Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Don
Your latest update seems OK to me. Time has come for me to move up to my summerfarm very remote in the deep forrests which means I shall be without internet from tommorrow and  for some time, may be up to two weeks, before I get a satelite connection. In the meantime I shall have a further study of your Skizzenbuch and revert to same when I`ll be on line again. 

Tore

[Don Prince]

Hello Mr. Tore,


Have a good vacation on your summer farm in the forest and I hope its not too far from neighbors or friends.


Regards,
Don_

[Don Prince]

Hello Mr. Tore and Maciek,

Today, I just completed my permission list from the three (3) web sites which provided the documents for Skizzenbuch:

uboatarchive.net - Skizzenbuch 34 plates, U-570 reports and B/W photos
u-historia.com - Line drawings and a few color photos
uboataces.com - Most of the high resolution color photos we used for illustrations came from their CD

I will most likely sign and return the book contract to Schiffer Publishing, Ltd., next week...  The publisher suggested I get a small photo of my contributors and a short Biography.  I plan on replacing the photo of me at the end of the book with a better photo when I was at the Chicago Museum of Science and Industry.   I'm not sure if it will happen, but I asked my friend Jak. P. Mallmann Showell who has written many books about the history of U-Boats during WWII to do a short "Forward."  If that happens, I think it would be great!

Regards.
Don_

[tore]

Don.
I am finally back on the net. Good to learn you probably shall sign the contract next week. I have checked the skizzenbook up to page 77 and have a comment on page 69 "e" valve selection on the fuel daytank. I think you somehow got it wrong. Below I have made a sketch showing how the selectioncock is working I guess is  selfexplaining. Otherwise I cannot find anything wrong. However it strikes me when you substitute  an original German manual text translated  into English with an alternative text which may be a simpler to understand for a layman, you maintain the translated text from original German documents as well . For a layman the translated manual text is not easy to read as the English text sometimes can give an impression that the translator in spite of using the correct words sometimes do not fully understand the meaning of what is translated. It is not easy to translate technical manuals as you really have to know the working of the items you describe.  I guess what I am trying to say is, you get a double text on the same subject which might be confusing for the layman reader, for a professional however the original translated text shall be OK and that`s perhaps why you kept it.
Tore

[tore]

Don.
Skizzenbuch.  I don`t fully understand your text on page 79 under plate 10. The system works like this: If submerged and the hullvale "a" leaks or is left open, the internal pipesystem shall be exposed to the seapressure but is protected by the reliefvalve "f" in the engineroom. The internal fueltanks 1 and 2 are protected by the shut off valves "C". If these valves are open each fuel tank has a unit consisting of a reliefvalve for overpressure "f1"and under pressure "f2", fitted with a manometer for the absolute pressure prevailing in the tanks. These units protect the tanks for both over- and underpressures.
See my answer to Maciek 2651 and 2653.
Tore

[tore]

Don.
Skizzenbuch. On page 88 you have an elaborate description of the assumed waterlevel height of the compensating tank introducing the keel and the wind deflector. This might be complicated to follow for the average reader and as all the figures we have of the tank  would be approximate anyhow, I guess it would be simpler just to  introduce the approximate figures directly. As you see on my image below the watersupply pipe from the engines ends up in a pipe some 20 cm above the bottom of the tank to prevent a complete draining when the engines are stopped. When the engines are running the water is filling the tank until the overboard pipe approximately. 10 cm. from the top of the tank when the water goes overboard normally keeping the tank topped up 10 cm. from the topcover. Further the bottom of internal fueltanks are not going all the way to the lowest part of the pressurehull (see my sketch). This means that surfaced an estimated pressure of the internal fueltanks open to the system might vary  between 740 and 700 cm. watercolumn approximately corresponding to 0.74 and 0.70 kg/cm2.  or 10,5 and 9,95 lbs/sq. inch.
Tore

[tore]

Don.
Having checked your Skizzenbook up to page 108, I have the following last remarks: Page 109 Safety valves . You have a remark on the safety valve (Reliefvalve) on the main blowingpanel dealing with the event that you had an air pressure supply of only 25 kg/cm2 or less that you could adjust the reliefvalve or improvise. In such unlikely event you don`t have to do any thing else to the relief valve or other components but blowing whatever you got of air so I suggest you skip that paragraph.
On your description of the electric aircompressor,first line lunching to be substituted with launching torpedoes .
The description of the Junker compressor I believe is superfluous as you have a description on page 92 through 97.
Tore

[tore]

Don.
Skizzenbuch page 116. Coolingwater. The header tank uses the water to pressurize the RFO tanks... I suggest you revise the text to: ...is used for pressurizing and watercompensating of all fueltanks except RFO 1. The excess water goes overboard via the external mufflers and headertank overflow.
On the same page you mention the coolingwater for the Junker, I suggest you change the text to:....... diesel powered unit having its own attached rotary vane coolingwater pump and external exhaust cooling watersystem via e3.

Page 123. The text starting with:  The engines were Krupp  for the VII Cs..... I think you quoted my text dealing with a description of the main engine of KNM Kaura ex U-995. As you know the VII Cs main engines could be Krupp Germania Werft or MAN the latter having the Buchi system exhaustdriven supercharger I suggest you rewrite the text to make it more general for the VII Cs.
By this your Skizzenbuch is checked up to page 133.
Tore

[tore]

Don.
Skizzenbuch page 157. Starting procedure main engine. I suggest you change the sentence .....the starting handle is put in a start position...... with: the startinghandle is put in a start position, air is admitted to the top cylinder of the starting valve pushing the valverod.....
Page 170. Stb. exhaust blowing valve in the engine room. You write this as black, it is green ( not very important as we did not have these colours on the valve wheels.
You describe correctly that the bores in the  main exhaust valves wheels were  for putting a bar into the wheel for a larger torque. We did not use the bar very often but waited until we reached some 2-4 meters depth creating a nice backpressure when we were grinding the outer exhaustvalve, however when we reached 5-6 meters the backpressure would be too large for the pneumatic motors to turn the valve disc so you had to be quick.
A minor thing, you are quoting some of my remarks where I am referring what I or we experienced or did under different circumstances like page on page 157 .... I personally checked the combustion by........It might give a confusing or even wrong impression without mentioning who are behind I or we. You could rewrite into a more general form skipping the we and I or quoting who is behind the statement, otherwise you get the blame for my possible mistakes .
Your Skizzenbuch has now been checked up to page 172.
Tore

[Don Prince]

Hello Mr. Tore,


Post 1752, I used your latest drawing as suggested.  Is the text OK?  I'm not sure you wanted me to change anything.  I have bee AWOL (Absent With Our Leave) for this weekend and will get back to work on Skizzenbuch.


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


I believe I got everything updated...  I'm not too sure what you wanted me to change on page 109...  I left the paragraph in there about the Junkers compressor because of too much open space if deleted...


I uploaded the latest version of Skizzenbuch into dropbox...


Thank you for taking your time to correct my typing errors.  I don't usually have torpedoes for 'Lunch"!!!



Regards,
Don_

[tore]

Don.
Your reply #2664 I am not sure which drawing and text you are referring to as  post nos are just the a number indicating my total posts, could you refer to reply number?
I have checked your Skizzenbuch 1 before your update of today up to page 193 and have a few remarks. Page 187 clutch for hydroplanes you are quoting my description referring to the coloured sketch 2. paragraph. Somehow the green coloured part is quoted as wormwheel housing. The housing is not shown and the green parts are the e-motor worm gearwheel assembly.
On page 188 you have a funny misspelling ....... hydroplane setting while cursing   on the surface.....
On page 191 you are referring to the inclinometer (along ship) as showing the tilt, we normally used trim. There is another inclinometer showing the list ( atwartship tilt) I remember looking frequently on the device in rough weather in view of the battery acidspill. I guess it was in the control room but can`t find it on U-995, may be somebody pinched it.
Page 193....... Keel depth varies slightly depending on the loadfactor.... It depends on the sea salinity and temperature as well, you see it on the classification marks on every shipside.
As to your to days #2665 I shall revert later.
Tore

[Don Prince]

Hello Mr. Tore,


I made the suggested changes and spelling corrections...  I uploaded the latest version of Skizzenbuck to dropbox.


 "Hydroplane settings while cursing on the surface" was changed to "Hydroplane settings while cruising on the surface"  I guess I misspelled 'Cruising" and word automatically inserted "cursing"…… Then after that, it passed Spell Check!    Many times


Regards,
Don_

[tore]

Don.
Skizzenbuch1 of today:  page 78 text under image misprint .... height of the water column form the deck...... You are on most of the text concerning fueloil tanks as from page 78 and onwards referring to RFO tanks, you better check these texts as most of them concerns FO tanks and not only RFO (reserve fuel oil tanks).
Page 79 see my reply #2659
Page 116...... The RFO tanks and the excess water is drained back.... suggest you skip this sentence.
As far as I can see apart from the above correction everything is OK up to page 193.
Tore

[tore]

Don.
Skizzenbuch page 199. You describe the man operating the engine telegraph as giving order to the electrician and that he responds after the command is completed. This not quite the case, the engine telegraph is used both for giving orders to the dieselroom as well as the E-room depending on the prevailing propulsion configuration. In this case it could f.i. be a dieselconfiguration on a surface attack and the orders would have been given to the diesel engineers. In any case the order procedure is different from what is stated by you. The speed order is given by the officer on watch, only to be overruled by the CO, in that case he takes over the command. When the order is given to the helmsman wherever he is placed, he put the engine telegraph pointer to the ordered speed, repeating the order to the officer on watch (or CO) the order is transmitted to the diesel room or E-room depending on the configuration. The engineer or electrician put the telegraph pointer to the ordered speed prior to the execution, not after the order is executed, as a sign they have understood the order correctly and the helmsman report to the officer on watch.
The "speedgauges as you calls it" are called tachometers. Skizzenbook checked up to page 199.
Tore