Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Don.
In order to have a better overall picture I post two of Falos photos which shows the electronic boxes as well.
Tore

[Don Prince]

Hello Mr. Tore,


Thank you for all your time and effort in helping me understand the drawings.  If you don't mind; I believe I will use your method of overlaying actual photos on the Plate prints.  That's an excellent means to demonstrate a point and it will make my Skizzenbuck much more impressive to view...


Kind regards,
Don_

[tore]

Don.
I Guess the Q-tank system is not Complete without your indication of the Kingstones valvespindles which in some cases can be hard to localise. The Q-tank Kingstonespindles are the second spindles from forward bulkhead as shown on the photo below. As previously told the handles are cranks which are removed when not in use.
Tore

[SnakeDoc]

Hi Gentlemen,

Tore, I think, that the spindles you have marked on the photos are the drive shafts for the flood valves of the Tauchbunker 4. This topic was discussed here:
http://models.rokket.biz/index.php?topic=106.msg9585#msg9585

The valves you have marked are (in my opinion) for blowing Tauchbunker 4, getting fuel and sounding the tank.
Shaft drives of the Untertriebszelle flood valves are located further aft - near the attack periscope shaft (see the attached photos).

Regard to the hull valves of the Untertriebszelle - also see photo.
What do you think Tore?

--
Regards
Maciek

PS. Welcome to the forum, Don. You did not answer my email

[tore]

Don.
It is always good to have a watchdog like Maciek, particularly when you make a hasty conclusion like I did  in my eagerness to find a system matching you plate17b. Maciek is right, the Q tank is placed on both sides of frame 45 slightly ahead of the attack periscope casings centerline. Thanks for the correction Maciek, I was too quick. Maciek is introducing a solution to the Kingston which I believe is correct, further a blow/ venting solution which I am afraid would put your plan 17b on hold and back to good old plan 17.
You suggestion of the blowing/ venting of the Q tank seems to me to be correct Maciek. Some thoughts which backs up Macieks suggestion. Apart from the obvious placing of the Q, the use of same would indicate Macieks  arrangement suggestion is correct. Q is used as a quick diving tank which mostly is needed in emergency situations like crash dives avoiding ramming, collisions or depthcharging as such it has to be easy and quick to operate and placed close to the voicepipes. So I guess Macieks photo " untertriebzelle" is a good reference to use together with plan 17. As many times before together we find the correct solution
Tore

[Don Prince]

Gentlemen,


I really appreciate all the help in locating photos of the Negative Buoyancy Tank control devices in the control room.  I found a photo on the internet which looks to be the Kingston valve wheel on the other side of the control room.  It looks to be the round black wheel, am I correct?


Regards,
Don_

[tore]

 ;Don.
This time I have doublechecked with the frames you can be sure this is the wheel for the port Q-tank Kingstone, you see the both on my bad photo below. I am still curious to know from where you got the plan 17b.
Tore

[Don Prince]

Hello Mr. Tore,


I wish I had a clue as to where I downloaded that Plate 17 (I renamed it because I had other Plates from the uboatarchice.net).  [size=78%]Today I looking into the functionality of the Main Pump and The Trim Pump.[/size]
[/size]
[/size][size=78%]The main Pump -  The manual states it's a reversible pump...  However, I seem to get everything to function properly with the pump running in one direction by utilizing different valves to provide pressure or suction.  Am I missing something?  I will post a photo of the mail pump and could you point out how the pump is reversed and why?[/size]
[/size]
[/size][size=78%]The Trim Pump -  I believe I understand how it works.  I will post a photo of the pump and could you post a good photo of the Trim Controller.  [/size]

[Don Prince]

The Main Pump

[SnakeDoc]

Tore,

regarding to the "plan 17b" - I was able to find its origin - it comes from "U Bootskunde für U Boote Bauart VII C", which translated version is published on uboatarchive.net - which was issued on 15 July 1940.

"Skizzenbuch fur das Maschinenpersponal" coming from U-570 and published on uboatarchive.net, which contains "plan 17" - was issued March/April 1941.

I think, that this explains differences.



Tore, there is one more thing, that makes me wonder. On the "plan 17" are marked four Druckunterschiedmessers - pressure differential gauges for the regulating tanks Regelbunker 1 Bb/Stb and Regelzelle 2 Bb/Stb. They show pressure differences between the external sea water pressure and inside the tanks - what is useful when fine flooding and blowing regulating tanks. Their are also used for operations described in Tauchvorschrift ( http://uboatarchive.net/DivingRegulations.htm ) - paragraph 155, 163, 185

These four gauges are gathered on the control panel above the blowing ballast tank distributor (see photo - on both sides, in the middle - pressure gauge of the main blowing valve).

In the control room of U-995 are two more differential pressure gauges - near Untertriebszelle blowing lines' hull valves. These gauges are not drawn on the "plan 17", but are mentioned in the British report on HMS Graph (table on the page 39 - http://uboatarchive.net/U-570BritishReport.htm ). 

The purpose for these gauges I have found also in Tauchvorschrift - paragraphs 131 - 133.

Reading these paragraphs I'm wondering about "residual water check" (Restwasserprufen). It became obvious to me, that main problem while blowing Untertriebszelle is to stop blowing just before they are emptied - to avoid escaping of compressed air bubbles through the bottom flood valves. For this reason, the residual water check lines were applied. But I can not imagine how they worked. Could you put some light on this topic Tore?

--
Thanks, regards
Maciek

[SnakeDoc]

The main Pump -  The manual states it's a reversible pump...  However, I seem to get everything to function properly with the pump running in one direction by utilizing different valves to provide pressure or suction.  Am I missing something?  I will post a photo of the mail pump and could you point out how the pump is reversed and why?

Well, in the original text the term is: "selbstansaugende, umschaltbare 2-stufige Kreiselpumpe". I translated umschaltbare as reversible, but it rather should be switchable. Switchable - that means that pump's two stages can be connected parallel or in series - for great capacity and low head or low capacity and high head respectively. The switching took place by control valve.

The Trim Pump -  I believe I understand how it works.  I will post a photo of the pump and could you post a good photo of the Trim Controller.

I have attached photo of trim controller.

--
Regards
Maciek

[tore]

Maciek.
Thanks for you spotting of the source for plan 17b.
Your observation on the differential manometer is correct. I assume the following: The local placed differential manometers for the Q is required for a good monitoring of the diff pressure not exceeding 2 bar. being the max allowing diff pressure. The normal procedure for using Q is, if you have time, to open the Kingstons (and inboard venting) filling the tanks while surfaced, then you are about in excess of 4 tonnes heavier than normal surface condition. In the event of crashdiving, you open the normal ballastvents, this Q weight speeds up going through the surface and at about 10 meters the hydroplanes and trim of the submarine take over the further diving. Depending upon the diving angle, E-motorspeed (and depth) the order blow Q is given and Q is blown by a diffpressure below 2 bar. The water residue checksystem is a small pipe going down to the Kingstons and an internal cock in the CR ending into a small funnel, I believe you can see same on the photo of the port system. At the blowing of the Q the testcock is open and seawater is pressed out until the waterlevel is slightly above the Kingston openings, then the blowingair enter the residuewater testline before it reach the Kingston opening, air comes out of the testcock and the order stop blowing Q is given, and the Kingstons are shut. Sometimes both tanks are not emptied at the same time and you have to shut the blowing hull valve of the empty tank before the other, that is one of the reasons you have two separate "controlstations" for the Q. I have tried to make a sketch showing how I assume the system works. I hope I have understood your question correctly.
Tore

[tore]

The main Pump -  The manual states it's a reversible pump...  However, I seem to get everything to function properly with the pump running in one direction by utilizing different valves to provide pressure or suction.  Am I missing something?  I will post a photo of the mail pump and could you point out how the pump is reversed and why?

Well, in the original text the term is: "selbstansaugende, umschaltbare 2-stufige Kreiselpumpe". I translated umschaltbare as reversible, but it rather should be switchable. Switchable - that means that pump's two stages can be connected parallel or in series - for great capacity and low head or low capacity and high head respectively. The switching took place by control valve.

The Trim Pump -  I believe I understand how it works.  I will post a photo of the pump and could you post a good photo of the Trim Controller.

I have attached photo of trim controller.

--
Regards
Maciek

Maciek
Trimpump.
You are of course right. As a further comment to this pump, the trimcontroller was very much in use. Prior to shifting of some weighs inside the submarine you pumped water from forward to aft or the opposite. One of the most used order from the officer on watch was: pump 400 liter from aft to forward, then you knew it would be followed by : diving station!. It happened people were on their station before the latter order was given. The weightransfer was necessary as quite a few people lived in the fwd torpedocompartment and had their divingstations in the CR.
Tore

[tore]

Don.
I don`t know if you got the working of the "Trimschalter" OK so I made a sketch showing how it works in the trimpumping mode, ballastwater from forward tank to aft and the opposite. Please note that the trimpump is a piston pump, the airvessels can be clearly seen in the front, whereas  the main bilgepump is a two impellers centrifugal pump where the impellers can either be run in series or parallel as Macieck says.
Tore

[Don Prince]

Hello Maciek,


I looked at the photo closely and it looks like there are 5 pressure gauges (one under the red hand wheel) clustered around the main blowing valve.  Would that be a pressure gauge for each dive tank 1 through 5?

In addition, on your photo labeled "untertriebszelle gauges"  The large red hand-wheel is for one or both Negative Buoyancy tanks?  I don't see the same configuration on the other side...


Regards,
Don_