start small! Type XXIII Elektroboot

the type that sank last Allied ship in European front https://en.wikipedia.org/wiki/SS_Avondale_Park

probably the best scenario for KM would have been to modify existing Type VII u-boats with some of advances for proposed Elektroboot, streamlined conning tower, remove deck gun, more batteries and stronger electric motors ...

while introducing smaller Type XXIII and one or more of the conventional mini-submarines (Seehund, Seeteufel tracked sub) to confuse the issue for Allied side.
 
I am sceptical with regards to getting the technology to work reliably and robustly in this time period - OTL they did not really manage it and the Allies and Russians took some time post war to mature it and some aspects were dropped.

Also Late 44 is too late the Battle of the Atlantic was won by May 1943 and this mini sub introduced to try and rewin the battle would be subjected to the same combination and alignment of war winning technology, weapons, intel and sufficient and experianced escorts / Escort Carriers + increasing numbers of technically advanced VLR MPAs armed with weapons such as FIDO which the XXIII could not outrun! Well not for long anyway.
 
the type that sank last Allied ship in European front https://en.wikipedia.org/wiki/SS_Avondale_Park

probably the best scenario for KM would have been to modify existing Type VII u-boats with some of advances for proposed Elektroboot, streamlined conning tower, remove deck gun, more batteries and stronger electric motors ...

while introducing smaller Type XXIII and one or more of the conventional mini-submarines (Seehund, Seeteufel tracked sub) to confuse the issue for Allied side.
Thanks for letting me know about the seeteufel. I shall never forget this.
Has there been any seeteufel based Sea lion threads yet? That may yet need to see the light of day.
 
In his book HITLER'S U-BOAT WAR: THE HUNTED 1942-1945 by Clay Blair Jr. he mentions sailing on a Type XXI postwar. He said it leaked like a sieve (they were built in sections and welded together in the yards). It was a good design but not sufficiently mature enough as a weapon system plus there were many quality control issues. I have no doubt the Type XXIII had similar problems...
 
I am sceptical with regards to getting the technology to work reliably and robustly in this time period

Also Late 44 is too late the Battle of the Atlantic was won by May 1943 and this mini sub introduced to try and rewin the battle would be subjected to the same combination and alignment of war winning technology, weapons, intel

my reading the peroxide was dropped and am not suggesting that it would be successful if they simply concentrated on the smaller variant.

also not suggesting a Battle of Atlantic redux but simply concentrating on the smaller (1/8th displacement) Type XXIII they might have made it into service ... for coastal defense.
 
In his book HITLER'S U-BOAT WAR: THE HUNTED 1942-1945 by Clay Blair Jr. he mentions sailing on a Type XXI postwar. He said it leaked like a sieve (they were built in sections and welded together in the yards). It was a good design but not sufficiently mature enough as a weapon system plus there were many quality control issues. I have no doubt the Type XXIII had similar problems...
Also design flaws - hydraulics were outside the pressure hull, which limited diving depth to c500ft.
 
Thanks for letting me know about the seeteufel. I shall never forget this.
Has there been any seeteufel based Sea lion threads yet? That may yet need to see the light of day.

that minisub Seeteufel sounds like a joke but it actually addressed the problems launching vessels at that stage of the war, every book I can find cites good underwater handling, and a more powerful diesel motor was projected for (any) production model.

my view with hindsight the KM should have built the smaller Elektroboot as it could be transported overland and the Seeteufel (or other tracked minisub) that could launch itself.

but you almost don't need hindsight these problems were known at the time ...
 
In his book HITLER'S U-BOAT WAR: THE HUNTED 1942-1945 by Clay Blair Jr. he mentions sailing on a Type XXI postwar. He said it leaked like a sieve (they were built in sections and welded together in the yards). It was a good design but not sufficiently mature enough as a weapon system plus there were many quality control issues. I have no doubt the Type XXIII had similar problems...

that was (kinda) to my point, IF they had not rushed large Type XXI into production they could have concentrated on a more manageable sized Type XXIII which actually lends itself more to building in sections (as it was designed to be transported overland ... to Med, Black Sea)

Also design flaws - hydraulics were outside the pressure hull, which limited diving depth to c500ft.

books show approx. 600 ft. for Type XXIII vs. 400 ft. for early war Type II, both able to dive very quickly, not aware that these smaller types needed greater depth? the mini-submarines they attempted with exception of Seehund had problems diving, with expected results.
 
that was (kinda) to my point, IF they had not rushed large Type XXI into production they could have concentrated on a more manageable sized Type XXIII which actually lends itself more to building in sections (as it was designed to be transported overland ... to Med, Black Sea)

Given the huge problems Germany was facing at this point there simply wasn't time for proper testing or quality control, and any delays would have been unacceptable. They were lucky they got what they got.

And as I've said before in other threads sub crews are not easy to come by. Manning so many subs would be a real issue...
 
Given the huge problems Germany was facing at this point there simply wasn't time for proper testing or quality control, and any delays would have been unacceptable. They were lucky they got what they got.

And as I've said before in other threads sub crews are not easy to come by. Manning so many subs would be a real issue...

therefore building a type that required one quarter of the the crew of the alternative would be better idea?
 
Some other considerations, while the type XXI's were fabricated in far flung places, transported overland, and then assembled in the shipyards (with all the historical problems this entailed, what with many of the fabricated sections being built by folks that had no experience with shipbuilding), might not the type XXIII's, if focused upon earlier, have been able to avoid being built thus?
 
...books show approx. 600 ft. for Type XXIII vs. 400 ft. for early war Type II, both able to dive very quickly, not aware that these smaller types needed greater depth? the mini-submarines they attempted with exception of Seehund had problems diving, with expected results.
The figure of 500ft was taken from the Blair book cited by @eltf177, which I have somewhere or other. (Of course, with that much diversity of manufacture, transport, and assembly, then the finished articles would have varied quite a lot in characteristics).
 
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