Iowa Class: Armor Protection

Warship design and construction, terminology, navigation, hydrodynamics, stability, armor schemes, damage control, etc.
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Karl Heidenreich
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Re: Iowa Class: Armor Protection

Post by Karl Heidenreich »

yellowtail3:
I promise never to rediculize anyone. But on this Iowa Class Gospel: what does it say, and where can I find it?
I do apologyse, yellowtail3, for this stupid remark of mine to which you are refering. I must learn NOT to post when I´m in a particular stressfull moment at work: every time such thing has happened I post idiotic answers to people who I imagine are antagonizing me. My fault and I recognize it. lwd , Lutscha and Bgile are very inteligent guys that know a lot, with I would very much like to invite some beers if the occassion raises: we differ in certain things and that´s all.

Now:

About the difference of sources of books and internet my position do not change: I still feel that a good book superseeds internet sources. An internet source could be deleted or could come, as with the forums, from anonimous sources or could be misleading more easily than in another format. I do recon that in the book format serious idiotics also publish and that criteria, research and care are necesarry when you are gathering info. Still, as I state, the book cannot be deleted overnight to say something different later. That is why, when you contract a building or whatever, the hard signed copies of specifications and drawings are the legal documents to attach to a contract, whilst the electronic files are just for reference.

I hope I have explained myself in this issue and do ask apologies for my previous not so inteligent post.

Best regards,
Last edited by Karl Heidenreich on Thu Dec 10, 2009 12:56 am, edited 4 times in total.
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Karl Heidenreich
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Re: Iowa Class: Armor Protection

Post by Karl Heidenreich »

yellowtail3:
Formidable &useful ships, those Iowas.
Just for the record: I saw USS Iowa firing her main battery in 1986 when she visit Costa Rica during the bitter years of the guerrilla wars of Central America.

Useful: yes, they were. But I interpret this in the same way I regard the Sherman tank, they play their part of the very clever and "organic" doctrine the US designed to win WWII. About the ship itself, as with the Sherman, I have been learning that she wasn´t the epitome she is always regarded but I´m not yet in position to do a comprehensive exposition of this. Maybe after December.

Best regards,
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lwd
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Re: Iowa Class: Armor Protection

Post by lwd »

Karl Heidenreich wrote: ..About the difference of sources of books and internet my position do not change: I still feel that a good book superseeds internet sources.
The counter to this would be to look at what some of the better authors are doing. For instance the authors of Shattered Sword have posted updates and/or corrections on line. Which then is the better source? There are also very good books which contain errors for various reasons that have since been corrected. As pointed out earlier most books that discuss of the Kirishima's demise mention 9 or 9+ hits by Washington's main battery. Currently there is a discussion of the damage to her on line that goes into detail on how many hits there were and where. Which supersedes which?
An internet source could be deleted or could come, as with the forums, from anonimous sources or could be misleading more easily than in another format.
Much the same could be said of books. Ie the source may no longer be available or anonimuos. As for misleading potentially but on the otherhand it is often easier to check on internet sources. In particular forums such as this one where you get numerous people discussing/argueing the issue and supporting their arguments with both paper and electronic references make it more difficult rather than easier to mislead.
That is why, when you contract a building or whatever, the hard signed copies of specifications and drawings are the legal documents to attach to a contract, whilst the electronic files are just for reference.
This is not always the case anymore. Electronic files are being used more and more as documents of record. They require digital signatures and/or other forms of verification but they are being used. Furthermore while one can change the data on a web page there's a very good chance especially if the page was up for any length of time that copies of it exist. It's getting harder to weasel out of things that way.
I hope I have explained myself in this issue and do ask apologies for my previous not so inteligent post.
None of us post at our best when we are tired or stressed and all of us do it on occasion. As far as I'm concerned there was little to apologize.
Thorsten Wahl
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Re: Iowa Class: Armor Protection

Post by Thorsten Wahl »

i made a superficial calculation on armorweight according to the data in post 1

all weights metric tons


Armor overall 23.347
Armor citadel 13.090

all calculated

Armorweights

horizontal citadel total 9.282

Deck 1 1799,3
Deck 2 5049 Class B
Deck 2 1328,7 STS plate
Deck 3 356,1


vertical citadel total 3.808

fore plating 410
Main belt 3398


torpedoprotectionn total 3.468

T-bulkhead 1 427
T-bulkhead 2 427
underwater belt 2187
Holding bulkhead 427


armor main artillery total weight 3.752

T1 Turretarmor 635
T1 Barbette 477
T1 Turretarmor 635
T2 Barbette 893
T1 Turretarmor 635
T3 Barbette 477


other artillery 250


transversale Bulkheads total 811

Transv.-Bulkhead bow 338
Transv.-Bulkhead stern 473



Further armor total weight 1.977

command tower 500
other comand 100
stern/rudder plating 1350
Transversale bulkhead rudder 27

superstructure unknown
bow plating not calculated
stern plating not calculated
structural/hull unknown

seems very high, are there any suggestions for corrections
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Juan
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Re: Iowa Class: Armor Protection

Post by Juan »

Hello everyone,
when judging a bb design we must take into account that each ship is designed for a determinated theather or operations, in the case of Bismarck it was designed to operate in thte north atlantic where common battle ranges where 15000-20000 meters, so it armour was designed to withstand the risk of fighting at this ranges also the surviability of the ship must be ensured by compartimentation because the germans had so few ships, and if a 32 mm deack was enough to iniciate the fuze of a bomb a 50mm will be equal or best also if the spacing between them is greater the chances of the bomb detonating before it reaches the main deck is better.

Juan
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Re: Iowa Class: Armor Protection

Post by alecsandros »

Hello Juan,
A growing volume of very good quality research shows that Bismarck class was protected against 15" fire up to 30km. The 50/80 + 80/100mm spaced array armored decks were capable of stoping or rendering inert most of the BB shells available in the war, at all practicle fighting ranges.

Cheers,
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Karl Heidenreich
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Re: Iowa Class: Armor Protection

Post by Karl Heidenreich »

alecsandros:
Hello Juan,
A growing volume of very good quality research shows that Bismarck class was protected against 15" fire up to 30km. The 50/80 + 80/100mm spaced array armored decks were capable of stoping or rendering inert most of the BB shells available in the war, at all practicle fighting ranges.
:ok:

Also there are doubts on the efficiency of the upper armoured deck of the South Daks and Iowas of "just" 38 mm.
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lwd
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Re: Iowa Class: Armor Protection

Post by lwd »

Karl Heidenreich wrote:... Also there are doubts on the efficiency of the upper armoured deck of the South Daks and Iowas of "just" 38 mm.
Just what do you mean by this? From what I've read the main purpose of the upper armored deck was to initiate the fuse of AP bombs. Are you saying 38mm was inadequate to this task?
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Dave Saxton
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Re: Iowa Class: Armor Protection

Post by Dave Saxton »

Karl Heidenreich wrote:
Also there are doubts on the efficiency of the upper armoured deck of the South Daks and Iowas of "just" 38 mm.
Although true, it was not heavy enough to de-cap large caliber APC, and the inter-space was too small to unsure detonation of time delayed AP before reaching the main armour deck, it was still an essential element to the over all deck protection against large amour piercing artillery shells. In a June 1941 memo from the BoO to to Carngie Steel the true purpose of the 38mm upper deck is revealed. It was a yaw deck. By yawing large caliber APC it required greater velocity for the shells to penetrate the main armoured deck, or in other words by yawing the shells even slightly it increased the effective thickness of the main armoured deck. Yaw created by the spacing above of the upper deck 38mm armour was an essential feature of the US fast battleship deck protection and also had desirable properties against SAP bombs or non AP bombs.
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RobertsonN
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Re: Iowa Class: Armor Protection

Post by RobertsonN »

Were the Americans able to quantify the effects of yaw, so that they were included in the upper edge of the immunity zone?
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Re: Iowa Class: Armor Protection

Post by lwd »

Dave Saxton wrote: ... . In a June 1941 memo from the BoO to to Carngie Steel the true purpose of the 38mm upper deck is revealed. It was a yaw deck. ...
That's still speculation and rather unwarrented from what I've seen. The upper armored deck as a bomb deck seems to predate the yaw inducing experiments you mention earlier.
http://books.google.com/books?id=Y41Ha_ ... or&f=false
Describes it as such in designs dating to the mid 30's. The fact that only one thickness is quoted in the test you mention suggest that the test were simply to see what additional benefit was to be gained and not an attempt to determine what the benefits were.
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Re: Iowa Class: Armor Protection

Post by Dave Saxton »

RobertsonN wrote:Were the Americans able to quantify the effects of yaw, so that they were included in the upper edge of the immunity zone?
It looks like the USN did come up with a reasonable estimate of the improvement due to the yaw deck in their IZ calculations from the beginning, if the IZ was to be 31,000 yards vs the Wee Vee 16" shell (or in the case of NC the 14"/50 to 28k). The IZ spec isn't meant otherwise, due to the laminated main deck and using the USN's period methodology for calculating laminated armour.

Yaw can't be strictly quantified. Even today it is usually expressed as a range; ranging from 10% more V to as much as 30% more V required. Kratz in ADM213/951 says that breaking it down and looking at it plate by plate combined with residual V, remaining mass, striking angle, and factoring in nutation and precession is too complicated. Other Krupp experts instead used a methodology for spaced plates which accounted for relative plate quality, the interaction of particular classes of shells with classes of armour, the ratio of plates thickness, capped or uncapped shells ...ect...

Another way of looking at yaw requiring more V for penetration, is that instead of the main plate having a greater effective thickness is that it has a greater relative quality compared to standard.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.
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