3-shaft propulsion

Discussions about the history of the ship, technical details, etc.

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Byron Angel
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Re: 3-shaft propulsion

Post by Byron Angel » Wed Aug 07, 2019 8:47 pm

Dear pasoleati,
Wow ..... a great deal of fire and passion on your part. I'm just wondering why you are directing such ire toward Bill Jurens. Bill did not write the rules of the academic research game; all he has done is describe how they currently work. Without academic credentials connecting you to a suitable college or university, Private party research always faces obstacles. For example, see how much it will cost you to obtain article reprints from JSTOR without approaching them through a collegiate member library. Or try to obtain a copy of ship's plans from the NMM in Greenwich England. Money and restrictions rule the day.

B

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Re: 3-shaft propulsion

Post by Bill Jurens » Wed Aug 07, 2019 9:10 pm

I should make it clear at the outset, that at this point I am speaking on my own behalf, and not acting as moderator. I will insert commentary between asterisks...

Pasoleati wrote:

"Mr. Jurens's response flies against everything that solod historiography is. For example, the very basic foundation of the reference noting system in serious academic works is that every source must be open to checking by anyone so willing. I don't think any doctoral thesis could pass the bar if the aspirant kept his sources secret."

That might be true enough if I were advancing any claim or pursuing some sort of doctoral thesis. But I am not, and have in effect no 'thesis' to defend. A question was put forward asking why no CFD methodogy had been employed to determine Bismarck's resistance characteristics. I simply pointed out that there was no need to do so as the results of tank tests were already available. Simply having -- or having access to --something does not -- or at least should not -- carry with it the obligation provide copies, presumably free of charge, to any and all who might want to see it. In this case, I provided some useful information regarding the existence of certain documentation. Now I'm being vilified for doing so. The lesson, which many serious researchers have already learned many years ago, and one reason why so few tend to participate in forums like this, is that it is often better to simply keep one's mouth shut. How that promotes 'solid historiography' escapes me.

Pasoleati wrote:

"If there are archives that actually stipulate that any 3rd Reich era German material cannot be publicized, such archives should be closed down as what they do is stealing. I am quite certain that such archives/persons have not either conducted those tank tests or originally paid for them, so they have no genuine intellectual rights to them. In other words, they are making money on someone else's intellectual property. And that is stealing."

Except in some truly rare instances, the costs imposed and the restrictions regarding further distribution of information provided from public archives are not intended in any significant way to profit from anyone else's 'intellectual property'. When copies are made, you are not paying for the information IN the document as much as you are paying the costs of keeping the document safely in storage, retrieving it, duplicating it, and maintaining it in good condition over time. As an alternative, perhaps a document was purchased from a private collection. Does that then obligate the purchaser to thereafter provide free copies to everyone who might want one?

Pasoleati wrote:

"As for the claim that materials should be "interpreted properly" before giving access to it to all is akin to anti-gun gun grabbers who want to dictate who can bear arms and who cannot. In a free democratic society such attitude is unacceptable. Especially when the material concerned is something that presents absolutely no danger to anyone's security or privacy."

I hear what you are saying, but your commentary in this case is more political and ideological than technical in nature. Insofar as this forum is intended, I believe, to focus on technical issues, I won't pursue your comment further except to say that I feel it's somewhat overstated.

Bill Jurens

pasoleati
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Re: 3-shaft propulsion

Post by pasoleati » Thu Aug 08, 2019 4:18 am

Byron Angel wrote:
Wed Aug 07, 2019 8:47 pm
Dear pasoleati,
Wow ..... a great deal of fire and passion on your part. I'm just wondering why you are directing such ire toward Bill Jurens. Bill did not write the rules of the academic research game; all he has done is describe how they currently work. Without academic credentials connecting you to a suitable college or university, Private party research always faces obstacles. For example, see how much it will cost you to obtain article reprints from JSTOR without approaching them through a collegiate member library. Or try to obtain a copy of ship's plans from the NMM in Greenwich England. Money and restrictions rule the day.

B
Byron Angel, I have no particular axe to grind against Bill Jurens per se. But I got the impression from his first post regarding those tank test materials that someone is holding the material either out of pure spite or pure greed. Years ago I was provided a German aircraft related document for free. Some of my fellow enthusiasts asked for a copy and I provided them with a hard copy of it. I charged only the actual copying costs (10 cents per page) and actual postage. Some fellow enthusiasts have also requested occasional scans from a particular book (only a page or so at most, usually just a paragraph). I have simply taken a high-resolution digital photo and sent it. This provides a suitable copy for research at ZERO cost.

As for archives, public archives are taxpayer-funded institutions. In other words, the average Joe has already paid for the materials through taxes.

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Re: 3-shaft propulsion

Post by pasoleati » Thu Aug 08, 2019 4:25 am

Bill Jurens wrote:
Wed Aug 07, 2019 9:10 pm
As an alternative, perhaps a document was purchased from a private collection. Does that then obligate the purchaser to thereafter provide free copies to everyone who might want one?
Bill Jurens
How did the assumed private collector acquire the document? Again, as far as I know, any 3rd Reich official document in possession of a private collector has with 99 % certainty at some stage of its journey to that collector been stolen or obtained through illegal means such as looting. I believe acquiring stolen property is a felony.

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Re: 3-shaft propulsion

Post by Thorsten Wahl » Thu Aug 08, 2019 7:53 am

please dont derail this thread.
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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Re: 3-shaft propulsion

Post by Thorsten Wahl » Thu Aug 08, 2019 8:41 am

some data for Gneisenau
Gneisenau Fahrleistunga.jpg
Gneisenau Fahrleistunga.jpg (23.45 KiB) Viewed 315 times
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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Re: 3-shaft propulsion

Post by Thorsten Wahl » Fri Aug 09, 2019 12:27 pm

dunmunro wrote:
Tue Aug 06, 2019 7:07 pm
marcelo_malara wrote:
Tue Aug 06, 2019 6:46 pm
dunmunro wrote:
Mon Aug 05, 2019 7:12 pm

KGV recorded .715 lb/shp during trials and 111700shp = 35.65 tons/hr.
Just for the record, where is this data from?

Regards
The Design and Construction of British Warships, 1939-1945: The Official Records : Major Surface Warships by DK Brown.
Hello Duncan did DK Brown mentioned the heating value/ density of the used fuel oil
for instance the german fuel oil used to calculate german Fahrtabellen were based on a heating value of 8,800 kcal/liter - density 0,96 kg/Liter
the USN used a fuel oil with 150000 BTU/gal wich is 9,992 kcal/Liter density 0,966 kg/Liter
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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Alberto Virtuani
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Re: 3-shaft propulsion

Post by Alberto Virtuani » Fri Aug 09, 2019 4:31 pm

Hi Thorsten,
from what I read in your posted table (download/file.php?id=3574), it looks very unlikely that the twins could achieve the 32 knots (something around 190000 shp would be needed). Which displacement these data refer to for Gneisenau ? Sorry if my question is stupid but I don't speak German at all and possibly this info is already in the header of the table....

AFAIK, Scharnhorst achieved 32 knots at trials developing the 166500 shp in extra power (probably at a light displacement) but Gneisenau KTB reports 32 knots during the chase of HMS Glorious at operative displacement.....


Bye, Alberto
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)

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Re: 3-shaft propulsion

Post by dunmunro » Fri Aug 09, 2019 9:39 pm

Thorsten Wahl wrote:
Fri Aug 09, 2019 12:27 pm
dunmunro wrote:
Tue Aug 06, 2019 7:07 pm
marcelo_malara wrote:
Tue Aug 06, 2019 6:46 pm


Just for the record, where is this data from?

Regards
The Design and Construction of British Warships, 1939-1945: The Official Records : Major Surface Warships by DK Brown.
Hello Duncan did DK Brown mentioned the heating value/ density of the used fuel oil
for instance the german fuel oil used to calculate german Fahrtabellen were based on a heating value of 8,800 kcal/liter - density 0,96 kg/Liter
the USN used a fuel oil with 150000 BTU/gal wich is 9,992 kcal/Liter density 0,966 kg/Liter
The fuel type was not specified in the KGV trials but it was probably the pre-war Persian crude derived fuel with ~10K KCal/liter. However, AIUI, the KM used higher grade fuels for trials and for Atlantic operations, and that fuel was similar to USN fuel.

Post war trials of KM destroyers showed very poor specific fuel consumption.

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Re: 3-shaft propulsion

Post by marcelo_malara » Fri Aug 09, 2019 11:16 pm

Guys, how were the turbines arranged in WWI three shaft German´s battleships?

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Re: 3-shaft propulsion

Post by Byron Angel » Sat Aug 10, 2019 1:05 am

marcelo_malara wrote:
Fri Aug 09, 2019 11:16 pm
Guys, how were the turbines arranged in WWI three shaft German´s battleships?

Hi Marcelo,
Typically, three sets of turbines abreast, with each separated from its neighbor(s) by a longitudinal bulkhead. Additionally, each turbine set had its respective high and low pressure turbines in separate fore and aft compartments. All told, six compartments.

Byron

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Re: 3-shaft propulsion

Post by marcelo_malara » Sat Aug 10, 2019 1:28 am

Hi Byron.

So there was a HP turbine coupled to a LP one which in turn coupled to the shaft? All in the same line?

Regards

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Re: 3-shaft propulsion

Post by Byron Angel » Sat Aug 10, 2019 3:11 am

marcelo_malara wrote:
Sat Aug 10, 2019 1:28 am
Hi Byron.

So there was a HP turbine coupled to a LP one which in turn coupled to the shaft? All in the same line?

Regards

Hi Marcelo,
I cannot confirm that detail without more homework. The four shaft German BCs had two sets of machinery, with the high pressure turbines running the inner shafts and the low-pressure turbines running the outer shafts. I do not know what the set-up was in the three shaft BBs. I need to dig deeper in my references.

B

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Re: 3-shaft propulsion

Post by marcelo_malara » Sat Aug 10, 2019 3:40 am

The four shaft German BCs had two sets of machinery, with the high pressure turbines running the inner shafts and the low-pressure turbines running the outer shafts. I do not know what the set-up was in the three shaft BBs. I need to dig deeper in my references.
Yes, with two or four shafts it is easy, but three shafts complicate the arrangement. If you could find out anything it would be of great help. It would explain why three shafts were rare, at least before the introduction of gearing.

Thanks in advance!

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Re: 3-shaft propulsion

Post by Herr Nilsson » Sat Aug 10, 2019 10:49 am

From the original operation instructions (my collection):

SMS Kaiser:
Kaiser.jpg
Kaiser.jpg (126.85 KiB) Viewed 181 times
SMS Bayern (just two turbine rooms shown):
Bayern.jpg
Bayern.jpg (121.09 KiB) Viewed 181 times
In comparison:
SMS Moltke:
Moltke.jpg
Moltke.jpg (123.87 KiB) Viewed 181 times
Regards

Marc

"Thank God we blow up and sink more easily." (unknown officer from HMS Norfolk)

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