Naval History Forums

Range of Ersatz Yorck and Mackensen?

Groner list the range of Mackensen at 8000@ 14knts , while the Yorck is 5500@ 14knts. Both ships have 90,000 shp mixed coal oil propulsion with the same storage capacity [4000tons coal and 2000 tons oil] The only real difference is the Yorcks are sligthly heavier at 38,000 tons vs 35,500 tons for the Mackensens.

So is just a typo or are the both 8000@ 14kts or more likely to be 5500@14kts. 8000 @ 14kts seems like a leap compared to previous models?

Forstmeier and Breyer (Deutsche Grosskampfschiffe 1915-1918) give the following cruising radius values for MACKENSEN and ERSATZ YORCK designs in their appendix of comparative ship/design statistics -

For 35431mt displacement (4000mt coal + 2000mt oil) = 6800 sea miles @ 13 knots <<<radius of action>>>


B

Byron Angel wrote:Forstmeier and Breyer (Deutsche Grosskampfschiffe 1915-1918) give the following cruising radius values for MACKENSEN and ERSATZ YORCK designs in their appendix of comparative ship/design statistics -

For 35431mt displacement (4000mt coal + 2000mt oil) = 6800 sea miles @ 13 knots <<<radius of action>>>


B

Radius of action means there and back again, suggesting the endurance at 13kts is 6800 x 2 = 13600 @ 13kts. Is that what they are suggesting ?

Paul L wrote: Radius of action means there and back again, suggesting the endurance at 13kts is 6800 x 2 = 13600 @ 13kts. Is that what they are suggesting ?

Dear Paul,

After a more careful examination and a more scrupulous translation of the text as given below, I'm not altogether positive that it represents radius of action, although the explanation of the date suggests that it may well do so.

The description of the relevant data column reads as follows -
"Die Fahrstrecke gemass Probefahrt bezieht sich auf den Brennstoffvorrat bei der Probefahrt (sog. Probefahrtverdrangung, in der Regel niedriger als die Konstructionsverdrangung). Die als >>Frontwert<< angegebene bzw. berechnete Fahrstrecke gibt die Strecke an, die das Schiff unter Berucksichtigung einer gewissen Gefechtsreserve zurucklegen kann. Beide Werte sind angegeben in sm/kn: Die Strecke in sm, die das Schiff bei einer bestimmten, gleichbleibenden Geschwindigkeit in kn zurucklegen kann."

- which I roughly translate as follows (subject, of course, to correction by any of our German speaking colleagues)-
"The distance determined by fuel level measurement under actual test voyage conditions (on the spot comparison of test voyage displacement, as a rule less than the standard construction displacement). They are given as actual combat values. For example, the cruising distance is specified as the distance which the ship can cover with an allowance for a certain battle reserve. The two values are given in sea miles and knots: the distance in sea miles which the ship can cover at a specified constant speed in knots."


B

Thanks Byron. It sounds like they are describing the range not the radius. As a matter of interest I compared the figure of 5500nm @ 14knots that Groner reports and compared that to other similar figures of similar ships. I got the expected range at 12knots to be ~ 8000nm. This makes the 13 knots expected range to be about 6750nm @ 13knots, not that different than the '6800 seamiles at 13 knots' that Forstmeier and Breyer report.

Die Fahrstrecke gemass Probefahrt bezieht sich auf den Brennstoffvorrat bei der Probefahrt (sog. Probefahrtverdrangung, in der Regel niedriger als die Konstructionsverdrangung).

Pay attention to the definition of displacement. "Probefahrtverdrängung" litterally means trial displacement, which is a good deal less than construction displacement, agains beeing a good deal lighter than full displacement with maximum buncerage.

MACKENSEN´s coal buncerage aacording to approved plans from 23th of may, 1914 was 2000t oil and 4000t coal (max). Construction displacement included 1100t coal, composed off 250t oil & 850t coal. This is quite a significant difference!

Regarding range, it´s perhaps of interest that Mackesen & co should recieve sets with geared cruise turbines on the two inner shafts with the outer shafts driven by direct drive turbines. Ers. Yorck should receive Föttinger hydraulic drives for all four shafts, which can be expected to increase the range significantly ove rthat of the previous DERFFLINGER´s / HINDENBURG´s.

delcyros wrote:
Regarding range, it´s perhaps of interest that Mackesen & co should recieve sets with geared cruise turbines on the two inner shafts with the outer shafts driven by direct drive turbines. Ers. Yorck should receive Föttinger hydraulic drives for all four shafts, which can be expected to increase the range significantly ove rthat of the previous DERFFLINGER´s / HINDENBURG´s.

So this sounds like the claim of 8000 @ 14kts does not seem like that much of a leap and could be possible?

Considering that the MOLTKE´s -with their less efficient hullform could go 4,120nm @ 14kts with 3,100t of fuels with direct drive turbines, I wouldn´t call 8000nm @ 14kts with reduction geared turbines on 6,000ts fuels an improvement...

Specific fuel consumption in forced power, 6 hour trial runs in VON DER TANN to SEYDLITZ ranged from a low of 0.654 kg/SHP to a high of 0.785kg/SHP. Note that these ships typically had direct drive setups. On the other hand, these trials were conducted under peacetime rules with the lighter trial displacement and Whelsh, high grade steaming coal.

SMS MOLTKE achieved an average of 27.85 kts at 76,795 SHP in her 6 hours trials and burned 45,2t coal and oil in the period. The buncerage was enough for 68 hours forced trial (in case the machinery could cope, which I don´t believe) and a corresponding theoretical range of close to 2000nm at 27 to 28kts.
Cruise range wasn´t much better, mosly due to the rapid increase in specific fuel consumption.

MOLTKE has a spec. fc of 0.667 kg/SHP at 76,795 SHP raising to 0.712 kg/SHP at 71,275 SHP and further to 0.828kg/SHP at close to rated power, 53,187 SHP.
Reduction gears greatly helped in limiting the raise in specific fuel consumption.

delcyros wrote:Considering that the MOLTKE´s -with their less efficient hullform could go 4,120nm @ 14kts with 3,100t of fuels with direct drive turbines, I wouldn´t call 8000nm @ 14kts with reduction geared turbines on 6,000ts fuels an improvement...

Specific fuel consumption in forced power, 6 hour trial runs in VON DER TANN to SEYDLITZ ranged from a low of 0.654 kg/SHP to a high of 0.785kg/SHP. Note that these ships typically had direct drive setups. On the other hand, these trials were conducted under peacetime rules with the lighter trial displacement and Whelsh, high grade steaming coal.

SMS MOLTKE achieved an average of 27.85 kts at 76,795 SHP in her 6 hours trials and burned 45,2t coal and oil in the period. The buncerage was enough for 68 hours forced trial (in case the machinery could cope, which I don´t believe) and a corresponding theoretical range of close to 2000nm at 27 to 28kts.
Cruise range wasn´t much better, mosly due to the rapid increase in specific fuel consumption.

MOLTKE has a spec. fc of 0.667 kg/SHP at 76,795 SHP raising to 0.712 kg/SHP at 71,275 SHP and further to 0.828kg/SHP at close to rated power, 53,187 SHP.
Reduction gears greatly helped in limiting the raise in specific fuel consumption.

..... Thanks for clarifying trial and standard tonnage, Delcyros. I was unable to find a suitable translation in any web dictionary for the respective tonnage/displacement terminology. May I assume that the rest of my translation was satisfactory?

B

It's perfect Byron.

Displacement definitions really are a mess in this period, particularely since trial displacements -at least in the HSF- changed with outbreak of the war towards a full load configuration (not overload). So we have to seperate between peacetime and wartime trial displacements. That - and the change of the measured mile range from the deep mile off Borkum to the two rather shallow miles in the Baltic are the principal reasons why trial speeds can be so different for peacetime and wartime trials.

In MACKENSEN's case all reported figures are guesstimates based upon peacetime data, or so I do understand the quotes.

Is this why German Battleships of this period dabled in installing a diesel engine on the mid shaft for cruise , while the outer shafts were Turbine shafts?
It looks like they could make 8000nm @ 12 kts on just 200 tons of diesel fuel. Can that be correct, or am I reading this wrong?

My reading is that the 200t of Diesel oil are for electrical power generation of the ship Diesels, not for main propulsion.

SMS SACHSEN´s construction displacement contains 900t fuel (500t coal + 400t Diesel oil). Deep load would be 4,000t (=2500t coal + 1500t Diesel oil).
The specific fuel consumption of the ship Diesel (Germania) is referenced with 0.215kg/hp (at most economical) to 0.235kg/hp (at max rating), installations from other manufacturers are reported to be more economical (particularely the machine proposed for PRINZREGENT LUITPOLDT).
We know that BADEN required 6,208 SHP at 28,500t in her dec. 19th trial to attain a speed of 12.451kts (in 34m deep water) so roughly 1.5t of Diesel fuel per hour would be required for SACHSEN at deep load to attain 12kts. If You assume that out of the 1500t fuel oil, roughly 200t are for the generators and another 300t for additional fuel injection of the coal boilers, then 1000t Diesel oil would be sufficient to achieve a range of 8000nm on Diesel engines alone.

The principal reason for Tirpitz to favour Diesel engines was the attempt to exploit of the technological lead of Germany in Diesel engines. It allowed roughly four times better fuel economy and was significantly cheaper for any installed SHP than coal/oil burning boilers, also required less manpower to operate these plants.
Tirpitz prevented a lucrative deal of MAN to sell licenses to Vickers because of his views that Diesel technology couldn´t easily be mirrored by the UK.

Thanks Delcyros!

Looking at some of the data in Groners volumes it looks like the diesels could be run along side the turbines to boost overall speed. It also looks like only some of these later BB had Diesels installed when the war ended. So I am assuming their top speed and endurance would have improved with the installation of such a diesel engine?

I have a more hypothetical question. How difficult would it have been to retro fit such diesel engines to the BattleCruiser line [Motkle , Sedlitz , Derfflinger etc etc? Perhaps the two mid shafts are run on Diesel for long cruise and the outer two shafts on Turbines driven by oil?

That is correct. Top speed and endurance were improved with Diesel engines. SMS SACHSEN´s rated design speed was 22.25 kts, which would translate to in between 24.0 and 25.0 kts trial under peacetime trial conditions.

I have a more hypothetical question. How difficult would it have been to retro fit such diesel engines to the BattleCruiser line [Motkle , Sedlitz , Derfflinger etc etc? Perhaps the two mid shafts are run on Diesel for long cruise and the outer two shafts on Turbines driven by oil?

I´m not sure that would have been possible at all. The problem with Diesel engines of the period was their significant installed height, which would break through the main armour deck at least in case of DERFFLINGER-class BC´s. The MACKENSEN´s didn´t had a sloped armour deck anymore and would have proved more flexible to this kind of change, atlough it would require major rebuildts. I consider this idea highly speculative.

I was considering their addaptablity to any kind of commerce raiding role . But thanks for that information. I noticed that the Diesel engine for the BB was about 12500hp and the four diesel engines for the Deutschland class PBC were also about 12-13,500 hp 15 years later. So was there not much development in Diesel engine design in the time between [1928-30 back to 1911-14] ?