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Thread: Iowa horizontal protection (over magazines)

  1. #16
    Defense Professional RustyBattleship's Avatar
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    Quote Originally Posted by Radical View Post
    I just found the plans. These are great and I didn't even know they existed. Thank you very much for the reference. It seems like most of the strakes in the bow at 25# (0.625") MS. Is there a reason for using Mild Steel instead of HTS or STS in the bow section? Since it looks quite thin I would have thought that it used thicker plates.
    We were the honest guys and trying to keep within the weight limits demanded by the London Treaty. Yes, we would have liked to make it thicker, but we needed to reduce weight. However, that was also to our advantage because with a shallower draft we could sustain 30 to 32 knots.

    25.5 lb HTS plating does run several feet forward of bhd 50 and several feet aft of bulkhead 166, especially if its the shear strake that is attached to the stringer strake of the main deck.

    You will also see that almost every T bar frame has holes cut in it to reduce weight (plus it provided for cable and piping runs). The strength of a T bar or H beam is in the distance the flanges are apart. The web is thinner because its sole purpose was only to keep the flanges at their proper distance.

    The guidance of cutting lightning holes are:
    1. The hole must be no more than half the depth of the beam (unless reinforced with a welded collar).
    2: The center to center distance of the holes shall be no shorter than twice the depth of the beam.
    Able to leap tall tales in a single groan.

  2. #17
    Defense Professional RustyBattleship's Avatar
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    Quote Originally Posted by Radical View Post
    Rusty, do you know why the outer part of the deck armor is 7" (5.75" Class B + 1.25" STS) while the inner part is 6"? It seems almost counterintuitive because wouldn't the inner part cover more of the ships vitals?

    Edit: fixed math error, it's combined 7".
    You must have a blurry set of plans (I do too). Armored decks are consistant from frame 50 to 166 forming the "Armored Box" section of the hull. But the 61.2 lb STS Main deck continues to run some distance forward of frame 50 and some distance aft of frame 166.

    The second deck however is a totally different animal. The ACTUAL structural is 51 lb STS and would be perfectly sufficient as a strength deck ONLY without the addition of armor.This decking runs athwartships from the back of torpedo bhd 3 (which supports the 12.1" Class A armor OUTBOARD), It is completely WELDED in place.

    But the 4 3/4" thick Class B armor on top only runs between the Port & Stbd Holding Bhds 4. AND, it is NOT welded (sort of). It is secured to the 3rd deck by "Quilting Pins". These are a version of a "Cold" rivet. It's hard to describe by words only as it is a unique design and when I first reviewed the plans as to how they are made and installed gave me much more respect for the engineers that designed them and shipfitters who installed them back in those early post-depression times.

    But, in a nutshell, it was determined that Class B armor was not a necessary weight to add on as the past the P&S Holding bulkhead. But it is interesting (though logical) that holding bhd 4 is only 1/4" thick M.S. between Main and 2nd Decks. But below 2nd deck it is 5/8" thick STS.
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  3. #18
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    To clarify, I meant the variation of the second deck thickness. I've attached an image to show what I mean.

    Name:  iowa armor.jpg
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    The red circled part shows that the outboard part of the second deck is 5 3/4" thick Class B while the inboard part is 4 3/4" thick Class B. This is also the value I saw in Friedman's battleships book. Is there a reason for that arrangement? Interestingly, the Booklet of General Plans doesn't seem to show that the outer part of the second deck is thicker.

  4. #19
    Defense Professional RustyBattleship's Avatar
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    Quote Originally Posted by Radical View Post
    To clarify, I meant the variation of the second deck thickness. I've attached an image to show what I mean.

    Name:  iowa armor.jpg
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    The red circled part shows that the outboard part of the second deck is 5 3/4" thick Class B while the inboard part is 4 3/4" thick Class B. This is also the value I saw in Friedman's battleships book. Is there a reason for that arrangement? Interestingly, the Booklet of General Plans doesn't seem to show that the outer part of the second deck is thicker.
    I would trust the booklet of General Drawings, explicitly.

    Copied illustrations for personal publication of a book are often clarified or enhanced to make them easier for most people to read. To publish an exact copy from the booklet will only confuse 50 to 75% of the readers. But experienced Naval Architects have no problem and know what some of the symbols mean and what the arrow is actually pointing at.

    About the only thing left out in an official Navy booklet of General Plans is the thickness of strakes M & N of the outer shell plating. This was done deliberately using a "Need to Know" attitude. To find out the thickness, you have to pull up a full set of the expanded view of the shell plating which would tell you those strakes are 1.5" thick of S.T.S. installed INTO the framing and stiffeners so the outside surface is even along with the rest of the shell plating. Not only does this make water flow better but it also hides the fact that it is part of our side armor.

    Even then that expansion plan is brain teasing to read and brain boggling to draw as it shows all of the plating of one side of a ship (usually stbd side) from the centerline keel to the highest edge of the sheer strake totally FLATTENED out with no curves at all such as the bilge strake.

    But there are some very logical reasons for that. Which I'll go through aome other time.
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  5. #20
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    Interestingly, both Friedman, and Garzke and Dulin book both list the outer part of the 2nd deck as having 5 3/4" class B. Wonder where that figure came from for multiple books to list that. The South Dakota class also has slightly thicker second deck on the outboard part. I just find it odd that the general plans doesn't show this alleged difference. Also, the general plans don't seem to show the thickness of the Class A and Class B belt either.

    Also, the New Jersey plans below label Stakes M and N as 60 lb STS. These look official to me.

    http://maritime.org/doc/plans/bb62.pdf

  6. #21
    Defense Professional RustyBattleship's Avatar
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    Quote Originally Posted by Radical View Post
    Interestingly, both Friedman, and Garzke and Dulin book both list the outer part of the 2nd deck as having 5 3/4" class B. Wonder where that figure came from for multiple books to list that. The South Dakota class also has slightly thicker second deck on the outboard part. I just find it odd that the general plans doesn't show this alleged difference. Also, the general plans don't seem to show the thickness of the Class A and Class B belt either.

    Also, the New Jersey plans below label Stakes M and N as 60 lb STS. These look official to me.

    http://maritime.org/doc/plans/bb62.pdf
    The Booklet of General Plans do not show the thickness of strakes M & N because THEY ARE NOT SUPPOSED TO.

    On the internet you will find a nice color drawing of a modernized Iowa. The only above deck armor they mention is for the Tomahawk Armored Box Launchers. Since the word "armor" is in the title, they wanted to know what kind. So they asked Friedman what it was.

    Remember, the drawing I state above is all done in Polish and Poland was an Eastern European communist country at time. Therefore, Poland was not on the "Need to Know" list. Do you think Friedman would have given them a "correct" answer?

    Remember: LOOSE LIPS SINK SHIPS. Just as true today as it was in WW II.
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  7. #22
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    The link to the plans of the New Jersey I gave lists Stakes M and N as 60 lbs STS, which corresponds to 1.5". Are you saying that STS plate lbs number to thickness conversion is classified?

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    Quote Originally Posted by RustyBattleship View Post
    But the 4 3/4" thick Class B armor on top only runs between the Port & Stbd Holding Bhds 4. AND, it is NOT welded (sort of). It is secured to the 3rd deck by "Quilting Pins". These are a version of a "Cold" rivet. It's hard to describe by words only as it is a unique design and when I first reviewed the plans as to how they are made and installed gave me much more respect for the engineers that designed them and shipfitters who installed them back in those early post-depression times.

    But, in a nutshell, it was determined that Class B armor was not a necessary weight to add on as the past the P&S Holding bulkhead. But it is interesting (though logical) that holding bhd 4 is only 1/4" thick M.S. between Main and 2nd Decks. But below 2nd deck it is 5/8" thick STS.
    The plans seem to show that there is armor on second deck between torpedo bulkhead 3 and holding bulkhead 4, though the thickness doesn't seem to be labelled differently in the plans, and other book sources claims it's a bit thicker.
    Last edited by Radical; 24 Aug 16, at 04:56.

  8. #23
    Defense Professional RustyBattleship's Avatar
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    Don'f forget, the four Iowa class Battleships were built in two different shipyards. New York NSY (aka Brooklyn Yard) built the Iowa and Missouri. Philadelphia built the New Jersey and Wisconsin. Sometimes the booklets of the varied shipyards had some alterations made for some reason or the other. But the fact is, once it was known that strakes M & N were 1 1/2" thick STS (yield strength of 110 KPSI) it didn't make much difference as their ultimate purpose was Tokyo Harbor (though Iowa was put on "Tirpitz Watch" at New Foundland should a refueling tanker be spotted going up the Norwegian coast).

    Actually, identifying 1.5" thick steel as 60 lb plate was just a simplification. It actually weighs 61.2 lbs per square foot. We didn't use degreed engineers actually cutting, fitting and welding those plates. Engineers used the EXACT weights when calculating bouyancy, etc. Most of the shop people didn't waste time with decimal points (I was one for the first 10 years at LBNSY). If the layout section needed a 6 foot wide by 20 foot long plate of STS to pull out of the rack and set down on a layout table to scribe the template for cutting and center punching centers of rivet holes, we didn't waste time with decimal points. The only time the layout section considered the actual thickness and type of steel was when they had to look up on the wall for a chart to show what the tangents of a bend radius should be if the plate had to have a curved end to it. A little tricky because you had to consider the NEUTRAL radius of the bend. The inside of the bend shrinks while the outside stretches. So your tangency lines (marked at each end with a diamond symbol with a black felt point pen) would be spaced correctly for the flanging brakes to literally bump that curve into shape several times.

    I did that kind of work from 1954 to 1964 before transfering into the Design Section. Even then, I had to calculate the EXACT size of the plate for weight and moment data so our Scientific section could then calculate its center of gravity for ballasting.

    Naval Architecture isn't just designing a pretty looking boat. With Warships, you not only have to make sure it stays the right side up but that it can go through a Typhoon, slug it out with some shore batteries and go back out through that same Typhoon again. That's one of the lessons I had to teach young engineers fresh out of college who said we OVER DESIGNED our ships. I would tell them, "Forget about designing radio towers, oil well derricks or anything like that. We are designing WARSHIPS that have to go TO HELL AND BACK." (I reverently thank Audie Murphy for that title because it is true of EVERY Soldier, Sailor, Marine, Coast Guardsman or Airplane crewman who has to do that).
    Able to leap tall tales in a single groan.

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    What is the thickness of Backing Bulkhead 3? This is the backing bulkhead for the Class A belt, and the plans don't seem to label the thickness. Various sources list it as 7/8 inch thick STS.

  10. #25
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    Quote Originally Posted by Radical View Post
    What is the thickness of Backing Bulkhead 3? This is the backing bulkhead for the Class A belt, and the plans don't seem to label the thickness. Various sources list it as 7/8 inch thick STS.
    Well, it IS STS for sure. But some changes were made along the line when we discovered that the German Bismarck class Battleships and the Japanese Yamato class Battleships ignored the London Treaty limitations of size.

    But here's a wierd thing about rolled steel plate. The thicker it is, the cheaper per pound it is. To get 7/8" thick plate you have to heat and put 1" thick plate through the rollers one more time. All that work costs money. Since Class A armored Bulkheads 50 and 166 were increased in thickness on the Missouri and Wisconsin, I would not be surprised if the backing bulkhead of the main armor belt would be much thicker.

    Of course, how much thicker was never mentioned by any of the shipfitters, welders and riggers after they clocked out for the day.

    Wife: "Hi Hon. You look pooped. What did you have to do today?"
    Husband: "Oh, just the usual, building a Battleship. But speeding things up a bit because Philly wants to launch her on December 7th. For obvious reasons of course."

    Loose Lips Sink Ships.
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  11. #26
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    Quote Originally Posted by RustyBattleship View Post
    And yes, the powder magazines are sectionalized. Very sectionalized. I have redrawn their arrangements with Corel Draw 5 which worked extremely well with Windows XP but with this %$#*@ Windows 7 I can only show them for a few seconds in hopes of typing "print" before Bill Gates stops my Corel from working.
    Hey Rusty, I was reading some past discussions and have a possible solution for your Corel draw problem, I had a similar problem with an old 32 bit windows xp program, when i went to windows 7 64 bit......Frustrated i searched for a solution and fixed it completely by creating a virtual machine on my Win 7 PC

    Virtual machines allow you to run other operating systems within your current operating system – the operating systems will run as if they’re just another program on your computer. Virtual machines are ideal for testing out other operating systems – like the new Windows 8 or alternative Linux operating systems. You can also use virtual machines to run old software on operating systems it wasn’t designed for – for example, you can run Windows xp-32 bit programs on a Windows 10-64 bit with a virtual machine.

    Even I was able to do this fairly easily, (not a Geek) and youll be able to re-install your old XP and corel draw on it
    Website....
    http://www.howtogeek.com/196060/begi...tual-machines/
    Video....
    https://www.youtube.com/watch?v=dzKa8AcdrPE

    Any teenager could probably do it for you....and Im planning to go to California in 2017, will visit the Iowa if I can and would be honored to do it for you if not resolved by then.

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