Oil canning on german Subs??? Pics?

[Thunder]

Hi all, well i built a 1:72 scale revell u-boat, but after seeing Siara's build, i was ashamed and tore it apart again and am currently "oil canning" the hull

but...

Looking around I've seen the effect on US Subs but in no photo I've seen of uboats have i come across this "effect"

Does anybody out there have a picture of a Uboat showing this effect?

Tx for the help

Thor

[Thunder]

ok, spent a good few hours looking and I'm beginning to suspect the German subs did not have the oil canning effect?
http://upload.wikimedia.org/wikipedi...U_534_Hull.jpg

this is the closest i have found, but thats +60 underwater...

Anyone?

[Von Hilde]

due to the fact there was no pressure on the outer hull because of the limber holes would relieve pressure difference. Most dents and dings came from bumping into ships and other boats during operations. You usually see the oil can effect on aircraft with hi time airframes

[capatain avery]

I have a nice book on Uboats that have nice pics I will look it up..

[Osmium Steele]

I noticed no oil canning on U-505. While the welds were clearly visible, there was no noticable depression between them.

I was somewhat shocked as I thought it was common.

[Sailor Steve]

I would have thought so too, but Von Hilde's explanation certainly makes sense.

[Thunder]

Yeah. I looked through the entire thread regarding u-boat pics and didn't find one with the oil canning.
What i find curious is some of the guys modeling the revell uboat go into extreme detail, having done what i presume is a lot of research, and they model the oil canning effect.
http://models.rokket.biz/index.php?topic=443.315

I wonder where they got their pics from...

And another question would be , the basic flotation/diving principal between the US and German subs is the same, so why does the Gato seem to have such pronounced "canning?"

Got this from an online PDF on building the Revell model:

Oil canning - Boat hulls appear smooth from a distance, but up close, it is obvious that ribs or ***8220;frames***8221;
support the sheet metal skin. It is noticeable because the metal
is slightly indented between ribs. This is called ***8220;oil canning***8221;,
presumably because thin oil cans indent and deform when
squeezed.
This indentation happens naturally - there is much
more support at the frames. Other factors turn up the
intensity, like slight ripples to flat metal, unevenness,
differing expansion and contraction between the free metal
and the fixed metal, etc. Submarines add pressure from dives,
and depth charging. Though the free-flood hull casing would
not be affected by pressure (equal on both
sides), all the other factors combine to make
the ribs stand out even there.


However , as a reference photo, they used the Gato.
mmm, could making the oil canning on the Revell be wrong?

[Osmium Steele]

US boats show distinctive oil canning in their free flooding areas, U-boats don't seem to show much if any.

What was the typical thickness of the Gato/Balao class skins?

BROAD GENERALIZATION ALERT!!

We yanks tend to be thinner skinned than those across the pond. Perhaps our boats were as well?

EDIT: Gallery of U-505 pics during the original transit to Chicago. Note the obvious bumping/collision damage with a dearth of oil-canning.

However: U-995 in Lahoe shows a little bit of curvature in bright light, which is not visible in other pics in cloudier conditions.

[TLAM Strike]

Look at the center Type VIIA aft of the tower:


Far right boat, forward of the limber holes:

[Thunder]

Cheers Tlam.

Found one


Cool, so my hours of scraping have not been in vain...

[Von Hilde]

either rusting and staining the paint to appear darker or have just been re painted after corrosion control and appear lighter in the B&W pics, its hard to tell. If you check out close ups of the 505 and the 995 there is no oil canning and in fact, the outer hull rivets are mostly flush, small and somewhat indented. The Vesiko, appears that way as well. Thats due to the fact that when the boats came in for a short time between patrolls, the crew would hang over the side and hammer the rust off the rivets, and slop some red lead in the void and repaint just touching up around the rusty area. Not much time to spend painting the entire hull but alot of touch up on rusty worn spots. The tower and above deck were constantly being chipped and painted while underway. The, at sea corrosion control, on steel ships, was standard procedure to hammer the rust and old paint off, wire brush the area, then apply the red lead over the bare metal, before painting the color coat. This procedure was common among all Navy and merchant marine ships up until the advent of the air power hammers and grinders of today. You can see the different shades of grey paint areas in most close ups of the boats, where they have been chipped and painted,as well as some sections that were red leaded primer but not yet painted grey. I say,"Sand them rivets, on the Revell boats, those things are the size of goose eggs in 1/72 scale"

[Osmium Steele]

I tend to agree with you Von Hilde. Tin ripple is very minimal on uboats, and is usually only found on the sides of the deck structure near or just forward of the sail.

The 1/144 model I'm working on atm even has it straight from the mold.

You see no rivets on the U-505 and the welds, while visible, are not very prominent.