Tores mailbox VIIC and VIIC/41 operation and technical details

[VIC20]

I've seen pictures of the Wandtochterkompass in U995 before. Guess they removed it some years ago.

[Don Prince]

Hello Mr. Tore,


I added your photo of the Helmsman on page 300 and uploaded the latest version of Skizzenbuch to dropbox.  It getting very close to being finished once I iron out my problems with the speed controller with Maciek's help.  I updated the speed controller again and we'll see... 


Regards,
Don_

[tore]

Don.
Before you finish the Skizzenbuch, I believe there at least two systems worth while to consider, the hydraulics which include both periscopes operations and the schnorchel, and then  the rudder and hydroplane operation including the emergency mechanical hand operation with clutches. Particularly the hydraulic system have a few intricate details, but both are of course vital to a submarine.
Tore

[Don Prince]

Hello Mr. Tore,


I will start looking into the hydraulics and the control for the rudders and hydroplanes...  I believe the rudders and hydroplanes will be fairly easy to do, but I need to do a little research on the hydraulics...  Thanks for your suggestion.


Regards.
Don_

[VIC20]

I still don't understand it - what exactly is the Skizzenbuch?

[Capt Kremin]

Hi Mark


Direct translation is sketch book, however Don's book is a bit more than what most people think of as a sketch book,


Regards
Jon

[VIC20]

Hi Jon,


I'm german, the translation was not the problem    What I mean is what is the plan for this book?

[tore]

Mark.
I am not sure I know Dons plans, but he explained once the reason for making a skizzenbuch was to have a good understanding of the various systemsketches which in some cases was confusing to him. I guess as time went he seems to end up with a book which is a bit more elaborate than an ordinary Skizzenbuch in the German understanding  and hence the name Skizzenbuch could be a bit misleading .
Tore

[Don Prince]

Hello Mr. Tore,


Since the original Skizzenbuck came from the factory for each boat and covered everything mechanical (34 plates just drawings no information).  I decided to explain the functionality of the content of the plates, and then fill in the other areas as well.  I guess I wanted a book that covered most of the basic systems in the type VIIC U-Boat.  I have about 50 books in my library and they contain about 10% of the information I have in Skizzenbuch. 


Now that I am working on the rudders and hydroplanes, I got to a point where something seems strange...  The BBC controller for the rudder is located on the control room forward bulkhead starboard side, and that makes sense.  If they want to go to port the helmsman pushes down on the left (port) button or plunger (he is facing forward).


The hydroplane operators sit in back of the helmsman and work at the BBC controllers mounted on the starboard wall area.  Here is where I get confused; the gauge towards the bulkhead has readings of 25 to 0 to 35 degrees and the other gauge for the crewman in the direction of the stern, his gauge reads 30 to 0 to 30 degrees.


The stern hydroplane has a range of 25 up to 0 to 35 down degrees.  So it looks like the stern hydroplane operator was sitting forward towards the bow???  That doesn't make sense because that would mean the hydroplane mechanical controls would have to cross each other to control the proper hydroplane.  Is that the way it was actually designed?  Or, If during the restoration the museum people swapped the Hydroplane gauges?


Please advise...


Regards,
Don_ 

[Don Prince]

Hello Mr. Tore,


I believe the U-Boat Museum got the gauges swapped...  See the photo from U-570 attached  Is there a clutch lever to engage/disengage the hydroplane manual hand-wheel.  I don't believe they want the hand-wheel rotating while using the push buttons on the hydroplane controller.


Regards,
Don_

[tore]

Don.
I don`t think the fwd hydroplane indicator is swapped with the aft as the dial is clearly marked Vord. Tiefenruder translated forw. hydroplane.  Further the dial for the mechanical indicator (aluminum disc) goes up to 30 degrees see my photo.
If you look careful at the indicator dial it looks as if it has been erased from half of the 25 degrees markings. On some controlroom photos of the rpm repeater for stb engine (propeller) you can see some of the figures are flaking off. I believe the hydroplane indicator is the right one but the dial might have a textdamage.
Tore

[Don Prince]

Hello Mr. Tore,


I took a very close look at the bow and stern gauges and disks on U-995


The bow gauge has a range of 25 - 0 - 35, and the disk range is 30 - 0 - 40


The stern gauge has a range of 30 - 0 - 30, and the disk range is 35 - 0 - (35) (possibly -can't see it)


It looks like the gauges agree with the disks,  I believe that a manual control could get a greater degree of angle like the manual states for the rudder (33 vs 35 when manually driven).


I have come to the conclusion that the manual would be correct for most Type VIIC U-Boats, and U-996's configuration is correct as well.  The manual covers VII's built by 19.9.40.  U-995 a type VIIV/42 and was commissioned on 19.9.43, so what changed?  All the data seems to match up between the VIIC and the VIIC/42 and there seems to be no difference in length, bean, weight, etc,... 


Could the Atlantic Bow have caused a redesign change in the dive plane angles?  Did the VIIC/41 or any later VIIC with the Atlantic bow require a greater forward dive angle to get the wider bow to submerge, and match the Type VIIC dive characteristics with the narrower bow?


What do you think?


Regards,
Don_

[Don Prince]

Hello again Mr. Tore,


I believe you talked about clutches for the hydroplane manual controls.  I don't believe they would want the hand-wheels moving when operating electrically,  Where are they located?


Regards,
Don_

[tore]

Don.
I am afraid I am a bit uncertain on the hydroplane angles. The overall length of the Uboats having the Atlantic bow is about 280 mm longer than the conventional VIIC  bow. According to Simon it is in addition raised gradually 150 mm from frame 104. This alone is not much for changing the design angle of the hydroplanes. However it could be that the flare of the Atlantic bow could influence the reaction time of the boat due to resistance which again could be compensated by different angle relations in some cases. I have not seen any publication or discussion on this subject, so I have to emphasise it is only an assumption.
Tore

[tore]

Don.
The air operated clutches for the hydroplanes are situated locally at the hydroplane gear disengaging the electric drive and engaging the mechanical drive. The operation is controlled from the controlroom, I assume the clutching valves are situated as marked on my image below close to the hydroplaneoperators. As far as I remember the electric and the mechanical hydroplane indicators are operating in both configurations.
Tore