Fuel consumption Bismarck

Propulsion systems, machinery, turbines, boilers, propellers, fuel consumption, etc.
Thorsten Wahl
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Re: Fuel consumption Bismarck

Postby Thorsten Wahl » Sun Oct 21, 2012 7:43 pm

I created a chart baseed on the same amount of fuel (3667 tons) for Bis NC Howe and Iowa
based on ftp 218 for the US ships
korrigierte Fahrbereichstabellen Tirpitz nach längeren Borderfahrungen
Howe Data by Duncan

I dont know if the calorific values were the same
I also dont know if the ready status(additiona steam available for making more speed or more economical driving) of the ships were comparable
From the pure data the US ships seem very efficent in partial load range but apparantly loses this advantage at high speeds
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range on Basis 3667 tons of fuel.jpg
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Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

Bill Jurens
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Re: Fuel consumption Bismarck

Postby Bill Jurens » Sun Oct 21, 2012 8:33 pm

An interesting and informative graph.

All other issues aside, this presentation clearly illustrates the US design preference -- at least from c. 1930 on -- to design hulls for maximum efficiency at cruising speed rather than for maximum top speed. This is also reflected in USN destroyer designs, where the (much-advertised) maximum speeds steadily decreased from c. 1930 onward whilst the (much-less-well-advertised) cruising radius continued to improve. We have a really good article on this issue scheduled for an upcoming issue of Warship International. The fact that the Iowa class, which was faster than most contemporaries yet was actually nominalized for maximum cruising radius speaks volumes with respect to the qualities of USN engineering. The British were quite impressed with the South Dakota plant, although they did not very much like the rather large US engineering spaces. This problem was solved in the Montana class, never built, which had an arrangement similar to those used on USS Lexington/Saratoga and Midway. The Midway plant was derivitave of, but not nearly identical to, the Midway layout.

Bill Jurens.

Bill Jurens
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Re: Fuel consumption Bismarck (correction)

Postby Bill Jurens » Sun Oct 21, 2012 8:43 pm

The last line of my previous should, of course, say that the Midway class layout was derivitave of, but not identical to, the MONTANA layout...

Bill Jurens

Thorsten Wahl
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Re: Fuel consumption Bismarck

Postby Thorsten Wahl » Mon Oct 22, 2012 12:27 pm

as an extension to my prvious post i made a chart on the shaftefficiency for the mentioned ships
shaft rpm at 15 kn are 100% to get comparative figures (as shaft revolutions at 15 are 100% the full efficent shaft rpm for 30 knots should be 200%- the tighter - the better)
Data as mentioned
Howe data 6 month at moderate waters

especially the chart for SD and Iowa give indication for screws beeing optimised for a certain velocity range
whilst NC, Bis/Tir were roughly similar up to 24 knots

SD chart shows almost linearity in between 15kn to 21kn and Iowa having the most advantage at ~27 knots at additional shaft rpm versus additional speed

There are also interesting particularities you can derive from the charts
according ftp 218 iowa achieved 30 knots at 212000 hp and Bismarck required only ~150000 hp for the same speed.
one can say iowa had a larger displacment but its only half of the truth ftp 218 showing 2 speed/displacement figures ~56 kt displacement(i use in the above figures) velocity 30 knots and for 50 kt displacement 30,3 knots speed making the speed differency almost completeley disappear I would say.

the peculiarity I see is the following:
Tirpitz achieves the same velocity at somwhat lower displacement and noticably lower engine power but at higher fuel consumtion, this makes me nervous to a certain degree.
Attachments
Antriebseffizienz.JPG
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Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

dunmunro
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Re: Fuel consumption Bismarck

Postby dunmunro » Mon Oct 22, 2012 5:10 pm

Unfortunately, FTP 218 tends to underestimate Iowa class fuel consumption, as it shows fuel consumption lower than her trials figures:

http://www.dtic.mil/dtic/tr/fulltext/u2/a215701.pdf

Some other FTP 218 figures, such as the Essex class CVs shows unrealistically low fuel consumption.

Some figures of note are that Iowa made 29.7 knots with 170,960shp at ~56500 tons with a specific fuel consumption of .614lbs/shp, but much more data is available in the above article.

Thorsten Wahl
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Re: Fuel consumption Bismarck

Postby Thorsten Wahl » Thu Oct 25, 2012 9:19 am

from
http://www.bismarck-class.dk/technicall ... inery.html
see also
http://bismarck-class-forum.dk/thread.php?threadid=5453

Results of Dockyard Tests for Bismarck at a Displacement of 43,000 tonnes

Output (shp)----Shaft (rpm)------ Speed (knots)----Fuel consumption (gm/hp/hr)
3 x 46,000------ 265-------------------29---------------325
3 x 38,350-------250-------------------------------------320
3 x 23,300-------214-------------------------------------335=23.4 t/h vs Fahrttabellen approx 30,7 t/h
3 x 13,000-------176-------------------------------------370=14.4 t/h vs Fahrttabellen approx 20.6 t/h
3 x 8,300---------151------------------------------------415 = 10,33t /h vs Fahrttabellen approx 16,3 t/h
3 x 5,000---------128------------------------------------500 =7,5 t/h vs Fahrttabellen approx 13.7 t/h

comparing the dockyard tests from above and fuel consumption from "Fahrttabellen Schlachschiffe Bismarck und Tirpitz"
it became recognizable that ther is a relatively constant part of fuel consumption, which seems only time dependend and not dependend on speed from about ~6 tons per hour.
If I eleminate this constant consumption from the real life consumption I get a modified chart.
Apparantly this chart follows more closely the charts of the US ships than the "real life chart".

From the positioning of the US charts I conclude that the US consumption charts probably describe a load condition in between the ideal condition (Bismarck mod -6t/h-violet line) and Bismarck korrigierte Fahrbereichstabellen Tirpitz nach längeren Borderfahrungen(green line).
Attachments
Antriebseffizienz1.JPG
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Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

RobertsonN
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Re: Fuel consumption Bismarck

Postby RobertsonN » Thu Nov 08, 2012 9:00 pm

Just to say I appreciate people posting original documentation regarding trial speeds, ranges and displacements of various ships in this thread.

With regard to Thorsten's last post could it be that the normal operating condition in wartime was different in the KM from that in the USN? Namely, did a lone ship need to be in a higher state of readiness, involving significantly higher fuel consumption for the same speed, than a ship which was part of a balanced taskforce or a lone battleship with a strong cruiser/destroyer escort?

It seems that the RN was never very demanding regarding range, probably because of the British system of bases, and possibly in the later period by an underestimation of the fuel used by auxiliary machinery under wartime conditions.

The British ships appear to have been more competitive in speed, especially in the WW1 era. Roberts gives probably enough data for the Hood's trials at nominal deep displacement for an MMF graph. There is the complication that some of the figures are at 44600 tons displacement and others at 45000 tons but this difference does make the data look more authentic. The Hood achieved 31.9 knt at 44600 tons with 150220 shp (104.3% of nominal full power). As light ship was then 41125 tons and deep 46680 tons, 44600 tons was the 62.5% full condition. From what Delycros wrote earlier this would appear to have made the Hood the second fastest capital ship when new after the Richelieu, which benefitted from newer technology.

Of course, the Hood later gained weight, lost speed and could manage only a still respectable 28 knts in 1941. Just as there was a regretable failure to update her protection she retained her original machinery, with worn LP turbines, to the end.

The Repulse and Renown were also very fast ships. Parkes gives the Repulse as reaching 31.5 knts at deep displacement (no figure stated) at 119025 shp (106.3% of nominal maximum). Of course, they were poorly protected battlecruisers but were also handicapped by old tech machinery (large tube boilers and direct drive turbines). They were built in record time, which went some way to alleviating the battleship shortcoming of being up to date at the end of the design process but already unsatisfactory in some ways on completion. The Repulse gained much weight which much improved her protection but retained her original machinery, achieving 28.3 knt on trials in 1936 at 112400 shp, displacement not known.

Thorsten Wahl
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Re: Fuel consumption Bismarck

Postby Thorsten Wahl » Fri Nov 09, 2012 10:12 am

With regard to Thorsten's last post could it be that the normal operating condition in wartime was different in the KM from that in the USN? Namely, did a lone ship need to be in a higher state of readiness, involving significantly higher fuel consumption for the same speed, than a ship which was part of a balanced taskforce or a lone battleship with a strong cruiser/destroyer escort?


I made an regression analysis for the determination of constant fuel consumption from the FTP 218 and other data.
It appears for Iowa there is a constant consumption of about 2-2,5 tons per hour this seem the technical minimum to keep the ship operational

for Howe ther is a constant consumption in the order of 5 tons per hour
and for Bismarck the constant consumption is in the order of >7 tons per hour.

From description of the US data the fuel consumption from weapons systems running is completely neglected as well as additional steam for more speed.

As far as I know for Tirpitz it was required (according war diary) to maintain a continous less then 10 minutes readiness for weapons and steam for additonal speed and these figures were most likely included in the consumption / range data.
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

RobertsonN
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Re: Fuel consumption Bismarck

Postby RobertsonN » Mon Nov 12, 2012 8:41 pm

I would be interested to see endurance curves for these ships with a common auxiliary consumption (say 5 t/day) so that their relative propulsion efficiencies would be discernible. Of course, bigger ships would have somewhat higher auxiliary loads than smaller ones but assuming a constant value would be a start.

Thorsten Wahl
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Re: Fuel consumption Bismarck

Postby Thorsten Wahl » Tue Nov 13, 2012 6:49 am

seeing Bismarcks and also Howes consumption it appears to me that 5t/day auxiliary consumption seems more in the order of 5 t per hour +3t/h -1t/h
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: Fuel consumption Bismarck

Postby Thorsten Wahl » Wed Feb 17, 2016 10:43 am

some information on the used german fuel oils
fuel oil used prior to WW2
calorifc value 10000 kcal/l

fuel oil used during WW2
calorific value 8800 kcal/l

I would conclude: from a energetic point of view, the use of low-quality-fuel oil reduced the potential range of german ships by about 10-13%.

Edit: I would conclude:
Last edited by Thorsten Wahl on Wed Feb 17, 2016 12:03 pm, edited 1 time in total.
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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Herr Nilsson
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Re: Fuel consumption Bismarck

Postby Herr Nilsson » Wed Feb 17, 2016 11:04 am

Who says?
Regards

Marc

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Herr Nilsson
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Re: Fuel consumption Bismarck

Postby Herr Nilsson » Wed Mar 23, 2016 8:09 am

Thorsten,

no, there was no 10000 kcal/l and 8800 kcal/l fuel oil. The oil had usually a calorific value between 10000 and 8800 and both values were used as reference values. In reports the calorific value was converted into one of them for comparison purposes. Everything that dealt with operation radius was converted into 8800 kcal/l for example fuel consumption trial runs. 8800 kcal/l was considered as a worst case scenario. 10000 kcal/l was used for the annualy top speed trial run. Both reference values could be easily converted into each other, so it happened that fuel consumption trials were converted into 10000 kcal/l values to complete a diagram for example.
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Marc

Thorsten Wahl
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Re: Fuel consumption Bismarck

Postby Thorsten Wahl » Wed Jun 15, 2016 9:57 am

I derived my statement from
Comment K-Amt K III A.Nr 228/41 gkdos from 1 April 1941
regarding
"Denkschrift der Seekriegsleitung über Forderungen für den zukünftigen Kriegsschiffbau auf Grund der Erfahrungen des ersten Kriegsjahres bezüglich der Kriegsbrauchbarkeit unserer Kriegsschiffneubauten"; Neu 1.Abt. SKL 1492/41 gkdos 4. Februar 1941

"...Another reason for the decrease of ship-ranges is the deterioration of the fuel oils due to the difficulties of oil supply in the war."
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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Herr Nilsson
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Re: Fuel consumption Bismarck

Postby Herr Nilsson » Thu Jun 16, 2016 9:47 am

Thank you for clarification. The statement of K-Amt is right and no contradiction. I've seen calorific values of oil used by different ships in 1940 and all were over 9000 kcal/l (IIRC over 9200 :think: ).
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Marc


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