Search found 627 matches

by Bill Jurens
Thu Sep 19, 2019 8:14 pm
Forum: Bismarck General Discussion
Topic: FYI: meaning of the notation of the draft measurements during Bismarck’s trial runs, fall 1940
Replies: 28
Views: 749

Re: FYI: meaning of the notation of the draft measurements during Bismarck’s trial runs, fall 1940

That's an interesting question. In practical terms, I don't think that fuel oil quality would have affected trial results at all, or at least not in any meaningful fashion, as -- provided one is willing to equate 'quality' with 'efficiency' -- all that would happen would be that poorer quality fuel ...
by Bill Jurens
Tue Sep 17, 2019 4:27 pm
Forum: Naval Weapons
Topic: American SH shells - Famed or Folly
Replies: 12
Views: 4704

Re: American SH shells - Famed or Folly

It's very difficult to make other than general predictions -- one might say VERY general predictions -- particularly as in the case of side armor, target angle has a significant influence on outcome, and because no formal tests were ever made. One can calculate what various designers probably THOUGH...
by Bill Jurens
Mon Sep 09, 2019 9:03 pm
Forum: Bismarck General Discussion
Topic: It's up to you
Replies: 3
Views: 432

Re: It's up to you

No commentary at this time, just a system test...

Bill Jurens
by Bill Jurens
Tue Aug 27, 2019 10:34 pm
Forum: Bismarck General Discussion
Topic: Battleship Bismarck: A Design and Operational History
Replies: 59
Views: 8973

Re: Battleship Bismarck: A Design and Operational History

I am, at this point, locking the thread.

Bill Jurens
by Bill Jurens
Tue Aug 27, 2019 8:38 pm
Forum: Bismarck General Discussion
Topic: Battleship Bismarck: A Design and Operational History
Replies: 59
Views: 8973

Re: Battleship Bismarck: A Design and Operational History

As moderator of this forum, I can see where future action on my part to bring the discussion further under control might (and almost certainly would, by some) be interpreted as acting primarily in my own self-interest, as an attempt to stifle critical commentary. I have therefore consulted Mr. Rico ...
by Bill Jurens
Mon Aug 26, 2019 11:50 pm
Forum: Off Topic
Topic: USS GRUNION DAMAGE
Replies: 2
Views: 431

Re: USS GRUNION DAMAGE

The picture is nice, but would have to see a much more detailed illustration, and preferably some original imagery, to provide any sort of coherent commentary.

Bill Jurens
by Bill Jurens
Sat Aug 24, 2019 10:41 pm
Forum: Bismarck General Discussion
Topic: FYI: meaning of the notation of the draft measurements during Bismarck’s trial runs, fall 1940
Replies: 28
Views: 749

Re: FYI: meaning of the notation of the draft measurements during Bismarck’s trial runs, fall 1940

One thing being ignored here, or at least minimized, is the rather dramatic effect of propeller efficiency. Especially if one is running close to the cavitation limit, which Bismarck would almost certainly have been during high-speed trials, even a small defect in blade geometry can affect the speed...
by Bill Jurens
Sat Aug 17, 2019 8:49 pm
Forum: Naval Technology
Topic: Question For Bill Jurens & All Re Barrel Length
Replies: 8
Views: 809

Re: Question For Bill Jurens & All Re Barrel Length

BuckBradley asked: "To what extent can lengthening the barrel of a relatively small caliber gun compensate for BEING a realitively small calibre gun? Could I turn a 37mm into a Tiger-killer just by making the barrel long enough and putting more powder in the cartridge?" My apologies for the delayed ...
by Bill Jurens
Thu Aug 15, 2019 5:25 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2718

Re: 3-shaft propulsion

For some reason the number three does not seem to work well regarding propulsion systems. Number of three-legged animals? Pretty small, perhaps non-existent. Number of three-engined airplanes? Not many left of those. Number of three-wheeled automobiles? Again, not too many. Number of three-engined s...
by Bill Jurens
Wed Aug 14, 2019 12:24 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2718

Re: 3-shaft propulsion

There is an interesting article in the Journal of the American Society of Naval Engineers for May 1901, translated from the German periodical Marine Rundschau. Author unknown. This discusses the advantages of three-shaft vs two shaft propulsion in some detail, coming down generally in favor of three...
by Bill Jurens
Wed Aug 07, 2019 9:10 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2718

Re: 3-shaft propulsion

I should make it clear at the outset, that at this point I am speaking on my own behalf, and not acting as moderator. I will insert commentary between asterisks... Pasoleati wrote: "Mr. Jurens's response flies against everything that solod historiography is. For example, the very basic foundation of...
by Bill Jurens
Wed Aug 07, 2019 5:20 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2718

Re: 3-shaft propulsion

Pasoleoti wrote: "A bit strange statement for how could someone have any legal reason to prevent anyone publishing such data for I doubt the data is any longer secret...And if someone wishes to keep the data secret just because, that someone belongs to 6' under." Well, the death penalty for this sor...
by Bill Jurens
Wed Aug 07, 2019 4:35 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2718

Re: 3-shaft propulsion

No need to compute Bismarck hull resistance from scratch. The towing tank test results have survived. I'm not at liberty to post them, though, and I'm not entirely sure it would be productive to do so.

Bill Jurens
by Bill Jurens
Wed Aug 07, 2019 2:05 am
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2718

Re: 3-shaft propulsion

Mr. Malara is dancing around some of the key parts of the problem, namely figuring out some way to reduce the speed of the turbines, which are happiest at high speed, to suit the propellers, which tend to be happiest as the speed goes down. The Germans and the British used only single reduction gear...
by Bill Jurens
Sun Aug 04, 2019 7:08 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 115
Views: 2718

Re: 3-shaft propulsion

Manufacturing and maintenance issues aside, there is always at least a theoretical increase in efficiency as the difference in temperatures between the working fluid, in this case steam, and the thermal sink, in this case seawater, gets greater. The general equation for theoretical efficiency -- bas...