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Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Mon Nov 02, 2015 4:51 pm
by Francis Marliere
Paul L wrote:Germans already had sufficient shipping to launch a cross channel invasion by mid 1941. With 100 MFP & 240 Seibel ferries PLUS 1700 converted river barges -most motorized...and 150 merchant ships
Gentlemen,

In my humble opinion, the chances that the German succeed to land on the British coast are very remote. Being a Frenchman who lives in northern France, I know that the Channel, while narrow, is not easy to navigate.
Working on the field of inland navigation, I also know that the 'converted barges' of the time were mostly small, unmotorized wooden ships with very low freeboard, hence unable to sail in open sea or take any amount of damage.
I fear that any attempt to cross the Channel with barges had great chances to end in desaster for the Germans, even with no intervention from the RAF or RN.

Best regards,

Francis Marliere

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Mon Nov 02, 2015 7:00 pm
by RF
I think the conclusions here are a fair assessment, assuming that by the autumn of 1941 the Germans had not properly planned an invasion having developed and put into service specialist landing craft. Also without massive degradation of the British defences from the air and by seaborne blockade an invasion is a non-starter.

The D Day landings in 1944 were a complete success, even allowing for the hold up on Omaha beach, with Allied forces crossing a very wide stretch of the Channel in poor weather.

Properly planned and executed Sea Lion was a realistic proposition - even in the face of substantial surface ship opposition. That still does not guarantee success but is a dire threat at least.

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Tue Nov 03, 2015 6:39 am
by alecsandros
Francis Marliere wrote:
Paul L wrote:Germans already had sufficient shipping to launch a cross channel invasion by mid 1941. With 100 MFP & 240 Seibel ferries PLUS 1700 converted river barges -most motorized...and 150 merchant ships
Gentlemen,

In my humble opinion, the chances that the German succeed to land on the British coast are very remote. Being a Frenchman who lives in northern France, I know that the Channel, while narrow, is not easy to navigate.
Working on the field of inland navigation, I also know that the 'converted barges' of the time were mostly small, unmotorized wooden ships with very low freeboard, hence unable to sail in open sea or take any amount of damage.
I fear that any attempt to cross the Channel with barges had great chances to end in desaster for the Germans, even with no intervention from the RAF or RN.

Best regards,

Francis Marliere
... Which is why a late 1941early 1942 Sea Lion would have been prefered: to have time to build sufficient specialised landing craft, such as

https://en.wikipedia.org/wiki/Marinef%C3%A4hrprahm

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Tue Nov 03, 2015 7:10 am
by Tom17
What part of the English coast would the German sea based forces concentrate on?
A quick capture of a port would be essential.

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Tue Nov 03, 2015 9:54 am
by Francis Marliere
alecsandros wrote:... Which is why a late 1941early 1942 Sea Lion would have been prefered: to have time to build sufficient specialised landing craft, such as

https://en.wikipedia.org/wiki/Marinef%C3%A4hrprahm
Well, if the German build hundreds of these landing crafts for an invasion of Great-Britain, I assume that the British would build the kind of things to oppose them (such as MTB and fighter bombers).
Anyway, the RN still has a hudge superiority over DKM and I cannot see how the German could prevent British warships to sink the invasion fleet.

Best regards,

Francis Marliere

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Tue Nov 03, 2015 10:40 am
by alecsandros
Francis Marliere wrote:I assume that the British would build the kind of things to oppose them (such as MTB and fighter bombers).
Anyway, the RN still has a hudge superiority over DKM and I cannot see how the German could prevent British warships to sink the invasion fleet.

Best regards,

Francis Marliere
... A simple way to cover the invasion force would be to send it by night, with first landings at first light.

Various decoys, false landings, false convoys, radar jamming, etc, would distort the British perception of the action, and dillute the strength of the naval attack.

Probably all operational Uboats and Torpedo boats would be redeployed in the Channell, and there were quite a few in late 1941... This along with the surface force which would have at the very least Tirpitz, Scharhorst, Gneisenau, Hipper, Lutzow, Prinz Eugen, Scheer, and 18 destroyers.

I would also expect massive heavy artillery planted on the shore line (280mm and more), with radar support, for covering fire.

===

A critical aspect would also be exactly how many units could Britain concentrate to fend off an invasion. Protecting the shipping lanes and keeping Mediteranean were essential, and the need to provide some forces in the far east was important also.
Some ships would be in repair/refits, and thus only a fraction of the total assets of the Fleet would be available, on a moment's notice, to sortie and engage the enemy.

(historical Dec 1941 for example has Prince of Wales, Repulse (assuming they wouldn't be sent to Singapore), KGV, Rodney, Duke of York (shakedown), Renown, Revenge, Malaya, Royal Sovereign were the available capital ships . Carriers: Eagle, Victorious. Considerable number of smaller ships (at least 30 cruisers and 100 DDs operational) )

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Wed Nov 04, 2015 7:11 am
by Steve Crandell
alecsandros wrote: A critical aspect would also be exactly how many units could Britain concentrate to fend off an invasion. Protecting the shipping lanes and keeping Mediteranean were essential, and the need to provide some forces in the far east was important also.
Some ships would be in repair/refits, and thus only a fraction of the total assets of the Fleet would be available, on a moment's notice, to sortie and engage the enemy.

(historical Dec 1941 for example has Prince of Wales, Repulse (assuming they wouldn't be sent to Singapore), KGV, Rodney, Duke of York (shakedown), Renown, Revenge, Malaya, Royal Sovereign were the available capital ships . Carriers: Eagle, Victorious. Considerable number of smaller ships (at least 30 cruisers and 100 DDs operational) )
This problem would affect the Germans as well. All of their ships were seldom available at any given time.

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Wed Nov 04, 2015 7:57 am
by alecsandros
Steve Crandell wrote:
alecsandros wrote: A critical aspect would also be exactly how many units could Britain concentrate to fend off an invasion. Protecting the shipping lanes and keeping Mediteranean were essential, and the need to provide some forces in the far east was important also.
Some ships would be in repair/refits, and thus only a fraction of the total assets of the Fleet would be available, on a moment's notice, to sortie and engage the enemy.

(historical Dec 1941 for example has Prince of Wales, Repulse (assuming they wouldn't be sent to Singapore), KGV, Rodney, Duke of York (shakedown), Renown, Revenge, Malaya, Royal Sovereign were the available capital ships . Carriers: Eagle, Victorious. Considerable number of smaller ships (at least 30 cruisers and 100 DDs operational) )
This problem would affect the Germans as well. All of their ships were seldom available at any given time.
Of course;
what I posted was a historical operational strength of KGM in Dec 1941. (1 BB, 2 BC, 4 large CAs, 18 DDs). They could also use about 40 Uboats and 30 torpedo boats (operational at the time).

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Wed Nov 04, 2015 8:24 pm
by Paul L
Francis Marliere wrote:
alecsandros wrote:... Which is why a late 1941early 1942 Sea Lion would have been prefered: to have time to build sufficient specialised landing craft, such as

https://en.wikipedia.org/wiki/Marinef%C3%A4hrprahm
Well, if the German build hundreds of these landing crafts for an invasion of Great-Britain, I assume that the British would build the kind of things to oppose them (such as MTB and fighter bombers).
Anyway, the RN still has a hudge superiority over DKM and I cannot see how the German could prevent British warships to sink the invasion fleet.

Best regards,

Francis Marliere
In peace time building patterns are set in cycles of so many years. Last one for the RN was 1937 with next update in 1940[?] Any ship built in 1941 would have to be ordered in 1940 at the latest, years earlier if its a large ship. Point is did the HMG/RN know for sure about the MFP and Seibel ferries in 1940. They did towards the end of the 1940 as a result of mad German scramble for Sea Lion, but if their is no Sea lion in 1940 there is no reason to tip them off. Ultra didn't penetrate KM until a lot later in the war.

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Thu Nov 05, 2015 8:29 am
by alecsandros
Paul L wrote: In peace time building patterns are set in cycles of so many years. Last one for the RN was 1937 with next update in 1940[?] Any ship built in 1941 would have to be ordered in 1940 at the latest, years earlier if its a large ship. Point is did the HMG/RN know for sure about the MFP and Seibel ferries in 1940. They did towards the end of the 1940 as a result of mad German scramble for Sea Lion, but if their is no Sea lion in 1940 there is no reason to tip them off. Ultra didn't penetrate KM until a lot later in the war.
... The British had enough resources to stop ferries and MTBs. It would be a matter of available information... In 1940, the RAF did bomb German sloops which were expected to be massing for crossing the Channell.

IMHO , the Germans , lacking Barbarossa, would also possess sufficient resources to organise a realistic invasion somewhere in late 1941.

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Thu Nov 05, 2015 9:07 pm
by Paul L
alecsandros wrote:
Paul L wrote: In peace time building patterns are set in cycles of so many years. Last one for the RN was 1937 with next update in 1940[?] Any ship built in 1941 would have to be ordered in 1940 at the latest, years earlier if its a large ship. Point is did the HMG/RN know for sure about the MFP and Seibel ferries in 1940. They did towards the end of the 1940 as a result of mad German scramble for Sea Lion, but if their is no Sea lion in 1940 there is no reason to tip them off. Ultra didn't penetrate KM until a lot later in the war.
... The British had enough resources to stop ferries and MTBs. It would be a matter of available information... In 1940, the RAF did bomb German sloops which were expected to be massing for crossing the Channell.

IMHO , the Germans , lacking Barbarossa, would also possess sufficient resources to organise a realistic invasion somewhere in late 1941.
The bombing of the barges was probably a warning to the British that they had no effective defence against invasion. While 10% of the assembled barges were reported destroyed - most were returned to service in side of a week, leaving the RN to repeal any invasion. But any direct action by the RN would cost them dearly in escorts and destroyers and odds are they would not destroy enough of the armada to prevent successive landings and replenishment.

Given stubborn German resistance they would survive long enough on the beach to break out in sufficient quantities to spread panic through out the British Rear.

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Fri Nov 06, 2015 7:52 am
by alecsandros
Paul L wrote:
alecsandros wrote:
Paul L wrote: In peace time building patterns are set in cycles of so many years. Last one for the RN was 1937 with next update in 1940[?] Any ship built in 1941 would have to be ordered in 1940 at the latest, years earlier if its a large ship. Point is did the HMG/RN know for sure about the MFP and Seibel ferries in 1940. They did towards the end of the 1940 as a result of mad German scramble for Sea Lion, but if their is no Sea lion in 1940 there is no reason to tip them off. Ultra didn't penetrate KM until a lot later in the war.
... The British had enough resources to stop ferries and MTBs. It would be a matter of available information... In 1940, the RAF did bomb German sloops which were expected to be massing for crossing the Channell.

IMHO , the Germans , lacking Barbarossa, would also possess sufficient resources to organise a realistic invasion somewhere in late 1941.
The bombing of the barges was probably a warning to the British that they had no effective defence against invasion. While 10% of the assembled barges were reported destroyed - most were returned to service in side of a week, leaving the RN to repeal any invasion. But any direct action by the RN would cost them dearly in escorts and destroyers and odds are they would not destroy enough of the armada to prevent successive landings and replenishment.

Given stubborn German resistance they would survive long enough on the beach to break out in sufficient quantities to spread panic through out the British Rear.
I suppose it could develop like that. With all German resources concentrated for an invasion, it would be difficult (but not imopssible) for the British to defend themselves.

It would all depend on the concentration and intelligence both sides would manage to obtain.

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Fri Nov 06, 2015 9:03 am
by RF
alecsandros wrote: I suppose it could develop like that. With all German resources concentrated for an invasion, it would be difficult (but not imopssible) for the British to defend themselves.

It would all depend on the concentration and intelligence both sides would manage to obtain.
It would also be influenced by US reaction. Remember that by this time Lend-Lease was well under way. With Britain facing invasion and the USSR still a hostile neutral, the US would beef up its help for Britain, with U-boats attacking American shipping helping Roosevelt to justify it to the home population.

Extending this line of reasoning further, you could consider Japanese reactions to an imminent invasion of Britain, viz their position with the USA. The Japanese could advance their plans for launching hostilities against the US and Britain by two months - throwing Britain into a Far East war at the same time as facing invasion.

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Fri Nov 06, 2015 11:07 am
by alecsandros
RF wrote:
alecsandros wrote: I suppose it could develop like that. With all German resources concentrated for an invasion, it would be difficult (but not imopssible) for the British to defend themselves.

It would all depend on the concentration and intelligence both sides would manage to obtain.
It would also be influenced by US reaction. Remember that by this time Lend-Lease was well under way. With Britain facing invasion and the USSR still a hostile neutral, the US would beef up its help for Britain, with U-boats attacking American shipping helping Roosevelt to justify it to the home population.

Extending this line of reasoning further, you could consider Japanese reactions to an imminent invasion of Britain, viz their position with the USA. The Japanese could advance their plans for launching hostilities against the US and Britain by two months - throwing Britain into a Far East war at the same time as facing invasion.
Clearly so.
This gives intelligence a stronger role. If German plans are taken seriously early enough, then the British and Americans can plan accordingly and redeploy considerable forces to homeland, even sacrificing all else.

If on the other hand the Germans manage to make the Allies believe that the threat is small and / or the threat will come somewhere in 1943-44, then things can be rather dire for the British isles...

Re: No Barbarossa AND Operation Sea Lion Oct 1941

Posted: Fri Nov 06, 2015 8:04 pm
by Paul L
If it boils down to Intel the Germans had the edge until after Norway 1940 and the allies certainly had the edge from 1942 LW/Heer and 1943 KM on...in-between could be a toss up. Reading LW/HEER traffic was good source, but KM was difficult source.

I cant see the Allies not being aware of basic of any plan from 1941 on.