Hull openings

[TopherVIIC]

Gentlemen:
Page 33 of the Type VII Manual lists the hull openings in the forwards torpedo compartment. In the druckkorper end cap, dead amidships, is a hull opening between the mine ejection valve openings. This opening is just above the LUT device, but is not connected to it. There is a three spoke control wheel for the valve. What is that valve? The other openings were discussed elsewhere on this forum, but I do not believe this opening was covered.
Christopher

[SnakeDoc]

Hi Christopher,


I believe, this wheel handle and opening is for the anchor chain slipper.


--
Regards
Maciek

[TopherVIIC]

Hi Christopher,
I believe, this wheel handle and opening is for the anchor chain slipper.
--
Regards
Maciek

Thanks Maciek.
Do you know if that is a mechanical device that links through to the anchor chain locker, or is it an air-line? I see the through/deck T-handle for the HP line for the ankerspill, (http://www.uboatarchive.net/U-570Plate11.htm) but it does not break the hull with an air line. Looking through the other plates, I do not see it indicated anywhere. It is not even on http://www.uboatarchive.net/U-570Plate25.htm where one would think it might be.
Always searching... Christopher

[SnakeDoc]

Hi Christopher,
I believe, this wheel handle and opening is for the anchor chain slipper.

Do you know if that is a mechanical device that links through to the anchor chain locker, or is it an air-line? I see the through/deck T-handle for the HP line for the ankerspill, (http://www.uboatarchive.net/U-570Plate11.htm) but it does not break the hull with an air line. Looking through the other plates, I do not see it indicated anywhere. It is not even on http://www.uboatarchive.net/U-570Plate25.htm where one would think it might be.

For sure it is a mechanical link - by shaft.
The control valve for the windlass and anchor capstan motor was inside the pressure hull, but only control shaft connecting valve with upper deck was going through the hull.


--
Regards
Maciek

[TopherVIIC]

Hi Christopher,
I believe, this wheel handle and opening is for the anchor chain slipper.
...
For sure it is a mechanical link - by shaft.
The control valve for the windlass and anchor capstan motor was inside the pressure hull, but only control shaft connecting valve with upper deck was going through the hull.


--
Regards
Maciek

Maciek,
Do you have any drawings or pics that you know of that show this chain stopper device or the mechanical link through the midship forward hull opening? I would picture it a long shaft going through the chain locker - probably at the base of where the chain goes through the "E" deck? I can envision a worm driven device that might clamp down on the chain... or was it a final safety cut-off, to cut loose the anchor chain from the ship? Just idle wondering, though it would be a detail I would like to add to my 3D drawing as well as my 1:35 work.
The opening looks smaller than the openings for the stuffing boxes for the muzzle-opening shafts - more like an air line opening to me. It is confusing! :-(
(forgot to add the pic...)
One idea (red) could use a 90 degree gear-transfer up to the device that looks like it might control the chain. I could be way wrong! The other idea (in orange) could use universal links to transfer rotation to a worm in the orange area I have boxed.
I also realize I could be way off the mark.




Christopher

[tore]

Christopher.
I believe your idea is not far from the real thing. The chainstopper is a very simple construction completely independent from the windlass, normally placed after the windlass but here obviously before. The windlass is placed off midship to port, but the wildcat and the chain midship thus it is a simple mechanical rodtransmission to the chainstopper.
My idea is similar to yours and the chainstopper is simply a bar screwed in between the chainlinks.
Tore

[SnakeDoc]

Hi,


when I have been writing about chain slipper (Anchor release mechanism, Ankerslippvorrichtung), I meant device, for releasing anchor chain (with anchor) - number 8 on below drawing:



I think, that shafts for chain stopper and capstan break/clutch were passing through the top of pressure hull.


Compare with similar arrangements on other boats:



--
Regards
Maciek

[tore]

Anchor winch.
May be it is an idea to describe a conventional anchor winch arrangement. The picture below shows a classic arrangement apart from me having put the chain stopper between the anchor winch and chainlocker as assumed for the VIICs.  There are two chain stopping devices and no 2 is the anchorwinch drum brake. Very often the procedure is to free wheel the wildcat and then release the chain stopper and let the anchor go by gravity.  On the VIICs, bitter experiences taught us otherwise. We released the chainstopper holding the anchor by the drumbrake and lowered the anchor carefully while going deadslow astern in order to prevent damage to the forward hydroplane being placed right underneath the anchor. In spite of that we had trouble once in Scapa Flow as the anchor chain stuck in between the hydroplane and the hydroplane gard preventing us to heave the anchor. It took us hours diving in long underpants in bitterly cold water ( wintertime)  before we managed to release the chain.

[TopherVIIC]

Maciek,
I found where you posted:

Zwalniak łańcucha kotwicznego to mechanizm, do kt

[tore]

Christopher.
Sorry I have no drawings of the arrangement. It is indeed possible and necessary to remote control the anchorwinch and anchorchain stopper from inside the pressurehull.  If in case of rough weather emergency you need to drop the anchor, the bow casing would be more or less inaccessible.
Tore

[TopherVIIC]

Tore
I quite enjoy hearing information like this:

On the VIICs, bitter experiences taught us otherwise. We released the chainstopper holding the anchor by the drumbrake and lowered the anchor carefully while going deadslow astern in order to prevent damage to the forward hydroplane being placed right underneath the anchor. In spite of that we had trouble once in Scapa Flow as the anchor chain stuck in between the hydroplane and the hydroplane gard preventing us to heave the anchor. It took us hours diving in long underpants in bitterly cold water ( wintertime)  before we managed to release the chain.

Information like that is rarely conveyed in books.

Now - I am off to romp in 3D virtual space and work more on my drawing. I have a long way to go.
Christopher

[SnakeDoc]

Hi  Christopher,

I like how you built that page, and that is exactly one of the scenarios I envisioned.

Thanks, the next compartment is prepared to be published.


Back to the anchor chain release gear - on this photo, I think is visible the shaft, which is extending toward the chain locker.



--
Regards
Maciek

[tore]

Maciek- Christopher.
I believe we are talking about two different things here. The chainstopper, which is operated from inside the submarine as described previously, and the fixing point at the bitter end of the anchorchain preventing the chain to disappear overboard. The latter is shown as the device 8 on Macieks sketch, 2 is the chainstopper.
On US submarines normally the end fixing point for the anchor chain is fixed at the upper part of the chainlocker in a tumblingblock which is operated from the casingdeck it cannot be release submerged. The end fixing point is not taking part in the normal anchoring procedure, but some times ( very seldom) has to be disconnected for overhaul. In the event of a very seldom emergency when it would be necessary to shed the anchor and chain, the tumblingblock would be released of course. In Macieks translation of the VIIC manual, you can read the text below, it is quite clear that the chainstopper (and anchorwinch) can be operated from inside, it is a bit unclear to me about the internal release rod of the thumbling block. So the question is if both the chainstopper and the endfixing tumblingblock can be operated by two mechanical devises inside the pressurehull, where is the second internal wheel? It would most common to have the end fixingpoint at the top of the chainlocker.
Tore

[tore]

Anchor slipping hook.
I guess evidence is found that indeed the anchor chain fixing device is operated from the inside of the pressure hull, the text below is from the the US naval inspection of a IXC but I believe this would be valid for the VIIC as well. See text below.
It is further confirmed that the chainstopper is of the screw-clamp type a picture of a similar device is shown below.
Tore

[tore]

Christopher.
To make a bit more confusion I checked the u historia last page of forward torpedoroom, on last page  they are showing their impression of the anchorwinch drive with the chain stopper control inside  on the top of the pressurehull together with another rod drive.  The chain fixing point is unconventionally in the bottom of the chainlocker with no internal shedding control. I would take this arrangement with a pinch of salt, but may be a look inside fwd top of the pressure hull would give a clue to a possible controlwheel of the chainstopper clamp.
Tore