Author Topic: Tores mailbox VIIC and VIIC/41 operation and technical details  (Read 576700 times)

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Offline Don Prince

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #1995 on: 10 Jul , 2014, 22:52 »
Thanks Maciek,


A/C didn't sound right, but it was spelled out on Plate 18: Air Conditioning Unit... So, these would come into use when the U-Boat is submerged and they are re-circulating the air inside the pressure hull???


Regards,
Don_
« Last Edit: 10 Jul , 2014, 22:58 by Don Prince »
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Offline SnakeDoc

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #1996 on: 10 Jul , 2014, 23:12 »
That's right, Don.


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Maciek

Offline tore

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #1997 on: 11 Jul , 2014, 00:25 »
Thanks Tore, I still have some question about the flooding & drainage installation:
- The water inlet, I guess it worked with the natural water pressure and you don't need the pump at all to flood the regulating tanks right?
- Is the diameter of the (water) pipes of the flooding & drainage installation identical to the ones used to blow out the tanks with compressed air?




Mark.
Surfaced, the filling of the regulatingtanks could be done by natural seawater pressure only up to the draugthline of the submarine, submerged of course all the way. I Guess the fine floodline to the distribution chest has a smaller diameter than the other pipes and as you use the latter lines for moving the water being pumped or blown I migth have misunderstood the last part of your question.
Tore

Offline tore

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #1998 on: 11 Jul , 2014, 01:38 »
Thanks Maciek,


A/C didn't sound right, but it was spelled out on Plate 18: Air Conditioning Unit... So, these would come into use when the U-Boat is submerged and they are recirculating the air inside the pressure hull???


Regards,
Don_
Don.
In addition to Macieks answer. The CO2 absorbent canisters fitted in ventilation system were a kind of old fashioned scrubbers filled with soda lime granules as reactors. They produced heat and had a non reversible chemical reaction thus a limited lifetime and was only used at a prolonged submersible situations. The procedure at long dives without schnorchling was every man not absolutely needed goes to bed using as little air as possible. The after say some 24-30 hours it became uncomfortable as the CO2 became excessively high and you connected the "scrubbers". The excessive CO2 created a heavy panting and when the "scrubbers" worked the situation became better, then after a while you got problem with the  reduced oxygen and had to connect the oxygen flasks to the ventilation system.
Anyhow contrarily to today, the system was in use only very seldom, I believe in my time we used it once or twice a year. We did not use any sophisticated systems for monitoring the air quality, only experience.
Tore

Offline tore

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #1999 on: 11 Jul , 2014, 02:37 »
Don.
Ventilation shaft hullvalve and selector slide.
Below is the best photo I have, showing the ventilation hullvalve and selector slide in one housing.
Tore
« Last Edit: 11 Jul , 2014, 02:40 by tore »

Offline SnakeDoc

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2000 on: 11 Jul , 2014, 03:38 »
We did not use any sophisticated systems for monitoring the air quality, only experience.

When on 7th May 1945 La Rochelle was surrendered to Allies, they captured decommissioned (but still afloat) U776 (type VIIC U-Boat).
The boat was overhauled and commissioned into the French Navy, where was named Laubie. She was in Service till 1961. She had three accidents:
- on 17th July 1950, during the exercises near the Morocco coast, during surfacing she was rammed by frigate La Surprise (ex HMS Torridge)
- on 2nd May 1960, near Alger, she was rammed on periscope depth by passenger liner Ville de Marseille
- on 22 September 1961 she was rammed (also on periscope depth, when schnorcheling) by submarine Espadon

Laubie also took part as a support for submarine La Creole during the Suez Crisis in 1956.
In 1958, her commander was lieutenant Bernard Louzeau, who (9 years later) became commander of first French nuclear sub - Le Redoutable.
Anyway, till 60s, French submariners also did not have any sophisticated systems for monitoring air quality. To deal with this problem, they took aboard small dogs.
Due to their small size and weight, the dogs reacted quickly on the air quality changes. When the dogs became lethargic - the air purification measures were taken.
On the board of Laubie, there was cocker spaniel name Folk. The dog loved retrieving the bottles, which were thrown away overboard by crew.

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Maciek

Offline VIC20

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2001 on: 11 Jul , 2014, 04:44 »
I guess Laubie Folk had some influence on how often they were surfacing… 3 times a day :D …poor conning tower
« Last Edit: 11 Jul , 2014, 05:32 by VIC20 »

Offline tore

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2002 on: 11 Jul , 2014, 05:04 »
Maciek.
We did not have any dogs, I Guess I would rather copy the miners using a canary bird. However we got the experience of foul air on the body and f.i. allowing one cigarette ( stupid) pr man. If the match did not lit, we were short of oxygen. ;D
We had in fact some cooperation with the French exchanging ideas how to run a VIIC, a couple of our officers were on board one of the french VIICs for a few days I guess this was back in 1951-52.
Tore

Offline SnakeDoc

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2003 on: 11 Jul , 2014, 05:18 »
I will quote circumstances of the last Laubie accident. On 22 September 1961 she served as the target for newly developed homing torpedoes. She had to schnorkeling, while Espadon had to detect her and attack with torpedoes. Commander of Espadon wanted to take up the position behind Laubie stern. He detected her and estimated her course visually - through periscope, using the relative position of the Laubie snorkel head and periscope. But he forgot, that Laubie Schnorchel was (unlike in case modern subs) in front of periscope. And so he took up position in front of Laubie.

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Maciek

Offline VIC20

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2004 on: 11 Jul , 2014, 11:08 »
Tore, when you fill a tank with the flooding & drainage installation where does the air which is already inside the tank move to?


and when you pump water into a tank is there a back pressure valve in the line (between the pump and the tank)?

Offline tore

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2005 on: 11 Jul , 2014, 11:47 »
Mark.
Venting of the reg.tanks and Q.
 The Q as well as the regulatingtanks 1 and 2 port and stb have an inboard venting with sight glasses all ending in a muffler down at the controlroom bilge. The pipes and muffler from the regulating tanks 1 and 2 are fitted on the aft side of the attack periscope housing in the controlroom as seen on the sketch below.
Tore

Offline Don Prince

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2006 on: 11 Jul , 2014, 22:41 »
Hello Mr. Tore,


What is the function of the black and red handles near the Main Pump?


See photo -


Regards,
Don_
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Offline tore

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2007 on: 12 Jul , 2014, 00:06 »
Don.
On valves having difficult access you have extensions of the valvespindle to the handle.On your photo the black handle has an extensionrod which ends in the air, I guess it could be meant for the suction valve for the main bilge pump. The red handle is a seawater board handle with extension to a board valve hard to identify right now. I`ll return when I get the answer.
Tore
« Last Edit: 12 Jul , 2014, 08:40 by tore »

Offline VIC20

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2008 on: 12 Jul , 2014, 05:19 »
Thanks Tore.


Maciek do you also know the diameters of the different (air and water) lines of the flooding and drainage installation?

Offline Don Prince

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Re: Tores mailbox VIIC and VIIC/41 operation and technical details
« Reply #2009 on: 12 Jul , 2014, 18:59 »
Hello All,


It was stated that D2, D3, and D4 was the ballast system...  Could we include the Negative Buoyancy tanks in that category as well?


Regards,
Don_
A man's got to know his limitations...
Harry Callahan, SFPD