Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Don.
It is fine, below is Simons excellent drawing with my scribbles showing 3 positions of the Schnorchelmast raising.
Tore

[falo]

Hi Tore,


just another type-seven question. The annotation on the drawing (red circle) stated that the capstan should be removed during war patrols (german: "demontiert bei Fronteinsatz"). Do you know if that is correct resp. if that order was followed? Because looking at u boat pictures or television documentaries many boats had not dismantled the capstans.


Thanks in advance and best regards
Falo

[tore]

Falo.
The capstan was removable, however we usually kept it in place. I believe most of the VIICs removed it during warpatrol. Below is a  photo showing U 278 returning to Narvik Norway 9th. May 1945 from warpatrol having the capstan removed.  I guess many of the photos are shot in harbour and I guess most of the U boats would have the capstan fitted. In the end I should imagine it was up to the CO.to order it fitted or not. 
Tore

[falo]

Hi Tore,


thank you very much for the information.


Regards
falo

[Don Prince]

Hello Mr. Tore,


I believe the electric motor to drive the capstan and the windless wench was located under the floor in the forward torpedo room.  Later the motor was moved to the ceiling to make room for the LUT control panel and lines to the torpedo tubes.   


What part of the capstan was removed and where was it stored?


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


U-278 does not have a KDB showing either...  And I checked some of my other U-Boat photos and some do show the KDB and others don't.  Was it possible to lower it because it was exposed to depth charge damage...?


Regards,
Don_

[tore]

Don
Capstan.
I guess that most of the VIICs had a pneumatic motor situated below the deck between the torpedotubes having a mechanical rod drive up to the capstan gearbox. On some drawings this motor is described as an electric motor, I guess that could be a misunderstanding. Presumeably in the effort to reduce the increased weight of the VIICs/41 the rather heavy drive of this arrangement was substituted by the electric drive shown on U 995. However on most of the drawings including crossections drawings of the VIICs/41, the pneumatic motor and rod drive is maintained. I believe this is a mistake and that all the VIIC/41s had the electric drive, see my images below. It could however be that even the later VIICs got the electric drive as well.
 As we kept the capstan in place all the time, I cannot remember how it was dismantled, I should assume it was just the upper head that was removed and a simple dogclutch or even a square connection to the drive and locking nuts. A storage would probably be under the casing deck were we stored the scepters duly secured as well.
Tore

[SnakeDoc]

Hi Tore,

I guess that most of the VIICs had a pneumatic motor situated below the deck between the torpedotubes having a mechanical rod drive up to the capstan gearbox. On some drawings this motor is described as an electric motor, I guess that could be a misunderstanding. Presumeably in the effort to reduce the increased weight of the VIICs/41 the rather heavy drive of this arrangement was substituted by the electric drive shown on U 995.

Tore, are you sure that U995 was fitted with electric motor? I guess, that the weight reduction was not (would not be) so significant. Let's see: original, pneumatic motor: power 19HP (14 kW), weight 330 kg. Comparable electric motor (driving the main bilge pump): power 20/30 kW, weight 300 kg. I estimate, that weight reduction would be about 100/150 kg. Maybe it would be sufficent...
Moreover, the motor driving the capstan should be (was in case of pneumatic one) controlled from the upper deck. It was done by means of the shaft passing through the pressure hull, which was fitted with the handle. The shaft was driving the air control valve. I don't think that Germans would install the control switches at the upper deck.

For now, I do not have access to my photos, but after weekend I will upload photos of the device, which is (in my opinion) the pneumatic motor with some pneumatic armatures.

Tore, what is the source of the part of your drawing (the white background, with green markings)?

The piece of equipment you have marked with the red arrow (and green color) is the gyro-angle receiver for torpedo tubes. The driving motor (pneumatic in my opinion) is the next to the right (also marked with green color).

--
Regards
Maciek

[SnakeDoc]

Hi Don,

U-278 does not have a KDB showing either...  And I checked some of my other U-Boat photos and some do show the KDB and others don't.  Was it possible to lower it because it was exposed to depth charge damage...?

Not all U-Boats were fitted with the KDB. KDB was more sensitive and accurate than GHG, but it was extremaly susceptible to damage from depth charges and heavy sea conditions. So it was abandoned on the late war U-Boats.

--
Regards
Maciek

[tore]

Maciek.
My arrow to the torpedo gyroangle receiver is wrong and done in a hurry. I am not at all sure about the electric capstan motor Maciek, as I cannot remember. As I mentioned above most of the drawings available shows the pneumatic motor,  in fact all my German VIIC/41 drawings, even those after the war. When I checked with U-historia my bad spanish fooled me as I read el motor as electric motor . I agree with Maciek if you move the pneumatic motor up to the top eliminating the rod drive there will be  no saving of weight with an el-motor .The conclusion, the pneumatic drive is still a fact on the late VIICs as well and all of a sudden I can hear the sound of the pneumatic motor running when we were mooring, sorry about the confusion .
Tore

[SnakeDoc]

Tore,

one more thing - I suppose, that mechanical characteristic of the DC electric motor is quite inappropriate for mooring work and pulling the anchor. I mean, that during these works, the motor can be installed for a long while, which could easily cause its damage.

--
Regards
Maciek

[Don Prince]

Hello Mr. Tore and Maciek,


I apologize for creating a mess....  In my Skizzenbuch the capstan and anchor windless is listed as a pneumatic-motor.  My question was valid about what part of the capstan was removed, but not the electric motor error on my part.


Regards,
Don_

[Don Prince]

Hello Mr. Tore and Maciek,


I corrected the following in Skizzenbuch:
Page 335 - in the drawing top line I corrected a type-o (Fuel was Fueo).
Page 425 - added some info on KDB.
Page 435 - Added info on the capstan.


I uploaded the latest version of Skizzenbuch to dropbox.  I sure hope there are not a whole lot more of my errors.  However, I'm not the best of typist (I use the old hunt and peck system!)...  I know there are people who can type without ever looking at the keyboard, but I'm not one of then.   


When I was working at NCR many years ago, one of my younger co-workers swapped some to the key tops on my computers keyboard.  The next morning, I could not get logged into my system (our screen stayed blank until validated).  Chuck came over and typed my name without looking at the keyboard and my system opened up to the support screen.  Right away I smelled a RAT, and figured out what he did to me...  Come to think about it - that was funny, but not that morning to me!  That afternoon, Chuck needed help with the IBM BIOS vector tables.  I helped him because I don't hold grudges; besides it was to help an NCR field engineer on a customer site and that was our job...


Regards,
Don_

[tore]

Don.
Your update seems OK to me. Don`t bader about creating confusion I am still laughing about my spanish for El motor. As to the finger dancing on the key board, when you are at my age, the nature make sure to use a two fingers dance.
Tore

[tore]

U 278.
The photo of U- 278 returning from patrol to Narvik, Norway on May 9th 1945 remind me of an incident which happened on the surrender of the Uboats in this area. 12 uboats had already returned to the area following 3 more, including U 278, on May 9th. The Western Allied High Command did not like so many advanced highly operational uboats concentrated that high up north, close to the Soviet occupied county of Finmark Norway, they agreed with the Germans to move all the Uboats still with the German COs and crew, flying a black flag,further south to Trondheim. The formidable fleet of 15 uboats, U-294,- 295, -312, 313,- 363,-427, -481, -668,-716,- 968,- 997, -1165, -278, -and -992 sailed on May 16th 1945  southwards bound. The Western Allied High command forgot however to advice the Norwegian Naval High command and one of our destroyers KNM Stord (which participated in the sinking of the German battleship Scharnhorst) was on another mission on her way north meeting accidentally this formidable submarine fleet. This created a dangerous tense situation before the matter was solved by a signal from KNM Stord to the high command. The 15 Uboats were redirected to Loch Eriboll, Scotland as a beginning of the later Operation Pledge e.g. transfer of 97 uboats from Norway to Scotland, ultimately ending later in operation Deadlight.
Tore