Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Do.
The images and photos sometimes distorts the dimensions and distances to an almost unbelievable picture, don`t believe everything you see, particulary from the museum U 995 as they have in addition made several changes from the original.
Tore

[Don Prince]

Hello Mr. Tore,


I have placed the latest version of Skizzenbuch 11 x 17 - M into dropbox.  I updated the graphics and some of the text on the Junkers diesel compressor pages 92 through 97.


Regards,
Don

[tore]

Don.
Skizzenbuch.  A few comments.
 Page 93 2nd last section..... through small springloaded valve in the separating plate... and , for approximately 2/3 of the inward stroke,  via the valves in the beltchamber encircling the first stage cylinder.
Page 94 Bouncing chambers. I guess you should reduce the importance of the bouncing effect of the first and 2nd stage bouncing chambers a bit. As I previously have said the major bouncing, is created in all the compressor stages by the pressure maintenance valve situated  in the HP line after the 4 stage cooler. This valve check that the compressor do not supply air to the banks before an adequate bouncing pressure is built up in the various stages. The pressure is very quickly raised ( as the there is no airdelivery) and is adjustable.  The compressor start to supply air when a lowest pressure in the fourth stage is ,as far as I remember, 170 kg/cm2.
Page 97 The image of the Junker compressor air inlet is a bit different. As we have touched upon before  we have two inlets, one for the compressor and one for the scavenging air, both having common airinlet filter. I have tried to make an updated image below.
Tore

[tore]

Skizzenbuch final checking.
On page 87 second section you are still cursing on the surface.
Page 92. Second section .....connected to the first and forth....Fourth.
Page 339.... are only used if the U boat has been damaged as a result of a aircraft machine gun.....It is used in any event of damage to the ventduct.
Page 443 Diesel engine lubricators.  Right. The lubricators... Left.


Tore

[Don Prince]

Hello Mr. Tore,


1. I hope I have stopped "cursing" on the surface...  Page 87
2. I added your text to page 92
3. I cleaned up the bouncing chamber paragraph and came to the conclusion that the bouncing chamber NEVER goes negative. Page 94
4. I updated the drawing on page 97
5. Page 339, I added your text
6. Page 343, some day I will learn which is Left and which is Right!


I uploaded the latest version of Skizzenbuch 11 x 17 - M to dropbox and I will wait for your OK before submitting this final document to Schiffer...  After this phase begins the tedious process of re-configuring Skizzenbuch for the publishing printer.


Kind regards,
Don_

[tore]

Don.
I guess your last corrections are OK. It`s probably impossible to get such a publication flawless as you have put together a number of informations from a so many sources. Anyhow I believe your Skizzenbuch shall give a unique contribution to the understanding of the working and operation of the VIIC`s. The book is more comprehensive than any I got hold of when I started to operate the KNM Kaura ex U- 995.
Tore

[Don Prince]

Hello Mr. Tore,


Thank you for all your help with "Skizzenbuch: The U-Boat Type VIIC Project".... The best thing for me to hear is that the last corrections are OK, because you are the expert in my opinion and your judgement matters so much to me!


I will stay in touch as always.


Kind regards,
Don_

[Don Prince]

Hello Mr. Tore,


I just finished a "Prologue" in the first section...  These two pages and 6 drawings are intended to give the reader just a little of the basics of when diving and surfacing the U-Boat.  I do not cover an "emergency  or crash dive sequence.  I leave that to be covered within the book.


If you would be kind enough to review what I have done, but keeping in mind this is not intended to cover every detail.  In a few weeks, I may have a "Foreword" by Jak P. Mallmann Showell; who has written many books on U-Boats.


I have uploaded the latest version of Skizzenbuch 11 x 17 - M to dropbox...


Regards,
Don_

[tore]

Don.
I have read your "Prologue" and have following remarks: IV  Q was normally not flooded only on warpatrols when you expected a quick dive would be nessecary. Thus Q did not participated in the normal dive.
Middle drawing: when the wind deflector on the bridge and the stern is submerged ( not flooded) simontaneously the boat is on the proper divingangle.
MBT 2 and 4... Vented through a common vent trunk..... and there is a ventvalve lever to blow.... vent.
Otherwise I think the prologue is an exellent idea.
Tore

[Don Prince]

Hello Mr. Tore,


Thanks for the corrections...  I think I got it correct.  The 2 pages are in a column format and I run into spacing issues if I add a line.  So, I combined the center paragraph so I could get things right.  I'm no expert with MS Word columns..


I uploaded the latest version of Skizzenbuch 11 x 17 - M to dropbox..


Regards,
Don_

[Don Prince]

Hello Mr. Tore and Maciek,


I just got an email from Jak P. Mallmann Showell with the following comments....  Should I change all the German words in the plate indexes that end with "sz" to "ß"?

In many places you use the old fashioned "sz" - this was replaced by a symbol looking like a"B" (ß) and in modern usage since before WWII was written as "ss" instead of "sz"

Regards,
Don_


In many places you use the old fashioned ‘sz’ - this was replaced by a symbol looking like a ‘B” and in modern usage since before WW2 was written as ‘ss’ instead of ’sz’

[tore]

Don.
I am not a language expert but to me it is natural to use sz when the other letters are gothic.
Tore

[Don Prince]

Hello Mr. Tore and Maciek,


I sent an email to the U-Boot-Museium in Cuxhaven Germany and receiver the following response...


Dear Don,
since Mr.Monte is not longer on board of our team, but left for family reasons,
I can possibly help you.
In the old times the German language had a "ß" that was a combination of "s" and "z".
Since the handwritten (Sütterlin) letters resembled a "ß", it grew to one separate letter.
But in the meantime resp. since 100 years there is no more written "sz",(it would be incorrect to use it)
but always "ß" when written in small letters, but "SS" when written in capitals,
Messgefäß or MESSGEFÄSS.
We all wish you good luck and success with your certainly very interesting book.

Stay in contact, kind regards
Jutta

 
 Dr. Jutta Baberg
 Deutsches U-Boot Museum
 Lange Straße 1
 D-27478 Cuxhaven-Altenbruch
 
 
 


What do you think?


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


I had to re-write page 80.  I would like to assure that I have gotten your lesson on fuel tank compensation exactly correct, just stated a little different...


The above diagram is indicating the various valves involved in a fuel configuration of the saddle tanks. As a matter of interest, I made a quick calculation of the weight compensation for the difference between the saddle tanks filled with fuel oil (87% the weight of sea water) versus the saddle tanks filled with compensating sea water. With all 4 saddle tanks filled with compensating sea water the weight increase is about 6.5 tons which then had to be taken from the regulating tanks to balance the U-Boat's weight. In the case of not being water compensating tanks, the empty saddle tanks weight loss would be about 43 tons of fuel which would require an equal weight of sea water to be pumped into the regulating tanks to balance the U-Boat's weight. With a total regulating tanks capacity of 24.6 tons, this would be an impossible task. If you do the same exercise for the internal fuel tanks, the total weight increase by compensating sea water filled tanks would be about 9.2 tons and with the saddle tanks increased weight of about 6.5 tons, the total weight gain is about 15.7 tons and still possible to compensate with the regulating tanks' capacity of 24.6 tons. However, without sea water compensating tanks over all the loss of weight would be about 61.5 tons for the empty internal fuel tanks and about 43 tons for the empty saddle tanks; the U-Boat is now about 104.5 tons lighter which must be compensated. This of course was a play with figures with no realistic use, but is just an example of one of the advantages of water compensating.


Regards,
Don_

[tore]

Don.
I guess you got the idea correctly and again this is a play with figures only. The watercompensatings 2nd advantage is the reduction of the free surface effect which might upset the trim. Reverting to your last Skizzenbuch question soonest, but I am having beginners trouble with my new PC.
Tore