Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Simon.
I guess more like the box below.

Tore

[NZSnowman]

Would the packing be wood?

[tore]

Simon.
I don`t think so Simon, wood like Lingnum Vitae is usually used in heavy loaded rotating shafts having submerged bearing like propeller shaft. For smaller spindles like valvestems etc having reciprocating movements stuffing fibers like shown below are cut into excact length to fit the circumference of the shaft, you don`t wind it around but each "ring" are separately placed on top of the other having the cut on different place for each ring. The fibermaterial could be of different materials, even asbestos and "impregnated" with graphite. Having a lantern ring between the two stuffings allows grease to be injected both for sealing and lubrication of the reciprocating shaft.
Tore

[tore]

Simon.
Knowing your likings for small details here is the greasing details. The greasing of the stuffingboxes was done by a grease gun to one common grease nipple serving two stuffingboxes as shown on the image below.

Tore

[tore]

Simon.
You are a snowman getting you master on snow, make a living working with the snow on the southern hemisphere and going into your winter season,we are in my part of the world still figthing to get rid of the thing. We still have snow which shall last for months. Below is an image taken last week from the highway between our two major cities Oslo and Bergen crossing the mountains. The snow is still up to 11 meters and yesterday they had to dig out one of the skiing slopes as they couldn't find the skilift. So if you need practice come to this area.
Tore

[Don Prince]

Hello Mr. Tore,


Why don't they ship some of that snow to the US West coast?  California is rationing water use right now; Maximum 10 minute shower and 1 per day per person, and the lawns are not to be watered/just burn out.  The population kept on increasing and the environmentalist would not let then build water reservoirs because there was a smelt (snail darter) found down stream that was endangered 25 to 30 years ago.  Last year they found one snail darter in the entire river basin that dumps into the pacific Ocean.  Now about 75% of the Sierra snow melt dumps into the pacific Ocean while California burns out...  This country is all screwed-up with environmentalist and political correctness idiots gone wild!


Regards,
Don_

[tore]

Don.
Our dams are overfilled and all the snow would create an unbelievable flooding with spectacular waterfalls and possible damages. When all that meltingwater is ending up in the fjords it creates an interesting situation from a submariners point of view as numerous of layers of water with different salinity is acting like an Asdic mirror,a dreamarea for a submarine CO to exercise and practise hide and seek play.
Tore

[VIC20]

Tore,
I'm still here 
There was a gap between the periscope tube and the opening hole/shaft (the open tub like thing on the bottom of the command room) when the periscope in the command room was retraced right?


I guess it is hard to explain but could you describe the sound of both periscopes?

[VIC20]

I forgot that I can quickly show what I mean 

[Don Prince]

Hello Mr. Tore,

Reviewing the text for:

GW Sequencing…

First you open the main starting air supply valve to admit starting air to the cylinder starting valves and the starting air manifold. Then you move the starting handle to start, on a direct reversible engine you pass the "umsteuer" maneuvering position; the run position and nothing happens. The run position is only the venting valve open the others shut. On the maneuvering position, the starting lever has to stay in reverse position in order to start the reversing process.

When the starting handle is in the start position, air is admitted to the top piston on the cylinder starting valves; pushing the rocker arms down to engage the rollers on the starting cams. On direct reversible engines the cams are selected by the ahead/astern handle and the engine start to run on air. When you obtain the proper revs you move the handle to "betrieb" or "run" the valves supplying air to the "umsteuer" mechanism and top of the cylinder starting valves are shut, and the vent valve on the air manifold opens and the spring under the top piston on the cylinder starting valve forces the piston up lifting the starting valve rollers from the camshaft.

Everything makes sense to me except the first paragraph, and the next to the last sentence -- "The run position is only the venting valve open the others shut."  Could you clarify this sentence?  What others shut?


Regards,
Don_

[tore]

Tore,
I'm still here 
There was a gap between the periscope tube and the opening hole/shaft (the open tub like thing on the bottom of the command room) when the periscope in the command room was retraced right?

Mark.
It is indeed an open space between the periscope well and the navigation periscope, however on the museum U 995 they put a cover on the well.
Tore


I guess it is hard to explain but could you describe the sound of both periscopes?

[tore]

Don.
Would the sketch below give you an explanation? The distribution air manifold with valves is encircled in red and showing the valves in run position.
Tore

[SnakeDoc]

Hi Mark,

There was a gap between the periscope tube and the opening hole/shaft (the open tub like thing on the bottom of the command room) when the periscope in the command room was retraced right?

See attached picture, presenting the control room of HMS Graph (ex-U570). You can see the periscope lowered into the periscope well.

I guess it is hard to explain but could you describe the sound of both periscopes?

Here you can hear the sound when operating the periscope on USS Pampanito (Balao class submarine):
http://archive.hnsa.org/sound/pampanito/periscope.mp3
Her periscopes were also raised and lowered hydraulically.
It sounds quite similarly to the periscope sound in the Das Boot movie.

--
Regards
Maciek

[VIC20]

Thanks, I know this graph picture but I totally forgot to look on it. 

[tore]

Mark.
The sound picture of the periscopes for a VIIC is slightly different and may be variable. The hydraulic system has three large accumulators storing the hydraulic energy and prior to any planned attack this storage was filled by IMO pumps which usually was not necessary to run during the attack, sound picture no 1. The sound picture for the navigation/air periscope is that of an IMO pump running as a motor operating a winch via a geardrive. Sound picture no 2. all told not very high. The attack periscope has two sounds, that of lowering and raising the periscope (very much the same as for the navigation periscope) and the turning of the periscope including the operator which is controlled by foot pedals of the operator and driven by an IMO pump running like a motor via gear assembly. As far as I remember slightly more noisy than the lowering/raising sound and a bit more "whining". Sound picture no 3.
Otherwise I agree with Maciek, may be the movie " Das Boot" gives the best indication.
Down below is the present day U- 995 controlroom with navigation periscope well covered.
Tore