Tores mailbox VIIC and VIIC/41 operation and technical details

[NZSnowman]

Simon.
On the British report of U 570. You can read an accurate description of the exhaust valvegrinding. The muffler valves are turned by the pneumatic motors, the group exhaustvalves are handoperated and the same is the Junker compressor exhaustvalve.

Tore

Thanks Tore, I had a look.

Tore & Maciek, has anyone see any drawings of the exhaust valve?

[tore]

Simon
I guess you might find some details in your  own photos as this one below. I`ll check for more tomorrow.
Tore

[NZSnowman]

Simon
I guess you might find some details in your  own photos as this one below. I`ll check for more tomorrow.
Tore

I will for sure have more questions for you tomorrow In the VIIC manual it said there are four openings for the Grinding mechanism for the exhaust gas valves stb. and port. I have found 2, now looking for the other two.

[NZSnowman]

Tore & Maciek, can you guys please double check my valves.



Blue = Exhaust gas flap valve, inboard. Valve 'P'. http://www.uboatarchive.net/U-570Plate13.htm
Green = Pneumatic grinder
Purple = Drain valve

[tore]

Simon
Exhaust valves
Below is the normal systemsketch indicating the relevant components. The first valve is the group exhaustvalve which is situated in the peculiar cast steelcasing inside the pressurehull. It is a hinged valve which is "folded down " like a flap. You find a very good photo on u historias exhaustgas page. On this picture you see a square shaft stud marked 4 next to the hinge. On this shaft you put a lever for turning the groupvalve disc. When this valve is shut eg. the valveseats are in contact, you are moving the  handle, turning the valvedisc and thus grinding the valve.
Tore

[NZSnowman]

Simon
Exhaust valves
Below is the normal systemsketch indicating the relevant components. The first valve is the group exhaustvalve which is situated in the peculiar cast steelcasing inside the pressurehull. It is a hinged valve which is "folded down " like a flap. You find a very good photo on u historias exhaustgas page. On this picture you see a square shaft stud marked 4 next to the hinge. On this shaft you put a lever for turning the groupvalve disc. When this valve is shut eg. the valveseats are in contact, you are moving the  handle, turning the valvedisc and thus grinding the valve.
Tore

Tore, I still a little confuse

So on the picture at u historias, No. 4 operate the grinder & No. 2 operate the hinged valve?

[tore]

Simon.
The exhaust valve are operated by two devices, the shutting and the grinding. The valve is hinged and the hingeshaft is operated by a wheel and by linkage turning the shaft and moving the valvedisc to an open/shut position. The circumference of the valvedisc has a bevelled gearrim which meshes a short worm fixed to another shaft inside the hingeshaft. This shaft can be turned either by hand ( group exhaustvalve) or pneumatic motor( muffler exhaustvalve). The worm is always in contact with the rim meaning you can rotate the disc in any position. Unfortunately I don`t have any drawing but have tried to indicate the system on the muffler valve below.

[tore]

Simon
Exhaust valves
Below is the normal systemsketch indicating the relevant components. The first valve is the group exhaustvalve which is situated in the peculiar cast steelcasing inside the pressurehull. It is a hinged valve which is "folded down " like a flap. You find a very good photo on u historias exhaustgas page. On this picture you see a square shaft stud marked 4 next to the hinge. On this shaft you put a lever for turning the groupvalve disc. When this valve is shut eg. the valveseats are in contact, you are moving the  handle, turning the valvedisc and thus grinding the valve.
Tore

Tore, I still a little confuse

So on the picture at u historias, No. 4 operate the grinder & No. 2 operate the hinged valve?

Simon.
I think so.
Tore

[tore]

Simon
Group exhaustvalves
The name sound perhaps a bit strange to you but is a very common Royal Navy term in the submarine service, meaning a device collecting several connections, like exhaust outlets from 6 cylinders (manifold). Down below is a photo showing the  valvewheels in the engine room for the 3 pairs of relevant exhaust valves.
The arrangement deviates a bit from British and US subs as it is adopted for using exhaust pressure for blowing the ballasttanks in semisurfaced position instead of a lowpressure electric blower as the case of other submarines. The muffler valves were used in a semi open position when blowing the tanks in order to adjust the exhaust backpressure. One disadvantage of the system was that the muffler ( dry muffler) exhaustvalve had a tendency to get carbonizes and deposits could be formed both on the valveseating as well as the gear rim and wormwheel, thus blocking the device. As this was mostly common on the mufflervalve a pneumatic motor was fitted  and the valve had to be rotated may be once a watch whereas the group exhaustvalve had a hand turning with handles and ratchets.
As you see the wheels have a bore where you could put a bar giving an extra force to the shutting moment, moreover the group exhaustvalves had a pointer for shut and open 90 degrees.

Tore

[tore]

Simon
As an addition to my last post I should perhaps mention that the engineer having divingposition in the engineroom had a remarkable technique  grinding the mufflervalves  when diving. In order to get a proper pressure on the valve disc he started the grinder some 2-4 meter submerged and got a excellent pressure.  At periscope depth however the pressure was too high and the pneumatic motor stalled. In spite of grinding we had occasional leakages but a proper drain took normally care of that. Once or twice we had to surface due to excessive leakage and a couple of times we flooded the engine via the exhaustpipe. As a rule we never started the engines without turning with open indicatorcocks and more than once water squirted out of the cocks. A disadvantage with using the pneumatic grinder was building up pressure inside the boat, at excessive grinding this could happen.

Tore

[NZSnowman]

All the drain lines seen on Plate 13 http://www.uboatarchive.net/U-570Plate13.htm are within the pressure hull.

So, what is the 'Hull Valve Sea Water' marked as purple used for?

[NZSnowman]

Tore, I try to track the drain piping around the Exhaust manifold but I was not able to Too many pipes in a small area, not enough photo

[tore]

Simon.
 I am not sure I understand your question. U-570 plate 13 is not easy to understand as you have sea coolingwater pipebends, anti corrosionpipes and exhaust drain connection  drawn in the same way. The main drain having connection to the sea is the valve m on plate 16 or o on plate13. This valve has to be open in case of leaking muffler valve.
Tore

[tore]

Simon.
As to my last post I should probably say...or o marked as hullvalve on plate 13.
Tore

[SnakeDoc]

Hi Tore,


I wonder about one thing: on the following image and in the document (http://uboatarchive.net/Manual.htm page 14, table Test data) are gathered engine/motors orders and corresponding RPMs and speed. I suppose, that given speeds  corresponds the orders given to both engines/motors.





 The orders: Kleine Fahrt,  Langsame Fahrt, Halbe Fahrt, Gro

[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

[NZSnowman]

Tore, any idea what the grease distribution boxes would look like? Or how it may work?

[NZSnowman]

Tore, I have added the two new linkages, and updated the muffler


Fig. 1. New drawing


Fig. 2. Old drawing.

[tore]

Simon
Greasepump.
On starboard side aft engineroom bulkhead you see the greasepump as on the photo below. Marked on this picture you probably see the distribution cock, the namedisc and behind a steelblock which I assume is the distributionbox which I guess is outside the pressurehull  in the case of the handle you questioned. Again this is an assumption from my side.  
Tore

[tore]

Simon
Greasepump.
I guess the greasepump has not changed very much since the time of the VIICs. Below is a drawing of a to days execution, you shall find pneumatic driven  versions on the gas stations I believe. In the case of the VIICs it was operated by a handbar more or less as shown on the drawing below.
Tore

[tore]

Simon.
Grease pump.
I was too quick marking the greasepump in my post above mixing up the drain cock with a grease cock . I got hold of a better picture of the pump as shown below, may be with your material you should be able to follow the greaselines to the cock?   On this photo you a able to have another view of the group exhaustpipe valve draining as well.
Tore

[NZSnowman]

Hi Tore

I tried to track the grease line from the pump but could follow it fully as it went behind a larger pipe.

I did noted that there are two small pipes from the pump, I think sometime after 1943 they added a 2nd grease line to the pump. I follow both lines forward  to the pressure hull. One grease line goes  to the distribution box and the newer 2nd lines goes somewhere new. Below you can see the grease line and small tap.


Fig. 1. The 2nd newer grease line.

[NZSnowman]

Tore, I have added the two new linkages, and updated the muffler


Fig. 1. New drawing


Fig. 2. Old drawing.

Top view

[tore]

Simon.
I have been looking into the grease distributor theory the whole day, and I can not see any other device which fit into this handle. My theory is as follows one of the pipes end up at the shutoff cock before entering the grease distribution system. The system has to be straight forward and simple. On my sketch below I am showing my idea.The handle spindle is bored allowing grease under pressure to enter a space made by a lantern space ring on both side of the packing,(purple) thus entering the hollow spindle through the pressurehull and into a rectangular distribution box on the outside of the pressure hull. In the distribution box is a circular disc having bore in connection with the hollow shaft. The disc circumference have shallow bores, except the bore to the shaft, corresponding to the outlets of the distributionbox and the bores contains a springloaded ball acting as a shutoffvalve for the outgoing pipes at the same time providing notches of the disc movement. The idea is to have full control of the supply to the selected greasepoint and that no leakages is entering any other pipes except the selected, thereby ensuring the selected greasepoint is lubricated.
This ended as a long story, may be the sketch is easier to understand.
Tore

[NZSnowman]

Simon.
I have been looking into the grease distributor theory the whole day, and I can not see any other device which fit into this handle. My theory is as follows one of the pipes end up at the shutoff cock before entering the grease distribution system. the system has to be straight forward and simple. On my sketch below I am showing.Thehandle spindle is bored allowing grease under pressure to enter a space made by a lantern space ring on both side of the packing,(purple) thus entering the hollow spindle through the pressurehull and into a rectangular distribution box on the outside. In the distribution box is a circular disc having bore in connection with the hollow shaft. The disc having shallow bores, except the bore to the shaft, corresponding to the outlets of the distributionbox and the bores contains a springloaded ball acting as a shutoffvalve for the outgoing pipes at the same time providing notches of the disc movement. The idea is to have full control of the supply to the selected greasepoint and that no leakages is entering any other pipes except the selected, thereby ensuring the selected greasepoint is lubricated.
this ended as a long story, may be the sketch is easier to understand.
Tore

Tore, this is great!!! The sketch is fantastic

I have a similar idea in my head but your sketch is far better!

[NZSnowman]

Grease Distributor and Lines

[tore]

Simon.
Excellent, for some reason I have a picture in my head that the distribution boxes were rectangular, but circular is of course easier, so leave it at that.
Tore

[NZSnowman]

Simon.
Excellent, for some reason I have a picture in my head that the distribution boxes were rectangular, but circular is of course easier, so leave it at that.
Tore

Tore, I went with a octagon

[tore]

Simon.
Just as good, I based my assumption on the cheapest way of production.
Tore

[tore]

Simon.
The only item left on the valve question is the purple valve. There are two valves each symmetrically placed on port and starboard side. Both have a handle of the boardvalve seawatertype so I guess that`s correct. This rules out the  single drain of the supplyline to the seacompensating head tank in the conningtower. The valves are not shown on any systemdrawings available to me, thus systems before the schnorkel. My assumption would be this is a seawatervalve installed on the schnorkel boats. The schnorkel air inlet and exhaust outlet would not require two symmetrical placed seawater valves in this position. When schnorkeling the dieselengine  sea coolingwater has not been changed  and leaves overboard in the normal way, trapped air in the outboard seacooling watersystem  could cause problems. On the old systemsketches it is an outboard ventcock in the coolingwater space for both silencers marked "n" on plate 13 and pointing forward, this cock is not accessable during schnorkeling. May be the purple valve is a modification for the schnorkeling boats enabling venting while schnorkeling? Again this is only an assumption from me.
Tore

[NZSnowman]

Tore, I have added the rare Style 6, Late war Diesel exhaust outlets¹. There are no known drawings/plans and only five known photo's of this style. With this style the outlets are below the waterline. There is very little room between the pressure hull and casting (about 190 mm) so you can not run the exhaust pipe directly to the outlet. So I have added a box around the outlet to get the necessary volume. I also had to run the exhaust pipe between the pressure hull/casting/and high pressure bottles.
 
Tore, welcome any feedback on my engineering.

1. The Wolf Pack: A Collection Of U-Boat Modelling Articles by Dougie Martindale / Wink Gris

[NZSnowman]

Simon.
The only item left on the valve question is the purple valve. There are two valves each symmetrically placed on port and starboard side. Both have a handle of the boardvalve seawatertype so I guess that`s correct. This rules out the  single drain of the supplyline to the seacompensating head tank in the conningtower. The valves are not shown on any systemdrawings available to me, thus systems before the schnorkel. My assumption would be this is a seawatervalve installed on the schnorkel boats. The schnorkel air inlet and exhaust outlet would not require two symmetrical placed seawater valves in this position. When schnorkeling the dieselengine  sea coolingwater has not been changed  and leaves overboard in the normal way, trapped air in the outboard seacooling watersystem  could cause problems. On the old systemsketches it is an outboard ventcock in the coolingwater space for both silencers marked "n" on plate 13 and pointing forward, this cock is not accessable during schnorkeling. May be the purple valve is a modification for the schnorkeling boats enabling venting while schnorkeling? Again this is only an assumption from me.
Tore

Tore, I am not sure also

I checked the few drawings I have of the schnorkel system, and I can not see any pipes that look like drains

I off to work tomorrow so I will check my other drawings in a few days.

Maciek, do you what these valves are for?

[tore]

Simon
I guess the box you designed has a duct going down below sealevel to the outlet thus act like the sparkarrestor which is the last item before the exhaust goes overboard, otherwise the outlet outside the casing looks very much like the U 995 design having outlet above the sealevel as shown on the drawing below.
Tore

[NZSnowman]

Simon
I guess the box you designed has a duct going down below sealevel to the outlet thus act like the sparkarrestor which is the last item before the exhaust goes overboard, otherwise the outlet outside the casing looks very much like the U 995 design having outlet above the sealevel as shown on the drawing below.
Tore

Tore, would you need a spark arrestor if the exhaust outlets are always underwater?

Here the side view. You can see the box that is between the casting and the pressure hull, and the exhaust pipe running around the high pressure bottle and down to the box. 

[tore]

Simon.
I guess not if the outlet is submerged all the time. I would assume however that there would be a kind of sparkarrestor in the box indicated by you.
Below a photo showing the exhaustoutlet of the KNM Kaura at the handing over to the Germans as U 995 Oct 2. 1971.
Tore

[tore]

Simon.
I have to confess I didn`t like my yesterdays assumption of the purple valve very much. Having another look at the outboard coolingwater system it struck me the pipes as drawn on plate 13 allows full direct seaconnection to the system all the time. I do not remember the system of course, but no way you allow full seawater pressure to the inside of a submarine without a shut of valve (depthcharging- deepdiving etc.) My revised theory would be, the purple valve marked correctly as a board seawater valve  equipped as an important valve with a grease cup and a shut/open indicator could be the sea coolingwater shut off valve. The most likely place to install such a valve would be in the coolingwater bend crossing the flange of the group exhaustvalve to the mufflervalve housing. This is pretty close to the drawn purple valve. Below is my sketch showing the assumed valve. Repeating my shelf, this is an assumption. The drawback of the theory is  that the germans have omitted this essential valve on all the systemsketches, that is hardly to believe. Open for any other ideas but the system has to be capable of being shut of from the sea.
Tore

[TopherVIIC]

Hmm... I agree with Tore in that there would not be a direct sea connection without a shutoff valve... too risky. Is it a question of faulty recording? Is it a change put in after the manuals were produced? or, perhaps a post war change? Perhaps the owners of poor U-995 thought it a useful thing to try, but one not on the orig German manuals? Was the change tried as the war was winding down and people thought it not worth recording at that point? These observations bring up so many exciting questions, don't they! B-)
Christopher... hanging on the edge with curiosity...

[tore]

When the map doesn`t match with the terrain it is usually  an advantage to follow the terrain. In this case we have definitely two objects being genuine seaboardvalves having a construction of  important valves, I cannot imaging any other purpose for these valve at that place. On the other hand the German "grundlichgkeit" makes it difficult to understand why these important valves are not shown on any drawings showing the MAN or GW systems way back in time, after all this is not a late war thing, but basic submarine design. It puzzles me, may be I have overlooked something, am I getting too old? .
Tore

[TopherVIIC]

When the map doesn`t match with the terrain it is usually  an advantage to follow the terrain. In this case we have definitely two objects being genuine seaboardvalves having a construction of  important valves, I cannot imaging any other purpose for these valve at that place. On the other hand the German "grundlichgkeit" makes it difficult to understand why these important valves are not shown on any drawings showing the MAN or GW systems way back in time, after all this is not a late war thing, but basic submarine design. It puzzles me, may be I have overlooked something, am I getting too old? .
Tore

Perhaps there is a drawing map to lead us back to the path... but there are those of us who enjoy thinking beyond a drawn black and white image.

[tore]

True Christopher, hopefully we find the path. So I keep looking and pondering hoping to find the correct input  for the magnificent artwork Simon as well as you makes.
Usually we end up pretty close to the real thing, at the  same time it is fun though.
Tore

[NZSnowman]

Simon.
I guess not if the outlet is submerged all the time. I would assume however that there would be a kind of sparkarrestor in the box indicated by you.
Below a photo showing the exhaustoutlet of the KNM Kaura at the handing over to the Germans as U 995 Oct 2. 1971.
Tore

Tore, I was thinking how hot would the exhaust gases be when it reached the outlet?
 
Would it be a bad thing to have hot exhaust gases hearting up the pressure hull, in a small area?

Tore, not sure if you seen Style 6 of the exhaust outlets before, so here a few photo's and drawings.

[tore]

Simon.
As far as I can see the style 6 exhaust outlet is submerged in the area where you have a possible contact with the pressure hull, moreover the exhaustgases are considerably cooled  at the outlet. I don`t believe you would have a problem.
Tore

[NZSnowman]

Simon.
I have to confess I didn`t like my yesterdays assumption of the purple valve very much. Having another look at the outboard coolingwater system it struck me the pipes as drawn on plate 13 allows full direct seaconnection to the system all the time. I do not remember the system of course, but no way you allow full seawater pressure to the inside of a submarine without a shut of valve (depthcharging- deepdiving etc.) My revised theory would be, the purple valve marked correctly as a board seawater valve  equipped as an important valve with a grease cup and a shut/open indicator could be the sea coolingwater shut off valve. The most likely place to install such a valve would be in the coolingwater bend crossing the flange of the group exhaustvalve to the mufflervalve housing. This is pretty close to the drawn purple valve. Below is my sketch showing the assumed valve. Repeating my shelf, this is an assumption. The drawback of the theory is  that the germans have omitted this essential valve on all the systemsketches, that is hardly to believe. Open for any other ideas but the system has to be capable of being shut of from the sea.
Tore

I have not seen a valve with this style of open/shut indicator before on the Type VIIC, perhaps it could be evidence that it was not added by the Germans or very very late into the war (in Norway)

[tore]

Simon.
I believe it is a original German valve, if you look I guess you shall find more valves with an indicator, not always identical to this one, some have a threaded ring with a tap in a  pedestal slot travelling on a threaded part of the valve spindle, others have a double pointer fixed to the valve spindle, the latter you can  find as a hull fuelvalve just above the IMO motor for the fwd periscope hoist on the port side of the fwd controlroom.
The main problem is that on the systemsketches we have seen you have full seapressure directly to the seawater coolingsystem without a shut off valve for diving.
Tore

[tore]

Simon.
The mysterious purple valve.
Finally I believe we have found an explanation which hold water . The fuel/ballast tanks no 2 port and starboard have a residual venting. The venting of the fuel/ballast tanks are usually operated from the controlroom. In the fuel mode the ballasttanks 2 and 4 port and starboard are separated by gatevalves operated from deck. However the venting ducts have an emergency shut valve Right at the merger of the ventduct and the saddletank. The philosophy is that in case of damage to the ventingducts you should shut the the emergency vent valves to save the buoyancy of the saddletanks. The same philosophy must be valid for the residue venting as well, but I have found no mentioning in the literature of these emergency valves in the aft part of fuel/ ballast tanks 2 port and starboard. My conclusion is nevertheless: the purple elaborate and important valves are the emergency shut off valves for the residual venting duct of the fuel/ballasttanks 2 port and starboard. As a proof I show a picture of the emergency shut of valves for ballast/fuel tanks 4 port and starboard operated from the controlroom, as you see they are identical only the handle is removed.
Tore

[NZSnowman]

Fig. 1. Pressure hull openings.


Fig. 2. New exhaust system.

[tore]

Simon.
You have probably seen it, but anyhow below is the drawing of the emergency ventvalve fitted directly on the ballast saddletank. The intricate coolingpipe arrangement for the group exhaust valves follows this evening my time, I believe the explanation and solution of the cooling water shut of valve has been found just minor details remains.
Tore.

[SnakeDoc]

Hi Tore,

The fuel/ballast tanks no 2 port and starboard have a residual venting. The venting of the fuel/ballast tanks are usually operated from the controlroom. In the fuel mode the ballasttanks 2 and 4 port and starboard are separated by gatevalves operated from deck. However the venting ducts have an emergency shut valve Right at the merger of the ventduct and the saddletank. The philosophy is that in case of damage to the ventingducts you should shut the the emergency vent valves to save the buoyancy of the saddletanks. The same philosophy must be valid for the residue venting as well, but I have found no mentioning in the literature of these emergency valves in the aft part of fuel/ ballast tanks 2 port and starboard. My conclusion is nevertheless: the purple elaborate and important valves are the emergency shut off valves for the residual venting duct of the fuel/ballasttanks 2 port and starboard. As a proof I show a picture of the emergency shut of valves for ballast/fuel tanks 4 port and starboard operated from the controlroom, as you see they are identical only the handle is removed.

I like your explanation very much. Here is another photo of the emergency vent of the Tauchbunker 4:



What wonders me, is that on the "vent diagram" (http://uboatarchive.net/U-570Plate16.htm) the residual air vent duct has no emergency vents. Also, in the description of the Tauchanlagethere is said:

An den Austritten der Entl

[tore]

Maciek.
I agree with you, the gate valve is probably fairly close to the ballasttank anyhow. As you have evidence in the original Tauchanlage text I believe we now finally have come to the final correct arrangement.
Tore

[tore]

Simon.
The last and may be most complex item on this topic is probably the group exhaust coolingwater piping. The system sketches gives the impression that the internal coolingwater system is subjected to full seawaterpressure which is an impossibility. Based upon limited available sketches and photos I have have made the following proposal: It is a shut of seavalve fitted on the group exhaust valve housing at the side of the double walled drainspace. On the u historia photo of the group exhaust valve,  it is the biggest valve having pipeconnection marked 6. The double walled cast steel group exhaust valvehousing  can for sure  take the max seawaterpressure. All the other items in the internal coolingwater system you want to have behind this shut off valve. The more flanges packings and stuffingboxes which are subjected to exessive pressure the more risk you have for serious or even fatal leakages. The  valve housing consist of 3 parts, the main housing, the endcover and an exhaust manifold transmissionflange. The latter two have to be cooled as well and as they should be behind the main seavalve, it would require some unusual pipings. On the sketch below you see my proposal, the only pipe I have not been able to get confirmed is the top pipebend for the coolingwater from the exhaust manifold to the transmission flange.
As so many times before the real execution deviates a bit from the systems sketches, they just show the principle, not the execution. I have to finish off with my reservation: this is a proposal.
Tore

[NZSnowman]

Simon.
The last and may be most complex item on this topic is probably the group exhaust coolingwater piping. The system sketches gives the impression that the internal coolingwater system is subjected to full seawaterpressure which is an impossibility. Based upon limited available sketches and photos I have have made the following proposal: It is a shut of seavalve fitted on the group exhaust valve housing at the side of the double walled drainspace. On the u historia photo of the group exhaust valve,  it is the biggest valve having pipeconnection marked 6. The double walled cast steel group exhaust valvehousing  can for sure  take the max seawaterpressure. All the other items in the internal coolingwater system you want to have behind this shut off valve. The more flanges packings and stuffingboxes which are subjected to exessive pressure the more risk you have for serious or even fatal leakages. The  valve housing consist of 3 parts, the main housing, the endcover and an exhaust manifold transmissionflange. The latter two have to be cooled as well and as they should be behind the main seavalve, it would require some unusual pipings. On the sketch below you see my proposal, the only pipe I have not been able to get confirmed is the top pipebend for the coolingwater from the exhaust manifold to the transmission flange.
As so many times before the real execution deviates a bit from the systems sketches, they just show the principle, not the execution. I have to finish off with my reservation: this is a proposal.
Tore

Q. Tore, From your group exhaust coolingpipes a.jpg drawing you have drain line (Red) inboard and the crossover line (Orange) outboard (Top Drawing). This were a reason why have done it this way? As I would had imagine it was the other way, with the crossover line inboard and the drain outboard, as would used the minimum amount of pipe (Bottom Drawing).


Fig. 1. Cross-section with pipe layout.

[NZSnowman]

'T' handles hatches within the floor plating

Tore, look what I found today, you can see the handle


U-166 (http://www.mille-sabords.com/forum/index.php?showtopic=40300&st=175)

[NZSnowman]

Tore, slowly checking and updating the piping (colours piping).

[tore]

Simon
Coolingwater group exhaust valve drain.
If you look right down at the side of the E-room door I believe you find a drain collecting funnel for the drainpipes that`s why I put the drain inboards.
Tore

[tore]

Simaon.
T handles.
Very good, you realize of course the engines are not GWs.
Tore

[tore]

Simon.
Group exhaustvalve housing.
Very good you made a drawing of this item. If you check the u historia photo I believe you shall see the transferflange from the exhaustmanifold, having a smaller diameter than the inlet to the housing. A transfer piece consisting of two flanges having different diameter and a cooling waterspace in between is causing the complication. I have taken the liberty to mess up your nice drawing in order to explain what I mean. see the drawings below.
Tore

[tore]

Simon.
Group exhaustvalves.
Having received further pictures I have to revise my last theory slightly. The revised system drawing is shown below. I guess there is a small detail which may be a bit unclear, I don`t believe there is a connection at the crossing point, engine coolingwater pipe and the pipe to the drain- crossover selector cock. In fact on the photo the pipe is not shown, I am sure it is there but as a separate pipe going somewhere else. Otherwise I hope the sketch is self explaining.
I have again messed up your nice drawing in an attempt to show the complete arrangement. Most of the changes are based on photos and drawings. Otherwise the system is following basic requirements like keeping pipes, flanges, packing and stuffingboxes which are not pressureproof behind the main overboard seavalve. Further the coolingwater should go from low inlet to high outlet. The main coolingwater outlet from the engine is shown being a fairly large pipe, the full amount of coolingwater can not flow through the narrow coolingspaces of the transmission flange and end cover. They are cooled in series and the pipes are much smaller as shown, howewer the only connection not confirmed by documents is  the small pipe branch off from the main cooling waterpipe ( or exhaustmanifold) to the transmission flange. I have indicated two possibilities on the drawing. The system is elaborate and many pipes are stacked on top and behind each other, this is not easy to draw. The collection of valve and pipeoutlets, drains and vents is really cramped in the aft bulkheadarea  and would require another study I guess.
Tore

[OldNoob]

I am just blown away by the technical knowledge of the contributers on this forum.
I bet with everyones combined knowledge here we could actually build a real U-boat!
All we would need is a wealthy, slightly off,  financier like the gentleman building Titanic II, and lots of young muscle

Seriously though, just amazed by the information and knowledge contributed on this forum.

[TopherVIIC]

I am just blown away by the technical knowledge of the contributers on this forum.
I bet with everyones combined knowledge here we could actually build a real U-boat!
All we would need is a wealthy, slightly off,  financier like the gentleman building Titanic II, and lots of young muscle

Seriously though, just amazed by the information and knowledge contributed on this forum.

OldNoob,
I am not only blown away by the assembled  tech knowledge, but by the forensic  extrapolation we have been able to do with a truly limited set of input. There are only so many plans, so many period photos, only so many boats, and 1 Pajama-wearing Tore!

[tore]

Hi guys.
I have been through this before, graduating 60 years back as lieutenant (E) on Royal Navy's engineering training course on A,F, S and U classes of submarines in UK, coming home realizing I got a VIIC 41 totally different, with no contact with the germans and practically no drawings. One advantage to present days though, you was on board and could crawl,follow pipes and look at the items. Howewer the testing that your assumptions was right or wrong was slightly more exciting than experiencing the evaluation of my present days assumptions on this thread today.
Tore

[NZSnowman]

Tore, here the remaining of the engine exhaust, how does it look?

[tore]

Simon.
Looks fine. May be it is time to put in some spice in in the spaghetti. You love for details require venting of the exhaust manifold cooling bends,foldable handle for the starting air handwheel and the manometer for the supercharger pressure. Sorry for my bungling on your nice drawing.

Tore

[tore]

Off the topic.
Surfacing.
I have mentioned before the normal way of surfacing, nicely take the boat up by hydroplanes to periscope depth, the quick sweep with the periscope before blowing all the ballasttanks until semisurfaced in a horizontal position and then blowing the tanks by diesel engine exhaust or in case of RN U class submarine by electric blower.
It happens howewer you have to make emergency surfacing, blowing you ballasttanks at great depth with an incredible amount of HP air. Then you accelerate towards the surface and in case of using the hydroplanes and E-motors as well you might end up braking the surface like the picture below, which I found in one of my Norwegian submarine pamphlets. The picture is presumably taken of a Norwegian U class surfacing in a Norwegian fjord. I guess more for show off rather than necessity. I guess the surfacing angle would be close to 45 degrees exceeding the spilloff limit for the battery acid , spectacular but not to be recommended.
Tore

[NZSnowman]

Tore, a few more pipes...

[tore]

Simon.
I am back with a few remarks tomorrow as I am checking a few pipedetails which seems to take more time than I anticipated. It is primarily the connection to the transmissionflange cooling which needs some attention.
Tore

[NZSnowman]

No worrys, I am off to the big city today to do some shopping, so no u-boat drawing today.

[NZSnowman]

Tore, one thing, how did the cooling water get outside the pressure hull through the hull flange?

If you were looking into the flange at the top, would you see the inner collar for the cooling water, if so how wide is it?

[tore]

Simon
The group exhausthousing don`t have a flange going through the coolingspace, it is simply a ringflange intergrated with the outer surface of the housing without obstructing the cooling waterflow out of the pressurehull. You want see the coolingwater space at all it is entirely closed like a cooling waterspace for a cast iron car engineblock.

Tore

[tore]

Simon
I guess you see the transmissionring small flange at the exhaust manifold side on the shipyard drawing top view and the groupexhaust housing on the sideview the difference between the two migth give you an estimate for the coolingwater dimension.
Tore

[NZSnowman]

Something like this?

[tore]

Simon
Yes.
Tore

[tore]

Simon.
It got to be only one flange in contact with the pressure hull and it looks like the flange is fixed from the inside, the housing is then free to (heat) expand outwards.

Tore

[tore]

Simon.
Group exhaust valve coolingwater pipes.
To make an understandable drawing of this system is not easy, so when keeping an eye on the confusing drawing below I`ll try to give an explanation:
making use of the systemdrawing and copy the system would not work so basis for the described system is photos and common engineering sense.
The main coolingwater outlet from the dieselengine is close to where the manifold endflange joins the transition piece flange. The pipe goes down to the main coolingwater valve at the aft bulkhead, to the short pipe between the main cooling watervalve and the main seavalve and then via the main seavalve to the group exhaust valve and  overboard.
Immediately after the exhaust manifold it is a small pipe branch off which take some of the coolingwater to the lower part of the transition flange, the water leaves the same flange at the outlet on the top. Then the water goes to the lower inlet of the endflange and leaves same at the outlet on the top. It goes down and join the short pipe between the main coolingwater valve and the main sea ( overboard) valve. On the short pipe between the two mainvalves is a branch off to a two way cock, this cock can be put in drain position leading  the system to a funnel and bilge or to the other position connecting the system the the other engine system.
The main drain pipe (yellow)and valve is obvious and ends together with other drains in a funnel to the bilge.
Allthough not shown on one of the engines, there should be a manometer connection to the main drain of the group exhaust valve, that drain comes from the space between the group exhaustvalve and mufflervalve which might have a severe leakage and full seapressure in the space.
The system is based on interpretation of photos and some basic musts but in the end an assumption from me.
Tore

[NZSnowman]

Tore, a few more pipes and tweaking of alignments

[tore]

Simon.
It is beginning to look like the real thing.
I am a bit in doubt of the location of the valve and pipe assembly at the aft bulkhead. I know you recently relocated the supercharger. With a less professional way I used that as a reference. On the shipyard drawing topview it looks like the centerline of the main coolingwater outlet matches the centerline of the outboard supercharger shaft. On your drawing the centerline of the pipe is a bit offset to the inboard. I again bungled with you drawing and put the coolingwater outlet as on the shipyard drawing see drawing below. With reference to the photos I placed the main cooling water pipe  straight down to the main coolingwater valve realizing it created some distance to the  valve inboard.
Tore

[tore]

Simon.
The coolingwater branch off.
My assumption is founded on the photo below and the orthodox way of cooling waterflow, in at the lowest point out at the highest
Tore

[tore]

Simon.
Further to my previous post I show below my basis for the assumption of the pipearrangement for the transition piece and main drain.
Tore

[NZSnowman]

Tore, a few more pipes and tweaking of alignments

[tore]

Simon.
Slowly but steady approaching the complete arrangement.   I noticed the  frames at the group exhaustvalve hull outlet have a larger distance to accommodate a large flange and that the hullpassage is a bit different from what assumed. I shall try to figure out further details. Below I have tried to indicate the coolingwater pipes.
Tore

[NZSnowman]

Simon.
Slowly but steady approaching the complete arrangement.   I noticed the  frames at the group exhaustvalve hull outlet have a larger distance to accommodate a large flange and that the hullpassage is a bit different from what assumed. I shall try to figure out further details. Below I have tried to indicate the coolingwater pipes.
Tore

Tore, I can not understand the two new pipes you have added to my drawing

Are you jointing the new Main cooling water outlet exhaust manifold  pipe to a exiting pipe (Red; This pipe is between the transfer flange and manifold)?

[NZSnowman]

A small update today.

[tore]

Simon.
I am the first to admit it is not easy to sort out these pipes.   I have made a drawing trying to explain my assumption below. The drawing shows the port engine in order to make it easier to check with the u historia photo.
I guess it is bit easier when you add the larger flange of the transition piece towards the group exhaustvalve housing ( red dotted oval). The largest red circles indicate the pressurehull flange for the hull outlet on top of the group exhaustvalve.
From the exhaust manifold main cooling waterbend out  you have a branch off (1) purple pipe going to the inlet at the bottom of the transition piece( 2). Out of the transition piece at the top (3.) From (3 )green pipe goes to the bottom of the endpiece( 4) and out at the top (5). The pipe now light blue goes down to the pipe between the main coolingwater valve and the main overboard valve.
Tore

[tore]

Simon.
Further to my above post. To have a better understanding, remember the basic for coolingwater flow : inlet at the bottom and outlet at the top. On the photo below I have indicated the branch off from main coolingwater pipebend to inlet transition piece ( purple pipe).
Tore

[NZSnowman]

Tore, thanks for the photo & drawings.

How does this look?

[tore]

Simon.
This make sense to me!   How about adding the other flange of the transitionpiece?
Tore

[tore]

Simon.
Transition piece.
Just indicating the two flanges of the transition piece which I guess is necessary to locate the coolingwater outlet.
Tore

[NZSnowman]

I feel that because of the shape of the group exhaust valve casting you would see the other flange. From the photo, you can see that the nuts are under and inward of the casting.

[tore]

Simon.
I see. You know for sure much more about this than I do.
Tore

[tore]

Simon.
The group exhaust valve finishing touch.
Below is my assumption of the hullpassage for the group exhaustvalve. No doubt the outlet is flanged to the inner pressurehull and nuts are locked by lockingplates,see photo below. The only place the pipebend can bypass the external exhaust pipeflange is outboard as indicated on the sketch. For the crossing of the next next flange ( mufflervalve,) the bend leaves the exhaustpipe on the top and goes to the bottom inboard of the mufflevalve housing. Further in the same way for the other flanges.
Tore

[NZSnowman]

[NZSnowman]

Tore, the drain line with the sight glass. Are we missing it or is it not on U-995?

http://www.uboatarchive.net/U-570Plate13.htm

[TopherVIIC]

Nice work Simon - as always! I like the pressure gauge. As an artist, I salute your bravery for taking on such a complicated piece!
Christopher

[NZSnowman]

Tore, in the photo "Exhaust Manifold.JPG" what is the single pressure gauge for? Should there be two of them?

[NZSnowman]

Tore, bottom left of this photo look like the Thereometer that this found near the bend, do you think it just fixed to the main exhuest pipe?

http://www.uboatarchive.net/U-570Plate13.htm

[tore]

Simon.
You have even introduced the grease connections on the group exhaust valve. I assume the pipes goes to a distributionpoint which is fed by the greasepump on the aft bulkhead. The manometer is of course mandatory on this point. Good work!
Tore

[tore]

Simon.
Sight glasses.
We have indeed not installed the sigth glasses. I have not been able to locate the glasses and presume they are there but further down near the funnel. This is the last check on the coolingwater before leaving the engineroom.
Tore

[tore]

Simon.
Thermometer.
 I think it is, good spotting!
Tore

[tore]

Simon
I have tried to find the photo Exhaustmanifold jpg. but in vain. Seems to be too many photos and no system could you just show it?
Tore

[NZSnowman]

Simon
I have tried to find the photo Exhaustmanifold jpg. but in vain. Seems to be too many photos and no system could you just show it?
Tore

[tore]

Simon.
Manometer-
Thanks. I don`t believe this has anything to do with the exhaustmanifold. The manometer is marked at 12 atu which is the normal working pressure for the LP air supply. I
would assume it is the supply air for the main engine clutches.
Tore

[NZSnowman]

Simon.
You have even introduced the grease connections on the group exhaust valve. I assume the pipes goes to a distributionpoint which is fed by the greasepump on the aft bulkhead. The manometer is of course mandatory on this point. Good work!
Tore

Starting to add this system, but it hard as there areas of it that are missing in photo's 

[NZSnowman]

Simon.
Manometer-
Thanks. I don`t believe this has anything to do with the exhaustmanifold. The manometer is marked at 12 atu which is the normal working pressure for the LP air supply. I
would assume it is the supply air for the main engine clutches.
Tore

Main engine clutches.

Next on the long list, likely to start this in about two weeks 

[tore]

Simon
Main engine clutches.
I don`t believe the clutches are going to cause to much problem, I guess you are only to draw the visible parts. I `ll put up a  sketch showing how the system works for a better understanding as it makes it easier to draw.
Tore

[tore]

Simon.
Greaselines.
I agree the greaselines are not easy to follow. I don`t believe the pipes are fitted in a very strict pattern and  you would probably find variation from boat to boat,so I would suggest you put the pipes where it is natural to allocate same,, and start with the known points. I believe there are two pipes out of the pump , I assume they are the port and starboard supply pipes as you have only one grease pump in this area. For each side, somewhere between the pump and the external selector valve you should have a distributor block, normally just a block without a selector, from this block you have one pipe to the external distributor and two pipes to the group exhaustvalve. I believe the rest of the grease points have greasecups like the residue ballast vent.
Tore

[tore]

Simon.
I have to correct my last post , the group exhaustvalves have  locally placed greasecups with a distributor as can be seen on the u historia photo. I guess this makes life a bit easier as the two outgoing pipes would then be to port and starboard outboard grease selector. Thus all the internal grease points in this area have greasecups and distributors locally placed like the residue venting valves.
Tore

[tore]

Simon.
Engine clutches.
Allthough you are planning to start with the clutches in about two weeks time I shall give a short description of the system.
 The clutch is a double cone frictionclutch operated pneumatic/hydraulic by linkages. Air of 12 atu comes from two small flasks ( not identified by me) to a distribution cock (red handle on the aft bulkhead) which direct two air pipes (in and out) to a hydraulic cylinder fixed to the aft bulkhead. The actuating piston in the cylinder has a pistonrod with bore connected to the actuating lever (yellow). This lever is has a "hinge" in the bilge and engages half way down to a shaftsleeve (light green) by a wheel. Moving the actuating lever back and forth slides the shaftsleeve which is connected to the inner linkage of the clutch and connect and disconnect the friction cones. The linkages consist of a crankbell lever which snap the cones in a locked in position. On the u historia photo you see the wormrod and the pistonrod fixed to a yoke having two guide rods. At the ends of the guiderods are some peculiar "nuts". These are spring loaded endstoppers which when the linkage snaps in position pushes the actuating lever a fraction back to release the engagement at the shaft slide to prevent a possible hotrunning. The clutch can be operated by a handwheel for emergency. Turning the handwheel turns the wormshaft (red)  which moves the (nut,pink) inside the the pistonrod. The nut moves in a slot to allow free movement of the pistonrod under normal circumstances, in emergency the "nut"engage the ends of the slot and moves the rod in and out.
Tore

[tore]

Simon.
Engine clutches.
I just realized I forgot to put in my usual reservation: the above is my assumption . I migth add that the hydraulic air piston system is a bit uncertain.
Tore

[tore]

Simon
Pneumatic/hydraulic clutch system.
It might be I am mixing up with systems on other subs, but I base my assumption on that the pipes in and out of the operating cylinder are bigger than that of the airpipes to and from the operating handle. It looks as the pipes of the operating cylinder are going down whereas the air pipes are going up, a bit confusing .
The usual arrangement for this system has a floating corkplate as a barrier between the air and the oil ind the actuating cylinder. See sketch below.
Tore

[tore]

Simon.
Checking the u historia photo of the starboard clutch I believe I found one of the small air/ oil flasks for the actuating piston. Way under the propellorshaft you can see the top of the flask and the two pipes.
Tore

[tore]

Simon
The sketch showing the working of the pneumatic/hydraulic piston rod and the handoperated wormrod was not very clear as the  wormrod end was too short and the slot too long so here is a correction.
Tore

[TopherVIIC]

Simon and Tore -
I do not know if you have seen this wreck-dive video of U-251 at http://www.youtube.com/watch?v=Gw3EsX5bh4g
The dive footage shows extensive damage but there are sections where the divers are over the aft casement. Surprisingly, there is a lot of detail of the exhaust sections  between the casement and pressure hull, as well as air induction that you can pick out. B-)
Especially around 6:30+ 
Christopher

[tore]

Christopher
Fantastic .I`ll certainly scrutinise the details tommorrow. Thanks a lot.
Tore

[tore]

Exhaustpipe expansion.
I had another look at the divingvideo of U-251 provided by Christopher and located the exhaust pipes outside the pressurehull. What strikes me is the relatively complex arrangement of connections  between the group exhaust valve, 90 degrees bend, muffler and sparkarrestor, all connections have a short visible part of an uncooled smaller pipe entering the next component.
This is not without any reason. As I briefly mentioned before, free heat expansion has to be provided for and the connections have an  flange for a "stuffingbox" allowing the pipe to expand freely into the next component. This uncooled exhaustpipe stub has a small diameter (no coolingjacket) which makes it is easier to provide such an expansion stuffing box . I guess you find the same arrangement for the exhaustmanifold.
Tore

[tore]

Diving video U-251.
Having been a hobby moviemaker of diving videos I appreciate a good shot like the above movie. It is astonishing how some submarine wrecks  rest nicely at the seabottom.
We lost one of our U class submarines with all hands, just outside the Norwegian  coast in a German minefield February 1943. In 1985 the wreck was discovered and below is a photo of same resting almost like a display. The wreck is of course a wargrave, forbidden to be explored by divers.
Tore

[TopherVIIC]

Tore -
Do you know if there are surviving records of the operational/refit history of the KNM Kaura when she was with Norwegian Navy? Where might one go to request such things, and do you think that those with such records might be forthcoming to information requests?
What base did you operate primarily from? Would her Home Port possibly have records?

I, for one, would be willing to sift through such records if it could provide us with insights to her.
Christopher

[tore]

Christopher.
I don`t believe there are any such records available. I have German records of U 995 from the war time. Her Norwegian time as a "front" submarine was fairly short I guess  some 4-5 years, I was on board half the time. She had a retrofit every 3 years. For the last years she was acting like a school sub.
We operated out of the submarine base in Trondheim Norway as from just after the war. The Germans  build two large submarinepens in Trondheim of which we used one. In March 1954 we moved to the a temporary submarine base in Bergen using an ex. US workshop and depotship as quarter till a new main permanent submarinebase was built near Bergen and ready February 1960.  The old submarines like KNM Kaura  U 995  were scrapped in the beginning of 1960 as 15 new submarines were built and put into service as from early 1960 till 1967 of course these submarines are all scrapped as well and replaced by new ones. I believe some records could be found at the main submarine base Haakonsvern in Bergen otherwise  The Norwegian Naval Museum , Horten, Norway might have some records how willing they are to give away records I have no idea.
Tore

[TopherVIIC]

Thanks Tore -
I will see what, if anything, I can find out. Of course, since you and Simon have The engine room covered - I am focusing on the bow. The more I look, the more I see differences from other boats that would be interesting to track.
I know boats like that are a symphony of change - so we keep digging!
Have a good weekend!
Christopher

[tore]

Christopher.
You are right about there are differences between the boats even having the same buildingyears. When I got another boat, KNM Kya ex U 926 in 1954 I noticed quite a difference allthough the basic was of course the same. The boats were built at a different yards which apparently had different solution to many details. The most visible difference was probably U 926 had the new type of compasshousing whereas U 995 had the old streamlined. When you go into details as you and Simon, you are bound to find discrepancies between the boats. Below you are photos of KNM Kaura and KNM Kya showing the differences. In addition to the compass housing deviations they had 2 and 3 deck containers respectively and different schnorkel locking pin. For some reason the German fitted  Laboe U 995 with the new type of compasshousing.
Tore

[tore]

Simon
Pneumatic/ hydraulic clutch system.
When checking the u historia photo of the dirtyoil handpump on port aft engineroom bulkhead evidence is found that the airsupply to the clutch switching handle is coming from the top and the pipes out to the flasks are going down somewhere to the bilge thus the confusing photo from the starbord side is cleared up. I believe we can assume it is a pneumatic /hydraulic switching system with airpipes going down to the small flasks below the propeller shaft and oil supply/return  via sligthly larger pipes to the actuating cylinder.
Tore

[tore]

Simon.
Operating handle for clutches.
The operating handles for the clutches, painted red on U 995 are of the standard type sliding handle connected to a plug which fit into a slot locking the handle and cock in position. On the nameplate I have been able to decipher some of the text inboard reading EINR..... the rest is unclear to me, but I guess moving the handle inboard is clutching in.
Tore

[tore]

Simon.
Clutch handle.
Knowing your liking for details, I show you the locking of the clutchhandle as fitted on U 995. On the port engine the nameplate is gone and the handle is loose and placed upside down, by that displaying the plug which fit into the namedisc shown on starboard engine. The handle is springloaded and you raise the sliding handle by having your thumb on the protruding nob. Just a minor detail for your pleasure .
Tore

[NZSnowman]

Added the deck plating today

[tore]

Simon.
Too bad to cover up all the hard work you had with the piping . Just a small detail, if you look at the u historia photo of the reserve luboil/fueltransfer pump forward port
side you`ll see the deckplates don`t have the red marked plate below. I know your lay out is according to some drawings, but the original luboil-and coolingwater pipes does not allow for this plate on poor old U 995. It could of course be one of these deviations previously mentioned.
Tore

[tore]

Simon.
Deckplates.
I checked a photo I had of the plates of u 995 presumeably from 1965- 70 so most probably in the original execution. An accurate position of the deck operated valves are hard to established, but a  view of the diamond shaped pattern is quite clear. Another detail is the step down which seems to be aft of the vibration damper.
Tore

[NZSnowman]

Simon.
Deckplates.
I checked a photo I had of the plates of u 995 presumeably from 1965- 70 so most probably in the original execution. An accurate position of the deck operated valves are hard to established, but a  view of the diamond shaped pattern is quite clear. Another detail is the step down which seems to be aft of the vibration damper.
Tore

Very interesting!
 
Tore, do you think its original German floor plating or original floor plating layout?
 
I had believed the original German floor plating was pattern as I have drawn with a

[tore]

Simon.
I cannot imagine the floorplates were changed in Norway and then changed in Germany once more, I would say it is a pretty good chance the diamond pattern are the original plates.
Tore

[tore]

Simon.
I just checked another photo of the engine room deckplates of U 178 and by treating the photo in photoshop I got the pattern of the plates and they are diamond shaped as well as can be seen on the picture below.
Tore

[NZSnowman]

I just checked my books, and found two pictures of the engine floor plate; One with 

[tore]

Simon.
Just another confirmation of these deviations which we have seen so many of.
Tore

[NZSnowman]

Tore, I can not found any photo's that show the foot of the rocker arm base (yellow). There one bolt at the front but I imagine you would need more than one large bolt to hold this on to the engine.

Tore, can you give me any idea of the shape of the foot and how many bolts are needed?   

[tore]

Simon.
The visible bolt on the exhaust/ inletvalve pedestal is taking the peak of the load but I am sure there must be a bolt on the other side. Normally it should be a bolt of the same size, but this second bolt could from a stress point of view be smaller although that would be unconventional. I`ll keep looking to see if I can find a solution.
Tore

[NZSnowman]

Simon.
The visible bolt on the exhaust/ inletvalve pedestal is taking the peak of the load but I am sure there must be a bolt on the other side. Normally it should be a bolt of the same size, but this second bolt could from a stress point of view be smaller although that would be unconventional. I`ll keep looking to see if I can find a solution.
Tore

Tore, I was thinking of a 3 bolt fixs (green). Do you think it would only be two (green and orange)?

[tore]

Simon.
May be two smaller (green) will do particularly taking the shape of the base plate into account.
Tore

[NZSnowman]

Added the missing locking ring

Old drawing - left; New drawing - right

[NZSnowman]

Simon
We are entering a gray zone for me, I can not remember how the airduct from the Roots blower is entering the airmanifold. It is annoying because I my shelf dismantled the blower entirely ( some 60 years ago) . I have superimposed your drawing on top of a layout drawing  to figure out the arrangement. The confusion is on an appearant large ( yellow coloured ) square opening which I thought would be the inlet to the manifold. I just show you the picture may be you have more materials helping you to figure out the connection.
Tore

Tore, what is your suggest in how I should enter the airduct to in the Roots blower? Should I just extent the pipe across to the blower for now?

[tore]

Simon
Airflow Roots blower.
Below is a drawing where I have suggested the airflow (green) of the Roots blower.  This would mean that you just extend the air manifold  so it matches the blower casing, the airduct shall then be flanged vertically to the Roots airduct. ( my assumption). Yellow duct is inlet duct for the aft cylinder.
Tore

[NZSnowman]

Tore, just noted a 2nd hot sea water line running aft to the air compressor but only from the starboard engine.

[tore]

Simon.
Coolingwater/ corrosion protection.
The Plate 13 shows a combination of systems. The warm water supply to the galley and washbasins are primarily served by the header tank in the tower getting its warm water from the mufflercooling, allthough there is a connection from the engineroom to the galley.
The piping you questioned is connected to the anti corrosion system. The Germans used an anticorrosion oil which emulsified with the coolingwater and thus protected the exposed steel/iron against seawatercorrosion. We never used it. The system works as shown on the system sketch below. You injected the  anticorrosion oil when the cooling watersystem was not in service. Every so so often a barrel of the oil was connected to the hoseconnection at the coolingwater handpump and pumped in to the coolingsystem by hand. By cocks and valves you are able to direct the the oilflow to each of the engines, the exhaustmanifolds and the Junker compressor. The other cooling systems in the aft torpedoroom were not incorporated. The anticorrosion oil for the engines (yellow) is pumped by hand to the main cooling waterchest (valve e is shut) and flows via valve e1 to valve f at the luboilcooler, out at valve d1 and through the engine in the normal coolingwater way. At the group exhaustvalve the main overboard seavalve is shut and the cock f1 is in the crossover position, leading the oil to the main aux. cooling waterpipe which has valve i 1 shut and the oil returns to cock g at the handpump, which is put in the hose/dirty oil drain position and leaves the system.
 When you want to treat the Junker compressor you shut the cock f1( engine coolingwater return via main aux pipe) and the oil flows to the aft torpedoroom (purple pipe) enters the compressor cooling system by open cock 6, (valve c and valve 5 shut,) through the compressor and leave via cock f to the main aux coolingwater pipe as return to the dirty oil hose connection at the handpump. This should explain you smaller pipes and crossover.
Appart from the anti corrosion mode, the main aux cooling pipe is of course used as an ordinary coolingwater pipe for emergency supply to the aft torpedoroom when needed.
Somehow the system would not accept the sketch at 380KB jpg I`ll post it separately.
Tore

[NZSnowman]

Tore, thanks for the information

If this pipe what is located on the shipyard drawing is for the Coolingwater/corrosion.

What is the pipe I previously thought was for the Coolingwater/corrosion that runs along the port pressure hull for?

[tore]

Simon.
Anticorrosion piping.
I understand your confusion, if you remember a few weeks back we were dealing with the cooling waterpipes fitted to the aft engineroom bulkhead I could not find a pipe which according to the system plate 13 should be connected to the anti corrosion pipe see picture below missing pipe marked red. That`s when I realized plate 13 doesn`t match with the u 995 system. I believe the 1943 and later boats had altered the old anti corrosion system possibly by introducing a special smaller pipe for the treatment.
So my assumption would be: the large pipe going aft at outboard port side is the aux. main coolingpipe from the aux coolingpump in the engineroom and the smaller pipe on the shipyarddrawing from 1943? is the modified pipe for the anticorrosion. The challenge would be to hook the new system to the aft torpedoroom Junker compressor.
Tore

[tore]

Simon
This thread does not accept my pictures anymore saying the download is full. I`ll e-mail you the picture.

Tore

[NZSnowman]

Cooling water/Corrosion

[tore]

Simon.
 Very good
Have you been able to find the connecting points ?
Tore

[tore]

Simon
The exhaust / inlet valve pedestal.
Having checked the photos once more I believe the most probable way of fixing the pedestal would be two bolts, the one inboard is obvious and the other most probably in the open area as shown on the sketch. In addition each pedestal has two location pins as can be seen on the photo. 
Tore

[NZSnowman]

Simon
The exhaust / inlet valve pedestal.
Having checked the photos once more I believe the most probable way of fixing the pedestal would be two bolts, the one inboard is obvious and the other most probably in the open area as shown on the sketch. In addition each pedestal has two location pins as can be seen on the photo. 
Tore

[NZSnowman]

Top: Cooling water/Corrosion System; Bottom: All

[tore]

Simon.
Not bad in spite of outdated system sketches. Apart for that, this system works better no wonder they changed the old .
 
Tore

[NZSnowman]

Tore, is this a access hatch?

[tore]

Simon.
Yes I guess it is the access  to the torsional vibration damper.
Tore

[NZSnowman]

Rocker Arms & torsional vibration damper cover

[tore]

Simon.
Torsional vibration damper.
The torsional vibration damper might be an unknown device. In all reciprocating engines torsional vibrations occur which might increase in value and eventually reach levels were the stresses can brake the crankshaft. In order to prevent vibrations to build up, a torsional vibration damper is installed mostly  on the front of the engine and is basically consisting of two masses (rings) spring or hydraulically connected and the uneven massvibrations created by the combustionforces are"chopped up".
There are a number of different designs, below is one not necessarily identical to the type installed on the GW engine.. In general they require little maintenance.
Tore

[NZSnowman]

Tore, does this line just drain into the bilge?

[tore]

Simon.
The pipes shown are connected to cocks on the highest points of the ME cooling watersystem and is the ME main venting leading to funnels on a common pipe to the bilge. This  system is easy to mix up with a pipe of same size and in same area going along the engine as well. This pipe is connected to each cooled exhaust outlet bend with no cocks or valves.
Tore

[NZSnowman]

Tore, just finishing off lose end of pipes in my drawing.

I was wondering about this line. Is it a vent line? And went does it go?

[NZSnowman]

Tore, just checking about this line; drain line from the reducing valve and running to the dirty oil tank?

[tore]

Tore, just finishing off lose end of pipes in my drawing.

I was wondering about this line. Is it a vent line? And went does it go?

Simon.
I do not believe it is a ventpipe because it is too low and has no shut off cocks. If you look at plate 13 you`ll see a coolingwater pipe going along the engine inboard. There is no such pipe on the engine, I believe it soul go outboard and is the pipe discussed marked red below. As the pipe has a flow of coolingwater it is hooked up to the outlet somehow, plate 13 does not fit very well, but I guess it connect somewhere down in the bilge close to the aft bulkhead, I guess we have to look in this area.
Tore

[tore]

Tore, just checking about this line; drain line from the reducing valve and running to the dirty oil tank?

Simon.
I don`t believe to the dirty oiltank, more probably to the relevant system oiltank as it is clean oil.
Tore

[tore]

Simon.
Luboil reducing valve.
Are you sure this line is for draining and not manometer?-
Tore

[NZSnowman]

Simon.
Luboil reducing valve.
Are you sure this line is for draining and not manometer?-
Tore

Tore, do you think it could be for a manometer? There no manometer marked on plate 14 around this reducing valve

[NZSnowman]

Tore, just finishing off lose end of pipes in my drawing.

I was wondering about this line. Is it a vent line? And went does it go?

Simon.
I do not believe it is a ventpipe because it is too low and has no shut off cocks. If you look at plate 13 you`ll see a coolingwater pipe going along the engine inboard. There is no such pipe on the engine, I believe it soul go outboard and is the pipe discussed marked red below. As the pipe has a flow of coolingwater it is hooked up to the outlet somehow, plate 13 does not fit very well, but I guess it connect somewhere down in the bilge close to the aft bulkhead, I guess we have to look in this area.
Tore

Tore, I think the chance of finding this connection point would be nearly impossible with the photo

[tore]

Simon.
I believe you don`t have to wait hooking up the pipeline. Somehow I think you have connected the exhaust manifold venting pipes to the main coolingwater outlet pipe instead of  the drain funnel. If you put the ventingpipe to the funnel and the exhaust cooling header outletpipe where the venting pipe is at present, the system will work. See sketch below.
Tore

[tore]

Simon.
Luboil reducing valve.
I guess the pipe is a manometerpipe. Below is the system, there are two small pipe connections on the reducing valve, the large is the returnpipe to the system oiltank joining the overflowpipe from the luboil cooler and the luboilpump (yellow). The smaller pipe must be a manometerpipe, you want definitely to know that this important valve works with the correct pressure. There is a manometer at the end of the engine as well.
Tore

[NZSnowman]

Simon.
Luboil reducing valve.
I guess the pipe is a manometerpipe. Below is the system, there are two small pipe connections on the reducing valve, the large is the returnpipe to the system oiltank joining the overflowpipe from the luboil cooler and the luboilpump (yellow). The smaller pipe must be a manometerpipe, you want definitely to know that this important valve works with the correct pressure. There is a manometer at the end of the engine as well.
Tore

Tore, I don't believe this small pipe (yellow) is connected to the bigger pipe

[NZSnowman]

Tore, while looking in to the other pipe above. I was able to track and trail the green pipe with photo's and the shipyard drawing (red arrow = Relief valve 'h') (purple arrow = the section you are see in photo's).

I am now trying to trail the main outlet pipe from the pump (you can see it under the red arrow and ends at the black round circle) I am now trying to decide where to drop is pipe down 1, 2, or 3

[tore]

Simon.
Lubeoil reducing valve.
I agree with you the lager pipe is not connected to the reducingvalve. I shall have to modify my assumption and remove the manometer as I believe the only small pipe
out from the valve have to be the return pipe joining the pipe from the lubeoil cooler and pumprelieve valve to the system oiltank of the relevant engine.
Tore

[tore]

Simon
Luboil reliefvalve drain.
I guess it is easy to get confused here. Just remember the drain from luboil cooler, reducingvalve 3>1.5 atu and the relief valve are all connecting and returns via a common pipe to the relevant system tank. The outlet pipe just before the main luboil pumpsuction flange is a connection to the lub oil discharge pipe. For being a simple gearpump, the luboil pump looks a bit complicated, I believe it is a left over from the direct reversible engine where the gearpump had to operate in both turning direction.
Tore

[NZSnowman]

Tore, if you have time could you please check my pipes. Also I can not work out one of them.

Thanks, Simon.

[tore]

Simon.
As far as I can see you got  it allright. On the cross section shipyard drawing  "spant 26  von vorn gesehen" you shall find the luboil reducing valve ( 3>1.5 atu) spill off pipe P 14/17connecting to the pipe P 14/19 underneath the suction valve of the luboil pump. The pipe marked with yellow question marks is the main coolingwater supplypipe to the engine. Note the they have changed the original thermometers with smaller modern brass thermometer on several places.
Tore

[tore]

Simon.
The luboil pump being a gearpump would have a opposite inlet and outlet when the direction of rotation is reversed. As port and starboard engines have different direction of rotation  but using the same pump you`ll see the pipeconnections are placed on different sides of the pumps, that`s why you have  4 connections on the pumphousing and blanked off one of them. Another detail to be included is the revolution counter on the top of the pumphousing.
Tore

[NZSnowman]

Simon.
The pipe marked with yellow question marks is the main coolingwater supplypipe to the engine...

I have been trying to put lub oil in this pipe, no wonder why I can not get it to work

[tore]

Simon.
Mixing oil and water is OK if you use anticorrosion oil but not with lubeoil.
Tore

[NZSnowman]

Simon.
As far as I can see you got  it allright...

Thanks Tore! I should have some new drawings for you toworrow.

The number of pipes around the front of the engines is complex. It very hard to get all the different pipes to fit and also to get them to go correctly under or over the other pipes. I had to spited the engine drawing into two different layers today as you can have parts of the engine that are above the decking and parts of it that are below the decking. 

[tore]

Off  topics.
To day it is published by the Norwegian oilcompany Statoil looking for a underwater track to put a gasfield pipe, that they found an U boatwreck laying at 250 m only 2000 m from the famous U-864 ( the mercury boat). The wreck is assumed by the Norwegian Maritime museum to be of U-486 which was sunk by  the British submarine HMS Tapir April 12 1945. U 486 was delivered from Deutsche Werft March 22. 1944. She is reported to have sunk the troopcarrier Leopoldville where 800 US soliders lost their life 2 Royal Navy frigates were on her sinkinglist as well.
Tore

[NZSnowman]

Tore, extreme piping!

Here is the layout for just the 3 pipes that you can see below P14/13 = Orange; P14/5 = Red &  P14/6 = Blue)




Fig. 1. Three pipes and torsional vibration damper cover.


Fig. 2. Torsional vibration damper cover remove.


Fig. 3. I have remove the Orange pipe and some of the LO lines so you can see how the blue lines connects to the valves.


Fig. 4. I have remove all but the red lines.

[tore]

Simon.
Your pipe system seems to be OK to me. Just a matter of days before we can start up!
Tore

[tore]

Off topics.
U 486.
Further to my report of the find of U 486 follows a photo of the wreck and crew as well as SS Leopoldville which she torpedoed Christmas eve 1944. The troopship sank slowly (2 1/2 hours) in spite of that and due to holyday leaves,  rescue vessels without crew and mishandling almost 800 US troops lost unfortunately their lives.
Tore

[NZSnowman]

Next few pipes...

Pink = LO Cooler to Coll & Dist Manifold
Violet = Runs toward the pump (which I can not remember it name).
Green = from LO pump to pink line.
Yellow = from reducing valve to Green line.

[NZSnowman]

Simon.
Your pipe system seems to be OK to me. Just a matter of days before we can start up!
Tore

High pressure air starting system hookup and ready 

[tore]

Simon.
Don`t forget the handle on the starting air wheel!
Tore

[tore]

Simon.
Pipes.
Your new supply of spaghetti seems to me to be OK . One question though . On the pipe layout plate you have correctly placed the violet pipeline outboard and to the governorservo for the fuelrack. However before entering the servo you have two branch off to the Roots blower. Have you found these branch off pipes on some photos or drawings? The reason for the question is that this violet pipe is shortcutting the reducing valve 3>1.5 atu in order to supply the servo with oilpressure of 3 atu whereas the luboil pressure should be 1.5 atu. The lubrication points on the Roots blower are four bearings and the gear/timing gear,plus clutch which really do not need higher pressure than the rest of the lubrication points of the engine.
Tore

[NZSnowman]

Tore, yes I have a photo (below). You can clearly see the two lines to the Roots blower.

[tore]

Simon
Luboil 3 atu.
A very convincing photo. I cannot explain why the Roots blower has a higher luboil pressure, but I guess it would be on all the lubricating point of the blower not only the forward rotary vane bearings. Below I have marked the relevant luboil pipeinlets which I assume is then connected to the violet 3 atu luboilpipe.
Tore

[NZSnowman]

Lines for measuring instruments for LO Filter (Violet - Black - Violet)

[NZSnowman]

Piping around the torsional vibration damper cover - finish

Also fix the piping for the air starting system.

[tore]

Simon.
The pipes for the differential oilfilter manometer are placed where they should be. To me they look a bit larger than the impression I had, they do not deliver any oil like the pipe to the servo, just static pressure.  I believe they were small copperpipes.
Tore

[NZSnowman]

Floor cover & torsional vibration damper cover