Sealion compared to historical amphib assaults?

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Gooner1
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Re: Sealion compared to historical amphib assaults?

Post by Gooner1 » 10 May 2018 16:41

Sheldrake wrote:The trouble with both of these reports is that neither led to action. In the best British traditions we commissioned a report then found jolly good reasons for doing something else.
Yes, that's sometimes just as well though. If the Government of the day had followed the recommendations of the Defence Requirements sub-Committee reports, it is probable that the British Army in France in 1940 would have been large enough to help make French defeat unlikely. Then look at the trouble that would have caused!

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Re: Sealion compared to historical amphib assaults?

Post by MarkN » 11 May 2018 17:23

Sheldrake wrote:The trouble with both of these reports is that neither led to action.
Quite so!

Took about 3 years to shake of small-war habits during a big-war before they became effective. Then as soon as they'd learned how to do big-war effectively, they promptly forget it all again as they returned to the far more familiar peace-time small-war colonial policing habit.
Sheldrake wrote:In the best British traditions we commissioned a report then found jolly good reasons for doing something else.
Never ending story....

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Re: Sealion compared to historical amphib assaults?

Post by hifigadget » 06 Oct 2018 10:02

One of the favorite topics of alternative history (and one of the scenarios endlessly replayed in war games such as Axis & Allies and 3rd Reich) is what if Germany had attempted Operation Sea Lion. Assuming a Luftwaffe victory over the Royal Air Force in the Battle of Britain was Sea Lion feasible in other respects?
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Kingfish
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Re: Sealion compared to historical amphib assaults?

Post by Kingfish » 07 Oct 2018 01:08

hifigadget wrote:
06 Oct 2018 10:02
Assuming a Luftwaffe victory over the Royal Air Force in the Battle of Britain was Sea Lion feasible in other respects?
A favorable air condition, if not outright air superiority, was a prerequisite for Sealion, but it was by no means the guarantee of a successful invasion. The fact is the German army lacked the means to transport and supply an army the size needed to conquer the British on their home soil.

Even with a dominant Luftwaffe overhead the attrition rate among the transports and barges would have been very high, and there was little else to replace them.
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Re: Sealion compared to historical amphib assaults?

Post by sitalkes » 18 Oct 2018 01:01

Kingfish wrote:
07 Oct 2018 01:08

The fact is the German army lacked the means to transport and supply an army the size needed to conquer the British on their home soil.

Even with a dominant Luftwaffe overhead the attrition rate among the transports and barges would have been very high, and there was little else to replace them.
The first wave was to land with rations for two weeks and a significant portion of German logistics involved scrounging/looting/buying from the locals. Even though measures were taken to reduce such supplies in the invasion area, there would have been some. It would have been close to harvest time in a country that had not been invaded for supposedly 1000 years. The Nazis had experience looking for it in a country that had no experience hiding it, including fodder for the horses. They had already mapped out where they could put water wells and find other water supplies. Getting enough ammunition across would have been the main problem.

The total number of vessels in the invasion fleet was over 3,000, though not all would be used at once. The Achilles heel of the transport fleet was the 400 or so tugs; once they were gone then it would be all over. However, there were plenty of barges and a single barge had the capacity to supply two divisions for a day (based on weight, obviously a great variety of supplies would not fit as easily as a boatload of coal though). There were at least 150 ships of various sizes, the largest being trans-Atlantic liners (the ones to be used in the Channel were converted to hospital ships). The airborne troops at least could be supplied by air once sufficient airfields had been captured. There was plenty of space to unload cargoes over the beaches, as was done in Normandy until September 1944 without the use of a Mulberry in the American sector. They did have the space/capacity to unload cargoes over the beaches to supply more than the whole German invasion force but that of course would only have been on good weather days, of which there would have been fewer as the season advanced towards winter. On bad weather days, the initial invasion area could only support the first wave of invaders via local scrounging, and through the ports. The second and subsequent waves would have to capture other ports (like Portsmouth, Southampton, and Chatham) and repair the ports they had very quickly to be supplied during storms.

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Re: Sealion compared to historical amphib assaults?

Post by Kingfish » 19 Oct 2018 23:14

Forget about the first wave, which had it's own unique problems to deal with, I'm talking about the second and third waves, all of which had to be brought over if Sealion were to have any chance of success. Each additional wave increases the logistical requirements two fold, but the ability to keep up with that demand does not increase in stride. If anything it plummets significantly before, during and after the initial landings.

BTW, I can't think of a better example of an invasion that can't support itself than one that relies of scrounging by the invasion troops.
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Re: Sealion compared to historical amphib assaults?

Post by Carl Schwamberger » 19 Oct 2018 23:59

Kingfish wrote:
19 Oct 2018 23:14
...

BTW, I can't think of a better example of an invasion that can't support itself than one that relies of scrounging by the invasion troops.
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Re: Sealion compared to historical amphib assaults?

Post by gracie4241 » 23 Apr 2019 21:26

I think when you're definition of "Amphibious Assault"includes river barges in the fall in the Channel, as they say "Houston we've got a (big) problem"

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sitalkes
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Re: Sealion compared to historical amphib assaults?

Post by sitalkes » 24 Apr 2019 00:10

Not all of them were river barges, many were coastal barges. There are five videos on YouTube of these barges crossing the channel in September/October (on tourist trips) without problems. The crossing would not have been made in a storm. On a recent trip to the proposed invasion beaches during September I saw perfect invasion weather, when there weren't even any waves breaking on the shore - I had imagined large waves breaking on the shore would be a big problem, but not on the days I was there. Here are some pictures of the invasion beaches in invasion weather:
Dungeness in good weather.jpg
Beach E in good weather.jpg
Beach C in good weather.jpg
Beach B in good weather.jpg
To see the other pictures go to https://www.facebook.com/Sealion1940/
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Re: Sealion compared to historical amphib assaults?

Post by pugsville » 25 Apr 2019 05:11

sitalkes wrote:
24 Apr 2019 00:10
Not all of them were river barges, many were coastal barges. There are five videos on YouTube of these barges crossing the channel in September/October (on tourist trips) without problems. The crossing would not have been made in a storm.
Are you really comparing apples with apples?

How heavily loaded were these barges?

Where they powered by 1940 engines?

What weather and meteorological information do they have compared to 1940?

Weather changes. teh Invasion could have begun then a storm could have come up.

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Re: Sealion compared to historical amphib assaults?

Post by sitalkes » 25 Apr 2019 05:43

The barges could carry 600 tons but even a fully loaded one is unlikely to have been carrying 100 tons. For example, the heaviest German tank at that time was the Panzer IV, which weighed 25 tons. A tank landing barge could carry three tanks - assuming they put three Panzer IVs on one barge (unlikely as they were relatively rare at that time and meant to be support tanks) - 75 tons in total. So lots of freeboard, even if you add 25 tons of supplies. The barges were fully enclosed. The modern barges are exactly the same size as the ones that were collected by the Germans, as they have to be to fit the canals etc. The modern barges making the crossing were not modified for it but may have more powerful engines than their 1940 equivalents, I'm not sure about that - but the Germans planned to lash together the powered and unpowered barges and tow them across. How practical that was I'm not so sure but it did create the problem of only having 400 or so tugs - if they were lost, then it was all over. In any case, the point is that their size and shape would not have prevented them from making the journey, destroyer wash and all, and you can watch them do it if you wish.
Weather changes did not prevent Caesar or William the Conqueror or other seaborne invasions of England/Wales/Scotland from happening (though they did have to wait for the weather to improve before they could cross). The massive storm after D-Day didn't prevent that from being a success -though it did destroy the American mulberry so that most American supplies were landed directly over the beaches for months afterwards - until Antwerp was captured. In any case, the weather in September/October 1940 in the south of England was remarkably good.
The Germans had broken the British meteorological code and the British naval code, and were able to read the British weather reports. They also got their own weather reports from weather ships in the North Sea/ Arctic, from the Russians (supplied under the Molotov Ribbentrop pact) , and from Submarines in the Atlantic. So their weather information wasn't that bad. In fact the British had worse weather information in some cases - their weather maps of Europe at that time had big blank spaces over Nazi-controlled areas. The Germans also got a lot of up-to-date information about shipping hazards in the invasion area from the British Admiralty via information supplied regularly to neutral nations.

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Re: Sealion compared to historical amphib assaults?

Post by Carl Schwamberger » 05 May 2019 02:16

Purpose built landing craft with experienced and highly trained crews routinely had trouble with coastal cross currents. Ditto for navigation and correctly identifying the correct beach. The Germans had completely inexperienced crews and naval staff for this, and underpowered barges or tugs dragging multiple barges. Realistically how many of the barges are going to fetch up on the correct beach? Most of the coast is not open beach how many barges will end the day bumped up at the base of a difficult cliff, floundering on rocks, or stranded on a shoal?

I'm thinking half the barges will reach the correct beach. Another 25% at the wrong beach but distracting the Brits, and another 25% out of the battle.

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Re: Sealion compared to historical amphib assaults?

Post by sitalkes » 05 May 2019 07:56

The German/French/Belgian/Dutch crews were often the crews of their own barges that had been requisitioned so they were very experienced in the use of their craft even if they had little or no sea experience. Some of the barges were coastal barges so some of the crews also had sea experience. Nevertheless "Operation Pigpile" was likely and to that end, hundreds of small boats were added to the fleet that were equipped with radios and navigation equipment so they could direct the barges where to go and keep the invasion fleets together. Most of the barges were in any case to be towed by sea-going tugs which were crewed by crews with sea experience. The landings were practiced often. For the Normandy landings, which were made in less than ideal conditions, the troops were landed in the wrong places on Omaha and Utah beach but the latter proved to be a blessing and they were still able to get off the beach in both cases. The German troops were all veterans of several campaigns of increasing difficulty and complexity unlike many of the troops who landed at Normandy, who (though well trained) had no combat experience at all. Yes many of the beaches were flanked by cliffs but shoals are not necessarily a problem for shallow draft landing barges. Yes mistakes would be made but the Germans would have had troops to spare if all had landed, as they had a 3:1 superiority in numbers in the invasion zone, were well equipped, and were confident, well led veterans . The Germans also practiced and trained for messed-up situations, and had good low level NCOs and officers (especially at that time of the war) who could cope without written orders and make the best of what they had. Crossing the channel at night was probably a dumb idea but we will never know how badly the invasion would have been messed up. We can show that other improvised German amphibious operations in the European theatre were successful.

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