Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

 Jon.
At the time of KNM Kaura the pressurehull was divided in two, the part which was submerged while the submarine was surfaced and thus having barnacles and seaweed growth like a conventional ship.However the saddle tanks were painted black right up to the casing and that was an antifouling painting, approximately each 6 months depending on the growth , resistance and thus speedreduction. Then you had a complete painting of the outside, both pressurehull and casing each 2 years. The ballasttanks and especially ballasttank no. 3 were painted inside with a yellow!! ( yellow submarine? ) anticorrosive  zinc chromate simultaneously or if needed during the 6 monthly inspection. The wooden deck was constantly inspected and painted dark by crew, more for airplanes than need for protection. In fact the German regulations said always to have a dark paint for the wooden deck on board in view of the airsurveillance. The fancy wooden look deckpainting  which some modellers are using is thus not correct, a more dull dark gray almost black, would be more appropriate.
Tore

[Capt Kremin]

Hi Tore
 
Thank you very much for you answer, you have solved a couple mysteries that I have been wondering about.
 
Regards
 
Jon

[NZSnowman]

Tore, after a long time and lots of hard work, I think I have added all the piping under the decking forward of the engine

[tore]

Simon.
No doubt it is a lot of hard work behind this drawing. To have a complete picture of all the systems in a sideview is almost impossible, but after having a quick look it seems you got almost everything in place. Well done.
Tore

[SG]

Tore i would like to ask you 2 questions about life in a type VII u-boat.
- Is it true that humidity and being wet were a constant issue? i mean how dry a crewmember would expect to be on a ordinary day? I've seen the scenes of Das Boot when people rushed back inside from the conning tower and the shower raining from the turret hatch was a constant matter. The film also shows food moulding. Was it all really like that or it used to happen only in long patrols or in particular circumstances, for example extremely bad weather?
- Diesel smell: confined to the engine room or soaking uniforms, berths, food?
thanks in advance
 

[tore]

SG.
First of all Das Boot gives an unprecedented image of the real life in a VIIC. Humidity was a problem. I never took my best uniform on board in spite we sometimes had to entertain guests and attend cocktailparties on fleetvisits abroad. All the stripes and buttons turned quickly green and the cloths got mouldy. For my own sake I solved the the problem in an illegal unconventional way by letting the first electrician installing a 40 watt bulb in my closet to keep my uniform dry. We never used the uniform at sea. This however was the fringe benefit of being the chief engineer and was of course never allowed to be installed for the rest of the crew. The lovely smell of diesel was not confined to the engineroom and I am afraid there was some concentration around my bunk and battledress not food,. Apart from a few drops of water coming from the upper hatch just after surfacing during normal weathercondition it was dry. However in bad weather water would come gushing down like crazy and we very often had to shut the hatch leaving the poor buggars on the bridge to the elements. A few times we had to dive to continue sometimes you could feel the swell at 50 meters.(North Sea). Moulding of the food (bread)happened only during weeks of patrolling  like our longest schnorcheling trip of 28 days.
Tore

[SG]

Thank you very much Tore! the installation of the 40 W bulb was really a great idea!   
Another question: Are the missions/patrols of KNM Kaura still classified? if not: what is the the most risky mission the Kaura has ever undertaken? 

[tore]

SG.
I don`t think anything is classified, more history. Risky missions are not usually planned, they just happens for various reasons. The first risky mission was probably the first dive after being mothballed for several years after WW2. During the first years of the cold war and NATO we thought it would be OK to introduce the 3 VII Cs in our submarinefleet. The VII Cs were stowed away in a Norwegian fjord with very limited drawings and instruction material. The German navy did not exist, thus no possible German info. Old submariners got the job to figure out the details and I am told the first tests were carried out in the harbour of Trondheim with the biggest available harbour crane hook secured to the hull prior to the test dive. Incident occurred and risky situations ,not mission, arise. I have experienced two. During a work up period with fairly fresh crew we should carry out a routine dive and some how the main dieselair inletvalve was not shut, luckily the inletvalve into the engineroom was, but the whole airduct from the conningtower to the engine room was filled with water app. 5 tonnes, creating an unintended deep crash dive which didn`t stop till we were well below 100 meters. A similar situation occurred during a testdive after an annual docking. You always have an accurate weight calculation prior to such a dive to be sure you have the right ballast. No 1 being the responsible officer made a mistake and at the dive we went down like an elevator. The CO very quickly took action and ordered to blow all the tanks but we were so heavy so it took quite some time before we stopped at record depth where we were "hanging" some nervewrecking seconds before we slowly started to climb to the surface. However surfacing by blowing air and not using hydroplanes at depths exceeding 100m creates a jet effect by the expanding air and you shoot out of the surface like a torpedo and hope no surface vessels are in the neighbourhood. Other wise I was in charge of the longest schnorchel research mission ever at that time in our navy. 28 days submerged which I wouldn`t put in the category risky.
Tore

[SG]

Amazing, am speechless and grateful for your willingness to share your 1st rate experience with us. By the way what was the record depth KNM Kaura ever reached? did the crew experience health problems secondary to reaching sudden depth during the uncontrolled crash dive followed by subsequent fast surfacing? I Imagine you tested silent running as well. Was it effective? was it double checked by surface units hunting for the Kaura?

[OldNoob]

Wow

[tore]

SG
KNM Kaura had a pressurehull damage in main ballasttank no 3, dents possibly by depthchargers. These dents were repaired by some extra frames but we were not 100% sure she could take the max designed diving depth. We never took her deeper that 125 meters in my time. We did not have any noticeable healthproblems due to incident like sudden uncontrolled crashdives. The procedure after such event was immediately to repeat the same thing, but off course under full control.
Silent running was a must. We had annually a test at the RN noise test station in Loch Goil near Bute Island, the submarine was semisubmerged and underwater microphones were surrounding the hull picking up each  possible noise we made. This was  the only time I was fully in charge of the sub. The CO and NO 1 were ashore watching the instruments and the engineers and electricians were starting and stopping each motor and component being a potential noisemaker. Each component had the noise registered and in the end you got a certificate for each component to be used under silent running condition. We got the exact picture of the noise we were making and it was indeed effective.
Tore

[SG]

A good amount of great information! thank you so much Tore

[tore]

U 995 and present days execution.
Falo is finishing off his excellent photos of present days U 995 revealing the details of the externals. Apart from the previous comments I have a few remarks to modelbuilders.
As the German U 995 she  never operated as a schnorchel uboat. The schnorchel was installed March/April 1945. As a museumsboat she is equipped with a hinge float schnorchelmast, the original installed mast had a ringfloat. The schnorchel exhaust deck pipe and valve has been removed. The compass casing forward of conningtower was of the old streamlined type not the present days. For an Uboat serving in the Arctic I am not sure she has the right colour and the steel forecastle and poop deck is painted in a light blue-gray colour deviating very much from the dark wooden deck. A dark casingdeck all over was very important in view of the air-surveillance. As mentioned before , a wind deflector is fitted on the radarcasing, on the original U 995 it was not. The wind deflector on the rest of the tower was smooth rounded, not as today execution.
Tore

[tore]

Following up my remarks on the colour of the wooden deck I post below a page containing a translated page of the instructions to the Uboat Commanders from the German high command revised 1943.
Tore

[42rocker]

A little of topic, but
A friend of mine translates and sells the M.Dv No. 906 - Geheim!  Handbuch für U-Bootskommandanten which is the manual in the above post. If you are interested in a copy see

http://www.germanmanuals.com/REmanuals.html

John does a good job on all of his manuals.

Thanks to everyone for such a great thread.

Later Tim