Tores mailbox VIIC and VIIC/41 operation and technical details

[maillemaker]

Hello Tore!

I joined this forum so I could say "hi" to you and to say thank you for participating in this forum and thread to tell us what it was like operating a German u-boat!

Steve

[tore]

Steve thanks, if you have any questions, shoot I am going on 88 so don`t hesitate !
Tore

[maillemaker]

Hi Tore!

Thanks!  To be honest, one of the reasons I jumped in here so quickly when I discovered this thread was to be able to say hi and thanks before you were gone!  I am 46 years old and over the years there have been so many people of historical note that I wished I had had a chance to speak to that were gone before I realized I had the chance to do so. 

For example, I have been trying to get an address for Rienhard Hardegan, who is like 103 years old and supposedly still resides in Bremen, to send him photographs of the Silent Hunter 5 u-boat simulation program, to show him what people are up to these days in remembrance of their deeds of long ago. 

I have long been a fan of the Silent Hunter series of PC uboat simulations, having played them for a decade or more now.  Plus other uboat sims before that.  I have just now undertaken building the Revel VIIC/41 Atlantic Version and so have been inspired to hunt down internet sources for ideas.

I have opened up the long flood opening above the saddle tanks and am adding ribs as many modelers do.  I want to replace the "box" around the snorkel recess area with appropriate deck support structure.  Are there any pictures that show this area of the uboat without the decking in place?

I am slowly working through this long thread - I am on page 8.  Sadly many of the referenced links and even attached pictures no longer work.

Thanks and nice to meet you,
Steve

[maillemaker]

Another question:

On many models, and on the U-995 museum ship, at the point of the saddle tanks is shown a "drip rail" with holes just above it for draining.

It would seem to me that this would be underwater at all times while the boat was in service.  Is the drip rail something added after permanent dry-docking?

Steve

[tore]

Steve, do away with the gutters installed on the museums U 995 they were of course not on the original. Reverting tomorrow with the schnorchel details in the casing, do not copy the museums U 995.
Tore

[tore]

Steve.
Recess for schnorchel mast. I dont think you should make a box for the schnorchel recess. I have seen a couple in the IXC casing. just a box around the schnorchel head, made of plain thin steel plates having drilled holes, I can`t remember we had such a box. When the schnorchel mast was lowered, it rested on cradles fitted on the pressure hull, right above the COs cabin you had a lockingclamp entering an eye on the mast. The clamp had a spindle going into the top of COs cabin ending in a handle to lock the mast in resting position. Otherwise the space around the mast was pretty empty just surrounded by angled thin steel girders and steel supports for the casing and wooden deck.
 The raising cylinder and crank was quite different from to days museum U- 995 mock up as can be seen on my image below. The whole thing was half way above the casing deck. As a bonus I post an mage of me inspecting the original schnorchelmast of KNM Kaura ex. U 995 some time in 1953.
Tore.

[karel]

Thanks. I think got enough out of it (after reading carefully 5 times) in order to figure out how to fit a simplified version to the game. So i have been trying to research about all the valves that are located in command room. We have most of them modelled out in game and i would like to know what did they do so i could give them a right functionality.

This is from my research from all various sources. Sometimes they conflict badly and they are probably wrong.

On screen1
1) Flood ballast tank2 stb
2) Flood ballast tank2 port
3 and 4)  No idea. Something to do with oxygen?

On screen2
1,2,3,4 Somekind of emergency flood crank to quickly fill up tanks. I think one of them were MBT3 or MBT4&2
5,6 - Valves to close/open air intake pipe that goes into engine room? The one that almost caused a serious accident on your patrol when someone forgot to close them and added 5 tons of water when the boat was diving.

Again, many many thanks. For these past few weeks i gathered more information from you than any other source where i did research for months.

[maillemaker]

Recess for schnorchel mast. I dont think you should make a box for the schnorchel recess. I have seen a couple in the IXC casing. just a box around the schnorchel head, made of plain thin steel plates having drilled holes, I can`t remember we had such a box. When the schnorchel mast was lowered, it rested on cradles fitted on the pressure hull, right above the COs cabin you had a lockingclamp entering an eye on the mast. The clamp had a spindle going into the top of COs cabin ending in a handle to lock the mast in resting position. Otherwise the space around the mast was pretty empty just surrounded by angled thin steel girders and steel supports for the casing and wooden deck.

So basically the floor of the "box" is just the top of the pressure hull, right?

In this version of your photograph, which I found in Foxbat's build thread, you can see a little bit more of the snorkle.

It appears that there might be some kind of platform that the snorkle is lying on elevated just slightly above the pressure hull?

[tore]

Karel.
It is not easy to go into valve and vent details in the control room. I am afraid you got it a bit wrong. May be we should go back to the basics. What makes a submarine dive are the main ballast tanks, they are therefore controlled from the control room. For a VIIC you have 8 main ballasttanks MBT1, 2 port and stb. 4 port and stb, MBT 3 which is having a central bulkhead making it port and stb although it is basically the same tank and MBT 5. At the same time we have two buoyancy tanks situated in the bow and the stern. They are not considered as ballast tanks as they are originally designed to give extra buoyancy on the surface to reduce pitching, nevertheless they have to be vented when diving, so you have to open the buoyancy tank vents as well. Contrary to many other submarines the VIICs was  equipped with mechanical operated vents , and when you would have the controls in the control room this means that the forward and aft vents had to be operated by long rod transmissions  going through bulkheads and compartments. A cumbersome arrangement which require a lot of maintenance and greasing. Below I have made a drawing using one of  Simon Morris excellent images as a base in order to explain what I am trying to say. Hopefully the image and text shall give you the answer. Unfortunately I had to split up the drawing as the file is too large. Just ask if something is unclear.
Tore

[tore]

Karel.
I realize the residue air might be a bit unclear. When you have a steep angle bow down diving , it is difficult to vent the aft MBT 2 port and stb as air would be trapped in the aft part of the tanks, colored yellow on my sketch below, hence an extra venting pipe ( yellow) and a common port and stb vent for the aft part of the tanks, operated by a long rod from the control room.
I forgot your assumption on the smaller bulkhead wheels, this has nothing to do with the diving, they are the shut off bulkheadvalves for stb and port ventilation ducts.
Tore

[tore]

Steve.
Schnorchel mast recess in casing. Below is an image showing the original U 995 execution VII/C 41 of the schnorchel with locking pin in lowered postion as well as raised.
Tore

[tore]

Karel.
Finally, your screen2. You are right in your assumption as to valve 6, this is the diesel air supply main intake valve going via a pressure proof duct outside the pressurehull to the board valve in the engine room ending near the bilge on each side of the diesels. The smaller wheel is for the ventilation system going in the same way to the ventilation intake valve and ventilation fan in the engineroom. The reason for having two air intakes is the diesel air system was susceptible to seawater flooding in bad weather hence the outlet ending in the engine room  bilges, a complete separated system with ample draining was used for the ventilation system to prevent seawater penetration and damaging the electric fan motors.
Tore

[karel]

Tore.
Just to make sure i understand right. The "long rod transmission"  this means these rods (1,2,3,4) that are on the upper hull on screen2?

I hope that i am getting this right.  The rods number 1 and 3 are for opening vents for MBT 2&4 port and stb. The rods 2 and 4 are opening MBT3 port and stb.

[tore]

Karel.
I am afraid, not these are pull down handles for MBT 3 stb and port, the long rods for mechanical opening of the forward and aft vents are indicated on the image below.
Tore

[karel]

Thank you for explaining the rods. Now i understand the context better and am able to fully understand your description.


Do you have pictures of handwheels for aft buoyancy tank?
I am also unable to locate the handwheels for negative buoyancy tank port&stb. If i am not mistaken then these tanks itself should locate between regulating tank and MBT4. I guess their handwheels should also be in command room somewhere.