Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Simon, another small detail. It seems to me that you have made the fuelsupply pipe to the HP fuelpipe of copper, I believe it is of steel. The Laboe U 995 get a funny rusty look on the unpainted steelparts, see picture below where the steelhandles colour is identical to the fuel supplypipe whereas the real copperpipe has a different colour
Tore

[NZSnowman]

Simon
In addition to my last post the overhead drawing of the enginetop shows large circular objects between the cyl. covers inboard side. The engine is built up of caststeel pieces, the majors being the crankcase and the cylinderblocks. They are bolted together by mean of long tiebolts with nuts on the lower parts ( in the crankcase) and heads on top of the cyl. block. There are alltogether 14 tiebolts 7 inboard and 7 outboard, on the drawing 7 inboard and 1 outboard are visible. In order not to obstruct the fitting of the cylindercovers, the heads of the tierods are fitted in  recesses in the cylinderblock, the recesses are covered by  steelplates and that is the circles you see on the overhead drawing. By the way, putting the inboard cylindercover studs ( the short ones) in  recesses makes it possible to accommodate the rockerarm pedestals on the top.
Tore

Hi Tore

Again big thanks! I was going to ask you in a few days what this was on the engines. I have added the Tie bolts to my drawings. I also noted that I had missed them from the

[NZSnowman]

Simon, another small detail. It seems to me that you have made the fuelsupply pipe to the HP fuelpipe of copper, I believe it is of steel. The Laboe U 995 get a funny rusty look on the unpainted steelparts, see picture below where the steelhandles colour is identical to the fuel supplypipe whereas the real copperpipe has a different colour
Tore

Tore, thanks. I realise they are steel just have not found the time to change the colour yet. On the

[NZSnowman]

Final?  The details of cyl cover top. One item remains to be identified, the safetyvalve, which is a pressure reliefvalve and you can barely see the top protruding out of the cylindercover top. The place is indicated below.
The cooling watercock looks a bit strange, but it is because the function is you can lead the water out from the cylinderblock cooling either fully through the exhaustvalve (series) or partly ( parallel) depending upon the need.
Tore

Hi Tore

Thanks! I was going to ask you this question also Again added the new sub-system to my drawings.

[NZSnowman]

Simon. Excellent, this is going to be the best ( except for the design drawings) drawing of the GW M6V 40/46 engine made ever. A small detail, check the diameter of the HP fuelpipe in relation to the airpipes, particularly the controlair branch to the top of the startingair valve. It seems to me the fuelpipe is slightly too large or more probable the airpipes slightly too small.
Tore

Hi Tore
 
I am almost sure I know what pipes you are talking about, if so I also noted this and made the changes on the

[tore]

Simon. We are almost there I believe. Something with the drawing projection is a bit strange to me. You obviously are basing your first drawings on port  engine aft. The topview of the cover is  placing the valverods outboard, to me this is a different way of projecting. In order to prevent any misunderstanding I post a drawing to explain what I mean.
Tore

[tore]

Simon. By the way I guess I somewhere mentioned that the inlet and exhaustvalves were turned 180 degrees, I have to correct that. The exhaustvalves are forward of the inlet valves on both engines. See picture.
Tore

[tore]

Simon.
Pipedimensions.
May be a closer look into the starting airpipe branch off to the top of the startingvalve, and the main starting air supply pipe in relation to the HP fuelpipe would be worth while. See picture.
Tore

[tore]

Simon.
Cylindercover cooling.
I realize we haven`t gone into details on this subject. The coolingwater enter the cylindercover via pipebends from the cylinder coolingjackets.  The pipebends would the only visible part ( if at all). Out of the cover it enters the series/parallel coolingwater cock ( blue) which allow the water to go to the exhaustvalve cage, either partly (parallel) or all (series) depending upon the temperate reading on the thermometer, it is manually controlled.
The water from the cock then goes to the exhaust manifold coolingspace. The funny looking "spring" on the photo is, I believe, the handle for the cock, the springshape is a typical 1920/30 solution for heat insulation. The details to be seen are a bit unclear to me on this.
Tore   

[tore]

Simon.
Cyl cover- exhaustvalve piping.
Below is a picture showing my proposal of the piping, it might be the cockarrangement is different. This would be starboard engine, forward to the right. The cockhandle is on the other side of the cock and the ventingpipe ( blue ) is missing I believe.
Tore

[tore]

Simon.
Fuel supply pipe to HP pumps.
On your drawing it seems that somehow the collecting drain pipe is connected both to the lubeoil drain pipe from the governor servomotor and the fuel supply pipe to the HP fuelpumps. The collecting drainpipe runs along the engine about where the cylindercovers meets the cylinderblock and collect drain from each cylindercover via funnels. I guess it possibly ends up in the dirty lubeoil tank underneath the floorplates. Anyhow this relatively simple drainpipe has nothing to do with the other two systems. See drawing below.
Tore

[NZSnowman]

Simon.
Cylindercover cooling.
I realize we haven`t gone into details on this subject. The coolingwater enter the cylindercover via pipebends from the cylinder coolingjackets.  The pipebends would the only visible part ( if at all). Out of the cover it enters the series/parallel coolingwater cock ( blue) which allow the water to go to the exhaustvalve cage, either partly (parallel) or all (series) depending upon the temperate reading on the thermometer, it is manually controlled.
The water from the cock then goes to the exhaust manifold coolingspace. The funny looking "spring" on the photo is, I believe, the handle for the cock, the springshape is a typical 1920/30 solution for heat insulation. The details to be seen are a bit unclear to me on this.
Tore

Hi Tore

I am trying to sort out this handle. In the photo below you can see a handle on the exhaust outlet between the flange and the water cooling pipe. Do you think this is the same 'spring shape' handle you are talking about?

[tore]

Simon.
Cylindercover cooling.
I realize we haven`t gone into details on this subject. The coolingwater enter the cylindercover via pipebends from the cylinder coolingjackets.  The pipebends would the only visible part ( if at all). Out of the cover it enters the series/parallel coolingwater cock ( blue) which allow the water to go to the exhaustvalve cage, either partly (parallel) or all (series) depending upon the temperate reading on the thermometer, it is manually controlled.
The water from the cock then goes to the exhaust manifold coolingspace. The funny looking "spring" on the photo is, I believe, the handle for the cock, the springshape is a typical 1920/30 solution for heat insulation. The details to be seen are a bit unclear to me on this.
Tore

Hi Tore

I am trying to sort out this handle. In the photo below you can see a handle on the exhaust outlet between the flange and the water cooling pipe. Do you think this is the same 'spring shape' handle you are talking about?

Simon.
This is a bit hard to be 100% sure about. Below I have tried to clarify by putting a mirror picture of stb engine next to the your picture of port engine. As you see it is a venting cock right where the pipebranch to the common venting pipe should be and on the other side of the cooling bend is the pipebranch to the common ventpipe.
The only explanation I can give is that the common venting pipe has a shut of valve somewhere at the other end and that the extra ventingcock is a the end of the exhaustmanifold where air is likely to be trapped. By having the venting on this strategic place you can avoid to open up for all the venting which means a lot of water in the bilge. Anyhow I don`t think the end of the handle shown on your photo has anything to do with this, but is a handle placed on the opposite side of the series/parallel exhaustvalve cooling cock. For some reason not equipped with heat insulation handle.
Tore

[tore]

Simon
Just a small correction to my picture I see I have marked the main startingair pipe as a starting air valve, sorry.
Tore

[NZSnowman]

Simon.
Cylindercover cooling.
I realize we haven`t gone into details on this subject. The coolingwater enter the cylindercover via pipebends from the cylinder coolingjackets.  The pipebends would the only visible part ( if at all). Out of the cover it enters the series/parallel coolingwater cock ( blue) which allow the water to go to the exhaustvalve cage, either partly (parallel) or all (series) depending upon the temperate reading on the thermometer, it is manually controlled.
The water from the cock then goes to the exhaust manifold coolingspace. The funny looking "spring" on the photo is, I believe, the handle for the cock, the springshape is a typical 1920/30 solution for heat insulation. The details to be seen are a bit unclear to me on this.
Tore

Hi Tore

I am trying to sort out this handle. In the photo below you can see a handle on the exhaust outlet between the flange and the water cooling pipe. Do you think this is the same 'spring shape' handle you are talking about?

Anyhow I don`t think the end of the handle shown on your photo has anything to do with this, but is a handle placed on the opposite side of the series/parallel exhaustvalve cooling cock. For some reason not equipped with heat insulation handle

I now see that you are talking about, and I think you are right. Below is a better view of the series/parallel exhaust valve, you can see where this handle would attach to. Also you can see the other handle better.



PS. Made a lot of changes to my drawing today, listed below. Will post pictures in the morning, off to bed now

• Increase the pipe dimension of the Starting Air Main Supple on the

[tore]

Simon.
Looking forward to seeing your new drawing.
Tore

[tore]

Simon.
Insulated handle.
I `m still not 100% sure about the purpose of this cock. Being a cooling water cock/vent it shouldn`t be necessary to have such a heat insulated handle, it would be more likely for an exhaustcock. But right now I cannot remember or see the use for exhaust cocks on each inlet to the exhaust manifold as you have exhaust thermometer pockets. You probably should just draw it, if I get ideas I`ll let you know. Below is a picture I made of the handle in case you are not familiar with the design.
Tore

[NZSnowman]

Hi Tore

I know that purple is the safety valve, but what is green?

[tore]

Simon.
A very good question. The green arrow point to the safetyvalve, if you see the drawing below, the startingvalve, fuelvalve and safetyvalve are placed on the centerline in the cross section drawing, which put a new question forward what`s in the place were we put the safetyvalve in the beginning? If you look at the drawing nothing protrude out of the cylinder covertop, and the object is outside the combustion space, e.g. cylinder. I`m inclined to believe this might be a cover for a castingcore opening in the cylindercover coolingspace. So I guess you can put the safetyvalve in the centerline and just indicate a cover where we erroneously placed the safetyvalve in the beginning.
Tore

[tore]

Simon.
Another idea struck me, probably more correct. The cylindercovers are the same on both engines but turned 180 degrees on the other engine. The watercooled exhaustvalves are forward of the inletvalves on both engines. Everything  which are in the centerline are OK and need not to be changed. The exhaust valvecasing and the inlet valvecasing are identical and fit in both valverecesses in the cover.When the covers for the other engine are turned 180 degrees the only extra opening in the cover has to be the coolingwater opening for the exhaustvalve casing and that matches exactly. The  plate in the cylindercover is the cover for the extra coolingwater connection to the exhaustvalve cage to be used when the cyl. cover is turned.
Tore

[NZSnowman]

Simon.
A very good question. The green arrow point to the safetyvalve, if you see the drawing below, the startingvalve, fuelvalve and safetyvalve are placed on the centerline in the cross section drawing, which put a new question forward what`s in the place were we put the safetyvalve in the beginning? If you look at the drawing nothing protrude out of the cylinder covertop, and the object is outside the combustion space, e.g. cylinder. I`m inclined to believe this might be a cover for a castingcore opening in the cylindercover coolingspace. So I guess you can put the safetyvalve in the centerline and just indicate a cover where we erroneously placed the safetyvalve in the beginning.
Tore

Hi Tore

When I was adding the safety valve to the drawing I thought it was centre line. I will update my drawing.

[tore]

Simon very good. I`m absolutely sure my last theory is correct. The superfluous opening in the cylindercover is for the exhaustvalve cooling if the cover is placed on the other engine.
Tore

[tore]

Simon.
Studying you last drawing I`m not sure about the placing  of the cock with the springhandle. I assume the drawing is stb aft. If you look at my drawing below I believe the
 cocks are placed aft of the coolingbends. On the aft cylinder the springhandle is missing. May be you drawing isn`t updated yet.
Tore

[tore]

Direct reversible engine.
In all descriptions on the dieselengines of the VIIc (GW and MAN) a direct reversible system is mentioned. On the drawings of the diesel a large cylinder is shown outboard next to the maneuvering stand, this is the reversing cylinder. On some photos the reversing cylinder can be seen. The most common way of maneuvering a submarine is by E-motors, in the RN and many other navies. On photos of the  on the U 995 engines you don`t see the reversing cylinder because the engines were not direct reversible, neither were the U 926 and U 1203 and these submarines were maneuvering by E-motors. My idea Simon is that all the newer VIIc diesel engines were not direct reversible and you should ignore this device on you U 1308 drawings. Below is a picture showing what I`m trying to say.
Tore

[NZSnowman]

Simon.
A very good question. The green arrow point to the safetyvalve, if you see the drawing below, the startingvalve, fuelvalve and safetyvalve are placed on the centerline in the cross section drawing, which put a new question forward what`s in the place were we put the safetyvalve in the beginning? If you look at the drawing nothing protrude out of the cylinder covertop, and the object is outside the combustion space, e.g. cylinder. I`m inclined to believe this might be a cover for a castingcore opening in the cylindercover coolingspace. So I guess you can put the safetyvalve in the centerline and just indicate a cover where we erroneously placed the safetyvalve in the beginning.
Tore

Fixed and updated

[NZSnowman]

Simon.
Another idea struck me, probably more correct. The cylindercovers are the same on both engines but turned 180 degrees on the other engine. The watercooled exhaustvalves are forward of the inletvalves on both engines. Everything  which are in the centerline are OK and need not to be changed. The exhaust valvecasing and the inlet valvecasing are identical and fit in both valverecesses in the cover.When the covers for the other engine are turned 180 degrees the only extra opening in the cover has to be the coolingwater opening for the exhaustvalve casing and that matches exactly. The  plate in the cylindercover is the cover for the extra coolingwater connection to the exhaustvalve cage to be used when the cyl. cover is turned.
Tore

Fixed and updated

[NZSnowman]

Simon.
Cyl cover- exhaustvalve piping.
Below is a picture showing my proposal of the piping, it might be the cockarrangement is different. This would be starboard engine, forward to the right. The cockhandle is on the other side of the cock and the ventingpipe ( blue ) is missing I believe.
Tore

Fixed and updated 

[tore]

You have been busy,I bet by now your drawing would give a very interesting top view look, in fact as accurate and a standard never seen before. But a lot remains to be done on the other sides of the engine,piping,airduct,supercharger, maneuvringstand exhaust ducts with pneumatic valvegrinder etc. A lot of fun ahead.
Tore

[NZSnowman]

Hi Tore

Can you remember how the rocker arm base was attached to the head? I can see one large bolt in the front, are there any other bolts holding it down?

Thanks, Simon.

[tore]

Hi Tore

Can you remember how the rocker arm base was attached to the head? I can see one large bolt in the front, are there any other bolts holding it down?

Thanks, Simon.

Simon. As previously said the rocker arm pedestal sit on the top of the recess for the inboard cylindercover short studs so no fixingstuds can be place there. On the top of the cover is an "ear" protruding inboard and outside the cover. In this ear is a hole for the rocker pedestal basestud of some 20-25mm I believe. You can clearly see the "ear" with hole underneath on Kubische Panorama. On the other side probably a little closer to the pedestal centerline you got to have a similar stud, but that is a bit hard to be seen. Don`t be fooled by the small nuts for the guide positionscrews clearly to be seen. It might be there is a better quality overheadsketch somewhere to be seen.
Tore

[NZSnowman]

Hi Tore

While updating the drawing this morning, I noted that I had this rocker arm the wrong way around for the starboard side Correct layout below.

[NZSnowman]

Hi Tore

Can you remember how the rocker arm base was attached to the head? I can see one large bolt in the front, are there any other bolts holding it down?

Thanks, Simon.

Simon. As previously said the rocker arm pedestal sit on the top of the recess for the inboard cylindercover short studs so no fixingstuds can be place there. On the top of the cover is an "ear" protruding inboard and outside the cover. In this ear is a hole for the rocker pedestal basestud of some 20-25mm I believe. You can clearly see the "ear" with hole underneath on Kubische Panorama. On the other side probably a little closer to the pedestal centerline you got to have a similar stud, but that is a bit hard to be seen. Don`t be fooled by the small nuts for the guide positionscrews clearly to be seen. It might be there is a better quality overheadsketch somewhere to be seen.
Tore

Thanks, Tore.

I can see the outer bolt (purple), it

[tore]

Hi Tore

While updating the drawing this morning, I noted that I had this rocker arm the wrong way around for the starboard side Correct layout below.

Yes Simon.
For each stb cylinder on camshaftside from aft to fwd: inletvalve rod, HP fuelpump,starting rod, indicatorcock, fuelsupply bend to HP fuelpump and exhaustvalve rod.
Tore

[tore]

Simon two more pictures unfortunately of the same thing, I can`t see the other stud. I`ll sleep on it may be I get some idea tomorrow morning.
Tore

[NZSnowman]

Hi Tore

A couple of questions about the exhaust.

• What is the flange in the middle of the main exhaust pipe for?
• Why is there a small pipe that link between the two bigger exhaust pipes?

Thanks, Simon.

[NZSnowman]

Hi Tore

Found a small error on the exhaust flange which I have fixed this afternoon. Also no drawing tomorrow as I am off to work tomorrow, will post a big update on my drawing very soon.

Simon

[tore]

Hi Tore

A couple of questions about the exhaust.

• What is the flange in the middle of the main exhaust pipe for?
• Why is there a small pipe that link between the two bigger exhaust pipes?

Thanks, Simon.

Simon.
The exhaustmanifold is a fairly complicated doublewall ( allowing for the coolingspace ) cast piece. It is split into two parts as the cylinderblock, and bolted together by a flange in the middle. The coolingwater from the two parts is blocked by the flange and has to be bypassed by the coolingwater bend.
At the fwd end of the exhaustmanifold is a reliefvalve and a pipeflange which  is the pipe connection to the suctionside of the coolingwater pump  allowing warm water return to the system. See drawing. Don`t take the system sketch as drawn it`s merely a principle rather than a workingdrawing as you see.
Tore

[SnakeDoc]

Hi Tore


I have got some off-topic question. I know, that on KNM Kaura were some electric power points (outlets), which were connected to the boat's electric network (lightning circuit, which was powered by 110 V - despite of battery output voltage changes - by means of automatic voltage regulator). What kind of equipment could be connected to these outlets?


And one more question - do you remember, what kind of electronic device is it? It is located in the forward part of control room, at port site.



Is it German, war-time? Was it installed, when U-995 served in Norwegian Navy?


--
Thanks, regards
Maciek

[tore]

Hi Tore


I have got some off-topic question. I know, that on KNM Kaura were some electric power points (outlets), which were connected to the boat's electric network (lightning circuit, which was powered by 110 V - despite of battery output voltage changes - by means of automatic voltage regulator). What kind of equipment could be connected to these outlets?


And one more question - do you remember, what kind of electronic device is it? It is located in the forward part of control room, at port site.



Is it German, war-time? Was it installed, when U-995 served in Norwegian Navy?


--
Thanks, regards
Maciek

Hi Maciek
I`m not sure I understand you question 100%. If you mean outlet in living quarters, we had very few. Some could be used for transportable lamps but really no uncontrolled electric consumption occurred. We did not have any personal electric devices in those days. I t might be that later somebody installed outlets for waterheater and charging of electric razors. The only outlet we installed in my time was bulbs in the cabinets for protecting our best uniforms to go mouldy. I do not believe the germans originally had many outlet for personal use.
Tore

[tore]

Maciek
Electronics in the control room. I`m a bit out of my field right now, but I believe the electronic stack next to the navigation table contains mainly the S- geraet (Sondergeraet fuer Aktive Schallortung ) active Sonar and KBD (Kristall Drehbasisgeraet) passive turnable crystal hydrophones which is passive Sonar. The equipment was indeed very much used by us as originally installed. Later however I  believe they installed the  Balcon Geraet which probably would required another electronic stack.
Tore

[SnakeDoc]

I`m not sure I understand you question 100%. If you mean outlet in living quarters, we had very few. Some could be used for transportable lamps but really no uncontrolled electric consumption occurred. We did not have any personal electric devices in those days. I t might be that later somebody installed outlets for waterheater and charging of electric razors. The only outlet we installed in my time was bulbs in the cabinets for protecting our best uniforms to go mouldy. I do not believe the germans originally had many outlet for personal use.

Well, this is what I wanted to know. I was wondering, if other devices (other than lamps and ie electric heaters) were in use - for example electrically power tools (I know, there were pneumatic driven, but this is example). What kind of outlets were they? Domestic type (with some water protection)?


--
Thanks, regards
Maciek

[tore]

Hi Maciek.
I cannot remember we had any electric power tools except for a drill, I guess they were splashproof very much domestic types, but that could be norwegian installed, hard to say though as we use DIN standard as well. We used sometimes pneumatic tools. Otherwise I really cannot remember we used the few outlets very much.
Tore

[SnakeDoc]

Tore,

Electronics in the control room. I`m a bit out of my field right now, but I believe the electronic stack next to the navigation table contains mainly the S- geraet (Sondergeraet fuer Aktive Schallortung ) active Sonar and KBD (Kristall Drehbasisgeraet) passive turnable crystal hydrophones which is passive Sonar. The equipment was indeed very much used by us as originally installed. Later however I  believe they installed the  Balcon Geraet which probably would required another electronic stack.

It's interesting. So on board of KNM Kaura were installed both S-Ger

[tore]

Simon.
I don`t know how many details your next drawing would incorporate but trying to be a bit ahead I wonder if you have noticed the small cylinder between ME Cylinder 1 and 2. It looks almost like a HP fuelpump and is difficult to see. The cylinder is placed on a driptray on top of the camshaft casing having drainagepipe and on top of the cylinder is a handle. Unfortunately you don`t see any pipeconnection. I cannot say I remember this item but I believe it is a so called knifefilter for fueloil supply. The handle on the top is a handle for a brush inside the filter turning the handle cleans the filter. The reason for this extra filter in addition to the dual filters next to the fuel supplypump at the manoeuvring stand would be if the fuelsupply pump should fail you can by means of the threeway cocks at the stand, shortcut the system ( including the dual filter) and take
the fuelsupply from the daytank by gravity and you would need an extra filter in the supplyline to the HP pumps. I guess we shall get into that when your drawing comes to the the pipesystem. Anyhow just an info prior to you complete your present drawing. Below some photos trying to show these filters.
Tore

[tore]

In addition to the above. Unfortunately there are no correct drawings of the pipings on the engines, the systemdrawings keep showing the fuelsupply pump is driven from the camshaft drive aft wheraes the pump is driven from the crankshaft fwd.
Tore

[tore]

Tore,

Electronics in the control room. I`m a bit out of my field right now, but I believe the electronic stack next to the navigation table contains mainly the S- geraet (Sondergeraet fuer Aktive Schallortung ) active Sonar and KBD (Kristall Drehbasisgeraet) passive turnable crystal hydrophones which is passive Sonar. The equipment was indeed very much used by us as originally installed. Later however I  believe they installed the  Balcon Geraet which probably would required another electronic stack.

It's interesting. So on board of KNM Kaura were installed both S-Ger

[SnakeDoc]

Tore

As I said in the beginning this is a bit out of my field so you have to take the info with a pinch of salt. I thought we had both but for sure we had KBD. The balkongeraet was installed after my time so after 1956. I am a posting a picture of KNM Kauras bow and showing how the relevant area looked like in my time.

Thanks for your answer. On the photo you have posted, I think I can see the sender/receiver panel of S-Ger

[NZSnowman]

Maciek.
As I said in the beginning this is a bit out of my field so you have to take the info with a pinch of salt. I thought we had both but for sure we had KBD. The balkongeraet was installed after my time so after 1956. I am a posting a picture of KNM Kauras bow and showing how the relevant area looked like in my time.

Hi Tore
 
Over the last year I have completely change my mind about the balkongeraet on U-995/KNM Kauras. I believe you are right and that U-995 never had that pictured balkongeraet, there now more and more evidence to support this. I have been collection a little information on this and I want to write this up after Christmas.

[NZSnowman]

Hi Tore

In the drawing below you can see a smaller circle within the exhaust piping, do you think is could be the pipe for the cooling water?

[tore]

Simon I doubt this is the flange for the coolingwater it is too large and I presume we see the stb engine towards aft at the manifoldflange which is towards the exhaust manifold outlet end. I`ll see if can figure out what it could be.
Tore

[NZSnowman]

Simon I doubt this is the flange for the coolingwater it is too large and I presume we see the stb engine towards aft at the manifoldflange which is towards the exhaust manifold outlet end. I`ll see if can figure out what it could be.
Tore

Tore, I was more thinking about the smaller circle being the cooling water pipe that run inside the exhaust pipe.

[tore]

Simon.
I believe the cooling waterbends passes the flanges as shown on the drawings  below.
Tore

[tore]

Simon, as you see the casting of the exhaustmanifold is in such a way that the same pieces can be used for both stb and port engine, leaving a coolingwater flange at the fwd end. On the photo of the fwd end you see a pipe connected to this flange which I presume is a drain may be to the suction of the cooling waterpump.
Tore

[NZSnowman]

Tore, I am trying to work out where the cooling water goes. Does the used cooling water exit the pressure hull via the exhaust coupling and then vents somewhere under the deck?

[tore]

Hopefully this picture below makes it a bit clearer.
Tore

[tore]

Simon. The seacooling water diagram explain pretty much how it is done. Same principle as before , at every flange a cooling waterbend leads the water to the next coolingwater space. Where the main exhaust pipe passes the pressurehull you have the main exhaustvalve ( with the grinder) the whole valve casing with coolingspace enter through the hull. You have a pretty good picture of the section at U Historia.
Tore

[tore]

Simon.
Outboard coolingwater.
As can be seen from the below sketch the coolingwater enters the silencer outside the pressure hull and from there to the coolingwater headertank in the tower.
Tore

[NZSnowman]

Thanks Tore for the help. I had to check the alignment of my drawing. For example I just can not add my engine drawing to my U-boat drawing as I have to make sure that pipes align correctly, bolts holes match and under decking pipes align correctly to above deck.

Below in the two drawings you can see I had to align correctly the engine frame bolts hole and the cooling water piping

Fig. 1. U-Boat framing.

Fig. 2. U-Boat Engine.

[NZSnowman]

PS. Another example of alignments, in the drawings above is the open pipe flange for the Engine lubricating oil system. This pipe is currently out of alignment by about 30 mm at 1:1 scale so the two flanges will not match. You will never see is in the drawing as it under the engine but is hated to see oil leaking out of U-1308

[tore]

Simon.
Very interesting to see how it is done, it`s a big jigsawpuzzle. Seeing you drawing I assume the black rectangle toward the pressurehull is the airduct from the main engineroom airintake valve. To me it looks as if it is one frame too far forward, see my drawing below. The reason for such a duct was that in bad weather seawater filled the airduct via the main intakevalve in the towercasing and water gushed into the engineroom, you didn`t want that water into the ventilation system so it was lead down into the bilge.
Tore

[NZSnowman]

Simon.
Very interesting to see how it is done, it`s a big jigsawpuzzle. Seeing you drawing I assume the black rectangle toward the pressurehull is the airduct from the main engineroom airintake valve. To me it looks as if it is one frame too far forward, see my drawing below. The reason for such a duct was that in bad weather seawater filled the airduct via the main intakevalve in the towercasing and water gushed into the engineroom, you didn`t want that water into the ventilation system so it was lead down into the bilge.
Tore

Hi Tore

I just double check, and I have the air duct in the correct position.

Here today drawing, still lots to do

[SnakeDoc]

Simon

I have been collection a little information on this and I want to write this up after Christmas.

Looking forward to see your paper


--
Regards
Maciek

[tore]

Simon, very good. Just come to think of it, on various drawings it looks as if the exhaustmanifold flange is covered, which would be a must today. The reason is that this flange gets very hot and in case of a HP fueloil pipe burst fueloil might hit the flange causing a dangerous fire. I`m not sure of this point, if you have drawings/photos it is worth while to double check.
Tore

[tore]

Thanks Tore for the help. I had to check the alignment of my drawing. For example I just can not add my engine drawing to my U-boat drawing as I have to make sure that pipes align correctly, bolts holes match and under decking pipes align correctly to above deck.

Below in the two drawings you can see I had to align correctly the engine frame bolts hole and the cooling water piping

Fig. 1. U-Boat framing.


Fig. 2. U-Boat Engine.

Simon.
Just had a look at you ME lubeoil returnpipe and suggest  you hook up the collecting pipe for the return oil from the reliefvalve of lube oilpump and oilcooler as well as the vibrationdamper to the fwd lubeoil drainpipe from the main engine, see drawing below. The aft drain would have similar connections to the returnpipe from governor servomotor and supercharger.
Tore

[NZSnowman]

Simon
Exhaustmanifold.
Below I have indicated the components your inquired. The seacooling water from the engine ends up into the exhaust manifold coolingcasing, with all the bends and pipes, air could easily be trapped causing problems with the coolingsystem, hence the rather extensive deairation, which ends up in a common funnel aft in the engineroom. On the systemsketch below the principle is shown, howewer as you see the practical solution differ slightly from the systemsketch.
 The other item is the wire for remote reading of the exhaust temperature, for each cylinder, hence 6 wires. The 6 analog rectangular meters is very dominating at the manuevering stand.
Tore

Hi Tore

The 'common funnel aft in the engine room' Can you remember where is this funnel? As I would like to add it to the drawing.

[NZSnowman]

Hi Tore

I think I have found it (Orange), this would make sence as the water would drain right into the Drainage Piping (Blue)

[tore]

Simon I have been looking to see if I had any picture showing the common funnel, but unfortunately i didn`t find any. Mostly such a funnel or collecting tank is placed on the floorlevel or below. It is not really shaped like a funnel but more like a circular container with a lid where all the pipes disappeared, I think your sketch very well could be it.
Tore

[tore]

Simon.
Drain/deairation.
If you remember earlier this year we touched upon the same topic in relation to the handpump for the dirty oil and drainage in the same aerea. The idea behind this extensive collecting of spillage is of course to control the bilgewater your pumped overboard to assure you left no trails. You can split the system in two parts the presumable clean water and the oily liquid. The latter very often was drained via a funnel directly in to the dirty oil tank, the other oily mixture like the drains from the ME top, driptrays etc. could end up in a "cannister ". The cooling water drainage could contain oily liquid as the germans used to add an anti corrosive oil in the coolingwater. That`s why we have these numerous tiny pipes which are almost impossible to keep track of.
Tore

[NZSnowman]

Hi Tore

Going back to the air starting system. Orange 'X' is the valve a₁. The blue line is the outlet pipe, but what is yellow, this is the inlet? It sence very big for a inlet pipe from the HP bottles?

http://www.uboatarchive.net/U-570Plate15.htm

[tore]

Simon.
The " box" on your picture is the main startingvalve housing having 2 pipeconnections: one from the startingair  vessel and then the main supply to the starting air valves on the engine with a branch off to the starting handle from which there is a pipe to the top of the startingair valves on the engine, plus a manometer connection. I have tried to indicate where the pipes leads, but you really cannot see everything.
Tore

[NZSnowman]

Simon.
The " box" on your picture is the main startingvalve housing having 2 pipeconnections: one from the startingair  vessel and then the main supply to the starting air valves on the engine with a branch off to the starting handle from which there is a pipe to the top of the startingair valves on the engine, plus a manometer connection. I have tried to indicate where the pipes leads, but you really cannot see everything.
Tore

Thanks for the information I will update my drawing in the morning. I was able to find the connection for the pressure gauge, it is on the under side of the "Box". Would the gauge be attach somewhere near the pressure hull?

[tore]

Simon.
The manometer is situated in the instrument panel above the maneuvering stand, I think it is the manometer in the lower line outboard. The brassign  under would say "drueck anlassleitung" or something like that. I guess you can find a good picture in the engine roomchapter of U boat historia,  I think you should incorporate that panel in your drawing.
Tore

[tore]

Hi Tore

Going back to the air starting system. Orange 'X' is the valve a₁. The blue line is the outlet pipe, but what is yellow, this is the inlet? It sence very big for a inlet pipe from the HP bottles?

http://www.uboatarchive.net/U-570Plate15.htm

Simon coming back to your remarks on the diameters of the various HP pipelines. First of all don`t forget we are talking about relatively low pressure 30 kg/cm2. The  starting system consists of two pipe types, controlling - and consumption airpipes. If you see the supply air from the airvessel and the supplypipe to the startingvalves in the cylinders, the pipe is relatively large as it requires a lot of 30 kg/cm2 air to run a large diesel. The controlair pipe which is the small branch off to the startinghandle and further on to the top of the startingvalves have practically no consumption, it just put the piston on the top of the cylinder startingvalve a few mm down, thus a small pipe.
Tore

[NZSnowman]

Tore, thanks again for the information. I have completely redrawn the air supply system. I will post the new drawings in a hour or so, or first thing in the morning.

[NZSnowman]

Fig. 1. Side view of new Air Starting supply piping.


Fig. 2. Top view of new Air Starting supply piping.


Fig. 3. New Air Starting supply piping under the decking. The layout is correct but the some of the piping and the

[tore]

Simon I think this is excellent. The piping which was not on the engine was the various shipyards jobs and module building was not very common in those days. There were deviations from yard to yard.
Tore

[tore]

Simon.
 When looking at your recent engine drawing I discovered a tiny detail on the fuelsupply pipe to the HP pumps which, with you liking of details, might be worth while to incorporate. On U 995 KNM Kaura the pipe between cylinder 7 and 8, is a draincock marked red on the port engine and only a cock connection shown on the stb engine. See the very bad picture below.
Tore

[NZSnowman]

Starting Air Control Supply and Starting Manifold added.


Scale: 1 pixel = 2.35 mm

[tore]

Simon, one step further to perfection.
Tore

[tore]

Fig. 1. Side view of new Air Starting supply piping.


Fig. 2. Top view of new Air Starting supply piping.


Fig. 3. New Air Starting supply piping under the decking. The layout is correct but the some of the piping and the

[tore]

Starting handles.
I guess you are about to draw the starting handles at the maneuvering stand. They are the same for port and stb engines, so the startinghandles are placed towards port and fuelhandles towards stb on both engines, which means that the linkage seen on the inboard side of the maneuvering stands are different (startinglinkage visible on the stb- and fuellinkage on the port engine). Another detail, all the handles are like double, the second handle is a lockingdevice and has to be pressed in in order to move the levers. .
Tore

[SnakeDoc]

Tore, I know, that fuel oil tanks (internal and external) were water-compensated. Were there a problem of mixing fuel oil and water (near the border between the layers of water and fuel)? I mean, if there created some kind of an emulsion?


--
Thanks, regards
Maciek

[tore]

Maciek.
All the fueltanks were seawatercompensated except the settlingtank ( daytanks). There are several reason for that 1. What we call free surface effect has particularly a bad influence on a submarine with neutral buoyancy, and you want to avoid that by allways keeping as many tanks as possible  topped up. 2. As you consume fuel the submarines weight decreases and has to be compensated by increasing the ballast, eg. taking in seawater. The system is that you always have seawater under pressure lead to the bottom of the fueltank and have the fuellines outlet  on the top. The positive pressure under both surface and snorting is maintained by a header tank in the towercasing.
The only fueltanks which are not watercompensated are the two tanks above the engines, one act like a settling tank which means you fill it with fuel  and let the fuel settle and drain possible water while you are running the diesels from the other tank. We never had any emulsion with seawater and dieselfuel as you could have with lubeoil, but the latter did not have any water compensated tanks ( small tanks small surface effect)
Tore

[tore]

Maciek.
 As a follow up of my last post it might be a bit easier to look at the drawing below.
Tore 

[SnakeDoc]

Tore, thanks for answer. Could you mark the location of head tank in conning tower (if possible, using this drawings: http://uboatarchive.net/U-570GeneralPlan.htm)


--
Thanks, regards
Maciek

[tore]

Tore, thanks for answer. Could you mark the location of head tank in conning tower (if possible, using this drawings: http://uboatarchive.net/U-570GeneralPlan.htm)


--
Thanks, regards
Maciek

Maciek.
The head tank or may better buffertank is not a big tank,just big enough to keep a positive head in the system. It is fed from the coolingwater outlet at the exhaustsilencer, the location is about where I put the arrow on the drawing below.
Tore

[NZSnowman]

Tore, thanks for answer. Could you mark the location of head tank in conning tower (if possible, using this drawings: http://uboatarchive.net/U-570GeneralPlan.htm)


--
Thanks, regards
Maciek

Maciek.
The head tank or may better buffertank is not a big tank,just big enough to keep a positive head in the system. It is fed from the coolingwater outlet at the exhaustsilencer, the location is about where I put the arrow on the drawing below.
Tore

Tore, can you remember approximately the dimensions of the buffer tank? As this would be a great little detail to add to my main drawing.

[tore]

Simon right now I cannot say the volume, you know the idea was not a supply tank and the space available in that area was not great. As you know the tower came in various executions but the design was made for a minimum of towercasing like the 1940 -41 execution. We stripped the wintergarden and reconstructed the towercasing with a minimum of volume keeping all the airducts, vents and buffertanks as originally designed.
Tore

[NZSnowman]

Fig. 1. Side view of new Air Starting supply piping.


Fig. 2. Top view of new Air Starting supply piping.


Fig. 3. New Air Starting supply piping under the decking. The layout is correct but the some of the piping and the

[tore]

Simon.
I guess the most probable place for  the supply from the 205 kg/cm2 mainline would be starboard above the floorplating. Looking at your photo showing starboard enginefront I have tried to indicate my proposal. Usually the small pipes are the 205 kg/cm2 pipeline and the larger 30 kg/cm2 lines. The indicated 205/30 kg cm2 reducingvalve has a handwheel, that could be a combination of a shut off valve and reducingvalve deviating from the pipeline drawing by making one unit. it is placed relatively easy accessable which makes it probable this is the HP main supply/reducing valve.  The manometers hardly visible outboard starboard could be local manometers showing the supply/reducing pressure because the manometers shown at the drawing you would find up at the instrumentpanel above the maneuvering stand. Se my drawing below and remember it is a guesswork ( hopefully intelligent).
Tore

[tore]

Simon.
I`m a bit in doubt if the supply line from the compressor would be under the floorplating, I have a liking for outboard on starborad side.
Tore

[tore]

Simon.
Not all ideas are brilliant, I guess I have to revise a few details having given it a second thought.. I found that the HP air systemsketch and the starting air sketch are not in correspondence as they have different type of valves and only the startingair sketch have a direct line to the compressors. I thought the latter solution was a bit strange so I suggest to skip it and stick to the HP systemsketch. Further I have been able to see the details after the HP startingair supply valve and discovered the small airpipe and the filter after the valve so below is my revised proposal.
Tore

[NZSnowman]

Simon.
I guess the most probable place for  the supply from the 205 kg/cm2 mainline would be starboard above the floorplating. Looking at your photo showing starboard enginefront I have tried to indicate my proposal. Usually the small pipes are the 205 kg/cm2 pipeline and the larger 30 kg/cm2 lines. The indicated 205/30 kg cm2 reducingvalve has a handwheel, that could be a combination of a shut off valve and reducingvalve deviating from the pipeline drawing by making one unit. it is placed relatively easy accessable which makes it probable this is the HP main supply/reducing valve.  The manometers hardly visible outboard starboard could be local manometers showing the supply/reducing pressure because the manometers shown at the drawing you would find up at the instrumentpanel above the maneuvering stand. Se my drawing below and remember it is a guesswork ( hopefully intelligent).
Tore

Hi Tore

I been studying all my photo

[NZSnowman]

This is more confusing for me. Below is the port air bottle. I know that the red pipe is the inlet pipe (40 mm) to the Starting Manifold. The blue pipe (15 mm) is the drain line. But the line out of the bottle only looks 15 mm

[NZSnowman]

Tore, we know the HP bottle ends are the same. Could the German had the drain line at the lower bow end of the bottle (15 mm pipe) and the air outlet at the stem end (40 mm pipe)? This could be why we can not see the 40 mm pipe in the photo above?

[NZSnowman]

Tore, many updates to the side view.


Fig. 1. New updated drawing.


Fig. 2. old drawing.

[NZSnowman]

Tore, are the cover plates fixed by screws, bolts or rivets?

[tore]

Tore, we know the HP bottle ends are the same. Could the German had the drain line at the lower bow end of the bottle (15 mm pipe) and the air outlet at the stem end (40 mm pipe)? This could be why we can not see the 40 mm pipe in the photo above?

Simon.
I was home too late yesterday to look into this, but ready for action this morning. As you have noticed all the airvessels are tilting , this is because you want to collect the water at one end where you put the drain. I have look into the matter of outlet pipe a bit more before I have an answer and shall revert within short.
Tore

[SnakeDoc]

Tore, I was always wondering about Fuel oil venting, sounding and test piping :
http://uboatarchive.net/U-570Plate8.htm
http://uboatarchive.net/U-570Plate8A.htm
but I have never been able to figure it out entirely.
For instance, the following piping for inner fuel oil tank Treib

[tore]

Simon.
I guess we have to reconsider the whole thing. We have located the HP supply regulatingvalve, HP filter and the 205>30 kg/cm2 reductionvalve all placed on starboard side. Between these items are 20mm pipes. Out from the reductionvalve I have not been able to ascertain the pipedimension, but looking at the valvehousing I doubt if it is a 40 mm pipe out from this valve so I assume 20mm. We know that to and from the main startingvalve at the maneuvering stand the pipes are 40mm, thus the pipe from the airvessel should be 40mm.
The pipe at the forward end of the airvessel shown on your photo is definitely a full 20mm airpipe going upwards, hardly a drainpipe, the smaller pipe which can be seen could be a drain. I have not been able to locate any crossover. Unless you have any photos showing otherwise my proposal would be: The supply to the starting airvessels from the reduction valve on starboard side is 20mm, entering both  vessels at lowered forward end, which means that the crossover is a 20 mm pipe. The separate airsupply from the starting air vessel to each engine is from the aft end of the vessel (as you was asking) to the main startingvalve on the engine. It is no 40mm crossconnection.  Each engine takes its startingair from its "own" vessel by the 40mm pipe from the airvessel aft side, the 20mm pipe is only used for topping up (filling) the airvessels. The lay out is based on a direct reversible engine which has a large airconsumption (you have to restart every time you change direction of revolutions) thus the capacity of the airvessel should be for at least 10 starts before topping up.
Tore

[tore]

Simon.
Your update is excellent, pipedimensions better and even turning the coolingwater thermometers for  more convenient readings.
Tore

[tore]

Tore, are the cover plates fixed by screws, bolts or rivets?

Simon.
Hard to tell under all that paint,but I believe they were bolts with hexagon heads.
Tore

[tore]

Maciek.
Fueltank measuring.
You are particularly interrested in an easy description on sketch 3. On the posted sketch 3 below is red the partition between the green seawater and the lighter fuel on top. Remember the fueltank is always under positive pressure from the buffer/headertank. When you want to measure you equalize the pressure or fuel level in the testpipe by putting the cock in a position so the testpipe  gets an equal liquid level as the tank (red/yellow column in the pipe). When you turn the cock in measured drain position, the red/yellow liquidcolumn is sealed off and is forced by the positive head waterpressure into a inboard measuring canister. You shut off the drain when water is coming, how much water you get in the canister is irrelevant as the only liquid your measure is the fuel and that is accurately fixed. By a table relevant for that particular tank you can read of how much fuel is left in the tank.
Tore

[SnakeDoc]

Tore, many thanks!

and is forced by the positive head waterpressure into a inboard measuring canister. You shut off the drain when water is coming, how much water you get in the canister is irrelevant as the only liquid your measure is the fuel and that is accurately fixed

That's the part which I would never guess. Once again, thanks


--
Best regards
Maciek

[NZSnowman]

Simon.
I guess we have to reconsider the whole thing. We have located the HP supply regulatingvalve, HP filter and the 205>30 kg/cm2 reductionvalve all placed on starboard side. Between these items are 20mm pipes. Out from the reductionvalve I have not been able to ascertain the pipedimension, but looking at the valvehousing I doubt if it is a 40 mm pipe out from this valve so I assume 20mm. We know that to and from the main startingvalve at the maneuvering stand the pipes are 40mm, thus the pipe from the airvessel should be 40mm.
The pipe at the forward end of the airvessel shown on your photo is definitely a full 20mm airpipe going upwards, hardly a drainpipe, the smaller pipe which can be seen could be a drain. I have not been able to locate any crossover. Unless you have any photos showing otherwise my proposal would be: The supply to the starting airvessels from the reduction valve on starboard side is 20mm, entering both  vessels at lowered forward end, which means that the crossover is a 20 mm pipe. The separate airsupply from the starting air vessel to each engine is from the aft end of the vessel (as you was asking) to the main startingvalve on the engine. It is no 40mm crossconnection.  Each engine takes its startingair from its "own" vessel by the 40mm pipe from the airvessel aft side, the 20mm pipe is only used for topping up (filling) the airvessels. The lay out is based on a direct reversible engine which has a large airconsumption (you have to restart every time you change direction of revolutions) thus the capacity of the airvessel should be for at least 10 starts before topping up.
Tore

Tore, this sound great
 
I have no photo's of the

[tore]

Simon.
From an engineering point of view it would be unnecessary and more spacedemanding to use a crossover of 40mm as the crossover is only a filling line and not a consumption line. German engineering is optimal so I don`t see why they should choose  a pipesize double of what is needed. You have to find a very good picture/argument to convince me of a 40mm solution.
Tore

[NZSnowman]

While rechecking the piping this morning I also noted there is a different piping layout between the port and starboard engine, between the air bottles and the starting manifold.  On the port engine the pipe follow the contour of the engine, on the starboard side the same pipe run forward for about 300 mm and then follows the main air vent down.
 
I will update my drawing to show this also.

[tore]

Simon.
Yes, but watch out for the coolingwater returnpipe from the exhaustmanifold to the inlet of the engine attached coolingwater pumps in the same area, it is easy to get mixed up as they are of aproximately the same dimension..
Tore

[NZSnowman]

Simon.
Yes, but watch out for the coolingwater returnpipe from the exhaustmanifold to the inlet of the engine attached coolingwater pumps in the same area, it is easy to get mixed up as they are of aproximately the same dimension..
Tore

Fig. 1. Port Side


Fig. 2. Starboard.
(source: U-995 DVD http://www.uboataces.com/u995.shtml)

[tore]

Simon.
Interesting photos. On stb side I guess you have noticed that on the reducing valve the outgoing pipe (30 kg/cm2) is  a bit  larger diameter than the ingoing (205 Kg/cm2). On the port side it is an interesting detail on the airinduction system which we can use when you shall go into details with regard to the supercharger system. Very good!
Tore

[NZSnowman]

Red  = 40 mm
Blue - 30 mm
Green = 10 mm



I found the cross over  You can just see it at the bottom of the photo.
(source: U-995 DVD http://www.uboataces.com/u995.shtml)

[tore]

Simon.
Well done!
Tore

[NZSnowman]

Simon.
Yes, but watch out for the coolingwater returnpipe from the exhaustmanifold to the inlet of the engine attached coolingwater pumps in the same area, it is easy to get mixed up as they are of aproximately the same dimension..
Tore

Fig. 1. Port Side


Fig. 2. Starboard.
(source: U-995 DVD http://www.uboataces.com/u995.shtml)

Here a better view of the port pipe, you can easily see how the pipe contour the engine and gone between the engine and the exhaust.

[NZSnowman]

Tore, what time zone are you in, is it GTM +1:00?

If so, being so far north, it must be getting dark very early currectly about 5:00pm??

[NZSnowman]

Tore, found a small error in the placement of the Air Starting Rocker Arm. It needed to move the end of the Rocker Arm, closer toward the fuel pump.


Fig. 1. New drawing.


Fig. 2. Old drawing.

[tore]

Simon.
New enginetop drawing.
Seems to be fine as usual, however I just noticed you give the exhaustvalve ample lubrication via two lines whereas the inletvalve has none. As far as I can see both valves have lubrication but at different inlet points, exhaust from the side and inlet from the top, see picture.
Tore

[tore]

Simon.
We are in the central Europe zone, GMT +1 hour. Right now it gets dark at 1600 and daybreak at 0900 in my area, but further north about half of the country don`t get sun at all starting at the North Cape in a few days.
Tore

[tore]

Simon .
Your new pictures showing the forward front and outboard side of the engine are great and useful for coming scrutinizing.
Tore

[SnakeDoc]

Hi Gents


I was able to find following information: the diameter of HP air piping leading to starting air flasks: internal - 36,5 mm, external - 44,5 mm.


--
Regards
Maciek

[tore]

Simon. On a few photos from the U 995 engineroom, outboard gratings are fitted between the engines and hullside. I cannot remember we ever had them and I don`t see the purpose for it . I guess they are installed to prevent visitors from crawling into that cramped space and suggest you skip it on your drawings.
Tore

[tore]

Hi Maciek!
I guess the dimension fit pretty much in with the pipes in Simon's drawing.
Tore

[NZSnowman]

Hi Gents


I was able to find following information: the diameter of HP air piping leading to starting air flasks: internal - 36,5 mm, external - 44,5 mm.


--
Regards
Maciek

Hi Maciek!
I guess the dimension fit pretty much in with the pipes in Simon's drawing.
Tore

Yes, it

[NZSnowman]

Tore, the line between the air compressor and the cross-over, what diameter do you think it is?

[tore]

Simon.
I am not sure  it is a line if you cannot see it on a photo. If you are able to confirm it visually then  I would guess the same as the 30 kg/cm2 pipe after the reducingvalve see picture below, it seems to be at least 20 mm. But this is one of the reasons I believe I`m in doubt of this pipe why should it be a direct 205 kg/cm2 connection directly without a reducingvalve to a 30 kg/cm2 system? That is quite a hazard, more over this pipe is not shown on the HP air diagram. The only reason I can think of is that it could be an emergency connection the other way eg. the startingair vessel used to supply air to the HPsystem in that case it would have been easier and safer to do it via the controlroom.
Tore

[tore]

Simon. I just checked the starting air system for the MAN engine. The direct line from the compressor shown on the diagram for the GW engine is not drawn in I guess my assumption is correct it is not such a connection. It would be completely  crazy. See the MAN system below, remember the MAN has a two stage reduction.
Tore

[tore]

Simon.
I have checked the various HP air system sketches  in my possession and except for the simple GW starting airsketch non of the others shows any direct connection between the compressors and the starting air crossoverline. As you see on the sketch below it is a 2nd connection from the compressors which is connected, (as I presumed) directly to the HP manifold in the controlroom and no connection to the crossover or the air starting system as the main HP line via a reducingvalve.
Tore

[SnakeDoc]

Hi


Just a thought, maybe the "starting air diagram for GW" (with additional, direct connection to the compressor) is the version for early boats (U93-U97) made by Krupp Yard, equipped with two electric compressors (similar issue as  Cooling-water system diagrams). The later boats (with GW and MAN engines) had one Junkers compressor (Luft Verdichter 1) and one electric driven compressor (Luft Verdichter 2). And in these boats, the direct connection was removed?


--
Regards
Maciek

[tore]

Maciek-
An interesting idea, in that case the line would have to have a reducingvalve 205kg/cm2>30kg/cm2. Theoretically you could take a bleed off from the 2nd stage on the E-compressor ( appr. 30 kg/cm2), however on a freepiston compressor (Junker) I guess it would upset the balance which makes it impossible. If the 2nd connection to the control room is from the original design, including U92-97, which I believe, then I still fail to see why you should have a 3rd connection and not just a bleed off from the 2nd. pipe directly or rather via a reducingvalve in the engineroom to the crossover.
Tore

[SnakeDoc]

Or - other idea (inspired by Design Study of Former German Submarine  - Type IXC: "The starting air system supplies air for starting the main engines and the diesel air compressor. " http://uboatarchive.net/DesignStudiesTypeIXC.htm ) : this line exists only on boats with Junkers compressors (all type VIIC except U92-U97), because compressed air was used to start Junkers compressor (though I have always thought, that Ju-Verdichter was started manually).
Gents, in above mentioned report try use search for string "starting air" - maybe it tells something more...


--
Regards
Maciek

[SnakeDoc]

compressed air was used to start Junkers compressor (though I have always thought, that Ju-Verdichter was started manually).

For starting up, compressed air is directed on the pistons brought into the outside position.

page 49, http://uboatarchive.net/U-570BritishReport.htm


--
Regards
Maciek

[tore]

Maciek.
Brilliant! That`s it, we were fooled by  a sketch connection directly to the compressor assuming it was a supplyline from the compressor, forgetting the startingair to the Junker compressor which of course I shouldn't  have forgotten. Why was it different on the MAN system?  If you look at the system for the MAN engines, the crossover on the  system has a pressure of 75 kg/cm2 as the 2nd stage reduction of 75>30 kg/cm2 is on each separate engine thus you cannot use the crossover for starting air supply on the MAN system.On the MAN system the startingair for the Junker is taken from the ordinary HP supplyline of 205 kg/cm2 in the aft torpedoroom where it is connected to the Junker starting valve via an ordinary reductionvalve 205>30 kg/cm2.
 Simon, to make it simple: on the GW installations like U1308 and U 995 it is indeed a connection, presumably at least 20mm, from the crossover to the  startingvalve of the opposed piston Junker dieselcompressor which was installed on all VIICs after U 97. It is not a supply from the compressors. Thanks to Maciek.
Tore

[tore]

Simon-
Junker compressor startingsystem.
Further to my earlier post, the starting airpipe connection from the crossover to the Junker is via a compressor starting airvessel underneath the Junker. From this vessel the pipe goes to the starting valve at the center of the compressor as indicated on the bad photo below. I guess the size of the pipe from the crossover should not exceed 20 mm, rather smaller, as it is only a topping up line. The consumption for starting the compressor is taken from the starting airvessel. May be you are able to guess the dimension of the pipe by looking at the photo or better you shall find a good quality picture a U historia or may be from one of your exellent resources..
Tore

[NZSnowman]

Air Starting System


Fig. 1. Port Side.


Fig. 2. Starboard Side.


Fig. 3. Port and starboard Engine.

[tore]

Simon.
 It`s always a pleasure to see your drawings. As usual I have a few minor remarks. At the end of the fuelrack both stb. and port forward are endsprings enclosed in a steelsleeve, see picture.
Tore

[tore]

Simon.
Exhaust and inlet valve lubrication.
 I think it is a confusion here. In the British report from the inspection of the U 570 is mentioned that the cylinders are lubricated by luboilpipes inboard and outboard from the Gruetzner lubricators, further is mentioned that the inlet-and the exhaustvalves are lubricated by a camshaftdriven "mechanical pump".
Separate luboil connection to the cylinder liners is a very oldfashioned way of lubricating cylinderliners, in Germany during the years 1930-40 they were usually lubricated by the oil in the crankcase which is distributed and controlled in the cylinder by the pistonring arrangement. I cannot remember we had such a separate lubrication. I have not been able to locate any luboilpipes to the cylinderliners nor a "mechanical camshaftdriven luboilpump" which should take care of the valvelubrication except the Gruetzner lubricators having 12 pipeoutlets on each engine. In a way it is driven off the camshaft by a rod from the exhaust rockerarm on cyl 1. So if not somebody can explain and confirm the report of U 570 I`m inclined to skip the cylinder lubrication and let the Gruetzner take care of the valvestem lubrication.
Tore

[tore]

Simon.
Airstarting system.
This just the way it is, well done I guess it is an extra  small pipe from the forward end of the starting airvessel probably going  up to the pressuregauge.
Tore

[tore]

To all friends in US happy Thanksgiving!  to Simon good morning and  friends in Europe good night, I think it was an interesting day and I`m hitting the sack.
Tore

[TopherVIIC]

Thanks Tore from the U.S. ! I am thankful that you are able to give us so much new information and help us with our studies!
Christopher

[NZSnowman]

Gruetzner lubricator

[NZSnowman]

Hi Tore/Maciek

On Plate 10:  Fuel oil compensating system (circulating water under pressure), the handle for valve 'B' are located within the engine room?

http://www.uboatarchive.net/U-570Plate10.htm

[tore]

Simon.
Your drawings are getting more and more details. Knowing your likings for details, have a look at my bad picture below. The knife filters have usually a wheel or a handle at the top which is connected to a "brush" inside the filter cleaning the filterelement by turning the handle. I believe on the picture below it is a T-handle. I don`t fully understand the two smaller pipes coming from the top.
Tore

[tore]

Simon.
Fueloil compensating valves fuel oil saddle tanks.
The upper drawing you are showing is the system outside the pressurehull and I don`t believe the valves are operated from inside the pressurehull. The fuel/ballast saddletank 2 and 4 starboard and port are just made of light steel sheets and do not withstand any large pressure. They are equipped both as full fueloil bunkertanks and  full ballast tanks with all the connections required. The encircled valves have two positions either in direct connection with the head/buffertank in the tower or in contact with the sea via a small compensatingbox in the bottom of the tank. As fueltank the first position shall be used to ensure the compensating head is allways positive but not exceeding the differential pressure (the hight difference between the headtank in the tower and the fueltank). Eg. irrelevant of the ambient pressure regardless the diving depth. 
Tore

[tore]

Simon-
Side view engine drawing.
I just had another look on the fuelsupply/drainpipes realizing it is not yet finished but nevertheless I put forward a few remarks. It looks to me that the drain from the knife filter driptray is hooked up to the suctionside of the engine driven fuel supplypump instead of a funnel/collectingtank and what I presume is the supplyline to the knife filter seems to go up and not horizontally to the filter. See my picture.
Tore

[NZSnowman]

Hi Tore

I am trying to update my fuel lines now (the copper colour piping).

• I noted that I have miss the outlet pipe from the fuel filter.
• I seen to also missing the inlet piping to the fuel filter. Does it enter into the back of the filter? Where does the fuel come from?

[tore]

Simon.
It is a bit difficult to explain without the supply pipe from the daytank and the next cock so I introduce them as well. Fuel comes from the overhead daytank to cock 1 violet pipe. normally it goes to the fuel supplypump suction pressure boosted an goes from the pump (red) to a cock directing the fuel to the dual filter comes from the filter to the next cock from there to the knifefilter and the HP fuelpumps (still red). The cocks makes it possible to shut off either pump or the dualfilter or both. then you can operate for emergency the engine by the gravity supply of the overheadtank and filter the fuel by the knife filter. The yellow drain from the knifefilter is not connected to the system.
Tore

[tore]

Simon the above picture was lousy I am trying a better quality below.
Tore

[tore]

Simon .
Just another try to see if I can produce a better quality picture of the system.
Tore

[NZSnowman]

Thanks Tore

Don't do any drawing today, so will have a look tomorrow.

Off to bed now 

[NZSnowman]

The yellow drain from the knifefilter is not connected to the system.

Hi Tore

The drain line is this drawing may look like its connected to this system, but I have the fuel system on a different layer. I will add this layer to the drawing and post pictures for you.

Simon

[NZSnowman]

New fuel oil filter and now including inlet piping

[tore]

Very good Simon, it is quite a visible part of the engine so I guess it is nice to have it correct. I have not been able to establish the in and out pipeconnections on the knife filter. Some of them have connection in the bottom, others on the top. I would guess bottom towards the engine.
Tore

[NZSnowman]

Very good Simon, it is quite a visible part of the engine so I guess it is nice to have it correct. I have not been able to establish the in and out pipeconnections on the knife filter. Some of them have connection in the bottom, others on the top. I would guess bottom towards the engine.
Tore

I was just about to ask you this question and was writing it up but you must be faster than me I will feed them into the back of the filter.

I will post new drawings is a few day, as I am away tomorrow.

[NZSnowman]

Tore, here the fuel oil layer added, should keep you busy tomorrow

[NZSnowman]

Tore/or anyone, not sure if you know this, but the forum will resize my drawings to 800 px, if you left-hand click the drawings it will rescale the drawing to it original size.

[tore]

Very good Simon I`m off to bed now, may be you put the T handle on the filter by tommorrow morning.
Tore

[tore]

Simon.
You are right the fuel layer shall keep me busy today. I`ll start at the top. The tank you have drawn up under the pressurehull is the hearth or rather the stomach of the whole system. The tank is split in two halves along a mid shipline and function like a purifyer, clarifyer and a head/supplytank to the engines. It is fed by white pipeline  on the picture below from the fuel pressure watercompensated bunkertank system to the aft end of the headtank via cocks.
 During normal service you take fuel for both engines from one of the tanks, while the other is filled from the bunkertanks and then let the fuel settle so the water and impurities collects in the bottom of the tank, that takes a while but  it is ready for use when the other tank is nearly empty. Below is a drawing where I have tried to show the details of the supplysystem. Amongst the mess of arrows I have indicated a valve and line in yellow, leading fuel to the Junker compressor which we shouldn't`t forget this time. The system sketch is showing as usual the MAN system with fuel supplypump driven off from the camshaft aft end, as mentioned before remember on the GW it is driven from the crankshafts  forward end.
 With so many arrows  I think I better split this up and go into details of the supply system from the daytank in a separate post.
 A small detail to mention, the tank is fitted with 3 brackets on each side to the upper frames of the pressurehull, the aft fitting is  fixed by wire to welded on eyes to the plating as the tank end does not quite meet the aft frame. The light underneath the tank seems to be on the small side , the diameter is about a 5th or 6th of the length of the tank.
Tore

[tore]

Simon
The fuelsupply system from the daytank.
The fuel from the overhead daytank goes from the selected tank via a cock which, when open for delivery (red) allows the other tank to open for supply (green). The red supply lines to both engines goes along the engines  as a black pipe ( it was never black in my time) to the selection cock on the forward engine side, the system from here has been explained previously. On the forward side of the daytank are sight glasses for each tank as well as drainpipes with cocks and ventpipes all ending up in a collecting tank. These pipes are all fitted on the port engine.

[SnakeDoc]

Hi Simon

On Plate 10:  Fuel oil compensating system (circulating water under pressure), the handle for valve 'B' are located within the engine room?

In my opinion, there was no need to make this valves operational from inside of the pressure hull.
Moreover, in the section Openings in the pressure hull of http://uboatarchive.net/Manual.htm, there
is no mention about shafts for these valves (either in diesel engine room as well as in Control room).


--
Regards
Maciek

[tore]

Hi Simon

On Plate 10:  Fuel oil compensating system (circulating water under pressure), the handle for valve 'B' are located within the engine room?

In my opinion, there was no need to make this valves operational from inside of the pressure hull.
Moreover, in the section Openings in the pressure hull of http://uboatarchive.net/Manual.htm, there
is no mention about shafts for these valves (either in diesel engine room as well as in Control room).


--
Regards
Maciek

Yes I agree Maciek, see my answer nov. 23rd.
Tore

[tore]

Simon
Fuel supply system from day tank.
Checking my post earlier today on this subject I realize the relevant picture was not posted, I guess it is becoming too many pictures. Anyhow below is the picture which I hope gives a better understanding of the text.
Tore

[tore]

Simon.
Fuel drain.
The main fuel drain on the engine goes along the engine just about where the cylindercovers meets the cylinder block, it collect the spill from each cylindercover via funnels and leads to the forward of the engines joins the drain (yellow) from the knifefilter before it drain into the fuel draintank. It is no T piece where the fuel filter enters the maindrain, just a welded branch with threads for the connection.
Tore

[tore]

Simon.
Crankcase doors.
Now we are really going into details, but I happened to notice some small discrepancies on your bedplate/ crankcasedoors. As you see on the picture below, the stiffening knees between the crankcasedoors are ending a bit higher up between the doors and the narrow end cover up forward is protruding further down than the ordinary crankcase doors. The narrow frontcover is just a plate. Crayzy details hardly noticed by anybody but mee. 
Tore

[tore]

Simon .
Drain box.
Realizing your latest drawing  may not yet be completed I shall nevertheless mention this small detail.   The drainbox up forward I believe it is a bit larger almost the full height of the camshaftcover, see picture below.You said it before, you love details.  
Tore 

[tore]

Simon.
Crankcase doors and floorplating.
You have probably not yet fitted the floorplating in the engine room, prior to that, be aware of a detail. It is a fairly big step down to the floorplating between the engines, the reason for that is you want to have access to the crankcase through the crankcasedoors without having to dismantle the floor. By lowering the floorplates you are making it difficult to have access to the engine top which require frequent inspections and maintenance. A stepplate is hinged all along the engine  right below the camshaft covers. On the U 995 it is folded down, howewer when needed you fold it up and behind the plates are folded in brackets which you fold out to get support for the plates. See picture below. You can get further detail on the U historia.
Tore

[NZSnowman]

Hi Tore

Just letting you know that were will be no new drawings for the next few days. I am taking a break from drawing and catch-up on some other work.

Simon.
Fueloil compensating valves fuel oil saddle tanks.
The upper drawing you are showing is the system outside the pressurehull and I don`t believe the valves are operated from inside the pressurehull. The fuel/ballast saddletank 2 and 4 starboard and port are just made of light steel sheets and do not withstand any large pressure. They are equipped both as full fueloil bunkertanks and  full ballast tanks with all the connections required. The encircled valves have two positions either in direct connection with the head/buffertank in the tower or in contact with the sea via a small compensatingbox in the bottom of the tank. As fueltank the first position shall be used to ensure the compensating head is allways positive but not exceeding the differential pressure (the hight difference between the headtank in the tower and the fueltank). Eg. irrelevant of the ambient pressure regardless the diving depth. 
Tore

Tore, that dimension do you think this pipe would be? I was thinking about 75 mm.

[tore]

Hi Tore

Just letting you know that were will be no new drawings for the next few days. I am taking a break from drawing and catch-up on some other work.

Simon.

Fueloil compensating valves fuel oil saddle tanks.
The upper drawing you are showing is the system outside the pressurehull and I don`t believe the valves are operated from inside the pressurehull. The fuel/ballast saddletank 2 and 4 starboard and port are just made of light steel sheets and do not withstand any large pressure. They are equipped both as full fueloil bunkertanks and  full ballast tanks with all the connections required. The encircled valves have two positions either in direct connection with the head/buffertank in the tower or in contact with the sea via a small compensatingbox in the bottom of the tank. As fueltank the first position shall be used to ensure the compensating head is allways positive but not exceeding the differential pressure (the height difference between the headtank in the tower and the fueltank). Eg. irrelevant of the ambient pressure regardless the diving depth. 
Tore

Tore, that dimension do you think this pipe would be? I was thinking about 75 mm.

Simon.
To me 75 mm diameter seems to be on the large side. I don`t think it would be any bigger than the fuelpipe from the tanks entering the engineroom as seen on the picture below previously displaid.
Tore

[tore]

Simon
It sounds strange but I guess there are other things going on in the world but VIICs. Looking forward to seeing your upgraded drawings in due time!


Tore

[SnakeDoc]

Hi Tore, Simon


Take a look into quite old thread here:
http://models.rokket.biz/index.php?topic=106.msg9557#msg9557


--
Regards
Maciek

[tore]

Hi Tore, Simon


Take a look into quite old thread here:
http://models.rokket.biz/index.php?topic=106.msg9557#msg9557
 Hi Maciek.
Interesting thread. I agree to your identification of the Kingstons. However the biggest pipe/duct is to my opinion too large for being a soundingpipe, in fact too large for any liquid. My suggestion would be it is possibly the main ventpipe joining the stb ballasttank 2 to the commom  main ventvalve operated from the control room, it is only in use when ballast/fueltanks 2 port and stb are  used as ballast tanks. The pipe is indeed pointing downwards, but the appearant heavy corrosion  could have removed the support, anyhow I  don`t have any other suggestion right now.
 As the seawater compensating pipe is only supplying the same volume of liquid as the fuelpipe take out of the tank, I don`t see any reason  that the compensating pipe should have to be of an other dimension than the fuelpipe shown on my picture above.
Tore

[SnakeDoc]

Hi Tore

However the biggest pipe/duct is to my opinion too large for being a soundingpipe, in fact too large for any liquid. My suggestion would be it is possibly the main ventpipe joining the stb ballasttank 2 to the commom  main ventvalve operated from the control room, it is only in use when ballast/fueltanks 2 port and stb are  used as ballast tanks. The pipe is indeed pointing downwards, but the appearant heavy corrosion  could have removed the support, anyhow I  don`t have any other suggestion right now.

Isn't this pipe too thin for vent duct? On this plate:
http://uboatarchive.net/U-570Plate28.htm
is given cross-section area: 3,167 m². Based on this, I would estimate the diameter for about 1 m.
Also, here is Simon's drawing showing this arrangement:
http://models.rokket.biz/index.php?topic=106.msg10098#msg10098
Comparing to the wreck's photo, it seems that vent ducts are a little bit larger.

As the seawater compensating pipe is only supplying the same volume of liquid as the fuelpipe take out of the tank, I don`t see any reason  that the compensating pipe should have to be of an other dimension than the fuelpipe shown on my picture above.

Well, that's the point.


--
Regards
Maciek

[tore]

Hi Maciek.
The VIICs are well known to have a quick divingtime and have a remarkable Kingston flood openings, but having openings in excess of 3 square meters in a pipe under the casing, I would believe, is too much. It would require a ventdiameter of nearly 2 meters almost the size of the conningtower across. I guess the crosssection area described in  the diagram refer to the 4 Kingston valves eg. floodarea of seawater into the bottom of the saddletank . That would be approximately  4x 0,8 square meters which, looking at the 4 square Kingston openings, seems to be correct. Down below I have posted  sketches showing the various components relation to the diameter of the pressurehull 4,7 meter. The distance between the frames is app. 0,5 m .
In the area of this ventpipe  the max. height between the casing deck and pressurehull is, I guess, 0,70 m. If you compare the vent pipepipe drawing for fwd. ballastanks port and stb. plate 28 with the drawn frame hight app 15 cm, you would end up with a pipediameter of approximately 250 max 300mm, easily fitted under the casing deck and probably not too far away from the biggest pipe shown on the wreck. The  bend on the end of the pipe could be where the pipe would have entered the saddletank.
Tore

[tore]

Hi Maciek.
Further to my latest post I`m showing below a detail of my ventpipe theory. The emergency shut off for each individual ballasttank is showing the pipedimension, as you see the pipe is of a moderate size.
Tore

[NZSnowman]

Hi Tore

Dani, over at U-Historia as updated his 'Fuel' page.

http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=es&tl=en&u=http%3A%2F%2Fwww.u-historia.com%2Fuhistoria%2Ftecnico%2Fvisitaguiada%2Fvisita.htm

[tore]

Simon this is exellent, I`ll have a closer look at it later today.
Tore

[tore]

Simon.
Fuelsystem
The thread shows some interesting new drawings and photos. The English translation is not easy to understand as some strange words  and sentences are used. I guess the translator do not fully understand the system which is a must for a correct technical English text. I stick to my short and incomplete description of Nov. 25Th. and if somebody would have a question based on the new pictures and drawings I shall be happy to answere if I can.
Tore

[SnakeDoc]

Hi Tore,


thanks for drawings illustrating scale problem. Location of cross-section area (near vents drawing) confused me totally and I forgot about estimating sizes and diameters.


I have got some kind of operational question: as far as I know, the primary station for helmsman was located in conning tower, and the second one was in control room (I think there was also possibility to move control panel from conning tower to the bridge, when performing docking maneuvers (or so on).  When RNoN operated KMN Kaura, which station was used typically (conning tower or control room)? Did it depend on cruise condition (submerged/surfaced)? Also, if helmsman was in conning tower, was there enough space for operating (riding around) fixed-eye-level periscope?


--
Thanks, regards
Maciek

[tore]

Hi Maciek.
Submerged we usually had the helmsman placed in the controlroom , together with the hydroplaneoperators. The reason for that is the officer on watch was  responsible for both functions and you want to be in physical contact with all three. During surface patrol in peacetime and fair weather it could happen the helmsman was on the bridge as well as during manoeuvring during docking, otherwise in the controlroom. Diving station the helmsman was in the controlroom.  During attack some CO wanted to have the helmsman in the conningtower but as far as I remember he was mostly in the controlroom.
Surfaced in rough weather ( when the bridge was washed over) we  operated the sub from the controlroom using the navigation periscope and shut the top hatch.
You might find a difference between the German way of operation as they used the engineering officer as diving/trimming officer whereas we and the RN used a navigator, No1, for this function. Our engineering officer was used during attack for calculating distances and stationed in the controlroom, No1 was in charge of the helmsman and hydroplanes/trimming and stationed in the controlroom as well.
Tore

[tore]

Maciek.
Helmsman space in conningtower.
I see I forgot to comment on the helmsmans space in the conningtower. I don`t think it was very spacey,but it didn`t obstruct the turning of the attack periscope. If you look at the sketch below you see the distance between the periscope and conningtower pressureside turned 180 degrees leaving "plenty" of space for the helmsman. Note the the conningtower hatch is placed off center midship. The helmsman in heavy winter clothings shows the space.
Tore

[SnakeDoc]

Tore, thanks for your comments on helmsman stations and control room parties duties.
Well, indeed, from drawings it seems, that there is enough space in conning tower for
helmsman and periscope operator. I'm not sure, but wasn't there a third person - TDC operator?


--
Regards
Maciek

[tore]

Hi Maciek
I guess it could be 3 persons in the conningtower, but then it would be cramped. We usually  only had the CO and sometimes a TDC operator in the tower during attack. As I said the helmsman was usually in the controlroom as NO1 was in charge of both the trimming, hydroplanes and navigation (helmsman).
Tore

[NZSnowman]

In the area of this ventpipe  the max. height between the casing deck and pressurehull is, I guess, 0,70 m. If you compare the vent pipepipe drawing for fwd. ballastanks port and stb. plate 28 with the drawn frame hight app 15 cm, you would end up with a pipediameter of approximately 250 max 300mm, easily fitted under the casing deck and probably not too far away from the biggest pipe shown on the wreck.

I just checked my drawing, I went for 275 mm 

[NZSnowman]

Hi Tore

Just letting you know that were will be no new drawings for the next few days. I am taking a break from drawing and catch-up on some other work.

Simon.

Fueloil compensating valves fuel oil saddle tanks.
The upper drawing you are showing is the system outside the pressurehull and I don`t believe the valves are operated from inside the pressurehull. The fuel/ballast saddletank 2 and 4 starboard and port are just made of light steel sheets and do not withstand any large pressure. They are equipped both as full fueloil bunkertanks and  full ballast tanks with all the connections required. The encircled valves have two positions either in direct connection with the head/buffertank in the tower or in contact with the sea via a small compensatingbox in the bottom of the tank. As fueltank the first position shall be used to ensure the compensating head is allways positive but not exceeding the differential pressure (the height difference between the headtank in the tower and the fueltank). Eg. irrelevant of the ambient pressure regardless the diving depth. 
Tore

Tore, that dimension do you think this pipe would be? I was thinking about 75 mm.

Simon.
To me 75 mm diameter seems to be on the large side. I don`t think it would be any bigger than the fuelpipe from the tanks entering the engineroom as seen on the picture below previously displaid.
Tore

I just checked dive video of U-352 and U-1021, and I found no evidence of this pipe. I think after 60 years at the bottom of the sea all evidence is gone

[tore]

Simon.
Ventpipediameter.
I guess your choice of diameter is pretty much correct.
Tore

[tore]

Simon
Seawater compensating pipes.

Hi Tore

Just letting you know that were will be no new drawings for the next few days. I am taking a break from drawing and catch-up on some other work.

Simon.

Fueloil compensating valves fuel oil saddle tanks.
The upper drawing you are showing is the system outside the pressurehull and I don`t believe the valves are operated from inside the pressurehull. The fuel/ballast saddletank 2 and 4 starboard and port are just made of light steel sheets and do not withstand any large pressure. They are equipped both as full fueloil bunkertanks and  full ballast tanks with all the connections required. The encircled valves have two positions either in direct connection with the head/buffertank in the tower or in contact with the sea via a small compensatingbox in the bottom of the tank. As fueltank the first position shall be used to ensure the compensating head is allways positive but not exceeding the differential pressure (the height difference between the headtank in the tower and the fueltank). Eg. irrelevant of the ambient pressure regardless the diving depth. 
Tore

Tore, that dimension do you think this pipe would be? I was thinking about 75 mm.

Simon.
To me 75 mm diameter seems to be on the large side. I don`t think it would be any bigger than the fuelpipe from the tanks entering the engineroom as seen on the picture below previously displaid.
Tore

I just checked dive video of U-352 and U-1021, and I found no evidence of this pipe. I think after 60 years at the bottom of the sea all evidence is gone

Simon.
60 years at the bottom of the sea takes its toll I can assure you, it`s 59 years since I came on board the U 995 and quite a bit has changed both to me and the U 995 even at the surface.
I have studied the diameter of the pipe once more and reconsidered my guesswork.  I believe your estimate of 75mm is not too far away, may be a fraction smaller but I should think you could go for it.
Tore

[SnakeDoc]

Hi Gents


Few days ago, on 1st December, it has been 60 years ago, when U995 entered into the service as KNM Kaura.


--
Regards
Maciek

[tore]

Maciek
You are absolutely right, unbelievable it is 60 years since she was commissioned as KNM Kaura, but the date was December 6Th 1952. I embarked May 1953. She was our first and only VIIC/41 the two others were VIIC U 926 KNM Kya and VIIC U 1202 KNM Kinn.
Tore

[NZSnowman]

Fuel oil compensating system

Tore,

• How often would you need to open/close the

[NZSnowman]

Simon
Seawater compensating pipes.

Hi Tore

Just letting you know that were will be no new drawings for the next few days. I am taking a break from drawing and catch-up on some other work.

Simon.

Fueloil compensating valves fuel oil saddle tanks.
The upper drawing you are showing is the system outside the pressurehull and I don`t believe the valves are operated from inside the pressurehull. The fuel/ballast saddletank 2 and 4 starboard and port are just made of light steel sheets and do not withstand any large pressure. They are equipped both as full fueloil bunkertanks and  full ballast tanks with all the connections required. The encircled valves have two positions either in direct connection with the head/buffertank in the tower or in contact with the sea via a small compensatingbox in the bottom of the tank. As fueltank the first position shall be used to ensure the compensating head is allways positive but not exceeding the differential pressure (the height difference between the headtank in the tower and the fueltank). Eg. irrelevant of the ambient pressure regardless the diving depth. 
Tore

Tore, that dimension do you think this pipe would be? I was thinking about 75 mm.

Simon.
To me 75 mm diameter seems to be on the large side. I don`t think it would be any bigger than the fuelpipe from the tanks entering the engineroom as seen on the picture below previously displaid.
Tore

I just checked dive video of U-352 and U-1021, and I found no evidence of this pipe. I think after 60 years at the bottom of the sea all evidence is gone

Simon.
60 years at the bottom of the sea takes its toll I can assure you, it`s 59 years since I came on board the U 995 and quite a bit has changed both to me and the U 995 even at the surface.
I have studied the diameter of the pipe once more and reconsidered my guesswork.  I believe your estimate of 75mm is not too far away, may be a fraction smaller but I should think you could go for it.
Tore

I have decided to go for 60 mm.

[tore]

Simon
I guess that`s not far from the correct dimension.
Tore

[tore]

Simon
Fuel compensating saddle ballasttanks
The valve b is a valve only in use when you select the mode you want to use the saddletanks,as fuel tanks or ballasttanks. It is a double seated valve with only two positions  either in direct contact with the head tank in the conningtower when the saddletank is used as fueltank or in direct contact with the sea when the saddletank is used as ballasttank. I believe it is controlled from outside the pressurehull under the casingdeck as it is not often used. I think it is a hatch in the deck for access.
Tore

[NZSnowman]

Simon
Fuel compensating saddle ballasttanks
The valve b is a valve only in use when you select the mode you want to use the saddletanks,as fuel tanks or ballasttanks. It is a double seated valve with only two positions  either in direct contact with the head tank in the conningtower when the saddletank is used as fueltank or in direct contact with the sea when the saddletank is used as ballasttank. I believe it is controlled from outside the pressurehull under the casingdeck as it is not often used. I think it is a hatch in the deck for access.
Tore

Thanks Tore.

I have checked all my photo's and checked dive videos and found no evidence of these pipes. So this morning I started checking deck hatches and I think I can location the positions they enter the saddle tanks using the hatches. I will use this as my glide for the drawing.

Do you think the open end to the sea would have a pipe screen over the end to stop sea weeds etc entering the system?

[tore]

Simon
Sea connection for compensatingpipe.
I don`t believe there is much of a screen. This connection is not for transport of any seawater (throughflow) it is merely a seapressure equalizer connection. The Kingstons take care of the filling of the tank. I`ll see if I can figure out something better tommorrow.
Tore

[NZSnowman]

Simon
Sea connection for compensatingpipe.
I don`t believe there is much of a screen. This connection is not for transport of any seawater (throughflow) it is merely a seapressure equalizer connection. The Kingstons take care of the filling of the tank. I`ll see if I can figure out something better tommorrow.
Tore

Thanks, Tore.

I imagine if the opening is only for equalizing this open could be a lot small than the 60 mm pipe.

[tore]

Simon.
Saddle fuel/ballasttanks
I have not been able to find any drawing or picture of this arrangement. I have looked for a seawater connection but there is non. My conclusion would be, when used as ballasttanks the Kingstons are open and the tank is in direct contact with the sea. Thus when the compensatingpipe is shut to the compensatingtank
( headtank) the pipe is in contact with the seawater via the Kingstons.
Tore

[NZSnowman]

Simon
Fuel compensating saddle ballasttanks
The valve b is a valve only in use when you select the mode you want to use the saddletanks,as fuel tanks or ballasttanks. It is a double seated valve with only two positions  either in direct contact with the head tank in the conningtower when the saddletank is used as fueltank or in direct contact with the sea when the saddletank is used as ballasttank. I believe it is controlled from outside the pressurehull under the casingdeck as it is not often used. I think it is a hatch in the deck for access.
Tore

Thanks Tore.

I have checked all my photo's and checked dive videos and found no evidence of these pipes. So this morning I started checking deck hatches and I think I can location the positions they enter the saddle tanks using the hatches. I will use this as my glide for the drawing.

Do you think the open end to the sea would have a pipe screen over the end to stop sea weeds etc entering the system?

I think I may have an explanation why I can not found any evidence of these pipes. I previous imagine those pipes would run just above the pressure hull, but now I believe there is not enough room, so the Germans run those pipes just under the wooden deck. As both the decking of U-352 and U-1021 are gone, this is why I can not found these pipes in the dive videos.

[tore]

Simon.
That may be.  I think I have seen a drawing of the compensating box in the bottom of the saddletank. See below,  I made a rough pencil sketch indicating where to look for it you have more materials to look into than me.
Tore

[tore]

Simon.
Further to my last post I may add that I believe the compensating pipe goes into the box and a pipe goes out of the box and act like a syphon for the compensatingwater from the box  to the bottom of the saddletank when in fuelmode.
Tore

[NZSnowman]

Hi Tore

A big redrawing of the piping under the decking!

There is little detail we know about this piping outside the pressure hull. The only thing we know for sure is the pressure hull opening (Figure 4).  I initially imagine the piping run just above pressure hull but I now know there is just not enough room to do this.

Next I needed to workout where the pipes enter the saddle tanks. I did this by matching deck hatches. I ended up using the four hatch covers for the exhaust gas and emergency blowing systems.

I also initially imagine the piping for the exhaust gas and emergency blowing systems run just above pressure hull but now I know there is just no room. So I move most of the exhaust gas and emergency blowing piping and Fuel oil compensating piping to just under the wooden deck. This was confirmed in a photo in the book The U-boat By Eberhard Rossler, where you can see one of the exhaust gas and emergency blowing systems pipe just below the deck.


Fig. 1. Openings.


Fig. 2. Piping.


Fig. 3. Hatch covers.


Fig. 4. Pressure Hull opening.


Fig. 5. Close-up.

[tore]

Simon.
Indeed substantial drawing work. A detail with regard to the saddletanks. I guess fwd and aft of the conningtower area the saddletanks have a sharp bend towards the pressurehull which facilitates the pipeconnections to the tanks, see drawing below. I don`t have a good picture of the casing deck in this area but I guess the deckhatches would give an indication of the location for the various deckoperated valves.
Tore
 

[tore]

Simon.
Mainvents fuel/ ballasttanks 2&4.
I had a closer look at the mainvents inlet to the fuel/ ballast saddle tanks 2 port and stb. compairing in it with a GA drawing of 1943 and adjusting it to approximately to your scaledrawing. When using the aft  battery hatch as you use as the fixed point, it looks to me that your drawing has the mainvent inletpipe about 650-750 mm further forward than on the GA drawing.
See drawing below.
Tore