WI: Causewaylion? The Nazis try to build a causeway to Britain after defeating the Soviet Union.

[RamscoopRaider]

What if you built the causeway out of sunken Rhine barges?

Then you need to build a lot more Rhine barges to have enough, might as well just build proper landing craft and destroyers for a conventional landing

 

[Enigmajones]

Gotta say this is one of the most ASB concepts I've ever heard. If it was attempted, its likely the British would continually bomb the attempted causeway making sure it never gets finished.

 

[marathag]

Assuming Team Lead Tea has the right of it and the causeway can get built sometime before the war is over... what's stopping a couple of MG nests and an AT battery from setting the Germans right back to square one? This is the Great Ardennes Traffic Jam all over again except the Allies are prepared for it.

As bad as it is, is still a way to get an army across the Channel, something the KM couldn't ever do
Because honestly, even teleporting a couple divisions intact doesn't make SeaLion work, so everything is pointless in the end.
But the Mole, that's _Style_ in action

 

[GuildedAgeNostalgia]

Decoy causeway to hide German attempts to tunnel under the Channel?

 

[Post]

I like the idea.

If the germans build a forest of anti-airguns and put all their big guns (yes, I am looking at both Schwerer Gustav guns) there and dont forget to make sure the guns can be elevated up to 45 degrees then I dont see the british having much chance.
As one mentioned, it is the BoB reverse because the British have to come to the german side of the channel and if a british pilot is shot down he ends up as POW. And the german artillery can attack any target in South England. And if they can be elevated enough the ships of the Royal Navy can be targetted by the german artillery before they can fire back.

And the Nazis have enough manpower - if they dont kill those they do not like. Send them all to the channel to build the causeway.

Except that the British don't have to attack it with the RAF the way you think. As mentioned, nightattacks by the RN will do fine. Or long range artillery. Or night attacks by the RAF.

Or they can just sit and wait until the Germans are within a few miles of the english coast and they have the home advantage. It will take years for the Germans to get that far.

Or they can just wait till the Germans get it done and in the meantime build up defences on their side. The British will biild up defences faster than the Germans, and when the Germans finally attack, the very heavy defences eat the single Ratte that is the spearpoint of the attack. The ensuing block of the causeway causes the attack to halt.

Or they simply attack the traffic jam on the causeway, causing enormous carnage. And no, it won't cost them the whole RAF, they can simply do it at night with the RN, which still heavily outmatches the KM. Or otherwise, due to ther no being a BoB, the RAF outmatches the LW anyway.

 

[DJ03]

Decoy causeway to hide German attempts to tunnel under the Channel?

Seriously: did the germans have the ability to dig all the way to somewhere in Kent? Not interested in if they can invade britain this way, just want to know if an alt-chunnel can physically be dug from only one side during the war

 

[Albidoom]

Seriously: did the germans have the ability to dig all the way to somewhere in Kent? Not interested in if they can invade britain this way, just want to know if an alt-chunnel can physically be dug from only one side during the war

Give how deep the coal mines in the Ruhr area are Germany technically does have the needed knowledge and technologies. Of course digging out a tunnel for several dozen miles would already be quite a logistical challenge in peacetime in friendly territory. During wartime in occupied territory with an enemy determined to not let you succeed is a whole different beast.
And in the end you got a supply line that basically screams "Bottleneck!" along the entire way (of course should someone sabotage the ventilation then the screaming in the tunnel will subside rather sooner than later)

 

[CaptainCalvert]

Decoy causeway to hide German attempts to tunnel under the Channel?

The tunnel is itself a decoy for the attacks via Shetland, Iceland and the Isle of Wight. Bet you weren't expecting that you Britische Schweinhunde!

 

[steamboy]

The tunnel is itself a decoy for the attacks via Shetland, Iceland and the Isle of Wight. Bet you weren't expecting that you Britische Schweinhunde!

Oh god Wightlion... *winces* The goal post moving, the blatant Nazi sucking off and lunancy...

 

[danielb1]

Less ASB than my idea of German soldiers crossing the channel by riding on the backs of trained sealions, at least. 😛

Seriously, building a land causeway over the channel is technically possible but doing so in the middle of a shooting war is infeasible unless the British sonehow collectively ignore it.

 

[BELFAST]

even less plausible than this

 

[Ramontxo]

I like the idea.

If the germans build a forest of anti-airguns and put all their big guns (yes, I am looking at both Schwerer Gustav guns) there and dont forget to make sure the guns can be elevated up to 45 degrees then I dont see the british having much chance.
As one mentioned, it is the BoB reverse because the British have to come to the german side of the channel and if a british pilot is shot down he ends up as POW. And the german artillery can attack any target in South England. And if they can be elevated enough the ships of the Royal Navy can be targetted by the german artillery before they can fire back.

And the Nazis have enough manpower - if they dont kill those they do not like. Send them all to the channel to build the causeway.

By summer 1942 the British were sending one thousand bombers raid to Colonia. Several thousand metric tons are going to make an impact in the works. The channel is over thirty kilometres in its narrowest place. This "forest of flak" is not going to protect it.

 

[Coulsdon Eagle]

Doggerland is the answer!
It was the original land bridge until about 10,000 years ago
Start by raising an island or two on the Dogger bank then work out from there.

The work could be aided by using whilte paint and reflective surfaces to reduce solar gain over occupied Europe. The resulting mini ice age will help lower sea level so that more land is exposed.

Like most worthwhile challenges, it just needs ingenuity, money and determination.

So, Dogger Bank I is a naval battle, Dogger Bank II is a land battle. I like this!

 

[Post]

By summer 1942 the British were sending one thousand bombers raid to Colonia. Several thousand metric tons are going to make an impact in the works. The channel is over thirty kilometres in its narrowest place. This "forest of flak" is not going to protect it.

With the accuracy of the time 95% or more of the bombs fall in the sea.

But there indeed is no forest of flak, because on work in progress there is little room for it.

 

[marathag]

even less plausible than this

Long ago I did put forth of using Longboats for the alternate SeaLion. And it used non-strategic materials
Because, of all the ones at that table, only the rowed longships succeeded in placing enough troops onshore to control large areas of territory

 

[Ramontxo]

With the accuracy of the time 95% or more of the bombs fall in the sea

Not really (and yet 5% of two thousand tons are 100 hundred kilograms of bombs, each time) 15, 20 kilometers inside the Channel the flak placed in Calais is not a factor. Say that light flak, even Kriegsmarine boats are placed along the 30 kilometers long construction. British bombers would be coming at 3000 meters (around 9000 feet) slow and over ligth flak.

Edited to add that I, obviously agree with your second point

 

[Cryhavoc101]

I see no issue with this plan at all - nope uh uh - not a hair out of place

Obviously the British would wait until it was finished and then as the first German tanks started to cross the causeway under the cover of darkness to maintain the ahem element of surprise they hear strange music......

I...I have something in my eye

 

[JasTysoe]

In terms of volume, there are any number of dams. In terms of construction approach, it's not fundamentally different to a large mole or breakwater.

The most significant comparison is the Afsluidijk, which was constructed between 1927 and 1932 to close off the Zuiderzee - until that time a tidal bay of the North Sea - and which is about two-thirds the volume of the proposed English Channel causeway.

The vast fundamental difference is that no one builds moles or breakwaters that block such vast and powerful tidal flows. The tide at Dover rises and falls about 7m twice a day, running about 2-3 knots. There are long stretches over the narrows where the water is 50m deep at high tide - ten times as deep as the Ziuderzee. As a dead end, rather than a link between the Atlantic and the North Sea, the Zuiderzee would have had nothing like the tidal flow. Even sinking the Mulberry blockships in the slow moving waters in the shallows was a challenge that wasn't always met.

Calculate the forces involved in a 50km wide bit of water with an average depth of about 40m moving at 5-6 kmh. It would be the biggest engineering challenge ever seen by an enormous amount. And then calculate how much the inevitable restruction of the tides will effect the shorelines in the areas. Also consider how to build proper foundations and exactly how you place boulders in a 3 knot tidal flow.

While you're about it, consider that even one of the Mulberries - specially built and protected by blockships, largely out of tidal flow and in shallow water - fell apart in one gale. Multiply that by the depths and forces involved in a Channel crossing....

The only material that could be used for this project is ASB wings and unicorn tusks reinforced with unobtainium and held in place by crystallised angel farts.

 

[JasTysoe]

I was assuming that the causeway would be constructed out of materials hard for a current to wash away, namely large boulders. At least at the beginning, the boulders should not be vulnerable to erosion. As the channel is narrowed, the current will strengthen and the Nazis will have to increase the size of their boulders.

Anyone who has looked at the history of breakwater construction would know that no boulders are big enough to block the extremely powerful tides of the Channel, a very narrow strait between two very large areas.

 

[weasel_airlift]

Problem is, even if you somehow manage to complete it, where it comes ashore is a killing ground. A fairly small force can stop the entire Nazi army just about indefinitely. Even if the Luftwaffe can keep the RN and RAF off of it, a natural choke point like that is a defender's dream.