Hello, I'm happy to be a part of this great thread.
I'm interested in the weponary especially, "
15 cm/55 SK Drh.L.C/34" secondary twin turrets used by Sharnhorst-class, Bismarck-class, H-class battleships and M-class cruiser.
https://www.artstation.com/artwork/eJwJZX
Two turrets have survived the war and now reside in the Stevnsfort. But after examining the interior photos taken by tourists, I have noticed that many of the internal fittings are not originals (especially back wall mountings). Refer to the drawings from "
Unterrichtstafeln für Geschützkunde - Band 1: Seeziel".
https://forum.axishistory.com/viewtopic.php?f=70&t=83669&start=45
Especially the "Firing control panel" on the back side was completely removed (term from "The Battleship Bismarck [Anatomy of The Ship]")
The configuration of the original interior fittings on the backside of the wall and their functions are mystery which i wanna research.
Visualizing the original intended structure will help understanding the intention of the German builder.
Does the bundesarchive have the documents related to the turret?
Any blueprints, drawings and the interior photos are greatly appreciated which are not from "Unterrichtstafeln für Geschützkunde - Band 1: Seeziel"
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General info
Differences between Bismarck and Sharnhorst class's 15 cm twin turrets
- Armour thickness
Scharnhorst: front 140mm; sides 60mm, rear 70mm, roof 30-50mm
Bismarck: front 100mm; sides and rear 40mm, roof 20-35mm
Source: "The Battleship Bismarck (Anatomy of The Ship)", "The Battleship Sharnhorst (Anatomy of The Ship)", RM 20/1913
- External appearance
There are rivets joining the sides and back plates in Bismarck's but not in Scharnhorst's
There are rivets along the bottom edge in Bismarck's but not in Scharnhorst's
A pair of fitting on the frontal plate between the guns (Cylindrical vs Button shape).
Source: No source, Just compared the photos from Bundesarchiv.
15 cm twin turret composition on the German battleships.
- Sharnhorst-- 4 x long shaft "15 cm/55 SK Drh.L.C/34 turret"
- Bismarck---- 2 x long shaft, "15 cm /55 SK Drh.L.C/34 turret", 4 x short shaft "15 cm /55 SK Drh.L.C/34 turret"
- H-class------ 2 x long shaft "15 cm /55 SK Drh.L.C/34 turret", 4 x short shaft "15 cm /55 SK Drh.L.C/34 turret"
For Bismarck and H-class only the forward one had the long turret.
The others were located at the edge of the ship right above the Turtle-back armour. It creates slanted armored deck making the turret
to be one level shorter unlike the forward turret which is located closer to the middle-line.
Source:"The Battleship Bismarck (Anatomy of The Ship)"
Levels of the turret
Long shaft: Gun house level - Train mechanism level - Machinery level - Workshop level - Ammunition handling level
Short shaft: Gun house level - Train mechanism level - Machinery level -
(Workshop level + Ammunition handling level)
For the short shaft, Workshop level and Ammunition handling level became one.
https://samlinger.natmus.dk/fhm/asset/210109 you can see the screw at the bottom and welding point on the top looks odd.
Source: "The Battleship Bismarck (Anatomy of The Ship)", "The Battleship Sharnhorst (Anatomy of The Ship)"
Coastal bunker type
There were two types of coastal bunkers which can house those 15 cm twin turret mounts.
The "M184" and "M219". "M184" was one level shorter than the "M219".
M184 was intended to use the surplus short turrets of the H-class battleship.
Whearas M219 was intended to house "Drh.L.C/34 turret". The long shaft turret.
Source:
https://www.lexikon-der-wehrmacht.de/Regelbauten/Mittelbatterien.htm
https://www.lexikon-der-wehrmacht.de/Regelbauten/Marine/RBM184.htm
https://www.regelbau.dk/regelbau_visbunker.asp?id=294
What's interesting is that bunker of the Fanø (the turrets are now in Stevnsfort) was
"M184" type which cannot accomodate the long shaft of the Gnei's secondary turret. A document found in the Bundesarchiv tells more about this story.
"Buildings of permanent fortifications Batt. Graadyb work stopped because planned turrets are not coming to Fanö. Reconstruction of towers in terms of fortress construction and weapons technology (shortening of the tower core) is underway"
Source: BA-MA, RM 31/3215 (All the credit goes to a member from "Axishistory" forum)
The expected turret might be the short turret of the H-class battleship mentioned above.
One that had been shortened must be Gnei's.
Examples
Location------------------------bunker type----------------------------turret mount-------------------------------------origin
Petsamo (Finland)------------2 x M219 bunker-----2 x long shaft, "15 cm /55 SK Drh.L.C/34 turret"-----------------H-class
Sylt (Germany)---------------2 x M184 bunker-----2 x short shaft, "15 cm /55 SK Drh.L.C/34 turret"-----------------H-class
Borkum (Germany)-----------2 x M184 bunker-----2 x short shaft, "15 cm /55 SK Drh.L.C/34 turret"-----------------H-class
Den Helder (Netherlands)----2 x M219 bunker-----2 x long shaft, "15 cm /55 SK Drh.L.C/34 turret"-----------------Gneisenau
Fanø (Denmark)---------------2 x M184 bunker----2 x short
(modified) shaft, "15 cm /55 SK Drh.L.C/34 turret"----Gneisenau
Some of them are complete or partially built.
Second hand reference:
https://forum.axishistory.com/viewtopic.php?t=201637
https://forum.axishistory.com/viewtopic.php?f=70&t=83669&start=30
15 cm twin Turrets and Gun's serial numbers
Turret number
Sharnhorst: Turret number: #1 ~ #4
Gneisenau: Turret number: #5 ~ #8
Gun number
Sharnhorst: 1000 ~ 1007
Gneisenau: 1008 ~ 1015
1. Den Helder
Turret #6, Gun Sn# 1008, 1010
Turret #8, Gun Sn# 1012, 1014
2. Fanø (Stevns):
Turret #5, Gun Sn# 1009, 1011
Turret #7, Gun Sn# 1013, 1015
Source: http://www.atlantvoldsydvest.dk/2022/02/13/dokumentation-af-gneisenaus-kanoner-i-danmark-1944-2021/
Update
2023.10.17 - The rear armour thickness of the Gnei's turret has been chnaged from 60 mm to 70 mm (RM 20/1913)
2023.10.17 - Replaced the "C/28 turret" to ""C/34" following the the manuals (RM6). (
List 1, 2 jpg)
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