WI Better Kriegsmarine in WW2

[Grand Admiral Thrawn]

The crux of there problem, is the reaction time to the invasion. The MLs only do 12kts, the barges 5kts. How far the Germans get before the MLs can close, and how much damage before the destroyers and daylight arrives????

The RAF fighters only have limited range of comms from ground control, losing their advantage. And fixed escorts to fleet uses up considerable resources.

Reaction time is measured in days though, not hours. Getting to the beach isn't an insta-win, Germany has to land an army, resupply it, and most importantly reinforce it *then* get off the beach. You handwaved away the 24-48 hours the British would have (they can see Calais from Britain), but even a surprise raid so the Germans get 12 hours free, British ships will sink barges on D+1, D+2, etc, crippling the Germans. No additional troops, no artillery (first wave didn't have heavy artillery), the British really have 3-5 days to crush Sealion. Not 3-4 hours.

 

[Capt Thunderbolt]

Reaction time is measured in days though, not hours. Getting to the beach isn't an insta-win, Germany has to land an army, resupply it, and most importantly reinforce it *then* get off the beach. You handwaved away the 24-48 hours the British would have (they can see Calais from Britain), but even a surprise raid so the Germans get 12 hours free, British ships will sink barges on D+1, D+2, etc, crippling the Germans. No additional troops, no artillery (first wave didn't have heavy artillery), the British really have 3-5 days to crush Sealion. Not 3-4 hours.

No hand waving......Until "destroyers or day light arrives"

Then it ends.

 

[Grand Admiral Thrawn]

No hand waving......Until "destroyers or day light arrives"

Then it ends.

Apologies, your handwaving is that the RN only has hours to attack the barges, when they will know an invasion is likely by D-1 or possibly even D-2 (that is, 1 or 2 days *before* the Germans set sail). Even motoring along at 5 knots (as an example, they would go faster) is plenty when you have 6-8 hours of darkness to surge forward D-1, since again the British only have to defend the British side of the Channel, not the whole or French side.

 

[Capt Thunderbolt]

Apologies, your handwaving is that the RN only has hours to attack the barges, when they will know an invasion is likely by D-1 or possibly even D-2 (that is, 1 or 2 days *before* the Germans set sail). Even motoring along at 5 knots (as an example, they would go faster) is plenty when you have 6-8 hours of darkness to surge forward D-1, since again the British only have to defend the British side of the Channel, not the whole or French side.

The crossing it not the weakest part of the plan, the landing is. The cross decking and assault is a nightmare. This is a much better target.

 

[Grand Admiral Thrawn]

@Capt Thunderbolt are you saying (quote) "The crossing it not the weakest part of the plan, the landing is." for the British or the Germans? Because the landing is the weakest, but the crossing is pretty weak too, since the British will literally have 24-48 hours notice before the invasion even sets sail. That means destroyers, trawlers, cruisers, and a spare R class battleship or 2 will be prepping for battle. Like, the Germans have to fight across the Channel, they can't sneak attack at all. And the British still have 3-4 days after the landing to cut the reinforcements to pieces.

If you meant the British, the crossing is the best, since they have enough forces to win it soon enough. The landing is more dangerous, as the Home Guard has to hold long enough for the army to show up (countered by no German Panzer divisions to stop).

 

[Capt Thunderbolt]

since the British will literally have 24-48 hours notice before the invasion even sets sail

As posted before, it should be more. Operation starts at S-5, minelaying at S-9.

Both sides had radar on the channel, neither thought the other was watching! Britain had already a false alarm, the Cromwell codeword sent.

You have got to hope it's real invasion and not a false attack, before sending all that hardware into the channel.

 

[Grand Admiral Thrawn]

As posted before, it should be more. Operation starts at S-5, minelaying at S-9.

Both sides had radar on the channel, neither thought the other was watching! Britain had already a false alarm, the Cromwell codeword sent.

You have got to hope it's real invasion and not a false attack, before sending all that hardware into the channel.

Why do the British have to hope it's the real deal? Are the ships only there because the RN is using a "Buy 1, get 1 free sortie" coupon? Is the Treasury sending auditors to make sure it is a real raid and not a fishing trip on HMG monies? Remember, although you do have a point of how the RN is overegged in any plausible Sealion (German troops almost certainly get ashore, and the RN will lose ships), none of that matters...

Because the Germans can't pick off any ships with a false sortie
Because the Germans would lose so many ships and barges attempting Sealion that Britain is safe for 12-18 months
Because Britain can afford to lose 1:1 and will still prevail

Your recent argument seems to be focusing on a specific matter that yes, the British do have to worry about, and you hold it triumphantly as if that means it is insurmountable. But Germany faces far more problems that are truly insurmountable, and not just a heavy price to pay. So I have to ask, what difference does it make if not all 300 trawlers and smaller can't say over 12 knots, or to France, or have to worry about if this is the invasion (although they are not in muddy trenches in Flanders, but in warm cots on board or in port, and Germany can't do fake-outs; not many other targets around), when the British will stay on their side of the Channel, as the Germans *must* attack them, not the other way around. If Sealion was a British attempt to invade France, it would still be a failure (although some degrees less costly). But the RN literally doesn't need luck; the KM has to roll 7's on a 6 sided die (ie, need an ASB to win).

 

[Gudestein]

The crossing it not the weakest part of the plan, the landing is. The cross decking and assault is a nightmare. This is a much better target.

View attachment 687815

Where is this map from?

 

[Garrison]

The crossing it not the weakest part of the plan, the landing is. The cross decking and assault is a nightmare. This is a much better target.

View attachment 687815

There is a huge problem with the above map in that Romney Marsh is not exactly an ideal bit of land for the Germans to try and establish a bridgehead, even assuming the airborne landings, which the British were fully expecting, don't get cut to pieces. Look what happened in the Hague against the Dutch. Are they really going to do better against a first rate airforce with radar to guide them in a part of the country full of British troops and prepared positions?

Romney Marsh WWII

Battle for the Hague

 

[Capt Thunderbolt]

There is a huge problem with the above map in that Romney Marsh is not exactly an ideal bit of land for the Germans to try and establish a bridgehead, even assuming the airborne landings, which the British were fully expecting, don't get cut to pieces. Look what happened in the Hague against the Dutch. Are they really going to do better against a first rate airforce with radar to guide them in a part of the country full of British troops and prepared positions?

Romney Marsh WWII

Battle for the Hague

A huge big problem, especially if flooded. Considering it's reclaimed land I thought the flooding would be worse.
Along the Jurys gap rd, the land is waterlogged, surprising not as much as I expected.
The first and Blue flood map, shows flooding would not be as rewarding as hoped.
But is significant as you approach the military canal and pillboxes.
And btw Burmarsh and Hythe.
The assault map is from

 

[Garrison]

A huge big problem, especially if flooded. Considering it's reclaimed land I thought the flooding would be worse.
Along the Jurys gap rd, the land is waterlogged, surprising not as much as I expected.
The first and Blue flood map, shows flooding would not be as rewarding as hoped.
But is significant as you approach the military canal and pillboxes.
The assault map is from View attachment 687894

View attachment 687890




View attachment 687889
View attachment 687887
View attachment 687886

The British would have flooded it to stop an advance and I suspect your original map shows a profound lack of knowledge of the local terrain on the part of the Sealion planners.

 

[Capt Thunderbolt]

The British would have flooded it to stop an advance and I suspect your original map shows a profound lack of knowledge of the local terrain on the part of the Sealion planners.

I am not so sure on that!

German hydrogeological maps prepared for Operation 'Sealion': the proposed invasion of England in 1940
Edward P. F. Rose" John D. Mather! & Dierk WiIlig2 ROSE, E. P. F., MATHER, J. D. & WILLIG, D. 2002.

German hydogeological maps prepared for Operation 'Sealion': the proposed invasion of England in 1940. Proceedings of the Geologists' Association, 113, 363-379. During the Second World War, German military geologists assisted preparation for an invasion of Britain planned for September 1940. A military geology group deployed in support of the German 16th Army generated ten 1:50 OOO-scale water-supply maps plus accompanying explanatory texts to cover southeastern England. Two additional military geology units generated at least nine water maps for the adjacent south-central areas assigned to the 9th Army, maps different in their presentational style and in adopting 1:100000 and 1:250000 as well as 1:50000 scales. Initially, water was to be obtained by both armies from untapped springs and drive wells: partly-perforated steel tubes hammered <7 m into suitable ground. Topographical base maps were derived from Ordnance Survey maps ofthe most similar scale. These were annotated by the geologists to show positions of springs of different types, key engineering works, regions differing in well-driving potential, and regions of contaminated or brackish groundwater, with more detail shown on 16th than 9th Army maps. Preparation essentially within the late July to mid-September 1940 time frame was made possible by extensive use of Ordnance and British Geological Survey publications, information readily available. rather than data from other sources. The maps were important aids to operational planning since substantial quantities of potable water were required for both men and horses of the two invading armies. From hindsight and more detailed local knowledge, it seems that the maps would have been useful but imperfect guides to obtaining adequate supplies of drinking water. I

Department of Geology, Royal Holloway, University ofLondon, Egham, Surrey TW20 OEX,UK 2Dezernat Wehrgeologie, Abteilung Geophysik, lJ (GEIUS) Korps, Stuttgarter Strasse 199, D-89081 Ulm, Germany

 

[Capt Thunderbolt]

The British would have flooded it to stop an advance and I suspect your original map shows a profound lack of knowledge of the local terrain on the part of the Sealion planners.

While I'm on the subject, had a look at ships sunk off Dunkirk.
Relatively few destroyers sunk. But when you look at ship losses an interesting pattern is noted.
I've re-sorted ships sunks at Dunkirk by displacement. Red sunk, pink hospital ships (protected though one was sunk)

 

[eltf177]

[snip]There is a huge problem with the above map in that Romney Marsh is not exactly an ideal bit of land for the Germans to try and establish a bridgehead...

From what I've learned from our UK bretheren is that there aren't many beaches suitable for landing, and these of course were heavily defended.

The German's need surprise, and that just wasn't going to happen. And given the ad-hoc buildup I don't see many barges returning for a second trip to England - any troops who land won't be resupplied except by air so expect an earlier version of the Stalingrad disaster...

 

[dave_r_gilbert]

The British would have flooded it to stop an advance and I suspect your original map shows a profound lack of knowledge of the local terrain on the part of the Sealion planners.

I agree. Having had a few holidays in the area, I know it reasonably well.
Everything marked on the german map as "Kusten-Niederrung" is reclaimed salt marsh, flat as a pancake, and laced with drainage ditches.
The soil is thick, gloopy, and permanently soggy.
I suspect the risk of flooding map, has the high risk areas around the edge due to the proximity of high ground (the south downs) where water could run off into the marsh.
This reflects the risk of accidental flooding, not deliberate.
Turning some pumps off, others on, and redirecting the sluices wouldn't take long.
In a country not renowned for desert like conditions, keeping the water out of a drained salt marsh is a problem.
Deliberately flooding one not so much.
By the way, the entire area of the marsh, and the shore line, is visible to anyone with a pair of binoculars anywhere along the south downs to the north.

 

[Capt Thunderbolt]

I agree. Having had a few holidays in the area, I know it reasonably well.
Everything marked on the german map as "Kusten-Niederrung" is reclaimed salt marsh, flat as a pancake, and laced with drainage ditches.
The soil is thick, gloopy, and permanently soggy.
I suspect the risk of flooding map, has the high risk areas around the edge due to the proximity of high ground (the south downs) where water could run off into the marsh.
This reflects the risk of accidental flooding, not deliberate.
Turning some pumps off, others on, and redirecting the sluices wouldn't take long.
In a country not renowned for desert like conditions, keeping the water out of a drained salt marsh is a problem.
Deliberately flooding one not so much.
By the way, the entire area of the marsh, and the shore line, is visible to anyone with a pair of binoculars anywhere along the south downs to the north.

Just blowing the seawall should do the job, most of it is 2 m above mean sea level! Dowels near Snargate only 0.3m.

And leaving the summer boards in the sluices and letting the level rise will keep it so.

Being so flat and waterlogged, the flooding will be the same for natural or deliberate flooding.

The Germans don't have many options, and this is a least bad one! The German first wave left most of their vehicles behind.
They are going to have to trudge through there. The same for defenders in that area.

 

[Capt Thunderbolt]

McPherson said:
...The Graf Zeppelib cats never worked as hoped. Never. In practice the Germans would have jatoed.

aaand once again : what's the source of your 'wisdom' ? ... any reports ? ... or similar ?

The German’s catapult design was tested in 1940, using a 66 foot long barge-mounted pneumatic catapult, moored in
the Trave River estuary. Two different types of aircraft intended for eventual deployment on the German carrier were
hoisted by crane onto collapsible launch carriages positioned on the barge-mounted test catapult.
After dozens of test launches, duplicating the conditions expected onboard the GRAF ZEPPELIN, German officials were fully satisfied
with the catapult system’s performance. Those tests also gave German aviators their first taste of being catapulted over water.

 

[NOMISYRRUC]

FWIW this area was defended by an armoured train that ran along the Romney Hythe & Dymchurch Railway.

 

[Capt Thunderbolt]

FWIW this area was defended by an armoured train that ran along the Romney Hythe & Dymchurch Railway.

Not much help if you flood the area !


During World War II, a miniature armoured train was used on the line to patrol the coast in case of invasion. The train consisted of No. 5 Hercules and a few wagons fitted with armour plating and armed with a Boys anti-tank rifle and Lewis guns.[10][49]

 

[sonofpegasus]

This the train in question.