Tores mailbox VIIC and VIIC/41 operation and technical details

[Don Prince]

Hello Mr. Tore,


When I look at the Papenburg depth gauge between the two control stations in the control room, it looks like the gauge is in two parts.  The forward water column looks to indicate the height of the periscope to a point.  Then the aft water column on the right looks to indicate the periscope head/eye at a position above or below the water surface.  Is this basically correct?


The question I have is this gauge is in the control room, and the captain is in the tower working the attack periscope.  Does the captain use/need the Papenburg depth gauge.  I would not think an experienced  captain would need the gauge because he could see when the periscope is above or below the water.


I don't recall any linkage between the periscope pneumatic-hydraulic drive and the Papenburg depth gauge...

Also, what is this device on the other end of the control room.  It is two long tubes with a perforated metal protective covering?  See photo...


The huge 0 - 25 meter depth gauge; what are the reference points? At 25 meters is that to the surface from the bridge, deck, keel?  If it were the keel, then it could never get to 0 meters...

Regards,
Don_

[tore]

Don.
The two long tubes with the metal covering are the level gauges for the port and stb fuel/ regulatingtanks (saddletanks) 1 and regulating tanks 2, you have 2 on each port and stb side.
All the depth gauges shows the depth from the keel bottom to the surface and the large depthgauge to 25 meters was used to navigate at periscope depth.The only time the gauge show 0 was in drydock   It was shut off when going deeper.
The Papenberg depth gauge is important as some time during attack you might have difficulties in keeping stable depth, thus the periscope which should not be too heavily exposed would require a constant adjustment while CO is busy with bearings and other attack parameters. I guess he could leave that adjustment to another periscope adjustment station next to a Papenberg depthgauge. If you look at the hydraulic system for the tower you are able to locate two control levers for the attack periscope one locally at the periscope and one off the periscope having a selectorvalves to choose one of the two. I guess on some of the IX types you had an indicator connected to the winch which gave, combined with the Papenberg, a direct indication of the periscope exposed above the surface. I can`t remember this device on the VIICs.
Tore

[tore]

Don.
The Papenberg depth gauge, named after the inventor, a German naval engineer Heinrich Papenberg (not Papenburg)  is used for a quick response and accurate depth control at shallow depth for different purposes like accurate periscope depth and schnorcheldepth. It is a watercolumn gauge having connection to the sea via shut off valves on one side and a sealed aircushion on the other side. The scale could variy like having a sketch showing the depth in relation to the schnorchel mast floatvalve or the periscope. The sketch shown below shows the navigation periscope position and I think the air inletfloat of a ringfloat schnorchel mast. I guess in the tower it would be the attack periscope.  As far as I remember you had to shut the hullcocks at 18 meter.
Tore

[Don Prince]

Hello Mr. Tore,


I uploaded the latest Skizzenbuch to dropbox and the info on the Papenberg gauge is on pages 183 - 186...


Thank you for all your help!


Regards,
Don_

[tore]

Don-
I have checked your skizzenbuch pages 183 and 186 and have a few remarks. I realize I forgot the inclinator gauge next to the Papenberg, this gauge is called the inclinator and works as you describes, the advantage of this design is that it is more accurate and easier to react on than a conventional air bubble in a curved glasstube. The instrument showing the shaft rpm is called a tachometer. The small manometer next to the 25 meter depth gauge is not the main depthgauge for larger depth, it is a check manometer for the depthgauges. I am afraid somebody nicked the big depth gauge for the larger depth on old museums U 995, but on the photo below you see the depthgauge we used at depth exceeding 25 meters.
Otherwise the pages are OK.
Tore

[Don Prince]

Hello Mr. Tore,


I made the corrections to Skizzenbuch and uploaded the latest version to dropbox,,,


Also, a welcome back to Maciek from his vacation (Holiday), I hope it was pleasant and relaxing my friend...


Regards,
Don_

[tore]

Don.
Your Skizzenbuch checked OK except I believe a few words have been omitted on the deep depth gauge as you state :"  when the submarine is running at depth submerged ...."   It is used for depth beyond 25 meters.
Tore

[tore]

Don.
Direction of propellerrotation.
The opposite direction of the propellerrotation is not unique for a submarine, but counter rotation ( usually outboard rotation) for a twin propeller installation is normal for any ship having twin propellerinstallation. The reason for such a counterrotation is that the torque created by each propeller is neutralised. If both were rotating the same direction, the vessel would drag to one side which  constantly had to be compensated by the rudder and you would have a loss of energy (speed).
Tore

[tore]

Don.
As a professional in electrics I wonder if you have noticed the two way of cabling on the museum U 995. The neat original and the post war type. We have many times warned against copying the details in this submarine as many details are not original. The fluorescent lightning was of course not original as well as the postwar cabletrays running right through the whole interior. In the engine room these trays are an obstruction for pulling a main engine piston and the watertight bulkhead passages are just plain holes as can be seen on my photo below.
Tore

[Don Prince]

Hello Mr. Tore,


Thank you for noting the cabling...  I believe I will add that to Skizzenbuch.  In Addition, Maciek has provided me with a great deal of information after his Holiday and I'm working on that as well.  It will take awhile before the next version of Skizzenbuch is available.


Regards,
Don_

[tore]

Don.
Your Skizzenbuch seems to be a never ending project. Today I just mention a simple yet important detail in the structure strength of the pressurehull. The two torpedoloading hatches creates a large oval hole in the pressure hull which implies a cut of two frames causing a severe weakening of the structure. This is compensated by introducing two strong removeable supportbeams which substitutes the cut away parts of the two frames. Sometimes during a long stay in harbour we used the forward torpedo hatch as an easy access and we removed these beams not just for the torpedoes but even for the crew and guests.
Tore

[tore]

Don.
In your Skizzenbuch page 48 and 49 you state  the measuring tubes for both the regulating tanks 2 and the fueloil/regulating tanks 1 are for measuring fuel in the tanks.
 As you know the regulating tanks 2 port and stb have only water for compensating weight changes, you need that capacity just for regulating water and thus cannot be used for fuel, whereas the smaller fueloil/regulating tanks no 1 port and stb. can be converted to fueloil tanks. The water gauges for both tanks are primarily used for accurate measuring the water contents, but can of course for fueloil/ regulating tanks no 1 port and stb. be used for fueloil measuring as well.
Tore

[Don Prince]

Hello Mr. Tore and Maciek,


I just went through a major update to Skizzenbuch...  I changed the font size (smaller) on the 2 index pages so I could have more entries.  I have made the following updates:


48 - 49  fuel / Water  Per Tore and Maciek
84  Tools  Per Tore
92 - 93  Junkers exhaust  Tore
115  Aux water cooling  Per Maciek
136  Aux lubricating Pump  Per Maciek
183 - 190  Panenberg, Inclinometer, Depth, Tachometer, Telegraph  Per Maciek
265 - 259 Periscopes  Per Maciek
282 Torpedo Tube Hatch  Per Tore
352 - 353 Rotary Converters  Per Maciek
354 Update Rotary Schematic  Per Don_
366 - 374 Propulsion and Clutches  Per Tore


I placed the latest version of Skizzenbuch in dropbox and I do welcome comments...


Regards,
Don_

[tore]

Don.
 I have read through the Skizzenbuch pages mentioned by you and have following remarks.
Page 48-49. Fueloil bunker and regulator tanks 1. You use the expression "air is blown into the pressure hull". You are actually venting the tanks into the control room. As these tanks, when used in fueloil bunker configuration, are not connected to the compensating water system and as such have to have another transfersystem, LP air is used for the transfer. The tanks are vented trough sightglasses and muffler into the controlroom bilge.
Page 4 "T" tools you mention "....have a square socket to fit over the deckdoor screw down lock of the....". Many (most?) of the valves have an elongation of the valvespindle ending in a square up to the deckplates for easy access by the T tool. Thus no "doors" or hatches needs to be opened, see my photo of the engine room and casingdeck.
Page 92-93. As the Junker compressor is a free piston two stroke diesel it is very susceptible of accurate balancing. It is a single cylinder engine, not two cylinder as stated. Having carbon deposits on the opposed pistons due to bad scavenging and combustion creates pistoncarbon deposits (unbalance) and shorten the maintenance intervals, thus increased exhaust counter pressure should be avoided.
May be you should emphasize that the Junker exhaustsystem sketches made by me is an assumption from my side as we have no original drawings of same.
Page 136 Aux. luboilpump. The pump you describe is the fueloil transferpump which can be connected to the luboilsystem and thus used as an auxiliary luboil pump.
Otherwise  I enjoyed quite a few interesting, unknown to me, photos- Macieks ?
Tore

[VIC20]

Tore, look at this lol: https://www.youtube.com/watch?v=MzA1brBuhFc