U 534 beam

[Capt Kremin]

Hi All


Just thought this might be interesting to those building type IX models, but I have just recently managed to measure the beam.


Drumroll!!


6.765m +- 10mm, the relatively large tolerance is due to a possible parallax error in the measurement, which according to various sources is the beam of the type IXc not a type IXc/40 which according to the werk no. is what the U 534 was built as.
Unfortunately it is not possible to measure the length as it was cut into 5 pieces (losing 40mm), 2 sections were joined (unknown addition) and several of the sections have access to only one end.
I have my own theory as to why the measurement is different to the normal specs written down, but I'll let some else have a go.


Regards
Jon

[dougie47]

Hi Jon,
 
I'm certain you have the measurement correct and that U 534 was indeed the size you measured. There is nothing like having a real U-boat to play around with!
 
My first point is that the figures in reputable books and websites are not sacrosanct. Recently I have been reseaching the Atlantic bow on Type VIICs and have identified through period photos this bow on 25 VIICs. I estimate the Atlantic bow was on over 165 VIICs. If I am right then there were over 165 VIICs which were 13cm longer than the 67.1m figure attributed to them in books. If there is a mistake / omission with VIIC length then why not with IXC/40s?
 
Next question is: was U 534 an IXC/40? I think we may be reasonably certain it was (otherwise U 513 to U 538 would have to be IXCs and that seems impossible).
 
The idea behind the IXC/40 was to find another 6 tons of fuel storage over the IXC. The size of the pressure hull was the same on IXCs and IXC/40s so I think the idea that folks have at present was that the overall width of the IXC/40s was 10cm slightly larger and that the extra fuel capacity was contained in the space between the pressure hull and outer hull casing. But if we are, for a moment, to think of all the IXC/40s as being 6.76m (same as IXCs) then the extra fuel can't have been stored here. Where else would the extra 6 tons be stored?
 
One possibility is length. The IXCs and IXC/40s were both supposed to be 76.76m. The extra fuel could be stored if the IXC/40s were in fact a little longer than the IXC/40s. It seems almost daft to suggest this, given that every source specifies that they were the same length. But, given that over 165 VIICs were longer than the figure given in all the books, it may remain a possibility.
 
Second possibility is height. In the Vom original book the height of the IXC is 9.60m and the height of the IXC/40 is 9.484m, suggesting that there was a reduction in the height when the IXC/40 was designed. However, on uboat.net the height of the IXC is 9.40m and the height of the IXC/40 is 9.60m (the complete reverse of the Vom Original figures). Perhaps uboat.net have mixed up the figures but they have experts on that site so I am not sure this has happened. It could be that the guys on uboat.net really do think that the height of the IXC/40 was greater than the IXC. If it was then perhaps the extra height might allow for the extra 6 tons of fuel capacity that the IXC/40 had over the IXC/40? 
 
So I'm thinking that the IXC and IXC/40 may have been the same length and same width but the IXC/40 was higher than the IXC, thus allowing for the extra 6 tons of fuel to be stored.
 
Last point - if U 534 was 6.765m wide what about the rest of the IXC/40s? Were they all the same width?
 
Cheers,
 
Dougie
 

[Capt Kremin]

Hi Dougie et al


Here is my take on type IXa-c dimensions.


The pressure hulls were the same size upto the 'D' type.


This would imply that the keel would be the same dimensions.


The beam of the b/c types was the same, the IX(a) might have been narrower, personally I'm not convinced.


I also believe that the overall length of the hulls were the same.


The height is almost an irrelevant figure as the turm would affect this figure more than anything else.


Why are there different figures: most of the current figures come from the allies, they would be measuring captured/surrendered boats, probably quickly and in difficult circumstances.


The difference in fuel capacity is probably down to a re-arrangement of the tanks after finding that the earlier boats had surplus positive buoyancy, as fuel oil has positive buoyancy the adjustment of the buoyancy/fuel tanks would not be as radical as you might first think. Also once empty the fuel tank becomes a buoyancy tank anyway.


Bottom line, if a detailed measurement of the U 534 (difficult and the U 505  I believe that it would be found that they have the same hull dimensions.


Regards
Jon

[dougie47]

Hi Jon,
 
The difference in the fuel capacity is a very good argument. It could be as simple as that. The designers could have rearranged the tanks inside the boat to find an additional 6 tons of storage and that could be the only difference.
 
This makes additional sense when we consider that they name they gave was IXC/40 (in other words a sub-variant of the IXC). If they had changed the actual outer dimensions they might have changed the designation to IXD (with the IXD becoming the IXE). 
 
I think your measurement and argument indicates that externally (and from a modellers' point of view) that the IXC and IXC/40 were the same. The individual features (deck type, snorchel, tower type, magnetic compass, cut out foredeck etc) were features implemented at various time and were not specific to a certain variant. So although the new "IXC/40 U 190" kit is labelled as an IXC/40 we could use the new kit to depict a IXC with late war features (either U 516 or U 518, the only two IXCs which appear to have lasted long enough to get the cut out foredeck).
 
I'm having a bit of deva vu here. I've been finished an article (which will be posted soon) in which I have argued that VIICs and VIIC/41s were externally (and from a modellers' point of view) the same, with the thickness of the pressure hull being different. It's the same argument for both types.
 
Cheers,
 
Dougie

[Capt Kremin]

Hi Dougie,


It sounds to me that we have reached the same conclusion on U-Boat construction, coming from different directions. I believe that most, if not all differences in dimensions of the type iX family up to D are from measuring errors. I have seen in allied reports of the type IXc/40 figures such as it holds 60 tons of extra fuel and the pressure hull is 5.5m in diameter. The former figure unlikely and the latter not correct.


From a construction point of view, if you are going to change any dimension the length would be the easiest to change as you would only need to add an extra section of the already profiled plates. Similar to when the Hercules aircraft were enlarged, they were lengthened, overall a much easier job than trying to increase the diameter.


Regards
Jon