Shipbucket

Very interesting stuff. I can't comment on the design but the drawing is beautifully executed as usual.

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I share your pain, even official sketches and plans can leave you scratching your head and wondering how to make sense of conflicting information on side and top views.
I would bet for a more modest South Dakota-esque skeg, after all wouldn't having all three rudders enclosed like this make any kind of manoeuvring a nightmare (especially in harbour etc.)?

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My question would be, which propulsion unit were they planning? Diesel only, Steam only, or mixed Diesel/Steam?

If it is the mixed unit I would expect the two outer shafts to be used for cruising and diesels, while the centre shaft would be the steam plant only brought online for high speed runs. In which case the middle skeg would have the rudder and screw built into it as the skeg would act as a streamlining tool when the centre shaft & rudder were not required.

To me, looking at the plan view, the propeller blade protrudes outside of the skeg. Protecting the prop shaft but not the prop itself.


Tempest.

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Thanks for all the feedback!

I still don't know what to do with this...

While I fully agree with you guys, that a skeg layout similar to SoDak would be the most sensible and logical option, I'm still a little sceptical.

I don't understand why all (of the few) sources point out, that the skegs were designed after the fatal rudder damage of Bismarck became known.
How would a layout such as SoDaks' enhance the protection of the screws and the rudders? The rudders are as susceptible to torpedo damage as on the earlier BBs.


Also, all line-drawings of the H42,43 & 44 show an identical skeg / fin arrangement. This makes me believe that there could be something more to it than a drawing error.


The article apdsmith linked to by Stuart Slade has some interesting info and opinions about the skegs on German BB proposals:
A small bit I found on German-Navy.de about the H42 mentions the fins and their intended purpose and practicability:



@Krakatoa:
You are correct, a mixed Diesel / steam turbine propulsion was envisioned.

H41 design finalized by july-november 1941, The finalized design was approved by Admiral Raeder on 15 November 1941

Sources/refs for H42, H43, H44 are incomplete & sometimes extremely "dubious" (I have major & definitive doubts about secondary, tertiary and light AA guns on H44). You can attempt to draw all of them, but I feel a very hotly debated topic on shipbucket

Thinking about the mixed propulsion with a 3 screw installation. I have had a quick play with that.




I would think the centre screw would be bigger than the outer two. The outer shaft/screws only have to handle ? 60,000shp for a top speed of about 20 knots? The centre shaft screw has to handle the other 160,000shp to take the ship to the 32 knot top speed.

The centre shaft/screw would spend a lot of time freewheeling, with the rudder centred and not interfering with streamlining efficiency.

Or would it be the other way round?

Or it could be like I have seen some merchantmen with the aft end of the skeg operating as a rudder.

Krakatoa,
Larger ? skegs for the outboard shafts

Still scratching my head on this one.
On the basis of maomatic's textual quotes it seems the original all-enclosed H41 drawing may have been correct. I still can't get my head around how the skegs enclosed the outer propellers and rudders unless the stern of the ship was much fatter than shown in the plan drawing.
It just seems madness, why would a totally enclosed skeg layout require three rudders if all are enclosed? They would all be equally ineffective. I'm presuming a twin rudder layout like Bismarck's was abandoned because it would not fit inside a skeg, so how would three rudders fit?

How accurate is that source drawing? Is it based on real plans or post-war artistic interpretation of textual/ verbal accounts of what was intended?

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Hello everyone

For what my gut feeling is worth: the source drawing is just plain wrong. It looks like the one from Breyer's 1970 book on battleships, and would not be the only error there (he consistently confused the number of shafts on German WWI capital ships, showing three on Von der Tann and Moltke and four on Nassau in the top view rather than the other way around as would have been correct). With the flank screws shown so far outboard on the source, the skeg would have to curve inboard behind the screw even if one assumes the screw to be placed in a hole in the skeg itself - which seems slightly absurd in my view. This would only become worse if indeed all screws were placed inside two unpierced skegs. Such an arrangement would certainly waste thousands of hp due to increased hull resistance and make the ship pretty much unsteerable. Protecting the rudders in such a way without rendering them ineffective strikes me as impossible (although I'm no engineer and might be wrong).

My guess - and it's only a guess - would be that the wing shafts were planned to be longer than the center shaft, so the center shaft and at least one rudder could be placed inside two straight skegs with propellers at their ends. The other rudder - or rudders - would have to be placed aft, unprotected. This one would not provide complete protection, but at least some credible reserve in case of damage. But as the project was never taken seriously by the German Navy anyway (reportedly it was only pursued to prevent the personnel involved with it from being sent to the East Front), it might just be that no one really cared if the skeg configuration is feasible or not.

Greetings
GD