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Topic review - Calling all DKM U-boat Type VII fans
Author Message
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Vepr157 wrote:
I'm not sure where you're looking, but many sources mention the rod aerial (stabantenne). It was a slim (maybe 1-2" diameter; definitely not the same diameter as a periscope) antenna for radio communications while at periscope depth. The antenna provided with the Revell kit appears to be reasonably accurate. It appears that the aerial for the Type IX was in some cases a much thicker mast, which I assume is what you're referring to.

When you're asking a question, please post photos/drawings so that we know what you're talking about. It's hard to tell you what you're seeing in the photo of the U-203 if we cannot also see that photo.


1st of all, I did not ask a question. I presented a piece of information.

I know many source mention and illustrate the small rod antenna. And revell depicts the rod antenna as so mentioned and illustrated. The small antenna always seem to me to be quite disproportionate to the large bulge on the side of the mid-war VIIC conning tower that accommodates it. The bulge is actually larger than the bulge on the side of thr IXC conning tower that is definitely there to accommodates a periscope shaft sized extendable antenna mast.

So here is the photo of U203 with the periscope shaft sized antenna mast extending from the bulge:

Image


To assess its size you can compare it to the cylindrical portion of the attack periscope shaft visible above CO Mutzelburg’s left shoulder, behind the garlands.
Post Posted: Sat Aug 05, 2023 4:00 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
I'm not sure where you're looking, but many sources mention the rod aerial (stabantenne). It was a slim (maybe 1-2" diameter; definitely not the same diameter as a periscope) antenna for radio communications while at periscope depth. The antenna provided with the Revell kit appears to be reasonably accurate. It appears that the aerial for the Type IX was in some cases a much thicker mast, which I assume is what you're referring to.

When you're asking a question, please post photos/drawings so that we know what you're talking about. It's hard to tell you what you're seeing in the photo of the U-203 if we cannot also see that photo.
Post Posted: Sat Aug 05, 2023 3:33 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
it appears the prominent bulge on the port side of the conning tower that mid-war type VIIC usually have from around 1941 actually houses a massive extendable antenna mast whose shaft is the same diameter as the main shaft of one of the parascopes. It seems similar to the extendable antenna mast carried by early type IXC on the port side of their conning tower in the same position.

i found a clear photo of U-203 retuning to Lorient with this antenna mast extended.

yet i’ve found no references that mention this nor any drawings, including reproductions of original german plans, that show this on the VIIC, although many drawings of IXC shows this mast extended. revell missed it on their VIIC kit, giving only the option to extend a small jackstaff whip antenna out if this housing, although they too correctly showed the thick antenna mast option for their IXC kit.
Post Posted: Fri Aug 04, 2023 9:04 am
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Thank you. I already ordered it used through Amazon.
Post Posted: Wed Jun 28, 2023 7:53 am
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
I'd suggest getting a copy of Vom Original zum Modell: Uboottyp VIIC by Fritz Köhl and Axel Niestle.

Jacob
Post Posted: Mon Jun 26, 2023 12:17 am
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
The midship ballast saddle tank venting pipes on either side of the conning tower are almost as prominent as the diesel air trunk and pressure hull air circulation trunks under the casing, but every other reference for details under the casing seems to have missed them.
Post Posted: Thu Jun 22, 2023 9:33 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Thanks. The skitzenbuch is very informative. Far far better than the Anatomy of the Ship volume on the VII and highlight numerous serious omissions in the latter reference,
Post Posted: Thu Jun 15, 2023 5:06 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Ah thanks. That's an interesting book. Good drawings and photos, but somewhat questionable text.

I found this on p. 451 of the Skizzenbuch by Donald M. Prince:

Quote:
Direction Finding – A rotating loop aerial, approximately 2 ft. 6 in. internal diameter and about 2 ft. clear of the bridge casing when fully extended, was fitted on the starboard side of the bridge and could be raised, lowered and rotated from inside the U-Boat. The feeder cable was run from this aerial to the W/T Radio Room (cabin No. 1) and could be connected to the M/F and L/F D/F receiver (see (b) (5) previous page). This aerial and receiver could be used for obtaining D/F observations and alternatively for under-water reception on the L/F range (15-33 kcs)


Jacob
Post Posted: Tue Jun 13, 2023 9:04 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Unfortunately I don’t have the rest of the drawing. The image of the drawing is taken from this book: https://www.amazon.com/Hitlers-Attack-U-Boats-Kriegsmarines-Submarine-ebook/dp/B08N1HKNWV?ref_=ast_author_mpb
Post Posted: Tue Jun 13, 2023 6:17 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
That drawing probably shows the full range of motion of the mast. The inboard components appear just to be training gear to turn the antenna in azimuth. Where is this drawing from? It would help to know what the numbers correspond to.

Jacob
Post Posted: Tue Jun 13, 2023 1:53 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Image
Post Posted: Mon Jun 12, 2023 1:54 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Could you post the drawing you referenced? I am pretty sure the DF mast could not raise as high as the periscopes and there wasn't any hull penetration as far as I can tell.

Jacob
Post Posted: Mon Jun 12, 2023 1:34 am
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
VII and IX boats have a ring antenna for radio direction finding that retracts into a slot at the side of the open bridge when not in use. Photos of the ring antenna extended seems to be rare, and all the ones I’ve seen the ring rises onto a short distance above the edge of the open bridge. The same with illustrations in anatomy of the ship. However a photo of a original KM diagram of the ring antenna mechansim suggest the mast on which the ring is mounted is telescoping and there is a well inside the pressure hull for the mast, similar to periscope well that lets the long periscope shaft to retract. This would imply the antenna can be raised much higher than the rim of the open bridge, and can probably be raised as high as the attack telescope.

I like to confirm that before building a model with a ring antenna at attack periscope head level.

Has anyone seen any photos of a Uboat with ring antenna raised all the way up?
Post Posted: Sun Jun 11, 2023 10:26 am
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Thank you!
Post Posted: Tue Jun 06, 2023 9:19 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Ah "limber hole" means a hole in the free-flooding superstructure allowing it to flood and drain quickly. What you are referencing are "flood holes."

In the early 20th Century, nearly all submarines had flood valves (Kingstons) that sealed the bottom of the main ballast tanks. To dive a submarine would have to open both the vents at the top of the MBTs and the Kingstons at the bottom. During WWI the Germans realized that the Kingstons were unnecessary and omitted them, relying solely on the vents to keep water in the MBTs. Air could only leave the MBTs through the flood holes under exceptional circumstances, probably well over 45 degrees of roll and/or nearly 90 degrees in pitch, in which case the submarine was probably in dire straits for other reasons. The small amount of water remaining within the envelope of the MBTs was accounted for in the design. The vents were reliable enough to rely on them alone to hold air in the MBTs, a practice called "riding the vents." After WWI, the U.S. Navy eliminated most of the flood valves on its submarines and all current U.S. nuclear submarines have simple flood holes (albeit covered with gratings to reduce noise).

The Type II and VII had Kingstons for their amidships, internal MBT, probably for safety in the unlikely event that the vents failed. However, they were normally left open. The Type IX apparently had Kingstons on one of its amidships MBTs as well.

One additional thing to consider is that other types of tanks do require Kingstons. Fuel-ballast tanks, which can be used as MBTs after the fuel in them is used up, require Kingstons when acting as fuel tanks. Negative and safety tanks also require Kingstons. Kingstons also are occasionally used when flow-induced noise and vibration is problematic, although these days it is more common to use vortex-dissipating gratings.

Jacob
Post Posted: Sun Jun 04, 2023 6:45 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
On type II, VII, and IX, there are large numbers of limber holes under the external hull at locations corresponding to front and rear ballast tanks. Does this mean the ballast tanks were open to the sea on the bottom?

While this would make it easy fill the tank very quickly for quick diving and to blow the water out of the tank when the submarine needs to surface, it would only work right if the submarine is on a somewhat even keel. It also makes it impossible to completely empty the ballast tank because the bottom is v shaped and air will begin to escape out the limber holes before all the water on the bottom are blow out.

What do you think?
Post Posted: Sun Jun 04, 2023 6:17 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Apropos to this thread, a number of years ago I was given a 1/72 Type VII wood deck and resin accessories (hatches etc.). I will not be building a 1/72 scale Type VII, so if anyone is interested in the deck, it's yours for the asking. Only asking the person to cover postage costs. Leave me a post here or preferably a PM on this board.
Post Posted: Sat Jun 03, 2023 6:51 pm
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
Yes, the aft tube on the Type VIIB and VIIC had a shutter (verkleigdungsklappe) that faired the aft torpedo tube muzzle door. There is a drawing of the shutter and muzzle door assembly in Vom Original zum Modell: Uboottyp VII C by Fritz Köhl and Alex Niestle:

https://i.imgur.com/MyvatTZ.png

Here is a photo of a Type VIIB or VIIC showing the shutter:

https://i.imgur.com/wW5fo87.jpg

In regard to your question about the main ballast tank interior paint, the answer can be found in the 1940 regulations for submarine coatings:

http://www.u-boot-archiv.de/dieboote/farben_maerz_1940.html

Main ballast tanks were to be coated in several coats of bilge paint (Zellenfarbe, Bilgen) of an unspecified color, presumably whatever was at hand. I don't know what a typical bilge paint color was in the Kriegsmarine, but I think red or perhaps dark grey is most likely. I'd be curious if anyone has any insight into German WWII bilge paint colors.

Jacob
Post Posted: Fri Jun 02, 2023 3:28 am
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
The front torpedo tubes on VII boats have a round watertight inner door and a rectangular streamline outer flap. Do the rear torpedo tube also have some kind of outer flap covering the watertight round tube door? or the the round tube door exposed?
Post Posted: Thu Jun 01, 2023 11:04 am
  Post subject:  Re: Calling all DKM U-boat Type VII fans  Reply with quote
There are a number of limber holes on the bottom of type VII, through which keel beams, the body of torpedo tubes, and other underwater structures between outer hull and pressure hull etc are visible. What color would these be? Would they be painted the same anti-fouling gray as the outside of the underwater hull? Or would they be painted white?

A reason I suspect they might be painted white is on U-505 displayed in Chicago, some of the underwater interior structure between external hull and pressure hull, such as the bulkhead supporting the front ends of bow torpedo tubes, appears to be painted white.
Post Posted: Mon May 22, 2023 10:49 pm

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