Bismarck vs. Iowa

Historical what if discussions, hypothetical operations, battleship vs. battleship engagements, design your own warship, etc.
Bgile
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Post by Bgile » Fri Mar 24, 2006 12:54 am

Karl Heidenreich wrote:In terms of armour, then, Iowa has a better upper belt than Bismarck, but the main belt is even between these fictional contestors, isn´t it? Also, the citadel part of both ships is heavily armoured and there is no radical advantage from one over the other?
The difference will be in terms of speed (Iowa is faster than BismarcK) and with long range fire (16" against 15"). The Bismarck will have to play the Hood part of Denmarck Straits trying to approach as much as possible to Iowa, then?
I would think so, yes. Close range would favor Bismarck.

Just to clarify, Iowa has no upper belt, per se. Bismarck has more volume behind some armor than Iowa. But the upper armored area of Bismarck is not protected against battleship fire. Also, Bismarcks lower citadel area containing the engineering spaces is better protected against short range fire than Iowas is.

To rephrase: It is effectively impossible to penetrate into Bismarck's engineering spaces and main gun magazines with close range gunnery because of the arrangement of the armor and the fact that a shell would have to penetrate the turtleback after it got through the main belt.

On Iowa and most other schemes, once you penetrate the main belt there is no significant amount of armor behind it.

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miro777
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Post by miro777 » Fri Mar 24, 2006 3:05 pm

hey
so bismarck vs. iowa -----> pretty even

so lets expand that
lets say that the german side gets a Scharnhorst and the Allied side to Country cruisers.
Would the german BC hold of the two cruisers?

adios
miro
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Bgile
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Post by Bgile » Fri Mar 24, 2006 6:12 pm

miro777 wrote:hey
so bismarck vs. iowa -----> pretty even

so lets expand that
lets say that the german side gets a Scharnhorst and the Allied side to Country cruisers.
Would the german BC hold of the two cruisers?

adios
miro
Remember - we are assuming NO RADAR for Iowa. The ship was designed to fight at 25kyds+.

Scharnhorst quickly destroys the cruisers or ignores them and turns on Iowa.

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Karl Heidenreich
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Post by Karl Heidenreich » Fri Mar 24, 2006 8:15 pm

Miro:
so lets expand that
lets say that the german side gets a Scharnhorst and the Allied side to Country cruisers.
Would the german BC hold of the two cruisers?
Let´s better not. The whole idea is to have one BB against other BB. But we have already stripped the Iowa of her main advantage, her radar. If we continue to expand the scenario we will end with something that hasn´t anything to do with the original idea. As far as I understand it we have a duel now; more ships then we have a fleet action. Many old "ifs" will go and another and different ones will come.
Best regards.

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miro777
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Post by miro777 » Sat Mar 25, 2006 5:10 pm

hey
yeah but as we found out earlier we got the conclusion that the Iowa (without her radar) would be even against Bismarck.
so that's why i expanded.

kk
adios
miro
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Biz vs Iowa

Post by turlock » Tue Mar 28, 2006 11:24 pm

I'd just like to point out that there was no armor anywhere on Bismarck that would keep out Iowa's AP shell. Nowhere. Long range, short range, Biz would be riddled. The Iowa's immunity zone at 25 K yards would keep out the old 2240 pound AP shell of the Maryland class.
The Italian 15 inch was a quantum leap in muzzle energy over it's contemporaries, greatly surpassing the German weapon in energy. It outclassed the older 16 inch rifles on Rodney and Maryland. Unlike the earlier U.S. Mark 6 16 inch, the Iowa's Mark 7's were, and still are considered to be excellent naval rifles. Your scenario here is of Bismarck fighting a ship whose main armament is a quantum leap more powerful.
And, though it has nothing to do with a WW2 scenario...Iowa goes down in history, now that they are all stricken, as the best shooting battleship of all time. At a range purportedly to be 47,000 meters, using specially selected hand packed powder charges, in experiment to test the maximum theoretical accuracy of the rifle, some 5 out of 6 rounds from a six gun salvo struck a schoolbus sized target. ..about a 20 meter long target. Most of you have probably never hunted, but such accuracy is about on par with the finest varmint rifle using hand loads.
I'm not trying to antagonize any of you, but it does seem to me that in reading posts about the Iowa's that many just don't understand that the American 16/50 cannot be compared to other sixteens. It was just simply superior to all of them, and that includes the H class guns. Put those guns in a hull designed to withstand normal sixteens at average battle ranges, and sight them with the optical fire control that was probably every bit as good as the Germans, and Iowa will make a sieve out of Bismarck I'm sorry, but it's the truth.
Bismarck was hard to sink, but it proved remarkably easy to neutralize her main armament.

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Karl Heidenreich
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Post by Karl Heidenreich » Tue Mar 28, 2006 11:48 pm

Turlock wrote:
it does seem to me that in reading posts about the Iowa's that many just don't understand that the American 16/50 cannot be compared to other sixteens.
I think that you´re probably right. At least, speaking for myself, never give a thought to the fact that the 16"/50 Mark 7 gun-shell was so superior to the Rodney´s own 16". When speaking of 16" shell damage I was thinking in the Rodney gun fire effect on Bismarck at her last battle.
Is it there some information if armour penetration of this kind of gun against an armour comparable to Bismarck´s?

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Post by Bgile » Wed Mar 29, 2006 2:38 am

The US 16" was extremely powerful and it could penetrate Bismarcks turret faces at pretty much any range. However, the side armor + turtleback + holding bulkhead made it pretty much impossible to penetrate into the engineering or magazine spaces at short range. Nathan Okun calculated that if you put one of Yamato's 18" guns against Bismarck's hull, you might just barely be able to penetrate it.

To rephraze: You can hit below the belt as PoW did at ranges of 20K or so, and at very long range penetrate the two decks, but nothing can penetrate the horizontal SYSTEM at short range in it's entirety and get into the engineering or magazine spaces. There is no evidence from the final battle that any did.

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Karl Heidenreich
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Post by Karl Heidenreich » Wed Mar 29, 2006 3:54 pm

But again: wasn´t that Rodney´s 16" that were not capable to penetrate the Bismarck´s armour? If we put an Iowa instead of the Rodney, doesn´t that make the difference?
In previous topics there were these arguments about Yamato´s 18" vs. Iowa´s 16" and the general idea was that Iowa´s was superior to Yamato. If this idea is right (only if) then that Yamato can´t penetrate the side armour doesn´t mean that Iowas can.

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Post by Bgile » Wed Mar 29, 2006 4:43 pm

This is from http://www.navweaps.com :

"The 46 cm/45 (18.1") cannons used on the Yamato class were the most powerful guns ever installed on a battleship. While closely matched by the USA 16"/50 Mark 7 at long ranges, in a short-range engagement this weapon had no equal. The muzzle blast is said to have been able to rip the clothes off personnel who were standing too close when the guns were fired, but this story is probably apocryphal. These guns were officially designated by the Japanese as "40 cm/45 Type 94" (15.9 inch) in an effort to hide their actual size, which was a closely-guarded secret until after the end of World War II."

I suggest further reading on this site; it's an excellent reference.

The reason I suggest Bismarck is derived from Baden is that if you look at an armor cross section it is very similar. I believe Baden also has 3 shafts, and 4 / 15" guns. Neither ship bears any resemblance to Graf Spee whatsoever.

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Karl Heidenreich
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Post by Karl Heidenreich » Sat Apr 01, 2006 5:57 pm

Hi Bgile: That adds very much.

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Post by Djoser » Sat Apr 15, 2006 11:52 am

That is interesting--all the data I have seen ranked the Yamato 18's and the Iowa 16's about even--but it always sounded a bit too good to be true...

Not that I doubt the amazing effectiveness of the Iowa class main battery for a second.

Thanks for the information, and the link, Bgile.

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Post by Karl Heidenreich » Tue Apr 18, 2006 10:29 pm

From Bgile:
This is from http://www.navweaps.com :

"The 46 cm/45 (18.1") cannons used on the Yamato class were the most powerful guns ever installed on a battleship. While closely matched by the USA 16"/50 Mark 7 at long ranges, in a short-range engagement this weapon had no equal. The muzzle blast is said to have been able to rip the clothes off personnel who were standing too close when the guns were fired, but this story is probably apocryphal. These guns were officially designated by the Japanese as "40 cm/45 Type 94" (15.9 inch) in an effort to hide their actual size, which was a closely-guarded secret until after the end of World War II."

I suggest further reading on this site; it's an excellent reference.

The reason I suggest Bismarck is derived from Baden is that if you look at an armor cross section it is very similar. I believe Baden also has 3 shafts, and 4 / 15" guns. Neither ship bears any resemblance to Graf Spee whatsoever.
O.K. The part about the Yamato´s 18" gun makes perfect sense to me. Being the biggest naval gun ever mounted on a ship (with the obvious purpose of blowing anything else out of the water, big or small) it outgun any other ship´s armament. The curious thing is this
in a short-range engagement this weapon had no equal.
So, ambiguity again: what happens with long range, plunging fire? Is Yamato´s 18" still the greatest or the Iowa´s 16" Mark 7 superior? Isn´t there a table with comparison between these two guns?
About Bgile´s argument in favor of the Bismarck´s Bayern-Baden Class genealogy I have to say that his argument makes sense also. If we see the Bismarck and Graf Spee it´s there are no common lines that associated them. Probably we can say that Graf Spee and Bismarck were part of the same German warship development (the 1930ies). Then Bismarck´s is a design that owes some general characteristics to the Bayern-Baden Class, which is hardly saying that Bismarck is a Baden heir.

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Post by Bgile » Tue Apr 18, 2006 11:34 pm

Karl Heidenreich wrote: So, ambiguity again: what happens with long range, plunging fire? Is Yamato´s 18" still the greatest or the Iowa´s 16" Mark 7 superior? Isn´t there a table with comparison between these two guns?
From the ballistics tables it appears to me that the 18.1" gun is superior to the 16" Mk 7 at all ranges, and I don't know why they say that. It's a puzzle. US radar controlled fire should be better at long range, but that has nothing to do with the weapon itself.

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Post by Gary » Wed Apr 19, 2006 12:18 pm

No-one can say that Iowa wasnt a first class ship.
However in Short range North Atlantic combat, Bismarck must not be counted out to easily.
On paper you would expect Iowa to win but then on paper Hood and POW should have defeated Bismarck in the Denmark strait.
God created the world in 6 days.........and on the 7th day he built the Scharnhorst

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