Earlier Type XXI - informed by Cold War developments

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Re: Earlier Type XXI - informed by Cold War developments

Post by T. A. Gardner » 22 Jul 2020 20:28

Takao wrote:
22 Jul 2020 19:32
T. A. Gardner wrote:
22 Jul 2020 17:53
Don't forget the I 201 class submarines the Japanese operationally deployed...

https://en.wikipedia.org/wiki/I-201-class_submarine

One might note, that they were faster than a Type XXI at 20 knots submerged too.
To the best of my knowledge, the I-201 class and Ha-201 class were never operationally deployed. They had been completed and commissioned, but were still working up at the time of the surrender. Double checking their TROMs at combinedfleet.com makes no mention of them conducting war patrols.
The way I read it, both I 201 and 202 were sent on a patrol in early August 1944, days before the war ended to patrol off Vladivostok arriving on station on the 15th days after the war officially ended. They were recalled about a week later--there was some difficulty contacting them-- and they returned to Japan where both surrendered.

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Re: Earlier Type XXI - informed by Cold War developments

Post by Takao » 22 Jul 2020 21:17

TheMarcksPlan wrote:
22 Jul 2020 06:45
Some background info on the KM's view of Uboat warfare against Britain in the immediate run-up to WW2:
Absorbed in the grandiose Z Plan, the OKM emphatically
disagreed with Dönitz. The senior submarine planner at the OKM, Werner Fürbringer, a rear admiral and an assistant to Raeder’s chief
of staff, Otto Schniewind, framed the response. “At the present moment,” Fürbringer wrote, “U-boat blockade of England has very
little prospect of success for Germany. Any contradictory opinion, which takes comfort in the large number of our U-boats or in the
idea that the English U-boat defense will not be effective far out in
the Atlantic, can be dismissed as misleading” and, furthermore, it would be “irresponsible to commit the valuable U-boat crews” to
such a war. “It can be taken as proven,” Fürbringer went on, “that
every English convoy, no matter whether it operates along the coast
or on the high seas, will be secured by defensive forces, fully
capable of destroying with certainty any attacking U-boat, even
under the surface.” In support of has argument, Fürbringer stressed
the effectiveness of British sonar and predicted that the British would again resort to defensive mine3elds, which had been so
deadly effective against U-boats in World War I. Until U-boats
could be made “sonar-immune,” it was pointless to even consider
starting a U-boat campaign against British commerce.
From Blair's first volume...
You have absolutely no idea what Fürbringer is talking about do you?

Perhaps you would delve into Fürbringer's solutions to the foreseen "problem"?

And...
Otto Schniewind...The same Otto Schniewind, that on September 23, 1939, at a meeting at Hitler's HQ, called for an enlargement of the U-Boat program to building 20-30 boats a month, by giving it priority over other sections of the armed services. He also suggested that Russia & Italy be induced to build U-Boats for Germany? That Otto Schniewind?

The only real difference between Doenitz & the German Admiralty was that Doenitz wanted more(75%) Type VIIs, as opposed to the German Admiralty that wanted a more "balanced" U-Boat fleet of 1/3rd coastal, 1/3rd medium range, and 1/3rd long range submarines.


TheMarcksPlan wrote:
22 Jul 2020 06:45
...which again bears on the question of Raeder's pernicious influence on Hitler, who had previously criticized the Kaiser for attempting to challenge British predominance at surface sea warfare. Had the KM been restricted to the Uboot-waffe as its primary arm, such analyses as the foregoing would have rapidly found their way into the dustbin of history. The other alternative - no significant investment in the KM - would plainly have been abandoned.
Again, you are not getting "it".

The "solution" is not to focus entirely on the Uboatwaffe, as that allows the British to focus entirely on ASW ships. That is a self-defeating proposition. Germany gets to build some more U-Boats, but Britain gets to build a lot more ASW vessels and far earlier too. So, Germany is further in the "hole" than she would be historically.

Raeder's "solution" was to build a balanced fleet focused on commerce warfare...Why do you think all those Z-Plan warships had such a long range? Huh? Certainly not because they are going to duke it out with the British Home Fleet in the close by North Sea. You don't need incredibly long range to do that. Raeder's "solution" was a twin-pole strategy", where the submarines & surface raiders would do the most damage to British merchant shipping, and the surface fleet would create openings for the U-Boats & Raiders(as well as engaging in any offensive opportunities that presented themselves). It was a very good sound strategy for Germany.

However, Hitler started his war before Raeder was anywhere near ready to implement his naval strategy.
Last edited by Takao on 22 Jul 2020 21:42, edited 1 time in total.

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Re: Earlier Type XXI - informed by Cold War developments

Post by Takao » 22 Jul 2020 21:20

T. A. Gardner wrote:
22 Jul 2020 20:28
Takao wrote:
22 Jul 2020 19:32
T. A. Gardner wrote:
22 Jul 2020 17:53
Don't forget the I 201 class submarines the Japanese operationally deployed...

https://en.wikipedia.org/wiki/I-201-class_submarine

One might note, that they were faster than a Type XXI at 20 knots submerged too.
To the best of my knowledge, the I-201 class and Ha-201 class were never operationally deployed. They had been completed and commissioned, but were still working up at the time of the surrender. Double checking their TROMs at combinedfleet.com makes no mention of them conducting war patrols.
The way I read it, both I 201 and 202 were sent on a patrol in early August 1944, days before the war ended to patrol off Vladivostok arriving on station on the 15th days after the war officially ended. They were recalled about a week later--there was some difficulty contacting them-- and they returned to Japan where both surrendered.
Hard for I-201 & I-202 to go on patrol in August '44, when they were not completed until February '45.

Even if August '45...I have seen no mention in Wiki.

Double checked the Wiki and it says none were used operationally.

Checked Polmar & Carpenter's "Submarines of the Imperial Japanese Navy 1904-1945, and it also states that none were used operationally.

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Re: Earlier Type XXI - informed by Cold War developments

Post by TheMarcksPlan » 22 Jul 2020 22:47

Takao wrote:You get what's coming to you.
I've long ago realized that this poster is prone to hysteria and becoming unhinged in arguments - that's why I've ignored him for most of this thread.

Nonetheless, it is possible for even the most unhinged internet personas to flood a thread with disinformation. At a certain point it becomes necessary to correct them.

As a baseline for this discussion, note this quote:
Takao wrote:[The Z-plan] was a very good sound strategy for Germany.
Anybody who thinks the Z-plan was good strategy is disqualified to discuss WW2 naval strategy. That should be obvious.

Among other things, the Z-plan fleet would have required more fuel than the rest of the German economy. Pure lunacy.

Takao attempts to portray the Z-plan as appropriately invested in submarines because it provided for >200 subs by 1949. It should be obvious, once more, why this is sheer nonsense: As a capital ship cost ~50x a Uboot, submarines were an exceedingly small portion of the Z's planned expenditure.

That the planned big ships weren't intended for a Jutland redux, but for raiding operations, doesn't matter. The H-class and others would have met the same fate as Bismarck - wrecked by combined air/surface power.

I'll note that elsewhere Takao has probably voiced the sane opinion that the Z-plan was stupid. It is only because he has become unhinged in this argument that he now wants to pretend it was strategically wise.
Takao wrote:Sources:
Eberhard Rossler
"The U-Boat: The Evolution and Technical History of German Submarines"
Reference to forum rules on sources:
This requirement applies to each specific claim. In the past, some posters have attempted to evade the proof requirement by resort to the following tactics, none of which are acceptable here:

A general reference to a website, or a book without page references
We shouldn't trust amorphous book citations in general; this is especially true when dealing with an unhinged poster.

Takao has made many specific claims, he needs to provide pages and, preferably, direct quotations. I have so far provided probably 90% of the quotes in this thread.

--------------------------------------------------

On the general issue of the KM's prewar priority for submarines, the record could not be more clear: the KM neglected the Uboot Waffe.

From Rise of the Wehrmacht by Mitcham:
The
prevailing view in naval thought at that time, however, was that the
U-boat had already had its moment of glory during World War I, but
had been defeated. Even Heye wrote: ‘‘In an offensive war at sea one
should not expect too far-reaching results from U-boats alone,’’ because
British anti-submarine defenses ‘‘had reached an advance stage of
development. ... Generally speaking, U-boats operating as single units
cannot, due to their very nature be considered as an effective striking
force on the high seas.’’11
Captain Doenitz was never given a chance to air his views before the
Guse Committee, and the construction of a German fleet based primarily on the submarine was never seriously considered. Based on the

recommendations of the Guse Committee, Admiral Raeder presented
the Fuehrer with two alternatives: (1) construct a force consisting
mainly of pocket battleships, which could be ready fairly soon and
‘‘could in the event of war present a considerable threat to Britain’s
lifelines’’ or (2) construct a force consisting mainly of battleships, which
would take longer to build, but ‘‘could not only threaten Britain’s lifelines but also engage the British High Seas Fleet with every prospect of
success.’’ (According to his postwar memoirs, Raeder’s first alternative
suggested a force of ‘‘submarines and pocket battleships,’’ but the
records of the German Supreme Naval Staff do not support this
claim.)12 In any case, Raeder’s memorandum to Hitler was worded in
such a manner that he could have been in little doubt that Hitler, with
his passion for building large things—be they architectural designs,
public buildings, parades, or armed forces—would choose the alternative that offered the greatest glory to the German Reich. He was quite
correct: Hitler chose the battleship or ‘‘big ship’’ alternative, just as
Raeder, a ‘‘big ship’’ man, hoped he would.
p.161-2

Note that Takao appears uncritically to accept the "submarines and pocket battleships" line that Raeder offered post-war; perhaps that is what led him astray. One shouldn't trust Nazis.

-----------------------------------------------------------

While the KM's low opinion of submarine warfare is somewhat excusable given then-prevailing world opinion, it nonetheless raises the question of how the KM would have behaved had Hitler refused to invest in a large surface fleet. Recall that Hitler heavily criticized the Kaiser's Hochseeflotte.

I find it likely that the KM would have convinced itself of the submarine's utility had doing so been its only path to claiming more resources.
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Re: Earlier Type XXI - informed by Cold War developments

Post by Takao » 23 Jul 2020 00:56

TheMarcksPlan wrote:
22 Jul 2020 22:47
I've long ago realized that this poster is prone to hysteria and becoming unhinged in arguments - that's why I've ignored him for most of this thread.

Prone to hysteria and be coming unhinged in arguments...Like your kilometers long & millions of tons battleship or your idea to build a causeway across the English Channel? That kind of hysteria and unhinged arguments.


TheMarcksPlan wrote:
22 Jul 2020 22:47
Nonetheless, it is possible for even the most unhinged internet personas to flood a thread with disinformation. At a certain point it becomes necessary to correct them.
Yes, your flood of disinformation needs to be dammed, and levees need to be constructed to contain your disinformation into the smallest channel possible. So I do what I must, so I dam and levee.

As a baseline for this discussion, note this quote:

TheMarcksPlan wrote:
22 Jul 2020 22:47
Anybody who thinks the Z-plan was good strategy is disqualified to discuss WW2 naval strategy. That should be obvious.

Among other things, the Z-plan fleet would have required more fuel than the rest of the German economy. Pure lunacy.
The Z-Plan was meant for completion years in the future. Providing plenty of time for growth of Germany's petrochemical industry and the stockpiling of POL reserves.

TheMarcksPlan wrote:
22 Jul 2020 22:47
Takao attempts to portray the Z-plan as appropriately invested in submarines because it provided for >200 subs by 1949. It should be obvious, once more, why this is sheer nonsense: As a capital ship cost ~50x a Uboot, submarines were an exceedingly small portion of the Z's planned expenditure.
Seen this is the disinformation that needs damming...
It was 249 U-Boats by 1947(Rossler, 119)

The "sheer nonsense" is basing "appropriateness" on cost alone. That is sheer nonsense.

TheMarcksPlan wrote:
22 Jul 2020 22:47
That the planned big ships weren't intended for a Jutland redux, but for raiding operations, doesn't matter. The H-class and others would have met the same fate as Bismarck - wrecked by combined air/surface power.
More of Mr. Marcks' patented "sticking his head in the ground" ignorance...would the battleships have met the same fate acting in two mutually supporting carrier/battleship Task Forces...I don't think so.

TheMarcksPlan wrote:
22 Jul 2020 22:47
I'll note that elsewhere Takao has probably voiced the sane opinion that the Z-plan was stupid. It is only because he has become unhinged in this argument that he now wants to pretend it was strategically wise.
I don't think so...I have questioned the sanity of individuals that opined to building all U-Boats and no capital ships. I have questioned the sanity of individuals who opined to building all tanks and no Z-Plan.

Maybe back in 2011 or 2010 I did question the economics of Germany building a large Army, Navy, and Air Force.

But you are welcome to look if you are feeling that inadequate.



TheMarcksPlan wrote:
22 Jul 2020 22:47
Reference to forum rules on sources:
This requirement applies to each specific claim. In the past, some posters have attempted to evade the proof requirement by resort to the following tactics, none of which are acceptable here:

A general reference to a website, or a book without page references
We shouldn't trust amorphous book citations in general; this is especially true when dealing with an unhinged poster.
Hmmm....Hmmm....Hmmm.

Suddenly Mr. Marcks is now a "rules lawyer".
Preferring to hide behind "rules" rather than disproving my statements.

Anyone else wonder why Mr. Marks is now hiding behind rules instead of rebutting my statements?


TheMarcksPlan wrote:
22 Jul 2020 22:47
Takao has made many specific claims, he needs to provide pages and, preferably, direct quotations. I have so far provided probably 90% of the quotes in this thread.
Please state the claims you wished sourced.

FYI, you have misrepresented 90% of what you have sourced.

TheMarcksPlan wrote:
22 Jul 2020 22:47
On the general issue of the KM's prewar priority for submarines, the record could not be more clear: the KM neglected the Uboot Waffe.

From Rise of the Wehrmacht by Mitcham:
The
prevailing view in naval thought at that time, however, was that the
U-boat had already had its moment of glory during World War I, but
had been defeated. Even Heye wrote: ‘‘In an offensive war at sea one
should not expect too far-reaching results from U-boats alone,’’ because
British anti-submarine defenses ‘‘had reached an advance stage of
development. ... Generally speaking, U-boats operating as single units
cannot, due to their very nature be considered as an effective striking
force on the high seas.’’11
Captain Doenitz was never given a chance to air his views before the
Guse Committee, and the construction of a German fleet based primarily on the submarine was never seriously considered. Based on the

recommendations of the Guse Committee, Admiral Raeder presented
the Fuehrer with two alternatives: (1) construct a force consisting
mainly of pocket battleships, which could be ready fairly soon and
‘‘could in the event of war present a considerable threat to Britain’s
lifelines’’ or (2) construct a force consisting mainly of battleships, which
would take longer to build, but ‘‘could not only threaten Britain’s lifelines but also engage the British High Seas Fleet with every prospect of
success.’’ (According to his postwar memoirs, Raeder’s first alternative
suggested a force of ‘‘submarines and pocket battleships,’’ but the
records of the German Supreme Naval Staff do not support this
claim.)12 In any case, Raeder’s memorandum to Hitler was worded in
such a manner that he could have been in little doubt that Hitler, with
his passion for building large things—be they architectural designs,
public buildings, parades, or armed forces—would choose the alternative that offered the greatest glory to the German Reich. He was quite
correct: Hitler chose the battleship or ‘‘big ship’’ alternative, just as
Raeder, a ‘‘big ship’’ man, hoped he would.
p.161-2
Another grossly misrepresented quote.

Sigh, neither you nor the author have the foggiest of ideas as to what Raeder's strategy was. You might want to read "Raeder versus Wegener - Conflict in German Naval Strategy" in the Naval War College Review Volume 58 Number 4 Autumn.

TheMarcksPlan wrote:
22 Jul 2020 22:47
Note that Takao appears uncritically to accept the "submarines and pocket battleships" line that Raeder offered post-war; perhaps that is what led him astray. One shouldn't trust Nazis.
Not familiar with that line. What is the passage?

TheMarcksPlan wrote:
22 Jul 2020 22:47
While the KM's low opinion of submarine warfare is somewhat excusable given then-prevailing world opinion, it nonetheless raises the question of how the KM would have behaved had Hitler refused to invest in a large surface fleet. Recall that Hitler heavily criticized the Kaiser's Hochseeflotte.
I suggest you read all of Rossler's Chapter 4: U-Boat construction from 1935 to 1939, pages 102-121 to see how far off the mark this statement really is. Yes, the whole chapter.

TheMarcksPlan wrote:
22 Jul 2020 22:47
I find it likely that the KM would have convinced itself of the submarine's utility had doing so been its only path to claiming more resources.
Given your misrepresentation of Furbringer, I am not surprised.

Did you know he was a long time submariner?

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Re: Earlier Type XXI - informed by Cold War developments

Post by Takao » 23 Jul 2020 01:18

Mr. Marcks' also remains ignorant on how the British will react to this "No capital ships, U-Boat spam."

As always, a major failing of this What-If.

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Re: Earlier Type XXI - informed by Cold War developments

Post by T. A. Gardner » 23 Jul 2020 02:24

Takao wrote:
22 Jul 2020 21:20
T. A. Gardner wrote:
22 Jul 2020 20:28
Takao wrote:
22 Jul 2020 19:32
T. A. Gardner wrote:
22 Jul 2020 17:53
Don't forget the I 201 class submarines the Japanese operationally deployed...

https://en.wikipedia.org/wiki/I-201-class_submarine

One might note, that they were faster than a Type XXI at 20 knots submerged too.
To the best of my knowledge, the I-201 class and Ha-201 class were never operationally deployed. They had been completed and commissioned, but were still working up at the time of the surrender. Double checking their TROMs at combinedfleet.com makes no mention of them conducting war patrols.
The way I read it, both I 201 and 202 were sent on a patrol in early August 1944, days before the war ended to patrol off Vladivostok arriving on station on the 15th days after the war officially ended. They were recalled about a week later--there was some difficulty contacting them-- and they returned to Japan where both surrendered.
Hard for I-201 & I-202 to go on patrol in August '44, when they were not completed until February '45.

Even if August '45...I have seen no mention in Wiki.

Double checked the Wiki and it says none were used operationally.

Checked Polmar & Carpenter's "Submarines of the Imperial Japanese Navy 1904-1945, and it also states that none were used operationally.
I clearly meant 45. 44 was a typo as I did specify "weeks before the war ended."

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Re: Earlier Type XXI - informed by Cold War developments

Post by Takao » 23 Jul 2020 02:58

T. A. Gardner wrote:
23 Jul 2020 02:24
I clearly meant 45. 44 was a typo as I did specify "weeks before the war ended."
I figured as much, but just wanted to be certain.

You see, towards the top of the page, in the paragraph below the Class Overview box & General Characteristics box, is this paragraph
They were one of the fastest submarine class built during World War II, second only to Walter Type XVII closed-cycle powered submarines. Twenty-three units were ordered from the Kure Navy Yard under the 1943 construction program. Due to the deteriorating war situation, only eight boats were laid down, and only three, numbered I-201, I-202 and I-203, were completed before the end of the war. None of them saw operational use.
Where in the Wiki did you find the reference?

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Re: Earlier Type XXI - informed by Cold War developments

Post by Takao » 23 Jul 2020 03:11

Never mind, the reference is in the I-202 Wiki page here.
https://en.m.wikipedia.org/wiki/Japanes ... rine_I-202
On 15 August the war ended with the surrender of Japan but two days later I-202 sailed with I-201, I-121, Ro-500 and one other submarine and deployed in a line 150 mi (240 km) off Vladivostok. The Sixth Fleet staff ordered them on several occasions to return to Maizuru, and on 22 August a staff officer flew into Maizuru to stress the importance of the order. The submarines finally returned to Maizuru on 24 August after destroying their radios and other equipment, and in October sailed to Sasebo where they and their sister ship I-203 were taken out of service on 30 November and handed over to the Occupation Forces.
Interesting! Gonna look into this more.

Thanks!

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Re: Earlier Type XXI - informed by Cold War developments

Post by paulrward » 23 Jul 2020 04:04

Hello All :

I have been following this thread since it's inception, and there were occasions when it was stated by several
posters that the Germans could NOT have built a Type XXI U boat earlier than they did. I did a little engineering/
reverse engineering, and, based on the technology available to Doenitz in 1937, he could indeed have built a better,
faster submarine.

First, let us look at the types the Germans DID build in WW2:
German ww2 Submarines.jpg
From these, we can see that the types the Germans built early in the war, from Type II to the Type X, were all of
similar technology level, with similar hull forms and a lot of interchangeable equipment. This made for easier
production, and an upgrade made to one type could be applied to other types.

Now, let us assume that, in 1937, someone had held a meeting with Walter about the hydrogen peroxide turbine,
with Doenitz in attendance, and at the end of the meeting, it was conceeded by all that the technology was too
advanced for that time frame. However, it was proposed that some of the elements of the hull design COULD be
put into production. It must be remembered that the German U-Boats were NOT submarines, they were
SUBMERSIBLE BOATS ! They had hulls that were optimized for surface cruising, and it was expected that they
would only submerge to carry out daylight attacks, or to evade enemy warships and aircraft.

Now, what if the thinking had turned to building a submarine with the technology of 1937, that would be optimized
for high speed underwater attacks, and would be built using the existing components of one of the in-production
or proposed production classes of U Boats, such at the Type X Minelayer.

The new U-Boat would have a shorter, bulkier hull for greater battery storage, enhanced streamlining for improved
underwater speed, and a minimum of 'clutter' that would interfere with it's underwater mission. In addition, as the Dutch were completing their work on the new O-20 type submarine, which was equipped with a snorkel, it would
only be obvious to the Germans, once they learned of this development through their spy networks, to apply it to
this new type of high speed underwater attack sub, allowing it to make run ins and night attacks under water while using it's snorkel. The Diesel engines would be standard types, all of the fittings ' off the shelf' as much as possible, and the only real engineering that would have to be done would be some hydrodynamic work in a test tank to optimize the hull shape. Now while it is obvious that, in 1937, the Germans would not have been able to build
a 17 knot underwater speed U Boat, they certainly, with enough battery power and a little streamlining, could have built a 15 knot boat that could maintain this speed for the better part of an hour. And this would be a dramatic improvement in tactical capability.

And here is what the new type of U Boat, which I have labeled ' Type XXI - 1937 ' would look like :
German ww2 Submarines - Type 21 1937.jpg

It can be seen that it would make use of the larger diameter hull of the Type X, but shortened and optimized for
high speed underwater attack. The Conning Tower is more like a ' Sail ', with only a few 20mm guns for air
defense, and a snorkel for underwater cruising and battery recharge. This sub would be shorter in range, and
have less endurance than a Type IX, but would be able to tactically combine with the Type VIIs and Type IXs. It
would also be less seaworthy while surfaced, but this could be compensated by having the boat do a shallow
submerge during rough weather to avoid the worst of the storms.

Imagine the effect of a combined attack on a convoy by a Wolfpack consisting of several Type IXs or VIIs, along
with two or three Type XXI-1937s. The standard types would deploy along the path of the oncoming convoy,
and attack from the front, while the Type XXI-1937s would deploy on the flanks of the convoy, racing in underwater
to make attacks on convoy escorts and other high value targets, which tended to be clustered in the center of
the convoy formation.

The high underwater speed of the Type XXI-1937 would allow it to attack destroyer escorts and corvettes from
astern, and, as sonar and hydrophone performance is severely degraded astern of an surface escort, the Type XXI-1937 might be able to pick off the occasional destroyer, making it's attack in the dead zone of the warship's screws.

After carrying out it's attack, the Type XXI-1937 would clear datum by running directly away from the convoy to
the rear, forcing the convoy escorts to choose whether to try to follow the retreating U boat, or to stay with their
convoy. After an hour or so, the Type XXI-1937 would then simply hoist the snorkel, and set out at 12-15 knots
to catch up with the convoy and coordinate another attack with the other U-boats. Wash, Rinse, and Repeat,
all the way to Britain....


These are just thoughts.

Respectfully :

Paul R Ward
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Re: Earlier Type XXI - informed by Cold War developments

Post by T. A. Gardner » 23 Jul 2020 04:31

Well, in 1939, the counter argument to a need for high underwater speed might be that the U-boat was better on the surface most of the time as it improved scouting for targets. The snorkel was a non-starter at that point being unavailable and even if it were, being considered impractical for use on a continued basis at sea.
The view might be that attacking on the surface whenever possible was the best choice in a no radar environment, radar being a largely unknown quantity in 1939. Add that German sonar in 1939 was less efficient than in 1944, and that reinforces the attack on the surface argument.

So, there's considerable reason the Germans might reject the need for a high speed submersible at the time.

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Re: Earlier Type XXI - informed by Cold War developments

Post by Lars » 23 Jul 2020 09:52

Excellent post Paul.

One question: The Rudeltaktik was surface night attacks. Does the "1937 XXI" do its job at night attacks?

Paul,
I think you would find the tread below very interesting. Stuffed with interesting thoughts and facts. Els discusses a 1942 electro VIIC and a 1944 electro VIIC. I refer to Johannes Rösslers discussion on a 1943 study to retrofit VIICs as "electro" VIICs. Els draws most of his inspiration from Rössler's discussion. Rössler concludes that it was "perhaps surprising" that the U-bootwaffe didn't go that way. I agree.

In hindsigt given the time pressure, in, say, November 1942 I would have voted for the sub-optimal solution to retrofit VIICs as "electro" boats instead of going for the perfedt solution of XXI. VIICs as "electro" u-boats would be fast, cheap and practical.

viewtopic.php?f=11&t=64873&hilit=bastar ... 5#p1373671

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Re: Earlier Type XXI - informed by Cold War developments

Post by Terry Duncan » 23 Jul 2020 14:59

paulrward wrote:
23 Jul 2020 04:04
Hello All :

I have been following this thread since it's inception, and there were occasions when it was stated by several
posters that the Germans could NOT have built a Type XXI U boat earlier than they did. I did a little engineering/
reverse engineering, and, based on the technology available to Doenitz in 1937, he could indeed have built a better,
faster submarine.

First, let us look at the types the Germans DID build in WW2:

German ww2 Submarines.jpg

From these, we can see that the types the Germans built early in the war, from Type II to the Type X, were all of
similar technology level, with similar hull forms and a lot of interchangeable equipment. This made for easier
production, and an upgrade made to one type could be applied to other types.

Now, let us assume that, in 1937, someone had held a meeting with Walter about the hydrogen peroxide turbine,
with Doenitz in attendance, and at the end of the meeting, it was conceeded by all that the technology was too
advanced for that time frame. However, it was proposed that some of the elements of the hull design COULD be
put into production. It must be remembered that the German U-Boats were NOT submarines, they were
SUBMERSIBLE BOATS ! They had hulls that were optimized for surface cruising, and it was expected that they
would only submerge to carry out daylight attacks, or to evade enemy warships and aircraft.

Now, what if the thinking had turned to building a submarine with the technology of 1937, that would be optimized
for high speed underwater attacks, and would be built using the existing components of one of the in-production
or proposed production classes of U Boats, such at the Type X Minelayer.

The new U-Boat would have a shorter, bulkier hull for greater battery storage, enhanced streamlining for improved
underwater speed, and a minimum of 'clutter' that would interfere with it's underwater mission. In addition, as the Dutch were completing their work on the new O-20 type submarine, which was equipped with a snorkel, it would
only be obvious to the Germans, once they learned of this development through their spy networks, to apply it to
this new type of high speed underwater attack sub, allowing it to make run ins and night attacks under water while using it's snorkel. The Diesel engines would be standard types, all of the fittings ' off the shelf' as much as possible, and the only real engineering that would have to be done would be some hydrodynamic work in a test tank to optimize the hull shape. Now while it is obvious that, in 1937, the Germans would not have been able to build
a 17 knot underwater speed U Boat, they certainly, with enough battery power and a little streamlining, could have built a 15 knot boat that could maintain this speed for the better part of an hour. And this would be a dramatic improvement in tactical capability.

And here is what the new type of U Boat, which I have labeled ' Type XXI - 1937 '

German ww2 Submarines - Type 21 1937.jpg


It can be seen that it would make use of the larger diameter hull of the Type X, but shortened and optimized for
high speed underwater attack. The Conning Tower is more like a ' Sail ', with only a few 20mm guns for air
defense, and a snorkel for underwater cruiser and battery recharge. This sub would be shorter in range, and
have less endurance than a Type IX, but would be able to tactically combine with the Type VIIs and Type IXs. It
would also be less seaworthy while surfaced, but this could be compensated by having the boat do a shallow
submerge during rough weather to avoid the worst of the storms.

Imagine the effect of a combined attack on a convoy by a Wolfpack consisting of several Type IXs or VIIs, along
with two or three Type XXI-1937s. The standard types would deploy along the path of the oncoming convoy,
and attack from the front, while the Type XXI-1937s would deploy on the flanks of the convoy, racing in underwater
to make attacks on convoy escorts and other high value targets, which tended to be clustered in the center of
the convoy formation.

The high underwater speed of the Type XXI-1937 would allow it to attack destroyer escorts and corvettes from
astern, and, as sonar and hydrophone performance is severely degraded astern of an surface escort, the Type XXI-1937 might be able to pick off the occasional destroyer, making it's attack in the dead zone of the warship's screws.

After carrying out it's attack, the Type XXI-1937 would clear datum by running directly away from the convoy to
the rear, forcing the convoy escorts to choose whether to try to follow the retreating U boat, or to stay with their
convoy. After an hour or so, the Type XXI-1937 would then simply hoist the snorkel, and set out at 12-15 knots
to catch up with the convoy and coordinate another attack with the other U-boats. Wash, Rinse, and Repeat,
all the way to Britain....


These are just thoughts.

Respectfully :

Paul R Ward
So, at the point that the Germans were designing the Type VIIC as the boat that most suited their needs, they suddenly decide that they want a lot of other attributes, some of which are of dubious value at the time, and others which are totally unknown inventions at the time. High submerged speed is useful in a short term as moving above a certain speed means the boat is moving blind, but for attacking itself it is not really of much use at all. The snorkel is unknown until the Germans seize The Netherlands so that isn't going to happen until 1940 at the earliest. At the point of going to war the deck gun is the main weapon of the U-boat, so removing that is going to really reduce the kills it can make. Also, Doenitz was pushing the 'wolfpack' idea at this time, and that required the boats working together in a group, which is not going to be possible while they operate underwater. Why this tactic will fail and require U-boats to work mostly submerged is not going to be apparent until war experience demonstrates it, and Doenitz is unlikely to abandon the tactic he has been working on since WWI is most unlikely.

The idea that aircraft would bridge the 'Atlantic Gap' is most unlikely in 1939, so U-boats on the surface makes perfect sense in 1939. To change the entire design philosophy is going to take years, and needs war experience, for the most part, so you are not likely to see anything before 1941 and most likely not before 1942 to even begin trying to put all these pieces together, and even then we have the rather appalling statistic that out of almost 120 Type XXIs assembled, only 4 were seaworthy.

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Re: Earlier Type XXI - informed by Cold War developments

Post by TheMarcksPlan » 23 Jul 2020 16:59

Terry Duncan wrote:High submerged speed is useful in a short term as moving above a certain speed means the boat is moving blind, but for attacking itself it is not really of much use at all.
Not true, high speed enables a sprint into attacking position and penetration of the escort screen.
paulrward wrote:Now, what if the thinking had turned to building a submarine with the technology of 1937, that would be optimized
for high speed underwater attacks,
It's interesting that the Type XII concept involved higher underwater speed. Anybody have details? The project never got to detailed design but it's indicative of German realization that underwater speed was desirable.
lars wrote:VIICs as "electro" u-boats would be fast, cheap and practical.
Interesting discussion, thanks.

First thought is that the '42 VIIC at 9kn would have greater survivability but would still be too slow - and have too little endurance - to approach most convoys submerged. Even a slow 7kn convoy has to come within a few miles of a submerged boat, while a fast 9kn convoy still has to run it over. That would seem to mean that airpower mostly negates its effectiveness around the same time as OTL, even if Uboat losses are lower.

For the '44 e-VIIC, it has very useful submerged speed but again there's the endurance issue. I don't see a figure for projected endurance at top speed but it's likely in the area of 10min based on projection from low-speed endurance.

The slightly greater endurance at low speed would have been very useful in the Bay of Biscay during '42-'43.
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Re: Earlier Type XXI - informed by Cold War developments

Post by TheMarcksPlan » 23 Jul 2020 17:38

Lars wrote:
22 Jul 2020 07:43

The idea of the elctroboat was from November 1942:

"The meeting would end up in disappointment if it was not 2 engineers, Schuerer and Broecking, who realized a very simple solution, utilizing the new Walter hull design. Instead of using the lower section for Perhydrol, the idea was to install additional batteries there. This would effectively triple the battery capacity of the boat. Initial calculations showed that the performance of the new concept is far better than of the conventional U-boat, although not as good as of the Walter one. This however fully satisfied Doenitz and the development went ahead. The only problem was that the displacement of the boat was around 1600 tons - and at that time smaller boats around 1000 tons were preferred as much easier too handle and more resistant to depth-charges."

https://uboat.net/technical/electroboats2.htm
This text from uboat.net is practically identical to that in Eberhard Rossler's The Type XXI: Anatomy of the Ship, pages 8-9.

Rossler adds,"In retrospect it appears strange that no one had thought of this earlier."

Upthread someone suggested that Rossler rebuts this development narrative and that the T21 wasn't conceived until 1943 - no page citations provided of course. Just another reminder why it's important to provide actual text, rather than one's interpretation/recollection of text.
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