Author Topic: Tores mailbox IX C and IX C/40 operational and technical details  (Read 3947 times)

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Offline Rokket

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A new, extra Tore's Mailbox for IX C and IX C/40 operational and technical details
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Offline tore

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I hope we shall have an interesting discussion around the difference between the two types VIIC and IXC, and welcome Dons input.
Allthough the IX type was developed simuntaneously with the VII type both having roots back to the WW1 submarines, they were designed for different purposes, type IXC being the long distant counterpart to the medium range VIIC and the command boat for the wolfpackleader. In addition some of the IXs was in the latter part of WW2 converted as supply boats,"Milchkuhes" for the VIICs.
 The IXCs had one more torpedotube than the VIICs but I guess the VIICs was a better attack boat as the divingtime was considerably quicker than the larger IXCs which took its toll when the allied airsuperiority became a problem.
Below is an image of a IXC moored together with a RN T class (two midship aft torpeotubes) and the RN A class originally designed for the Pacific.
Tore
« Last Edit: 31 Jul , 2016, 03:40 by tore »

Online Don Prince

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Hello Mr. Tore,


I am reviewing the trim system on the IXC and everything looks very familiar except for item a3 which is a change-over cock but no central passage way?  I marked the item on the attached drawing.  Now back to the basics:


a3 - is the change-over cock
e   - is the main control valve
m  - is a spring loaded pressure valve


When the pump man turns the main control valve (e) to pressurize the trim tank he can monitor the air pressure in the line when viewing the pressure gauge.




1. Is the main control valve (e) used to adjust the amount of air pressure in the line?
2. If the air pressure in the line exceeds the limit set by the pressure valve (m), then will the excess air pressure be vented into the pressure hull?


Regards,
Don_ 
A man’s got to know his limitations…
Harry Callahan, SFPD

Offline tore

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Don.
The plan you are referring to is the LP system,practical identical to the IIVC system. As you know there are two ways of adjusting the trimsystem, normally by the trimpump or by LP air. Using the trimpump implies operating a closed system eg. the air and water volume is constant. When you pump the water to the aft tank the equivalent volume of air is replenishing the watervolume in the forward tank via the LP blow/vent pipe. In that case the LP air pipe is used as an "airshifting" pipe and the enclosed air is free flowing through a central bore of the aircock whereas the LP air connection is shut, you add nothing to the system.
If the trimming is carried out by LP air, you add air to the system as you turn the trim cock to put the required trimtank under pressure and simultaneously the other tank has to get rid of the excessive air to accommodate the receiving water and is vented via the cock and funnel to the bilge. The water is controlled by the trim valve and the water meter as normal. As you normally don`t want to change the amount of water used for trimming, you check the air cock for possible water in the funnel indicating when the receiving tank is full.
As you see, the central bore for the air cock is not drawn neither on the plan for the VIICs or IXCs, on the trimlineplan for the VIICs however you see the bore clearly marked, I assume you`ll find same on the trimline plan for the IXCs.
Tore

Online Don Prince

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Hello Mr. Tore,


I believe the Germans copied an error and promulgated it in their drawings...  On the type VII drawings the TRIMMDRUCKLUFTSCHALTER item (g1) on the Lenz -und Trimmanl drawing looks to be the exact same device TRIMMDRUCKLUFTSCHALTER item (d2) on the Nd luftanlage drawing, but they are not drawn the same???  Both should be a change-over cock with a central passage.



Item (g1) looks to be drawn correctly... Perhaps, it was added to the Type VII drawings and missed on the Type IX drawings.  I have attached the Type IX Trim drawing which does NOT have an air line going to the trim tanks...


Regards,
Don_
A man’s got to know his limitations…
Harry Callahan, SFPD

Offline tore

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Don.
When you have two systems interconnected like LP system connected to the trimsystem I guess you would have a certain individual judgement as to the details you should include on the systemsketch. The people making the VIIC sketches thought it was a good idea, as I would have done, to include the equalizer line on the trimlinesystem, the IXC people was of the opinion that same line belong to the LP system. Nevertheless I am inclined to maintain the central passage in the changeover cock for both IIVC and IXC types.
Tore

Online Don Prince

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Hello Mr. Tore,


I agree with what you stated...  The Type IX should have the change-over cock with the central passage!


Regards,
Don_
A man’s got to know his limitations…
Harry Callahan, SFPD

Online Don Prince

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Hello Mr. Tore,


I added the Trim vent line and valve to the drawing and translated the German to English on the page... Does it look OK to you?


Regards,
Don_
A man’s got to know his limitations…
Harry Callahan, SFPD

Offline tore

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Don.
I guess it is OK but may be you should use the correct icon for the central passage chageover cock , a singel line instead of double.
Tore

Online Don Prince

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Hello Mr. Tore,


Suggestion taken and I fixed the drawing...


Regards,
Don_
A man’s got to know his limitations…
Harry Callahan, SFPD

Online Don Prince

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Hello Mr. Tore,


I got some interesting photos of U-505... I am curious about the Dive Plane control stations; it looks like the two manual control wheels are tied together by a sprocket and chain.  Would that mean that if there was a power failure, then both dive planes would move in the same direction (sort of parallel to each other)? what do you thing?


Regards,
Don_
A man’s got to know his limitations…
Harry Callahan, SFPD

Offline tore

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Don.
It looks indeed as the two manual hydroplane controlwheels are interconnected by chaindrive, I never saw it before. I assume the electrical push button system is unaltered and thus the dual operated system is an emergency system. Generally the forward hydroplanes are used for depthcontrol (pitch) and the aft hydroplanes for leveling, on the VIICs. This system required two operators. todays submarines combines the two, thus reducing the manning.
I am astonish to see that the IXCs emergency system of the 1940 years already got a rude version of it. The flexibility of the two man operation is gone however, but I assume a possible porpoising effect as well, interesting.
Tore

Online Don Prince

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Hello Mr. Tore,
Hello Mr. Tore,

Does my update to the Fuel Oil Measuring (Sounding) look OK for the Type IX C U-Boat? I had a some problems figuring out Bild 1 and Bild 2....
 
Regards,
Don_
« Last Edit: 20 Aug , 2016, 00:00 by Don Prince »
A man’s got to know his limitations…
Harry Callahan, SFPD

Online Don Prince

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Hello Mr. Tore,


Can you translate this for me?


"Entwässern Entlütungsleitung bei Frostgefahr Tauchbunker 4 Stb bzw Bd"


Sheet 9 index item "f" I'm having a problem with "Frostgefahr"


Regards,
Don_
A man’s got to know his limitations…
Harry Callahan, SFPD

Offline tore

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Don.
Seems to me OK. Bild 1 shows the cock in a venting position. To be sure you are not fooled by an airpocket on top of the fuel you vent the top of the tank into the boat to check before you carry out the sounding. Bild 2 has a wrong translation Lenzen does not mean pressurizing but emptying eg. Bilgepump is Lenzepump. Thus you might connect a bilge hose to the system. Otherwise I guess your understanding of the system is OK.
Tore
« Last Edit: 20 Aug , 2016, 07:07 by tore »