Bismarck Speed

Discussions about the history of the ship, technical details, etc.
delcyros
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Re: Bismarck Speed

Post by delcyros » Wed Jun 22, 2011 2:52 pm

But You agree that there is a difference between "erreicht" (=achieved) and "errechnet" (=calculated)?
The authors of this report had full access to trial data. More informations such as displacement and water depth of the trials are needed to attempt to reconstruct the speed/displacement functions of this ship but I take it from the report that a speed of 30.6 kts was achieved by BISMARCK even though the conditions remain unknown.

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Herr Nilsson
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Re: Bismarck Speed

Post by Herr Nilsson » Wed Jun 22, 2011 3:11 pm

delcyros wrote:But You agree that there is a difference between "erreicht" (=achieved) and "errechnet" (=calculated)?
Yes, I agree.
delcyros wrote:The authors of this report had full access to trial data. More informations such as displacement and water depth of the trials are needed to attempt to reconstruct the speed/displacement functions of this ship but I take it from the report that a speed of 30.6 kts was achieved by BISMARCK even though the conditions remain unknown.
The authors didn't even have access to the correct displacement data of Bismarck. :(
Maybe Bismarck achieved 30.6 kts, but we can't compare it to anything without additional data.
IMHO Bismarck was possibly able to run 30.1 kts at 150.000 SHP at 75% payload. It's just an educated guess, but I think anything more would need much more SHP.
Regards

Marc

delcyros
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Re: Bismarck Speed

Post by delcyros » Wed Jun 22, 2011 3:23 pm

I agree. It´s impossible to compare this with other data without further information.

delcyros
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Re: Bismarck Speed

Post by delcyros » Sun Jul 10, 2011 11:34 am

Aside from the reported trial speed of 28.374kts at ~117,000 SHP, are there any different speed / power data aviable for BISMARCK or TIRPITZ? I mean, from fuel consumption trials including as far as displacement was known...

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Herr Nilsson
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Re: Bismarck Speed

Post by Herr Nilsson » Fri Jul 15, 2011 8:41 am

Eureka! There's an original document of the EKK (Erprobungskommando Kriegsschiffneubauten) with a comparison of the speed/power curves of Tirpitz and Bismarck. It clearly states that Bismarck made 30.1 kts at 150,170 SHP and 75% payload.
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Marc

delcyros
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Re: Bismarck Speed

Post by delcyros » Fri Jul 15, 2011 1:58 pm

A great find, congratulations.

Do I have it to take that the document includes more speed figures than the top speed? If so -are there data´s aviable at lower speed, too?
And what is meant with 75% -a range in between 46,934 and 47,683ts, I guess?

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José M. Rico
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Re: Bismarck Speed

Post by José M. Rico » Fri Jul 15, 2011 2:23 pm

Herr Nilsson wrote:Eureka! There's an original document of the EKK (Erprobungskommando Kriegsschiffneubauten) with a comparison of the speed/power curves of Tirpitz and Bismarck. It clearly states that Bismarck made 30.1 kts at 150,170 SHP and 75% payload.
That has to be the data from the Meilenfahrten of 23 October 1940, I believe.

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Herr Nilsson
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Re: Bismarck Speed

Post by Herr Nilsson » Fri Jul 15, 2011 10:20 pm

@delcyros
There are two complete speed/power curves (each for one ship), starting from 7.5 kts and 2000 SHP up to 30+ kts. On these curves are markings (puncture with a small circles) for the speed/power pairs of values of the trial runs. There are only the 0% and 100%-weights of Tirpitz. Compared to that the weight of Bismarck would be 49385 mt at 75%.

@José
The last marking on the speed power curve of Bismarck is a bit more than 150,000 SHP. As we know there was a trial run with 150,170 SHP. Therefore my asumption was that it was this trial run.
Regards

Marc

alecsandros
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Re: Bismarck Speed

Post by alecsandros » Fri Jul 15, 2011 11:33 pm

@Herr Nilson:

Could you please tell us what was Tirpitz speed at 53000t ? (100% load)

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Re: Bismarck Speed

Post by dunmunro » Sat Jul 16, 2011 1:25 am

Herr Nilsson wrote:@delcyros
There are two complete speed/power curves (each for one ship), starting from 7.5 kts and 2000 SHP up to 30+ kts. On these curves are markings (puncture with a small circles) for the speed/power pairs of values of the trial runs. There are only the 0% and 100%-weights of Tirpitz. Compared to that the weight of Bismarck would be 49385 mt at 75%.

@José
The last marking on the speed power curve of Bismarck is a bit more than 150,000 SHP. As we know there was a trial run with 150,170 SHP. Therefore my asumption was that it was this trial run.
These loading weights are not well defined, and IMHO do not correspond to actual displacements, but are a percentage of design full load, which was considerably less than their actual full load values. I wonder how the power curve compares to my estimate:

Image

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José M. Rico
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Re: Bismarck Speed

Post by José M. Rico » Sat Jul 16, 2011 12:06 pm

dunmunro,
Bismarck was faster than KGV. Get over it.

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Herr Nilsson
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Re: Bismarck Speed

Post by Herr Nilsson » Sat Jul 16, 2011 3:18 pm

dunmunro wrote: These loading weights are not well defined, and IMHO do not correspond to actual displacements, but are a percentage of design full load, which was considerably less than their actual full load values.
I'm sorry Duncan, but the loading weights are well defined:
1.jpg
displacement without payload and 100% payload
1.jpg (94.77 KiB) Viewed 2446 times
The values for Bismarck according the weight list from April 30th 1940 are:
Displacement without payload: 43356 mt
Displacement with 100% payload: 51395 mt
2.jpg
75% payload
2.jpg (99.51 KiB) Viewed 2446 times
Regards

Marc

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Re: Bismarck Speed

Post by alecsandros » Sat Jul 16, 2011 5:37 pm

José M. Rico wrote:dunmunro,
Bismarck was faster than KGV. Get over it.
:clap:

dunmunro
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Re: Bismarck Speed

Post by dunmunro » Sat Jul 16, 2011 9:09 pm

There's still no proof of that... :negative:

delcyros
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Re: Bismarck Speed

Post by delcyros » Sun Jul 17, 2011 9:33 pm

@delcyros
There are two complete speed/power curves (each for one ship), starting from 7.5 kts and 2000 SHP up to 30+ kts. On these curves are markings (puncture with a small circles) for the speed/power pairs of values of the trial runs. There are only the 0% and 100%-weights of Tirpitz. Compared to that the weight of Bismarck would be 49385 mt at 75%.
With the 7.5 kts datapoint I was able to extrapolate the required speed to make 30.6 kts according to the MMF-model. The prediction for this speed is 161,500 SHP required but more datapoints would allow better model prediction. This may or may not be in within the powerplants capabilities for overload power (I don´t know).
The dataset from TIRPITZ with 100% runs would also allow to factor in displacement changes more precisely, namely to verify them with the KM set calculations.
Do You happen to know where exactly the measured mile was taken from? I guess from Pillau / Neukrug but which of the three ranges? The 25m, the 34m or the 65m range?

Thanks in advance,
delc

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