Overview of proposed operations from sea lion?

[flakbait]

Believe that Churchill and the Government and Royal Navy were to go to Canada...

[harry6116]

thanks for that info.

Michael

[flakbait]

Does anyone have information on RAF attacks on the approx. 70 assembled ferry ships which would obviously carry the bulk of the armored vehicles? Of the entire assembled landing flotilla would have to imagine they would be seen as THE most important targets... Landing infantry is 1 thing; getting armored vehicles ashore successfully onto a hostile beach is a much harder proposition. Landing WITHOUT armored support would be almost suicidal, and BOTH sides obviously realized this. NO heavy ferries, NO credible threat of a landing...

[phylo_roadking]

Does anyone have information on RAF attacks on the approx. 70 assembled ferry ships which would obviously carry the bulk of the armored vehicles? Of the entire assembled landing flotilla would have to imagine they would be seen as THE most important targets... Landing infantry is 1 thing; getting armored vehicles ashore successfully onto a hostile beach is a much harder proposition. Landing WITHOUT armored support would be almost suicidal, and BOTH sides obviously realized this. NO heavy ferries, NO credible threat of a landing...

...remembering of course the 250 or so snorkelling panzers...!

Weather and moon permitted 5-6 really heavy "bargebusting" night,s starting in the first week of September. There's a long Sealion thread (now closed) elsewhere on the board that contains sortie nuumbers for RAF aircraft on those nights. On the biggest, ALL the RAF's bomber types, right down to Fairey Battles, were sortied. In total the RAF sunk some 15-17% of assembled invasion shipping...

Note the word "assembled" - the Germans kept their invasion shipping distributed in penny packets up and down the coast of France and the Low Countries until then; only in the very last days of August did they start assembling...clustering...it. For obvious reasons.

[Maxschnauzer]

Phylo, A little off topic but related to your posts: The arrival of the first American troops in the European Theater; Belfast, January 26,1942:
http://www.belfasttelegraph.co.uk/life/ ... 00542.html

This has been discussed before on AHF Actually - they weren't the first! Two companies of U.S. Marines had been shipped quickly to Londonderry and the new USN convoy escort base being built there on Derry's "Waterside" in December 1941! They were accomodated in a Nissen hutted camp quickly erected in the grounds of a large stately home there beside the USN base, now a hotel.

I stand corrected! (Though I'm struggling to find any documentation on when exactly the Marines arrived). This brief timeline indicates that as early as the summer of 1941 civilian techs and the Navy Civil Engineer Corps (the Seabees parent command and my old alma mater ), were constructing the infrastructure to accommodate these troops at Ardmore while the Marines stayed in temporary housing at the Beech Hill Country Estate:

June 30, 1941 — 362 civilian technicians arrive in Derry.

August 1, 1941 — US Navy Civil Engineering [sic] Corps begin construction work.

December 7, 1941 — Pearl Harbor attacks.

December ?, 1941 -- Marines arrive (my edit)

January 26, 1942 — 4,508 soldiers from 34th Infantry Regiment docked in Belfast.

February 5, 1942 — Naval Operating Base in Derry formally commissioned.

From http://www.examiner.com/article/secret- ... nd-release

Other info on this at:
http://www.belfasttelegraph.co.uk/news/ ... 76508.html

[flakbait]

Am not aware of how deep a snorkeling panzer could ford, but am certain the shortest distance between occupied France and England at that time had depths of over 60 feet of water, sir. (Several submerged U boats successfully transited the Straits of Dover early in the war) plus the bottom isn`t even, and there are currents. Am not certain a compass would work very well inside a steel tank hull, plus water pressure at 60` might be a problem...destroying even part of those vehicle ferries means the invasion will have few (if any) panzers supporting it at least until a functioning harbor is secured.

[Maxschnauzer]

I believe the maximum operational depth of the Tauchpanzer was 15 meters which isn't bad as long as they were able to keep moving so as not to get stuck in the seabed and their hoses stayed afloat and unfouled. The only way I could see them being viable in Sea Lion would have been to deploy them from barges or landing craft at a reasonable depth which in itself was a difficult operation in any case. They did see some use in river crossings during Barbarossa, however.

[flakbait]

Was impressed to see the German version of a "Mulberry" type structure previously while reading the older thread, as well as the fording kit. For the sake of argument the "Mulberry" was not available in time in great enough numbers and while the while the fording tank kits DID exist am not certain how well they would have worked just driving or even lowering a tank over the side of a ship. There is also the 20 minute limit to consider... it IS possible but how many ships carrying them will survive long enough to launch them; too, would imagine the ships have to be close to motionless while launching them...probably well within the defenders` longer ranged weapons. No matter how you look at it, the obvious answer at this moment of the war is to capture an INTACT harbor...which the Brits were NOT going to allow.

[phylo_roadking]

I stand corrected! (Though I'm struggling to find any documentation on when exactly the Marines arrived). This brief timeline indicates that as early as the summer of 1941 civilian techs and the Navy Civil Engineer Corps (the Seabees parent command and my old alma mater ), were constructing the infrastructure to accommodate these troops at Ardmore while the Marines stayed in temporary housing at the Beech Hill Country Estate:

You may have just gone looking in the worng direction The "in" is the Beechill hotel!

They occupied the new hutted camp in the grounds of Beechill House on the 5th of February 1942 on the day the new base was commissioned, but were there for some time before that.

THIS is the new page on the Beechill House site regarding the marines in Derry....http://www.beech-hill.com/marines-arrive.aspx but it has changed somewhat in the intervening years! The original page was 3-4 times as long, contained a LOT more detail, and had a lot more pics! And used to have a whole page on veterans' memories of the posting that seems to have been edited off

Note that the base was "established" in February 1942; but as you know, it was there for some time BEFORE that I suppose I'll have to drop into the new museum in Derry next time I'm up there.

[phylo_roadking]

Was impressed to see the German version of a "Mulberry" type structure previously while reading the older thread, as well as the fording kit. For the sake of argument the "Mulberry" was not available in time in great enough numbers

It wasn't; not until 1941 IIRC....along with the various classes of MFPs, the Messerschmitt Gigant glider etc. etc...

and while the while the fording tank kits DID exist am not certain how well they would have worked just driving or even lowering a tank over the side of a ship. There is also the 20 minute limit to consider... it IS possible but how many ships carrying them will survive long enough to launch them; too, would imagine the ships have to be close to motionless while launching them...probably well within the defenders` longer ranged weapons. No matter how you look at it, the obvious answer at this moment of the war is to capture an INTACT harbor...which the Brits were NOT going to allow.

The first thing to remember is that the defenders at the "Emergency Batteries" were restricted by orders to a 6,000 yard range due to the low levels of available ammunition - the idea being that the closer they let the landing forces get, the better their accuracy for their allotment of ordnance.

Second is - the Germans always planned to halt, anchor and embark onto barges etc. from cargo ships off the coast I.E. only a certain number of barges would ever be crossing the Channel fully loaded.

Thirdly - there was only a limited number of "Emergency Batteries" along the coast; the chain of two-gun batteries was completed ....installations nearly doubled...into 1941, but there were large stretches of coast in 1940 covered by only one or two-two-gun batteries.

Am not aware of how deep a snorkeling panzer could ford, but am certain the shortest distance between occupied France and England at that time had depths of over 60 feet of water, sir.

I believe the maximum operational depth of the Tauchpanzer was 15 meters which isn't bad as long as they were able to keep moving so as not to get stuck in the seabed and their hoses stayed afloat and unfouled. The only way I could see them being viable in Sea Lion would have been to deploy them from barges or landing craft at a reasonable depth which in itself was a difficult operation in any case. They did see some use in river crossings during Barbarossa, however.

They were to be winched over the side of anchored cargo ships off the coast and make their way in. At the planned distance from the coast, and in the locations planned...they were going to be crawling along on a firm sand/mud bottom free from rocks or obstructions. At low tide these slowly-sloping beaches stretch well over a mile out to sea...!

[LWD]

... Second is - the Germans always planned to halt, anchor and embark onto barges etc. from cargo ships off the coast I.E. only a certain number of barges would ever be crossing the Channel fully loaded. ...

My impression is that most if not all the barges were to make the crossing loaded. However they did intend on recovering some from the beaches and using them along with small craft to unload the cargo ships at least until they could sieze a port. Of course that impression could be wrong.

[phylo_roadking]

My impression is that most if not all the barges were to make the crossing loaded.

There does seem to be two broad impressions about - but its clear that the cargo ships were to stop off the coast disembarking something into a percentage of the barges Given all the issues with a low freeboard when fully loaded - sometimes only 18 inches above the water - it makes sense for barges to make their way across PARTLY loaded, possibly taking on troops etc. offshore for the final run in. Certainly after the initial landings the barges were to carry out the same broad function as DUKWs etc. on D-Da and after - taxiing men and materiel ashore.

[LWD]

Again my impression is that most of the barges, in particular those with troops, would have been fully loaded in the sense of all the deck/hold space was used but no where near all the displacement was used. I'm pretty sure the ones with guns were suppose to be run onto the beach and provide fire support until they were out of ammo, destroyed, or the battle moved out of their range. Likewise the one practice run I read about didn't bode well for getting many off the beach but that's still my impression of what the German plan was. They did have some ships boats that they could have used to ferry people ashore but if you are talking unloading artillery, ammo, and such I think they were relying on capturing a port intact.

[phylo_roadking]

Again my impression is that most of the barges, in particular those with troops, would have been fully loaded in the sense of all the deck/hold space was used but no where near all the displacement was used.

Cubic displacement, no; because the weight displacement had been hugely used up filling the bilges with concrete and railway rails etc. for ballast and strengthening to carry vehicles.

I'm pretty sure the ones with guns were suppose to be run onto the beach and provide fire support until they were out of ammo, destroyed, or the battle moved out of their range.

ALL the unmotored barges were to be run ashore; There were three types of "ramp"....two of which required actually getting out and assembling them once on the beach. Only a third of the barges were fitted with A-frames and ramps that they could lower or winch out from the barge onto the beach.

They did have some ships boats that they could have used to ferry people ashore but if you are talking unloading artillery, ammo, and such I think they were relying on capturing a port intact.

They also had the several hundred auxiliary armed fishing boats/trawlers etc., many of which...as well as escorts...were to be used in addition to the motored barges and tugs, for pulling barges across the Channel. And several hundred...thousand?..."motor yachts" that were to be used en masse at several locations - these would have been available after the first invasion wave to use as "water taxis".

A port would certainly have been essential for the eventual breakout from the bridgehead and on-land campaign...due to the sheer tonnage of materiel needing to be transported across the Channel. 9,000 tons of horse fodder a week, for example...!

[Maxschnauzer]

They occupied the new hutted camp in the grounds of Beechill House on the 5th of February 1942 on the day the new base was commissioned, but were there for some time before that.

That makes perfect sense, though I'm still looking for reference to any Marines present before early '42 Do you think they might have been an advance security detail transferred to Derry from London?

I'm sure the whole story is documented in the Beech Hill archives. I'll try to contact The Beech Hill US Navy and Marine Corps Association, via http://btportraitofacity.com/?page_id=1049. If you can get over to the museum someday it would be great. Derry is a bit of a trek for me these days.