Bismarck Speed

[dunmunro]

Which data do you mean?

Edit:

The trial protocols are primary sources, of course. The M.Dv.Nr. 847 is an official Kriegsmarine regulation. 75% Zuladung is mentioned in the protocols and specified in the M.Dv.Nr. 847. The draft measurements are also mentioned in the M.Dv. 847. There is a better description of the draft measurement in another document I own. But without unit and the zero-level it's just speculation anyway.

Bismarck's load:

23/10/40 = 5807 cu/m Fuel Oil and 448t Feed water = 68% load (Zuladung)
29/10/40 = 6285 cu/m FO and 327t FW = 75% load Zuladung)
-------------------------------------------
difference = 478 cu/m FO and -118t FW = 7% load
= 479 cu/m x .95 specific gravity = 454t + (-118)t FW = 337t = 7% load

337t = 7% load, therefore 100% load = 337t x 14.286 (100/7) = 4814t

Bismarck's empty weight as per inclining trials on 22/07/40 = 38840t so 75% load implies 3600t load and during inclining tests ship carried 3830t load for
a total displacement of 42670t (loading and empty weights varied slightly).

The load weight, therefore, implies a trials displacement of ~42500 tonnes.

FO and FW stores on 23/10/40 and 29/10/40 imply a trials displacement of ~44800 to ~45140 tonnes.

Coincidently, if we lookup Bismarck's speed here:
http://www.sfu.ca/~dmunro/Bismarck_power_curve.jpg
at an interpolated displacement of 44800 tons @ 150k SHP we get 30 knots, almost exactly, matching the 30.01 knots claimed.

[Herr Nilsson]

How much is 100% load?

[dunmunro]

How much is 100% load?

337t = 7% load, therefore 100% load = 337t x 14.286 (100/7) = 4814t

[Herr Nilsson]

Sorry, I meant displacement at 100% load.

[dunmunro]

Sorry, I meant displacement at 100% load.

I don't know what it was. But using the empty weight as per the inclining tests and adding load we get a displacement of ~42500 tonnes @ 68% load. Of course this doesn't fit with the liquid stores as report by the war diary, but adding the liquid stores to the empty weight, as per the inclining trials and adding a few hundred tons more for crew and light AA we get ~45000 tonnes.

Edit: Adding 45000 tonnes and 25% load = get ~46200 tonnes. 100% load added to the empty weight as per the inclining trial, implies ~43500 tonnes.

[Herr Nilsson]

Duncan,

You can't use the empty weight of the inclining trial . It's much to low. Bismarck wasn't completed. AFAIK about 1130 t of machinery, artillery and hull were still missing on that day.

Once again, 0% Zuladung means Bismarck is fully equipped, but without any liquid. So you also have to add ammunition, general equipment, artillery equipment, machinery equipment etc. (about 2700 t)

75 % Zuladung means that the ship has the same weight like it has in case of every liquid is aboard at a level of 75 % on a fully equipped ship. It doesn't mean 75 % of every single liquid was there in reality. In your calculation you also discounted every liquid which is not fuel oil and feed water. Up to 1500 t of other liquids (in case of fully equipped) have to be taken into account. At least we don't have to forget that they were possibly aboard.

[dunmunro]

Duncan,

You can't use the empty weight of the inclining trial . It's much to low. Bismarck wasn't completed. AFAIK about 1130 t of machinery, artillery and hull were still missing on that day.

Once again, 0% Zuladung means Bismarck is fully equipped, but without any liquid. So you also have to add ammunition, general equipment, artillery equipment, machinery equipment etc. (about 2700 t)

75 % Zuladung means that the ship has the same weight like it has in case of every liquid is aboard at a level of 75 % on a fully equipped ship. It doesn't mean 75 % of every single liquid was there in reality. In your calculation you also discounted every liquid which is not fuel oil and feed water. Up to 1500 t of other liquids (in case of fully equipped) have to be taken into account. At least we don't have to forget that they were possibly aboard.

Bismarck's actual displacement during her speed trials is unknown. I'm trying to get a feel for the minimum and maximum possible. It is quite possible that she ran trials with only a minimal ammo load, and minimal provisions for the crew.

The Baron mentions that Bismarck continued to run speed trials into November 1940, and that during one trial she achieved 30.8 knots. Looking at the war diary, the lightest loading that Bismarck had during the November trials was on:

12/11/40
4439cu/m Fuel
616 tonnes Feed Water = Minimum possible empty weight plus liquid stores = 43673 tonnes. Now we have to add to this whatever fixed additions were put on the ship since the inclining trials and whatever provisions were made for the crew, and then subtract whatever liquid stores were used prior to the trials. I think a displacement at the beginning of trial, on that day of 45000 tonnes is quite possible, and maybe 44800 tonnes during the trial. This would equal ~44100 tons, and it is possible that the displacement was less than this.

[Herr Nilsson]

It is quite possible that she ran trials with only a minimal ammo load, and minimal provisions for the crew.

Of course it's possible, but it's irrelevant. 75% Zuladung just means that the actual weight of a ship on consumption trials corresponds to the weight of a fully equipped ship with 75% of its liquids.

[Dave Saxton]

We do have documentation on the weights.

Leers schiff: 41,243 (mit oel und wasser in den maschinen und hilfsmachinenabschnitten)
+
Artillery munition, sperrwaffen munition, bersatzung, proviant, verbrauchsstoffe, trink und waschwasser=
standardverdraengung:43,646
+
1/2; the speisswasser, heizoel,treiboel, schmieroel, and flugzeug betriebsmittel=
konstructionverdraebgung:47,253

We must only decide if the leers schiff, standard displacement, or construction displacement, should be used as the baseline. The baseline is of course 0% of the load. 100% of the load will be the difference between the baseline and the full load displacement of 51,395. 75% of the load plus the baseline displacement gives us the displacement at 75% load.

If the baseline is leers schiff: the displacement at 75% load = 48857
"" Standard displacement:=49458
""Contruction displacement:=50360

Should we exclude non-liquid loads such as ammo?

[dunmunro]

We do have documentation on the weights.

Leers schiff: 41,243 (mit oel und wasser in den maschinen und hilfsmachinenabschnitten)
+
Artillery munition, sperrwaffen munition, bersatzung, proviant, verbrauchsstoffe, trink und waschwasser=
standardverdraengung:43,646
+
1/2; the speisswasser, heizoel,treiboel, schmieroel, and flugzeug betriebsmittel=
konstructionverdraebgung:47,253

We must only decide if the leers schiff, standard displacement, or construction displacement, should be used as the baseline. The baseline is of course 0% of the load. 100% of the load will be the difference between the baseline and the full load displacement of 51,395. 75% of the load plus the baseline displacement gives us the displacement at 75% load.

If the baseline is leers schiff: the displacement at 75% load = 48857
"" Standard displacement:=49458
""Contruction displacement:=50360

Should we exclude non-liquid loads such as ammo?

There is also a weight breakdown here:

http://www.bismarck-class.dk/technicall ... eight.html

showing a construction displacement of 45950 tonnes.

[Herr Nilsson]

@Duncan

The weight list on John’s website is “as planned”. You can find these weights it in the weight list for battleship “F” from February, 26th 1937.

@Dave

The weights you’ve mentioned are from a weight list from April 30th 1940.
The weights are:
Ship fully equipped without oil and water: 43356 t
Standard displacement: 43646 t
Construction displacement: 47253 t
Full load displacement: 51395 t
With Reserve fuel: 53165 t

There is another weight list from April 1st 1940 with identical figures and a weight for the empty ship: 40361 t.


Relevant are:
Ship fully equipped without oil and water: 43356 t =0% Zuladung
Full load displacement: 51395 t=100% Zuladung

[Dave Saxton]

.....Relevant are:
Ship fully equipped without oil and water: 43356 t =0% Zuladung
Full load displacement: 51395 t=100% Zuladung

In that case the displacement at 75% loading would be ~49385 metric tons.

[dunmunro]

Photo: 8 December 1940, the Bismarck returns up the Elbe to complete her yardwork at Blohm & Voss in Hamburg.

At the end of her trials, the ship was scheduled to return to Blohm & Voss in Hamburg so that the yard could give her the "finishing touches" it had not been able to complete by September. On 9 December 1940 the Bismarck was back in Hamburg.

[José M. Rico]

Another photo. Bismarck anchored in Kiel 24-28 September 1940 (a month before the Baltic speed trials).
Approx. draft: 10 meters.

[dunmunro]

09 December 1940
06 March 1941 Ship receives finishing touches.

06-08 March 1941 Leaves Hamburg, sails to Scheerhafen.

08 - 17 March 1941 Camouflage paint added. Supplies embarked (ammunition, fuel, water etc). Two Arado 196 floatplanes (T3 + DL, T3 + Mk) embarked.

Anatomy of the Ship - Bismarck, page 8, and there are entries in War Diary that correspond to this.