Bismark´s endurance, fuel bunker and fuel burn.

[RF]

. You will not belive this.
The true new Bismarck story is now ready.
Gudbrandur.

You are quite right, nobody will believe it. This account is contradicted by an overwhelming weight of evidence. And also by the fact that it has taken over sixty years for this rubbish to be cobbled together.

Its rather like the ''story'' of Hood being sunk at the DS battle by a torpedo fired from a U-boat, or the HMAS Sydney being sunk by a Japanese submarine - a Japanese submarine which when finally identified was actually laid down 13 months after Sydney was sunk.

[Vic Dale]

I am not sure what has been going on here, but I thought it would be as well to present Bismarck's and Prinz Eugen's fuel consumption graphs here, plus some information as to Bismarck's fuel state after Hood was sunk;

I present below a graph showing the two ship's respective fuel consumption at given speeds. As can be seen, at medium to high speed, Bismarck would consume roughly 33% more fuel than PG at the same speed. PG burned 685 tons steaming between Danzig and Norway, so Bismarck will have consumed about 900 tons of her 8200 tons. As has been correctly pointed out, a ship may have a certain amount of fuel, but that is not the same as 'usable fuel' which works out at about 90% for the total load taken aboard. Bismarck will have sailed with 7400 tons of usable fuel.

Bismarck and Prinz Eugen's Fuel Consumption.jpg (66.22 KiB) Viewed 2082 times

At code-word Hood - 1800 on the 24th - PG had burned 1883 tons, so Bismarck will have burned 2500 tons, making a total of 3400 tons. This will have left her with 4000 tons. Allowing for 500 tons lost due to the hit in the port side bunkers, she would have 3500 tons remaining, enough to steam at 28 knots for 70 hours, or to cover 1960 nm. France was just over 1300 miles away at that time, so she will have been able to reach France at 28 knots and still have about 600 tons to spare.

[alecsandros]

At code-word Hood - 1800 on the 24th - PG had burned 1883 tons, so Bismarck will have burned 2500 tons, making a total of 3400 tons. This will have left her with 4000 tons. Allowing for 500 tons lost due to the hit in the port side bunkers, she would have 3500 tons remaining, enough to steam at 28 knots for 70 hours, or to cover 1960 nm. France was just over 1300 miles away at that time, so she will have been able to reach France at 28 knots and still have about 600 tons to spare.

...
Is it certain that Bismarck left with 7400 tons of oil ?

[Vic Dale]

It is pretty clear that she did not sail with less than 7400 tons of usable fuel.

I have attempted to assess the total capacity of Bismarck's fuel bunkers from drawings, but the maths is taking me to the limit of my patience. However I will show what I have found;

Using the cross sectional area of the mid-ship side bunkers in section XI which I calculated at 18.5 sq m and reducing by percentages forward and aft as the bunkers narrowed in conformity with the shape of the hull, I arrived at a figure, which could be multiplied by the total bunker length, producing a final figure of 3000 tons contained in the Side Bunkers.

Using the same method, I arrived at a figure of 6000 tons in the Double Bottoms, below the machinery spaces.

Below the side bunkers are smaller ones which appear to be about half their size, but which run the full length of the hull between the armoured transverse bulkheads for and aft. These bunkers run uninterrupted for this length of the ship, so they would hold more than half the load in the side bunkers, which might bring us close to the reserve fuel figure of 1750 tons.

3000 tons in the side bunkers, 6000 tons in the double bottoms and 1500 to 1750 tons in the small side bunkers, adds up to at least 10,500 tons, possibly 10750 tons. Add to this the total capacity of the trim tanks and we are close to the figure given by the survivor who had charge of the oil-fuel storage pumps. 1000 tons in the bow trim tanks and possibly another 750 in the after ones. I have to say that I am surprised that I could get this close and am still wondering where I have made a mistake, but there it is as far as I can go. If anyone is interested, I will happily give them my detailed figures so they can check my workings, though it would be far better if they made a clean start themselves.

The survivor in charge of the pumps, said the ship had sailed short of fuel, but estimated this shortage as 3,000 tons and stated that she sailed with 9,000 tons, being 3,000 tons short of her absolute capacity of 12,000 tons.

Perhaps there is someone who has already made these calculations more accurately and maybe there is detailed information as to which bunkers were designated as reserve bunkers.

[alecsandros]

The survivor in charge of the pumps, said the ship had sailed short of fuel, but estimated this shortage as 3,000 tons and stated that she sailed with 9,000 tons, being 3,000 tons short of her absolute capacity of 12,000 tons.

Yes, but another survivor mentioned Ark Royal's attack was made by 27 warplanes.

Why would a warship want to set sail at overload weight ?

A fully-loaded Bismarck would be ~ 52000 tons, and taking your calculations of extra-fuel, would reach 55.500 tons.

The freeboard, maximum speed, manouvreability and, funny as it seems, fuel consumption, would all be altered quite a lot.

Why would a captain and an admiral decide to handicap their own vessel by overweight , especialy as good speed and swift manouvreing would be required to break into the Atlantic ?

The question becomes even more acute as Bismarck could resupply from supply ships... so she didn't need to have the entire fuel on board..

P.S.: I seem to remember reading an analysisis on thei forum that tended to show the freeboard of Bismarck, as it appears in pictures of the operation, would correspond to a lighter load, of perhaps 50.000 tons on leaving Norway.

[Vic Dale]

I thought it would be obvious that as Bismarck was to carry fuel for PG, that the ship would start out with over load. This will have been reduced as the ship neared the Atlantic, by about 2500 tons, so there would be no great handicap as far as immersion due to fuel was concerned.

The fuel load would be incorporated into the total maximum of 52,000 tons. So if we consider the figure for Light Ship at just over 41,000 tons then fill her up, we get to 52,000 tons.

The ship's command over estimated the air attacks also. The man in charge of the pumps was specifically detailed for that job and as far as I know, such things do not make lightning attacks from the air, so he would not likely be confused about the ship's fuel load.

[alecsandros]

Sources vary.
The baron mentions a full-load displacement of 53.000 tons.
Most other sources converge on ~ 51.000-52.000 tons full load.

It makes sense: on a standard displacement of 41700tons, with 7500 tons of fuel, 1500 tons of ammo and such, and 1000 tons of other loadings.

From your calculus, and extra 3000 tons of oil would appear to be the case.

So, considering various sources, the full-load of Bismarck with 3000 tons of extra oil would have been 54000 - 56000 tons.

Here is a breakdown of weights for 50,955.7 tons displacemnent:

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

[Vic Dale]

What you suggest would not surprise me, after all the immersion rate was 1foot (30.5cm) for each 1500 tons, so loading to 54,000 tons would only add 16 inches (40cm)to her draught at 52,000 tons. I can see no problem with that.

[Vic Dale]

During the past week I have been able to run down the figures for Bismarck's speeds over given time periods between 1700 on the 24th of May until 2130 on the 26th when she was crippled by a torpedo. I have been able to use these figures in conjunction with a consumption graph for Bismarck which I produced some time ago. It gives an accurate view of how much fuel was burned and exactly how much was left when the torpedo struck.

Bismarck sailed from Gotenhafen with 7700m³ of useable fuel aboard. At 1700 on the 25th of may, by my own calculations she had burned 2500m³, leaving 5200m³. Group West made a similar calculation and arrived at a more generous figure of 6040m³.

My own fuel burn graph probably needs some adjustment to give 20% to 24% greater endurance for Bismarck.

Between 1700 on the 25th and 2130 on the 26th when she was crippled by the torpedo, she had burned a further 1590m³.
Using Group West's figures, Bismarck sailed from Gotenhafen with 7700m³ of useable fuel aboard. By 1700 on the 25th, by my own calculations she had burned 2500m³, leaving 5200m³. Group West made a similar calculation and arrived a more generous figure of 6040m³ remaining. My own fuel burn graph probably needs some adjustment to give 20% to 25% greater endurance for Bismarck.

Between 1700 on the 25th and 2130 on the 26th when she was crippled by torpedoes, she had burned a further 1590m³. Using Group West's figure of 6040m³ Bismarck had a total of 4450m³ in her bunkers. Using my own figures she had 3610m³ remaining.

The speeds, running times and rates of burn which I used for these calculations are shown below.

1700 - 0206 8hrs------192nm----24kts--28m³ph----224m³
0206 - 0700 5hrs------140nm----28kts--46m³ph----230m³
0700 - 1300 6hrs------154nm----27kts--38m³ph----228m³
1300 - 1620 3hrs 20m--80nm----24kts--28m³ph-----84m³
1620 - 1920 3hrs 40m--94nm----30kts--50m³ph-----15m³
1920 - 2000 0hrs 40m--20nm----30kts--50m³ph-----30m³
2000 - 0400 8hrs------230nm----29kts--48m³ph -----384m³
0400 - 0600 2hrs--------40nm----20kts--20m³ph-----40m³
0600 - 0930 3hrs 30m--72nm----20kts--20m³ph-----70m³
0930 - 1630 7hrs------133nm----20kts--20m³ph ----140m³
1630 - 2130 5hrs------132nm---- 20kts 20m³ph---- 100m³

Total burn since 1700 on 24th = 1590m³.

With more than 3600m³ remaining in Bismarck's bunkers there is no way that the vessel was short of fuel. I hope I have now made my point

[Thorsten Wahl]

Bismarck sailed from Gotenhafen with 7700m³ of useable fuel aboard. At 1700 on the 25th of may, by my own calculations she had burned 2500m³, leaving 5200m³. Group West made a similar calculation and arrived at a more generous figure of 6040m³.

thats not correct
The calculation of Gruppe West ended at the 24th with a consumption of about 2610 m³


you may have a look at this thread
viewtopic.php?f=37&t=3556
the rangedata/respective the derivable fuel consumption provided by Herr Nilssson were the official figures from the Fahrttabellen Schlachtschiff Bismarck

[Vic Dale]

Thanks to Thorsten for the additional information.

From what is written here I am about 100m³ out.

If we use 7700m³ of useable fuel as the sailing load at Gotenhafen, and a burn rate which consumed 2610m³ by 0000 on the morning of the 24th, we are left with 5100m³.

Assume 27knots for 17 hours for the day (0000 to 1700) at a burn rate of 38m³ per hour and she burned a further 646m³. This makes for a figure of 4454m³ remaining at 1700.

Between 1700 on the 24th and 2130 on the 26th steaming at various speeds, makes for a total burn of 1590m³, during that period, leaving 2864m³. This was sufficient for 57 hours of steaming at 30 knots, or 1700nm. Alternatively she could steam for 75 hours at 27knots, which makes for more than 2000nm. Had she reduced to 24 knots she would have had sufficient fuel for 100 hours of steaming, more than four days. At normal cruising speed of 20knts she would have enough for nearly 6 days.

It confirms that the ship was never short of fuel.

[alecsandros]

It confirms that the ship was never short of fuel.

What about the contaminated fuel in the forward section ?

It's true some was recovered on the 25th, but how much is impossible to know.

[Vic Dale]

No fuel was contaminated in the bow. The bow was flooded in the compartments above the trim tanks and structural damage was limited to the compartment through which the shell passed. Once the water was pumped out of the flooded compartment, the control valves for the trim tanks were accessible and the fuel was no longer isolated.

[RNfanDan]

If Bismarck had ample supplies of fuel as has been fomented in recent weeks (in this thread and others), why then, did Lütjens choose to set course toward the continent so soon? This took him near the western approaches, toward Force H, toward Rodney, and did nothing to meaningfully distance himself from Tovey's forces.

If it is a false precept that he headed for landfall on the continent based on: a) damage to his ship; or, b) shortage of fuel, then, it begs the question of why he did not turn to a more southerly course, or even a westerly one, and rendezvous with one of his tankers? He surely understood the immediate benefit of sending Prinz Eugen on such a course.

Furthermore, Prinz Eugen was incapable of fulfilling the mission role of commerce raider---not because of machinery problems (which could not have been known up to that point), but because the whole idea (unless I am wrong on this point?) was for Bismarck to be able to engage convoys escorted by heavier warships, freeing the cruiser to concentrate on the merchants and transports.

In any event, Bismarck could take care of her own far better than Prinz Eugen, and if the ship was as capable of fulfilling that mission role as has been asserted thus far, it surely seems a fool's folly for the admiral to have turned toward areas of the Atlantic near to British bases (Gibraltar), patrol zones, and neutral ports. Why would he run toward enemy-influenced waters, rather than stay clear of the mainland coasts, as Graf Spee had so successfully done?

This has been one issue that has not been resolved or even thoroughly addressed thus far, and lurks beneath the surface of the whole "Head for Spain/Portugal" theory. Something must have caused Lütjens to steer southeast (in general), toward the continent, where nothing could be gained, PROVIDED that Bismarck was indeed, "fully operational" after effecting bow repairs and recovering her temporary cut-off access to fuel pumps.

Until this is clarified, the stage thus being set won't withstand the weight of the orchestra....

[Vic Dale]

At the risk of waxing lyrical, I would have to pick up my baton and conduct the questioner to the reason for the original intention to make for St Nazaire.

The ship was damaged and trimmed by the bow so that it was digging in at speed and she was listing 9 degrees to port. Through the night Lutjens had been constantly dogged by two cruisers who were shadowing with a new radar with prodigious range. Lutjens at that time was convinced he would not be able to shake the cruisers off if he could not out distance them and as his top speed was limited to 28 knots there was a fat chance of that.

So to France it would have to be. Oddly though he did not steer in that direction, preferring instead to head south - 180 degrees. On detaching PG he steered southwest, which put Captain Bovell's nose out of joint because it delayed the time at which Victorious would be able to launch a Swordfish strike.

The general direction was south, with Wake-Walker's formation on Bismarck's port quarter. Bismarck meanwhile had reduced speed to about 16kts to give PG a chance to get well ahead. In order to maintain speed, the formation behind Bismarck was forced to zig zag and when Suffolk, the nearest ship turned out onto her outward leg at 0306, Lutjens hauled the ship round to the northwest and increased speed, thus shaking off his shadowers. Phase one of brightening Lutjens' day had completed.

Lutjens now shaped a heading toward Lisbon in Portugal as can be seen on the track chart I prepared on the "Lutjens' Intentions" topic. That may or may not have been the intended destination, but that is where the ship's bow was pointing through out most of the day. Now alone, Bismarck was able to reduce speed and make repairs to the holes in the bow with steel plates welded over them, according to one of her survivors. The bow was pumped out and by 2000 it appears she was able to make 30 knots which she did for 2 hours. The ship was now fully fighting fit so there was no urgent need of a dockyard. All options were open. Lutjens had broken out into the Atlantic, stripped the convoys of their battleship and heavy cruiser escorts and now his squadron could cause mayhem at will.

With his options open and with plenty of fuel in his bunkers, Lutjens did not have a lot to worry about, except the usual of not getting caught by a hunting group. At 1842 on the 24th, Group West suggested that if detaching PG was successful an extended waiting period in a remote area was advisable for Bismarck. So even Group west did not think it necessary to go barreling hell for leather toward France at that time and that was the day before the holes were sealed.

A good remote area might be south of the Azores where tankers sailed from France Portugal or Spain, would be able to oil the ship in readiness for a prolonged sweep against the convoys. Tovey would be hard pressed to scrape enough ships together to go hunting for her, so possibly the heat would have died to glimmer in a few more days. With the oil remaining in her bunkers, Bismarck could basically go where she liked and at whatever speed she chose too.