Author Topic: Tores mailbox VIIC and VIIC/41 operation and technical details (Read 665866 times)

Don Prince · « **Reply #3000 on:** 30 Apr , 2016, 11:13 »

Mr. Tore and Maciek,

Thank you all for the info... Due to the placement of the aft torpedo in the deck casing; I highly doubt the aft torpedo could be launched during a surface attack on the Type VII A.

Regards,
Don_

SnakeDoc · « **Reply #3001 on:** 02 May , 2016, 01:04 »

Hi Don,

Quote from: Don Prince on 30 Apr , 2016, 11:13

Due to the placement of the aft torpedo in the deck casing; I highly doubt the aft torpedo could be launched during a surface attack on the Type VII A.

I guess you are right. However, one should review available Schussmeldungen to tell for sure.

--
Regards
Maciek

Don Prince · « **Reply #3002 on:** 03 May , 2016, 17:05 »

Hi Maciek,

OK... By the way you will need to re-upload your image as a jpeg to get the image right. I had to do that to get my image corrected...

Regards,
Don_

tore · « **Reply #3003 on:** 04 May , 2016, 12:02 »

From time to time discussions pops up on the two "blisters" which are seen on both sides of the VIICs bow approximately between frame 77-78 or about the same location as the capstan. I have seen many fantasic speculations particulary related to the torpedo launching system. The " blisters" can be seen on the VIIBs as well. I have studied the arrangement and can not say my conclusion is 100 correct, but I assume the "blisters are the venting/ flooding gates for the very narrow difficult freeflood space between the pressurehull and the casing in this area. The flood/venting gates have a streamelined cover having outlet towards aft which creates a ejector effect when sailing ahead which facilitates efficient draining.
On my image below I have tried to explain my idea. On several drawings I have seen MBT 5 is including this void space, however on the original drawings MBT 5 has a bulkhead shutting off the space between frame 80 and the weldingseam for the fwd dome of the pressure hull. This bulkhead goes from the top to the centerline for the lower torpedotubes and from there slopes down to the aft floodgates at frame 76. Hence the void space between the pressurehull and the casing is a freeflood area which has to be drained (and flooded). The area is marked blue on my images. I have not yet seen modelbuilders considering this detail on the Revell kit.
Tore

Don Prince · « **Reply #3004 on:** 04 May , 2016, 13:45 »

Hello Mr. Tore,

I like the new Avatar you have chosen for your online image... I believe the Revell Type VII C U-Boat model does have the ejection ports you are describing. At least according to the image I was able to pull from the internet (Ejection Port image), and perhaps a bit too low. My OTW 1/32 model had the ports in the fiberglass hull which called for them to be cut out (Ejection Port 2 image). It took weeks to cut out all those holes in the fiberglass hull and seal them with epoxy glue so water would not wick up the fibers and ruin the finish...

Note the Revell model has an attachment between the fairing and the Fwd hydroplane, and the OTW model does not.

Regards,
Don_

tore · « **Reply #3005 on:** 04 May , 2016, 14:29 »

Don.
Yes for sure all the Revell kits have the blisters, may be a bit too small, what I ment is up till now I haven`t seen somebody drilled a hole for the outlet of the blister. I took the opertunity to make a new avatar while the site was down I am happy you liked it, it`s more a navystyle.Unfortunately quite a few images disapeared I talked to Wink about it but unfortunately he can`t recovered same but mentioned possibly to make a gallery if I could find back all the hundreds I made I am glad you downloaded what you needed for the Skizzenbook.
Tore

Don Prince · « **Reply #3006 on:** 04 May , 2016, 17:59 »

Hello Mr. Tore,

I still have all the images that I downloaded from the web site; plus many of the images with a series of changes until the final version in Skizzenbuch. In addition, I have 100's more form the net, Maciek, and you.

Regards,
Don_

tore · « **Reply #3007 on:** 04 May , 2016, 23:12 »

Don.
Good to hear I`ll revert if Wink consider to make a gallery.
Torel

tore · « **Reply #3008 on:** 09 May , 2016, 06:07 »

Don.
Got a message today, they are going to invest money to make a gallery within the site. I`ll guess we`ll get the info when same is ready. I think such a gallery would be of great interest and value to Uboat enthusiasts around the world. Allthough not yet fully aware how it would work I am looking forward to using it.
Tore

zhuravlik · « **Reply #3009 on:** 09 May , 2016, 09:10 »

Hallo zusammen,
i'm the idiot who photoshopped the Kya picture.
I'm converting Revell 05100 to KNM Kya and I needed that photo for reference and showing purpose.
Since I can't open those photos at page 169 and 170 of this thread( get error "bogus dqt index 10") would you please upload them again?

Thanks in advance,

Frank.

tore · « **Reply #3010 on:** 09 May , 2016, 10:26 »

Frank.
The conversion of KNM Kya startet about 1959 I left her 1956. Our submarine designer had just finished his work converting our old british U class submarines which did not had a schnorchel, hence modernising the U class involved a major rebuild not only a sailtower but a telescopic schnorchelmast as well. Prior to our major newbuildingprogramme 15 submarines in Germany we looked into the possibility of modernizing our 3 VIICs. Our chief designer Kaare Hegstad used pretty much his experience with the rebuilding of what we called the Ula class eg. the British U (V) class but choose to keep the hinged original german schnorchel which got a homing into the sail. A few faked photoshopped Kyas exist but only one was actually rebuild showed on the photo below.

tore · « **Reply #3011 on:** 09 May , 2016, 10:31 »

Frank.
A Photo of the KNM Kya in my time shows the old norwegian tower, three deckcontainers and she had of course three Kingstons on MBT 3 on both sides as all the VIICs.
Tore

zhuravlik · « **Reply #3012 on:** 09 May , 2016, 10:44 »

Te Deum laudamus!
Thank you very much, Mr Tore!!!

tore · « **Reply #3013 on:** 09 May , 2016, 11:21 »

For your interest, here is an image of one of our U class submarines with the new sailtower, including schnorchel. As you see it looks very much like the sailtower of KNM Kya, same designer.
Tore

zhuravlik · « **Reply #3014 on:** 10 May , 2016, 09:39 »

Mr. Tore, you are great, really!

I don't know how to manifest my extreme gratitude for your photo.
If you want to follow my WIP, please see:
http://forum.sub-driver.com/forum/builder-threads/2938-1-144-u-boat-type-viic-41-knm-kya-ex-u-926
I'm converting that Revell kit (05100) into a R/C model.

I begun to look for infos about this boat in March 2015 and, after a while found that double profile drawing with "K-klasse etter ombygging" writing below.
That convinced me the boat was really converted because Eberhart Rössler's U-boot (ISBN8840373810) is vague about this.
So i started the project, still lacking some infos but looking hard for them in the www.
Found several U-klasse sub photos and, recently even this one:
http://digitaltmuseum.no/021015532143/motiv-k-klasse-undervannsbat-knm-kya-s307-med-ombygget-bro-1960-skipssjef-kapteinloytnant-h-b-ellingsen
Some photos of this database are not available and, guess wich?
http://digitaltmuseum.no/search?rows=72&type_filter=Photograph&query=kya

Best regards,
Frank

tore · « **Reply #3015 on:** 10 May , 2016, 10:51 »

Frank.
I see there is another thread discussing the KNM Kya. Kya Ex U-926 was a VIIC and not a VIIC/41 class. But she had an Atlantic bow and was the first VIIC serving in the Norwegian Navy as from January 1949. We had three VIICs operating in the Norwegian Navy, one was a VIIC/41, KNM Kaura ex. U995. All three VIICs were modified before entering into the norwegian navy. One of the most visible change was changing the conningtower casing allthough many believe this was just the old 1939 tower, it was different as can be seen from my image below.
I served as the engineering officer (chief engineer) on both KNM Kaura ex. U-995 and KNM Kya ex. U-926. and knew ltn.cmdr. Bjørn Ellingsen very well.
Neither the U 995 nor the U 926 were fitted with the balkongeraet when in frontline serving in the norwegian navy, they were fitted later, anyhow after 1956.
Tore

zhuravlik · « **Reply #3016 on:** 10 May , 2016, 12:06 »

Mr. Tore,
Disregarding tower, wintergarden and hull thickness, wich are the main differences between VIIC and VIIC/41?
My intention is to build KNM Kya as the maximum evolution of a type VII i.e. with an idrodynamic sail and balkongerat.
Sort of european GUPPY program.

Best regards,
Frank

tore · « **Reply #3017 on:** 10 May , 2016, 13:09 »

Frank.
For a layman it is hard visually to see any outside differences between the two types VIIC and VIIC/41. The latter some tens of cms longer overall, mainly due to the atlantic bow which I guess is incorporated in the Revell Kit. The main difference is, as you say the stronger pressurehull and increased max. divingdepth. The stronger pressurehull increased the weight and as no change was made as to the mainengines some efforts was made to compensate this by removing and/or make lighter equipment whenever possible, but again no visible items. It might be that the max speed would be a fraction of a knot lower, but we did`t notice much difference. Some are of the opinion that the VIIC/41 had the new compass housing in front of the tower, generally not so, U 995 had the old rounded type although they have substituded this with the new type on the museums U-995, don`t use the museums U-995 as a reference as many details are unfortunately not correct.
The trouble to upload the images on this site is due to an upgrading they just had whereby all the images disappeared. They are busy with the problem, but I guess it`s difficult to resolve. As a substitute they are going to make some sort off a gallery they told me.
If you are in need of any images on my thread let me know and I get it for you.
Tore

zhuravlik · « **Reply #3018 on:** 11 May , 2016, 06:46 »

Mr. Tore, you are very kind.
So, the hull's mold lines are the same.
I would need every sail picture you have because i need to draw a plan for Kya's hydrodynamic sail.
You say that balcongerat was added after 1956. Was the boat still in frontline service?

Best regards, Frank.

tore · « **Reply #3019 on:** 11 May , 2016, 07:58 »

Frank.
The ex German VIICs finished in our navy as operational submarines 1960 and are since then was used for training and research. Unfortunately I don`t have any images of the new tower of Kya, but am aware of you needs and shall react if I get some.
As to the difference between the old standard VIIC bow and the Atlantic bow you may study the images below to check your buildingkit. Basicly the bow was raised a few cms and they put in a flare to the bow to improve the pitching behaviour in heavy sea. I guess there were several steps before the final solution.
Tore

Don Prince · « **Reply #3020 on:** 11 May , 2016, 15:04 »

Another view of the "Atlantic Bow" on U-995...

Regards,
Don_

tore · « **Reply #3021 on:** 11 May , 2016, 23:34 »

Frank.
I just checked the Revell 05100 kit which is a VIIC/41 so it shall fit your requirement very well. Only make sure the schnorchel has a ringfloat air inlet on top, not a hinge type as they put on the museums U-995.
Tore

tore · « **Reply #3022 on:** 12 May , 2016, 00:41 »

As next step in the developement of the Kya sail (or fin as we say it) I am posting an image of the testing of the tower on the class which relieved our K class (VIICs). The name of my old Kaura S 309 ex. 995 was transferred to the new submarine S 310 KNM Kaura developed in cooperation with the Germans and named the Kobben class ( Seal class). Below is the final solution, this class is later relieved by the Ula class, which now is planned to be relieved by another new class. Submarines warfare is expensive.
Tore

tore · « **Reply #3023 on:** 15 May , 2016, 03:12 »

One of my most read topics which disappeared during the last upgrading of the site was the effect on ballasttanks pressure related to the diving/surfacing angle of a VIIC. The standard correct divingangle should be about 7 degrees. An easy check on the correct divingangle would be as the top of the bridge wind deflector is at the watersurface the top of stern (in the RN called dutchess ass) should be at the surfacelevel as well. The relativly high pressuredifference between MBT 1 and 5 can easely be seen on my image below. At a moderate diving angle of 7 degrees there is a pressure difference between the floodgates of 0.7 kg/cm2. At a divingangle of 25 degrees you get a pressure differerence of 2 kg/cm2. Why is this important? Appart from the difference in stresses on the pressurehull, the requirement of blowing the ballasttanks changes, in case of an emergency blowing the MBT 5 would need 2 kg/cm2 higher airpressure (thus more air) to blow the same amount of water as on MBT1. If not adjusted the boat would get even a worse trim which might be dangerous.
When surfacing the ideal surface angle would be about 2 degrees by that the floodgates of MBT1 and 5 would be at the same level, 3.5 meters. This means when you start blowing the MBTs by exhaustgas the counterpressure in boths tanks are the same, the saddletanks counterpressures however are the lowest so you start blowing these tanks ,then you switch over to the MBT 1 and 5 until you get the deepest MBT3 at an acceptable counterpressure.
When blowing the ballasttanks the air/gas takes the easiest way eg. the lowest counterpressure thus you have to compensate for the pressuredifference otherwise you bagger up your trim. This is why you have all the individual adjustingvalves in the controlroom for each ballasttank, both for exhaust and air blowing.
Tore

Don Prince · « **Reply #3024 on:** 20 May , 2016, 18:48 »

Here is another one of Mr. Tore's drawings...
Regards,
Don_

tore · « **Reply #3025 on:** 21 May , 2016, 00:29 »

The sketch shown in Dons post indicates another problem with a submarine as well. Apart from the obvious disadvantages of trapped air in tanks which might leave treatcherous bubbletracks you have the dangerous and undesired effect called the free surface effect. As long as a tank ( or compartment) is either full or empty there is no such effect, however when partly full of liquid there is an unstable situation as the center of gravity moves back and forth as the pitch, heave, roll, surge, sway or yaw varies. The effect might create a larger problem for a submarine than a surface vessel. To avoid this, the submarine is designed to limit free surfaces as much as possible, hence you have watercompensated fueltanks and try to keep the ballasttanks either full or empty. The residue venting of MBT 2 helps to fill the tank completely and thus to get rid of the free surface effect as well.

Tore

Don Prince · « **Reply #3026 on:** 16 Jun , 2016, 19:04 »

Hello Mr. Tore and All,

I uploaded "Skizzenbuch 11 x 17 - M + Index.pdf" to dropbox. I added the Index to the back of the book and places the Index Page 461 in the Contents listing. This website section looks to be fairly quiet for awhile. I guess some time this fall I will be working with the publisher on the Type VII book. Once finished, I may start another book on the Type IX C. I currently have the drawings for the electrical schematics, and I have ordered the mechanical schematics from the Bundesarchiv via the Silke Archive Service in Germany... I believe we can make this website come alive again!

Regards,
Don_

tore · « **Reply #3027 on:** 21 Jun , 2016, 01:30 »

Don.
I read you last version of the Skizzenbuch and like your pages having roman figures describing diving and surfacing procedures, which is correctly understood. One detail though, when diving and surfacing using the tanks, you normally are manning the diving stations. This means a lot of people are moving around particulary from the crew quarters in the fwd. torpedo room to the aft control room, engineroom and aft torpedoroom. This has influence on the trim and you have to compensate this by using the fwd and aft trimtanks. So prior to giving the orders divingstation, you pump water from aft trimtank to fwd. trimtank, our experience was you needed approximately 400 liters, to compensate for the moving of people. Hence the trimtanks take a part in the diving and surfacing procedure as well. Likewise when the battlestation (which are almost the same as divingstation) orders are given. When the situation is cancelled you operate the trim tanks in the opposite way. In fact when being submerged you reacted on the first order: "pump 400 liters from aft to fwd." realizing it will soon be followed by diving station.
Tore

tore · « **Reply #3028 on:** 25 Jun , 2016, 09:18 »

Looking through old papers in my files I came over this cut I made from the french newspaper Le Figaro March 16. 1972. I remember it well, I was on a business trip in France and with my hotelbreakfast I got the le Figaro morningpaper, to my astonishment I saw my old submarine KNM Kaura ex-U995 hanging in the air on the frontpage. I cut it out and saved it. For those of you mastering french you can read the story bearing in mind in spite of 27 years had passed since the end of WW2 there was still some feeling of the event of placing the submarine on the concrete foundation at Laboe.
Tore

Don Prince · « **Reply #3029 on:** 26 Jun , 2016, 15:26 »

Hello Mr. Tore,

During a dive you have people moving to their dive stations and you seem to indicate that 400 liters of water is pumped from the aft to the fwd trim tank to compensate for the change in the U-Boat's trim. I believe I understand these trim adjustments. all personnel will remain at their assigned locations while submerged.

However, during an emergency dive addition crew personnel may move to the fwd torpedo room to give the U-Boat an additional bow down trim to accelerate the diving process.

1. Who gives the orders for that movement, or is it an understood procedure during an emergency dive?
2. Would they ever pump more water from the aft trim tank to the fwd trim tank for additional bow down trim?
3. Who would give such an order?
4. Who would act upon those orders?

Regards,
Don_

tore · « **Reply #3030 on:** 27 Jun , 2016, 00:44 »

Don.
It could depend on the cause for the emergency. F.i. if the officer on watch while the sub being submerged has to make an evasive dive (collision or ramming danger) at periscope depth, there is no time to change people,and you can`t use dynamic (hydroplanes) diving, steep angle, the officer of watch would order fill Q! An extra weight in excess of 4 tonnes gives a pretty good sinking effect and as Q is placed about midhips, there is no trimming moment and as people remains where they are, you don`t need to compensate using trimtanks.
If the officer on watch are free to to use dynamic diving he order the hydroplane angle and goes dynamically deeper and order pumping out water from the compensating tanks. Only in extreme using Q.
Thus emergency actions would not necessarily be carried out by diving station manning, but handled by the people of watch. But I can assure you, the CO and EO as well as the controlroom engineer would be in the controlroom in a split of a second to take over.
Such procedures would be laid down in the CO orderbook and usually every CO would require to be called in immediately to take over.
Using the trimtanks to get a bow down for going deeper would normally not be done, you can do a lot by hydroplanes and it is very smooth.
Tore

Don Prince · « **Reply #3031 on:** 27 Jun , 2016, 22:28 »

Hello Mr. Tore.

I was thinking about adding this info to the Prologue: diving sequence... What do you think???

"Using the trim tanks while diving or surfacing

During a normal dive procedure there are lots of people moving around particularly from the crew quarters to the fwd. torpedo room, the aft control room, the engine room, and the aft torpedo room. This movement has an influence on the U-Boat's trim and you have to compensate for this by using the fwd. and aft trim tanks. So prior to giving the order diving station, you pump water from the aft trim tank to the fwd. trim tank; our experience was you needed approximately 400 liters of water to compensate for the movement of people. Hence, the trim tanks take part in the diving and surfacing procedure. Likewise, when battle station order is given (which are almost the same as diving station) similar actions are taken. When the situation is cancelled you operate the trim tanks in the opposite way.

While on the surface, if the officer of watch orders an emergency dive, then we would have several things happening at once. There would be an order to pump 400 liters of water from the aft trim tank to the fwd. trim tank to balance the U-Boat, and then the crewmen are quickly manning their assigned diving station. In addition, there would be a mad rush of non-assigned crewmen to the fwd torpedo room. This would be the added weight of the human ballast to assist the U-Boat's bow in breaking the ocean's surface and getting the emergency/crash dive started expeditiously. The Q tanks would be of no additional assistance because they were already flooded while on the surface.

While submerged and the U-Boat is in a trim state; if the officer of watch has to make an evasive dive (collision or ramming danger) at periscope depth, there is no time to move people, and you can`t use dynamic (hydroplanes) diving, steep angle, the officer of watch would order fill Q! An extra weight in excess of 4 tons which gives a pretty good sinking effect and as Q is placed about mid-ships; there is no trimming moment and the crew remains where they are. If the officer of watch is free to use dynamic diving, then he orders the hydroplane angle and goes dynamically deeper. Only in extreme conditions using Q. Thus emergency actions would not necessarily be carried out by diving station manning, but handled by the officer of watch. However, I can assure you, the CO and EO as well as the control room engineer would be in the control room in a split second to take over. Such procedures would be laid-out in the CO order book and every CO would require that he be called in immediately to take over. Pumping additional water into the fwd. trim tank from the bow trim tank, even in an emergency, to get the bow down for going deeper would normally not be done because you want to maintain the U-Boat's trim; you can do a lot by hydroplanes and it is a very smooth process."

Regards,
Don_

tore · « **Reply #3032 on:** 28 Jun , 2016, 01:28 »

Don.
The various procedures on surface and submerged varies depending on the situation like weather, risk of be spotted, (airsuperiority) and are difficult to put down in a general rule. In the German navys Submarine commanders handbook for submarine ( U. Kdt. HDB) 1942, published by the San Francisco Maritime National Park Association, you`ll find the German Navy`s advices to their submarine commanders as of 1942.
I don`t think you should emphasize too much on adjusting the trim in emergency situations as time is the ruling factor. You are able to compensate the trim dynamically, and then using the trim tanks at a later stage.
Operating with the Q filled , I should think a risk of undercutting would exist. As you know the VIIC/41s and the some of the VIICs got the bow buoyancy tank and the Atlantic bow to reduce the undercutting risk, however with a low trim they encountered problems with the Junker compressor exhaust, all told, I would guess the use of low trim could vary between the various boats depending on their year and design. This is another discussion and may be it would be confusing to introduce in your Skizzenbuch.
Tore

Don Prince · « **Reply #3033 on:** 28 Jun , 2016, 14:49 »

Hello Mr. Tore,

How does this re-write look?

"Using the trim tanks while diving or surfacing

During a normal dive procedure there are lots of people moving around particularly from the crew quarters to the fwd. torpedo room, the aft control room, the engine room, and the aft torpedo room. This movement has an influence on the U-Boat's trim and you have to compensate for this by using the fwd. and aft trim tanks. So prior to giving the order diving station, you pump water from the aft trim tank to the fwd. trim tank; our experience was you needed approximately 400 liters of water to compensate for the movement of people. Hence, the trim tanks take part in the diving and surfacing procedure. Likewise, when battle station order is given (which are almost the same as diving station) similar actions are taken. When the situation is cancelled you operate the trim tanks in the opposite way.

While running on the surface, if the officer of watch orders an emergency dive, then we would have several things happening at once. The crewmen would immediate man their assigned dining stations, and there would be a mad rush of non-assigned crewmen to the fwd torpedo room. This would be the added weight of the human ballast to assist the U-Boat's bow in breaking the ocean's surface and getting the emergency/crash dive started expeditiously. The Q tanks would be of no additional assistance because they were already flooded while on the surface. Once they achieve the desired diving depth and dynamically level-off, then they can worry about balancing the U-boat when time permits. While silent running, compressed air instead of the trim pump motor is used to move water between the trim tanks if needed, thus eliminating the motor's noise.

While submerged and the U-Boat is in a trim state; if the officer of watch has to make an evasive dive (collision or ramming danger) at periscope depth, there is no time to move people, and you can`t use dynamic (hydroplanes) diving, steep angle, the officer of watch would order fill Q! An extra weight in excess of 4 tons which gives a pretty good sinking effect and as Q is placed about mid-ships; there is no trimming moment and the crew remains where they are. If the officer of watch is free to use dynamic diving, then he orders the hydroplane angle and goes dynamically deeper. Only in extreme conditions using Q - this emergency action would not necessarily be carried out by the officer of watch. I can assure you, the CO and EO as well as the control room engineer would be in the control room in a split second to take over. Such procedures would be laid-out in the CO order book and usually every CO would require that he be called in immediately to take over."

Regards,
Don_

tore · « **Reply #3034 on:** 29 Jun , 2016, 01:23 »

Don.
During normal diving procedure people take their divingstations which means people are moving from their quarters to the divingstations, generally this means from the fwd. torpedoroom to the controlroom and engineroom. Thus people are not moving to fwd. torpedoroom, I assume this is a misprint in your text.
While running on the surface the general German instructions for crash diving advises no special trimming to be done as a VIIC normally has a short diving time of 30 seconds, which you would need for disengaging and shutting down the diesels anyway, quicker than any preparation like moving people. Surfaced in enemy waters 1941 you had to be prepared for crash diving. Latter part of the 1944 you would be schnorchling.
During surface dieselcruising I should think using the surface dieselspeed inert and hydroplanes would contribute to the shortest crash dive.Normally you would probably hold the venting of MBT1 a bit to assist the bow down angle. However it is up to the CO`s judgement to issue the standing orders he may require in his orderbook. We usually kept the Q empty filling it only when needed.
I assume that your statement that the crew would immediate assume their assigned "dinnerstations" is a misprint.

I guess as I said before, the various way to handle the sub depends on circumstances, experience and the CO.`s judgment, as well as the development of the strategical situation which is changing. Thus I don`t think you should going into accurate details how to handle the sub under various situations in your skizzenbook.
In certain rare situations you may use people for trimming, I never felt the need for it.
Tore

Don Prince · « **Reply #3035 on:** 29 Jun , 2016, 17:00 »

Hello Mr. Tore,

Understood, I will leave it as original...

Thanks,
Don_

tore · « **Reply #3036 on:** 30 Jun , 2016, 07:18 »

Don.
Ok. As an additional info. I guess the submarine service of the German and the Royal Navy used Q differently, filling Q while cruising on the surface was seldom used in the RN, even if the RN submarines had forward folded hydroplanes above the waterlevel. Some CO`s might be tempted to cruise on the surface having the ballast tanks partly filled, a risky chance as the stability is reduced and the risk of undercutting is great. In the german navy partly filled ballast tanks was forbidden while cruising surfaced.
Tore

falo · « **Reply #3037 on:** 09 Jul , 2016, 00:43 »

Hi Tore,

I have a question about the "wasserdichte Back" (bow buoyancy tank). Do you have a picture or a drawing how the tank looks in three dimensions? (please see attached jpg).

I find on eBay a photo of a damaged type seven bow maybe it would be helpful to answer the question:
http://www.ebay.de/itm/U-BOOT-KRIEG-FOTO-U-302-NACH-DER-BUGKOLISION-KOMMANDANT-HERBERT-SICKEL-/231999050226?hash=item36043891f2:g:JV0AAOSwxvxW7dgu

Thanks in advance and best regards
falo

tore · « **Reply #3038 on:** 09 Jul , 2016, 02:27 »

Falo
I am sorry I don`t have a 3D drawing of the bow boyancy tank. Looking at the sketch you posted I guess you have reduced the wasserdichte- back a bit too much. In general the tank is placed between frame 102 and 113 and goes out to the bowcasing.This means that the HP flask is inside the tank and I guess the anchor chain goes via a chainpipe to the anchor bay. As you probably know the tank has freeflood slits in the bottom and vent on the top. Right fwd of the tank is a forepeak, kind of small collision peak. See my sketches below.
Tore

falo · « **Reply #3039 on:** 09 Jul , 2016, 04:27 »

Hi Tore,

thank you very much for your fast and detailed reply.

Sometimes I wish I could drive to Laboe with a big can opener in my instrument case to open the outer hull of U-995 and photographing every small part of the inner structure. After that project I will post a very detailed photo report here, promised

Thanks again and egards
falo

tore · « **Reply #3040 on:** 09 Jul , 2016, 05:07 »

Hi Falo.
Crawling inside the casing of U995 would not give you much info. I believe it i is almost an empty space as painting and maintaining this space is very difficult. When I was the EO of U995 I crawled all over and as I used to be a skinny guy, I got access to everything, today age and kilos would effectively prevent this even with a can opener!

Tore

Don Prince · « **Reply #3041 on:** 27 Jul , 2016, 14:33 »

Hello Mr. Tore,

Well, I'm starting a new project "Skizzenbuch: U-Boat Type IX C Project"... I have attached Image 045.jpg which looks to be very similar in design and functionality to the Type VII C compensating water system with the water source coming from the Diesel Engine cooling water. What do you think?

Regards,
Don_

tore · « **Reply #3042 on:** 28 Jul , 2016, 00:53 »

Don.
IXC type is of course a bit outside this thread and I have never served on a IXC, but still it is interesting to make a comparison between VIIC and XIC. When comparing the watercompensating system, I agree there are a lot of similarities however as can be seen on my sketch below the external compensating water of the IXC seems to have a common supply pipe from the silencer/sparkarrestors to the headertank and the external fueltanks, which simplify the system. The internal system is basically the same.
Tore

Don Prince · « **Reply #3043 on:** 28 Jul , 2016, 16:02 »

Hello Mr. Tore,

My Type IX project will take a year, or more, to completion... Can we use the current mail box, or should there be another Tore's mail box created for the Type IX U-Boat? There doesn't look to be anything really different between the two types of U-Boats. I'm sure with my new found knowledge and input from you, Maciek, and others, we could have an interesting topic and great informative discussions. What is your advice?

Regards,
Don_

tore · « **Reply #3044 on:** 29 Jul , 2016, 00:25 »

Don.
I have of course no objection to include IXC in this thread. As to my contribution, I am afraid it would primarily be theoretical, based my VIIC and general submarine knowledge as I don`t know the IXCs in details. However as I said it might be of interest to have a discussion about the difference between the two types VIIC and IXC. As I have practical no manuals, drawings or books on the subject it might be convenient if you put forward the topics you would like to discuss enclosing the relevant attachments. You could perhaps start with the basics like development history, physical dimensions, GA plans, rudder and hydroplanes, periscopes, torpedo arrangement, main engines and E-motors etc. if you have details of same. I am sure apart from our old friends, there are people out there having substantial knowledge of the IXC, and although very similar, a discussion of the difference between the two types could have some interest I guess.
Tore

karel · « **Reply #3045 on:** 31 Aug , 2016, 03:21 »

Hi Tore, Don, Maciek. I am new member to this forum and hope if you don't mind for me asking a lot of silly question about the operations of VII.

A little introduction about me. My name is Karel and i am in the same situation like Mark, i am also developing a submarine game. Only i am not trying to recreate physics and 1:1 since my experience will be a bit different. It is a game that is played trough virtual reality headset (Oculus Rift and HTC Vive) and will have a multiplayer element. What i am trying to achieve is to recreate the feeling of being inside the submarine. For the past 2.5 years me and my team have been recreating the Interior of VII u-boat. Since the game is built ground up for virtual reality, we had to turn a lot of attention to all these small details. Of course we cannot recreate 100% of the interior details with the top visual quality because no computer would be able to play them. (VR game needs to run 90 frames per second)

As for the gameplay. Since the game can be played alone, or with a friend we wont put player trough heavy process of an actual submarine control. Its too complicated and would need more people. Since players are in virtual reality and have hand controllers they have to physically turn all those Valves and vents. So instead we are going for the easier and fun route where 1 player can manage the control of the U-boat if he needs to. But.. this opposes another problem, since we want the u-boat interior to feel authentic we still want to model at least 60-80% of all the control elements and. Easy fix for them would just to have these as props, an eye candy that cannot be interacted with. Again problem is that in virtual reality if you already have some interaction build for certain valves, then user automatically will assume that everything is intractable. So we decided that every valve has to have some sort of meaning, so when player turns a valve that regulates oxygen levels in different compartments then he/she is able to do so. We can easily add some sound feedback, like a hissing sound that travels trough the oxygen pipes. This will give no affect to gameplay itself but still adds agency to the player making him/her feel that every action has a meaning (even if this meaning has no gameplay value)

Other aspect would be purely educational. They could walk around the boat and learn the meaning of every operation that was done inside the u-boat. What i would like to avoid is making a gross errors like confusing flood valves with oil valves and etc.

https://www.youtube.com/watch?v=hYMoLe5ZSaQ - here is the video of the game. It is still a very much a work in progress. Also do not mind, no operation there is historically correct. I needed a prototype asap and many of these things were made up for speed purposes. Now that our u-boat is in the finishing stages it is time to start researching about the controls.

So this is the reason why i joined this forum. I found you brilliant people and was hoping to ask many many questions about what some or other instrument inside the u-boat does. Then i could use this information to create a "semi-realistic" virtual tour of the u-boat that has all the objects intractable.
I am aware about the book that Don is making and it would save me months of research work but sadly it is not available yet.
So i am hoping that you gentlemen do not mind if i stick around and ask many questions.

----Questions

My first question about all those lost image materials that come before page 200. Are all these lost, i cannot see them? When i download the attachment they seem to be broken. Seems that the site was offline and after coming back all this information is lost?

My second question is about attacking other boats. As i understand that neutral buoyancy was almost impossible to achieve. Does that mean all attacks trough the periscope must be done when boat is moving because then hydroplane operators can fine tune the depth?

Third question is about the ballast. When i am filling all MBT1,2* MBT2, MTB3, 2* MTB4 and MBT5 100% and not touching the negative buoyancy tank. How deep does the boat go until it starts to approach its neutral buoyancy?

Thank you. And i apologize for the wall of text

tore · « **Reply #3046 on:** 31 Aug , 2016, 09:36 »

Karel, welcome to the forum and my mailbox, I admire you intentions and shall try to help where I can. I am afraid the lost images up to page 200 is lost due to a crash of the system but the knowledge is here and I have quite a few of the images in my file so just shoot you questions and we`ll see what I can do.
Second question. Neutral buoyancy is not necessary for attack in fact sometimes not even desireable. If your submarine is weightless it requires a small force to move it and your are unstable. As in open sea you generally have swell and waves moving the submarine you want to counteract these movements by dynamically controlling ( by hydroplanes and speed) the submarine. Attacking at periscope depth is the most common attack and you are relying on your hydroplane operators and the trim. The trim (regulating tanks are filled according to experience, calculation and weather) and the hydroplane operators using their hydroplanes watching the Papenberger, a depth gauge having a scale where you can read the position of the attack periscope in relation to the sea surface. See attached image. I guess the only time you are using a accurate neutral buoyancy is when hiding either for escape or observation. You search for an interface between to different densities of water ( sonar mirror), put you submarine under the layer, adjusted to neutral buoyancy trim, shut down all machinery (dead silent) and adjust minor differences in displacement by lowering and raising the periscopes. This can be done silent if you top up your hydraulic accumulators and use the stored hydraulic energy to lower and raise the periscopes.
Tore

tore · « **Reply #3047 on:** 31 Aug , 2016, 15:06 »

Karel, I realize I forgot your third question. When the main ballasttanks are not used for fuel, they are only used for diving the submarine and do not participate in the trimming. Prior to the diving, the regulating tanks are adjusted to the calculated desired trim submerged at the requested depth. When diving requesting a quick dive you use the Qs ( Untertriebzelles) to overcome the "surfaceresistance" for the first part of the dive. The Qs are blown as soon as you are submerged, generally at some 8-10 meters and the submarine is at the right trim at the required depth if the regulating tanks are adjusted correctly, if needed the regulatingtanks can be corrected when submerged by the main ballastpump. If you want to take the submarine further down, the pressurehull is compressed and the displacement is reduced and you loose buoyancy, this has to be compensated by pumping out water from the regulatingtanks 1 and 2 port and stb. corresponding to the loss of buoyancy. For a VIIC this would be about 100 liters seawater per 10 meters. As you probably know, a pair of the regulatingtanks 1 can be used for fuel, which reduces the flexibility of the regulating tanks when in fuel configuration. The same happens when MBT 2 and 4 port and starboard are in fuelconfiguration, which means the ballasttanks are partly filled with diesel fuel having a specific weight less than seawater. You have to compensate this by using regulatingtanks 2 port and starboard which cannot be used for fuel. All told, the regulating tanks plays an important part in the trimming of the submarine and not the MBTks as long as they are not in fuelconfiguration.
Tore

karel · « **Reply #3048 on:** 02 Sep , 2016, 06:41 »

Thank you Tore. Based upon your feedback i think that i have made pretty good diving system for my game. Its not 100% realistic, but still has some complexity and is not "push one button to dive" system.

About the tanks itself. I read somewhere (possibly in this thread) that all the diving tanks had to be empty or full. There was no in-between solutions like only flooding 50% of a certain tank. Why was it that way? Did the boat become unstable?

Another theoretical question about neutral buoyancy. It may be confusing but i try to explain. I apologize if i do it badly

Lets say commander achieves near neutral buoyancy with the slight force that moves the boat up. Is the upward momentum a continuous force and the boat will eventually reach near the surface? Theoretically i think that the upwards movement should continue to happen until the boat reaches shallower depth where pressure is smaller, and the weight from ballast tanks will become an issue again and makes the boat sink again.
Is this right?

Thank you. Btw. I love your name. Tore in my native language means the word "great"

tore · « **Reply #3049 on:** 02 Sep , 2016, 10:02 »

Karel.
The reason for having the tanks either empty or full is to avoid what we call the surface effect. When you have only partly filled liquid in a container which is moving you get a rapid shifting of the center of gravity of that tank as you create a local wave in the container and a submarine is susceptible to these movements. To avoid that, you keep the tanks for liquid either full or empty. As a consequence of this effect all the fueltanks are always full eg. seawater compensated, meaning you let the seawater fill the empty space left when you are consuming the fuel. The fuel " float" on the top of the compensating water as seawater has a higher specific gravity. In those cases where you cannot avoid partly filled tanks, like regulating tanks, you "chop up" these movements by fitting ripple/splash bulkheads in the tank allowing the liquid to move but only in smaller quantities. Further you try to place these tanks as close to the submarines gravity/buoyancy center as possible reducing the impact moments. There is no in between solutions, but as you gradually fill the fuel tanks and the ballasttanks in fuel configuration with seawater, the weights and moments changes thus you have to calculate and adjust that by the regulating tanks and some times even trimtanks.
If the submarine is having a slight positive buoyancy at a certain depth, it don`t only ascend, but shall have a slight acceleration upwards as the hull is expanding increasing the displacement. If any residue air is left in the ballasttanks this air shall expand as well and force the ballast water out of the Kingstons increasing this acceleration. Eventually the submarine shall break the surface sometimes higher than equilibrium due to inertia forces before she rest on a surface draft corresponding to the weight /displacement balance. This could be an uncontrolled stability position as the MC (Metracentric centre) is changed. As you know this procedure take place when surfacing, you raise the submarine dynamically to periscope depth, then by HP air blow your MBTs only partly to save HP air resulting in being only semi surfaced and unstable before you start blowing, by the diesel exhaust, the main ballast tanks at a certain sequence until you are fully surfaced.
As to my name your native tongue is not far off. The name is from the Viking god Tor, who is the God of thunder and lightning. I guess he was pretty big.

Tore

Don Prince · « **Reply #3050 on:** 05 Sep , 2016, 12:45 »

Hello Mr. Tore and All,

My wife, Maureen sent me this link from her cell phone... The final resting place of U-576 a type VIIC that was lost in 1942 off the North Carolina coast.

http://www.dailymail.co.uk/news/article-3774630/The-ghosts-U576-German-U-Boat-30-miles-coast-North-Carolina-72-years-sank-Nazi-campaign-terror-44-soldiers-entombed-inside.html

Regards,
Don_

tore · « **Reply #3051 on:** 05 Sep , 2016, 15:00 »

Don. Reading the newsarticle I noticed they state the wreck was located August 24. 2016. I guess it has previously been published she was located 22. October 2014. One of her ballasttanks was damaged, hampering her diving and surfacing capabilities prior to her last attack. I guess the damaged tank could probably have been one of the saddletanks.
Tore

karel · « **Reply #3052 on:** 07 Sep , 2016, 06:46 »

Tore.

Thank you for explanation. I added this behaviour to my diving system. I have read the word "Kingston" here a lot but since pictures are gone it is hard to put it into context. Is this some kind of valve? Do you have a picture of it?

Also trying to figure out submarine speed. Wikipedia says that under water the max speed was 7.6 knots. Was that speed always constant or did it decrease when submarine went deeper? Could it actually run at 7.6 knots when at 155-200 meters?

tore · « **Reply #3053 on:** 07 Sep , 2016, 07:41 »

Karel. Kingstons are named after a British engineer living in the latter part of 1700 who invented the valvetype. It is merely a bottom valve allowing sea water to enter into any ships hull. For a submarine this means specifically the bottom seavalves of the ballasttanks allowing seawater to enter the tanks when diving. Kingston are usually always open when the submarine is at sea and shut when alongside in the harbour for safety. They are cumbersome to operate by removeable cranks which are placed on the square of the valvestems, usually in the controlroom. Theoretically you could sink a submarine if laying alongside by opening the ballasttank vents if the kingstons were open. Sometimes you would shut the Kingstons when depthcharged preventing the shock waves to enter the ballastanks. Below is my model of KNM Kaura ex U-995 showing the Kingstons in this case square flapvalves in the bottom of the saddletanks and MBT 3.

tore · « **Reply #3054 on:** 07 Sep , 2016, 08:13 »

Karel. Speed of the VIICs submerged . Speed submerged (or may be the water resistance) is not changing noticeably within the submarines operation depth range, and depends thus primarily on the power available at the propellershafts. The VIICs and many of the WW2 submarines had a low submerged speed as the e motors did not have the powers to exceed the speed mentioned by you. The German submarine tactic "Wolfpack" would be to gather several Uboats where they assume a convoy would pass, carry out the attack requiring slow speed. After the convoy passed, reload the torpedoes, when ready, proceed on surface at high speed 17-18 knots overhauling the slow convoy (7-12 knots) by powerful diesels, dive ahead of the assumed course of the convoy and repeat the attack. Modern submarines of today are differently designed and adopted to different tactics which requires higher speed submerged.
The E-motors were not a constant power motors and the speed and direction of rotation varied, in fact as the diesels of the VIICs after 1942 had the reversing removed, the E-motors were the only motors used for maneuvering able to revers and having variable speeds. Finally the e-motors were used as generators as well, driven by the diesels charging batteries solely or combined when diesel cruising on the surface.
Tore

SG · « **Reply #3055 on:** 08 Sep , 2016, 02:15 »

Great piece of intel, beautiful uw footage shots and original b/w pics, Don. Thank your wife on my behalf!

karel · « **Reply #3056 on:** 08 Sep , 2016, 08:58 »

Really good information

So i think that my diving system is pretty good at the moment. Played in virtual reality today and the new diving system added a new dimension to the gameplay. Instead of going to x depth and calling it a day, i know have to keep the boat in balance and in trim. If i constantly do not watch and adjust my bearings i risk to sink the boat or surface. Lets just say that evading a depth charge became much more complicated. Hopefully i can get multiplayer working correctly so people could divide up the tasks in the sub. Running alone in sub, adjusting instruments, keeping track of the enemy and evading, even though it is all super simplified it can be a daunting task to handle alone.

Tore. Are you able to tell me how fast did those tanks filled up with water? I guess different tanks had different speeds since their size were not the same. I am mostly interested in tank3, tanks 4 and 2, tank1, tank5, and negative tank. These tanks are represented in my game.
I also have a trim tanks represented in the game that shifts gravity from one end to another if needed. As for gameplay reasons i had to add another "special unrealistic cheat compensating tank" that just holds the boat at neutral buoyancy at periscope depth. Otherwise it would be impossible to play this game as a single player experience since you would need to constantly jump between the hydroplane controls and periscope.

tore · « **Reply #3057 on:** 08 Sep , 2016, 11:47 »

Karel. You cannot fill the ballast tanks independently as you shall upset the trim both atwartship and alongship. What matters in real life is how fast you can dive in emergency. The ballasttanks 2, 4 port and starboard as well as MBT 3 have all Kingstons dimensioned for the capacity of the tank and a quick filling, MBT 1 and 5 have no Kingstons but free flood gates with ample dimensions, adopted to the quickest diving time. All the MBTks particularly MBT 2 and 4, and MBT 3 have quick vents by pull down handles, MBT 1 and 5 by hand wheels, all situated in the controlroom.
An optimal quick dive can be obtained by following a special procedure. When approaching hostile waters you fill the Qs and increasing the draft, but primarily to assist to overcome the "surface resistance", the regulating tanks adjusted to the COs request for a buoyancy at a particular depth. At the order for an emergency dive you open the vents for MBT5, MBT3,MBT2 and 4 port and stb, for MBTs 2 you open the residue air vent waiting to vent MBT1 to assist the bow down angle. When the boat start to dive bow down you normally open the vent for MBT1, the boat is controlled dynamically ( by speed and hydroplanes)at angle of 8 degrees to prevent the stern to be too high above the surface, a rough control by the periscope would be the towers wind deflector is at the sea surface simultaneously with the aft end of the boat. At 8-10 meters you blow the Qs and the boat has a required buoyancy at f.inst. periscope depth. By following this optimal procedure you can obtain a diving time of 30 seconds which is pretty good and considerably quicker than f.inst. a IXC.
Tore

karel · « **Reply #3058 on:** 13 Sep , 2016, 05:06 »

Really appreciate your input Tore.

Few questions about regulating tanks. When you need to correct your regulation when submerged, you can do it so at the main ballast pump. Can you give me a brief explanation how this was done? I am looking at the screenshot and see bunch of red valves lying on the floor. Did these Valves all work in a combination? Lets say i need to pump more water to aft and thus only rotating certain Valves.
Also doing trim when you are surfaced. Did you use same valves or was the trimming on surface done differently?

Thanks,
Karel

tore · « **Reply #3059 on:** 13 Sep , 2016, 08:39 »

Karel.
The regulating tanks are used all the time and the operation of same is in the controlrom. The regulating tanks can be operated in many ways by:
1. The main ballast/bilge pump being a two stage sentrifugal pump. The 2. stage used to discharge to sea at greater depths.
2. The trim/aux. bilge pump being a pistonpump.
3. By hp air.
Further regulating tanks 1 can be used as fueltanks as well.
This require a somewhat complicated pipe and valve systems to handle all the alternative and fairly confusing to a layman so I guess I should start with alternative 1. being the most common.
On my image below you see the pipesystem for the main ballast pump, capacity 1300/1465 liters / min. against 15 meters. and the 4 regulating tanks in seawater configuration, green regulating tanks 2 and yellow regulating tanks 1. Corresponding pipelines coloured as the tanks. On the photos you see the valve chests with valves. If you want to pump out regulating tank 2 port and starboard with say 100-200 liters, you probably would like to use the smaller aux. bilge/ trimpump having a capacity of 300/360 liters pr min. You open the valves for the yellow pipeline, and discharge to sea, via the boardvalve b , in this case you may read the amount discharged on the watergauges for reg.tanks 2 port and stb marked off per 100 liters, indicated on the image below. In case you are afraid of leaving an oilslick on the surface you don`t discharge to sea, but into MBT 3 s boardvalve (dotted pipeline) on the drawing.
If you want to fill more seawater into the tanks, you don`t use the pumps but merely open the sea valve "a" and follow the volume on the water meter in the pipeline till you have the correct amount into the tanks. The regulating tanks are vented into the controlroom as can be seen on the system drawing.
The above system is used both on the surface as well as submerged.The valve are indeed used in combination, but not mechanically interconnected.The forward aft- trim is a separate system and although you use the same pumps, you have forward and aft trim tanks, the pipelinesystem is different but interconnected. Both systems can be operated by compressed air as well.
It might require some studying of the of the different systems to have a full understanding. I fully understand the difficulty to have a 100% correct understanding, but these systems are very important in a correct operation of a submarine so just ask your questions.
Tore

maillemaker · « **Reply #3060 on:** 13 Sep , 2016, 11:31 »

Hello Tore!

I joined this forum so I could say "hi" to you and to say thank you for participating in this forum and thread to tell us what it was like operating a German u-boat!

Steve

tore · « **Reply #3061 on:** 13 Sep , 2016, 11:42 »

Steve thanks, if you have any questions, shoot I am going on 88 so don`t hesitate

!
Tore

maillemaker · « **Reply #3062 on:** 13 Sep , 2016, 13:12 »

Hi Tore!

Thanks! To be honest, one of the reasons I jumped in here so quickly when I discovered this thread was to be able to say hi and thanks before you were gone! I am 46 years old and over the years there have been so many people of historical note that I wished I had had a chance to speak to that were gone before I realized I had the chance to do so.

For example, I have been trying to get an address for Rienhard Hardegan, who is like 103 years old and supposedly still resides in Bremen, to send him photographs of the Silent Hunter 5 u-boat simulation program, to show him what people are up to these days in remembrance of their deeds of long ago.

I have long been a fan of the Silent Hunter series of PC uboat simulations, having played them for a decade or more now. Plus other uboat sims before that. I have just now undertaken building the Revel VIIC/41 Atlantic Version and so have been inspired to hunt down internet sources for ideas.

I have opened up the long flood opening above the saddle tanks and am adding ribs as many modelers do. I want to replace the "box" around the snorkel recess area with appropriate deck support structure. Are there any pictures that show this area of the uboat without the decking in place?

I am slowly working through this long thread - I am on page 8. Sadly many of the referenced links and even attached pictures no longer work.

Thanks and nice to meet you,
Steve

maillemaker · « **Reply #3063 on:** 13 Sep , 2016, 14:50 »

Another question:

On many models, and on the U-995 museum ship, at the point of the saddle tanks is shown a "drip rail" with holes just above it for draining.

It would seem to me that this would be underwater at all times while the boat was in service. Is the drip rail something added after permanent dry-docking?

Steve

tore · « **Reply #3064 on:** 13 Sep , 2016, 15:07 »

Steve, do away with the gutters installed on the museums U 995 they were of course not on the original. Reverting tomorrow with the schnorchel details in the casing, do not copy the museums U 995.
Tore

tore · « **Reply #3065 on:** 13 Sep , 2016, 23:56 »

Steve.
Recess for schnorchel mast. I dont think you should make a box for the schnorchel recess. I have seen a couple in the IXC casing. just a box around the schnorchel head, made of plain thin steel plates having drilled holes, I can`t remember we had such a box. When the schnorchel mast was lowered, it rested on cradles fitted on the pressure hull, right above the COs cabin you had a lockingclamp entering an eye on the mast. The clamp had a spindle going into the top of COs cabin ending in a handle to lock the mast in resting position. Otherwise the space around the mast was pretty empty just surrounded by angled thin steel girders and steel supports for the casing and wooden deck.
The raising cylinder and crank was quite different from to days museum U- 995 mock up as can be seen on my image below. The whole thing was half way above the casing deck. As a bonus I post an mage of me inspecting the original schnorchelmast of KNM Kaura ex. U 995 some time in 1953.
Tore.

karel · « **Reply #3066 on:** 14 Sep , 2016, 02:45 »

Thanks. I think got enough out of it (after reading carefully 5 times) in order to figure out how to fit a simplified version to the game. So i have been trying to research about all the valves that are located in command room. We have most of them modelled out in game and i would like to know what did they do so i could give them a right functionality.

This is from my research from all various sources. Sometimes they conflict badly and they are probably wrong.

On screen1
1) Flood ballast tank2 stb
2) Flood ballast tank2 port
3 and 4) No idea. Something to do with oxygen?

On screen2
1,2,3,4 Somekind of emergency flood crank to quickly fill up tanks. I think one of them were MBT3 or MBT4&2
5,6 - Valves to close/open air intake pipe that goes into engine room? The one that almost caused a serious accident on your patrol when someone forgot to close them and added 5 tons of water when the boat was diving.

Again, many many thanks. For these past few weeks i gathered more information from you than any other source where i did research for months.

maillemaker · « **Reply #3067 on:** 14 Sep , 2016, 07:32 »

Quote

Recess for schnorchel mast. I dont think you should make a box for the schnorchel recess. I have seen a couple in the IXC casing. just a box around the schnorchel head, made of plain thin steel plates having drilled holes, I can`t remember we had such a box. When the schnorchel mast was lowered, it rested on cradles fitted on the pressure hull, right above the COs cabin you had a lockingclamp entering an eye on the mast. The clamp had a spindle going into the top of COs cabin ending in a handle to lock the mast in resting position. Otherwise the space around the mast was pretty empty just surrounded by angled thin steel girders and steel supports for the casing and wooden deck.

So basically the floor of the "box" is just the top of the pressure hull, right?

In this version of your photograph, which I found in Foxbat's build thread, you can see a little bit more of the snorkle.

It appears that there might be some kind of platform that the snorkle is lying on elevated just slightly above the pressure hull?

tore · « **Reply #3068 on:** 14 Sep , 2016, 12:21 »

Karel.
It is not easy to go into valve and vent details in the control room. I am afraid you got it a bit wrong. May be we should go back to the basics. What makes a submarine dive are the main ballast tanks, they are therefore controlled from the control room. For a VIIC you have 8 main ballasttanks MBT1, 2 port and stb. 4 port and stb, MBT 3 which is having a central bulkhead making it port and stb although it is basically the same tank and MBT 5. At the same time we have two buoyancy tanks situated in the bow and the stern. They are not considered as ballast tanks as they are originally designed to give extra buoyancy on the surface to reduce pitching, nevertheless they have to be vented when diving, so you have to open the buoyancy tank vents as well. Contrary to many other submarines the VIICs was equipped with mechanical operated vents , and when you would have the controls in the control room this means that the forward and aft vents had to be operated by long rod transmissions going through bulkheads and compartments. A cumbersome arrangement which require a lot of maintenance and greasing. Below I have made a drawing using one of Simon Morris excellent images as a base in order to explain what I am trying to say. Hopefully the image and text shall give you the answer. Unfortunately I had to split up the drawing as the file is too large. Just ask if something is unclear.
Tore

tore · « **Reply #3069 on:** 15 Sep , 2016, 00:48 »

Karel.
I realize the residue air might be a bit unclear. When you have a steep angle bow down diving , it is difficult to vent the aft MBT 2 port and stb as air would be trapped in the aft part of the tanks, colored yellow on my sketch below, hence an extra venting pipe ( yellow) and a common port and stb vent for the aft part of the tanks, operated by a long rod from the control room.
I forgot your assumption on the smaller bulkhead wheels, this has nothing to do with the diving, they are the shut off bulkheadvalves for stb and port ventilation ducts.
Tore

tore · « **Reply #3070 on:** 15 Sep , 2016, 01:38 »

Steve.
Schnorchel mast recess in casing. Below is an image showing the original U 995 execution VII/C 41 of the schnorchel with locking pin in lowered postion as well as raised.
Tore

tore · « **Reply #3071 on:** 15 Sep , 2016, 02:51 »

Karel.
Finally, your screen2. You are right in your assumption as to valve 6, this is the diesel air supply main intake valve going via a pressure proof duct outside the pressurehull to the board valve in the engine room ending near the bilge on each side of the diesels. The smaller wheel is for the ventilation system going in the same way to the ventilation intake valve and ventilation fan in the engineroom. The reason for having two air intakes is the diesel air system was susceptible to seawater flooding in bad weather hence the outlet ending in the engine room bilges, a complete separated system with ample draining was used for the ventilation system to prevent seawater penetration and damaging the electric fan motors.
Tore

karel · « **Reply #3072 on:** 15 Sep , 2016, 05:39 »

Tore.
Just to make sure i understand right. The "long rod transmission" this means these rods (1,2,3,4) that are on the upper hull on screen2?

I hope that i am getting this right. The rods number 1 and 3 are for opening vents for MBT 2&4 port and stb. The rods 2 and 4 are opening MBT3 port and stb.

tore · « **Reply #3073 on:** 15 Sep , 2016, 06:36 »

Karel.
I am afraid, not these are pull down handles for MBT 3 stb and port, the long rods for mechanical opening of the forward and aft vents are indicated on the image below.
Tore

karel · « **Reply #3074 on:** 15 Sep , 2016, 07:28 »

Thank you for explaining the rods. Now i understand the context better and am able to fully understand your description.

Do you have pictures of handwheels for aft buoyancy tank?
I am also unable to locate the handwheels for negative buoyancy tank port&stb. If i am not mistaken then these tanks itself should locate between regulating tank and MBT4. I guess their handwheels should also be in command room somewhere.

tore · « **Reply #3075 on:** 15 Sep , 2016, 08:21 »

Karel. You could not pick a more complicated item. When the Junker free piston compressor was installed in the aft torpedoroom of the VIICs they experience problem with the exhaust back pressure of the Junker compressor. In order to solve this, they made an interlock with the aft buoyancy tank vent so you could not open the exhaustvalve unless the buoyancy tank vent was shut, preventing the stern to be too low in the water, hence the complicated arrangement as can be seen on the image below. However your question as to the location of the vent handle you`l see same on my images, as you see, this vent cannot be operated from the control room.
Tore

maillemaker · « **Reply #3076 on:** 15 Sep , 2016, 08:47 »

Hi Tore!

Thanks for the replies on the snorkel.

So if I am interpreting the illustration correctly, the snorkle rests directly on the pressure hull when in the lowered position.

So, on my Revell 1:72 model, I am building the pressure hull and saddle tanks under the deck in that region, and I will omit the "box" structure provided with the kit, except for the hinge section. I will build in appropriate deck supports around the opening.

Steve

tore · « **Reply #3077 on:** 15 Sep , 2016, 08:55 »

Steve, I guess you`ll be well off with such a solution.
Tore

maillemaker · « **Reply #3078 on:** 15 Sep , 2016, 08:57 »

So what would you say is a ballpark number of valves that had to be manually opened/closed every time you dove or surfaced the boat?

It seems very complicated!

Steve

tore · « **Reply #3079 on:** 15 Sep , 2016, 09:04 »

Steve. All the valve were manually operated. Kingstons, vents, exhaustvalves etc. I guesstimate some 30- 40 vents/valves altogether including valves for HP blowing and exhaust blowing.
Tore

maillemaker · « **Reply #3080 on:** 15 Sep , 2016, 09:07 »

Quote

Steve. All the valve were manually operated. Kingstons, vents, exhaustvalves etc. I guesstimate some 30- 40 vents/valves altogether including valves for HP blowing and exhaust blowing.

Cool. How many people were required generally to operate all the valves? Seems like a lot of coordination is required!

Steve

tore · « **Reply #3081 on:** 15 Sep , 2016, 10:52 »

Steve.
Diving would require some 7-10 people operating the vents manually, further 3-4 men in the engine room shutting the hull valves. Surfacing, one man, the control room engineer at the blowing panel as many of the HP air valves were adjusted on beforehand allowing only the main blowing valve to be operated. No men at the vents as the vents are shut when submerged, however in war time the vent operators would be stand by at diving stations. Each man knew exactly what he should do, the drill was done during the work up periode and you did not give any other order than dive, dive, dive, the coordination was done on beforehand.
Tore

maillemaker · « **Reply #3082 on:** 15 Sep , 2016, 11:58 »

Quote

Diving would require some 7-10 people operating the vents manually, further 3-4 men in the engine room shutting the hull valves. Surfacing, one man, the control room engineer at the blowing panel as many of the HP air valves were adjusted on beforehand allowing only the main blowing valve to be operated. No men at the vents as the vents are shut when submerged, however in war time the vent operators would be stand by at diving stations. Each man knew exactly what he should do, the drill was done during the work up periode and you did not gave any other order than dive, dive, dive, the coordination was done on beforehand.

Fascinating stuff! Did the German u-boats have a "Christmas tree" like the US subs to indicate the status of all the valves?

Steve

tore · « **Reply #3083 on:** 15 Sep , 2016, 14:39 »

Steve.
Christmas trees were common on the VIICs, below is an image of the blowing panel, as you probably know the VIICs used HP air for blowing the ballast tanks, the blowing christmas tree consisted of a common blowing valve for all the ballasttanks, each tank could be individually adjusted as nessesary by a separate valve after the main blowing valve, which of course resulted in a lot of valves. In order to save HP air you only blew the main ballast tank partly by hp air and continued blowing the residue by exhaust from the main diesels. The system required a constant adjusting of the exhaustblowing as the resistance varied because the ballasttanks were situated at different depth and thus the counterpressure varied, if not adjusted the exhaust would only work on the tank having the lowest counterpressure. Thus you must be able to distribute the exhaust to the right tanks. This panel or christmastree if you like, is situated outside the pressurehull having the adjusting valve wheels on top of the blowing panel as can be seen on the image.You started to exhaust blow the the MBT 2 & 4 being closest to the surface (least resistance ), then shut the valves to MBT2&4, continued with 1 and 5 now having the lowest resistance and as the submarine ascended shut the MBT 1 and 5 and finishing up with the MBT 3 the (deepest tank highest resistance ) now having an acceptable resistance, until you was completely surfaced. This required a constant surveillance by the operator and a frequent adjustment of the valves in the exhaustblowing panel.
Tore

VIC20 · « **Reply #3084 on:** 15 Sep , 2016, 14:43 »

Quote

below is an image of the blowing pane

Your forgot to add the image.

tore · « **Reply #3085 on:** 15 Sep , 2016, 14:49 »

You was too quick, I had the image loaded but it was too large and I had to make it smaller hope everything is OK now.
tore

maillemaker · « **Reply #3086 on:** 15 Sep , 2016, 14:59 »

Hi Tore,

That is not the kind of Christmas Tree I was talking about - on US subs they had a series of red and green lights (like are on a Christmas tree, thus the name) that indicate the open/closed status of hull valves.

Here is one from the USS Drum (Gato class):

Steve

maillemaker · « **Reply #3087 on:** 15 Sep , 2016, 15:01 »

Tore:

In your picture of the VIIC Christmas Tree, why do some valves have rope windings on the handle? Do they get hot/cold from the air passing through them?

Steve

tore · « **Reply #3088 on:** 15 Sep , 2016, 15:31 »

Steve. I thought you used the same valvecluster nomination as the offshore oilexplore people which is a stack of valves on top of an underwater oilwell. No the VIICs did not have your type of xmastree the closest I can get is the light controlpanel for the essential hullvalves as on the image below.
Tore

tore · « **Reply #3089 on:** 15 Sep , 2016, 23:52 »

Steve. The valves on the blowing panel were of a special construction having a valve cone designed as a reduction valve. The green handle wheels were the HP group valves direct connected to the HP flasks max. 205 bar. or slightly in excess of 2900 lbs/sq.inch. The main blowing valves reducing the pressure from max.205 to max. 25 bar and the distribution valves reducing the pressure to appropriate adjusted pressure for the relevant ballast tanks. The rope windings on the handles are insulation, this can be seen in particular on the exhaust blowing panel. The dieselexhaust valves gets hot, the HP air reduction valves get cold.
Tore

karel · « **Reply #3090 on:** 16 Sep , 2016, 02:10 »

The name christmas tree was also confusing for me when i started my research. In U-boats the christmas tree was referred as the blowing panel. In US submarines the christmas tree was the indicator panel.

Tore
The last picture that you posted. I see one big red handwheel on upper hull. Between the green and grey valves. Do you know the purpose of that handwheel?
Also about the red blowing valves. Currently my game the main blowing valve working but i would also like to add the functionality for these smaller adjusting valves for individual ballast tanks. Can you help me identify them?

tore · « **Reply #3091 on:** 16 Sep , 2016, 02:51 »

Karel.
The large red wheel is the common blowing valve of the stb. and port Q tanks ( untertriebzelle). The wheel with a black rim is the stb Kingston ( floodvalve) for stb. Q. A similar Kingston is used for the port Q as well. The system consist of a cross over pipe to the port Q tank and is, in addition to blowing, used for venting the Qs inside the submarine via silencer as well. The port Q has a separate Kingston (flood valve).
Tore

tore · « **Reply #3092 on:** 16 Sep , 2016, 03:09 »

Karel.
I discovered you ask me a question in another thread on canning. I guess you asked for the image of U 995 taken May 1945 in Trondheim. Below is same and practically no visible canning occurs in spite of a heavy war duty for almost 2 years in the Barentz Sea.
Tore

karel · « **Reply #3093 on:** 16 Sep , 2016, 03:27 »

Quote from: tore on 16 Sep , 2016, 03:09

Karel.
I discovered you ask me a question in another thread on canning.

Tore.
It probably was not me asking that. I have only been active in this thread.

About q tank floodvalve. You mentioned that similar valve was at the port side. I added a screenshot. Is this the valve for port Q tank flood?

tore · « **Reply #3094 on:** 16 Sep , 2016, 04:35 »

Karel.
Although the image is a bit dark but it looks like the port Q kingston. I am posting a new image showing the Q pipe/ valve arrangement at port side next to the chart table.
Tore

VIC20 · « **Reply #3095 on:** 16 Sep , 2016, 05:57 »

Tore, could you explain how the light panel works and how its appearance change when in use?

karel · « **Reply #3096 on:** 16 Sep , 2016, 06:06 »

Yes, that was the one. Thank you. So i now have the handwheel and lever locations tanks 1,5,3,2-4 stb&port,Q stb&port.

I am looking trough 360 panorama pictures and seeing tons of unidentified handwheels. I attached the screenshot, this one seems important due to its size. Very near to observation periscope. Do you know what it is for?

Also i realise that there is a good possibility that you may have already discussed this information with others to a great detail and with illustrative pictures. If this is so, and you still have these pictures which i cannot access due to forum crash then feel free to upload these again. I would love to take a look at them and learn as much as possible.

maillemaker · « **Reply #3097 on:** 16 Sep , 2016, 06:51 »

Hi Tore,

I'm not seeing a picture for the oilcanning reply.

These responses are so awesome! Thank you for telling us all about these u-boats!

I have another question:

On the Revell model, on the bottom of the saddle tanks there are two rows of 4 framed panels of some kind. I am guessing they are drains of some kind for the saddle tanks.

I don't know if you know what these look like since they were usually underwater.

Should they be grills or something? I've seen some modelers make them as grills and others just leave them filled in as they come on the kit.

Revell shows one grilled opening right next to them so if they were grilled I am surprised Revell did not mold in grill detail. Perhaps they are copying U-995 in its restored state and maybe at Laboe they just covered the grills over.

Steve

maillemaker · « **Reply #3098 on:** 16 Sep , 2016, 06:52 »

Hi Karel,

What game are you working on? Is it the new multi-player one they are talking about over on subsim?

Steve

VIC20 · « **Reply #3099 on:** 16 Sep , 2016, 07:42 »

I think he is working on completely different game for the Rift, at least that was what he showed me 2 years ago. (If he is the same Karel who contaceted me)

karel · « **Reply #3100 on:** 16 Sep , 2016, 08:00 »

Hi Mark

Yes, that is me who contacted you years ago. Still hard at work and can really relate to you as i see how gigantic work this is to make a submarine game.

Hi Steve.
I am working on different game but since the guys who are making Marulken recently pivoted and started working on German U-boat then our game will probably have similarities and overlapping features.
Here is a year old article about hands on for our game vr demo. http://www.theriftarcade.com/hands-on-with-displacement-theory/

tore · « **Reply #3101 on:** 16 Sep , 2016, 08:15 »

Quote from: VIC20 on 16 Sep , 2016, 05:57

Tore, could you explain how the light panel works and how its appearance change when in use?

The light panels serves two purposes the upper indicates by light and text if the most important hullvalves are open or shut. The lower panel is a report panel from the various compartments if they are ready for diving. I am not 100% sure which lamp refer to which compartment except engine room and conningtower.
Tore

tore · « **Reply #3102 on:** 16 Sep , 2016, 08:41 »

Quote from: maillemaker on 16 Sep , 2016, 06:51

Hi Tore,

I'm not seeing a picture for the oilcanning reply.

These responses are so awesome! Thank you for telling us all about these u-boats!

Steve.
The images you are showing are the kingstons on the saddle ballast tanks 2 and 4. The inlet with a grating is the kingston ( floodvalve ) for the Q tanks.
(untertriebzelle).See my image below and ask questions if any. For a model I believe it is probably correct to leave them open as can be seen on my model the should not have a grill.
Tore

I have another question:

On the Revell model, on the bottom of the saddle tanks there are two rows of 4 framed panels of some kind. I am guessing they are drains of some kind for the saddle tanks.

I don't know if you know what these look like since they were usually underwater.

Should they be grills or something? I've seen some modelers make them as grills and others just leave them filled in as they come on the kit.

Revell shows one grilled opening right next to them so if they were grilled I am surprised Revell did not mold in grill detail. Perhaps they are copying U-995 in its restored state and maybe at Laboe they just covered the grills over.

Steve

Quote from: maillemaker on 16 Sep , 2016, 06:51

Hi Tore,

I'm not seeing a picture for the oilcanning reply.

These responses are so awesome! Thank you for telling us all about these u-boats!

I have another question:

On the Revell model, on the bottom of the saddle tanks there are two rows of 4 framed panels of some kind. I am guessing they are drains of some kind for the saddle tanks.

I don't know if you know what these look like since they were usually underwater.

Should they be grills or something? I've seen some modelers make them as grills and others just leave them filled in as they come on the kit.

Revell shows one grilled opening right next to them so if they were grilled I am surprised Revell did not mold in grill detail. Perhaps they are copying U-995 in its restored state and maybe at Laboe they just covered the grills over.

Steve

tore · « **Reply #3103 on:** 16 Sep , 2016, 08:46 »

Steve
The photo of the U 995 May 1945 showing the hull without any significant canning is below I guess it has vanished on other posts
Tore

maillemaker · « **Reply #3104 on:** 16 Sep , 2016, 08:49 »

Hi Tore!

So the Kingston valves are basically big flaps, and on the ones on the saddle tank they open inwards, and on the bottom they open outwards?

So if they were closed, then the Revel kit should be fine as-is, I think.

That is great news - I saw one model builder's page where they had gone to great effort to make the Kingston openings on the saddle tanks have grills made from wire to look like the Q Inlet Valve.

See about half-way down this page: http://u-552.blogspot.com/2008_02_01_archive.html

Glad I don't have to do that!

Karel: Your video demo looks great! I would love a Silent Hunter game with those kinds of graphics and interaction!

Steve

maillemaker · « **Reply #3105 on:** 16 Sep , 2016, 08:51 »

Hi Tore,

Thanks for the non-canning photo.

Sadly I have already followed many other modelers on my hull and completed this effect. However I was already aware of your comments on it so I tried to go lightly.

You can see my build progress here:

http://www.shipmodels.info/mws_forum/viewtopic.php?f=28&t=163319

Steve

tore · « **Reply #3106 on:** 16 Sep , 2016, 14:21 »

Karel.
The black valvewheel close to the navigation periscope belongs to the shut off valve of the schnorchel exhaustmast system.
When the schnorchelmast was installed they used the ballasttank exhaustblowing pipe as the schnorchel outletpipe. branching off directly before the exhaust blowing panel outside the pressurehull. The branch pipe goes up above the casingdeck following the towercasing and ends in the schnorchelmast shut off valve having a valvspindle down in the controlroom connecting to a black valvewheel as shown on your image. Again I have to use one of Simon Moriss excellent drawings to illustrate the system. The other smaller black wheel next to the periscope is the locking pin wheel for the schnorchel mast homing on the tower casing.
This pipe on the deck is often forgotten by the modelbuilders as it is not incorporated in the Revell kit
Tore.

maillemaker · « **Reply #3107 on:** 16 Sep , 2016, 14:47 »

I think I have downloaded this "working drawing V05.pdf" - can't remember the guy's username.

Ah, yes, it is Simon Morris' drawing.

But I only see a top view.

Is there a way to get a side view?

Steve

VIC20 · « **Reply #3108 on:** 16 Sep , 2016, 14:57 »

Simons username is usually NZsnowman (his profession is snow & avalanches)

tore · « **Reply #3109 on:** 16 Sep , 2016, 15:04 »

Steve.
I believe the lower part of Simons image shows the side view, including the exhaust blowing panel valvewheels and the schnorchel shut off valve wheel in the controlroom.
Tore

maillemaker · « **Reply #3110 on:** 16 Sep , 2016, 21:23 »

Quote

Steve.
I believe the lower part of Simons image shows the side view, including the exhaust blowing panel valvewheels and the schnorchel shut off valve wheel in the controlroom.
Tore

Hi Tore,

Yes, I see that. I am talking about his entire drawing of the uboat. I have downloaded a PDF (version 5) of his drawings, but when you open it all I see is a top view.

From your picture, I gather there is also a side view. I'm wondering how to access that - is it in the same PDF file or is it a different one?

Thanks,

Steve

maillemaker · « **Reply #3111 on:** 16 Sep , 2016, 21:39 »

Hi Tore,

I have been looking at this picture and I have just realized from your version of it that what I thought was the snorkle head is actually the hydraulic cylinder; the snorkle is actually either raised or missing in this picture:

I have drawn a dotted outline where the snorkle would lie when lowered.

My question is: The lateral braces that I have drawn arrows to - I assumed that these were the deck support struts/braces.

But there is no cutout for the snorkle!

So instead, are these braces below deck, running from the top of the port saddle tank to the top of the starboard saddle tank?

Are these braces what the snorkle lies on when lowered?

It is hard to see the perspective here.

If I am seeing correctly, the casing is missing above the saddle tanks. It appears to be cut off just behind the life raft cannisters.

So I think the braces we see from the life raft canisters forward are for the wooden deck, but the braces we see aft of there are below-deck.

But maybe this is just an illusion and I can't see the casing over the saddle tanks because it is being viewed edge-on.

But if the braces are for the deck, how does the snorkle get through them to lie down?

The more I look at it (follow the starboard side of the deck line) it looks like the casing over the tanks is in fact there.

So if all those horizontal braces are at deck-height, how does the snorkle lie down?

Thanks,

Steve

tore · « **Reply #3112 on:** 17 Sep , 2016, 00:14 »

Steve.
I should not go into details of the image you are referring to as it shows the U 995 in Kiel during the first stage of the rebuild and to me it looks as if the girders and deck beams are of wood. The Germans ripped of the old original Schnorchel arrangement and installed a different type of schnorchel making a mock up of a raising cylinder etc. Below is a cross section view located at frame 55 about the area above COs cabin. I guess it gives a good impression of the casing sidesupports as well as the flood slit and knee plates between the casing side and saddle tank.
Tore

tore · « **Reply #3113 on:** 17 Sep , 2016, 01:25 »

Steve.
Simons drawings isa massive job which I guess would still take years to finish. I don`t think he has a complete sideview of a VIIC as yet. Below is an image, not complete, which I got so far.
Tore

maillemaker · « **Reply #3114 on:** 17 Sep , 2016, 12:06 »

Thanks, Tore, great stuff. Thanks for the clarification on the snorkel.

I have done mechanical design work for 20+ years, using 3D CAD software. In fact I currently work for Solid Edge, a leading maker of CAD software.

Simon's drawings are fantastic, but it breaks my heart to see that much effort put into a 2D drawing when an actual 3D model could have been made instead.

Imagine the potential! Accurate computer game/simulation models. The ability to 3D print actual scale components of a uboat for model making at any scale you desired. The ability to make cross-sectional views at any desired point.

Perhaps some day another Simon will come along and do it in 3D.

Steve

VIC20 · « **Reply #3115 on:** 17 Sep , 2016, 12:45 »

Simon already works on the 3D model.

maillemaker · « **Reply #3116 on:** 17 Sep , 2016, 21:43 »

I'm glad Simon is working on a 3D version!

Tore:

I have updated my build progress here:
http://imgur.com/a/Z6K9m

I have laid in saddle tank extensions (which will be trimmed back greatly) and crafted a false pressure hull roof. I did not go to the trouble to model the sharp ramp transition from the saddle tank down to the pressure hull. I did not feel it worth the effort for the little view through the snorkel slot.

At the front of the Revell snorkel "box" there is another solid area where the head of the snorkel would rest. I have also removed all of that so the entire opening gives a straight shot down to the saddle tanks/pressure hull.

Does this look acceptable?

Thanks,
Steve

tore · « **Reply #3117 on:** 17 Sep , 2016, 23:57 »

Steve.
I guess your schnorchel recess is OK. There are of course limits how far you want to go as to the details using a commercial kit, the Revell kit is not accurate in the details. For instance the anchorbay is, if not corrected on the newer kits, too far aft, the consequence would be the anchor is hitting the fore stb. hydroplane when lowered. I am afraid it is too late for a correction on your model. However the flood gates as we consider are the fingerprints of a VIIC can be corrected. The most significant would probably be the fore flood gates of the peaktank which on the real VIIC are asymetric as there are two on the stb. side and three on the port, not three on each side as on the kit. As for the ejector drains may be you should drill the holes in the aft end. Otherwise there are small deviations to various details depending on at which yard and year the Uboat was built.
Tore

maillemaker · « **Reply #3118 on:** 18 Sep , 2016, 11:06 »

Hi Tore,

Thanks for the comments!

Yes, there are many details that I have seen people do, like moving the anchor bay forward as you note. Fairly significant surgery that requires re-adding rivets, etc.

I may plug the flood as you indicate on the starboard side, as that is pretty easy to do.

My intent with this kit is to build it fairly out-of-the-box (hah, famous last words). I do not want to go too crazy with modifications and/or upgrades. I burned out of model making 20 years ago when I kept raising the bar higher and higher to where I could never undertake anything because it was too overwhelming.

I'm probably going to display this as a "generic" VIIC/41 rather than label it as a specific uboat. This gives me some "out" for inaccuracies.

What do the ejectors eject?

Steve

tore · « **Reply #3119 on:** 18 Sep , 2016, 13:05 »

Steve.
I see your point of view but you are nevertheless deviating from the box with regards to the schnorchel casing recess, in that case I would perhaps make the schnorchel lay- out correct as well, adding the missing deck exhaustbend and schnorchel shutoff valve both very visible on the stb front side of the tower casing, se my image below.
As to the ejector draining, there are very narrow free flood areas between the casing and the pressurehull, aft of MBT 5, marked blue on my image. When diving, a submarine should not leave a trail of bubbles on the surface thus you want to get rid of the trapped air in the void spaces as quick as possible. I guess the "blisters" on both side next to the difficult areas are creating an ejector suction effect to fill difficult the free flood area with water when diving eliminating the bubble trails.
Tore

maillemaker · « **Reply #3120 on:** 18 Sep , 2016, 13:36 »

Quote

I see your point of view but you are nevertheless deviating from the box with regards to the schnorchel casing recess, in that case I would perhaps make the schnorchel lay- out correct as well, adding the missing deck exhaustbend and schnorchel shutoff valve both very visible on the stb front side of the tower casing, se my image below.

Yes, having seen this snorkel detail from the Simon's drawings you posted, I think I am going to attempt to add it. It does not look terribly difficult.

Steve

maillemaker · « **Reply #3121 on:** 19 Sep , 2016, 07:08 »

Here is one fellow's work at moving the anchor well forward 7mm:

http://u-552.blogspot.com/2008/01/anchor-well.html

This is major surgery to the hull and would obliterate a lot of detail that would have to be added back in. I'm going to live with the stock location.

Steve

tore · « **Reply #3122 on:** 19 Sep , 2016, 07:58 »

Steve. The correction wasn`t too bad, I did it on my model. Below is a photo I made during drydocking of KNM Kaura ex U-995 in 1954 when we "dropped the anchor" for inspection which illustrate the chain well clear of the stb. forward hydroplane guard.
Tore

Don Prince · « **Reply #3123 on:** 19 Sep , 2016, 14:17 »

Hello Mr. Tore,

Here is what the bow section of my 1/32nd scale (about 7 feet in length) OTW U-96 looks like...

Regards,
Don_

Don Prince · « **Reply #3124 on:** 19 Sep , 2016, 15:33 »

The U-96 tower is made from brass plate and brass rods - only the seats and and attack periscope shear are from resin. It took over a week shaping the brass plate and using a butane torch to solder all the parts together. The kit only included two flat brass tower sides and the two piece tower deck. The rest of the parts had to be hand made by the builder (me)!

Regards,
Don_

tore · « **Reply #3125 on:** 19 Sep , 2016, 23:32 »

Don.
Have you any idea how many hours you used building this model? It is huge what would the weight be?
Tore

Don Prince · « **Reply #3126 on:** 20 Sep , 2016, 01:42 »

Hello Mr. Tore,

It took 2 years of every other weekend and 2 years of my 5 weeks of vacation. I figure about 1,400 hours and I will attach some building photos...

Regards,
Don_

Don Prince · « **Reply #3127 on:** 20 Sep , 2016, 01:54 »

again

Don Prince · « **Reply #3128 on:** 20 Sep , 2016, 01:58 »

The last photo shows the brass nuts holding the brass forward hydroplane to the hull. Originally the fairings has only studs. I threaded the studs and bolted the fairings into place and then covered the nuts with fiberglass resin to perminately seal everything into place..

tore · « **Reply #3129 on:** 20 Sep , 2016, 03:46 »

Don. You are a true U boat enthusiast having the stamina to spend almost every week end and vacation on a model project for two years.
Seeing the shiny brass propellers reminds me of the VIIC propellers which I guess up 1942 were of a propeller brass alloy, afterwards the VIIC propellers were made of a special steel. Submarine propellers are a special science, the VIIC propellers were not of a particular advanced design, they were susceptible to cavitation on the tip of the blades as well as towards the boss. The pittings were bad, but cavitation is noisy due to the implosions of the vapour bubbles.
Tore

Don Prince · « **Reply #3130 on:** 20 Sep , 2016, 20:15 »

Hello Mr. Tore,

Several years before building U-96, I built a Me 109 Messerschmitt (48 inch wing span - 5 weeks to build) and a Focke Wulf 190A (54 inch wingspan - 6 weeks to build). Both aircraft are made from pieces of white aspen wood (no knots) and not a kit; just weeks of sanding (scratch built)...

I was very interested in aircraft form my teen-age years until 2003; when I got interested in U-Boats. A Long time ago, I had a private pilot license and taught aeronautics to high school kids at the Civil Air Patrol when I was a college student. Going to work for the NCR Corporation and computers changed all that because I had to support a family.

Regards,
Don_

karel · « **Reply #3131 on:** 21 Sep , 2016, 02:41 »

Quote from: tore on 16 Sep , 2016, 14:21

The other smaller black wheel next to the periscope is the locking pin wheel for the schnorchel mast homing on the tower casing.

Tore. The other black wheel that you mentioned. I tried to locate it on panoramic pictures. I found bunch of black wheels near the periscope. Can you identify their purpose? Are they all tied to schnorchel mast control system?

Many thanks.
Karel

tore · « **Reply #3132 on:** 21 Sep , 2016, 09:12 »

Karel.
Identification control room valves. Below is an image which I guess should be the relevant valves.
Tore

Don Prince · « **Reply #3133 on:** 21 Sep , 2016, 09:20 »

Hi Karel,

In addition - These are the images that Mr. Tore provided to me a while back.

Regards,
Don_

maillemaker · « **Reply #3134 on:** 21 Sep , 2016, 20:24 »

I have used a detailed Type VIIC schematic on the web to show what the keel looks like behind the bottom floods at the bow of the boat:

I used this to make a template to make a matching piece to put into the hull of my model.

I am looking for something similar for the stern floods.

Does anyone have a suitable picture?

Thanks,

Steve

tore · « **Reply #3135 on:** 22 Sep , 2016, 01:10 »

Steve.
I don`t think the VIIC has much of a keel in the aft end, the keel begin at about frame 14. Aft of that a double skin hull takes over before it gradually is transferred into a skeg. May be my images below gives an indication. A detail which seems to be forgotten by everybody is the zinc anodes which are protecting the area from galvanic corrosion. You might see the steel fixing straps on the A brackets. The zinc anodes were only plates of zinc app. 20x35 cm 20-30 mm thick fixed to the propeller A brackets as sacrificing elements for the galvanic corrosion.
Tore

maillemaker · « **Reply #3136 on:** 22 Sep , 2016, 11:36 »

Ah-ha, but your blueprint does show the frame/baffle with holes in it above the skeg.

The schematic I was looking at does not show it:

http://files.balancer.ru/forums/attaches/2013/03/31-3107743-planstypeviic.jpg

But yours does - do you have a larger version of your schematic?

Thanks,

Steve

maillemaker · « **Reply #3137 on:** 22 Sep , 2016, 11:42 »

This is the piece I need to create:

Steve

tore · « **Reply #3138 on:** 22 Sep , 2016, 14:29 »

Steve.
May be one of Simons excellent drawings would clarify the matter.
Tore

maillemaker · « **Reply #3139 on:** 22 Sep , 2016, 17:35 »

Hi Tore,

Unfortunately, Simon's drawing does not show the central keel baffle that is in your schematic above.

You can see where I highlighted it here:

Steve

Don Prince · « **Reply #3140 on:** 22 Sep , 2016, 22:02 »

Will this help?

Regards,
Don_

tore · « **Reply #3141 on:** 23 Sep , 2016, 01:29 »

Steve.
I guess I finally understand your question. I don`t think it is an alongship bulkhead in the skeg, only atwartship frames and skin. What you see on my crossection drawing is an indication for a doubler in the way where you have support for the propellers-, rudders- and hydroplanes- guards. I guess Simon has indicated the doublers very well on his drawing.
Further you`ll see the crank for the aft hydroplanes operation is fitted in the center of the skeg.
Tore

maillemaker · « **Reply #3142 on:** 23 Sep , 2016, 06:08 »

Hi All,

What I am trying to do is make the section of the keel that is behind the lower floods, fore and aft. I have achieved the forward ones.

This is the effect I am trying to duplicate, from another modeler:

In Tore's earlier post he showed this picture:

In this image, on the aft end of the pressure hull, both above and below you can see a frame with flood holes in it, presumably along the centerline of the hull.

I have highlighted it in this close-up of the same image here:

The purpose of this detail on the model is simply to make it so you don't see straight through the floods from one side of the ship out through the other side without seeing a mock-up of the internal structure of the ship.

All subsequent schematics posted do not show this detail.

Perhaps it is not really there?

I believe at this point I will simply fake something in; the detail is not actually important as no one will be able to directly see it.

Steve

tore · « **Reply #3143 on:** 23 Sep , 2016, 06:40 »

Steve.
You are not the first one who makes effort in preventing that you should not "see through the free flood gates. For some reason there are aversions to this possibility. The fact is you are able to "see trough" on the real VIICs as there are no center bulkheads, so why make up something which are not there in real life? You should never copy the details on the museum U 995, but in this particular case you may, see my images of the area below, on one of the original photos you are actually able to see through the freeflood area.
Tore

tore · « **Reply #3144 on:** 23 Sep , 2016, 07:37 »

Steve.
My image showing a longitudenal cross section of the stern is probably not a very good one as the doubler is drawn as a square box which might be mistaken as a floodhole. However Simons drawing is correct and he has drawn the doublers as they looks. A doubler is an additional steelplate riveted in places to increase the strength locally, in these cases to support the propeller-,hydroplane- and rudder guards connection to the hull.
Tore

maillemaker · « **Reply #3145 on:** 23 Sep , 2016, 08:34 »

Hi Tore,

The issue is not being able to see through the floods, but to see through unobstructed. There should be something seen partially blocking the view if you look through the floods.

However, looking again at your picture, the piece that is missing from Simon's drawing may be above the floods anyway.

Though it is not clear to me what this framing structure would rest on if it does not go all the way to the keel. It would be like a "fin" welded to the aft end of the pressure hull attached to...what?

Steve

Don Prince · « **Reply #3146 on:** 23 Sep , 2016, 11:54 »

Hi Steve,

I believe you are looking at stringers with holes (baffles) which are internal to MBT 1. So I believe Simon's drawing is correct (but doesn't show the lower internal stringer) and Mr. Tore pointed out the heavy metal strip which the post was attached.

maillemaker · « **Reply #3147 on:** 23 Sep , 2016, 12:12 »

Oh, I think I see what is going on here now.

These stringers are not on the vertical cross section of the hull.

It looks like they are at an angle.

So instead of going straight down from the pressure hull to the keel, they go radially out from the pressure hull to, it seems, the outer hull, intersecting just above the floods.

I think this is the correct interpretation?

So there appears to be nothing in between the floods looking straight across the hull. So the previous modeler's interpretation was incorrect.

Thanks,

Steve

tore · « **Reply #3148 on:** 25 Sep , 2016, 08:44 »

Steve.
May be my image below illustrates how the double skin hull is attached to the pressurehull, the image is of a IXC but the system is the same as on the VIICs.
I don`t think there are any floodholes in the skeg.
Tore

SnakeDoc · « **Reply #3149 on:** 25 Sep , 2016, 14:31 »

Hi Tore,

regarding the discussion about type IXC buoyancy tanks in the next thread, I would like to ask you, how these tanks were used on KMN Kaura? Did you cruise at surface with tanks flooded or blown? Or depended it from the sea state?
If flooded, with vents permanently opened?

--
Thanks, regards
Maciek

Don Prince · « **Reply #3150 on:** 25 Sep , 2016, 21:53 »

Hi Steve,

In my humble opinion - I think the skeg keel has a heavy metal lower base where the metal vertical rudder protection structure is attached besides the hydroplane drive shaft and the dual prop support. The skeg keel only has internal vertical frames and flooding holes on each side. There are no stringers internal to the skeg keel... It looks to me that Stringer #1 is only internal to MBT 1 and attached to the aft pressure hull.

The 1st image Stringers 1 shows stringer #1 and it looks to be at an angle (possibly several stringer #1's). The 2nd image MBT 1 shows a vertical slice of the U-Boat at frame +2 and the stringers are all internal to MBT 1, and at frame -6 there are no stringers visible.

I hope this helps,

Kind regards,
Don_

tore · « **Reply #3151 on:** 25 Sep , 2016, 23:44 »

Maciek.
The buoyancy tanks did not participate in the surfacing procedure as they are primarily used to improve surface buoyancy to prevent ( bow tank) undercutting. To a certain extent there are selfdraining (more timeconsuming than blowing) as the tank is situated above the surface. When pitching I guess the waterlevel in the tanks pulsated thus compressing the air in the tank.
Tore

maillemaker · « **Reply #3152 on:** 26 Sep , 2016, 07:49 »

Quote

In my humble opinion - I think the skeg keel has a heavy metal lower base where the metal vertical rudder protection structure is attached besides the hydroplane drive shaft and the dual prop support. The skeg keel only has internal vertical frames and flooding holes on each side. There are no stringers internal to the skeg keel... It looks to me that Stringer #1 is only internal to MBT 1 and attached to the aft pressure hull.

The 1st image Stringers 1 shows stringer #1 and it looks to be at an angle (possibly several stringer #1's). The 2nd image MBT 1 shows a vertical slice of the U-Boat at frame +2 and the stringers are all internal to MBT 1, and at frame -6 there are no stringers visible.

Hi Don,

Yes, the images you have posted are quite helpful.

Stringer #1 is what I was after.

From the images you have posted, I believe that Stringer #1 does not lie on the centerline of the boat. It probably radiates away from the pressure hull to the outer hull at angles, probably roughly in-line with the prop shaft supports, as I had previously guessed and illustrated here:

I think thiis is corroborated by your image:

So the stringer #1 that I thought I was seeing in vertical section as lying on the section plane is actually placed radially out from the pressure hull.

This means that the skeg is hollow and there seems to be nothing in between the floods on one side of the boat to the other.

The modeler I was following on the U552 blogspot site was incorrect.

I think I understand now.

Steve

maillemaker · « **Reply #3153 on:** 26 Sep , 2016, 10:08 »

From another thread:

Quote

Hydroplanes.
The forward hydroplanes have no connection to the outer part of the hydroplaneguards. On many drawings it looks indeed as if there is a throughgoing shaft ending up in the hydroplane guard, however the hydroplane shaft end up in a fixing point about half way into the hydroplane, I guess you`ll find a bolted accesshatch at the fixingpoint.
The aft hydroplanes are slightly different although the shaft and fixingpoint are the same there is a small connection to the guard at the outerpoint. As far as I remember it is not a support shaft and bearing at the point rather a small bar shutting the gap to prevent ropes or other objects to enter the propellerarea.
The jumping wire on the fwd hydroplane guard was removed sometimes I guess at the time when the netcutters were removed. This reminds me of an event we had near Scapa Flow when we anchored waiting for orders over the night. In the morning raising the anchor we experienced the anchorcable was stuck between the forward hydroplaneguard and the hydroplane. We had to free dive in the cold November sea (wearing longjohns) to release the cable.

So, I gather that the guard on the front hydroplanes should not physically attach to the hydroplane itself?

Also, the guy wire running from the hydroplane guard to the hull was ommitted about the time the net cutters were removed?

I have a question about the radar. Did it emit harmful radiation to the watch crew?

Steve

tore · « **Reply #3154 on:** 26 Sep , 2016, 11:30 »

Steve.
Below are the images of the fore hydroplane as you see no connection with the guard, contrary to the aft having a nut. Yes I guess they did away with the wires around end 1942.
Tore

tore · « **Reply #3155 on:** 26 Sep , 2016, 11:39 »

We did not use the radar very much as it wasn`t any good. To my knowledge nobody was hurt by radiation.
Tore

maillemaker · « **Reply #3156 on:** 26 Sep , 2016, 12:26 »

Quote

We did not use the radar very much as it wasn`t any good. To my knowledge nobody was hurt by radiation.

But the watch crews had uncanny eyesight after their third eyes grew in!

Steve

Don Prince · « **Reply #3157 on:** 26 Sep , 2016, 13:54 »

Hi Steve,

I believe you've got it... The one thing I had a hard time understanding at first was MBT 1 (AFT) and MBT 5 (fwd) were designed very similar to the saddle tanks (MBT 2 and MBT 4) and all being exterior to the pressure hull. Where the U-Boat's outer sheet metal casing is the ballast tank's exterior. In the lower drawing, the frame that makes a full loop is inside the interior of MBT 1, and the U-Boat's sheet metal outer skin/casing is the exterior of MBT 1. When I first started studying the Type VII C U-Boat, I had in mind that MBT 1 and MBT 5 were ballast tanks inside the exterior hull casing. The only tank that is different is MBT 3 where this tank is inside the pressure hull under the control room floor. However, the lower portion of MBT 3 is the pressure hull which is the under belly of the U-Boat's exterior mid-section.

If I have made any incorrect statements, then I sure hope Mr. Tore or Maciek will jump in and correct me on this subject because I'm still learning from these gentlemen!

Kind regards,
Don_

tore · « **Reply #3158 on:** 26 Sep , 2016, 23:27 »

Don.
No need to jump in. The lower aft part of the skeg has space for the the pull/push rod, crank and fulcrum shaft bearings for the aft hydroplanes operation being able to move 30 degrees up and down.
Tore

tore · « **Reply #3159 on:** 28 Sep , 2016, 04:29 »

Studying the many photos of the aft part of the skeg I guess it is possible that this is cast steel riveted to the outer hull by a double row of rivets. The casting incorporate the support for the aft hydroplanes fulcrum shaft as can be seen on the image below.
Tore

Don Prince · « **Reply #3160 on:** 29 Sep , 2016, 18:08 »

Hello Mr. Tore,

When you surface a U-Boat one diesel is used to power the U-boat on the surface... I guess the 2nd diesel is used 1st to exhaust blow the ballast tanks, and then charge the batteries. Is it possible to do both at the same time with the 2nd diesel?

Regards.
Don_

tore · « **Reply #3161 on:** 30 Sep , 2016, 00:29 »

Don.
The possibility exsist, adjusting the charging load, I would probably prefer to put the charging on the propulsion engine shaft. When blowing the ballastanks by diesel exhaust the ruling factors are the bmep ( break mean effective pressure)and exhaust backpressure as one diesel is producing ample volum for blowing the tanks. The total exhaust backpressure is constantly monitored by an engineer in the engineroom keeping an eye on the exhaustmanometer and adjusting the pressure by the outer group exhaustvave designed for the purpose. The bmep is monitored by an engineer at the engine maneuvring stand. The distribution and pressures for the induvidual tanks are monitored by the controlroom engineer at the exhaust control panel. If for some reason the pressure becomes too high there is a reliefvalve on the engine exhaustmanifold which release the exhaust into the engineroom. I have experienced that a few times and it is very unpleasant.
Tore

karel · « **Reply #3162 on:** 04 Oct , 2016, 10:24 »

Tore

Do you if there is any source online where i could locate the lighting of the boat? I am looking trough museum panoramic pictures and am able to see lightbulbs but they seem to be too few in numbers. They have been probably removed. I would like to keep my lightbulbs more or less at the same places where they were originally.

tore · « **Reply #3163 on:** 05 Oct , 2016, 00:39 »

Karel.
Unfortunately I have no cabling plan or images of all the original accommodation lamps/bulbs of the U-995. My best advice would be to look at the various images particularly the kubische panorama.de of the U 995 at Laboe. The museum boat has of course different lights and modern cabling racks as can be seen on my image below. The orgininal fittings are shown as well. Note the lightbulbs had a thick glassprotection as shown.
Tore

tore · « **Reply #3164 on:** 09 Oct , 2016, 01:18 »

Karel.
Following up your VIIC lampquestions. A few lamps had lampshades, like in the wardroom, CPTO mess and PO mess.The Bavarian Filmstudioes made a good research on the lamps, shades and colours for the execellent movie das Boot. Below is an image showing the various lamps.
Tore

maillemaker · « **Reply #3165 on:** 10 Oct , 2016, 11:52 »

In 'Das Boot' during the Alarm they the crew is shown running forward and swatting a hanging light/shade out of the way. I was amazed that it could tolerate that without blowing the bulb or damaging the cable.

Realistic?

Steve

tore · « **Reply #3166 on:** 10 Oct , 2016, 14:12 »

Steve.
Battlestations or divingstations as we called it, would generally imply mostly people moving from forward compartment to aft. This would mean the officer on watch would give the order to the trim man prior to the divingstation order:" pump 400 liters from aft to fore". When you heard that order you would anticipate the next order:" divingstation". In the CPTOs mess and the wardroom you usually could hear pretty much of the orders given in the controlroom and the lamps in the CPTO,and PTO messes were usually moved to the side, in the wardroom the passageway was on the stb side leaving the lamp hanging over the table undisturbed. When the order was given, contrary to the Movie, the rush of people was not as noisy and dramatic. But of course the movie people wanted to have some drama.
Tore

maillemaker · « **Reply #3167 on:** 11 Oct , 2016, 13:18 »

Quote

Battlestations or divingstations as we called it, would generally imply mostly people moving from forward compartment to aft.

Hi Tore,

I assume you mean people moving from aft compartment to forward?

Steve

Don Prince · « **Reply #3168 on:** 11 Oct , 2016, 14:39 »

Hello Mr. Tore,

I'm having an issue about (rethinking) how to describe the ballast tanks...

In the type VII U-Boat the forward, center, and aft tanks are described as Tauchzelle or diving cells, and the saddle tanks are described as Tauchbunkers or diving bunkers.

Diving cells are strictly water ballast tanks, and diving bunkers are configurable to a reserve fuel oil (RFO) or a water ballast.

When did these tanks become Main Ballast Tanks and labeled MBT 1, MBT 2, MBT 3, MBT 4, and MBT 5? Was this done in translation to eliminate the confusion between the Gerrman diving cells and diving bunkers?

Which is correct?

Regards,
Don_

tore · « **Reply #3169 on:** 12 Oct , 2016, 00:04 »

Steve.
The largest accommodation for the crew was the fore torpedoroom having 12 fixed bunks as well as hammocks, the majority of these people had their divingstations aft of the accommodation. The officers and CPTOs had their divingstations aft of their accommodations as well and even most of the PTOs, engineers and electricians had to move aft , to the engineroom and E room, hence the the trim of the boat had to be compensated by a larger trimming moment pumping 400 liters from aft to fwd. trimtank.
Tore

tore · « **Reply #3170 on:** 12 Oct , 2016, 01:09 »

Don
I Guess the RN English nomination derives from the translation done by the RN when they got hold of the VIIC documents during WW2. I am pretty sure the Germans used the expressions mentioned on the original GA drawings. The problem could be that the various tanks were used to a certain extent differently by the German Navy and RN. F. inst the Untertriebzelle in RN English we used the nomination Q tank for quick diving whenever you had to change depth quickly (e.g. not dynamically) as f. inst. in the case you had to avoid ramming. The German used the Untertriebzelle to assist a quick diving from the surface ( to overcome the "surface resistance") and got the name for that purpose, Unter ( under) trieb (force) zelle. The Germans did the numbering for frames, tanks, dieselengine cylinders etc starting from aft we did the opposite. The Germans were not consistant though, as the fore torpedotubes have the nos 1 & 3, 2 & 4 and the aft no 5. It is hard to state what`s correct I Guess describing a german piece of engineering would be using the German system, for a non german speaking english person it might give a better understanding using the RN English. But I really have no idea.
Tore

Don Prince · « **Reply #3171 on:** 21 Oct , 2016, 00:03 »

Hello Mr. Tore,

During a submerged torpedo attack, how many people would be in the tower?

I count three (3)
- the captain
- the helmsman
- and someone to input the TDC data?

Or was that a 2nd job for the helmsman?

Regards,
Don_

P.S. I have until December 1, 2016, to make any changes to Skizzenbuch according to my managing editor. I should be finished in about two weeks with the clean-up and changes and will upload it to dropbox. I believe I should use FBT 2 and 4 instead of MBT 2 and 4 because of the different German wording - Tauchbunker Vs Tauchzellen. The US and British reports on different U-Boats use the FTB term for the RFO or Ballast Tanks...

If you have any suggestions, then please let me know???

Regards,
Don_

tore · « **Reply #3172 on:** 21 Oct , 2016, 00:42 »

Don.
I assume you are referring to submerged launching of torpedoes at periscope depth. We usually had two men in the tower and kept the helmsman in the controlroom. However our CO preferred to carry out most attacks (simulated) from the controlroom as can be seen from the image below.
I guess it is a good idea to change the saddleballasttanks to FBT instead of MBT.
Tore

Don Prince · « **Reply #3173 on:** 21 Oct , 2016, 11:20 »

Hello Mr. Tore,

If it were a submerged torpedo attack and the CO was using the attach periscope in the tower, then there would be another person involved in the operation; a helmsman, the CO, and who would the person be handling the TDC? Who would normally input the info into the TDC on any type of torpedo attach scenario? I thought the No. 1 Officer handled a torpedo attach from the bridge using the UZO... Could they all fit into the cramped tower space, or would the helmsman need to take his station back in the control room?

Regards,
Don_

tore · « **Reply #3174 on:** 21 Oct , 2016, 11:33 »

Don.
I don`t remember 100%, but I Guess the helmsman would be in the controlroom. We very seldom had the helmsan in the tower. He was generally either on the bridge during surface harbourmaneuvre or in the control room.
Tore

NZSnowman · « **Reply #3175 on:** 21 Oct , 2016, 12:13 »

Tore, can you remember how the wooden deck hatches were fixed to the deck so they would not float away?

tore · « **Reply #3176 on:** 21 Oct , 2016, 13:49 »

Simon.
All the wooden hatches had hinges and were locked in place, a typical example is the hatch adjacent to the hydraulic cylinder of the schnorchelmast seen on the images below.( U 968). For the wooden deckhatches connected to the pressurehull hatches was a special arrangement whereby you opened the wooden deckhatch simultaneously with the pressurehull hatch by a system of hingerods as can be seen on the image. Note the wooden deckplanks were bolted to the steel supports shown on the image.

NZSnowman · « **Reply #3177 on:** 22 Oct , 2016, 02:41 »

Quote from: tore on 21 Oct , 2016, 13:49

Simon.
All the wooden hatches had hinges and were locked in place, a typical example is the hatch adjacent to the hydraulic cylinder of the schnorchelmast seen on the images below.( U 968). For the wooden deckhatches connected to the pressurehull hatches was a special arrangement whereby you opened the wooden deckhatch simultaneously with the pressurehull hatch by a system of hingerods as can be seen on the image. Note the wooden deckplanks were bolted to the steel supports shown on the image.

This images has been resized. Click to view original image.

This images has been resized. Click to view original image.

tore · « **Reply #3178 on:** 22 Oct , 2016, 06:04 »

Simon.
I can`t remember the exact details, but below is an image of KNM Kaura 1953 showing some details of the wooden casingdeck hatches may be i can be of some help.
Tore

SnakeDoc · « **Reply #3179 on:** 22 Oct , 2016, 11:12 »

Hi Don,

Quote from: Don Prince on 21 Oct , 2016, 11:20

If it were a submerged torpedo attack and the CO was using the attach periscope in the tower, then there would be another person involved in the operation; a helmsman, the CO, and who would the person be handling the TDC? Who would normally input the info into the TDC on any type of torpedo attach scenario? I thought the No. 1 Officer handled a torpedo attach from the bridge using the UZO... Could they all fit into the cramped tower space, or would the helmsman need to take his station back in the control room?

During submerged attack, the TDC was operated by (Ober)Bootsmann, CO was at the attack periscope. There was space for three men in the conning tower. Between helmsman saddle and attack periscope was hatch to the control room and ladder to the bridge. The TDC operator was on the most inconvinient position.

As you said, IWO was at the UZO sight column duiring surface attack and in the control room when submerged.

--
Regard
Maciek

NZSnowman · « **Reply #3180 on:** 22 Oct , 2016, 12:33 »

Quote from: tore on 22 Oct , 2016, 06:04

Simon.
I can`t remember the exact details, but below is an image of KNM Kaura 1953 showing some details of the wooden casingdeck hatches may be i can be of some help.
Tore

There seen to be a huge variation in deck hatches layout between the boats. I will use the normal layout for U-1308.

Don Prince · « **Reply #3181 on:** 28 Oct , 2016, 00:11 »

Hi Maciek

Damaged Armature and the use of Field Sw-I and Field Sw-II

Skizzenbuck page 398

Would this be accurate?

"The motor on the left is disabled mechanically by uncoupling the direction switch control with field switch I (off position). Two switch commons will be in an open position, while a resistor is used to discharge the shunt windings from MI by a third set of contacts (upper). With this failed condition, the motor on the right MII may only be run in the parallel configuration. However, the thing to remember is both e-motor armatures are housed in the one motor casing and pinned to the same armature drive shaft; one armature is powering the common drive shaft while the damaged armature is free spinning.

Do you know if the direction switch had to be in off position in order to uncouple MI or MII with field switch I or field switch II when an armature was damaged.

The older switchboard they could uncouple the switch blade actuators in any position. However, I'm not sure what they had to do to the wiring for the armature induced current in the shunt windings???

Regards,
Don_

PS - I personally went into the Comcast email and disabled their spam filter, so my Comcast e-mail account should pass any email to my home MS Outlook e-mail account on my system.

SnakeDoc · « **Reply #3182 on:** 01 Nov , 2016, 13:23 »

Hi Don,

Quote from: Don Prince on 28 Oct , 2016, 00:11

Would this be accurate?

"The motor on the left is disabled mechanically by uncoupling the direction switch control with field switch I (off position). Two switch commons will be in an open position, while a resistor is used to discharge the shunt windings from MI by a third set of contacts (upper). With this failed condition, the motor on the right MII may only be run in the parallel configuration. However, the thing to remember is both e-motor armatures are housed in the one motor casing and pinned to the same armature drive shaft; one armature is powering the common drive shaft while the damaged armature is free spinning.

It is ok and accurate. I only wonder if phrase "disabled mechanically" does not suggest that the half of the double-armature motor is mechanically locked.

Quote from: Don Prince on 28 Oct , 2016, 00:11

Do you know if the direction switch had to be in off position in order to uncouple MI or MII with field switch I or field switch II when an armature was damaged.

Well, I'm sure that direction switch should be in off position. However I do not know if direction switch is interlocked somehow with field switches or it is the operator responsibility to switch them while in correct positions.

I rather think that Germans interlocked them in such way that the field switch could be toggled only when direction switch is off. In other case, it could be fatal, when while running both armatures, the field switch was toggled accidentally.

Quote from: Don Prince on 28 Oct , 2016, 00:11

The older switchboard they could uncouple the switch blade actuators in any position. However, I'm not sure what they had to do to the wiring for the armature induced current in the shunt windings???

I have to think about this.

--
Regards
Maciek

Don Prince · « **Reply #3183 on:** 01 Nov , 2016, 14:27 »

Hello Mr. Tore and Maciek,

Thank you for the info about the Field Switches... I have been working on a re-write of several sections of Skizzenbuch (text, photos and drawings), and I still need to verify the text on my 3rd section (I'm about 70% done); there are 5 Word/PDF sections to Skizzenbuch. However, I have re-compiled the DPF files into one document and uploaded what will be presented to my managing editor on December 1st to dropbox. Possibly one more re-compile before Dec 1, if any of the text in section 3 needs to be changed, or if I get any suggestions form you all. I think this process has improved the final product and I took Jak Showell's suggestion and verified all the German text and found several spelling errors on my part.

The latest version "Skizzenbuch 11 x 17 - M + Index.pdf" is available in dropbox...

Regards,
Don_

SnakeDoc · « **Reply #3184 on:** 02 Nov , 2016, 02:32 »

Hi Don,

Quote from: Don Prince on 28 Oct , 2016, 00:11

The older switchboard they could uncouple the switch blade actuators in any position. However, I'm not sure what they had to do to the wiring for the armature induced current in the shunt windings???

I have been analyzing the schematic of the lever switchboard and in my opinion, the Feldschalters in this older type of switchboard do not have the same function as in the rotary type switchboard (i.e. disconnecting field winding while respective armature is damaged).

When I gather my comments and make some sketches, I will post them here.

--
Regards
Maciek

tore · « **Reply #3185 on:** 02 Nov , 2016, 07:13 »

Don.
I have started to look through your latest Skizzenbuch and have some comments to your page 28 plate 6. You have added the english text for the icon of a sea boardvalve as used in the translation from german to english. I guess this might be a bit general for an important valve. The valve a is the main seaboard inletvalve for the trim/regulating and evaporator systems having the standard LPairconnection for seaweed blowing and a branch of to the evaporator valve, a 1, as well as a connection to the finefilling valve, a 1, for the regulating- and trimtanks as can be seen on my image below.
Tore

Don Prince · « **Reply #3186 on:** 02 Nov , 2016, 15:18 »

Hello Maciek,

Page 380 - there looks to be a lock-slide between the Sw1 and Sw2 Direction Switch Assembly. Also, I have attached a photo of the Type IX switch panel where this is visiable...

Mr. Tore, I need time to look at your comments...

I completed the review of section 3 and re-complied and uploaded the latest to dropbox...

Regards,
Don_

SnakeDoc · « **Reply #3187 on:** 02 Nov , 2016, 16:36 »

Hi Don

Quote from: Don Prince on 02 Nov , 2016, 15:18

Page 380 - there looks to be a lock-slide between the Sw1 and Sw2 Direction Switch Assembly. Also, I have attached a photo of the Type IX switch panel where this is visiable

Could you please mark this lock-slide on both drawings? (you can send them to me by email)

--
Regards
Maciek

Don Prince · « **Reply #3188 on:** 02 Nov , 2016, 20:55 »

Hello Mr. Tore,

I added the info you provided on page 31... Re-compiled the book and placed the updated version in dropbox.

Thank you,
Don_

SnakeDoc · « **Reply #3189 on:** 03 Nov , 2016, 01:57 »

Hi Don,

ok, now I know what you mean. Yes, this lock-slide was used to couple direction switches of each armature together, so when the E-Motor was klar, both armatures were powered in the same way. When one armature was damaged, the lock-slide was removed, respective switch was set in the Aus (middle) position, and the other switch could be operated independently.

However, this lock-slide was not coupled with Feldschalters, and I think that these Feldschalters were used during normal operation (not in case of damaged armature). I will post more details soon.

--
Regards
Maciek

tore · « **Reply #3190 on:** 03 Nov , 2016, 03:00 »

Don.
Checked page 31 OK. Page 38 plan7. Your text on plan 7 dealing with the use of Q is a bit unclear and as you have a full description of the use on the following pages it might be an idea to ommit same and give a general description of the Q, may be something like this: The negativ buoyancy tanks stb. and port are located outside the pressurehull in the saddletanks, they are provided to reduce the divingtime. The tanks are pressureproof. Each tank is flooded by a floodvalve operated from the control room. The tanks are vented inside the boat through a common muffler and blown by HP air from the controlroom.
Tore

Don Prince · « **Reply #3191 on:** 03 Nov , 2016, 13:55 »

Hello Mr. Tore,

I made the changes to page 39, page 38 has the discussion about the Manual No. 381 (Tauchvorschrift). I also corrected a spacing problem on page 52 - 4.700m3 to 4.700 m3 - Note, I didn't use the sup option to raise the 3 (cubic) because I can't seem to get out of that option when once in...

I uploaded the updated Skizzenbuch into dropbox...

Regards,
Don_

Don Prince · « **Reply #3192 on:** 04 Nov , 2016, 22:39 »

Hello Mr. Tore and Maciek,

Maciek, I took all your suggestions with reference to the G7e torpedo heating and charging, and the info you provided about the Switchboards...

Pages - Torpedoes
283 - added text
284 added graphic and text
312 - worked on text
314 0 added a paragraph

Pages - Switchboards
Page 378 - changed item (e) Starting Contactor, and (f) Motor Circuit Breaker
Page 379 - corrected labels on drawing
Page 380 - corrected drawing, added a photo and text
Page 381 - corrected drawing added text
Page 390 - Corrected drawing added Starting Contactor and item 1
Page 391 - corrected item 1

I have a question about the photo on page 396 - the items on top of the e-motors are described as converters. However, they do look different. Is the description accurate?

I uploaded the latest version of Skizzenbuch with all of these changes into dropbox. I sure hope I haven't made a mess of things...

Regards,
Don_

Don Prince · « **Reply #3193 on:** 05 Nov , 2016, 02:35 »

Page 380 is wrong!!! I will re-post a update to Skizzenbuch tomorrow...

Don_

SnakeDoc · « **Reply #3194 on:** 05 Nov , 2016, 03:32 »

Hi Don,

Quote from: Don Prince on 04 Nov , 2016, 22:39

I have a question about the photo on page 396 - the items on top of the e-motors are described as converters. However, they do look different. Is the description accurate?

Yes, it's accurate. They look different because they are different type. The converters differs one from another due to different output voltage, frequency (i.e. rotary speed), output power, number of generator windings. All these things cause that the look different.

--
Regards
Maciek

Don Prince · « **Reply #3195 on:** 05 Nov , 2016, 15:52 »

Hello Mr. Tore and Maciek,

Maciek, thank you for the info about the photo of the E-Motors...

I have uploaded Skizzenbuch to dropbox with the fixes to page 380 and hopefully my confusion about un-coupling the speed controller hand wheels is now correct for the Type VII C U-Boat...

Regards,
Don_

NZSnowman · « **Reply #3196 on:** 05 Nov , 2016, 18:31 »

Plate 16: Flooding, venting, low pressure exhaust gas and emergency blowing systems http://www.uboatarchive.net/U-570/U-570Plate16.htm

Hi Tore

I have a few questions:

Valve C - Emergency vent (flap) valve

Is this location within tank?
What does the vent (flap) valve look like?
Does the double line indicated that they handle was inside pressure hull?

Valve M - Drain valves

RFO Tank 1’s & Neg Buoy Tanks, or the open ocean?

Don Prince · « **Reply #3197 on:** 06 Nov , 2016, 01:21 »

Hi Simon,

Here is what I have...

Regards,
Don_

NZSnowman · « **Reply #3198 on:** 06 Nov , 2016, 01:39 »

Quote from: Don Prince on 06 Nov , 2016, 01:21

Hi Simon,

Here is what I have...

Regards,
Don_

Thanks Don.

Do you know if the Valve M - Drain valves, drain into the open ocean?

tore · « **Reply #3199 on:** 06 Nov , 2016, 03:27 »

Simon.
As you know there are extensive ventducts under the casingdeck and for the saddletanks you have even gatevalves in the ducts to be shut from outside the pressurehull when in fuelconfiguration. As the saddletanks venting ducts are interconnected in a stb and port system they are susceptible to damages like shrapnels, machinegunfire etc. If the ducts are damaged you are in fact damaging port or/and stb saddle ballasttanks, hence you have an emergency shutoff valve at the ventduct entrance to the tanks. The emergecy shut off valves are operated inside the pressurehull but as the handlewheels are usually removed they are hard to see. The double line on the plate is indeed indicating the pressurehull.
On some photos you might be able to see the valvespindle and the traditional valveindicator right above the chart table on the fwd. port side of the controlroom,as on my image below.
Tore

Author Topic: Tores mailbox VIIC and VIIC/41 operation and technical details (Read 665866 times)

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