Tores mailbox VIIC and VIIC/41 operation and technical details

[Don Prince]

Hello Mr. Tore,


This looks to be a general wiring schematic of U-101 a Type VIIB U-Boat.  I have never seen a general wiring schematic for a U-Boat, and most likely never again (very unique)!  This will not fill in all the blanks, but it does provide a good base to piece each system into place when ever I can find them.  The schematic list U-101 and Blohm & Voss, but U-101 was built by Fried. Krupp - Germaniawerft, Kiel...  Interesting?


Do you have any idea as to the cost to copy your schematic?  If it were not overly expensive, then I would be willing to reimburse you for your cost, time, and mailing expenses for a copy.  They usually put blue prints in a mailing tube for shipment...


Regards,
Don_

[VIC20]

Do you have any idea as to the cost to copy your schematic?  If it were not overly expensive, then I would be willing to reimburse you for your cost, time, and mailing expenses for a copy.  They usually put blue prints in a mailing tube for shipment...

I would say a good high resolution scan in a copy shop would be the best solution for this - I guess that's cheaper than mailing and you could share it with dropbox or other free cloud providers.

[tore]

Don.
The drawing is pretty shot and is about 5 feet long in a roll, but I shall consult one of my grandsons who are more conversant in the present days possibilities of restoring. I believe Mark`s suggestion could be an alternative. I don`t believe it is a VIIB schematic, if you look at the title of the drawing it is stamped U 101 and a black square covering the last figure. Blohm & Voss had a contract for building a series of VIIC/41 which were listed as 1010 up to 1019 of which U 1013 up to U 1015 and U 1017-U 1018 were suspended U 1011 and U 1012 were damaged at the yard beyond repair by an airraid July 1943, U 1016 was scuttled somewhere in the Baltic I believe, but U 1019 surrendered in Trondheim Norway may 9Th.1945. I am inclined to believe the drawings were "borrowed" by the Norwegian prior to handing over U 1019 for the deadligth operation.
As I obviously has taken the drawings home for studying, some of my scribblings are on it,  while being EO on the Kaura ex U 995 I would assume they are from the B&V VIIC/41 series used at that time by me for our only VIIC/41 KNM Kaura.
Tore

[Don Prince]

Hello Mr. Tore,


I figured it was a fairly large schematic....  In 1966, I went to the NCR Company Technical Training Center in Dayton, Ohio, to get trained on the Class 450 proof machine.  The 450 was a 20 total mechanical Accounting machine with an OCR printer for encoding the amount on the bottom of a check  It also had a 20 pocket check sorter and a 20 receipt printer module unit.  This was a electro-mechanical monster that failed many of the older mechanical service engineers.  I was previously trained on the Class 390 computer system in 1963, so this was a piece of cake for me.  It had cam switches timed to enabled wired relay logic to enable other cam switches to energize solenoids to engage mechanical functions.  The schematic was 5 x 10 feet and I remember taping it to the wall at night to study the circuits.  The next day we had to demonstrate the schematic circuits section to the instructor's satisfaction!


In January 1963, I was an apprentice new hire with 9 months field experience.  When I was trained on the computer system, every Friday morning there was a "You Bet Your Job Test."  If you scored less than 90%, then you were fired that afternoon!  Our class size was 22 students and 12 months later when I completed the class our number was 11 souls.  Those were the good old days...


Regards,
Don_

[VIC20]

Tore, from the manual:

For blowing regulating tanks, regulating and reserve fuel oil tanks, and negative buoyancy tanks a blowing manifold is provided in the control room.  The safety valves for regulating tanks and regulating and reserve fuel oil tanks are set at 13 at and for negative buoyancy tanks at 10 at.  Each regulating tank has a pressure differential gauge installed.

That means you can't blow the regulating tanks & cells at depths deeper than 130m right? Only pumping should work then.
Which pressure differential are the gauges showing?

[tore]

Mark.
Not everything is mentioned in manuals, when you are in trouble  the system is open for alternatives, if f.i. you have a lot of water in the bilges I would pump this in a non pressurized regulating tank using the mainbilge pump in parallel, filling the regulating tank. Then pressurize the regulatingtank at fi. 12 ata, put the main bilge pump in series for suctions from the regulating tank, having a suctionpressure say 110 mwc, boost that up with the pump if needed to say another 105 mwc having a capacity of 500 l/min (diff pressure  105 mwc) against total 215 mwc. overboard, hoping the pump, pipe, valve and valve stuffingbox can take it. Same goes of course if you like to pump out water already in the regulating tank. May be a VIIC/41 can survive such depth, possibly not a VIIC, anyhow this is just to give you some fantasies which may be could be built into a game ( and real life) giving the innovative players a chance to survive.
Tore

[VIC20]

Ah… nice! You assist the pump with pressure from the tank. Where exactly is the exit to outboard for the pump located?

[tore]

Mark.
I was carried away a bit , I guess the official rules are: the static pressure (difference between inlet and outlet) of the main bilge pump  should not exceed 8 atu appr. 80mwc. you could pressurize the regulatingtanks up to 14 ata (app.130mwc.) you can exceed that if you pressurize the adjacent tanks ( Q ,reg-and f.o.bunkertks1) somewhat to reduce the bulkheadstresses, say 3-4 ata.That should give you a better pumpcapacity at 210 m.
Tore

[tore]

Mark.
The connections to the sea are shown on the sketch below. Note it is an outlet to Mbt 3. as well.
Tore

[VIC20]

So you could pump to MBT3 instead and try to blow it out with hp air?

[tore]

Mark.
Remember when you are submerged the Kingstons are open and MBT 3 has the ambient sea pressure. So why MBT 3 at all? Well let assume you are pumping the oily bilges and do not want to pump it overboard because you are laying deep hiding and an oilslick is betraying you . You pump it in MBT3 and let it sit there till you blow the MBT3 for surfacing in safer water later.
Tore

[Don Prince]

Hello Mr. Tore,


I have been reviewing back post and I learned that the steam heating system is only used when in port.  That fact makes me feel a lot better because I could not find a heating source on the steam heating Plate...  However, that brings some questions to mind.


1.  When the U-Boat is running on the surface in the North Atlantic at winter time, Is the heat source the diesel engines and using the ventilation system to distribute the heat?


2.  When the U-Boat is running off the coast of Spain, or even worse yet in the Mediterranean, at late summer, doesn't it get kind a HOT!  What do you do to get cool?  I believe the water if pretty warm as well; will diving help at all?


#.  If the U-Boat is sitting on the bottom, say at 150 meters Off the coast of Norway, Isn't it really cold down there?  You can't just throw another log on the fire...?  What do you do to keep warm?


Regards,
Don_

[tore]

Don.
The diesel engines did not take part in the compartment heating and most of the heat dissipation went overboard, in fact sometimes it could be a bit chilly at the maneuveringstand as a huge amount of cold air was drawn in via the dieselair duct. The heating was primarily electric. I cannot remember it was excessively hot in the summertime, this was the time before airconditioning was common and allthough I remember on board surfaceships it could be hot in the Mediterranean most of the submarine was submerged all the time and the sea temperature was some 20-22 degrees C. However people 46 men, electric motors, galley, battery charging etc gives heat dissipation and the only way we could get rid of that was by running the ventilation system taking air from outside, if the air was warm it would not help a lot. 
The sea temperatures along the Norwegian coast varies a lot and particularly in the deep fjords. Offshore the Golfstream keep an average almost constant temperature and the water never excessively cold, in the fjords it varies with the seasons. Particularly in the spring when you have melting of snow and ice creating layers of coldwater with less salinity and making it difficult to keep and good trim. However the layers gave an excellent active sonar protection as the layer were acting like a reflection mirror. Today the have transmitters at different levels screening the layers horizontally. I had most of my service on board patrolling in the Barents sea but I cannot remember it was very cold.
Tore

[SnakeDoc]

Don,
as Tore said, the heating was primarily electric. The steam heating installation was fitted (I believe) in the early-war U-Boats and abandoned in the end of war. U995 was not equipped with such system.
The steam heaters are visible on these two photos from U570 (below the hatch):


The electric heaters were portable devices, which were plugged to the U-Boat electric net.
One of them you can see on this photo from U570 torpedo room:

I have attached also two more photos of electric and steam heaters.
As far as I know, type IX U-Boats had the same heating installations as type VII.
But type XB mine-layers were fitted with steam heating system, which consisted of steam generators, whose utilized the heat from the exhaust gases.
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Regards
Maciek

[SnakeDoc]

Ah… nice! You assist the pump with pressure from the tank. Where exactly is the exit to outboard for the pump located?

I have attached two photos of the port and starboard side of the boat.
On port there is visible only one hole for inlet/outlet, on the starboard - two.
I have also attached sketch made by Tore, where I marked with blue line one more opening (water inlet).
I suppose, that the "blue one" is the inlet on the starboard side, while the other inlet and outlet - on the port side.


--
Regards
Maciek