Tores mailbox VIIC and VIIC/41 operation and technical details

[SnakeDoc]

We did not use any sophisticated systems for monitoring the air quality, only experience.

When on 7th May 1945 La Rochelle was surrendered to Allies, they captured decommissioned (but still afloat) U776 (type VIIC U-Boat).
The boat was overhauled and commissioned into the French Navy, where was named Laubie. She was in Service till 1961. She had three accidents:
- on 17th July 1950, during the exercises near the Morocco coast, during surfacing she was rammed by frigate La Surprise (ex HMS Torridge)
- on 2nd May 1960, near Alger, she was rammed on periscope depth by passenger liner Ville de Marseille
- on 22 September 1961 she was rammed (also on periscope depth, when schnorcheling) by submarine Espadon

Laubie also took part as a support for submarine La Creole during the Suez Crisis in 1956.
In 1958, her commander was lieutenant Bernard Louzeau, who (9 years later) became commander of first French nuclear sub - Le Redoutable.
Anyway, till 60s, French submariners also did not have any sophisticated systems for monitoring air quality. To deal with this problem, they took aboard small dogs.
Due to their small size and weight, the dogs reacted quickly on the air quality changes. When the dogs became lethargic - the air purification measures were taken.
On the board of Laubie, there was cocker spaniel name Folk. The dog loved retrieving the bottles, which were thrown away overboard by crew.

--
Regards
Maciek

[VIC20]

I guess Laubie Folk had some influence on how often they were surfacing… 3 times a day …poor conning tower

[tore]

Maciek.
We did not have any dogs, I Guess I would rather copy the miners using a canary bird. However we got the experience of foul air on the body and f.i. allowing one cigarette ( stupid) pr man. If the match did not lit, we were short of oxygen.
We had in fact some cooperation with the French exchanging ideas how to run a VIIC, a couple of our officers were on board one of the french VIICs for a few days I guess this was back in 1951-52.
Tore

[SnakeDoc]

I will quote circumstances of the last Laubie accident. On 22 September 1961 she served as the target for newly developed homing torpedoes. She had to schnorkeling, while Espadon had to detect her and attack with torpedoes. Commander of Espadon wanted to take up the position behind Laubie stern. He detected her and estimated her course visually - through periscope, using the relative position of the Laubie snorkel head and periscope. But he forgot, that Laubie Schnorchel was (unlike in case modern subs) in front of periscope. And so he took up position in front of Laubie.

--
Regards
Maciek

[VIC20]

Tore, when you fill a tank with the flooding & drainage installation where does the air which is already inside the tank move to?


and when you pump water into a tank is there a back pressure valve in the line (between the pump and the tank)?

[tore]

Mark.
Venting of the reg.tanks and Q.
 The Q as well as the regulatingtanks 1 and 2 port and stb have an inboard venting with sight glasses all ending in a muffler down at the controlroom bilge. The pipes and muffler from the regulating tanks 1 and 2 are fitted on the aft side of the attack periscope housing in the controlroom as seen on the sketch below.
Tore

[Don Prince]

Hello Mr. Tore,


What is the function of the black and red handles near the Main Pump?


See photo -


Regards,
Don_

[tore]

Don.
On valves having difficult access you have extensions of the valvespindle to the handle.On your photo the black handle has an extensionrod which ends in the air, I guess it could be meant for the suction valve for the main bilge pump. The red handle is a seawater board handle with extension to a board valve hard to identify right now. I`ll return when I get the answer.
Tore

[VIC20]

Thanks Tore.


Maciek do you also know the diameters of the different (air and water) lines of the flooding and drainage installation?

[Don Prince]

Hello All,


It was stated that D2, D3, and D4 was the ballast system...  Could we include the Negative Buoyancy tanks in that category as well?


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


Did you ever have to use the port e-motor I as a welding convector?  Did you see the e-machinist set things up on the Rotary Switchboard on Kaura (U-995)?


Regards,
Don_

[tore]

Don.
In a way may be, but I would not say Q (neg. buoyancy) tank was regular ballast tank. As you know it was a help to speed up the first stage of diving than anything else.
Tore

Hello All,


It was stated that D2, D3, and D4 was the ballast system...  Could we include the Negative Buoyancy tanks in that category as well?


Regards,
Don_

[tore]

Hello Mr. Tore,


Did you ever have to use the port e-motor I as a welding convector?  Did you see the e-machinist set things up on the Rotary Switchboard on Kaura (U-995)?


Regards,
Don_

Don.
We did not have welding equipment onboard. I most probably have seen the first electrician working on the switchboard,but cannot remember the reason why.
Tore

[Don Prince]

Hello Mr. Tore,


The Lime Water Plate: 26 indicate valve (a), I assume 4 different valves are used to spray lime water on the batteries.  Is the spray above, below, or where?  Where does the Lime water come from?  Is it a pre-mixes solution that's taken onboard when taking on supplies at port, or is this something that was mixed as needed?


Regards,
Don_

[NZSnowman]

Hello Mr. Tore,


The Lime Water Plate: 26 indicate valve (a), I assume 4 different valves are used to spray lime water on the batteries.  Is the spray above, below, or where?  Where does the Lime water come from?  Is it a pre-mixes solution that's taken onboard when taking on supplies at port, or is this something that was mixed as needed?


Regards,
Don_

Don, I believe pre-Type VIIC/41 it was above, on the VIIC/41's they change it to below.

I also believe they added lime to a pipe opening in the Control Room and then run water through the lime and pipe.

[Don Prince]

Thanks Simon...


Regards,
Don_

[tore]

Don.
In addition to Simons answer, good to see you are still active Simon, I believe the limespray system is very much similar to the corrosionoil system, very seldom used and as such based on a hose connection system which could be hooked up to f.i. the hand coolingwaterpump in the engineroom. I don`t believe the lime was stored in liquid state on board, rather as a powder in canisters, which could be mixed with water. I cannot remember we carried any lime on board neither ever used the limespray. However once it was a narrow escape though. When surfacing in a bad weather a huge wave hit us at-wartship  just when our stability was at it`s worst,( metacentric hight almost 0) and we got a list, I remember looking at the inclinometer, between 35 and 40 degrees and that is a lot. Of course we checked the battery compartments but didn`t find any acidspill.
Tore 

[SnakeDoc]

Hi Gentlemen,

I believe the limespray system is very much similar to the corrosionoil system, very seldom used and as such based on a hose connection system which could be hooked up to f.i. the hand coolingwaterpump in the engineroom. I don`t believe the lime was stored in liquid state on board, rather as a powder in canisters, which could be mixed with water. I cannot remember we carried any lime on board neither ever used the limespray. However once it was a narrow escape though.

American report on type IXC U-Boat provides some further details:

Corrosion protection for battery wells from spilled electrolyte is provided by means of the so-called lime-milk system (Kalkmilchanlage).  This is merely a pipe fitted with a funnel or hose connection at the upper end, and with a perforated section or a bilge strainer at the lower end in each battery well.  By pouring milk of lime (slaked lime in water solution) into the upper end, an alkali to neutralize the battery acid is, in older vessels, sprayed onto the wing bulkheads of the battery wells from whence it finds its way to the bottom of the battery well.  On newer vessels the solution is delivered directly to the bottom of the battery wells.     
The solution is normally evacuated by way of the drain system.

Source: http://uboatarchive.net/DesignStudiesTypeIXC.htm

When surfacing in a bad weather a huge wave hit us at-wartship  just when our stability was at it`s worst,( metacentric hight almost 0) and we got a list, I remember looking at the inclinometer, between 35 and 40 degrees and that is a lot. Of course we checked the battery compartments but didn`t find any acidspill.

The cells of the battery could stand the trim changes up to 60 degrees and the heeling up to 45 degrees without acid spill.

--
Regards
Maciek

[Don Prince]

Hi Maciek,


They mix a solution of Lime and water... Where is the solution held, and how does it get introduced into a water system that sprays the walls of the battery room with the diluted lime water?


Regards,
Don_

[SnakeDoc]

Hi Don,

They mix a solution of Lime and water... Where is the solution held, and how does it get introduced into a water system that sprays the walls of the battery room with the diluted lime water?

I don't know nothing more than quoted above. I suppose (as Tore said), that they held kali powder in canisters or cans, and mixed with water in buckets when needed. Then, the solution was poured into the funnel in the upper part of the piping. Solution flowing through the piping, was distributed over the battery compartment through the holes in the pipe (maybe the spray is too strong word). I suppose, that the piping was led around the compartment along the walls, and the solution "sprayed" the walls.


--
Regards
Maciek

[tore]

Don.
In the unlikely event of acid spill, (having a pitch exceeding 60 degrees and list exceeding 45 degrees) most of the acid ends in the battery compartment bilges and you want to neutralize that prior to pumping the bilges by the bilgepump. As Maciek says I believe the lime granulate or powder can be solved in water in any container or bucket prior to be pumped by the handpump. The lime distributionpipe close to the batterycompartments bilges has a hoseconnection where you can connect a hose to the handpump discharge hoseconnection. You can see both connections on the piping plan.
Tore

[VIC20]

Tore, does it really take several minutes to fill the regulating tanks completely with water?


Are there any tanks that could not be blown with the diesels? (except those that could be pumped only)

[tore]

Mark.
I guess the filling time shall vary depending on how you fill them, by natural flooding the filling pressure surfaced varies between appr. 2 mWC. and 0, capacity of one reg. tank 7,6 m3. piping appr. 100 mm., if you fill with the main bilge and ballastpump you might have a filling capacity of 1,3m3/min against 15 m WC however restricted to a pipe diam of appr 100mm., the reserve fuel and reg. tanks 1 have a capacity each of 4.7 m3 and have of course a shorter filling time. Otherwise, submerged the filling pressure by natural flooding varies  with the depth. I never logged the time , but I guess with the above input you are able to estimate the time, remember the inboard venting pipe which might influence the head due to resistance in pipe and muffler.
Only the main ballasttanks 1, 2 and 4 port and stb.,3 and 5 are possible to blow by exhaust.
Tore

[Don Prince]

Hello Mr. Tore,


I have a few questions about Plate 21 Water...


Q1.  On the Skizzenbuch they list Hot Sea water --- I don't see a heating element to heat the water?
Q2.  Cold sea water is just plain sea water and not chilled?
Q3.  Below Waste Tank 1 they show a pipe connecting to the Washing Water Line...  Is this really true?  They crossed waste water with washing water???  I sure hope not!  Perhaps that line should have gone to the drain of that sink...


Regards,
Don_

[Don Prince]

Post a photo....

[VIC20]

Thanks. Would you ever use the pump to fill the tanks when submerged?

[VIC20]

Q1.  On the Skizzenbuch they list Hot Sea water --- I don't see a heating element to heat the water?

maybe this?

		Sea water installation.
		To provide sea water collection in the galley, there is a branch off the cooling water manifold in the diesel engine room, which leads to the valve and a tap in the wash sink.
		The warm sea water installation branches off from cooling water head tank in the conning tower casing and leads to the washbasins in both W.C.s and to the wash sink in the galley.
		The discharge line of the auxiliary drain and trim pump branches off to the deck wash line.  A shower head can be connected to this line, attached to the net protector, and stowed again after usage.

and maybe the distilling unit produced hot sea water?

[Don Prince]

I thought about that, but doesn't the engine cooling water contain an anti-corrosion chemical for the diesel engine?


Don_

[VIC20]

No idea, but that sounds logical 

[tore]

Don.
The hot seawater pipe is a pipe connected to the headertank for the compensating watertank up in the tower casing. The headertank is topped up by a pipe from the hot engine coolingwater at the exhaustsilencer. The engine coolingwater is not a closed circuit and has no additives. Cold seawater is just natural seawater without any cooling. The wastewater tank 1 has only two pipe connections, the drain from the galleysink and the bilgewater suctionpipe.
Tore

[tore]

Don.
Further to my post above, on U 995 it is a horizontal electric pump taking its suction from the coolingwater of the exhaustmanifold alongside the engine and I presume discharge warm cooling water to the galley, I cannot remember this arrangement, but you can see same on photos of the forwad port side of the engine room and described by me previously on this thread. I have not seen any sketch showing this system.
Tore

[tore]

Mark.
I believe you fill the regulating tanks by natural flooding while submerged.
Tore

[Don Prince]

Hello Mr. Tore,


Thank you - I did find information on the hot water system and the anti-corrosion system.  Those systems are cross contaminated because the hot water passes through the same components as the anti-corrosion oil.  Not at the same time, but a residue will remain...


Questions
Q1.  Did the distilled drinking water have a smell or bad taste?
Q2.  I suppose the shower was with salt water and a special soap; did it work?
Q3.  The e-motors and bearings were cooled by sea water; did it have to be shutdown at a great depth because         of external pressure?
Q4.  How much anti-corrosion oil was brought on board for a 56 day mission?  55 Gallon drum?
Q5.  Was there a means to wash your clothes? or, just burn them after a mission?


Regards,
Don_

[tore]

Don.
The anti corrosion oil was never used when I was on board,(almost 3 years) and I guess it was not used permanently, more like an "impregnation" of the steel/ castiron. We did not analyze the coolingwater but it it was no sign or smell of any contamination. In my part of the world direct seawatercooling was commonly used on diesels and semidiesels particularly in the  fishingvessels without any anti corrosionprotection.
I guess the distilled water was primarily used for refill of the batteries, we never used same for drinkingwater.
During the WW2 real soap was rationed and hard to get and I remember the soap was not that great even in freshwater, so I guess the Germans used the shower just to have a rinse and cooling off,  we did not used the shower, but during long missions we did most of the washing in seawater and you could have a special soap for that.
Although we had standard procedure to shut off as much as possible of the cooling watersystems going deep, I believe for the e-motors and thrustbearings the cooling circuit was open at depths down to 100 m.
We did not have any anticorrosion barrels on board.
We did not have any laundry facilities on board, however except for long missions, a submarinetender was usually in the neighbourhood which had the facilities, otherwise some of the worst clothings had to be dumped as you say.

[Don Prince]

Hello Mr. Tore,


One of the British reports states there is a master blowing valve in the engine room for blowing the ballast tanks with diesel exhaust one at a time.  They state that the two muffler valves are shut to blow the ballast...


I see it this way...


The blowing is carried out by opening at least one of the Muffler Valves (f) in the engine room and closing its accompanying Exhaust Gas Outboard Flap Valve (e) to re-direct gases to the blowing manifold.  One ballast tank is blown at a time.  The engine in use for blowing may be running light or propelling and is run at a speed of no less than 300 RPM.  It is important that the Exhaust Gas Outboard Flap valve should not be open at this time.  If it is, the tanks will vent at a slower rate because you will loose substantial exhaust gas pressure through the muffler.  The second diesel would be re-charging the batteries after a dive...


Would you ever blow the ballast tanks with both diesel engines?  It looks like you could according to the drawing...


I do not see a master valve between the blowing manifold and the muffler valves...  Am I missing something?  What would be the proper blowing tank sequence?


Regards,
Don_

[tore]

Don.
When you start exhaustgas blowing, one of the diesel is started the normal way having the inner and outer (muffler) main exhaustgas valves open, when the engine is running smoothly you adjust the exhaust pressure by throttling the main exhaust mufflervalve, the inner main exhaustvalve is fully open, as you open the mainblowing valve admitting the exhaustgases to the distribution panel in the controlroom. I don`t think as a rule one  MBT is blown at the time. The ruling factor is the trim of the submarine as an excessive faulty trim would lead the exhaustgases to the MBT having the lowest resistance and upset the the trim even more, hence you adjust the distribution of the blowing in the controlroom. We used only one diesel for blowing, remember, this was usually a fairly slow process (10- 15 min) at a semisurfaced position using only 5 m WC pressure and one diesel emitted ample exhaustvolume for blowing the tanks. The US and RN submarines used electric blowers for this last stage blowing, which primarily is used for saving HP air.
Tore

[tore]

Don
Reading my yesterdays post I realize you might get the impression that the diesel exhaust blowing pipes enters the controlroom, for the sake of order it is only the distributionvalve spindles and handwheels which are in the controlroom the distribution valvechest and pipes are outside the pressurehull.
Tore

[Don Prince]

Hello Mr. Tore,


Thank you for the update...  The only thing that surprised me was the Outboard Exhaust Valve was not fully closed when blowing the ballast.  I guess once you establish the correct exhaust pressure by adjusting the valve, then excessive back pressure would affect the engine performance...


Regards,
Don_

[tore]

Don.
Shutting the exhaustsilencer flapvalve would have led to excessive exhaustpressure almost immediately. The dieselengine acts like a piston pump having a piston displacement of 0,057 m3 for every 2.nd revs ( 4 stroke). With 6 pistons and say 300 revs/min this would be about 50 m3/min exhaust. Compressing this to 1,5 ata (max allowable blowingpressure) would give appr. 34 m3/min exhaustgas at 1,5 ata, which is far to much for blowing the MBTs. Thus the silencer flapvalve had to be partly open and as the pressure varied was constantly adjusted by the engineer maintaining the correct pressure. The exhaustblowing of MBTs required ( in the controlroom) a constant monitoring of the pressure to each tank as the resistance of the tanks varied according to the depth of the Kingstons and floodgates ( 1 and 5). I have tried to put up a sketch showing the variation at 2 degrees bow up surfacing. For the saddletanks in ballast configuration, the saddletanks Kingstons are substantially higher up than MBT 3 and having the least exhaust blowing resistance of all MBTs.
Tore

[SnakeDoc]

Hi Tore,

The dieselengine acts like a piston pump having a piston displacement of 0,057 m3 for every 2.nd revs ( 4 stroke). With 6 pistons and say 300 revs/min this would be about 50 m3/min exhaust. Compressing this to 1,5 ata (max allowable blowingpressure) would give appr. 34 m3/min exhaustgas at 1,5 ata, which is far to much for blowing the MBTs.

Do you think, is it doable, to blow ballast tanks using diesel engine as compressor, which is driven by electric motors?
I mean the situation, when there no compressed air left in the air flasks to blow or start diesel (other option - to start diesel engines by electric motors).

--
Thanks, regards
Maciek

[tore]

Maciek!
Interesting twist. To my opinion using the E-motor as at starting motor would probably work. In that case I would start turning with the indicatorcocks open, then shutting same when revs are adequate for switching to fuel and you would probably get ignition. Using a 400 mm cyl.diameter 4stroke engine as an electric driven compressor would probably work surfaced,  the air pressure would be limited but probably sufficient for LP blowing the ballasttanks. If out of HP air I would rather start the engine by the E-motors and blow the MBTs by exhaust. By the way I vaguely seem to remember we once started the engine by the E-motor as a test.
Tore

[VIC20]

Tore, I guess this is hard to tell but how fast did the depth gauges respond to changes of depth? I want to let this change look real on my gauges. Was  the 25m depth gauge needle more "dancing" in really heavy seas or was is sluggish with just a little movement of the needle?

[tore]

Mark.
The depth gauge 0-25 m is an ordinary direct manometer and as such has an immediate respondtime. I cannot remember any large fluctuation due to surface waves, however at heavy swell the submarine moved up and down and the depthgauge showed  the variation of depth immediately. Under such conditions keeping the periscope depth was very challenging. You could feel the swell down to more than 50 meter during a severe storm. By the way on U 995 it looks as if somebody has pinched the greater depth gauge having coloured sections on the dial.
Tore

[VIC20]

Thanks Tore, another thing… I've "connected" the compass to my (new upgraded) boat today and this is how the sea affects the heading of the boat at full speed - do you think that is within normal range?


http://hessburg.com/Screenshots/Heading.mov

[VIC20]

Tore, what exactly do they mean by "Beide Maschinen 10 weniger"? 10 what? 10 RPM? And when they set it to "Achtung" what does that mean for the people in the engine room?

[tore]

Mark.
I tried several times times to connect your link, but somehow I can`t get connected. "Beide maschinen 10 weniger " would mean 10 rpm lower I guess we never used that. Achtung would be the same as "stand by" on any engineroom telegraph meaning the engine crew should be ready for action, being mostly for starting up or maneuvering. On a submarine it could be ready for surfacing, diving, schnorchling, batterycharging  etc. as well.
Tore

[VIC20]

Tore, I've uploaded it to youtube: http://www.youtube.com/watch?v=RKR3UCv_l9I&feature=youtu.be


(rudder is set to 0°)

[tore]

Mark.
Amazing. I assume it is the gyro repeater and as such I believe OK.( I am not a navigator). The general impression is as you have said previously, a simplification on the bridge to the essentials for the game. However the behaviour of the U boat in heavy sea seems a bit smooth and fast, like a hot knife through butter. The lucky buggars on the bridge in your sub. seems to be very dry, unfortunately there was a lot of spray and some times even a wave filled the bridge under the weathercondition similar to what you are showing. Usually the people on the bridge wore oilskin dress and a southwest hat during these conditions, even then they got pretty wet.
 I see you have introduced a RN flowerclass corvette and an US Fletcherclass destroyer as escort for the convoy, I am not sure if these two vessels operated in a joint escort on the North Atlantic convoys, definitely the flowerclass corvette was in the escort.
But anyhow I am impressed what you are able to make.
Tore

[Don Prince]

Hello Mr Tore,


Do you have a photo of the valve wheel for the Outter Exhaust Flap Valve that is adjusted to setup up the pressure for blowing the ballast.  I want to be sure which valve was used for blowing in the engine room...


Regards,
Don_

[Don Prince]

Also a question on the Diesel controls...


The wheel to the right is used for turning on the air pressure to start the engine.  The next lever with a squeeze lever to unlock and the markings are Top "Dis-engage" and the bottom "Start"...  The next lever has the squeeze lever and a button.  If the squeeze level locks the lever in place, then what is the function of the button?


I assume the lever furthest to the left is the fuel control and the marking from top "0" to the bottom "55"...


Would the sequence be:
1.  turn the wheel to supply starting air
2.  move lever to start
3.  When sufficient speed - move the fuel lever to a low amount
4.  Move lever to Dis-engage
5.  Turn off starting air
6.  move fuel lever to get higher RPMs


Regards,
Don_

[tore]

Don.
Main (Group) exhaustvalves.
Down below are the 6 port and stb main exhaustvalves we have discussed.
Tore

[tore]

Don.
Starting procedure for GW engines.
I am not sure which plan you are referring to, mentioning "disengage" on the starting lever. But basically you are right in your assumption as to the starting procedure. However in addition to this system you have some interlocks and lever for engaging  the supercharger (Roots blower) and shutting the natural aspiration. Further you can see some rudiments from the direct reversible system so it is easy to be confused. I guess the small wheel on the fuel lever is for fine control.
Tore

[VIC20]

However the behaviour of the U boat in heavy sea seems a bit smooth and fast, like a hot knife through butter.


…

 I see you have introduced a RN flowerclass corvette and an US Fletcherclass destroyer as escort for the convoy, I am not sure if these two vessels operated in a joint escort on the North Atlantic convoys, definitely the flowerclass corvette was in the escort.
But anyhow I am impressed what you are able to make.
Tore

Thanks


The new buoyancy is still not completely implemented. I'm currently busy with that these days.


I have the PC461 Class as small escorts in range of the american coast. The flower class will sail with british destroyers (currently only have an O class)

[Don Prince]

Hello Mr. Tore,


The one strip beside the lever reads Anlassen (Start) and at the top Detrieb (Uninstall drive or Dis-engage)?


Regards,
Don_

[VIC20]

The one strip beside the lever reads Anlassen (Start) and at the top Detrieb (Uninstall drive or Dis-engage)?

Don, there is no word "Detrieb" in the german language. Do you mean "Betrieb"? (operation)
http://www.dict.cc/?s=betreiben
http://www.dict.cc/?s=betrieb

[Don Prince]

Hi Vic,


I seen the error after I reviewed the reversing mechanism...  I could only partially read the 2 items left on the metal plate.


The lever to the right has 4 positions:


Stop       --  top
Operate
Reverse
Starting  --  Bottom


So the starting sequence would be:
1.  Turn the wheel to supply starting air
2.  Move the right lever to starting
3.  When sufficient rpm, move the left lever to a low fuel amount
4.  Move right lever to operate
5.  Turn off starting air
6.  Move left lever to higher rpm


Regards,
Don_

[tore]

Don.
Almost correct, but as soon as the cylinders ignite you move the starting air handle back to shut off the air to the cylinders. and then shut the starting air supply valve. The reason is that you  disengage the cylinder startingvalves from the camshaft as soon as possible shutting the valves.
Tore

[tore]

Mark.
The way the VIICs behaved in the rough sea fascinated me and the pitching gave a spectacular view. As you know the designers made some effort to reduce  the pitching by introducing the watertight bow and stern as well as on the VIIC/41s, the Atlantic bow, having a flare. The floodgates of the watertight bow and stern contributed even more to the dramatic sight of spray.
I don`t know much about the graphics but as I understand you are busy with the subject right now I have adopted one of my paintings of KNM Kaura ex U 995  (VIIC/41) to show my ideas about the spray. In the game graphic, the spray is almost absent and the sea gushing over the casingdeck drains very quickly. In real life the sea was almost constantly covering the casing deck.
The movie Das Boot gives an excellent impression of the real thing. I am not sure if it is feasible to achieve these effects in a game programme so excuse me for interfering.
Tore

[VIC20]

The mobile devices can't handle much more spray than shown in this video: https://www.youtube.com/watch?v=5PYCpmEKu5U&list=UU03RMMpKkHkZVROUHFTWYVA


Spray is transparent and everything that is transparent costs a lot of performance because screen pixels has to be drawn several times.

[tore]

Mark.
I had the feeling it was something like that
Tore

[Don Prince]

Hello Mr. Tore,


The lever to the right has 4 positions; Stop, Operate. Reverse. and Starting.  When is the Operate position used?


Regards.
Don_

[VIC20]

Tore, do you remember the color of the isolators(?) on this (colored) picture?

[tore]

Don.
The starting lever has a nameplate which is a rudiment from the direct reversible dieselengine, hence  the 4 positions. First of all, plate 29 has a wrong translation "Umsteuer"does not mean "reverse" it means shifting of the camshaft to ahead or astern position. As the direct reversible engine required a lot of complicated operations as, lifting the cylinder valve rollers up from the camshaft, moving the camshaft axially, lowering the rollers down on the camshaft, starting again etc. they combined parts of these operations in the starting handle by adding links and cams, including various interlocks,  to the startinglever movements. During these timeconsuming prosesses the handle had a position "operate". On the non reversible execution the starting lever had only two functions moving the rollers down ( start) or moving the rollers up ( run) from the camshaft, thereby distributing starting air to the cylinders (start) and shutting of same (run) soon as you achieved the proper revs.
Tore

[tore]

Mark.
It is hard to remember such details more than 60 years back. However I thougth they were dark green when I made my model, but it could be dark brown.
Tore

[Don Prince]

Hello Mr. Tore,


On Plate 29, what does the shaft Lenkerwelle do?  The stop and the operate positions have the same valve configuration; that seems redundent?  I think I was wrong on my start sequence; I believe 1st should move lever to start, and then turn on the air.  If I turn on the air first and start moving the lever down to start; I pass reverse (or lifting and reversing) and I would not want that to start???


There is a lot to think about on plate 29...


Regards,
Don_

[Don Prince]

Now, that photo I had of the engine levers where the starting lever only had two positions; Stop and Starting.  U-995's diesel engine did not have reversing...


Don_

[VIC20]

…On Plate 29, what does the shaft Lenkerwelle do?  …

A Lenker is something for steering. Sounds like it has something to do with dive planes or rudders… or maybe the governor?

[tore]

Don.
Lenkerwelle is a shaft going along the camshaft. One of the purposes is supporting the  leverarm for the cylinder startingvalve camshaft roller, the other (for direct reversible engines) having  cranks and rods connected to the HP fuelpump camshaft rollers pulling them away from the fuelcams on the camshaft when axially moving same for changing direction of rotation, see plate 30.
I don`t think your last proposal for starting is the correct one. You first open the main starting air supply valve admitting starting air to the cylinder starting valves and startingair manifold. Then you move the startinghandle to start, on a direct reversible engine you pass the "umsteuer" maneuvering position and the run position nothing happens, the run position is only the ventingvalve open the others shut. On the maneuvering position the air is only admitted to the slide for the ahead/asternhandle which remains in the position for rotation  selected by the handle.
When the starting handle is in start position  air is admitted to the top piston on the cylinder startingvalves pushing the rockerarm down and engage the rollers to the starting cams, on direct reversible engines to the cams which are selected by the ahead/ astern handle, and the engine start to run on air. When you obtain the proper revs you move the handle to "betrieb" or "run" the valves supplying air to the "umsteuer" mechanism and top of the cylinder starting valves are shut, the vent valve on the air manifold opens and the spring under the top piston on the cylinder starting valve  is forcing the piston up which lift the starting valve rollers from the camshaft.

[tore]

Don.
Yes the U 995 as well as the other of our VIICs did not have direct reversible engines. Thus I was never operating a direct reversible GW engine.
Tore

[Don Prince]

Hello Mr. Tore,


Can you please explain this sentence...


"On the maneuvering position the air is only admitted to the slide for the ahead/astern handle which remains in the position for rotation selected by the handle."

Does it mean the handle has to stay in the reverse position in order to start the reverse process?

Regards,
Don_[

[tore]

Don.
When you open the main starting supply airvalve, air is supplied to the starting air manifold. If you then put the startinghandle in the "umsteuer"/"reverse" position you open two valves in the airmanifold, 1. air supplyvalve to the  "umsteuer schieber" or slide and 2. the ventingvalve. The air is supplied to the ahead/ astern "reversing" slide, which control the displacement piston for the camshaft. This means the engine is ready for maneuvering. The reversing slide is operated by the ahead/astern handle, removed on non reversible engines but you still see the rudiments. The slide has only two position, ahead or astern and. If at the starting operation the starting lever passes the revers position nothing happens as the air only keeps the reversing mechanism in the ahead/astern handles status quo position.  Thus the starting handle has to be put in "umsteuer" position in order to be able to operate the ahead/astern handle on the direct reversible engine. Below I have tried to sketch (red) the diagram in the "umsteuer" (revers) configuration with the ahead/astern handle placed in ahead position . Further is a picture of the revers handle rudiments on the U-995 engines. Further to the basic movement,  the reversing system consist of a number of interlocks preventing the handles to be moved at the wrong times, which I for simplification have omitted at this stage.
Tore

[OldNoob]

Hi Tore!  quick noob question. On the inner walls of the upper conning tower of the VIIc. Are those wood slats or steel armor slats? If you answered this already im sorry. ive browsed through this thread but may have missed it.

[tore]

Hi OldNoob.
For those VIICs operating in the Arctic I guess you had wooden slats which I assume should prevent sticking to the freezing cold steel. The armoured conningtowers were normally armoured plates often included in a shelter armoured box mostly on the starboard side as protection from air machine gunattack. I cannot remember we had any of the kind on our VIIC`s.
Tore

[OldNoob]

So Teak is wrong.

 Where in the world did i get the idea they were wood? LOL

[tore]

OldNoob.
Teak during WW2 in Germany?
Tore

[OldNoob]

OldNoob.
Teak during WW2 in Germany?
Tore

Indeed. Senility on my part. Thank you for getting me straight.

[Don Prince]

Hello Mr. Tore,


Have you ever got your general U-Boat wiring diagram copied?  I believe a great deal could be restored if it were in a digital format?


My main reason for this post....  I have completed my book "Skizzenbuch" for the U-Boat Type VIIC and I would highly regard your personal opinion about the book.  It's 75 percent diagrams and photos with a lot of your words and advice to me about technical matters.  I have been studying the U-Boat since 2003, but I have learned a great deal in the past few months from this web site and you in particular (Thank you!)...


If you could send me [donprince5207@comcast.net] your email address, then I could send you a link to the dropbox that contains the pdf file... 


Kind regards,
Don_

[tore]

Don.
I am  up at my farm way out in the deep forrest of Norway for the summer and I haven`t seen my grandsons for weeks, however they are coming up this week end and I shall discuss the matter then. As to your skizzenbuch I am looking forward to seeing it and shall send you an Email.
Tore

[VIC20]

Tore, do you remember if this symbol thing had a color? I think I've read something somewhere in the manual once about colors of these symbols.

[SnakeDoc]

Tore, do you remember if this symbol thing had a color? I think I've read something somewhere in the manual once about colors of these symbols.

Mark, manual says about red marks.


--
Regards
Maciek

[VIC20]

Thanks - the other one (rounded) has no specified color right?

[tore]

Mark.
We had only one VIIC with the old compasscasing (U 995)the others had the new version and by the way  on the present day museum U 995 they have installed the new compasscasing for some reason. We did not use these symbols, thus all the symbols were painted as the rest of the superstructure. On the new compasscasing for the other VIICs I can`t remember it was any symbols. On a black and white photo of the old U 552 it seems that the symbol has the same tint as the compasscasing which obviously is painted black . But as Maciek says manuals is mentioning red.
Tore

[VIC20]

It's boring without colors  I'll use red.

[Don Prince]

Hi VIC20,


I built a 1/32 model of U-96 and decided the Laughing Sawfish was a green color based on the following article by Dougie Martindale...



http://amp.rokket.biz/docs/laughing_sawfish.pdf


My Brass Tower 1/32nd model....


Regards,
Don_

[Don Prince]

FYI....  That fishie is hand painted and not a decal...


Don_

[VIC20]

I built a 1/32 model of U-96 and decided the Laughing Sawfish was a green color based on the following article by Dougie Martindale...

http://amp.rokket.biz/docs/laughing_sawfish.pdf

Don, I've read the article in january and opted for black


The lime green metal sawfish pennant in the article is pretty funny because they think so much about the color that they don't realize those 2 pennants are not identical but they say it is the one of U 96.
Look at the rear fin to body, at the eye, at the mouth and the lenght of the "saw". A completely different thing.

[tore]

Mark.
As you probably know the square with a cross is the marking for the hatch to the emergency ballasttank blowing and the circle with a cross is the external emergency air supply to the ventilationsystem inside the boat. The hatches were made for easy access for divers to the connections inside the casing. Like the system for valve handles and wheels having different shapes for easy identification in bad light, I assume the marking symbols were made raised.
I was a scubadiver for many years and I remember how the colours disappeared even at small depths and the red was first to be eliminated , blue the last, possibly because of the wavelenghts. I was told that nature used less energy to produce red colour hence as a camouflage many fishes were exotic red on the surface only to become black ( which required more energy to make) at modest depth. To make the identification red for divers at depth below say 8-10 meters seems strange to me as you don`t see the red, unless you have a torch of course.
Tore

[VIC20]

That's an interesting point. I guess some clerk decided that because of other regulations.

[tore]

Don
Q tank, your Skizzenbuch.
I guess your description of the Q tank system might be a bit confusing. Then port and starboard Q have a combined common blowing and venting pipe which is  drawn at both plate 7 and 17. The boardvalve h on plate 7 is the same as boardvalve f at plate 17.  The hullvalves h and f are the hullvalves for blowing as well as venting.The common main blowingvalve is controlled by the red wheel at stb side and the common main ventvalve is on the port side ending in a muffler under the steelcabinet. See my sketch below.
Tore

[Don Prince]

Thank you Mr. Tore,


That is exactly what I need is someone with a close eye for my mistakes and not making a good point.  I have have added a page with your well designed illustration and comments.


As I look at Plate 7 the hull valves are labeled (h).  On Plate 17, I believe the hull valves are labeled ( i ) and not (f)?


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


I have a question about the Blowing Valve...  The one indicated on your drawing has another valve a little down and to the right (not Labeled)?  Is that unmarked valve the actual Blowing Valve?


Regards,
Don_

[tore]

Don.
 The valve nominated f by me could very well be an i . The small valve wheel down right of the common blowing valve has nothing to do with the Q common blowing valve. The blowing air goes directly via the common blowingvalve into the common Q venting/ blowing crossoverline and has only the hullvalves of the Q port and stb. as a possible separate control valve.
Tore

[tore]

Don. Skizzenbuch.
Ballast tanks page 230. I guess you are mixing up MBTs 1 and 5 with bow and stern buoyancy tanks. MBT 1 and 5 are both belonging to the main ballast system and plays an important role int the diving procedure. The bow and stern buoyancy tanks are above the surfaced waterline and do not belong to the ballastsystem but is primarily used for reducing the pitching on the surface in an effort (together with the flare of the Atlantic bow) to reduce the seaoverflow and spray during surfacecruising. 
The standard diving procedure for a VIIC ( not crashdive) would be: open vents for MBT 5, 2 and 4 port and stb.( when in ballastconfiguration) and 3. Then you get your bow down angle about 7-8 degrees ( using the hydroplanes as well), then after  say 4-6 seconds open the vent for MBT1. You should aim to have the tower wind deflector at the seasurface simontaneously with the stern which would give you an 7-8 degrees bow down angle, sufficient to have enough water above the propellers and aft hydroplanes for max efficiency, thus MBT 1 and 5 are indeed very important as ballasttanks. Down below is a sketch I made for the correct diving procedure and a photo I made once from a Shackleton anti submarine plane showing my KNM Kaura ex U 995 in a correct routine diving position 8 degrees bow down.

Tore

[tore]

Don.
Skizzenbuch page 96, cooling water system main engine.
I don`t fully understand the statement: "The coolingwater has two entries per cylinder to effectively maintain the proper operating temperature". Down below is a cross section drawing of the GW dieselengine having for each cylindersection an inlet branch from the common cooling waterpipe along the outboard side of the engine, just as the green pipe on your pipescheme. The green colour indicates the cooling water entering the bottom of each the cylinderjackets, flowing upwards via a cooling waterbend to each  cylindercover having an outlet to a distribution cock with a branch off to the coolingjacket of the exhaustvalve which require only a part of the total coolingwater for each cylinder, the remainder bypasses the exhaustvalve and joins the outlet of the coolingwater for the exhaustvalve before entering the common exhaustmanifold coolingjacket and then the cooling of the groupexhaust valve etc before going overboard as mentioned by you. As this system is based on a pre WW2 technique there are no thermostates, each coolingwater pipe out from the exhaustvalve has a thermometer and the engineers had to adjust the cocks in the system to maintain the correct temperatures.
 A possible confusing part of the scheme is the rather heavily drawn second pipeoutlets from the engine joining the cooling waterbends  over the manifoldflanges, end of the manifold and the bends over the flanges for the groupexhaust coolingcasings. However these pipes are only the venting(deairation) pipes of the system. The intricate deairation is due to the fact that air in the system upset the cooling waterflow and you might get hotspots and possible cracks as a consequence.
Tore

[Don Prince]

Hello Mr. Tore,


Again Thank you...


I have corrected the info about MBT 1 and 5...  I thought someone told me that they were not part of the main ballast system.  This was contrary to what I have always understood?  Oh well, I'm back in sync with the ballast system.


As for the water cooling for the Krupp engine, that was just my dumb mistake about 2 lines (I think I may need a new pair of glasses, and probably should have that cataract surgery that I've been putting off for several years!) .. 


Thanks for the corrections


Regards,
Don_

[tore]

Don.
Just a few minor remarks to your skizzenbuch. You have some remarks to plan 13 coolingwatersystem and  mentioning the various components getting cooling. I should mention the branch off to the propeller shaft packingboxes as well. Via valve c4 they get their cooling. 
On page 47 you are mentioning the various persons at diving station in the controlroom putting the siderudder helmsman up in the conning tower. At battlestation some COs preferred to have the helmsman in the tower however at divingstation he usually was placed in the controlroom together with the hyroplane operators. At diving it is important that the bridge can be cleared for people quickly and normally the CO and lookout rush down in the controlroom. The conningtower is quiet cramped and a helmsman is a bit in the way. At surfacing the CO is normally at the navigation periscope in the controlroom giving his orders to the helmsman prior to surfacing, it gives a better communication to have him at his place in the controlroom. Thus we normally placed the helmsman in the controlroom and only some time during battle station he was in the tower. As I said just minor remarks.
Tore

[Don Prince]

Thank you Mr. Tore,


I made the appropriate corrections and I can't thank you enough for your help with my Skizzenbuch...


Regards,
Don_

[tore]

Don.
Skizzenbuch fueloil watercompensating.
The simple yet ingenious system of selfregulating seawatercompensating fueltanks might be a bit hard to understand. Basically the system works in the same manner for the internal as the external watercompensated tanks. There are several reasons for using watercompensating. 1. The compensating of weight loss due to the fuelconsumption although the seawater has a higher specific gravity, the weightcompensating being plus or minus is less. 2. The free surface effect is reduced which is important particularly to a submarine. 3. It gives a simple way of transferring the fuel in the system.
The use of the saddle ballasttanks 2 and 4 port and starboard as fueloil tanks require special precautions. The mainventing system has to be blocked and secured shut. This is done by shutting gatevalves and not cumbersome blindflanges in the ventduct between the tanks. The ventduct between the gatevalve and the mainvent has a drain/ventvalve which has to be open. The gatevalve and the drain/ventvalve are operated from the casingdeck. When diving the mainvents for 2 and 4 are open permanently and not shut while being submerged as ordinary ballastventing so you let the seawater fill the ventpipe to the gatevalve, hence the open vent/drainvalve, and the ventduct is compensated and pressure equalized.
As the tanks have a HP blowing, the hullvalves for the blowing are shut and secured to prevent structure damages.
The compensating water pipes goes from the headertank to a small chamber ( about 1,5 % of the tankvolume) at the bottom of the tank., from this chamber goes a short pipe into the tank bottom and an equalizing pipe direct to the sea. The two connections are controlled by a double seated selectorvalve operated from the casing. The valve has only two positions, either to the fueltank or direct to the sea. When in fueltank configuration the Kingstons are shut and the selectorvalve open to the fueltank and thus shut to the sea.
In the ballastank configuration  the gatevalves are open, the drainvalve shut and the main ventvalve operated as an ordinary mainvent valve. The compensating selectorvalve is put in direct connection with the sea and shut to the tank thereby the headertank is equalized when diving and submerged. The HP hull blowingvalves are opened and secured. In this way when blowing the tank air or pressureized water cannot enter into the compensating system via the selector valve. The compensatingpipes ends appr 10 cm lower than the fuel venting pipe intake, acting as a waterdischarge pipe  by fueling described by you. This allows time to stop fueling and thus prevent any fuel entering the compensating watersystem.
I know it became a long story and may be a bit complicated  so I tried to make some sketches as shown below.
Tore

[tore]

Don.
 Further to my post this morning I have made an additional sketch indicating the various valves involved in a fuelconfiguration of the saddletanks. As a matter of interest I made a quick calculation of the weight compensating for the difference between the saddle fueltanks filled up with fuel and empty but compensated with seawater. The total for all 4 tanks would amount to an extra weight of about 6.5 tonnes which then had to be taken out from the regulating tanks, in case of not being watercompensated the loss of weight would have been about 43 tonnes which would have to be pumped into the regulating tanks. With a total regulating tank capacity of 24,6 tonnes this would have been impossible. If you do the same for the internal fueltanks, the total weight increase by seawater compensated tanks would be about 9,2 tonnes totalling with the saddletanks 15,7 tonnes and still possible to compensate with the regulatingtanks but without seawatercompensated tanks the loss of weight would have been about 61,5 tonnes, totalling with the saddletanks about 104 tonnes lighter which had to be compensated.  This is of course a play with figures with no realistic use but is just an example of one of the advantages by watercompensating.
Tore

[Don Prince]

Hello Mr. Tore,


Thanks again....  You sure are a wealth of knowledge.  Updating my book..


Regards,
Don_

[tore]

Don.
On page 140 you have a photo of the U 995`s GW engine. On page 141 you say: " The MAN engine looks to be the new diesel engine generation...."  It could be misunderstood as you are referring to the photo of the GW engine.
Starting procedure.
You have a description, possibly mine, of the general starting procedure on page 135 . On page 101 you are referring to a startingprocedure after surfacing, possibly mine, particularly mentioning air blowing of the cylinders prior to starting to prevent waterstroke. I would suggest you include the latter in the description on page 135 because you blew the cylinders after a long stop as well not only after surfacing and particularly after schnorchling. You would always be sure the cylinder were clean and free from water as you could have an ordinary coolingwater leakage into the cylinder as well.
Tore

[tore]

Don.
Skizzenbuch group exhaustvalve.
 On page 97 you are using one of my bad rough sketches to illustrate the group exhaustvalve casing passing the pressurehull and the grinding of the outer (muffler) flapvalve. This sketch might give a confusing image as it is a sideview of the aft/forward outboard system connected to a sideview of an at wartship inside system. May be you should indicate a line were the outer alongship pipe is turned 90 degrees to the aft as I have tried to indicate below.
Tore

[Don Prince]

Hello Mr. Tore,


The Black and White photo was supposed to be a MAN Diesel Engine...  Note the control levers are of the MAN design.  That is the first difference I see between a GW and a MAN design.  Am I wrong on that photo?


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


The outer flap valve - what drove the gear shaft to raise the plate? Was this manual or part of the pneumatic drive?


I know the inner flap valve rotational drive was manual and I assume the raising of the plate was manual as well?


Regards,
Don_

[tore]

Don.
The black and white photo is taken on board U 995 as a museumboat during the last 10 years and is showing the GW engines with a few minor modification since my time on board. The starboard engine has a new type of fuel filter, the port the original. The flooring is the museumversion having  modern floorcoverings, not original. The MAN engine is entirely different. The most significant apart from the maneuvering stand is the turbocharger in the aft end, having double inlet airducts on the inboard side from the turbocharger and the double exhaust pipes to the turbocharger on the outboard side. GW engines have common airduct directly underneath the exhaust manifold on the outboard side and the exhaust goes directly overboard as the engine has a mechanical driven Roots blower. Crankcase doors on MAN are round on the GW square. Lp fuel supplypump is on the aft end on MAN and in the forward end on the GW, so I am afraid somebody told you the wrong story.
Tore

[SnakeDoc]

Hi Gentlemen,

both engines - MAN and GW were designed before war, so one can not say, that MAN engine was new generation.
Moreover, one can wonder, why Kriegsmarine chose GW engine as the primary propelling unit for type VII U-Boats
(MAN engines were installed less frequently) - especially knowing, that MAN engine was lighter and had lower
fuel consumption. The answer is that MAN engines (in the 9-cylinder version) were manufactured for type IX U-Boats,
while the other factories manufactured GW engines for type VII boats.

The photos of the MAN engines can be found here:
http://u-historia.com/uhistoria/tecnico/articulos/motores/motores.htm

--
Regards
Maciek

[tore]

Don.
The outer flapvalve was manually shut by a handwheel,external rods and bevelgear. The inner valve was manually operated by the same type of handwheel as well. Both wheels have holes in the  wheel circle for putting in a bar thus being able to get extra torque moment for shutting. see my picture below.

[Don Prince]

Thank you Mr. Tore,


Again, I will make the appropriate changes...  I am very surprised that U-995 had two very different control levers units on the what I assume to be the original GW Diesel Engines.  That sure confused me!


Does anybody have a good high resolution isle photo of two MAN Diesel Engines in a Type VII U-boat?  I sure don't, and I don't see one on the web so far...


Regards,
Don_

[tore]

Don.
I don`t have a high resolution photo but below you see the significant difference of the maneuvering stands of the two engine types, although the MAN engine of the U 166 being a IXC  from 1940- 1941 and as such having the 9 cylinder direct reversible execution, the maneuvering stand was the same as a direct reversible 6 cylinder MAN. The MAN engine was equipped with a turbocharging system which means utilizing the kinetic and thermal energy in the exhaustgases to drive an exhaust gas turbine attached to a rotary compressor in the aft end, this system could be used over the whole output range. Although the system had been known for years, the practical use was not common in the latter part of 1930, primarily because the efficiency is depending upon fairly high temperatures which was limited by the material heat resistance of the turbine blades which at that time was a material challenge. The GW engine technique was more conventional technique of the 30this with a Roots blower which only could be used at higher output and thus required a complicated system of clutches and interlocks. Moreover the specific fuelconsumption was higher on the GW engine letting the residue exhaustgas energy disappear directly overboard.
Tore

[tore]

Don,
A high resolution photo of the MAN 6 cylinder engine is hard to find, below is the best image I found showing a 6 cylinder MAN M6V 40/46KBB.
Tore

[Don Prince]

Hello Mr. Tore,


Does this look like a MAN Diesel room on a VIIC?


Regards,
Don_

[tore]

Don.
It is very little engine and much of the crew on the photo, but the crew is very high up head above the engine top and it is very narrow between the engines which could indicate small engines. If you look at the framing it indicates a small hull as well. I guess this could be one of the older small submarines like  type IIB, however these submarines had MWM RS 127S 6 cyl. engines and it does not look like a MWM.
I don`t think it is a MAN 40/46 as the airduct along the engine is round and not rectangular moreover there are some internal gatevalves up under the pressurehull which does not exist on a VIIC. My guess would be: not a MAN engine and not a VIIC, possibly a smaller coastal submarine.
Tore

[tore]

Don
I was able to find a more comprehensive photo of the engine assumed by you was the MAN mainengine alternative of the VIIC engine. The MAN submarine engine underwent a number of design developments from the early natural aspirated engine ,I believe in the late 1920this, via a mechanical supercharged version, to a Buchi turbo charged version in the 1930this and to the last turbocharged,intercooled high performing version having an output for a 6 cylinder version of 2000 bhp at 520 rpm. Really an advanced modern engine I believe introduced in 1944.
I  do not think this last version of the MAN engine was used in a VIIC as 2000 bhp at 520 rpm would require  quite a few alterations in both the Emotors, shafting and propellers etc.
However I guess the engine was developed for the new "Electroboats" class XXI all equipped with MAN 6 cylinder M6V 40/46 KBB being the last type of the WW2 MAN submarine engine.
Below I have a picture explaining why I assume your picture is from a XXI boat. The people are standing on a footstep attached to the engine (on the GW engine is a similar footstep which can be folded in) which fooled me to believe it was a smaller boat. Even if the airduct from the turbocharger and intercooler is not rounded as on the picture of the MAN M6V 40/46 KBB, I believe there are so many components similar to a MAN engine which justifies my conclusion the engine is a MAN M6V 40/46 KBB in a XXI boat of which I have no knowledge.
Tore

[tore]

Don.
Further to my todays post. Do not to use the photo of the MAN 6V 40/46 KBB,  if not any better, may be my photo of the  IXC 9 cylinder MAN M9V 40/46 as I can`t find a good photo of a 6 cylinder.
Tore

[Capt Kremin]

Hi tore, Don et al
 
Is this photo any good to you it is from the MAN museum where they have/had this engine on display,
 
Regards
Jon

[tore]

Jon.
I guess it shall work, it is a 6 cylinder turbocharged MAN, it is not intercooled and has even a VIIC model at the step. Funny crankcasecovers though, I am not sure if they are expansion vents for possible crankcase explosions or not.
Tore

[Don Prince]

Hello Mr. Tore and Jon,


I had that photo of the MAN Diesel, but I didn't notice the model U-Boat setting on the step...  Apparently Mr. Tore's eyesight is much better than mine...


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


Could you post the one photo with the crewman is shorts cranking the outer exhaust flap valve hand-wheels.  I believe the photo I had with the two crewmen cranking the inner exhaust flap valves in the back of the diesel room.


Was the crewman is shorts in a VII or a IX?


Regards,
Don_

[tore]

Hello Mr. Tore and Jon,


I had that photo of the MAN Diesel, but I didn't notice the model U-Boat setting on the step...  Apparently Mr. Tore's eyesight is much better than mine...

Regards,
Don_

Don.
That`s possibly because I am a 1929 model !
Tore

[tore]

Don.
Here is the photo, but remember it is most probably  type XXI boat and definitely not a VIIC. As I said I don`t think the intercooled MAN was ever used in a VIIC as the output max cont 2000 bhp against the VIICs 1400 bhp and max. cont revs 520 against VIICs 480 rpm would be too much for the existing shafting and E-motors of the VIICs. Moreover the torsional vibrations would probably be different.
 As to the inner or outer flapvalves I cannot comment because I don`t know the XXI, but I guess they are the same valves on both photos  only that the photo of the man in shorts is taken from aft towards the bow and the photo of the two men  is taken from forward towards aft. You can see that on the intercooler of the latter.
Tore

[Don Prince]

Hello Mr. Tore,


You have discussed a normal dive with an angle of about 7 - 8 degrees...  What are the differences if this is an ALARM - Crash dive?


Regards,
Don_

[tore]

Don.
The German alarm dive is a typical wartime manoeuvre and required a highly trained crew to perform, it is not a matter of divingangle alone. There are several ways to carry out crashdives, some potentially dangerous like preflooding the ballasttanks and excessive diving angles. Generally you may say a crashdive required a combination of speed (hydroplanes lifts) and flooding. Crash dives are performed under roughly 3 major circumstances 1. Dieselcruising on the surface, when you have the speed ( hydroplane efficiency), as well as the Q filled and the submarine is prepared for diving. 2. After surfacing and during exhaustblowing of ballast tanks, that`s why some COs preferred to use one of the diesels for propulsion to have a surfacespeed rather than an e- motor having much lower output. 3. At the surface, charging the batteries, some CO preferred to have a dieselpropulsion as well. Under all conditions the submarine is prepared for crashdives in hostile waters and possibilities of suprise attacks. The schnorchelling made these crashdives a bit easier.
Basically the first stage, from a divingangle point of view, is the normal 7-8 degrees as you want to have sufficient water above your propellers and hydroplanes all the time. As soon as you are below the surface and you want to go deep, you start  blowing Q at 10 meters as previously described.  At approximately 20 meters controlroom reading you turn the bow down between 8 and max. 30 degrees depending upon circumstances, watching the bow depth carefully, at 25 degrees bow down it is some 30 meters wc pressure difference between bow and stern, before eventually flatten out. See my sketch below.
Tore

[Don Prince]

Hello Mr. Tore,


Excellent...  I will add this to my Skizzenbuch and I believe it's about finished.  I can't thank you enough for the information and the education...


Kind regards,
Don_


PS
Credits for my book...


I know Mr. Tore's full name, City?, Norway, Rank and dates from & to served on Haura (ex U-995)
I know Maciek's full name, Warsaw,Poland, I called him the Professor because he really knows the German documentation and he translated most that's available.
I know Simon's first name only.  City?, New Zealand, I used a few of his excellent drawings. He is quite talented and has an eye for details.

[tore]

Don.
For the sake of order, when U-995 served in the Royal Norwegian Navy she was named KNM (Royal Norwegian Navy) Kaura having pennant no S 309. I live in Bærum next to Oslo. Good luck with your skizzenbuch.
Tore

[NZSnowman]

Hello Mr. Tore,


Excellent...  I will add this to my Skizzenbuch and I believe it's about finished.  I can't thank you enough for the information and the education...


Kind regards,
Don_


PS
Credits for my book...


I know Mr. Tore's full name, City?, Norway, Rank and dates from & to served on Haura (ex U-995)
I know Maciek's full name, Warsaw,Poland, I called him the Professor because he really knows the German documentation and he translated most that's available.
I know Simon's first name only.  City?, New Zealand, I used a few of his excellent drawings. He is quite talented and has an eye for details.

Hi Don

Simon J Morris, Castle Hill, New Zealand

Don, I live in a small village in the mountain call Castle Hill (only about 20 people), Christchurch (about 1½ hours drive away) is my nearest small city (Pop. 350,000).

[Don Prince]

Hello Mr Tore,


Past 1497, Page 140 "The gate valves and drain valves are operated from the deck casing"....


To me, it looks like the gate valves hand-wheels are located inside the pressure hull and the drain valves for the common duct must be opened from the out side under the deck casing?


Am I all wet again?


Regards,
Don_

[tore]

Don.
I guess you are referring to plate 16 and understand your confusion. The drawing is a bit misleading as some valves like the emergency shutoff valves c are drawn correctly having the valvespindle through the pressure hull indicated by a double line crossing the spindle and the gatevalve spindles d not crossed by a double line, indicating to be operated outside the pressurehull eg. from the casingdeck, I guess  by a T bar, thus no wheel. However the confusion is, the Kingstons and the main ventvalves for some reasons are not marked with a double line even if they are operated from inside the pressurehull. If you look at some of Simons excellent drawings shown below it clearly indicates how the system works. I believe the valve wheels are removed and the valve spindles are operated by a T bar as  mentioned and can be seen on many photos.
Tore

[tore]

Don.
Although you are about finished with your Skizzenbuch I`ll mention a small but important detail of your description of Plate 8 page 58.  When fuelling, the seawatercompensating system is open as well, the selector valve is in fueltank configuration eg. direct connected to the fuel/ballasttanks 2 and 4. When fuelling deliverypressure is exceeding the compensating pressure the compensatingwater is forced overboard via the header tank. It is important to prevent any fuel to enter the system ( danger of oilslick) thus the compensating waterpipe in the fueltanks is at the lowest point in the tanks approximately 10 cm. lower than the the testpipe to ensure the man checking the testcock has time to shut of the fuelsupply. Due to this it is always some residue compensatingwater left in the tanks.
Tore   

[Don Prince]

Thank you Mr. Tore...


I have added a graphic and a paragraph to Skizzenbuch.


Regards,
Don_

[tore]

Don.
Good. As to the high voltage general electric scheme  I got the advice to have it scanned, unfortunately in the rural remote area of my farm I have no possibilities of getting that done. When moving back to civilisation some time in October I`ll  try to have it done.
Tore

[Don Prince]

Great news Mr. Tore about scanning the document...  That is definitely one item I would like to place in the Wallet folder in the back of my personal Skizzenbuch.


I believe scanning the High Voltage General Schematic will save something that is most-likely a one of a kind document; something like preserving a Rembrandt, or a Picasso (I may be exaggerating some what), but I'm glad to see that happen...


Regards,
Don_

[tore]

Don-
Well, comparing a shabby 2nd. copy of a bad blueprint with an original Rembrandt is may be a bit far fetched. Anyhow it can`t be better than my bad drawing. But seriously these were the kind of drawings we had to use to keep the boat running at that time. If worst come to the worst we might use the good old mail, however it is my intention to donate same to the Naval Museum where the rest of my books,notes and drawings are.
Tore

[tore]

Museum U 995 schnorchel.
We have many times mentioned the differences between the original U 995 and the museumexecution. The schnorchel is one of the differences. In fact U 995 did never operated as a schnorchel boat during WW2. She was still at the yard in Trondheim , Norway installing the schnorchel May 1945. The original schnorcheltype had the ringfloat type of air intakevalve and operated with this type of schnorchel all the time under Norwegian flag. For some reasons the museum U-995 has got an incomplete execution of the hinged type float mast.
Tore

[Don Prince]

Hello Mr. Tore,


a few questions about Schnorcheling...  (ah snorkeling)?


U-995...
Q1.  What was the top speed while schnorcheling?
Q2.  Could the attach periscope be up at that speed?
Q3.  Were they not completely blind at top speed?  (I would not believe they could listen for enemy or targets while the Diesel Engine/s were running submerged).
Q4.  Could they run both diesel engines while Schnorcheling?
Q5.  If schnorcheling and attached by aircraft, did the schnorcheling mast up present any problems while diving for safety;  depth limitations or maneuvering issues with the mast up?
Q6.  Could they lower the mast while diving or while submerged?


We need some more activity on this thread... I may update my Skizzenbuch with more great information from Mr. Tore...


Regards,
Don_

[tore]

Don-
Snorting.
Schnorcheling is the German word for a Dutch system allthough known for many years before the dutch invention. In RN English the word used was snorting.
Q 1. The theoretical construction strength of a VIIC snort mast could take max. 6,5 knots I believe.
Q 2. We used the periscope while snorting.
Q 3. We were not completely blind, but one of the big disadvantages while snorting, regardless the speed,  was the diesel engine noise and you could not use the passive sonar.
Q 4. You could run both diesels while snorting but limiting factors like underpressure, backpressure and speed would not give you much advantages of doing so.
Q 5. You could could go deeper while snorting shutting down the diesel immediately. and you would lower the mast while doing so.
Q 6. We mostly raised and lowered the mast while submerged, but you could do this surfaced as well.

A remark concerning my personal experience. We had an event before my submarine training course in UK, may be you recall the disaster of HMS Affray a British A class submarine. The training class 2 years ahead of mine was on board on a final snorting training in the English channel when she disappeared with all hands lost including the whole trainingclass, totalling 75 men. She was eventually found with the snortmast raised but broken. The discussion of the reason for the disaster was at my time still going on and in spite of the German snorting instructions I was a bit cautious as to pushing limits while snorting. One of the alternative snort propulsion, direct dieseldrive, we found a bit difficult to practise as the boat was no easy to handle, so we preferred electric propulsion running one diesel and generator as battery charger.
 However as to HMS Affray I guess the conclusion was battery explosion and the broken snortmast was a secondary  damage. 
Tore

[SnakeDoc]

Don,

some interesting information about German Schnorchel (i.e. the operating modes) you can find in this instruction:
http://www.ubootwaffe.pl/images/okrety/instrukcje/chrapy/preliminary_snorkel_description1.jpg
http://www.ubootwaffe.pl/images/okrety/instrukcje/chrapy/preliminary_snorkel_description2.jpg
http://www.ubootwaffe.pl/images/okrety/instrukcje/chrapy/preliminary_snorkel_description3.jpg

Other useful information can be found in these operational orders:
http://uboatarchive.net/BDUOrder1.htm
http://uboatarchive.net/BDUOrder2.htm

--
Regards
Maciek

[Don Prince]

Hello Mr. Tore and Maciek,


Thank you all for the information on the Schnorchel (I learned how to spell in right this time)...  I'll have to go back and correct the spelling in my Schizzenbuch!


Regards,
Don_

[SnakeDoc]

Hi Gentlemen,

regarding to Schnorchel, I have attached the Schnorchel Befehlsprache - list of commands used when Schnorcheling.
Some time ago, I have written article about Schnorchel in Ubootwaffe:
http://www.ubootwaffe.pl/okrety/wyposazenie/chrapy
It is in Polish (I do not have time to translate it), but maybe you will find interesting drawings or photos, and if you will get
interested in some part, I will be happy to translate or explain it.

--
Regards
Maciek

[Don Prince]

Hi Maciek,


Great articale...  Not a problem with the translation; Google Chrome asks if you want this page translated and does so...


Regards,
Don_

[Don Prince]

Gentlemen,


Does this photo look like the BOLD decoy launcher which is located in the Aft Torpedo room...  I believe the long red handle is to unlock the inner door and it swings open on the hinge.  The bolt decoy in loaded into the tube and the inner door is closed and locked.  Then the red hand-wheel opens the outer door and the bolt decoy is launched with HP air.  The only thing I don't see is the triggering device.  Am I close to correct?


Regards,
Don_

[tore]

Don.
It is indeed a decoylauncher which the Germans called a Pillenwerfer. The device did not have much of a trigger but rather a handwheel, the blue coloured wheel on your photo, admitting air behind a launchingpiston inside the tube. It is an interlock preventing the outer cover to be opened unless the inner cover is shut. The pipeconnection on the top is the launch airconnection, while the lower small pipe is the drain. Otherwise you are pretty much correct in your assumptions. The Pillenwerfer was used for many purposes like launching canisters filled with magnesium pellets which, when in contact with the seawater produced bubbles giving a sonar echo resembling a submarine. In peacetime we very often used small rockets indicating a torpedo launch during exercises. It could of course be used for launching distres-signals as well.
Tore

[SnakeDoc]

Hi Gentlemen,

my small addition to Tore's info:

external photos of the Bold ejector: http://models.rokket.biz/index.php?topic=1150.msg14860#msg14860
drawings: http://u-historia.com/uhistoria/tecnico/visitaguiada/lanzasenyuelos/lanzasenyuelos.htm

Many pieces of info you can find on the uboatarchive.net website, searching the term "S.B.T." (Submarine
Bubble Target).

--
Regards
Maciek

[tore]

Don.
Trimming pump/trimcontroller.
I just happen to check you explanation of the system on page 30 in your Skizzenbook and believe you should include the trim flowmeter in your explanation. The reason is that when the pumpman operated the pump and the trimcontroller his eyes were fixed on the flowmeter in order to compensate the correct amount which some time could be within narrow limits. F.inst. as I have mentioned before, prior to the order "Diving station" the pumpman got the order from the officer on watch: pump 400 liters from aft to forward as this was by experience the exact amount needed to compensate the movement of the crew for such an order.
The trim flowmeter is correctly marked on the sketch by the green arrow.
Tore

[Don Prince]

Thank you again Mr. Tore,


I have added the information to page 30.  Usually over the weekend, I update the main Skizzenbuch PDF file and copy it to dropbox and you have access to any updates. 


I just got a response to an email to the U-Boote Museum in Cuxhaven, Germany, and they have a manual that is a treasure trove of information on the switchboards and e-motors.  With a great deal of help from Maciek, I will most likely have to re-write much of the switchboard and e-motor section.


Regards,
Don_

[tore]

Don.
Skizzenbuch fueloil supply pipe.
On page 67 you show a fuelsupply scheme of the fuelsupply from the daytank/ settlingtank to the engine driven fuel supplypump. This might be a bit confusing for an ordinary VIIC as the system shows a MAN engine configuration having the enginedriven supply pump in the aft end of the engine. The most common system is that of the GW engine having the fuel supply pump and filters up front of the engine. The picture below shows the GW system with cocks, filters and pump. After the double filters the supply pipe goes to a knifefilter (with drain to the dirty fueltank) behind the HP fuelpumps ( on top of the camshaft casing) and then to the common supply pipe to the HP fuelpumps.
Tore

[Don Prince]

Thank you Mr. Tore,


I updated Skizzenbuch and uploaded the latest PDF file to dropbox...


Regards,
Don_

[tore]

Don.
Your Skizzenbuch page 40 give a description and a photo which might give a wrong understanding, further the plate 7 and plate 17 could give an impression that venting and blowing Q is done via two pipelines.
 Both systems are combined in one crossoverline between port and starboard Q tank. On starboard side you have the red wheel which is the main blowingvalve for both tanks and is not involved in the venting as your nomination on the photo :"air supply, ventvalve drive shaft".
 When the main blowingair valve is opened air is admitted to the common crossoverpipe and to both tanks via the hullvalves and both Q`s are blown..
 When venting, the master blowvalve is shut and the common portside ventvalve is open and vent the common crossoverpipe for both tanks into the boat via the common muffler.
Thus blowing both Q tanks is only done by the red handwheel on starboard side and venting both Q's is only done on the port side by the lower T handle ventvalve to the muffler.
Below is a sketch trying to explain my remark.
Tore

[Don Prince]

Hello Mr. Tore,


I don't know if you have the current version of Skizzenbuch with 322 pages.  I believe we covered the issue of the Q tanks and there was an adder page 43 in the latest version.  However, If page 43 does not look good, then I will definitely go and replace it.  Can you download the latest version and let me know if you see any problems with page 43?


Skizzenbuch has started to increase in size; which is a good thing because I'm getting really good information.  Just Today, I got a response from the Uboote Museum in Cuxhaven Germany and they are going to copy an Electrical Engineering Manual with supporting drawings.  This is something that Maciek and I have been searching for in the past several years.  I can see there will be easily a dozen or more added pages.


Regards,
Don_

[tore]

Don.
Sorry I missed your latest version of the Skizzenbuch where you have the correct system of the Q. A minor remark is that you have marked the handles for the diff. manometer cocks as cut off valves may be you should add " for the diff manometer". I`ll start checking the latest version of the Skizzenbuch as from now. It is quite a comprehensive work to get everything into such a book and I guess you shall end up with a few extra pages before it is finished.
Good to hear you are getting along with your Electrical Engineering Manual and supporting drawings. Kindly advice if my high Voltage scheme is still needed when I am back to civilization in October.
Tore

[Don Prince]

Thank You Mr. Tore,


I corrected the photo labeling on page 44 and updated Skizzenbuch...


Regards,
Don_

[tore]

Don.
I hope I have the latest edition of your Skizzenbuch and am referring to page 157. On your image of the outer and inner main exhaustvalves it looks as you have mixed the inner valve with the outer. The inner valve is the aftmost red wheel operating a flapvalve being fully open when the relevant diesel is blowing the ballasttanks. The outer flapvalve just before the exhaust silencer is used for regulating the exhaust backpressure for blowing.
 The inner valve has a double turning shaft one acting as a fulcrum for the flapvalve, the other as a shaft ending in a square outside the gearcasing. On this square you can put a ratchet bar for grinding the valvedisc against its seat by hand. Very much the same way as the outer exhaustvalve except the latter in driven by the pneumatic motor. See image below.
Tore

[Don Prince]

Hello Mr. Tore,


I am in the process of correcting page 157...  When the engine room engineer is adjusting the Exhaust Silencer flap valve to establish the correct blowing pressure of 1.5 atm is he using the pressure gauge mounted on the back bulkhead (barely visible)?  What is the gauge ahead of it (most prominent in the photo) used for?


Thanks for picking out this error on my part.  I guess I was fixated on the pressure gauge in the center of the photo...


Regards,
Don_

[tore]

Don.
I don`t think so Don, this manometer is marked for the normal LP air pressure and I guess it is used for the pneumatic/air system of the main clutches. As far as I remember, the exhaustpressure would be checked by the manometer in the instrument panel up front of the engines. I am not sure if I understand you question referring to the most prominent gauge are you referring to the fuelmeter for the day/settlingtank?
Tore

[tore]

Don.
In your Skizzenbuch page 59 you are stating: "note the internal aux. luboil pump is not used to fill the fuel oiltanks". Under normal circumstances the fuelling station is able to furnish adequate fuellingpressure, however the ¨VIIC  systems are generally  quite diversified and able to handle a number of situations. F.inst. if you are fuelling from a source not able to supply adequate pressure to force out the compensatingwater you use the aux luboil pump. Likewise if you for some reason should empty the fuel in the fueltank without being able to use compensatingwater pressure f.inst during docking or maintenance, you might use the aux. luboilpump as seen on my two sketches below.
Tore

[Don Prince]

Hello again Mr. Tore,


I made the corrections to Page 157 and that location is in the 2nd third of the book (not a problem).  I had an issue with "MS Word" crashing and corrupting my file, so I had to break up Skizzenbuch into 3 parts.  I also corrected page 59 and added your excellent drawing, but that involved deleting a print and moving things around to get everything in the 1st third of the book's 108 pages.  Pages 57 through 69 were moved or changed.  However, I believe the changes make everything flow much better as far as information and presentation goes.


I uploaded the latest version of Skizzenbuch to dropbox with all your changes to date...


I really appreciate all your extra effort in making Skizzenbuch a good source of information on the type VIIC U-Boat.  At 322 pages, I have to go back and read what I had written (I think sometimes I have a senior moment!)....


Kind regards,
Don_

[tore]

Don.
You idea of a Skizzenbuch is great but ambicious as it is almost impossible to incorporate every thing. To day I am referring to page 76 and your description of the saddle tanks fuel configuration plate 16. May be a short explanation of the system would be helpful. As mentioned before plate 16 is a bit unclear with regard to which valves are inside and outside the pressurehull. As a rule the valves operated inside the pressurehull have a double line crossing the valvespindle. However the Kingstons marked on plate 16 have not.
The venting system of the saddletanks has a special arrangement as the tanks a stretched over a long area of the submarine. As the tanks have a common main vent appr. midships this create a problem particulary when diving at a steep angle down as air shall be trapped in the aftermost part of saddletank 2 port and stb. ,see my sketch below. To overcome this is a small crossover residue ventpipe having a common ventvalve in the aft part of the tank. The vent can be operated both from the controlroom and the engine room. Like the common main ventpipe for the saddletanks the residue ventpipe has individual gatevalves to be shut in fuelconfiguration. These valves are, like the gatevalves in the mainventpipe, operated from the casingdeck outside the pressure hull.
The gatevalve on the photo you are assuming is the ventpipe gatevalve D1 for the residue venting, is the port forward engineroom bulkhead valve for the shipventilationsystem and has nothing to do with the saddletank residueventing.
Tore

[Don Prince]

Hello Mr. Tore,


I know I can't put everything in Skizzenbuch.  However, my idea is to create a single book that gives the reader (now me!) a good understanding of the design and functionality of the Type VIIC U-Boat.  I am especially grateful to you because I don't believe there is anyone else left with the knowledge you have on the Type VIIC U-Boat.


I have updated Skizzenbuch with your latest suggestions, and posted the latest Skizzenbuck into dropbox...


Regards,
Don_


PS:  I don't believe the U-Boote-Museum has the large ship print that you have because that came from the builder.  Their books are of the Kriegsmarine training variety...

[tore]

Don.
I have just had a quick glance on your latest edition of your Skizzenbuch and have a few minor remarks. On page 40 you have still a photo marked as valves controlling the Q tanks.The starboard main blowingvalve is marked as ventvalve drive shaft, as this is wrong I suggest you name it the common main blowing valve for Q. On the photo of the port controllingvalves for Q is the main vent valve marked as valve in the line to the muffler below, which is correct, but I believe it would be easier to understand if same is named as the common main vent valve for Q tanks.
On page 157 the handwheels for the inner and outer main (Group) exhaustvalves are interchanged. The aft wheels marked as external flapvalves are the internal, and the forwards marked as internal flapvalves are the outer flapvalves before the silencers . I guess the confusion is due to my photo where I for some reason have erroneously have marked the inner flapvave gearsegment as Casing for EXTERNAL EXHAUST FLAPVALVE SHUTTING GEAR SEGMENT, it should be internal, please correct. Sorry
Tore

[Don Prince]

Hello Mr. Tore,


I corrected page 40 and 41 with your recommendations...  Thank you.


The right insert photo of the "Casing for the External exhaust flap valve gear segment" looks to be positioned near the aft engine room bulkhead, and you can see part of the pneumatic motor.  This looks to be correct to me???  Am I missing something?


Both the external and the internal exhaust flap valve are manually controlled by the hand-wheels which turns a shaft with a worm gear to drive a segment that opens or closes the exhaust flap valve.  Is this correct?


If so, then would this photo be OK?


Regards,
Don_

[Don Prince]

Hello Mr. Tore'


After reviewing your diagram of the flap valves, I believe there is a gear in the casing and not a segment.  I think that part needs to be changed,,,  What do you thing?


Regards,
Don_

[Don Prince]

How about this....  Don_

[tore]

Don.
The image correction 4 you are referring to is erroneously marked external exhaustflapvalve by me and is the internal main (Group) exhaustvalve operated by the red handwheel. The handwheel turns a spindle with wormgear engaging a gearsegment attached to a hollow fulcrumshaft  , (yellow on my sketch) connected to the rotation center point of the the flapvalve disc having a geared rim. The shaft ends in a valveindicator (pointer) forward outside the gearsegment casing, showing the position of the valvedisc. Inside the fulcrum shaft is a (black) shaft with wormgear engaging the valvedisc gear rim  for turning (grinding) the valvedisc against its seating. The shaft is protruding outside on the aft of the valvecasing and ends in a square for a ratchet bar for moving (grinding) the valve disc. So the inner main exhaustvalve is ground by hand. The outer main exhaustvalve (before the silencer) has a similar arrangement but the shutting and opening of the valve is done by the wheels forward of the inner mainvalve handwheels. The operation transmission to these valves are done by bevelgears and rods outside the pressurehull and the grinding is done by the pneumatic motors driving rods and bevelgears turning the valvedisc in the valvecasing outside the pressurehull. Basically the same way as the inner valves but pneumatically driven instead of the hand ratchet rod. Thus the aft handwheels are for the inner valves, the forward handwheels are for the outer.
Tore

[Don Prince]

Hello Mr. Tore,


Does this drawing look OK?


Don_

[tore]

Don.
This looks excellent except the arrow to what you call internal flapvalve gear segment point to the pneumatic motor for the drive of the grinding rods for the main outer exhaustvalve disc.  As the combination of  shutting and grinding of the valve makes it difficult to understand I made a sketch below showing the working principle of the mechanism for the inner valve.
Tore

[Don Prince]

Hello Mr. Tore,


I made the arrow longer so it is touching the segment casing...  Uploaded corrections to dropbox...  The location of the flap valves internal and external is a bit confusion because the external exhaust flap valve casing is outside the pressure hull and farther back. However, it's the drive shafts that place the controls farther forward ahead of the internal exhaust flap valve controls in the diesel room ceiling.


I liked the last diagram you posted showing the internal exhaust flap valve drive segment...


Regards,
Don_

[tore]

Don.
I just checked you to days corrected edition of the Skizzenbuch in the dropbox. I still think you should lengthen the arrow for the gearsegment of the inner main exhaust valve pointing at the pneumatic motor for grinding outer main exhaustvalve.
Tore

[Don Prince]

Hello Mr. Tore,


I did take your suggestion and lengthened the arrow  However, I posted the old photo back into Skizzenbuch.  I posted the correct photo and updated Skizzenbuch in dropbox.  below is the photo that is now in Skizzenbuch... 


Regards,
Don_

[tore]

Don.
That`s it
Tore

[tore]

May be we get a bit serious in the play of VIIC details. The other day I was looking into a cross section of MBT 3, suddenly this picture turn up in my head. Might be a new avatar?
Tore

[SnakeDoc]

May be we get a bit serious in the play of VIIC details. The other day I was looking into a cross section of MBT 3, suddenly this picture turn up in my head. Might be a new avatar?

Haha, Tore, great picture

--
Regards
Maciek

[tore]

Don.
All of a sudden I remember a manometer for the exhaustgaspressure in the exhaustgasmanifolds which could be used for adjusting the exhaustgas blowing pressure as well. It is placed on the forward stb. side of the housing for the Roots blower. The manometer shows the pressure in ATU (overpressure) and thus have scale from 0 to 1. I am not sure but may be it was installed in relation to the schnorchel installation. In addition, the engine exhaustmanifolds have a reliefvalve up front of the manifold. Particulary during schnorcheling these valves could lift, letting in an unpleasant dark exhaust into the engine room.
Tore

[tore]

Don.
Having looked through your Skizzenbuch I wonder why you have not included a main item as the schnorchel system. Introduced in August 1943 as a counter act to the allies air superiority it was an important conversion for the German uboats in 1944-1945. As we have discussed before you can`t include everything, but I guess this is an important detail of the submarine WW2 warfare which is worth while to include.
Tore

[Don Prince]

Hello Mr. Tore,


I am still working on the schnorchel addition and will update Skizzenbuck in a few days...


Regards,
Don_

[Don Prince]

Hello Mr. Tore,


Perhaps you can help me with this diagram...


1.  The hydraulic pressure oil cylinder has 150 and the greek letter theta?  What does that theta mean?
2,  How do they know the schnorchel mast is fully up or down?  Would that cause an increased pressure reading on the manometers so they know the mast is fully up down?
3.  Does the throttle switch control valve determine the direction of the piston drive? Mast Raise is high pressure oil and mast Lower is hydraulic oil back to the source inside the pressure hull.
4.  I believe things are reversed when lowering the mast.  Is that true?
5  Any other comments about the diagram?


Regards,
Don_

[tore]

Don.
1. This is the international letter for diameter in this case 150 mm.
2. It is an indicator up forw. port side in the control room see picture below.
3. Yes it is a handoperated switch connecting the "raise" side of the piston to the hydraulic pressure system and the "lower" side to the hydralic oilreturn see picture below.
4. Yes
5. The sketch is not showing the handle for lowering/ raising the mast, see my picture.

Tore

[tore]

Don.
Before we go into further details may be we should discuss the basic systems of the Schnorchel. I don't`know your knowledge of the systems, so have me excused for going into the some items which might be too obvious to you.
 As a consequence of the great losses in 1943 due to allied air superiority, the germans had to do something to protect their Uboats and looked into a dutch system from before WW2  called the "sniffer" translated.  The system had to be adapted to the existing Uboats so they had to utilise the existing systems. Thus they had to make some compromises.
In the end of 1943 their system was ready to be installed in the frontline boats. The mast could not be telescopic that would require major changes, so they made a hinged type of schnorchel which could be folded down in the casing ( for VII Cs port side of the forward conningtower). The system utilised the existing exhaust blowingsystem for the ballasttanks using the same pipes up to the distribution chest outside the pressurehull  starboard side of the forward conningtower casing. Right before the chest it is a branch off to the schnorchelmast. In order to pass the distribution chest they had to let the pipe to the schnorchelmast go above the casingdeck ending in a schnorchel shut off exhaustvalve before the pipe goes under the deck and connects to the schnorchelmast.
The air intake ( for the first generation of the system) utilise the existing outboard ventilation airduct in the casing outside the pressure hull. The air enters the schnorchel mast via a top floatshutting valve being either  ringfloated or  hinged floated controlled.
Half way up at the conning tower appr. at the spray deflector the mast air pipe engages a fixed pipe on the conningtower via a rubber flange. This pipe goes to a drainvalve operated from the control room just before it enters the ventilation intakevalve inside the conning tower casing. Then it follows the ventilation duct still outside the pressurehull almost to the pressurehull inlet valve and have a cross over to the dieselair duct. The airinlet follows the dieselair hullvalve into the engine room. The reason for this arrangement was that in case of massive water intrusion, the ventilation fans could be destroyed whereas the large dieselair ducts ended near the bilges. Quite a few VII Cs had this arrangement.
This system was not quite satisfactorily and a modified new system was designed. The new system kept the arrangement for the exhaust, which is quite simple, but the air system was changed. The pipe on the conning tower was removed instead came a hollow schnorchel fulcrumshaft and the air was lead through this shaft and aft under the casing directly to the dieselair duct. One small detail though, it was not sufficient space for the bend leading the pipe aft so they had to make a hole in the casing to let the pipe turn aft outside the casing, hence it was easy to see which U boat had the new design, see my picture.
Puh! some long story, just ask if something is unclear may be I can answer !
Tore

[VIC20]

Hi, I'm still alive and still busy with my game. mostly working on graphics stuff and other non-simulation related things: https://www.youtube.com/watch?v=1IAL_24bfb4&list=UU03RMMpKkHkZVROUHFTWYVA

Don, the Skizzenbuch, any chance to get a copy of it?

[tore]

Mark.
Good to see you are still around. I can`t stop being amazed by the graphics. One thing struck me though, to me it seems like the anchorbay is a bit high up on the U 96.
Tore

[VIC20]

oh 


you mean the dent / hole for the anchor? It's on the same position as on the drawings I've used hmmm. Will look into it when I finish the model.

[tore]

Mark.
Yes it looks a bit strange to me.
Tore

[VIC20]

Yes you are right. It's a comparable tricky part I hope I can fix it without running into new problems.


*searches for his time machine to travel back and change original pre-wwii type vii plans*

[Don Prince]

Hello All,


The type VIIB and early VIIC had the standard bow.  Then the Atlantic bow was introduced and that widened and raised the bow.  I have the German edition or Rossler's book Geschichte des deutschen U-Bootbaus and the included fold out schematics show the obvious difference.


Regards,
Don-

[Don Prince]

Hello Mr. Tore,


I just posted the latest version of Slizzenbuch into dropbox with our first attempt at including the Schnorchel,,,  I typed schnorchel so many times that I'm even spelling it your way.


Regards,
Don_

[tore]

Don.
Not bad, your are learning details of the VIICs and you are picking up the German language at the same time .  I`ll have a look and revert later my time today.
Tore

[VIC20]

The type VIIB and early VIIC had the standard bow.  Then the Atlantic bow was introduced and that widened and raised the bow.  I have the German edition or Rossler's book Geschichte des deutschen U-Bootbaus and the included fold out schematics show the obvious difference.

I think I scanned the fold out schematics from those 2 Rössler books (and the plan on page 166/167 of book #1) to build the model - something must have gone wrong.

[tore]

Don.
On page 311 you have photos of the old and new version of the schnorchel  piping system. As you shall see from my text the old exhaust system was kept and only air inlet was changed on the new system. So I wondered why you had marked the airpipe on the tower and the protruding airbend out of the casing exhaust. Then I realized that I had posted  a wrong picture which should have been deleted as the bend and pipe were marked wrongly exhaust. Sorry about that but sometimes when you handle a lot of pictures it is hard to see such details in the process of posting.
On the system drawing page 312 you have copied my sketch of the old air inlet system (blue) correctly apart from a small branch off to the ventilation hullvalve. As mentioned in the text, the ventilation airduct hullvalve in schnorcheling mode is shut to prevent waterintrusion into the ventilationfan thus all the air goes into the diesel airduct/hullvalve.
Tore

[Don Prince]

Hi Mark,


The book page 166/167 is the (1940) General plan with the standard bow.  However, the separate large fold out plans in the back of the book Tafel IV and Tafel V are for the VIIC (1944) General Plan and this is the Atlantic bow.  My book set came with separate large folded prints just placed in the back of the book Volume (Band) 1, Tafel I through IX - and Volume (Band 2), Tafel X, XI, XII, XIII, XIV, XV, XVI, and XVIII. There was no XVII??


Regards,
Don_

[VIC20]

There was no XVII??

This is Tafel XVII:

[Don Prince]

Hi Mark,


I looked again and I do have XVII... Apparently I didn't check the back of XVI when I was going through the fold out sheets.


Regards,
Don.

[Don Prince]

Hello Mr. Tore,


I believe I made all the corrections to the Schnorchel section of Skizzenbuch and uploaded to dropbox.  I also cleaned up the first few pages wording, and added photos of U-995's schnorchel installation and the mast guide and holding mechanism.  When I was first doing the schnorchel write up, I was wondering what held the mast in place other than water friction when the U-Boat was moving forward.  Then when I was looking at the photos of U-995, I noticed a raised section at the inside front of the guides and a vertical shaft in back of the guide metal housing. That led me to the conclusion that the guides spread apart, then clamped around the mast under spring torsion when it was at 90 degrees...


Regards,
Don_

[Don Prince]

Hi Mark,


Thanks for your effort...  By the way, I have Rossler's book in English (only a single thick book with small print size), and the drawings are bound in the back of the book and take 2 pages.  However, there are only 12 schematic.


Regards,
Don_

[tore]

Don.
I checked to days Skizzenbuch on the Schnorchel which as far as the airpipe goes is OK.
 I am not sure of your description on the homing of the Schnorchel though. The U 995 has many modification from the original and the schnorchel is a major one. The mast air valve is a hingefloat, original is a ringfloat, the schnorchel lockingpin drive rod from the control room is removed, the raising and lowering system is partly removed just to mention a few items. The schnorchel installation make use of the existing hydraulic system with a branch off and shutting valves from the periscope pipes. The mast is secured in a downright position by a locking clamp operated from inside the pressurehull portside up near the CO cabin. Likewise the mast is secured in the homing guide at the towercasing. This lockingpin is operated by a wheel connected to rods from the controlroom port side up. The transmissionrod have different positions at the various boats, some goes inside the towercasing, some partly inside or in an outside protector casing but all rodversions  protrude outside the casing at the spraydeflector  before they are engaging the locking device. I have tried to incorporate most of this in the image below the schematic sketches made by me are my assumptions which might deviate from the real design.
Tore

[tore]

Mark and Don.
Atlantic bow. Simon has done some research on this and his conclusion is that the Atlantic bow start to raise at frame 104 and reach the full height at frame 111. The anchorbay is located between frame 103 and 106 so I don`t believe this has a significant visual effect on the position of the anchorbay in relation to the casingdeck.
Tore

[VIC20]

Somehow the whole anchor bay went to the wrong position and it is a bit smaller than the original. No idea how that could happen.
Tore is Mr. Eagle-Eye.


 

[tore]

Mark.
This seems to be much better. The anchor bay was not a problem only to you, Revell put it quite a bit too far aft on their 1:72 buildingkit for VIIC/41
Tore

[VIC20]

fixed?


upper = repaired, lower = before

[tore]

Mark.
Excellent. I like your two bow floodgates in the waterline on the starboard side and hope you have 3 on the port.
Tore

[VIC20]

unfortunately not    the smaller holes are just painted and the texture is identical on both sides. I can try to add a 3rd one when the model is finalized.


I've also fixed the painting of the anchor bay to fit to the water line - I guess this is correct?

[VIC20]

Ok, I've made those holes real ones and added a 3rd one on the other side…

[tore]

Mark.
Very good. May be the flood gates are a bit low in relation to the anchorbay and waterline. They are a few cm above the waterline of a VIIC/41 anyhow as can be seen on my image below.
Tore