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Re: 3-shaft propulsion

Posted: Mon Aug 05, 2019 4:18 pm
by Alberto Virtuani
Hello everybody,
Thorsten Wahl wrote: "Bismarcks machinery was more sturdy, the complete steam piping was much better shock protected."
Hi, Thorsten, thanks for your answer to my question.

From what you write, I understand that the power plants were the same in terms of boilers and turbines, just more resilient to shock, hterefore the output power should have been the same (theoretically).

Bye, Alberto

Re: 3-shaft propulsion

Posted: Mon Aug 05, 2019 4:32 pm
by marcelo_malara
calculated screw slippage
Bismarck class (12-13 %) based on 118 RPM at 15 knots and ~265-270 RPM at ~30 knots (Fahrtabellen and MeilenfahrtBismarck )compares well with the same figure of
Iowa class(12,5%) based on 87 RPM at 15 knots and 196 RPM at 30 knots (FTP 218 war Service fuel consumption of U.S. Naval Suface vessels BB 61 class) these numbers differ a bit from the "First of Class Standardisation Trials)
Hi Thorsten. I was thinking in terms of propulsive efficiency, ie ehp/shp, don´t have any number for this, but isn´t that relation bettered with lower rpm?

Regards

Re: 3-shaft propulsion

Posted: Mon Aug 05, 2019 7:12 pm
by dunmunro
marcelo_malara wrote:
Fri Aug 02, 2019 10:26 pm
Can you post those numbers from KGV?

Regards
KGV recorded .715 lb/shp during trials and 111700shp = 35.65 tons/hr.

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 12:43 am
by marcelo_malara

KGV recorded .715 lb/shp during trials and 111700shp = 35.65 tons/hr.
Thanks!

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 6:46 am
by Thorsten Wahl
Howe_endurance1.jpg
Howe_endurance1.jpg (33.78 KiB) Viewed 979 times

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 12:33 pm
by Herr Nilsson
Alberto Virtuani wrote:
Mon Aug 05, 2019 4:18 pm
Hello everybody,
Thorsten Wahl wrote: "Bismarcks machinery was more sturdy, the complete steam piping was much better shock protected."
Hi, Thorsten, thanks for your answer to my question.

From what you write, I understand that the power plants were the same in terms of boilers and turbines, just more resilient to shock, hterefore the output power should have been the same (theoretically).

Bye, Alberto
Scharnhorst's and Tirpitz' turbines were of similar design, but Bismarck's was very different.
According their manuals Scharnhorst and Tirpitz had a very similar (almost identical) steam consumption per SHP, but Tirpitz' turbines were operated with a significant higher pressure in front of their nozzle sets. Only at very high SHP values the steam pressure on Scharnhorst was increased to a similar or even higher level to boost the output. Obviously Tirpitz made more revolutions per SHP between 8,200 and 42,100 SHP (in regard of one turbine set).

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 5:19 pm
by Alberto Virtuani
Hello everybody,
Herr Nilsson wrote: "Scharnhorst's and Tirpitz' turbines were of similar design, but Bismarck's was very different."
Thanks, but apart from turbine design difference (that surely affected endurance), I could find no reliable confirmation about the different battleships (Scharnhorsts and Bimarcks) maximum power/correspondant speed.


Bye, Alberto

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 6:27 pm
by Herr Nilsson
What are you looking for exactly?

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 6:46 pm
by marcelo_malara
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

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 6:47 pm
by marcelo_malara
Thorsten Wahl wrote:
Tue Aug 06, 2019 6:46 am
Howe_endurance1.jpg
What book is this from?

Regards

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 7:07 pm
by dunmunro
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.

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 7:09 pm
by dunmunro
marcelo_malara wrote:
Tue Aug 06, 2019 6:47 pm
Thorsten Wahl wrote:
Tue Aug 06, 2019 6:46 am
Howe_endurance1.jpg
What book is this from?

Regards
British Battleships of World War two, by Raven and Roberts.

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 7:28 pm
by Byron Angel
dunmunro wrote:
Tue Aug 06, 2019 7:09 pm
marcelo_malara wrote:
Tue Aug 06, 2019 6:47 pm
Thorsten Wahl wrote:
Tue Aug 06, 2019 6:46 am
Howe_endurance1.jpg
What book is this from?

Regards
British Battleships of World War two, by Raven and Roberts.
- - -

Hi Thorsten,
[ 1 ] Were any displacement data provided in connection with the above-mentioned Howe endurance figures?

[ 2 ] If one already possessed Friedman's book on British BBs and Burt's updated book on British BBs, does the Raven and Roberts volume offer sufficient additional insights to justify procuring it in addition?

Byron

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 7:39 pm
by Thorsten Wahl
Herr Nilsson wrote:
Tue Aug 06, 2019 12:33 pm

Scharnhorst's and Tirpitz' turbines were of similar design, but Bismarck's was very different.
According their manuals Scharnhorst and Tirpitz had a very similar (almost identical) steam consumption per SHP
You meant the consumption drawings in Kriegserfahrungen...Oberbaurat Krux?

Power RPM ....steam consumption t/h


3 × 1.880 95..........30
3 × 4.660 122 .......57
3 × 10.050 160 ......108
3 × 16.000 190 ......165
3 × 25.800 220........ 255
3 × 32.000 235 .......321
3 × 42.100 253 .......417
3 × 48.000 270 ........492

R* 3 × 16.000 190 ...375
One boiler produces maximal 50 t steam per hour
Required fuel at this output 3,950 kg per hour.

Re: 3-shaft propulsion

Posted: Tue Aug 06, 2019 7:48 pm
by dunmunro
Byron Angel wrote:
Tue Aug 06, 2019 7:28 pm
dunmunro wrote:
Tue Aug 06, 2019 7:09 pm
marcelo_malara wrote:
Tue Aug 06, 2019 6:47 pm


What book is this from?

Regards
British Battleships of World War two, by Raven and Roberts.
- - -

Hi Thorsten,
[ 1 ] Were any displacement data provided in connection with the above-mentioned Howe endurance figures?

[ 2 ] If one already possessed Friedman's book on British BBs and Burt's updated book on British BBs, does the Raven and Roberts volume offer sufficient additional insights to justify procuring it in addition?

Byron
The data corresponds to full load displacement based upon trials reports in the text.

I think R&R would be the best single volume but maybe Friedman and Burt together cover most of the same ground.