If Doenitz had his 300 U-Booats after the Fall of France?

Given the devastation caused by a relative handful of U Boats had 300 been available which triples or Quadruples the number of boats at sea at any given time over OTL - and this will suddenly massively up the number of ships being sunk beyond a sustainable number month on month which means that the British have to react and react fast.

The quickest thing the Brits can do is retask Bomber command to coastal command (which is what they should have done OTL) given the impact a relative handful of aircraft had on the BOA suddenly having scores if not hundreds operating across the western approaches and as far as possible covering convoys is goign to cause the Uboat fleet many problems.

If the Germans can keep 4x as many Uboats at sea over OTL those voices will no longer be loud enough and the resources of BC will be transferred to Coastal Command

Then of course curtail any large warship construction and concentrate on building as many escorts as possible and training crews accordingly.

OK but there's a potential problem. If tonnage losses far exceed historical levels early in the war, the British will have fewer resources with which to implement alternative strategies.

Also I do not believe that the Germans building 300 U Boats by 1940 is achievable - recall that they had only started making them again in 1936

They had made relatively few down to '39 yet within three years, by the end of '42, had about 200 operational--despite the loss of 86 in '42 alone.
 

Redbeard

Banned
Actual history suggests Chamberlain would've been slow to implement a get tough policy.



As I wrote before they could've built many more U-boats had they not built Bismarck, Tirpitz, Scharnhorst, Gneisanau etc. By 1943 they were producing U-boats at a faster rate than before yet this hardly stopped tank production--plenty of Panthers and Tigers were being built.

Chamberlain could lead apeacement policy because Hitler yet wasn't a serious threat to British interests (ie ruling the seas and the Empire). In this context Hitler was much smarter than the Kaiser. Had he introduced a serious naval rearmament earlier he would have been removed at the first opportunity.

In 1943 German economy was on total war footing, which only had been introduced the year before and only climaxed in 1944. If we assume the Germans could have gone to total war economy much before we certainly can make a lot of PoDs. In 1943 alone Germany produced 30 times as many tanks and StuGs as in 1939, and a lot heavier too. When German economy didn't go on war footing before 1942 it was not because they preferred ploughshares or flowers but because they simply couldn't. German economy was already pressed to its limit and running short on anything from labour to capital and resources. In 1942 the desperation of the situation (after Stalingrad), the possession of teritories to exploit and the widespread introduction of slave labour - made total war economy possible. I don't see how that situation could have been provided before and certainly not without the world reeacting accordingly.

BTW not building capital ships for the Kriegsmarine probably will not provide resources for 50 U boats, and anyway, as soon as the Germans cross the limts of the Anglo-German Naval Agreement of 1935 it is game over for Adolf.
 
OK but there's a potential problem. If tonnage losses far exceed historical levels early in the war, the British will have fewer resources with which to implement alternative strategies.



They had made relatively few down to '39 yet within three years, by the end of '42, had about 200 operational--despite the loss of 86 in '42 alone.

There comes a point when the British (and Americans) have to 'drop everything' and concentrate on the Battle of the Atlantic - OTL the closest they came to 'dropping everything' was March 43 when it looked like the U-boats where once again getting the upper hand and they didn't have to drop everything as it tuned out that they had effectively won by May 43.

ITTL with more U-Boats the critical point comes much earlier and more has to be done to defeat the U-boats and LR Bombers etc - the fact is that the Allies can throw far more resources at the BOA than Germany can - particularly in the form of twin and four engine bombers which are equally at home missing targets in Germany as they are hunting U-boats in the western approaches.

In OTL U-boat construction and the then building U-Boat pens were almost totally ignored by Bomber command despite repeated requests from the Navy - in a situation where far more Merchant ships are being sunk then to the point where Britain's very existence is threatened then this would rapidly change long before it reached a tipping point.

I have just finished The Battle of the Atlantic by Jonathan Dimbleby which was a very good read and it is clear while both side missed many opportunities during the battle - by far the greater opportunities for improvement laid with the Allies who had the Numbers, resources, industry and Geography on their side and had the greater threat been apparent then they could have reacted very quickly - particularly in aircraft which would have had a massive and immediate impact to the on going battle.

Its actually stunning given the number of Bomber available to the allies why so little was provided to Coastal command (and to support the USN) before 43.
 
But Germany was building large warships like Bismarck, presumably to help counter the RN.

Except the British knew they were a minor threat and were in fact a complete waste of time. A mass U-Boat force can have only one aim and is a serious threat.



But they already faced the prospect of the Luftwaffe etc and down to early '39 the policy was to avoid through appeasement.

Yes but again that was not clearly aimed at the UK, 300 U-Boats is another matter.

Sure but look at actual history. Tonnage sunk by U-boats peaked in late 1942, when Britain, after the wake up call at Scapa Flow etc, had had three years to increase ASW forces. Most of the sinkings were in peripheral areas but the hypothetical 300 can include plenty of type IXs as well as VIIs and down to 3/'43 the latter, or convoy attacks, were still effective.

As others have tried to point out that was because of a slow response to a limited U-Boat threat, allow Doenitz his build up, which again as others have pointed out is all but impossible, and the British will shift their priorities.
 
Chamberlain could lead apeacement policy because Hitler yet wasn't a serious threat to British interests (ie ruling the seas and the Empire). In this context Hitler was much smarter than the Kaiser. Had he introduced a serious naval rearmament earlier he would have been removed at the first opportunity.


So the building of big warships like Bismarck and Tirpitz wasn't perceived as a threat to Britain?


BTW not building capital ships for the Kriegsmarine probably will not provide resources for 50 U boats,

IIRC Bismarck and Tirpitz were 45,000 tons apiece whereas U-boats averaged about 1,000. Add to that Scharnhorst and several other warships and that should boost the total to over 100, plus the 50 plus available historically. Not 300 but Doenitz did say he could've won in 1940 with twice as many boats as he had then.

and anyway, as soon as the Germans cross the limts of the Anglo-German Naval Agreement of 1935 it is game over for Adolf.

The nazis broke treaties like Locarno and broke their word by seizing all of Czechoslovakia early in '39--all with impunity for the time being. The Japanese btw built more and bigger warships than they were supposed to.
 
So the building of big warships like Bismarck and Tirpitz wasn't perceived as a threat to Britain?

No they really weren't, mainly because the RN massively outnumbered the Kriegsmarine. As OTL demonstrated they were largely a waste of resources. The most effective use of the Tirpitz was parking it in Norwegian Fjord.




IIRC Bismarck and Tirpitz were 45,000 tons apiece whereas U-boats averaged about 1,000. Add to that Scharnhorst and several other warships and that should boost the total to over 100, plus the 50 plus available historically. Not 300 but Doenitz did say he could've won in 1940 with twice as many boats as he had then.

A reasonable hypothesis, if you are clueless about ULTRA and assume the Allies will make no tactical changes in response to increased losses.

The nazis broke treaties like Locarno and broke their word by seizing all of Czechoslovakia early in '39--all with impunity for the time being. The Japanese btw built more and bigger warships than they were supposed to.

And you ignore the fact that after Munich Britain greatly accelerated it's military build up. And again appeasement was being sold against the background that Germany was no real threat to Britain, a massive U-Boat building programme rather scuppers that idea. You also keep ignoring the fact that the Allies had the means to defeat the U-Boats much earlier than they did, they simply didn't give the threat sufficient priority at the start of the war.
 
In my view the error is in the thread title. If the resources had been made available to give Dönitz 300 U-boats then France doesn't fall.
 

Redbeard

Banned
So the building of big warships like Bismarck and Tirpitz wasn't perceived as a threat to Britain?




IIRC Bismarck and Tirpitz were 45,000 tons apiece whereas U-boats averaged about 1,000. Add to that Scharnhorst and several other warships and that should boost the total to over 100, plus the 50 plus available historically. Not 300 but Doenitz did say he could've won in 1940 with twice as many boats as he had then.



The nazis broke treaties like Locarno and broke their word by seizing all of Czechoslovakia early in '39--all with impunity for the time being. The Japanese btw built more and bigger warships than they were supposed to.

The Germans stuck to the Anglo-German Naval agreement until very late. Going for a fleet of 300 U boats by 1940 would have broken said treaty many years before 1940.

I haven't reliable data on German warship cost, but I know that a Thames class fleet submarine (about a Type IX) in 1930 cost 500.000 £ and a T-class (which was more similar to a type VII) during the war cost 460.000 £ (Source: D.K. Brown, Nelson to Vanguard). A new battleship (KGV)would be about 7,5 million £. Bismarck would be more expensive than a KGV, a Scharnhorst less expensive (not at least because 11"ers are a lot cheaper than 14 or 15"ers). So 50 U-boats for the cost of the German capital ship programme would not be unreasonable. A ton of submarine is much more expensive than a ton of battleship, but a ton of aircraft will beat 'em all - unless we mention a ton of women's lingerie...

Concerning treaties the Anglo-German Naval Treaty (AGNT) allowed Germany 35% of the RN strength, but parity in submarines. The OTL naval programme was inside this until very short before the war and the AGNT was only renounced by Hitler in April 1939. If Germany had initiated a programme to have 300 U boats by mid 1940 the AGNT would have been obviously broken already at its signing. In OTL Hitler waited with re-occupying the Rhineland until after the AGNT - because he knew the British with that treaty wouldn't support the French in opposing a re-occupation of the Rhineland. The British were convinced that the AGNT prevented a naval race like that before WWI and their interests therefore preserved - until they realised after Munich that Hitler couldn't be kept at bay by feeding him.
 
A reasonable hypothesis, if you are clueless about ULTRA and assume the Allies will make no tactical changes in response to increased losses.

I don't think Kriegsmarine cyphers were broken as early as 1940. Of course more would've been invested in ASW had losses been substantially greater by 1940. The problem is, high losses in shipping would've shrunk overall British resources. Imports would've fallen and more of the diminished resources would've had to be invested in replacement tonnage. If they prioritized ASW under those conditions something else--maybe a lot else--would have to give....As Hoyt once suggested, keeping a stronger ubootwaffe under control in 1940 might've cost Britain the Near East and the allies a lot more in the long run.


And you ignore the fact that after Munich Britain greatly accelerated it's military build up. And again appeasement was being sold against the background that Germany was no real threat to Britain, a massive U-Boat building programme rather scuppers that idea.

More u-boats would mark Germany as a greater potential threat but appeasers could still claim Germany isn't after the British empire just a few states in eastern Europe--in fact the heightened threat should be avoided not risked, just by letting the reich take those states.


You also keep ignoring the fact that the Allies had the means to defeat the U-Boats much earlier than they did, they simply didn't give the threat sufficient priority at the start of the war.

Even historically, to deal with a modest sized ubootwaffe Britain, in 1940, had to beg the US for destroyers and ships. They just didn't have enough to deal with that modest force and apparently couldn't produce what they needed themselves. And if the threat had been about twice as bad, diminished resources would make matters even more difficult.
 
How 'bout 100-150? :) Doenitz apparently thought it would've sufficed.

And what evidence do you have Doenitz was right? he knew nothing of the impact of ULTRA intercepts. He advocated having his U-Boats conduct unlimited submarine warfare, including attacking US ships, which even Hitler knew was a bad idea and again he is assuming, as you are, that the Allies can/will do nothing in response to this larger U-Boat force.
 
I don't think Kriegsmarine cyphers were broken as early as 1940. Of course more would've been invested in ASW had losses been substantially greater by 1940. The problem is, high losses in shipping would've shrunk overall British resources. Imports would've fallen and more of the diminished resources would've had to be invested in replacement tonnage. If they prioritized ASW under those conditions something else--maybe a lot else--would have to give....As Hoyt once suggested, keeping a stronger ubootwaffe under control in 1940 might've cost Britain the Near East and the allies a lot more in the long run.




More u-boats would mark Germany as a greater potential threat but appeasers could still claim Germany isn't after the British empire just a few states in eastern Europe--in fact the heightened threat should be avoided not risked, just by letting the reich take those states.




Even historically, to deal with a modest sized ubootwaffe Britain, in 1940, had to beg the US for destroyers and ships. They just didn't have enough to deal with that modest force and apparently couldn't produce what they needed themselves. And if the threat had been about twice as bad, diminished resources would make matters even more difficult.

Just doubling the number of aircraft patrolling the Bay of Biscay and western approaches would suddenly make a U-boat Sortie in that area a virtual suicide mission and Britain could deploy many many times the number of aircraft that it did OTL

As I keep trying to point out Britain had a lot of Bombers in 1940 and 1941 and if the u-boat threat escalates X4 over OTL then bomber command does not become as big as it did and coastal command is suddenly a lot larger than OTL - it does not take much to saturate the seas around Britain with Aircraft.

If the Germans started building lots of U-boats then the rapid and only conclusion that can be arrived at is that they are intended to primarily blockade Britain and the British will react accordingly.

In my opinion ASW Aircraft / Coastal Command should have been prioritised over Bomber command and if increased numbers of Uboats in 1939 means that this happens then the War finishes earlier than it did as the Battle of the Atlantic would won earlier as the Allies pour more effort and resources into it than they did OTL allowing for an earlier invasion of France.
 

hipper

Banned
How 'bout 100-150? :) Doenitz apparently thought it would've sufficed.


The appropriate British reply to mass german uboat construction in the mid 1930's is to build armies, or even just give financial support to the French. Germany is walking a fine tightrope, it has started to rearm but cannot look too threatening untill it has completed its first wave infantry divisions in October 1936, mass U boat construction prior to this is impractical, staring mass U boat construction in 1937 is too late to build up a mass fleet of UBoats in 1939 and might provoke war in 1938.
 

Deleted member 1487

Just doubling the number of aircraft patrolling the Bay of Biscay and western approaches would suddenly make a U-boat Sortie in that area a virtual suicide mission and Britain could deploy many many times the number of aircraft that it did OTL

As I keep trying to point out Britain had a lot of Bombers in 1940 and 1941 and if the u-boat threat escalates X4 over OTL then bomber command does not become as big as it did and coastal command is suddenly a lot larger than OTL - it does not take much to saturate the seas around Britain with Aircraft.

If the Germans started building lots of U-boats then the rapid and only conclusion that can be arrived at is that they are intended to primarily blockade Britain and the British will react accordingly.

In my opinion ASW Aircraft / Coastal Command should have been prioritised over Bomber command and if increased numbers of Uboats in 1939 means that this happens then the War finishes earlier than it did as the Battle of the Atlantic would won earlier as the Allies pour more effort and resources into it than they did OTL allowing for an earlier invasion of France.
AFAIK the Brits didn't get effective at sinking Uboats by air until 1943.
 
AFAIK the Brits didn't get effective at sinking Uboats by air until 1943.

Aircraft were sinking U Boats with varying degrees of success from Jan 30th 1940 when U55 was sunk by a combination of Sunderland and Destroyer attacks - how many Uboats had to dive when an aircraft was spotted is unknown

But the most important thing is that no uboat will be operating on the surface if aircraft are overhead and this makes them slow and useless if they cannot spot targets so a convoy 'escorted by aircraft' is going to suffer fewer losses (Just saw Hippers post - totally agree)

Remember that there was relatively few Uboats active at this time and very few Aircraft hunting them - up the numbers of both and we would start seeing increased boat losses.
 

Rubicon

Banned
The Germans stuck to the Anglo-German Naval agreement until very late. Going for a fleet of 300 U boats by 1940 would have broken said treaty many years before 1940.

I haven't reliable data on German warship cost.
Bismarck 197M Rm
Tirpitz 181M Rm
Scharnhorst 146M Rm
Gneisenau 143M Rm
Hipper 86M Rm
Blücher 87M Rm
Prinz Eugen105M Rm
Flugzeugträger 92M Rm
Graff Zeppelin 93M Rm

Type VIIA 4.189.000 to 4.439.000 Rm
Type VIIC 1.983.000 RM
Type IXB 6.163.000 to 6.448.000 Rm
Type XB 6.350.000 Rm
Type XI 17.410.000 Rm
Type XXI 4.600.000 RM


Have fun :cool:
 
I don't know exactly but i think that 300 submarines would be equal to 2-3 Panzer Divisions(anyone that knows more can say if that is correct?)
So,if he manages to convince Hitler that they need to win the BoB in the water,what would be the effects of such decision?I think that IF they won in Britain the subs can be melted to tanks in 6 months-1 year

If I just press this magic button here.....

*poof*

3 Panzer divisions are magically converted on 22 June 1940 into 300 U-Boats and the personnel who were formerly army are now fully trained in naval submarine warfare instead.

Surely this belongs in ASB?
 

Deleted member 1487

Does not matter
Air escort of convoys prevents the U boats sinking ships, which is the whole point.
Sure, but the comment I was responding to said that aircraft would make Uboats a suicide-mission. It wouldn't before 1943, but it would dramatically reduce their effectiveness.

Aircraft were sinking U Boats with varying degrees of success from Jan 30th 1940 when U55 was sunk by a combination of Sunderland and Destroyer attacks - how many Uboats had to dive when an aircraft was spotted is unknown

But the most important thing is that no uboat will be operating on the surface if aircraft are overhead and this makes them slow and useless if they cannot spot targets so a convoy 'escorted by aircraft' is going to suffer fewer losses (Just saw Hippers post - totally agree)

Remember that there was relatively few Uboats active at this time and very few Aircraft hunting them - up the numbers of both and we would start seeing increased boat losses.
About 2 months ago I read a book about British operations research as applied to the BotA and how and when aircraft became effective at sinking Uboats....which was in 1943 when they got the right techniques and equipment for the job. (Blackett's War is the book). Some Uboats were sunk before then, but prior to 1943 they were primarily for spotting Uboats and forcing them to dive, which reduced their ability to intercept convoys dramatically. Again I was just speaking to your claim that they'd be slaughtering Uboats from the air with more aircraft for Coastal Command; they wouldn't, specifically because Bomber Command lacked the equipment and training to do the job and CC wasn't doing it that great either, but they were forcing them to dive or at least spotting them for convoys to get out of the way. THAT would be the important part, reducing intercepts and Uboat ability to operate on the surface effectively.
 
the KM would not need the extreme of "300 u-boats!!" to have been deadly effective. they could have built a force of 100 - 300 tonne u-boats, transportable by rail, in somewhat greater numbers (say approx. 100 in the various displacements)

probably can be somewhat concealed from Allies, the numbers at any rate would probably not provoke much change in RN construction plans?

if they built smaller coastal u-boats it would help solve (somewhat) shortage of trained crews.

the building of larger u-boats probably would be harmed by mass production (300) of one type as they needed evolutionary changes? there were several advancements short of the Elektroboat that could have been made.
 
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