboot 1923/24/35, operating in flotillas of up to ½ dozen each, to engage RN flotillas coming through the Western Channel. To bolster this force, a dozen coastal & ½ dozen Atlantic Uboats would patrol the major RN ports and mine barriers . As the fatigue of the RN fleet mounted, these measures could be expected to become more and more effective. Covering the extensive mine barrier approaching the Eastern Channel entrance were two dozen Schnell boot reinforced by another up to ½ dozen coastal Uboats. In addition ‘Scapa Flow’ and the ‘Firth of Forth’ were each to be covered by a flotilla of up to ½ dozen coastal Uboats.
Historically when such flotilla clashed , the Germans sunk or crippled twice as many allied warships as they lost themselves, but rarely more than one warship was sunk on each side per flotilla vs flotilla clash. The only exception out of 18-20 such clashes in the early war years, was the Narvik incident in Norway , which pointed to an opposite result.. So the Germans under no circumstance should fight RN destroyer flotillas lead by a Battleship, in a Fiord/Harbor .
The German Schnellboote flotilla’s covering the eastern mouth of the channel , should also do very well statistically sinking or crippling an enemy warships per day while making good escapes most of the time. Like wise the Uboats should statistically cripple/sink an enemy ship every day also making good an escape most of the time. Over all these German warships could inflict 5-6 enemy sunk/crippled warships per day losing a couple of warships in exchange.
The German warship fleet included 3-4 light cruisers and the heavy cruiser Hipper with the pocket battle cruiser Scheer operational later that month. Both Hipper and Scheer were tasked to sortie ahead of the invasion in order to draw out the RN home fleet. With replenishment at sea , the Scheer could remain operational for at least a month at sea , so it should be deployed weeks before S Day. In contrast the Hipper had only a 2 week endurance with replenishment at sea, so it should sortie a couple of days before S Day to ensure Home fleet cruisers and Battleships are exhausted, when they return to Scapa Flow. The movements of these raiders should be coordinated with 10 long range Uboats surging into the North Atlantic. The aim would be for the surface raiders to hunt down convoys and brake them up while the Uboats move in to pick off the remains, putting a severe strain on the Convoy escort system. If sufficient ,the RN Admiral Forbes demand to strip the ‘Anti Invasion Fleet’ from 90 down to 60 DD/CL would probably have been followed.
The 4 Light Cruisers plus several training ships, escorted by a dozen WW-I/captured Torpedoboot, were to sortie across the North Sea, leading a dozen merchants with thousands of troops in an attempted faint, to fix the RN/RAF east coast forces for days starting with S Day. It was felt this could buy the Channel defenses several days of respite before the Destroyer sweeps come.
As it was ,after just one week of Stuka bombings at Dunkirk in 'Operation Dynamo', at most only 1/3 of the RN destroyers were still operational.... and that was with just 200 Stuka and the beginning effects of ‘fatigue’ from continuous sortie, was just starting to kicking in.
Over a ten day period around ‘Operation Dynamo’, the RN/Allies lost 23 Destroyers crippled or sunk and another 22 damaged and out of operations for at least a week. In addition they lost 42 trawlers/MS/Steamers crippled or sunk and another 16 damage. All from only 200 Stuka. The RAF fought to protect their fleet but lost 177 planes to the Germans loss of only 132 planes.
In the actual Sealion plan , the invasion was to be launched only after 8-10 days of bombing of RN fleets and ports. Given how freely the Luftwaffe pushed such deadlines around in the actual BoB, its likely the same would occur with Sealion. Since it took 3-4 weeks to actually assemble the Wehrmacht barge fleet, there should be time for 3-4 weeks of aerial bombardment of the RN fleets & Ports . Precious few operational RN warships SHould be left in the channel by the end of this phase. In fact they probably would have abandoned ‘The Channel’ to the Germans.
Otherwise the Luftwaffe could easily have more than tripled those 'Dunkirk' figures, due to the 3-4 weeks of dive bombing from 300 Stuka on channel targets . That could translate into 225-300 Minesweepers/Armed Trawlers/Destroyers sunk or crippled [gone for months] & another 58 damaged and out of operations for a week. Out of a force of 640 , that’s about ½ of the entire operational ‘anti invasion fleet’ covering the entire UK coast lines. If the RN dash the remaining 280-340 Armed trawlers/Minesweepers/Destroyers to the Channel , then operation "Autumn Journey" could easily have been turned from a faint, into a flanking invasion, since there would be nothing to stop them
If they do try to rush the channel, they still have to cut through the 'English Channel mine barrier' , which could never really be swept, since only 1/3 of the reserved mines would have been deployed in multiple barriers with special designed ‘EMG tidal mines 30-40m apart [Gezeitenmine]’. These would not be easy to sweep since they rose and fell with the tide , and were not exposed by the tidal surges. Further more hundreds of new mines could be deployed every day by minelayer or air drop to re-mined the already swept corridors.
During clear day light hours these EMG tidal mines were easier to detect due to the small buoy they leave , but that would also make those prime areas for Stuka patrols. The Germans erected extensive super gun emplacements along the Channel coast. While they had little chance of hitting anything on a good day, there mere presence would be one more layer for exhausted RN crews to negotiate and those Gun turrets had highly effective Radars allowing Schnellboote & Stuka squadrons to be vectored in to intercept would be minesweepers/blockade runners.
Generally RAF radar didn’t extend sufficiently over the channel to detect the Stuka formations prior to their striking targets even along the English side of the channel. At best RAF fighters would arrive ¼ of an hour after the Stuka left. RAF bomber command was useless at hitting naval shipping , during the war . At that time, coastal command was sinking one ship for every 160 sortie. During dynamo the Germans registered one enemy ship sunk for every 47 sortie flown.
In the week before the expected Sealion invasion, the RAF coastal command bombed the invasion fleet , but only destroyed 65 barges/ships/boats and lightly damaged 160 more [return in a week]. However, after these strikes , the assembled German invasion fleet still counted 1580 converted landing barges [ ½ motorized & the rest towed], 820 Tugs/Leader boats and 100 merchant ships, escorted by 180 MBoot, RBoot & VBoot , which was more than enough to launch the first wave.
In reserve the Germans had another 50 MBoot/RBoot/VBoot plus 44-75 more merchant ships, another 600 converted landing barges and another 200-300 older barges to warehouse supplies. In addition they had another 25 tankers and 75 fuel lighters to effect re supply. At this rate of destruction, it would take the RAF bomber command months to sink the invasion fleet.
At this point in the Sealion plan, each towed barge was also tethered to a motorized barge, for the last run into , and extraction from the beaches, while a tug towed the entire entourage @ ~ 4knts in a 300-400m strung out group. There was supposed to be a ‘leader boat’ for every three tugs. These were command boats with communications & navigating gear to lead the barges independently if needed. Combined, this was enough to lift over ¼ million tons in the first wave alone. That was enough to deploy the first echelon of each infantry division , which were all reinforced to the level of a ‘semi motorized infantry division’ .
Each of 9 divisions could put ashore a divisional Gruppe of roughly 7000 troops, with 600 vehicles/motorcycles plus 1900 bicycles & 340 horses . These were spread over two complete ‘1940 Infantry Regiment’ armed with 47mm PAK instead of 37mm PAK, and reinforced with
a Flak battery [12 x 20mm Flak]
a tank battalion [49 x Pz-II/III/IV & 9 halftracks]
a Nebelwerfer battery [8 MRL]
a Panzer Jaeger company
and a mountain gun battalion [8 x 15cm guns]
plus an entire recon battalion on bicycles.
Each army had an additional Recon battalion; two additional engineering battalions and an additional 10cm Gun battalion to supplement the Armies artillery battalions and flak Regiment.
Each of the approximately 80 barges transporting the Gruppe, had a twin AAMg mounted and manned. In addition most of the barges also had a deck gun platform on which the Gruppe 14 x 75mm infantry guns , 12 x 20mm Flak ,27 x 47mm PAK & 8 x Gebirgskannoe 15cm mountain guns, were all mounted. These guns could be manned during the crossing ,especially in the last run into the beach. Weapons on the gun platforms were primarily for beach fire support and were to be supplemented by the 35 'gun coasters', mostly armed with several light flak & 3 x captured 75mm Guns each. Each tug and “Leader boat” , were armed with a couple of AAMg . So every leader group should have a minimum of ~14 x AAMg as self defense plus. The entire Barge transport Gruppe should be able to amass almost 200 AAMg in self defense.
While the RN anti invasion plan put much faith in near sideswiping of barges at high speed by destroyers or dumping Depth Charges by Minesweepers/Armed Trawlers in similar passes, each barge and/or adjacent barge could very well unload a couple of shell into said passing warship. The accumulated effect could cripple minesweepers and Armed trawlers while damage Destroyers, ensuring they’ll not come back for at least another week. Historically the success of such close clashes were not encouraging, with each Destroyer/Cruiser sortie netting only one enemy barge/boat sunk each time.
Since an average of 5 minesweepers would lead each Barge transport Gruppe , they could each contribute two 4" naval guns and a couple light flak, plus ASW & Minesweeping gear. These would be followed by about 4 auxiliary Gun Coasters each with a couple of light flak and 3 x 3” guns. In addition at least 6-8 VBoot would escort each Gruppe, patrolling the flanks, also equipped with ASW gear, a pair of 88L45 guns and several light flak .About 8 smaller RBoot should provide close in protection with both Minesweeping & ASW gear plus several light flak. Combined these could bring 36 x 3-4”guns to bare on any attacking flotillas , while shore bombardment could climb to 80-90 x 3-4” guns. These escorting groups, should also be covered by at least 80 ship mounted light flak per Barge Gruppe, each putting out a practical ROF of ~100 shells per minute.
Following these barge fleets, would be up to 100 merchants escorted by about two dozen Sperrbrecher mine clearing ships. Its reported all the WW-I Torpedoboot and FBoot were to be used so that’s ~10 more warships available to escort these merchant ships too. Each merchant group should have 11 merchant ships , four with gun decks mounting Army 4” howitzers plus a couple of light flak. Each group would be escorted by ~ 3 Sperrbrecher mine clearing ships plus a Torpedoboot. Each group should be able to amass roughly a dozen 4” guns and 4 torpedos, plus up to 100 Light Flak, each putting out a practical ROF or ~ 100 shells per minute.
During WW-II very effective convoy defensive tactics were established when the convoy conducting defensive turns under cover of smoke screens between the convoy and attacking flotilla. Meanwhile some of the convoy escorts counter attack the attacking enemy flotilla . These escorts tried to distract the attacking enemy flotilla with gunfire and deploying smoke between them and the convoy, long enough for the convoys to escape. Historically such counter attacking escorts came off poorly against enemy Cruiser/Destroyer flotillas, but usually the counter attack of a few of the escorts inflicted serious damage on some of the attacking warships, before they themselves succumbed to fire. Some times however if the counterattacking escort warship was able to launch torpedos, they could make good their own escape after having diverted the enemy attacking flotilla . Since few warships had radar at that time these worked well and should work in the Channel in 1940. Even if they are radar equipped warships, this defensive tactic was shown to work most of the time.
It was planned, the close escorting of the barge groups, was to be done through small coastal RBoot , each equipped with several light flak, ASW gear and smoke dispensing machines, that could generate 1 to 8 hours of smoke, to cover barge fleets, while squadrons of specially equipped planes [ ~ 70] carried numerous smoke bombes to provide instantaneous smoke barrages during specific enemy destroyer sweeps.
Prior to even reaching the convoys these enemy destroyer sweeps would have to navigate mine infested waters dodging submarines in the process and fighting off German destroyer/Schnellboote flotillas of there own. Those German groups counted 3-4 x Destroyer/Torpedoboot flotillas covering the western approaches to the invasion corridor. These included 7 x Z-1934/36 heavy destroyers and 15 x Torpedoboot 1923/24/35, operating in flotillas of up to ½ dozen each, to engage RN flotillas coming through the Western Channel. To bolster this force, a dozen coastal & ½ dozen Atlantic Uboats would patrol the major RN ports and mine barriers . As the fatigue of the RN fleet mounted, these measures could be expected to become more and more effective. Covering the extensive mine barrier approaching the Eastern Channel entrance were two dozen Schnell boot reinforced by another up to ½ dozen coastal Uboats. In addition ‘Scapa Flow’ and the ‘Firth of Forth’ were each to be covered by a flotilla of up to ½ dozen coastal Uboats.
Historically when such flotilla clashed , the Germans sunk or crippled twice as many allied warships as they lost themselves, but rarely more than one warship was sunk on each side per flotilla vs flotilla clash. The only exception out of 18-20 such clashes in the early war years, was the Narvik incident in Norway , which pointed to an opposite result.. So the Germans under no circumstance should fight RN destroyer flotillas lead by a Battleship, in a Fiord/Harbor .
The German Schnellboote flotilla’s covering the eastern mouth of the channel , should also do very well statistically sinking or crippling an enemy warships per day while making good escapes most of the time. Like wise the Uboats should statistically cripple/sink an enemy ship every day also making good an escape most of the time. Over all these German warships could inflict 5-6 enemy sunk/crippled warships per day losing a couple of warships in exchange.
The German warship fleet included 3-4 light cruisers and the heavy cruiser Hipper with the pocket battle cruiser Scheer operational later that month. Both Hipper and Scheer were tasked to sortie ahead of the invasion in order to draw out the RN home fleet. With replenishment at sea , the Scheer could remain operational for at least a month at sea , so it should be deployed weeks before S Day. In contrast the Hipper had only a 2 week endurance with replenishment at sea, so it should sortie a couple of days before S Day to ensure Home fleet cruisers and Battleships are exhausted, when they return to Scapa Flow. The movements of these raiders should be coordinated with 10 long range Uboats surging into the North Atlantic. The aim would be for the surface raiders to hunt down convoys and brake them up while the Uboats move in to pick off the remains, putting a severe strain on the Convoy escort system. If sufficient ,the RN Admiral Forbes demand to strip the ‘Anti Invasion Fleet’ from 90 down to 60 DD/CL would probably have been followed.
The 4 Light Cruisers plus several training ships, escorted by a dozen WW-I/captured Torpedoboot, were to sortie across the North Sea, leading a dozen merchants with thousands of troops in an attempted faint, to fix the RN/RAF east coast forces for days starting with S Day. It was felt this could buy the Channel defenses several days of respite before the Destroyer sweeps come.