Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Maciek.
We never used so many speed steps, we could use the 10 steps up. I wonder if 2HF and 2GF reflects on moving the telegraph twice indicating a certain step in increasing the revs as indicated on the board. For 3xAK this would mean you pull the handle back and forth 3 times and the diesel should run 480 revs instead of 470, but you could used the 10 revs up signal instead. As I say we did not use this kind of signals.
Tore

[tore]

Simon
As we have hardly any proper photo or drawing of the group exhaustvalve, I have tried to figure out by a modest sketch how the group exhaustvalve is constructed.
The housing is of course a full pressure proof steel casting containing the valve, however the operating gear for the shutting/ opening of the valve is placed outside as seen below. Sorry, the red segment should have been larger as the valve moves 90 degrees .The valve is shut having the waterpressure behind the valvedisc and the shaft for the shutting/opening is entering the pressure housing from fwd side whereas the grinding shaft is entering from the aft ( the square tip). A recess inside the housing allows for collecting drain and a drainpipe is connected to same.The housing is doublewalled being seawatercooled with crossover pipes passing flanges. I admit it is not easy to trace all the pipes I am still trying to figure out the details.
Tore

[tore]

Simon.
I am afraid we have to accommodate two more sets of rods for operating the mufflervalve, one for the shutting and one for the pneumatic grinderdrive. Having checked the limited drawings I have I would say the group exhausthousing is going through the pressure hull, which means no separate coolingpipe as far as I can see.I have tried to make a new rough sketch showing my idea of the muffler/ group exhaust valve arrangement, having omitted the coolingwater bridge pipes crossing the flanges. As you see the inside part of the group exhaustvalve and engine exhaustmanifold should be turned 90 degrees, sorry but I thougth this way of sketching wrongly shows more my ideas, so don`t get confused .
Tore

[tore]

Simon.
As to the driving gear for the two components I would assume the shutting/openingrods are placed at outboard side of the exhaustpipes and grinding gear rod inboard.
Note this is an assumption, as I have seen no drawings or pictures confirming this arrangement.  
Tore

[NZSnowman]

Tore, thanks for the new drawings! They are very useful and now I finally fully understand how the grinding works

I wondering if the "Brown" handal is the grinding handal for the muffler valve.
http://models.rokket.biz/index.php?topic=921.msg13393#msg13393

Also I was thinking there must be a third linkage as there still one Hull valve, sea water "Purple" that must drain the muffler somewhere

[NZSnowman]

Simon.
As to the driving gear for the two components I would assume the shutting/openingrods are placed at outboard side of the exhaustpipes and grinding gear rod inboard.
Note this is an assumption, as I have seen no drawings or pictures confirming this arrangement.  
Tore

Tore, here are the pressure hull openings.

I think:

• Shutting/openingrods are placed is inboard side (Orange).
• Grinding gear rod outboard (Brown).
• (Purple) is the Hull valve, sea water.

[tore]

Simon.
I do not think you have a handle for the grinding of the muffler valve as the rotation of the muffler valvedisc is done by the pneumatic motor operated by the LP airvalve in the engineroom, next to the airmotor. I cannot remember we had any drainvalve for the muffler, remember when surfacing the engines were started blowing the ballast tanks by exhaust, adjusting the backpressure by the mufflervalve, thus draining the muffler as well. We had always some water in the space between the mufflervalve and group exhastvalve but the water was generally collected in the drain chamber of the group exhaustvalve as shown on my sketch of same.
Tore

[NZSnowman]

Simon.
I do not think you have a handle for the grinding of the muffler valve as the rotation of the muffler valvedisc is done by the pneumatic motor operated by the LP airvalve in the engineroom, next to the airmotor. I cannot remember we had any drainvalve for the muffler, remember when surfacing the engines were started blowing the ballast tanks by exhaust, adjusting the backpressure by the mufflervalve, thus draining the muffler as well. We had always some water in the space between the mufflervalve and group exhastvalve but the water was generally collected in the drain chamber of the group exhaustvalve as shown on my sketch of same.
Tore

Yes, you are correct about the pneumatic motor.

So what is the "Brown" valve for? If you look hard you can see some marks next to the small arrow a "8" and "7" & "1".

[NZSnowman]

Tore, this is the "Purple" Hull valve, sea water. Do you think they have the wrong handle on this valve?

[tore]

Simon.
I guess you have found reference to the pressurehull openings some where, for the fitting of the rods they are a bit awkward but as the rivets of the engineroom cover is preventing a better place this was the compromise. I based my assumption on the photo below. The shaft for the pneumatic motor enters the pressurehull aft of the shutting opening valverod. It is almost touching the athwart rivets of the engineroom cover and fairly close to the top centerline.
Tore

[NZSnowman]

Simon.
As to the driving gear for the two components I would assume the shutting/openingrods are placed at outboard side of the exhaustpipes and grinding gear rod inboard.
Note this is an assumption, as I have seen no drawings or pictures confirming this arrangement.  
Tore

Tore, here are the pressure hull openings.

I think:

• Shutting/openingrods are placed is inboard side (Orange).
• Grinding gear rod outboard (Brown).
• (Purple) is the Hull valve, sea water.

I was just about the say the same thing, but you must be a faster typer than me 

Tore you are correct, shutting/openingrods is placed at outboard side of the exhaustpipes  (Orange) and grinding gear rod inboard (Red).

[tore]

Simon.
The brown handle is a puzzle to me. I think I remember vaguely we had some grease distribution boxes outside the pressurehull, it could be a selector handle for the greasing point with the numbers referring to the points but this would require a bit research before adding it to your drawing. The other  valve looks like an important sea valve but right now I have no suggestion, hopefully something pops up.
Tore

[NZSnowman]

Simon.
The brown handle is a puzzle to me. I think I remember vaguely we had some grease distribution boxes outside the pressurehull, it could be a selector handle for the greasing point with the numbers referring to the points but this would require a bit research before adding it to your drawing. The other  valve looks like an important sea valve but right now I have no suggestion, hopefully something pops up.
Tore

I love your idea about grease distribution boxes, as it solution my other problem I was having with the number of openings

On page 30 of the Type VIIC Manual

[NZSnowman]

Simon.
I do not think you have a handle for the grinding of the muffler valve as the rotation of the muffler valvedisc is done by the pneumatic motor operated by the LP airvalve in the engineroom, next to the airmotor. I cannot remember we had any drainvalve for the muffler, remember when surfacing the engines were started blowing the ballast tanks by exhaust, adjusting the backpressure by the mufflervalve, thus draining the muffler as well. We had always some water in the space between the mufflervalve and group exhastvalve but the water was generally collected in the drain chamber of the group exhaustvalve as shown on my sketch of same.
Tore

Yes, you are correct about the pneumatic motor.

So what is the "Brown" valve for? If you look hard you can see some marks next to the small arrow a "8" and "7" & "1".

Tore, I imagine the small pipe on the right of the valve would be the grease input line?

[tore]

Simon.
Yes, if you look at the aft engine bulkhead starboard side, just underneath the drainvalves from the starboard group exhaust valve you will find a round container having a pumphandle, see aft sideview yard drawing. This is the greasepress pump, it is a shot in the dark, but worth while checking.
Tore