tommy303 wrote:This last post is interesting. Given the diesel technology used for the panzerschiffe I was always puzzled about the next class of ship, the Scharnhorsts, weren't made diesel powered with the next generation of large diesel engines - instead the Germans went back to turbines.
The problem was the next generation of diesels were not ready yet and would not be for a sufficiently long length of time to drastically delay the building time table. Unlike turbines and boilers, which can wait to be installed after a hull has already reached an advanced state of construction, diesel engines of the time needed to be completed and ready for installation very early in a hulls construction since their bedding was much more extensive and the engines needed to be installed and aligned before construction of the rest of the hull proceeded. From that point on, the hull was quite literally built around the engines.
I have read this too at the Navweaps forum, but I have serious doubts about this issue from a technical viewpoint!
From all I have read in several books and some MAN sources, all MAN two stroke double-acting Diesels, M8Z 30/44 (Bremse), M7Z 30/34 (Leipzig), M9Z 42/58 (Deutschland class), M9Z 65/95 (H-class), later M12Z 42/58 (
without auxiliary engine, with a added purge air box) and the whole VZ12 family (V12Z 42/58 and V12Z 32/44 also with a added purge air box), had no fundaments or beddings. They were completely built with tie anchors and without a baseplate. The crank shaft was "free in the air" only covered from a steel sheet box.
I can't see why you can't install engines with tie anchors later in a ship hull, because you are only in need to install the tie anchors.
Do you have material/photos or sources for your opinion?
To my sources and books the traditionalist at the K-Amt came out on top at the planing of the Panzischiffe D and E and the new destroyers, and at the end of 1933 the development money for MAN diesel engines was shortened about 80% and switched to the developer of steam turbines and especially the development companys for the high pressure steam boilers.
Also through the time with massively shortened development money MAN could develop and deliver till 1938 the M9Z 65/95 (H-class) and the M12Z 42/58 (
without auxiliary engine, with an added purge air box) . The M9Z 65/95 is an enlarged PBB engine with the disadvantage that one engine has the weight of 225ts and was in need of an auxiliary engine. The MI for the H Class was about 5200 ts compare to 2700ts of BS with steam turbines. The M12Z 42/58 (
without auxiliary engine, with a added purge air box) was the first innovation (1935/36) because it wasn't in need of any auxiliary engine.
The real brake through came 1938, after the development money for MAN diesel engines was massively increased through the many problems with the high pressure steam turbines (SH/GS and all destroyers), with the construction and building of the V12Z 42/58 and V12Z 32/44 with an added purge air box.
This were two stroke double-acting 24 cylinder V engines
The VZ12Z 42/58 runs first time on a test stand 1939 and the V12Z 32/44 1940.
For comparison.
V12Z 42/58; 15.600 PSe continuous ; 8,75 power/weight ratio kg/PS; 136,5ts weight; built 1
V12Z 32/44; 10000 PSe continuous (12.500 continuous turbo charged); 5,10 power/weight ratio kg/PS; 50,8ts (60ts turbo charged) built 4, one you can see at the Museum at Sinsheim.
M9Z 65/95; 15.000 PSe continuous ; 15,00 power/weight ratio kg/PS; 225ts weight (built 6-8)
To my opinion the K-Amt gave away near 4 years of development time with the decision to change horses at 1933, we don't know when the VZ12 family could be ready, if the K-Amt hadn't changed horses and had supported fully MAN, but to my estimation at the end of 1936 the VZ12 family could be ready, especially V12Z 32/44. The true innovation was 1936 with the added purge air box, which makes the auxiliary engine unnecessary, the rest is engine development from known engines.