Tores mailbox VIIC and VIIC/41 operation and technical details

[Katuna]

I have a question regarding the Aux cooling Water Pump location. I cannot seem to find any photos of the forward Stbd bulkhead area and I'm trying to figure out exactly where the pump is located. Is it completely under the deck plates? Looking at Simon's drawings it appears to be a vertical pump, slightly smaller than the Aux LO Pump.


I can't determine the elevation of the pump. I need to scratchbuild one which isn't that difficult. I just need to know where the heck it goes.

[tore]

Katuna.
no wonder, I don`t  have a photo of the pump but I guess you are able to see a small part of it under the writing plate, quite near the valve-chest on stb. side. I guess the pump has a bulkhead bracket to be fixed to the fore bulkhead, just beneath the floorplate. On my image you see the double sea inlet valve for the crossover pipe, might be an indication of the location. It is indeed a very narrow area and sharp pipebends.

Tore

[Don Prince]

A little better view....
Don_

[Katuna]

Thank you both so very much! I have anguished over that pump for ages. Well, maybe anguished is a little overly dramatic but nonetheless, it has puzzled me for some time. Thanks again gentlemen.

[tore]

Katuna I have taken one of Simons images of the coolingwater system, I am not sure he consider same final but superimposed my idea of the bulkhead mounted aux. coolingwaterpump
Tore

[tore]

About 10 years after the Norwegians decided to hand over KNM Kaura ex. U 995 they started the restauration of the tower from the Norwegian design to the orginal German design. Here is an image of the start of the tower restauration prior to the hand over ceremony november 1971.
Tore

[Katuna]

Tore - Thank you very much. That plate drawing is much easier to see too.


What were the main changes the Norwegian Navy made to the tower when they took possession after the war?

[tore]

Katuna.
As we didn`t need the heavy AA guns we dismantled the wintergarten as can be seen on my image below.
Tore

[tore]

Katuna.
A more modern version of the tower was the sail as shown on the image of knm Kya ex. U 926 below.
Tore

[Don Prince]

Hello Mr. Tore,

The photo of the modernized Kya reveals a clear wind screen at the front of the bridge/tower sail. Was it a fold down type or permanently in place. There also looks to be an extension tube to the aerial periscope. Did they switch from using the attack periscope while schnorchelling to the aerial periscope because of the larger head optics?

This would mean that they extender the length of the aerial periscope to place it near the schnorchel head... That would eliminate the issue with the exhaust gases in front of the attach periscope causing vision problems.

<See attached drawing>

Regards,
Don_

[tore]

Don.
The modernizing of our VIICs was an element of research in our plans for renewing/upgrading our submarine fleet. Although I was the chief engineer of KNM Kya ex. U 926 in 1954 I was not involved in this work, but knew the designer very well. I am sorry I don`t know the details. It was only modernized one of our VIICs, KNM Kya, as shown on the image. The conclusion of the research was it is better ( and less expensive) to build new submarines rather than converting the old VIICs hence we contracted 15 new  submarines ( a new class) in Germany. Time had passed and changed,  the situation was different and WW2 was remote and the VIICs were due for the museum.
Tore

[Don Prince]

Hello Mr. Tore,

U-926 became KNM Kya (S307) and served until 1962, and the submarine was scrapped in 1964. Using the reshaped bridge style of the Walther U-Boats, instead of the usual VII C bridge (Minus the wintergarden, the AA platform behind the bridge and the armaments), only an insignificant increase in speed resulted, but depth keeping properties were greatly improved. The final Kya bridge/tower conversion was very modest <attached photo> compared to the original proposed Walther bridge style renovation. The bridge sail had a notch on the port side where the un-modified schnorchel raised from the unchanged bed in the wooden deck structure.

Don's Note - Because of the increased height to the aerial periscope tube casing, it looks like they extended the length of the aerial periscope to just above the schnorchel mast head for better observation while scheorchelling. This accomplished two benefits: the aerial periscope had a larger optics head and tilted for better observation, and the placement of the attack periscope inback of the diesel exhaust vent created a vision problem at times.

It looks like the Norwegians put a lot of thought into the U-Boat Type VII C renovation project, and we have Mr. Tore to thank for preserving these photos from the past.

Regards,
Don_

[Don Prince]

Hello Mr. Tore and All,

Here are the attached photos of the only known printed version of Skizzenbuch. The metal covered leather post binder and the 11 x 17 inch 80 pound card stock paper and the printing cost came to about $690.00. This was my Christmas present to me!

Regards,
Don_

[Don Prince]

More images...

[tore]

Don.

Fantastic, some xmas present, but you deserve it, having the stamina to fulfil the collection of informations which makes the complete Skizzenbuch. It is of course an expensive task to print one of the kind book, but it must be a collectors item. Mission accomplished, congratulation!!
Tore