Tores mailbox VIIC and VIIC/41 operation and technical details

[VIC20]

Hello again Tore and all others,


what about the telegraphs and audioalarm when running silent on E-Machines?

[NZSnowman]

Tore, we know that the Germans do not used Tab Washers on the internal pipe flanges bolts but used Tab Washers on all pipe flanges bolts that penetrated the pressure hull.

Do you think the Germans used Tab Washers on all the external pipe flanges outside the pressure hull or only on the pipe flanges that penetrated the pressure hull?

[karel]

Hello again Tore and all others,


what about the telegraphs and audioalarm when running silent on E-Machines?

Not sure if i remember correctly but reading the u-boat manual when you were in silent mode there was no audioalarm at all. Only the light was blinking. There was a switch somewhere where you could control this.  3 modes. Off/Audioalarm & light bliking/ blinking only.   I may be wrong. Have been reading so much information that it all becomes a mess in my head  


But in game i this could be a cool extra layer of management. If you forget to manage telegraph switch modes when in silent run and give a new order with alarm then your noise level goes trough the roof and enemy could potentially locate your position.

[tore]

Tore, we know that the Germans do not used Tab Washers on the internal pipe flanges bolts but used Tab Washers on all pipe flanges bolts that penetrated the pressure hull.

Do you think the Germans used Tab Washers on all the external pipe flanges outside the pressure hull or only on the pipe flanges that penetrated the pressure hull?

Simon.
I cannot remember for sure, but would be inclined to think they would use tabwashers or other locking devices on essential pipeflanges like fuel compensatingwater and ventducts.
Tore

[tore]

Karel.
You remembered right, in silent run mode the enginetelegraphs had  switches on the controlbox in the controlroom enabling to disconnect the audible singnal system. In fact we used this system during night not to disturb sleeping crew under normal circumstances. Down below is an image of the control box which I picked from Dons Skizzenbook which I guess comes for sale next year.
Tore

[Don Prince]

Hello Mr. Tore,


While surface running there is an air inlet ventilation stack and an air outlet ventilation stack... I guess the inlet stack is on the Starboard side in back of the tower under the bridge deck, is that correct?


Regards,
Don_

[SnakeDoc]

Hi Don,

While surface running there is an air inlet ventilation stack and an air outlet ventilation stack... I guess the inlet stack is on the Starboard side in back of the tower under the bridge deck, is that correct?

You are right, the ventilation inlet trunk is at starboard side, behind the conning tower, inside the conning tower casing, under the Wintergarten platform.


--
Regards
Maciek

[tore]

Don and Maciek.
The dieselair intake is as you said on stb side and the  large airduct goes  outside the pressurehull to the main dieselair hull  inletvalve. In the engine room it splits in stb and port duct ending at the bordsides behind the engine towards the bilges. Surfaced in bad weather the seawater from the ducts gushed down to the bilges which was the purpose for the design. I once experienced on U 926 KNM Kya after a refit during a testdive we had a severe leakage on the dieselair intakevalve, filling up the whole duct to the hullvalve being shut. The effect was we went down like an elevator and we had to blow all the ballasttanks before we finally stopped at 117 meters.
Tore

[NZSnowman]

Hi Tore,

Any idea that valve 'b' could look like, on Plan 10 : Fuel Oil Compensating System?

http://www.uboatarchive.net/U-570/U-570Plate10.htm

PS. Don have you see any photo's of this valve?

[Don Prince]

Hi Simon,




I don't have a sure answer to your question...  Only an unsure opinion - I have attached a photo as a possibility (Note I highlighted the valve in question). I believe the valves in question are a three way cock with a 'T" plug and a means to limit the valve to only 2 positions...




The image attached seems to qualify for the "b" valve going to FBT 4 port side because it is far enough ahead of the Q Tank. It looks to be low enough to fit into the scheme of things, and it has a means to limit the valve movement.  There is a red metal stake that extends into the valve hand wheel spokes which will limit the valve selection...  Hopefully Mr. Tore or Maciek will have a definitive answer to your question instead of my 'SWAG"...




Regards,
Don_

[NZSnowman]

Hi Don

From what I know valve 'b' is outside the Pressure Hull.

To me the valve in the picture look like a high pressure air valve.

It like you said we will need to wait for Tore or Maciek.

Simon
 

[Don Prince]

Hi Simon,


I believe you should wait for a response from Mr. Tore or Maciek... I was just thinking of a drawing in Skizzenbuch where a valve for the header tank or sea water selection was located at the bottom of the saddle tanks.  If they had to change the selection, then the valve stem would need to come through the pressure hull to change from the fuel oil mode to the ballast mode.

Skizzenbuch -
"The compensating water pipes goes from the header tank to a small chamber (about 1.5 % of the tank volume) at the bottom of the tank, from this chamber a short pipe goes into the tank bottom and an equalizing pipe directly to the sea. The two connections are controlled by a double seated selector valve operated from the casing. The valve has only two positions, either to the fuel tank or direct to the sea. When in the fuel oil tank configuration the Kingstons are shut and the selector valve open to the fuel tank and thus shut to the sea."

Regards,
Don_

[NZSnowman]

Hi Simon,


I believe you should wait for a response from Mr. Tore or Maciek... I was just thinking of a drawing in Skizzenbuch where a valve for the header tank or sea water selection was located at the bottom of the saddle tanks.  If they had to change the selection, then the valve stem would need to come through the pressure hull to change from the fuel oil mode to the ballast mode.


Regards,
Don_

That very interesting! I had always presumed that the valve was under the deck and not in the saddle tank. I have even draw this valve under the deck in my 2-D drawing

Don, have you come across any diameter of the pipes of the Fuel Oil Compensating System? Tore and I talked about this a few years back, and guessed something about a diameter of 75 mm but I am worry if this is too big

[Don Prince]

Hi Simon,


I have no idea as to the pipe diameters...  I only know from what I have learned from Mr. Tore and Maciek plus a little research on my own.


Hello Mr. Tore,


Down like an elevator aye!  And the problem was caused just by water in the inlet stack and the inlet line?  Was Kya equipped with the later Schnorchel where the inlet pipe went crossed-over to the diesel air trunk? If that was the case, then the diesel air trunk above the pressure hull could also get flooded and that extra weight increase would be huge???


Regards,
Don_

[tore]

Simon- Don.
Sorry being late in answering. We  never or very seldom used the fuel mode of the saddle ballasttanks, as we operated the VIICs as Coastal submarines. Hence I have not a personal experience of operating same. Transfering a ballasttank into fuelconfigurating requires some preparation. Of course the ventducts have to be shut, the blowing pipe both HP air and exhaust has to be locked shut, but nevertheless the compensating water pipe is in place and in ballasttank configuration you have to take measures to prevent blowing air into the compensating system.
In the bottom of the external ballast/fuel tanks the compensating water is checked by a selectorvalve D on the plan 8 this valve has two positions either open directly to the bottom of the tank and shut to the sea (fuelmode) or (in ballast mode) via a recess in the tank ( to prevent possible oilspill) to the sea and shut to the tank. My rough sketch below might explain the idea.The selector valve sits on the top of the pipe in the tank like some of the fuel testingvalves but are operated from outside the pressurehull ( not in the controlroom). The system prevent, in ballast mode, that  the compensating system don`t get higher pressures than the head of the compensating expansion tank in the towercasing regardless of the depth of the submarine and is not influenced by HP airblowing of the ballasttank.  Tore