Aft torpedo tube type VIIc

[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!