Earlier Type XXI - informed by Cold War developments

[Lars]

Totally agree.

[Takao]

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.

More of Mr. Marcks hysterical theatrics...since he is unable to rebut any of my statements, he must resort to lies & dishonesty.

Shame on you Mr. Marcks

Page citation and text were provided.
viewtopic.php?p=2281688#p2281688

[Lars]

The submerged speed of an 1943-electro VIIC is 15.9 knots with els' retrofittings:

"All this was achievable through the existing Type VII Uboat as a retrofit package. In fact the original designs for the “Type I” Uboat in the early 1930s [pu111], was a Uboat with 8.5-9knots top submerged speed and submerged endurance of 160nm @ 4knots. While the Type VII prototype was design to get ~8.5 knots top speed submerged.

By adding saddle tanks to increase surface endurance from 4800 –6000 nm, they sacrificed ½ knot off top speed. To reduce crash dive time from to 20 seconds, twice as much flooding slit area had to be adopted, resulting in another drop in the top speed of ½ knot. So the war production Type VIIC Uboats had top submerged speed of only 7.6 knots and an endurance of 80nm@ 4knots.

Reversing both of these should raise the top submerged speed back to ~8.5 knots. Further removing the flak and deck guns along with all the railings should increase the top speed again by 7%, to 9.2 knots.

[1] Finally a variable pitch propeller matched up to the existing generator should increase the top speed by 50% to 13.8 knots.

[2] By 1943 all new Type VII could be produced with the upgraded generator putting out 580 hp instead of 375hp of the original generator. Combined this should further increase the top speed to 15.9 knots.

[3] Replacing the existing ammo bunker and the bottom row of reserve torpedos with battery space would more than double the Uboat endurance."

[Takao]

Totally agree.

You were given the page number & text from Rossler's book, yet you agree with Mr. Marks fabrication.

Care to explain yourself?

[Lars]

Consider it deleted. This is un-productive.

[Takao]

The submerged speed of an 1943-electro VIIC is 15.9 knots with els' retrofittings:

"All this was achievable through the existing Type VII Uboat as a retrofit package. In fact the original designs for the “Type I” Uboat in the early 1930s [pu111], was a Uboat with 8.5-9knots top submerged speed and submerged endurance of 160nm @ 4knots. While the Type VII prototype was design to get ~8.5 knots top speed submerged.

By adding saddle tanks to increase surface endurance from 4800 –6000 nm, they sacrificed ½ knot off top speed. To reduce crash dive time from to 20 seconds, twice as much flooding slit area had to be adopted, resulting in another drop in the top speed of ½ knot. So the war production Type VIIC Uboats had top submerged speed of only 7.6 knots and an endurance of 80nm@ 4knots.

Reversing both of these should raise the top submerged speed back to ~8.5 knots. Further removing the flak and deck guns along with all the railings should increase the top speed again by 7%, to 9.2 knots.

[1] Finally a variable pitch propeller matched up to the existing generator should increase the top speed by 50% to 13.8 knots.

[2] By 1943 all new Type VII could be produced with the upgraded generator putting out 580 hp instead of 375hp of the original generator. Combined this should further increase the top speed to 15.9 knots.

[3] Replacing the existing ammo bunker and the bottom row of reserve torpedos with battery space would more than double the Uboat endurance."

Essentially, do to the Type VII what the British did to the HMS Seraph...But do it 5,6,7, or 8 years earlier.

Not very imaginative or groundbreaking, and likewise just as good - after about 20 minutes her battery is dead and she is sunk.

[Takao]

Consider it deleted. This is un-productive.

Yes it is. I have come to expect as much from Mr. Marcks, not from others.

[paulrward]

Hello All :

Mr. T.A.Gardner stated :

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.

Mr. Terry Duncan stated :

So, at the point ..... 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......
The Snorkel is unknown until the Germans seize The Netherlands so that isn't going to
happen until 1940 at the earliest.

OK, guys, I get it. The Germans are a dull, stolid, unimaginative people, made even more so by their rigid practice
of early toilet training. They never come up with new ideas, they have no flashes of intuition, there is zero initiative in their armed forces or their government, and they could never, EVER defeat the Allies.

First of all, the Snorkel was NOT unnavailable. The Americans had tested them prior to WW1, the British patented
it in 1916, the Italians tested a submarine with one in the early 1930s, and the Dutch were building a class of subs
with Snorkels in the late 1930s. Guys, if the Germans had their heads so far up it in 1939 that they didn't know
about Snorkels, then how the hell did they defeat France and bring Britain to it's knees in 1940 ? Remember who had
the first air force to field a Jet Fighter, a Rocket Fighter, a Pulse Jet Cruise Missile, and a Short Range Ballistic Rocket, all in the space of one year !

All it takes is one, brief, blinding flash of intellect :

Gary Larson Sharks

Larson Sharks.jpg (103.14 KiB) Viewed 458 times

Now guys, what if Doenitz, in 1937, gets on the phone to Admiral Canaris, and says, " Dude, send a couple of spies
into Holland and see what they are doing in terms of Submarine development " Canaris complies, two agents
travel all the way around the world, end up in Holland, and three months later, after a little folding money
changes hands with a couple of underpaid Dutch draghtsman, Doenitz has in his hot little greedys a full set of the blueprints for the new O-20 submarine.

The Germans take one look at the design for the Snorkel, say, " Hey, that's a wunderbar idea, but WE can make it
even better! We will put a streamline casing around it, reinforced and braced so that it can handle 17 knots of
speed through the water, add a few valves, make it extendable, and, Gott in Himmel ! have we got a great idea !"


In my design, the only things ' new ' in the design are the more streamlined hull, the streamlined North Atlantic Sail
type of conning tower, and the use of more batteries. You wouldn't even have to use the denser batteries of the
Type XXI, as they weren't available in 1937. The old fashioned, plain jane batteries used on the Type IXs ( just a
lot more of them ! ) would be sufficient. Use the same two diesels you put in the Type X. ALL the other equipment
is right off the shelf. Nothing new except some hydrodynamic streamlining, and the Snorkel, which you steal from
the Dutch.

Mr. Terry Duncan stated :

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

C'mon, Mr. Duncan, we are talking about the Germans here, NOT THE BRITISH ! If the Germans are so dull witted,
then how was it that they were capable of beating the British like a Government Mule for two years until the United
States stepped in and won the war ? All it would take would be Doenitz watching a group of swimmers running out
of the water at a Baltic seaside resort, seeing the shark fin in the surf, and having that flash of intuition, " Hey,
that's just vat vould happen to one of mine U-boats ! I vill haff to doo sumtink about that....."

And the Type XXI-1937 is born.....


Now, the design I came up with is NOT INCAPABLE of surface operations, with the caveat that it would have
no deck guns. The USN's GUPPY III subs were fully capable of surface cruising, and in fact often did so. They
would spend a lot of time on the surface, running on two diesels while the third kept the batteries topped of, and
with their snorkels, they could do the same under water, two diesels driving and one charging. A Type XXI-1937,
with same engineering plant as the Type X ( two supercharged GW F46a9pu nine cylinder, four-stroke diesel engines,
(4,700 bhp) and two AEG GU720/8-287 electric motors, (1,100 shp ) would in fact be faster on the surface than
under water. The difference is, with the greater battery capacity, it could run faster and longer under water on
it's batteries. And, with the Snorkel, it could run underwater all day, with the conning tower just barely awash,
the snorkel at full height, using one diesel to drive the boat and the other to top up the batteries. If aircraft are
sighted, you dive the boat, shut down the diesels, retract the snorkel, and go electric until flyboy gets bored and
goes home.

The true advantage conferred by the Type XXI-1937 is it's ability to combine tactically with Type VIIs and Type IXs
in combined Wolf Pack operations. It is, in effect, a force multiplier. While the Type XXI-1937 engages the convoy
escorts, relying on it's high speed and under water cruise ability, it can draw off the convoy screen, allowing the
'submersible boats' to engage and sink more members of the convoy, either underwater or on the surface.


In answer to Mr. Lars' question :

The same would apply at night, only more so. Imagine it is early 1940, and you are a destroyer captain, trying to
locate a fast moving streamlined electroboat that can run in and out of your convoy at 15 knots, in the dark and
possibly with a sea running. Not a good tactical situation.

The Type XXI-1937 makes an underwater attack, and exits the convoy to the rear. It drops back about five miles,
puts up the Snorkel, and follows the convoy, driving and charging at the same time. Four hours later, batteries
fully charged, the Type XXI-1937 stops charging, and submerged with Snorkel up, increases speed to 15 knots,
running on both diesels. Two hours later, it nears the convoy, shuts down the diesels, goes on batteries, and makes another underwater attack at 15 knots. If you can do this twice a night, after two of three nights, the only thing stopping you is an overwhelming sense of pity. ( It's a pity I've run out of Targets / Torpedoes.....)

I hope that this has addressed some questions.

Respectfully :

Paul R. Ward

[TheMarcksPlan]

[3] Replacing the existing ammo bunker and the bottom row of reserve torpedos with battery space would more than double the Uboat endurance.

So doubling the following endurance?:

war production Type VIIC Uboats had top submerged speed of only 7.6 knots and an endurance of 80nm@ 4knots

...which would give 160nm @4kn or 40hrs endurance.

Endurance varies inversely with approximately the cube of speed, so at 15.9kn the e-VIIC '44 would have ~40min endurance.

That's better than I initially thought, if my rough calculation is in the ballpark. Interesting idea.

[Lars]

>After about 20 minutes her battery is dead.

Do you have a source for this?

[Takao]

>After about 20 minutes her battery is dead.

Do you have a source for this?

http://rnsubs.co.uk/articles/developmen ... rials.html

[Takao]

Paul, you do realize that above 6 knots you snap of the snort, the boat floods and is lost.

The Germans were working on a 10 knot snort, but it was not finished before the war ended.

[TheMarcksPlan]

I regret having to engage further but the issue of when the Germans conceived the T21 is a pretty important point.

Takao claims is wasn't until 1943 and offers this quote from Rossler (The Uboat?), p.208:

After the final design of the Type XVIII had been presented to the 'K' Office, it became evident that, because of the extensive Walter-installation and large Aurol supply, the electric installation would have to be small. Consequently, once a goat's Aurol had been expended, it's submerged performance would be poor. In March, 1943, therefore, the Walter specialist, Heep, suggested that Broeking's reviewing officer, Naval Construction Director Oelfken, examine the possibility of using the very elegant shape of the Type XVIII in an advantageous manner with conventional propulsion means. His investigations showed a possibility of trembling battery capacity over existing U-Boats by enlarging the pressure hull downwards, to give an 8-shaped cross-section extending for approximately a third of the board's length. This would give significantly higher submerged speed and a greater submerged range. During a discussion with 'K' Office concerning the Type XVIII, her stated: 'If we intend to build such a large boat and have so much space at our disposal, we can accomplish much more than hitherto by using conventional engine installations. Furthermore, if the submerged properties are considered to be more important than surface properties, then we shall naturally make use of conventional propulsion methods in ways different from those we have used in the past.'

In Rossler's Type XXI book, however, he states the following on p.8-9:

That November meeting would have ended on a disappointing note for the U-Boat arm had it not been for two submarine engineers named Schuerer and Broecking. Listening to Walter's lecture, they came up with a simpler solution to Doenitz' problem. If the Admiral wanted higher underwater speed and longer ranges, why not just add another hull full of batteries underneath an ordinary submarine? The additional electrical capacity should provide the necessary power to meet requirements. A quick calculation showed the suggestions was [sic] indeed feasible. Thus at a stroke pre-World War I technology was adapted to the concept of the electro-submarine, which later became U-Boat Type XXI. In retrospect it appears strange that no one had thought of this earlier.

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

The first quote doesn't necessarily contradict the second. It's entirely possible - even likely - that multiple people thought of the obvious when looking at the Walter boat. Heers Heep and Oelfikon may have instigated research into an electroboat without knowing that Brocking and Shuerer had already done so. Bureaucratic replication, non-communication, and inefficiency were a hallmark of the Nazi state.

Furthermore, Rossler's Type XXI book - first published in 1991 - probably involved more T21-specific research that undercovered more detailed information than contained in Rossler's The Uboat - first published in 1982.

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

At the risk of of dragging unproductive exchanges further, note that my reference to Takao's failure to provide page-cites regards Rossler's Type XXI book, which he specifically cited upthread. viewtopic.php?f=11&t=250425&start=45#p2281706

Had Takao actually read the T21 book, or had he been required to provide page cites to it, he would have discovered or revealed that Rossler's Type XXI contradicts Takao's assertions while amending Rossler's earlier assertions.

To the extent that I implied Takao had given ZERO page cites, I was wrong. He gave a quote from one of the five books he cited. As he is on my ignore list, I don't see his posts unless he responds to me and didn't read the Rossler quote from The Uboat. Apologies.

Nonetheless, we should provide page cites and/or quotes from all books we cite, not just one of five. As this discussion shows, textual analysis is always best.

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

In sum there can be no dispute that Rossler traces the T21's genesis to the November meeting that Lars and I have been citing.

Rossler also agrees with me and several others that it's odd, in retrospect, that the T21 didn't come sooner.

[TheMarcksPlan]

In sum there can be no dispute that Rossler traces the T21's genesis to the November meeting

The purpose of the meeting, IIRC, was to address technical solutions to the declining performance of U-boats, by tons-sunk per boat-sea-day. That worrying trend had been ongoing for a long time before November 1942:



The next questions:

• Who called the November meeting? IIRC it was Donitz but not sure.
• Why didn't this meeting occur until November '42? U-boat performance had been declining for years by then. Donitz had been forced in May '41 briefly to stop surface attacks.
• What do we know about the research apparatus of the KM (good sources?), and why did it take a lucky encounter between Schuerer/Broecking and Walter to produce a seemingly obvious idea?

[paulrward]

Hello All :

Mr. Takao stated :

Paul, you do realize that above 6 knots you snap of the snort,
the boat floods and is lost.

The Germans were working on a 10 knot snort, but it was not finished
before the war ended.

Mr. Takao apparently did NOT read my posting :

The Germans take one look at the design for the Snorkel, say, " Hey, that's a
wunderbar idea, but WE can make it even better! We will put a streamline casing
around it, reinforced and braced so that it can handle 17 knots of speed through
the water, add a few valves, make it extendable, and, Gott in Himmel ! have we
got a great idea !"

Mr. Takao, you seem to have a problem: You apparently cannot conceive of the idea that what happened
historically was NOT the only thing that could have happened. History is fluid. Ideas, People, Events, all
COULD have occurred, NOT as they occurred historically, but in a different fashion.


The arrow that slew King Harold at Hastings might have missed, and William of Normandy would be known
to history as William the Bastard.

Columbus might have run into a late hurricane, and never been seen again, leading to further development
of New World Native Civilizations on both the North and South Continents.

Washington might have slipped off the bow of the rowboat crossing the Delaware, the I would be living in a
colony of Great Britain called New Hertfordshire......

And Hitler might have breathed too much mustard in WW1, and had his life saved and eyesight restored by a
German Army Medical Doctor who was Jewish, leading to a lifelong gratitude towards all German Jews....



After WW2, in just two years, the USN developed, tested, and began installing Snorkels on the USN's Gato,
Balao, and Tench submarines that was capable of allowing the sub to run at 15 knots underwater while charging.
( This I got from a retired USN officer, who stated that, since the last of the GUPPYs was out of service, it wasn't
that big of a secret anymore ! )

If the Germans had started work in the summer of 1937, I am pretty certain that they could have at least equalled
the USN's efforts at building a High Speed Snorkel, and done so in less than a year. Hydrodynamics is just physics,
and like all engineering problems, all you have to do to solve it is throw money and steel at it. At the same time,
they work out the outer hull and conning tower design, fine tune the pressure hull and battery layouts, and spend
a little time on the wargaming floor developing a tactical doctrine to use high speed underwater attack subs to
destroy British Convoys.


Mr. Takao, with just a few tweaks here and there, history, and the world we live in, would be much different......

Mare Crisium Soviet

Soviet Lunar Landing.jpg (59.27 KiB) Viewed 439 times

Respectfully :

Paul R. Ward