Author Topic: VIIC "On the Ways"  (Read 78021 times)

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TopherVIIC

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Re: VIIC "On the Ways"
« Reply #300 on: 13 Dec , 2012, 05:55 »
Here is one more shot of this valve


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Regards
Maciek

Outstanding Maciek! Thanks! That is exactly the pic I needed. I will fix the drawing today!
Christopher
« Last Edit: 13 Dec , 2012, 09:56 by TopherVIIC »

TopherVIIC

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Re: VIIC "On the Ways"
« Reply #301 on: 13 Dec , 2012, 10:18 »
More thoughts and observations on Torpedo Tubes:
Below are several pics showing the outer aspects of various ship's torpedo tubes. One is from Vesikko, there are Type IX and Type VII boats showing the same detail.
I am curious as to the fact that all of these boats seem to have somewhat thin castings that have the vent channel and two piston ear channels cast into the tube shape, yet the famous gray cut-away torpedo tube does not have these cast channels, nor do any of the tubes on U-995.


These should be visible if the actually exist on U-995, but I do not believe the bulges deform the exterior of the U-995 tubes. Clearly, though, the channels and vents are obvious inside the tubes. My question/theory is this: Are these tubes with the exterior bulges the earlier bronze tubes that were cast, and were the later steel tubes thicker, but having the channels cut into the tube with a smooth exterior?
As discussed in a previous thread, it was questionable as to if the exterior dimensions would be altered as that might make the fittings need adjusted. I submit that the thickness of the mounting pads would make up for changing to a thicker steel tube with thinner pads - thus keeping the mounting points the same.


U-164 The first one I plan on using extensively as this is the only pic I have seen that show the fixture mounting pads and bolt locations... but you will notice quite obviously the marked casting channels.

U-260 shows the same bulges near the muzzle and along the length


U-352 shows the obvious shape cast into the tubes.

Vesikko has similar bulges, and most definitely would have had earlier style tubes, although obviously not the same kind as on the VIICs and IXs.





Just thoughts as I was working this morning...
Christopher


Offline NZSnowman

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Re: VIIC "On the Ways"
« Reply #302 on: 13 Dec , 2012, 10:48 »
Christopher, I believe we can verify this easily by looking at the tubes of the Type XXI and XXIII as there tubes I am sure are steel. We just need a few good photo

TopherVIIC

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Re: VIIC "On the Ways"
« Reply #303 on: 13 Dec , 2012, 10:50 »
Christopher, I believe we can verify this easily by looking at the tubes of the Type XXI and XXIII as there tubes I am sure are steel. We just need a few good photo

Offline SnakeDoc

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Re: VIIC "On the Ways"
« Reply #304 on: 13 Dec , 2012, 11:00 »
Hi Christopher


Great work with these "external bulges". I would never think, it could be done that way.


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Maciek

Offline SnakeDoc

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Re: VIIC "On the Ways"
« Reply #305 on: 13 Dec , 2012, 11:22 »
Christopher, I believe we can verify this easily by looking at the tubes of the Type XXI and XXIII as there tubes I am sure are steel. We just need a few good photo

Offline NZSnowman

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Re: VIIC "On the Ways"
« Reply #306 on: 13 Dec , 2012, 11:31 »
Christopher, I believe we can verify this easily by looking at the tubes of the Type XXI and XXIII as there tubes I am sure are steel. We just need a few good photo

Offline SnakeDoc

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Re: VIIC "On the Ways"
« Reply #307 on: 14 Dec , 2012, 01:40 »
Maciek, I did not realise they werepiston-less. Why did they remove the piston system?


The following disadvantages of the piston caused it to be abandoned:
1. there was some leakage of air bubbles, especially on the return stroke when the inertia of the piston and incoming water column caused peaks of pressure behind the piston which momentarily exceeded the outside water pressure.
2. As a result of the close clearances required between the piston and the tube, any slight deformation of the tube was sufficient to put it out of commission. This problem was so serious during the war (because of depth charge damage) that some U-Boats required one or more tubes to be replaced after each patrol. The influence is shown in the Type XXVI design, where the torpedo loading hatch was made large enough to permit the passage of the after (internal) section of the tube, thus enabling replacement to be made in some cases without docking.
(see also: http://www.uboatarchive.net/BDUOrder61.htm)
3. The piston had to be removed for each reload.
4. The construction of the tube barrel was heavy and complicated by the guide slots and buffing chambers. Moreover, the weight of a piston for each tube was added.
5. Extremely accurate machine wokr was required on both the piston and the tube.
 

The absence of the piston simplified the construction of the barrel, there was no difference between the surface and submerged launch. Moreover, the new design allowed launching torpedoes from depth up to 100 m.


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Maciek

Offline SnakeDoc

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Re: VIIC "On the Ways"
« Reply #308 on: 14 Dec , 2012, 01:55 »
I have attached two photos of aft torpedo tubes from U995 with visible external bulges. I don't know, if these tubes are made from bronze or steel - on the attached photo of tube interior it seems for bronze, but I do not have knowledge and experience to say on the basis of photo.


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Maciek

TopherVIIC

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Re: VIIC "On the Ways"
« Reply #309 on: 14 Dec , 2012, 06:01 »
Thanks Maciek -
I suppose that defeats rather soundly my theory that late period tubes did not have the bulges - I just needed the right photo, and your two definitely show them. None of the ones I have had until now show a definitive bulge.
Good to know.
It does tell us one thing for sure - putting a string or a tape measure around them to get an external diameter will not be exact with the bulges in the way, but could still be reasonably close. We still need someone to find wall thickness with calipers. If only we new someone at Laboe!
I will continue to plod on...
Christopher

TopherVIIC

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Re: VIIC "On the Ways"
« Reply #310 on: 16 Dec , 2012, 18:58 »
Thanks Maciek -
I suppose that defeats rather soundly my theory that late period tubes did not have the bulges - I just needed the right photo, and your two definitely show them. None of the ones I have had until now show a definitive bulge.
Good to know.
It does tell us one thing for sure - putting a string or a tape measure around them to get an external diameter will not be exact with the bulges in the way, but could still be reasonably close. We still need someone to find wall thickness with calipers. If only we new someone at Laboe!
I will continue to plod on...
Christopher

Perhaps it does not destroy my theory...
On excitedly examining these aft torpedo tube images I have not seen, I notice that the U-995 aft tube seems to have the bulges for the vent and piston ear keyways - just like the Tube II from U-164 but I notice it DOES NOT have the double row of hex bolts that should be visible between the mine release lever and the upper (in this case it would be the extreme aft) mine release airline ...just like the Tube II from U-164.


Vesikko has the bulges - but not the double row of bolts running longitudinally...


The disputed "Wavy Navy/German Training pic tubes have the double row of bolts, indicating a possible lining...


The pic of the forward exterior of the tubes projecting through the bow cap show the double row of bolts traveling the length of the tube, AND what looks like a minor piston keyway bulge... but it is not as deep as the bulges visible on U-260 or U-352


I suspect the double row of bolts holds the liners in on the forward tubes, but still think that the aft tube may be older on U-995 and was not replaced. Could it be that U-995 has a bronze tube for the aft tube, and steel tubes forward?


It is not hard for me to imagine that during wartime, it might be prudent to replace or update a ship's main armament in dry-dock, but not to worry about the aft tube... or if wartime supply was interrupted, to update only the forward tubes. U-995 was laid down late in the year in 1942. Do we know if she started with all bronze tubes and had some replaced, or did she start with a mixed lot?

(not all of the images referenced did I re-link pics to save bandwidth but you can see them in the orig. post)
Christopher
« Last Edit: 16 Dec , 2012, 19:27 by TopherVIIC »

TopherVIIC

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Re: VIIC "On the Ways"
« Reply #311 on: 24 Dec , 2012, 16:05 »
Happy Yule, Merry Christmas, Gledelig Jul, Happy Festivus, Wesolych Swiat Bozego Narodzenia and Fr
« Last Edit: 24 Dec , 2012, 16:10 by TopherVIIC »

TopherVIIC

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Re: VIIC "On the Ways"
« Reply #312 on: 30 Dec , 2012, 21:30 »
I hope all have a happy and prosperous new year.
Here is a cool picture... You may or may not have seen this but I think it is very nice...
Take the time to look through the whole photo stream...
2-cm MG C/30 in Unterseebootslafette
8,8 cm Schnellade Kanone C/35
« Last Edit: 30 Dec , 2012, 21:42 by TopherVIIC »

Offline SG

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Re: VIIC "On the Ways"
« Reply #313 on: 31 Dec , 2012, 08:07 »
Amazing stuff, Thx Christopher!!!
 ..and a Very Happy New Year to you too!!
« Last Edit: 31 Dec , 2012, 08:09 by SG »

Offline Rokket

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Re: VIIC "On the Ways"
« Reply #314 on: 31 Dec , 2012, 18:55 »
Wow 60 years dry! Nice seal work!
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