Fuel consumption Bismarck

[Thorsten Wahl]

additional Iowa and KGV class (howe)

seem the US ships show relatively better performance within part load (Teillastbereich)
(Charts doesnt consider varying quantities of fuel and different calorific valus of fuel)

[Herr Nilsson]

From my primary sources:

Range BS.jpg (79.45 KiB) Viewed 553 times

[dunmunro]

additional Iowa and KGV class (howe)

seem the US ships show relatively better performance within part load (Teillastbereich)
(Charts doesnt consider varying quantities of fuel and different calorific valus of fuel)

Where did you get the data for Howe?

Also your data for North Carolina included more fuel than she would have normally carried in a combat zone, since it degraded her TDS:

NOTE: Fueling beyond the radius oil capacity increases radius at the expense of resistance to underwater damage.
This table is made available to the commander as a supplement to table I for use when increased radius and
decreased resistance to underwater damage are factors in a decision.

not to mention her seakeeping.

Here's the calculated range for Howe (in black) using her late war, clean bottom temperate water fuel consumption figures with 3850 tons of fuel:



Early war, ( IE in May 1941) RN ships used a superior grade of lower viscosity fuel, that gave considerably better specific fuel consumption.

[dunmunro]

From my primary sources:

So this is the range in nm with one, two or 3 shafts in operation?

[Herr Nilsson]

Yes, for normal pressure and for 7700 cubic meter fuel.

[Thorsten Wahl]

Where did you get the data for Howe?

From the piece you posted at the ship model forum

[dunmunro]

Where did you get the data for Howe?

From the piece you posted at the ship model forum

OK, but you have to use the fuel consumption per hour figures, because the endurance numbers have a built in reserve.

[Thorsten Wahl]

Marc does the primary source has a document name and date?
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Charts doesnt consider varying quantities of fuel and different calorific valus of fuel)

Bismarck at 28 knots consumption per day 960m³=806 metric tons light fuel oil(density ~0,84metric tons/m³) = 793 standard tons
793/24=33 tons/hour (not corrected for calorific value - light fuel oil has a higher calorific value per ton +~8%)
so
35,64 tons/hour at 28 kn corrected for calorific value.

KGV
KGV at 27 knots 36 tons/hour

if my assumptions about density and calorific value are correct
Notes always welcome

[Herr Nilsson]

It's called:

"Fahrttabellen der Schlachtschiffe Bismarck und Tirpitz"
it's an appendix on an elaboration of Oberbaurat Krux about the wartime experiences with the battleship type Bismarck/Tirpitz. No date. The elaboration is writen after the destruction of Tirpitz.

[Thorsten Wahl]

as 7,700 m³ were approx 6,468 metric ton

s

this 6468 t almost exactly fits the

3226t+3226t =6452 t fuel oil mentioned in the weight calculation of Bismarck

it seems the 1009 t resp ~2000t Ölsonderzuladung was unconsidered in this calculation.

[dunmunro]

Marc does the primary source has a document name and date?
-----------------------------------------------------------------------------------------------------------------------

Charts doesnt consider varying quantities of fuel and different calorific valus of fuel)

Bismarck at 28 knots consumption per day 960m³=806 metric tons light fuel oil(density ~0,84metric tons/m³) = 793 standard tons
793/24=33 tons/hour (not corrected for calorific value - light fuel oil has a higher calorific value per ton +~8%)
so
35,64 tons/hour at 28 kn corrected for calorific value.

KGV
KGV at 27 knots 36 tons/hour

if my assumptions about density and calorific value are correct
Notes always welcome

s

It is difficult to draw exact comparisons because we need to compare at the same SHP. The data on Howe implies that 27 knots = 114000 SHP (remember that these are late war figures when Howe displaced ~45000 tons). Howe ran trials with 27.5 knots at 112,930 shp (114,496 mhp) at displacement of
42,530 tons (43,213 mt) acccording to D&G and that seems consistent with these results for Howe as well:

[Thorsten Wahl]

Howe ran trials with 27.5 knots at 112,930 shp (114,496 mhp

this figure is really interesting as Bismarcks(calculated) construction speed at construction shp (115,500 shp) was also 27,5 kn / 28 kn
(Akte Allgemeine Konstruktionsunterlagen Überwasserschiffe available at the Marinearchiv Freiburg)
displacement according Akte... seem 42.360 metric tons and 250 rpm
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some of the Howe date seem unclear as they gave different fuel consumptions for the same timeperiod and same shp

[Herr Nilsson]

this figure is really interesting as Bismarcks(calculated) construction speed at construction shp (115,500 shp) was also 27,5 kn / 28 kn
(Akte Allgemeine Konstruktionsunterlagen Überwasserschiffe available at the Marinearchiv Freiburg)
displacement according Akte... seem 42.360 metric tons and 250 rpm

If you refer to the document, you got from me a while ago, than it's not quite right. You will find it at my home. Only you got a digital copy and 3 other persons.

german ships use light fuel oil - density approx 0,82-0,86 metric tons per m³
so 7,700 m³ ~ 6,468 metric tons

That's not quite right. The density of fuel oil in Bismarck's weight calculation is 0.927. (I know only one exception in case of Bismarck with a density of 0.95.) "Treiböl" had a density of 0.85, but that was only used by the Diesel-engines. "Schmieröl" had a density of 0.92. Take a look at the M-Boot weight calculation. You can find it on page 11 of the document mentioned above. There you can see a K-Amt form with the standard densities. The same form you can find for an Gneisenau calculation on page 39 with the same densities.

[Thorsten Wahl]

thanks for the hints

Thorsten Wahl wrote:
this figure is really interesting as Bismarcks(calculated) construction speed at construction shp (115,500 shp) was also 27,5 kn / 28 kn
(Akte Allgemeine Konstruktionsunterlagen Überwasserschiffe available at the Marinearchiv Freiburg)
displacement according Akte... seem 42.360 metric tons and 250 rpm

Sorry seems I looked at the wrong column should be 4,000 tons more

german ships use light fuel oil - density approx 0,82-0,86 metric tons per m³
so 7,700 m³ ~ 6,468 metric tons

That's not quite right

using density 0,927 t/m³
fuel weight should be then
7,700 m³ ~ 7,138 t

[dunmunro]

Further on Howe and KGV class fuel consumption and power output:

Howe's fuel consumption versus SHP, implies that 27 knots = 114000shp and fuel consumption = 36 tons/hr. This gives us a specific fuel consumption of .7074

Maximum fuel flow in KGV is 6 tons/hr per boiler or 48 tons/hr. 48 tons /.7074 lb/shp/hr = 152,000shp.

Imagine my surprise when I looked at the KGV entry in the 1940 edition of Jane's Fighting Ships:

Machinery: Parsons geared turbines. 4 shafts. S.H.P.: 152,000 = over 30 knots.