Aft torpedo tube type VIIc

[Grimsby]

Hello. I need help with the outer cover aft torpedo tube of a type VIIC. How do you open the lid?
I have not found any pictures in the open position.

Sorry. My English is not very good.

Greetings.

[Jan]

Hello, had the same problem...according to a drawing, in "Vom Original zum Modell", there are actually two lids: One "inner lid", which closes the torp-tube and one "outer lid" which kind of "hides" the whole story. Unless you want to display your boat with an open aft top tube, i think you can take a pic of U-995s aft torp tube as a guide...

[Grimsby]

Thanks Jan.

I really want to leave open those two caps for display within a torpedo.

[Rokket]

This is for U 505, a IXC, but it is the same thing, just two tubes not one. The actual hull door ("shutter") is a little different, that opened UP on the VIICs. I'll see if I can find a shot of that too...but this is the tube part with tube door;



Very Outside ("hull) door = SHUTTER (on USNavy subs)
Muzzle door = OUTER DOOR
Breech door = INNER DOOR

[Grimsby]

Thanks Rokket.

Very good picture.

I also still looking for some of VIIC.

Regards.

[Pat]

Interesting that the colour inside the casing is a lighter grey than the outside antifouling paint.  That means that it would be easier to see the inside details on the pressure hull of model since you can make the colour lighter.

[Jan]

Hmmm, I doubt those colours are authentic... but who knows...

[Rokket]

Yeah, the colours are  abit bluey - in real life, not just the pic. I would be guided by Dougie's research.

[Rokket]

Here's U 995. She's hacked up and modified and unauthentic, but the stern seems OK. Not my pic so have tried to brighten a bit.

[Pat]

I agree that the outer antifouling looks way too blue.  Either an artifact of the photography or somebody has it wrong.  The antifouling colours I see are normally anywhere from a medium grey, through slate grey to black.

I was thinking more about the interior colours just being lighter than the exterior rather than an exact copy of the colours in the photo.  Is it possible they used the topsides colour on the interior parts that were not constantly submerged? 

Antifouling paint is about 3 X more expensive than topsides paint and it uses up copper (all modern antifouling paints and many WWII paints) or tin (banned these days but common in WWII era) which might have been in short supply for other purposes during the war.  It's also a lot more difficult to apply since the fumes can be dangerous even when painting outside.  After all, antifouling paint is meant to kill marine life.  Anybody who's ever put on antifouling can recognize its very distinctive smell.

Antifouling would also increase galvanic action (the reason for the zincs on the rudders and dive plane supports that I talked about before) and it has to be reapplied frequently, at least once a year or more in tropical waters, as opposed to the topsides paint that can stay there for the life of the boat (until it rusts off anyway) and doesn't cause any problems with the metals.

So I'm wondering if for those reasons, they might have used as little antifouling as possible and used the topsides paint for any surfaces, including those inside the casing, that weren't underwater all the time.

[Seewolf]

Hello Pat,
the anti fouling paint is all the time giving poison to the water around the boat to kill marine live, that means the boat is swimming in a cloud of death for small marine life, it is no need to paint the inside with antifouling will be to much work to expensive and to much time consumption... and will not increase the antifouling effect because it is allready a poison cloud around the boat.
But the question wich paint, light or dark gray... that you have to find out for every single boat... I know for Blohm & Voss U 96 was in the early time a light gray so I guess will be the same for my U 98.
But dark Grey is also possible for other boats, in the early time more common to use light grey but not an 100% must.... very difficult, to much dockyards to less pics 

[Pat]

Seewolf, I understand the colours of the outer hull of the boats.  What I'm talking about though is the inside part, between the pressure hull and the casing.  It's not underwater any more than the outside part of the topsides, so the question is whether it would have been painted with antifouling, like thelower pressure hull, or regular paint, like the topsides and conning tower.

The outer part of the boat I'm building U-711, appeared in photos to be a very light grey (or perhaps even white, which was seen on some Arctic route boats - it's hard to tell), with three black swirls, one about midway from the bow, one midway to the stern and one by the conning tower.

The problem is making the inner parts visible since it's very dark looking through the free flood holes in the casing.  If they're dark antifouling, they're very hard to see but if they're the same colour as the topsides then they might be easier to see.  And since topside paint lasts longer and is cheaper to make etc. as I said, then it seems reasonable to think they might be painted topsides colours.

[Seewolf]

Hi Pat,
The inside parts between the pressure hull and the casing, I don`t belive that this parts are painted with antifouling because of reasons I wrote above. But of course that don`t answer your question... realy I don`t know, in the moment I`am more concentrated on the VII C`s but the most pictures of the later VII c/41 looks dark between the casing    I guees, like you,  it is ordernary primer or paint.

[Pat]

Seewolf, that DOES answer the question to an extent.

If the parts between the casing and the PH were primed and painted with topsides paint and not antifouling, then they could in effect be almost any colour.  That means that they could be dark on some boats, or light on others depending on what was available in the shipyard at the time.  Or what colour the parts came from the various suppliers.

For instance, hi-pressure air lines or tanks might not necessarily be the same colour as the spare torpedo storage tanks, and neither might be the same colour as the air intake ducting or exhaust pipes.

In particular, it might be reasonable to think that some of the shut-off taps and valves would be bright red to be able to see them in an emergency or while working during refit.   Underneath the deck the bright red wouldn't matter, since any enemy close enough to spot the colour between the decking would already have seen the boat.

I've often wondered about the colour of the hi-pressure air tanks in that regards since at least today, welders oxygen tanks are a royal blue while the acetylene tanks are sort of a moss green.  (Or perhaps I have them reversed, I don't weld)  In any case, it makes sense to be able to tell them apart easier.

Again, if that's the case, then it means that we could make these in-between parts more visible through the free-flow holes by using different colours.  This would make them show up a little better in the dark. 

Not that the colours would be vastly different.  But if even some of the parts on top of the PH were the colour of the topsides (different shades of grey) and the air lines and tanks say a welding air blue, it would give them some definition in the dark.

Now, if only there was some way to find out for sure.

[Seewolf]

Pat this is the warnavy order for painting U-Boote, order No 31 March 1940

PH and coning tower inside:
two times primer- color not specified
under floor - white
opper floor - ivory
bilge - color not specified
and so on and so on

PH and conning tower outside:
under waterline
                      - two times primer - color not specified (common was 1.primer darck orange/red/brown 2. primer light gray, but maybe varies from dock to dock)
                       - one time waterline paint I 21a - grey

PH                    - one time waterline paint III 23b - grey, one time waterline paint I 21a - grey
-------------------------------------------------------------------------------------------------------
over waterline
                     - two times primer - color not specified, two times camo paint petrol resitent Tp58 - grey matt OR two times Ka 51 - grey matt

Amendment to this order is: the exact paint for every Boot is to ask by HQ comand (B.d.U.)

During the war the dockyards and docks at the U-Boote bases have had  to use what they have, means a lot of improvisation.
This source about the painting I found in the net, somewhere... don`t know how thrustfull it is. 1944 they changed the order a little bit but mostley depends quality of paint and primer.
Cheers
   

[NZSnowman]

Pat, I believe the high pressure air lines were non-painted as they were bronze, reinforced spiral woven piping. Below is a great picture of them laying out the high pressure air lines.

[Seewolf]

Hello Simon,
firts at all very good Pic. never saw it, is it from a book and if,  are there more of this interesting Pic`s ?
I guess these are VIIc/41 boats (because of the Wintergarten and galvanized steel) the silver parts (pipes and Conning tower) should be galvanized steel, there was a special order how to paint galvanized pipes, if I remember correct it was a bronze primer or paint but I`am not quit sure and I think the outside pipes get over the bronze one time grey paint. Maybe some body here know it more exactly. My big question is, the early VIIc boats had no galvanized steel... but later it came common to use galvanized steel (it is good to see on the different weathering of early VIIc and later VIIc/41 conning towers). Did anybody know what time or wich U-boat Nr.  they start to use galvanized plates for the tower ? and, where I`am allready so far off topic, what time they changed from bronze propeller to steel propeller?

[Pat]

Seewolf, you post of Sept 29 again makes it sound like the PH is treated one way for paint, and anything above the waterline (and therefore the parts inside the casing?) might be a different colour ("..two times camo paint petrol resitent Tp58 - grey matt OR two times Ka 51 - grey matt")

It isn't conclusive yet, but it sounds like the parts we'd see insde the casing through the free flow holes could be the lighter colour of the topsides, and therefore a little bit easier to see in the darkness.

I'm pretty sure you're correct too that the colour and treatment would differ from one yard to another, depending on what's available and what the particular project manager thought was appropriate.

[Pat]

Simon, that's exactly the sort of information I was looking for.  If the hi-press air lines were non-painted bronze then they would stand out against the dark grey antifouling colour of the PH.  Bronze makes sense also as it's non-corroding and non-fouling by virtue of the alloy anyway, so it wouldn't need painting.

All the original fuel lines in my own boat were bronze, until I replaced them a few years ago with diesel-resistant hose, so it seems that it was a commonly used material for such work in times past.

Wonderful picture.  And I'm glad you posted it while I still have my deck framing open.  I see a couple more beams that I wasn't aware of, such as the aft "V" going to the rear of the deck gun plate making afull diamond instead of just the forward pointing "V" that I have.

[Seewolf]

Pat this is the painting order March 1940
Deck equipment
none galvanized parts two times primer two times camo paint Tp. 58 or Ka.51 - gray matt
galanized parts two times primer - color not specified, two times camo paint petrol resitent Tp58 - grey matt OR two times Ka 51 - grey matt
Light metal (like Alu ) 2 times RAL 9002 2 times RAL 7000 or 7001 - light grey or darl grey

painting order Juli 1944
Deck equipment
none galvanized parts two times primer two times deck paint Nr. 58 - mod grey
galvanized part two times deck paint Nr. 58 - mod grey

source is from: Deutsche U-Boote Geheim 1935 - 1945
Autor: Richard Lakowski
but he said in painting order from 1944 the antifouling paint should be red......... so I don`t know what to think about, I only know I will not paint my boats with a red under water hull 
It looks like there is no easy way to say that is right and that is wrong....... unfortunately. If I check my pics I can see both light and dark grey, must say mostly a light greay appears on the big boats like the IX boats but the reason for that could be the bigger floodholes. General it looks for me, in the moment, so earlyer the boot big possibility for light grey, so later it is more a darker grey. Also possible when paint worn away that the light grey primer appears back... of course pure gueesing. 

[NZSnowman]

The picture is from U 995: Das Boot von Laboe. Der Typ VIIC - Entwicklung und Technik. Der U-Boot-Krieg 1939-1945. by Eckard Wetzel but it

[Pat]

Simon, I can understand what you mean about the shock finding out that the hi-press lines might be flexible hose wrapped with spiralled metal rather than tubing.  I've wondered a few times in similar applications (not submarines) where I've seen flexible instead of tube.

Of course, flexible IS much easier and faster to install, as I found out when I changed the fuel lines on my boat.  No joinery at bends and it only took minutes, rather than hours, to feed it through all the bulkheads and openings from one place to another.  I might have needed expert help to install tubing but flexible I could do all the work myself. 

As for the boats in the pic, They do look like VIIC's, not VIIC/41's, mainly because of the 88mm bases and the ready ammunition cannisters for same.

However, I'd think the basic substructure of ribs, bulkheads and deck frames would be the same for either version.  It wouldn't be complete redesign for that aspect.  The lower wintergarden is a structure built up on top of the deck so wouldn't necessarily have a lot of different structure underneath it.  In fact, since some boats had the lower platform added on after a few patrols (U-711 that I'm building is one such boat), it's likely that no substructure was needed.

A question though.  In the centre boat in the picture, there seems to be a flat base that the felxible lines are going in to.  Any ideas what that is?  I don't see where it matches any structure on top of the finished boat.

[Rokket]

The red is controversial and Dougie covers it in his Paint info document.

I just fond that a LOT of internal and external piping on Gatos was bronze, but you never know because it's painted. I would think the bronze would be painted if at all visible...nothing like a shiny pipe poking through some slats or holes to give away a sub. (It would seem easier to just spray the whole top of the p-hull and under casing, faster)

[Pat]

Wink,

The bronze wouldn't stay shiny for very long.  It quickly takes on a dullness and then a patina like a statue, especially in salt water. 

So painting wouldn't be faster than just letting the bronze oxidize, which wouldn't take more than a few weeks, less time than it would take to finish construction.

Plus, since it can only be seen through the floodholes or between the deck planks, and not only does the light have to shine on it but reflect back through it exactly in line with the observer, I doubt there'd be much chance of it giving away the sub.  If one were close enough to see such and odd glint in among all the glinting off the waves themselves, then I think the sub would already be spotted.

My guess is that inside the casing could be bright yellow, and still almost invisible to an observer from a few hundred feet away, let alone an aircraft spotter at 5.000 feet altitude.

[NZSnowman]

As for the boats in the pic, They do look like VIIC's, not VIIC/41's, mainly because of the 88mm bases and the ready ammunition cannisters for same.

However, I'd think the basic substructure of ribs, bulkheads and deck frames would be the same for either version.  It wouldn't be complete redesign for that aspect.  The lower wintergarden is a structure built up on top of the deck so wouldn't necessarily have a lot of different structure underneath it.  In fact, since some boats had the lower platform added on after a few patrols (U-711 that I'm building is one such boat), it's likely that no substructure was needed.

I have always wondered about this. Did they remove the base support for the 88mm from the Type VIIC/41

[Pat]

Simon, I've seen cutaway pictures of late war U-boats, some with the deck gun base hidden under the deck, and some without.

I suspect that it's as you said, that if the base was already there, they just removed the gun and left the supports in place for just the reasons you give.  Also, removing the base could weaken the structure somehow at the support bracket positions.

If it was a newer boat being built after deck guns were removed, they didn't bother putting in the base.

Dinner is ready, I'll answer the other part later.

[Pat]

Well, it might be a floor for the extended wintegarden, but if these are earlier boats with the deck guns, as it looks like, then did they have the lower stages for the wintergardens then?

Also, if the rest of the deck was wood, even including the deck at the top of the conning tower, why would they make it metal for the inside of the wintergarden where hardly anybody would ever go?  It would only impede water flow and make diving slower. 

I'm pretty sure that when the wintergardens were extended in older boats, they wouldn't have taken up the wooden deck and replaced it with metal.

If it is the deck for the extended wintergarden, then it proves for sure that the outer decks were wood for traction, and not for saving metal as I've seen some people opine.

[Rokket]

traction was critical as Pat goes into detail about. The Gatos that reduced the wood part of the decks at least used perforated metal, for drain/flooding and I guess traction...

[Rokket]

Oops, forgot - Pat, yes, based on my VIIC model and P-hull/casing, I think you're right about the bright yellow!