3-shaft propulsion

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

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marcelo_malara
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Re: Battleship Bismarck: A Design and Operational History

Post by marcelo_malara » Tue Jul 30, 2019 4:55 am

There are three items in the destroyer´s weights labeled machinery/auxiliary machinery in Whitley´s book, don´t know exactly what is each. For a proper comparison I would turn to battleship´s machinery.

According to Burt KGV´s machinery weighted 2700 t, for 110.000 hp at 400 psi (27 kg/cm2).

Garzke gives 2863 t for Scharnhorst (125000 hp at 52 kg/cm2) and 2756 t for Bismarck (135000 hp at 58 kg/cm2).

KGV: 40 hp/1 t of machinery

Sch: 43 hp/1 t of machinery

Bs: 48 hp/1 t of machinery


So, almost doubling the steam pressure gives between 10/20% of machinery weight saving.

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Re: Battleship Bismarck: A Design and Operational History

Post by Herr Nilsson » Tue Jul 30, 2019 7:38 am

marcelo_malara wrote:
Tue Jul 30, 2019 4:55 am
2756 t for Bismarck (135000 hp at 58 kg/cm2).
This is from the weight List M I (2800 tonnes at 115000 SHP norm. and 138000 SHP max.) from Dezember, 30th 1936 including 252.2 tonnes water and 32 tonnes of 2 spare propellers.
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Marc

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marcelo_malara
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Re: Battleship Bismarck: A Design and Operational History

Post by marcelo_malara » Tue Jul 30, 2019 4:05 pm

What is the meaning of M I? Is there an M II?

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Re: Battleship Bismarck: A Design and Operational History

Post by Herr Nilsson » Tue Jul 30, 2019 4:37 pm

M I is machinery in regard of propulsion (boilers, turbines etc. but also smoke stacks and piping). M II is auxiliary machinery (for capstans, rudders etc., but also the heating installation). M II was 1400 tonnes IIRC.
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Marc

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

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Alberto Virtuani
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Re: Battleship Bismarck: A Design and Operational History

Post by Alberto Virtuani » Tue Jul 30, 2019 4:51 pm

Hello everybody,
Marcelo Malara wrote: "Garzke gives 2863 t for Scharnhorst (125000 hp at 52 kg/cm2) and 2756 t for Bismarck (135000 hp at 58 kg/cm2)."
What was improved in Bismarck's boilers/machinery vs Scharnhorst's ?
Wasn't the Bismarck propulsion plant (including the boilers) basically the same as Scharnhorst's ?
Whitley mentions a pressure of 58 kg/cm2 @ 450° for Scharnhorst too...


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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marcelo_malara
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Re: Battleship Bismarck: A Design and Operational History

Post by marcelo_malara » Tue Jul 30, 2019 7:51 pm

Well, the working pressure seems higher.

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Re: Battleship Bismarck: A Design and Operational History

Post by marcelo_malara » Tue Jul 30, 2019 9:30 pm

Guys, I will open a new thread, I want to review some concepts of weights.

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Re: Battleship Bismarck: A Design and Operational History

Post by Byron Angel » Wed Jul 31, 2019 1:41 am

Be careful when comparing steam powerplant operating temperature specifications. I will venture that the 450deg temperature figure cited for German boilers was denominated in degrees Centigrade, equivalent to 800+ deg Farenheit.

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Re: Battleship Bismarck: A Design and Operational History

Post by marcelo_malara » Wed Jul 31, 2019 2:02 am

Yes, all German info is metric (°C and kg/cm2) and all USN and RN imperial (°F and PSI).
Whitley mentions a pressure of 58 kg/cm2 @ 450° for Scharnhorst too...
Yes Alberto, there are different values in the various sources, I think what you are mentioning is the safety valve pressure.

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Re: Battleship Bismarck: A Design and Operational History

Post by Alberto Virtuani » Wed Jul 31, 2019 3:34 pm

Hello everybody,

Hi Marcelo,
thanks, my questions were related to the fact that Whitley says that the power plants of Scharnhorsts and Bismarcks were the same and that they were working at the same pressure of 58 kg/cm2. Garzke & Dulin mention a different working pressure.
I have not found any indication that the two classes had different power plants, even if they were built by different manufacturers.

Does anybody have any German primary source to check these data and to see if and what improvement were put in place on Bismarck and then on Tirpitz to increase the output power ?


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: Battleship Bismarck: A Design and Operational History

Post by pasoleati » Wed Jul 31, 2019 3:39 pm

As far as I remember what Whitley says, even Scharnhorst and Gneisenau had slight differences in their machinery.

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3-shaft propulsion 3

Post by Alberto Virtuani » Wed Jul 31, 2019 5:04 pm

Hello everybody,
pasoleati wrote: "As far as I remember what Whitley says, even Scharnhorst and Gneisenau had slight differences in their machinery."
The manufacturer was different and the layout of the tubines/reduction gears was different, but the machinery was designed for the same output power.

Whitley says that the two Bismarcks had the same machinery as well. That's why I would be interested in understanding what was improved during the yeras to get a different output power (and possibly to prevent the machine problems that affected the twins, especially the Scharnhorst).


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: Battleship Bismarck: A Design and Operational History

Post by marcelo_malara » Wed Jul 31, 2019 6:45 pm

The only noticeably difference I found in Whitley´s is that the HP turbine in Scharnhorst was double-geared, whereas IP and LP were single-geared. In Bismarck all three were single-geared. This is not mentioned in Garzke´s.

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Re: Battleship Bismarck: A Design and Operational History

Post by Byron Angel » Thu Aug 01, 2019 1:52 am

For a good overview of the ins and outs of marine steam engineering in the WW2 era, go here -
https://babel.hathitrust.org/cgi/pt?id= ... =1up&seq=1

"Ships, Machinery and Mossbacks - The Autobiography of a Naval Engineer"
by Harold G Bowen, VAdm USN (Ret)

The author does a fine job explaining the evolution and intricacies of turbine and boiler technologies. I found this book most useful FWIW.

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Re: Battleship Bismarck: A Design and Operational History

Post by dunmunro » Thu Aug 01, 2019 2:28 am

marcelo_malara wrote:
Tue Jul 30, 2019 4:55 am
There are three items in the destroyer´s weights labeled machinery/auxiliary machinery in Whitley´s book, don´t know exactly what is each. For a proper comparison I would turn to battleship´s machinery.

According to Burt KGV´s machinery weighted 2700 t, for 110.000 hp at 400 psi (27 kg/cm2).

Garzke gives 2863 t for Scharnhorst (125000 hp at 52 kg/cm2) and 2756 t for Bismarck (135000 hp at 58 kg/cm2).

KGV: 40 hp/1 t of machinery

Sch: 43 hp/1 t of machinery

Bs: 48 hp/1 t of machinery


So, almost doubling the steam pressure gives between 10/20% of machinery weight saving.
Per Friedman, the Illustrious class carriers had 3 shaft machinery that had ~110k SHP output and weighed ~2450 tons.

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