Dunkirk Evacuation Prevented By Mines

  • Thread starter Deleted member 1487
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Deleted member 1487

What if the Germans waited to deploy their magnetic mines until the invasion of France? Then, when using mines to block ports during the invasion of the Lowlands and France, they drop several hundred/1k+ at Dunkirk, which the British ITTL will have never encountered and have no countermeasures for?
OTL there were only about 2 days that the Luftwaffe could fly, but that is plenty of time to spam the port with mines using multiple sortees. The British OTL were seriously afraid of the magnetic mines when they first encountered them because they had no counter measures and didn't really have any effective method for sweeping them until IOTL they captured one that was accidentally dropped on land near London in 1939.

Without the critical methods of sweeping learned by this capture the British would suffer unacceptable numbers of losses in the evacuation, which means it stretches out for several weeks or is abandoned altogether. What does this mean politically and militarily? Do some men still get out, does the RN still risk the evacuation?
 
Did Germans have enough of these mines? One ofthe reasons campaign failed is hat they had limited number and, like the Uboats, they showed their arm too early, enabling Allies to devise effective counter-measures. Although, on reflection, it does make sense that they could have enough mines and without the lucky strike for British it migh just be viable.

However, Germans could not foresee the need to use those mines at Dunkirk and it would be very hard for them to refrain from using them at first opportunity.
 
Prevent the British from developing countermeasures to the German Magnetic Mines, specifically by delaying them from finding such a device as on the Thames, and they will remain effective as an actual weapon. The Luftwaffe could then drop a few such devices along the coast, but not an extensive number.
 
Did Germans have enough of these mines? One ofthe reasons campaign failed is hat they had limited number and, like the Uboats, they showed their arm too early, enabling Allies to devise effective counter-measures. Although, on reflection, it does make sense that they could have enough mines and without the lucky strike for British it migh just be viable.

However, Germans could not foresee the need to use those mines at Dunkirk and it would be very hard for them to refrain from using them at first opportunity.
Well, they could have dropped them at important ports to prevent supply and, coincidentally, they end up preventing the Dunkirk evacuation. They do need a large number of them to do it, though.
 

Deleted member 1487

Did Germans have enough of these mines? One ofthe reasons campaign failed is hat they had limited number and, like the Uboats, they showed their arm too early, enabling Allies to devise effective counter-measures. Although, on reflection, it does make sense that they could have enough mines and without the lucky strike for British it migh just be viable.

However, Germans could not foresee the need to use those mines at Dunkirk and it would be very hard for them to refrain from using them at first opportunity.

There was strong pressure by the Luftwaffe to keep the mines in reserve until they could be available in sufficient number (~2500) for use against British ports. They could too meant that the Lowlands would have to be captured before they could be effectively used against the British. The Navy decided to use them against pre-war planning agreements and were the ones that dropped the mine that would be captured.

There would have been probably 3000 ready by June 1940. So yeah, they would have had plenty ready and had several specialist minelaying naval bomber units. IIRC there were something over 150 bombers trained for minelaying from the air in 1940. Using all of them around Dunkirk could well see several hundred deployed in 2 days. IOTL 150 closed the Thames for 2 weeks in 1939, before the sweeping methods were developed.

So have the Kriegsmarine not use them as per the pre-war plan. Have the first uses be during the invasion of the Lowlands, so that by the time Dunkirk happens, they are still a surprise and the Allies have no methods of sweeping them.


Well, they could have dropped them at important ports to prevent supply and, coincidentally, they end up preventing the Dunkirk evacuation. They do need a large number of them to do it, though.
Not really. 150 closed the Thames for 2 weeks IOTL after an entire coastal convoy of ships (14) was sunk by them.


Prevent the British from developing countermeasures to the German Magnetic Mines, specifically by delaying them from finding such a device as on the Thames, and they will remain effective as an actual weapon. The Luftwaffe could then drop a few such devices along the coast, but not an extensive number.
Why not a large number? They had about 1000 when the war started and by June 1940 were probably going to have about 3000 on hand. They also have about 150 trained minelaying bombers to deploy them as of May 1940.
 
Why not a large number? They had about 1000 when the war started and by June 1940 were probably going to have about 3000 on hand. They also have about 150 trained minelaying bombers to deploy them as of May 1940.
Thought that they were rarer than that, usually in favor of more conventional devices.

Suffice to say if dropped around the area of the harbor alone, they could do quite a bit of damage; The Little Ships if caught in the shock wave would in most cases I believe be sunk. Therefore, it is possible fewer such vessels even make the trip.
 
Most of the little ships wouldn't be affected by magnetic mines as they were built of wood, and the Germans would be more likely to use the mines against English ports than the French ports. First it keeps the british ships in port and second it saves them the trouble of having to clear the mines themselves once France surrenders. You have also discounted Fighter Command. They would not have sat on the ground and allowed the Germans to lay these mines without interference. While the myth of Dunkirk is that they had no air support it's not true, it's just that most of the air combat took place out of sight of the troops. Less of the BEF would be evacuated but the British only expected to be able to evacuate around 40,000 anyway. Also the British had more troops in France than were penned in at Dunkirk who kept fighting right through June and into July. Added to the forces withdrawn from Norway there would be a solid foundation to rebuild the army.
 
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Most of the little ships wouldn't be affected by magnetic mines as they were built of wood, and the Germans would be more likely to use the mines against English ports than the French ports. First it keeps the british ships in port and second it saves them the trouble of having to clear the mines themselves once France surrenders. You have also discounted Fighter Command. They would not have sat on the ground and allowed the Germans to lay these mines without interference. While the myth of Dunkirk is that they had no air support it's not true, it's just that most of the air combat took place out of sight of the troops. Less of the BEF would be evacuated but the British only expected to be able to evacuate around 40,000 anyway. Also the British had more troops in France than were penned in at Dunkirk who kept fighting right through June and into July. Added to the forces withdrawn from Norway
With the Little Ships I was thinking more along the lines of those which would be effected by the shock waves of those mines triggered by those vessels which do have metal content; they weren't contact mines but typically detonated (10) meters below the surface. If caught in the Shock Wave the Wooden Vessels would be liable to have their bottom turn out from under them, I figure.

And of course the Air would not be uncontested, but I am not sure how much of a difference that might make in the scheme of things.

 
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