View Full Version : Good at math? I have a problem for you.
Ducimus
01-06-07, 04:07 PM
It's all about FUEL! Im sure this will draw Letum like a magnent :lol:
One of the biggist mysteries to me, is exactly how much fuel is in a uboat, and.. the rate of consumption. But to boil the fat away, ive always wondered exactly how much fuel a trip to X destination would consume.
Awhile ago, i made this observation. Its a bit from Donitz's war diary:
(Picture linked cause it skews the page)
http://www.ducimus.net/sh3/BDU_on_Fuel.JPG
From this i make 4 assumptions:
1.) He's talking about Nautical Miles
2.) CBM means, Cubic Meters
3.) Hes noting how much fuel a uboat will have after making the trip To that area. Not how much they have to operate in that area, with the to and from trip already accounted for. (or do i have this backwards?)
4.) These are ballpark figures, not exact ones. We have no idea under what conditions or assumptions (if any) he made these calculations.
Now, according to this page:
http://www.uboataces.com/uboat-type-ix.shtml
A....
IXB has 165 Tons of fuel
IXC has 208 tons of fuel
IXC/40 has 214 tons of fuel.
So my thought is, to take BDU's estimate of how much fuel is remaining in the tanks after making a trip to X locaton, convert it to metric tons, and then convert that to a percentage against its total capcity?
What im having trouble with, is the density of the fuel, and finding an applicable formula to apply it too. And, i have to admit, mathimatics was never my most keen subject.
azn_132
01-06-07, 04:10 PM
It's all about FUEL! Im sure this will draw Letum like a magnent :lol:
One of the biggist mysteries to me, is exactly how much fuel is in a uboat, and.. the rate of consumption. But to boil the fat away, ive always wondered exactly how much fuel a trip to X destination would consume.
Awhile ago, i made this observation. Its a bit from Donitz's war diary:
(Picture linked cause it skews the page)
http://www.ducimus.net/sh3/BDU_on_Fuel.JPG
From this i make 4 assumptions:
1.) He's talking about Nautical Miles
2.) CBM means, Cubic Meters
3.) Hes noting how much fuel a uboat will have after making the trip To that area. Not how much they have to operate in that area, with the to and from trip already accounted for. (or do i have this backwards?)
4.) These are ballpark figures, not exact ones. We have no idea under what conditions or assumptions (if any) he made these calculations.
Now, according to this page:
http://www.uboataces.com/uboat-type-ix.shtml
A....
IXB has 165 Tons of fuel
IXC has 208 tons of fuel
IXC/40 has 214 tons of fuel.
So my thought is, to take BDU's estimate of how much fuel is remaining in the tanks after making a trip to X locaton, convert it to metric tons, and then convert that to a percentage against its total capcity?
What im having trouble with, is the density of the fuel, and finding an applicable formula to apply it too. And, i have to admit, mathimatics was never my most keen subject.
What? I dont get what this is all about.
Ducimus
01-06-07, 04:14 PM
What? I dont get what this is all about.
In a nutshell.
60 CBM is how many ton's?
X number of tons converted from the CBM is how much of the total fuel capcity as a percentage?
edit: and to me the question still remains, is BDU talking about how much fuel is in the tanks after making the trip, or how much fuel the boat has to operate in that area, not counting the fuel used going to and from that area. I think that answer lays in how large or small a percentage the "CBM" is against a boats total fuel capcity
hyperion2206
01-06-07, 04:20 PM
I searched the internet and found that for example 140 CBM equals 140000 liters or 36984.087330141 US liquid gallons. Hope that helps.
nightdagger
01-06-07, 04:21 PM
Density = Mass / Volume.
Find the density and either the mass (tons) or volume (cubic meters) and you can convert.
bigboywooly
01-06-07, 04:31 PM
From the way it reads
The Uboats will have that much fuel left to operate IN the region
In other words journey to and from removed from equation and thats whats left
Of course it has to be guess work figures as weather/engine condition and usage and evasive tactics employed on either route would all impact on fuel reserves
And I dont think they had at that time actually ran a boat to those locations
And of course you dont know whether that includes refuelling:doh:
hyperion2206
01-06-07, 04:51 PM
If you look at this page Sydney seems to be the nearest location, therefore they U-Boats must be stationed in Penang, right? But why does a IXC only have 140 cbm of fuel left (I mean it's only 2200 miles). So I guess 140cbm is the amount of fuel that can be "wasted" in the operation area, when 140cbm are used it has to return.:hmm: But that's just crappy guesswork.:nope:
Ducimus
01-06-07, 06:27 PM
If you look at this page Sydney seems to be the nearest location, therefore they U-Boats must be stationed in Penang, right?
He meant the OTHER sydney :D
http://en.wikipedia.org/wiki/Sydney,_Nova_Scotia
Mav87th
01-07-07, 02:37 AM
Perhaps you can use this pdf. Its a description of how to convert to the XXI made by von Topp to help other commanders.
It talks about fuel and usage of it.
http://files.filefront.com/berlegungen_zum_Typ_XXIpdf/;6485432;;/fileinfo.html
hyperion2206
01-07-07, 05:20 AM
If you look at this page Sydney seems to be the nearest location, therefore they U-Boats must be stationed in Penang, right?
He meant the OTHER sydney :D
http://en.wikipedia.org/wiki/Sydney,_Nova_Scotia
There are 2 Sydneys?:nope: I forgot that the english speaking people are not very creative when it comes to naming their cities:p:rotfl: (No offense ment;))
Sailor Steve
01-07-07, 03:52 PM
Nothing of the kind. Colonists liked to name cities after ones in the Old Country to remind them of home. There are two major Portlands in the U.S., plus a bunch of other cities and towns named for former home cities in a variety of countries.
Both Sydney's were named after the then(1788) English Home Secretary, Thomas Townshend, Lord Sydney. This was a common practise as explorers used the names of people who commissioned their journeys or whom they had a chance of gaining favour from.
There are also Sydney's in North Dakota, South Africa, Vanuatu, and Florida.
What im having trouble with, is the density of the fuel, and finding an applicable formula to apply it too. And, i have to admit, mathimatics was never my most keen subject. I always let my navigator calculate the maximum range at current speed. It's interesting though, one time I got the message 'We're out of diesel fuel, Sir!', but the engines still could ran an additional 200 km. So I think you also got a reserve or something?
Dietrich
01-08-07, 08:11 AM
[quote]It's interesting though, one time I got the message 'We're out of diesel fuel, Sir!', but the engines still could ran an additional 200 km. So I think you also got a reserve or something?
If you're really desperate, go to periscope and get another 50+km out of your batteries.
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