Redesigning Bismarck

[Thorsten Wahl]

Graf Spee
MDV 550 Heft 1, vorläufige Zusammenstellung über das Seegefecht vor dem La Plata am.13.12.1939
https://drive.google.com/file/d/0B12aaM ... HRqXpjp1kw

list of Damage is pretty unclear regarding fuel oil processing system. But it must be a hit near the funnel base as splinter perforated the funnel and cause fire hazard because of the diesel oil. But the holes could be plugged and welded shut fairly easy.

[Mostlyharmless]

My dim memory of other discussions is that a steam plant was destroyed which powered the oil separation plant.

[Bill Jurens]

Alan Zimm and I did a very comprehensive treatment of the damage to Graf Spee in Warship 2018. His part was a tactical analysis. My part, "Under the Guns" was a technical analysis of the damage.

Bill Jurens

[hans zurbriggen]

Hello Mr. Jurens,
would you mind to please share here a summary of your conclusions regarding damage to oil processing system ?

Which hit are we speaking about in relation to numbering/plans present in German report (https://drive.google.com/file/d/0B12aaM ... HRqXpjp1kw) ?
Do you agree with Mr. Wahl that this would have been relatively easy to fix (as it is not in irreparable damages list at pag.12 of same report) ?
BTW, what was the purpose of this system on board (any need to "prepare" oil for Diesel engines sounds odd to me) ?

Thanks in advance

hans

[Bill Jurens]

The best bet in this case would be to read a copy of my paper in Warship. My general sense of it is that this purified-oil problem has been somewhat over-emphasized. In reality, none of the damage details would have mattered very much; with the whole Royal Navy on the job, there was essentially no way that Graf Spee was going to make it back to Germany anyway, even if she had entered Montevideo in pristine condition. And she wasn't in pristine condition -- the trip back across the Atlantic would have been somewhat stressful even in peacetime, and probably would have demanded some sort of escort to help ensure a completely safe crossing.

Bill Jurens

[Bill Jurens]

Further to the earlier question, I am not sure exactly what might have been meant by the oil purification system either. It could be that Langsdorff felt that many fuel oil tanks had been contaminated with salt water due to leakages caused by near-misses during the action. The same might be said because the oil reserves might have contained a fair amount of particulate matter 'shaken-out' by various impacts and vibration. In any case, the filters just before the fuel injectors should have been able to handle that, although frequent cleaning might have been required. (In those days, cleaning was usually considered preferable to replacement).

The other alternative -- admittedly a bit bizarre -- is that the reference to "oil purifying" was not made with reference to the propulsion plant at all, but instead referred to the loss of ability to store and purify cooking oil. One projectile, at least, heavily damaged the galley. Sometimes 'reports' are made by those not entirely familiar with the technology involved, especially if it's 'dockyard gossip'...

Bill Jurens

[hans zurbriggen]

Hello Mr. Jurens,
thanks a lot for your answer and precious info. It's precisely my understanding, reading German damage report.

Regarding the chances to get back, however, I disagree: in 1941 Admiral Scheer got back to Germany after an even longer and more successful cruise, avoiding British patrols in the Denmark Strait, with longer daylight and without such a sharp radar superiority (at that time of war).
IMHO, key point is whether Admiral Graf Spee was actually compelled to enter a harbor for basic repairs (especially to bow hole, I think) or whether she could have tried to stay at sea, to shake off her pursuers (her range was superior, 75% of fuel was still available on board and ammunition was very low for British too), to hide in South Atlantic to fix what was possible to fix, and then to get back to Germany.
I suspect Langsdorff's wound had a weight in his decision. After all, her support ship Altmark was waiting South of Montevideo, for a rendez-vous before planned leave to Germany.

hans

[NCC1717]

The ships's lubricating oil might also have had a purification system.

[hans zurbriggen]

Hello Mr. NCC1717,
you are right, however at pag.12 of list of damages (https://drive.google.com/file/d/0B12aaM ... HRqXpjp1kw), no hit is mentioned to have penetrated the ship vitals, not even n.3. Lubricating oil purification system should have been placed in engine room or close to it, within vitals.
Such damage (as well as damage to any fuel oil purification system) would have been listed in damage list and it is not. Also, there is no mention to it in list of irreparable damages at pag.12 bottom.

hans

[wadinga]

Hi All,

To return to a redesigned Bismarck, Hans is, of course correct. A firm decision was indeed made to switch to completely diesel propulsion for the H class as laid down and, shortly after allocation of the first resources and work on the keel, to abandon construction completely.

M J Whitley in German Capital Ships of WW2 details the wrangling between the Marineaubildungsabteilung (AIV) development office and the Construction Office and Admiral Fuchs of the Fleet Office Flottenabteilung throughout 1937 and 1938 over armament, hull design and propulsion. The proposed Entwurf I design would have had 220,000shp from a mixed diesel and turbine power plant and was supported by the AIV, whereas the Entwurf IV had an all diesel installation for 165,000shp and was supported by the New Construction Committee. Then the Construction Office reported they considered neither design could deliver on the promised parameters of speed, armour and armament. Finally Raeder stepped in and made his decision, backing pretty much all of the Entwurf IV design in December 1938 and put Fuchs in charge of making it happen.

The first plates were laid down on 15th July 1939 at Blohm & Voss and work stopped on the 30th September, and the rusting remnants lay on the stocks until November 1941.

K & S in their various books on German warships make no secret of their personal enthusiasm for all-diesel powerplants, but also supply plenty of excuses why the installations in the Panzerschiffe and the light cruisers had so many problems. MAN were forced to keep their unit's weight down in order to "comply" with Washington limits and the engine beds were of inadequately light construction. A powerful lobby for the new high tech, high temperature high pressure steam installations almost resulted in Graf Spee getting such an installation instead of diesels according to Whiteley! Her revised and upgraded diesel installation was 497 tonnes heavier that Deutschland's. The need for more speed meant Scharnhorst and her sister got turbines but the HP/HT installations had their own problems in them, the Hippers and the Zerstroyer.

As Bill has rightly pointed out, diesels are quite pernickety about their fuel supply and water from condensation or debris or paint fragments can cause problems with the fuel injectors which must deliver precise quantities of atomised fuel for pressure-induced combustion in the cylinders to take place. The installed hybrid powerplants in the light cruisers had to have separate bunkers for the two types of fuel. A fuel purifier system, usually based on centrifugal principles is normal for marine diesels. Furnace fuel to heat boilers is far less critical in its consistency being sprayed into the burners and is lower down the refinement process, and ISTR the Japanese burned some crude in their ships (Taiho) straight from the well where necessary. I believe Graf Spee had boilers above the protective deck for domestic purposes and they may have had something to do with conditioning the diesel fuel through filtration and heating to achieve the correct purity and viscosity for reliable combustion. The report seems to be mainly concerned with structural damage and the consequence of the boiler damage may have been overlooked.

MAN might have complained about not getting Kriegsmarine funds to develop big diesels, but elsewhere firms managed just fine on civilian work. Doxford built 10,000shp units for the British liners Georgic and Britannic ( 2 each) at the beginning of the 30s and the later Italian Augustus had even bigger engines. However these big vessels only needed speed in the low 20 knot range, but for higher speeds steam reigned supreme in the North Atlantic. Two giant diesels (one per shaft in one hull was one thing but twelve with all the gearing and coupling arrangements was a big gamble.

Today's giant diesels have become absolutely enormous, eg Wärtsilä RT-flex96C delivering over 100,000shp.

All the best

wadinga

[hans zurbriggen]

Hello Mr. Wadinga,
re. Admiral Graf Spee (I agree this is out of topic and we should open another thread to discuss it) German damage report lists all damages that were not reparable, structural and to equipment at pag.12): no mention to auxiliary boiler (that was probably repaired at Montevideo, possibly being just a splinter damage to some pipes and not to boiler itself).

Regarding Diesels for Bismarck, H-39 engines were 4 per shaft, as they were on Panzerschiffe: coupling and gearing of 4 Diesel engines was well tested and posed no problem since beginning in Panzerschiffe (just one minor incident to Bremse, used to test Diesel engines solutions), with Vulcan fluid-dynamic joint being one of most successful propulsion aspect. It avoided vibration/rotation speed differences between engines without soliciting reduction gear, introduced very limited loss of efficiency (a mere 3%) and allowed superior maneuverability and sudden inversion of propellers (Achilles Captain reported he saw Graf Spee turning like a destroyer during battle, thanks to this capability).
H-39 would have 'just' needed more power to be transmitted, however Vulcan technology had been already planned during WWI for SMS Fürst Bismarck (Mackensen class battlecruisers), 90.000 hp, never launched.
IMHO there were surely many challenges but no jump that could have rendered Diesel propulsion for Bismarck hard to achieve, provided final decision was taken in time to allow MAN to fully design such a powerful plant by 1939.

hans

[Thorsten Wahl]

@ Bill Jurens

is there any information available on the max steam-heating-capacity of american battleships.

say one M type boiler can produce about 100 tons of steam at xx atm per hour?

[Bill Jurens]

I take it you are referring to the capacity to provide steam for 'hotel' services in addition to that used for propulsion. That's a tough one to answer as these services represent a variable --and sometimes ill-defined -- load which can, in combat, often be diverted to propulsion, e.g. there is no need to run steam ovens for the galley when in action, and the requirement to steam-heat crew spaces etc., often depends upon outside weather conditions.

If you could be a bit more specific, I could try to look some numbers up. You might want to refer to the paper Strafford Morss and I wrote on the machinery plant of USS Massachusetts (BB-59) in Warship International about 15 years ago. It should be up on JSTOR. This contains a series of complete heat-flow diagrams for the engineering plant. This will give you steam capacity for each component, but not necessarily steam distribution, which, as noted above, somewhat depends upon exactly how much you are devoting to hotel services...

Bill Jurens

[Thorsten Wahl]

Thank you
I meant max amount of steam produced by the boilers available for propulsion and auxilliaries.
I suspect its about 800 tons steam per hour for the complete powerplant at 212,000 SHP +~maybe 150 tons per hour reserve for 254,000 SHP at overload condition


the article 2 only mentions the daily capacity of the main evaporators
BB 55 -2x 40,000 gdp = 80,000 gdp



(sorry for digress)

a comment on the fuel consumptin of the Panzerschiffe.

Daily consumption: Admiral Graf Spee and Admiral Scheer used about 55 metric tons per day, when on search duty( about two month without refueling). Admiral Scheer went from Madagaskar back to a german harbour around Iceland without refueling.

for comparision holiday load alone for the high pressure powerplants of german heavy cruisers and battleships was in the order of ten metric tons per hour (power plants running combat ready)

for realistic combat conditions here is a list

[chuckfan3@gmail.com]

Hello Mr. Jurens,
thanks a lot for your answer and precious info. It's precisely my understanding, reading German damage report.

Regarding the chances to get back, however, I disagree: in 1941 Admiral Scheer got back to Germany after an even longer and more successful cruise, avoiding British patrols in the Denmark Strait, with longer daylight and without such a sharp radar superiority (at that time of war).
IMHO, key point is whether Admiral Graf Spee was actually compelled to enter a harbor for basic repairs (especially to bow hole, I think) or whether she could have tried to stay at sea, to shake off her pursuers (her range was superior, 75% of fuel was still available on board and ammunition was very low for British too), to hide in South Atlantic to fix what was possible to fix, and then to get back to Germany.
I suspect Langsdorff's wound had a weight in his decision. After all, her support ship Altmark was waiting South of Montevideo, for a rendez-vous before planned leave to Germany.

hans

The difference is Admiral Scheer began her homeward trip undetected by the British. They British would to maintain a wide yet dense patrol line for an extended period, at least several weeks, to effectively catch her. Graf spee would begin the trip already precisely located by the brutish. She would have to shake off the shadowers and those intent on bring her to action and then remain undetected for substantial period of time in order to widen the possible time and track window for her return enough to prevent the British from having a high chance of sealing the right passage at the right time.