Author Topic: Two marks on the hull of Type VII (Read 10513 times)

JAORSA · « **on:** 09 Aug , 2009, 11:03 »

Hello everybody!

A technical question;
could somebody say me that they are those two marks on the hull of Type VII?
so that they serve?
what function has?

Thanks

conus00 · « **Reply #1 on:** 09 Aug , 2009, 13:21 »

Siara would be the one to ask. He studied VIIC extensively.

billp51d · « **Reply #2 on:** 09 Aug , 2009, 13:31 »

I think you'll find that they're a mystery to everyone in the modeling community. Good luck..
Cheers/Regards, Bill

Siara · « **Reply #3 on:** 10 Aug , 2009, 00:50 »

Bill is right- none knows what the 2 bumps are for. One think is certain- you need to sand them down, and replicate them in slightly different place ( higher ). Study the pictures to locate where the bumps should be, as Revell didnt do the homework properly.

Rokket · « **Reply #4 on:** 12 Aug , 2009, 05:47 »

Even The Masters know not what they are...much speculation, but no answers.

This is when we need time machines. Sure, they would be useful for much, but some stuff they would just make easy. here they would be the only answer.
They are positioned slightly wrong in the Revel kit as Siara says.

Bad Karma · « **Reply #5 on:** 15 Aug , 2009, 04:15 »

I have asked this question on a Dutch forum.

This is a answer from Jeff la Rue,

__________________________________________________________________________________________
If memory serves.....those are the (compressed air) vents for the torpedo launch system.
There should be four of them (two on each side)...
one for each forward torpedo tube.
----------------
Jeffrey W. LaRue
___________________________________________________________________________________________

Here is a pic of the decompression tanks.

billp51d · « **Reply #6 on:** 15 Aug , 2009, 05:56 »

   Originally I thought the same that they were to exhaust the spent gases from fireing torpedoes but I was later told that that these gases were recaptured so that bubbles would not give away the u-boat location.
   Doing an overlay of the pressure hull and the 4 cylinders even suggest that these "bumps" are somehow connected, however I was told not.
   After scratching my head and pondering "what else could they be?" i've finally concluded that.....
   1. They're for side view mirrrors ?

2. Perhaps .... turn signals ?

3. Relief tubes for the crew ?

And so the mystery continues.....
Cheers/Regards ...Bill

Rokket · « **Reply #7 on:** 15 Aug , 2009, 19:25 »

Yes, i USN boats the air and water were sucked back into a Water Tank Round...venting would be a DEAD give-away. I think bill's right, turn signals!

Pat · « **Reply #8 on:** 02 Feb , 2010, 16:49 »

How about some sort of pressure relif valve? Like when trucks with airbrakes 'fart' every once in whileto let off excess pressure since they have to keep constantly pumping air into them to stay within a certain range.

If that was the case, they wouldn't let off much air at any given use, so not much chance of being spotted.

NZSnowman · « **Reply #9 on:** 02 Feb , 2010, 18:28 »

I to also thought about the compressed air vents for the torpedo but I have look at the Torpedo tube firing, venting, flooding and drainage systems schematics from U-570 and can not found any outlet through the pressure hull. The other thing I ask myself if it is a compressed air vents where is the vent for the stern torpedo?

Below is a list of opening in the pressure hull in the bow section that were are four of. My feeling it must be the eight openings for the Flooding torpedo tubes and Draining for torpedo tubes $:-\$

4x Torpedo tube outer doors
4x Passive sonar array
4x Transmitter for underwater telephone
4x Mine ejection
4x Flooding torpedo tubes
4x Draining for torpedo tubes
4x Torpedo nozzle forward

http://www.uboatarchive.net/U-570Plate25.htm

Pat · « **Reply #10 on:** 02 Feb , 2010, 20:50 »

I agree, those look like reasonable suspects as to their use. But the same question applies: where are they for the stern tube?

Rokket · « **Reply #11 on:** 02 Feb , 2010, 23:29 »

Actually, it probably isn't for torps - to prevent airbubbles from escaping (tell-tales), the water and air were sucked back inside the sub. In Gatos it could go to a tank for this purpose, or sent to ballast tanks. (also vented outside, but that would be less common, as in, only do-able when not going to be seen).

NZSnowman · « **Reply #12 on:** 24 Feb , 2010, 19:48 »

I am currectly reading Iron Coffins by Herbert A Werner

Here what he writes on page 38

"The compressed air, which had activated the large pinlock that expelled the torpedoes, was released into the boat instead of the water, thus avoiding the bubbly swell on the surface that had revealed the position of submerged U-boat during World War I."

SnakeDoc · « **Reply #13 on:** 25 Feb , 2010, 05:55 »

Quote from: NZSnowman on 24 Feb , 2010, 19:48

"The compressed air, which had activated the large pinlock that expelled the torpedoes, was released into the boat instead of the water, thus avoiding the bubbly swell on the surface that had revealed the position of submerged U-boat during World War I."

http://uboatarchive.net/KTBNotesArmament.htm

Don in Cincinnati · « **Reply #14 on:** 25 Feb , 2010, 09:24 »

Quote from: NZSnowman on 24 Feb , 2010, 19:48

I am currectly reading Iron Coffins by Herbert A Werner

Here what he writes on page 38

"The compressed air, which had activated the large pinlock that expelled the torpedoes, was released into the boat instead of the water, thus avoiding the bubbly swell on the surface that had revealed the position of submerged U-boat during World War I."

I am at as much of a loss as to the function of the two "bumps" as everyone else, but here is another piece that may help to eventually solve the puzzle. On page 36 of Showell's book U-Boats in Camera the top picture on the page shows a type VII in drydock and the two bumps can be seen from a 3/4 rear angle. They are clearly some sort of tube and not just a solid mass.

Mr. Bill · « **Reply #15 on:** 11 Mar , 2010, 20:45 »

Hello Jaorsa,

I am very interested in the second photo you posted at the beginning of this thread. It appears to be a very early pre-war VIIB boat (bronze eagle and shape of the conning tower).

Do you have any details about this photo such as which boat or the date it was taken? Do you have a larger image? I am especially interested in the lower flooding vent pattern at the bow.

Thank you!

Bill

JAORSA · « **Reply #16 on:** 12 Mar , 2010, 15:54 »

Hi Bill!

This picture sent me Dougie. I think he has a better quality picture. It is the U53, I believe that is the day of its launched (06-05-39 in the shipyards of F. Germaniawerft).

There is another photo of the U54 (15-08-39) where you can see more clearly the pattern of holes of flooding of the earliest type VIIB.

To my U47 of Amati, I used the pattern VIIB "U-Brass "(Dougie and Wink). It gives a good result.

Cheers!

Javier

Rokket · « **Reply #17 on:** 12 Mar , 2010, 16:48 »

nice work Jaorsa!

dougie47 · « **Reply #18 on:** 14 Mar , 2010, 09:37 »

Hi Javier,

It really is great to see the U-Brass VIIB cheek used on an Amati U 47. Thanks for posting, you've made my day!

Cheers,

Dougie

Mr. Bill · « **Reply #19 on:** 15 Mar , 2010, 05:56 »

Hello Javier,

Very nice work on the Amati U-47! This is a very ambitious project. Thanks for posting the additional photos, I am also interested in the flood vents under the forward dive plane - these are almost never seen in photos of VIIB's. I also noticed a third "bump" in the photo of U-54 located near the extreme bow edge just below the lower torpedo tube door. Does anyone know what this is? It looks similar to the two "bumps" located further aft.

Bill

NZSnowman · « **Reply #20 on:** 15 Mar , 2010, 21:15 »

Quote from: Mr. Bill on 15 Mar , 2010, 05:56

Hello Javier,

Very nice work on the Amati U-47! This is a very ambitious project. Thanks for posting the additional photos, I am also interested in the flood vents under the forward dive plane - these are almost never seen in photos of VIIB's. I also noticed a third "bump" in the photo of U-54 located near the extreme bow edge just below the lower torpedo tube door. Does anyone know what this is? It looks similar to the two "bumps" located further aft.

Bill

Bill, it is the Pitot Tube for the speedometer for the Underwater Log System. Check out the discussion we had about it between Reply #348 & Reply #369 http://models.rokket.biz/index.php?topic=106.msg4505#msg4505

Pat · « **Reply #21 on:** 15 Mar , 2010, 22:54 »

Yes, that would have been my take on that bump also. Especially since the opening is facing forward, not aft.

And that seems to be a lot better location for it since it's to the side, not right on the cutwater, and low enough down that it would be in the water under most conditions and wouldn't be hit by floating debris.

Another question comes up from that pic though.

Up just behind the cutwater at about the waterline, there's one opening in the hull. I'd thought from Dougie's article, that the port side usually had 3 holes there, (as in the Revell kit) and the starboaurd side had 2. In this pic, there seems to be only 1 hole on the port side.

Anybody any ideas why?

And what are those holes for anyway? They don't seem to be located anywhere that it would help a dive or access any equipment. And it seems odd to have a different number on each side. They just don't seem to fit in with the other holes along the casing, which make much more sense.

NZSnowman · « **Reply #22 on:** 15 Mar , 2010, 23:17 »

Pat, you are right, 3 on the starboard and 2 on the Port. Not sure why only one $:-\$ Maybe the dockworker were is a hurry to get home that day

.

I checked my drawing and plans and you are right! Nothing is in that area of the bow. The only real thing in this area is 'Stringer II'. The holes must be used to drain the water from the bow but you would think it would be lower near to 'E' deck $:-\$

Siara · « **Reply #23 on:** 16 Mar , 2010, 01:42 »

Maybe that the holes are for draining the chamber where the tow hook is located?

NZSnowman · « **Reply #24 on:** 16 Mar , 2010, 02:40 »

I also initial thought they were to help with the draining of the tow hook well, but these hole are approximately 1,050mm below and 500mm forward of the tow hook well $:-\$

Mr. Bill · « **Reply #25 on:** 16 Mar , 2010, 07:58 »

I believe the single vent hole that Pat mentioned in the photo is standard for the early VIIB boats, maybe all B's. I could be wrong, but I think there is a single flood vent hole on each side. At least that is what I have seen in photos. The pattern of vents in the area changed with the VIIC's. I think this is all described by Dougie in his article, maybe he can confirm for us.

Cheers,

Bill

Mr. Bill · « **Reply #26 on:** 16 Mar , 2010, 13:12 »

Hello Simon,

Thanks for the message references regarding the pitot tube. It does seem that this was not a standard configuration for VIIB boats, at least I don't see it on the photo of U-99 on page 25 of Steve Wipers book. Maybe it is located somewhere else on U-99, but I can't see anything that looks right?

Bill

NZSnowman · « **Reply #27 on:** 16 Mar , 2010, 13:32 »

Hi Bill, The location for the pitot tube seems to be different on lots of boats. I can not found any pattern yet

dougie47 · « **Reply #28 on:** 17 Mar , 2010, 15:37 »

Hi lads,

Yes, Bill, I can confirm that in all VIIB photos I have seen, there is one hole on either side of the stem. And in all VIIC photos I have seen, there are 2/3 holes on either side of the stem. Why they chose 2 on one side and three on the other is unclear. I presume they could count.

The other difference in vent patterns between B's and C's regards the main set of holes ahead of the saddle tanks - all C's had fewer holes than on B's.

Perhaps the extra holes on the stem of the C's were to compensate for the fewer holes in the main pattern? Just an idea though - I know the holes at the stem were reasonably far away from the main set of holes.

Cheers,

Dougie

Rokket · « **Reply #29 on:** 18 Mar , 2010, 05:18 »

No that this adds much useful info, but in principal, the Gatos went from HUGE "sails" ("fairwaters") and FEW flood holes ("limbers") to eventually MINIMAL faireaters and HEAPS of floods. They found that the bridge and fairwater were huge silhouettes, and cutting them don and even exposing th periscopes was best, and as for diving, more holes to vent air was better.
I assume - on different scale - the KM went through the same process. Interesting, the Gato bow view is remarkably simila to the VIIC, despite different Navies and SIZE. And really, the 2 silhouettes aren't THAT differnet,

NZSnowman · « **Reply #30 on:** 18 Mar , 2010, 22:42 »

I just noted on one of my plans that the top of the hole is right on the 'Water Level' line, if that means anything?

NZSnowman · « **Reply #31 on:** 11 Nov , 2010, 11:07 »

Great news everyone. Dani from http://www.u-historia.com/ has just got some information from Joachim Scherneck Czech, Archives assistant in Military historical training centre of the naval college M

Pat · « **Reply #32 on:** 11 Nov , 2010, 17:29 »

Ok Simon, I've got almost all the rest of it translated, but without the original to work with, it still doesn't make much sense. The online translation programs are often too literal and so the grammar gets FUBAR. (Old WWII acronym, let me know if you don't know what it means. Related to SNAFU, only worse).

Anyway, here's what I got:

ge

Author Topic: Two marks on the hull of Type VII (Read 10513 times)

JAORSA

Don in Cincinnati

JAORSA