RE: Witpblazers (Full Version)

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mdiehl -> RE: Witpblazers (5/13/2004 7:58:11 PM)

quote:

I've found this discussion engaging for the most part, but I'll agree it's had some dross. Being so new here, I cannot personally attest that you're a troll as others have said/implied, but I'd say it's always best to avoid ad hominem statements like "you clearly do not know anything" and chest-thumping like "my pov is well-informed," especially as you've posted inaccuracies numerous enough to make me lose count (granted, I can't count all that high). Haughtiness gains nothing and can only cloud over the new information available from others. Barbarrossa knows more about the rangekeeper than I ever will, so I'd be foolish to distance myself from what he has to say. Everyone here can school me on matters of the war games, about which I know nothing. Why would I want to insult people who can teach me?


The others who make such claims are people who argue by anecdote without presenting facts. Something that you yourself have done numerous times. "Nate's data is incorrect." "Dunnigan and Nofi are incorrect." "The Yamato's immune zone is ..."

You talk a wonderful game but have yet to offer an authoritative source that contradicts either Okun's pages or Dunnigan and Nofi, nor have any of the "Yamato would wupass because of her [greater penetration, better armor, alledged superior accuracy] offered any authoritative point by point comparison akin to the one available via combinedfleet.com in re BB design.

What we HAVE established in yours posts, my posts, and third party references is that:
1. Yamato's armor was generally thicker than Iowas.

2. Yamato's armor was of generally inferior grade.

3. Yamato's armor placement seems not to have included decapitation layers outboard of the main armored spaces sufficient to decap a US 16" shell.

4. Iowa had such decap layers and would at many oblique angles decap an IJN Japanese shell.

5. Decapitation is a very important problem because any shell that loses its AP cap is unlikely to penetrate armor of any substance at all.

6. Yamato's underwater protection was flawed rendering her vulnerable to torpedoes. Hard to say about underwater near misses from AP rounds.

7. Iowa's underwater protection was proof against underwater near misses from AP rounds because the armored belt was inclined and continued partly under the hull.

8. The Japanese 18" shell was generally of inferior grade, comparable to shells used by other navies 2.3 decades earlier.

9. Of all the AP shells in the world the US AP shells had the best penetration properties per caliber, both in normal (90 degree) hits and, more importantly, in oblique hits out to 40 degrees.

10. The Japanese 18" shell sacrificed ballistic properties and penetration properties in order to maximize it's near-miss underwater performance --- against an Iowa these shells could not have penetrated the main belt in a below water hit. So the arena for which Japanese 18" performance was optimized was an arena in which it could not have done substantial damage to an Iowa. Caveat of course that almost any ship is vulnerable to a rudder or shaft hit.

11. Claims that the Yamato out-ranged the Iowa are based solely on the ballistic maximum range of the guns. When observation is taken into account the Iowa had 8000 yards on the Yamato, in all of which even YOU seem to admit Yamato was vulnerable to plunging fire.

12. Yamato suffered a secondary magazine hit from a 1000 pound bomb that pentrated through her main armored deck. Something that you seem to regard as impossible. That fire, which Japanese survivors stipulate was uncontrollable and caused the magazine walls to heat (last observed to be glowing red), put the 18" main magazine at risk. We can agree that Yamato sank first as a result of torpedo damage. We can also agree that shortly after sinking, Yamato exploded. This explosion could ONLY have occurred as a result of a fire. While one cannot ultimately know exactly why the explosion occurred, every account of Yamato's demise assign probable cause of the explosion to uncontrolled fires that began in Yamato's secondary armament magazines.

13. We know that Iowa had armored protection and isolation between magazines withing the citidel that dramatically lessened the likelihood of such an event.

Now, you have claimed, without substantiation, that significant portions of Yamato's armor were immune to US 16" penetration in a significant range of potential engagement. Your so-called "immune zone." On what is that claim based? Is the author an authoritative source that has considered in detail the armor thickness, the armor design and quality, and the US 16" AP shell design and post-war ballistics tests?

Given the inferior penetration properties of Yamato's 18" AP shells and the multiple decap layers including external decap layers and STS plates outside of the main armor belt, and multiple STS armor decks above the main deck armor, what makes you think a Japanese 18" round will retain its cap, its fuse and bursting charge intact when striking an Iowa at anything much deviated from the normal (vertical)?

(Footnote: I take it that your alleged "immune" zone comes from: 1. the assumption that Yamato's 9.1" deck armor was the equivalent of US face-hardened and therefore likely to stop a USN 16"L50 at ranges of 30,000-23,000 yards, at which ranges the US 16" Mark 8 Mod 6 shell used in the Iowas had a pentration that varies from 6-8" at a 35 degree oblique angle. 2. The assumption that Yamato's belt armor and side armor would not be struck in those ranges. 3. The assumption that no near misses would occur that could compromise Yamato owing to her poorly placed belt armor and its apparent inability to resist waterline hits. 4. That we must ignore the 1000 pound AP bomb hit on Yamato or assume that such a bomb has penetration that exceeds 9." I do not know what the penetration of the US 1000 pound is supposed to have been.)

(Second footnote. Assuming that such an immune zone exists within any portion of the engagement range it is smaller when facing a SoDak because of differences in the 16"L45 and 16"L50 trajectories.)



mogami -> RE: Witpblazers (5/13/2004 8:11:20 PM)

Hi, The penetration of any air dropped bomb is dependant mostly on the altitude the bomb is dropped from. (why I get sick of attacks at 1000 feet.) Pilots did not drop bombs from higher altitudes because they were worried about flak. They attacked at the those altitudes because that was the height the bombs needed to gain the required energy to penetrate.



mdiehl -> RE: Witpblazers (5/13/2004 8:49:36 PM)

According to Chuck Hawks' web site, which cites Conway's and Junusz Skulski's The BB Yamato, the Yamato class were allegedly thought, by the Japanese, to have deck armor that was proof against a 2,000 pound AP bomb dropped from 15,000 feet. Given multiple 1000 lb AP bomb hits that started fires that set off Main 1 (forward) and set a fire between Secondary aft and Main Aft upper magazines that also would inevitably have destroyed her, there is something overall amiss in the historical demise of Yamato.

It has to be either that her deck armor was substantially flawed as to quality, permitting bombs half the weight of the ones the armor was supposed to stop, to penetrate the citidel, or else the upper magazines were outside the main deck armor and yet not sufficiently isolated from the main below-armor-deck magazines. Otherwise there is no explaining two critical bomb hits from 1000lb AP bombs. Yamato seems as vulnerable to chain reaction explosions as HMS Hood.

Interesting and perhaps relevant are the near misses inflicted on Yamato in late 1944. A 1000 lb AP bomb exploded close abroad Yamato, tearing off a hull plate forward and compromising her watertight integrity to the tune of 3000 tons of water shipped in. I doubt the blast would have penetrated her armor belt, but in all this conversation about the effects of near misses, this minor anecdote is marginally entertaining. (Caveat: the same sorts of things could of course happen to Iowa. Yamato had much more floodable space outside of her protected area. Does this mean anything important? Hard to tell.)

Most of the outcome of an Iowa vs Yamato battle seems to me to rest on which ship scores the most hits at range the fastest. Near misses will flood spaces outside of the armor belt and non-penetrating hits will damage secondaries and fire control. Iowa is more likely to get such hits sooner than Yamato. So assuming that Yamato has any immune zone with respect to armor, she's likely to be hors d' combat anyhow owing to inability to shoot and to reduced speed from flooding.

The decapping horizontal plate I mentioned earlier was the STS-faced hardened bomb deck designed to both activate the fuse on an incoming shell and strip the cap off the shell. How effective it would have been is anyone's guess. But Yamato did not have an STS-quality decap layer above her main deck armor.

Vis a vis the posts that preceded all this, positing 5 USN BBs with superior gunnery against 2 Japanese superheavies, and a bevy of third-rate BBs, the Japanese TF will lose probably because the early damage will weigh more heavily against IJN secondary systems than against USN secondary systems. The US TF would then have time to sink the worst-damaged Japanese BBs while remaining relatively unscathed from retyrn fire.



Brady -> RE: Witpblazers (5/13/2004 8:53:35 PM)

"Hi, The penetration of any air dropped bomb is dependant mostly on the altitude the bomb is dropped from. (why I get sick of attacks at 1000 feet.) Pilots did not drop bombs from higher altitudes because they were worried about flak. They attacked at the those altitudes because that was the height the bombs needed to gain the required energy to penetrate. "

Back when I was skydiving (and in my various physics classes) we learned that a falling object will never excead what they called terminial velocity, wind resistance would effect this and depended on the object in question, but generaly speaking as long as their was suficient height for the object to acheave terminial velocity, it would not go any faster, unless of course it was propeled by some force.



mogami -> RE: Witpblazers (5/13/2004 8:59:34 PM)

The terminal velocity of a falling body occurs during free fall when a falling body experiences zero acceleration. This is because of the retarding force known as air resistance. Air resistance exists because air molecules collide into a falling body creating an upward force opposite gravity. This upward force will eventually balance the falling body's weight. It will continue to fall at constant velocity known as the terminal velocity.

The magnitude of terminal velocity depends on the weight of the falling body. For a heavy object, the terminal velocity is generally greater than a light object. This is because air resistance is proportional to the falling body's velocity squared. For an object to experience terminal velocity, air resistance must balance weight. An example that shows this phenomenon was the classic illustration of a rock and a feather being dropped simultaneously. In a vacuum with zero air resistance, these two objects will experience the same acceleration. But on the earth this is not true. Air resistance will equal weight more quickly for the feather than it would for the rock. Thus the rock would accelerate longer and experience a terminal velocity greater than the feather.

Another factor that affects terminal velocity is the orientation at which a body falls. If an object falls with a larger surface area perpendicular to the direction of motion it will experience a greater force and a smaller terminal velocity. On the other hand, if the object fell with a smaller surface area perpendicular to the direction of motion, it will experience a smaller force and a greater terminal velocity.

The terminal velocity for a skydiver was found to be in a range from 53 m/s to 76 m/s. Four out of five sources stated a value between 53 m/s and 56 m/s. Principles of Physics stated a value of 76 m/s. This value differed significantly from the others. Then again, the value is variable since the weight and the orientation of the falling body play significant roles in determining terminal velocity.



Brady -> RE: Witpblazers (5/13/2004 9:37:18 PM)

TY for posting that Mogami, it has been some time since I paid close atention to such things what I remembered other than what I mentioned above, was that at a given point you would simply not fall any faster (terminial velocity), what was not entirely clear to me was Just how it took for this to hapen, for some reasion 33ft. per second per second comes to mind but I cant remember the exact context, and I was unclear if what I rememberd from skydiving was a general referance for all objects or just us skydivers, I do know the feather and the rock comparasion this I remembered fro physics, but how all this aplied to the present debate was not entirely clear to me. What Ifelt was the case is this:

A bomb droped from leval flight dident realy nead to be all that high, just high enough to reach it's terminial velocity, which based on my experances skydiving and in class, didnet nead be all that high, a couple thousand feat would seam to be more than suficcient.

This is whear my understanding neads some help, one would asume that difenernt weight bombs would vary in the height that they neaded to be droped to acheave this effect, and that dive bombing would lessen the height neaded to acheave this effect as well.



barbarrossa -> RE: Witpblazers (5/13/2004 9:39:15 PM)

Initial velocity of an outgoing HE round at reduced charge was somewhere in the range of 2300 fps to 2600 fps. if memory serves. (this is from the doppler radar installed atop the turrets during the last commisioning)

The HE round was around 1800 lbs. AP 2700 lbs.

IV would be substantially higher for a full powder charge. We never fired full charge because of the excessive bore wear that it caused

We never fired an AP round while I was aboard Whisky. Drats.



mogami -> RE: Witpblazers (5/13/2004 9:39:49 PM)

Hi, 33 feet per second per second is the rate of acceleration

In the first second of fall the object moves 33 feet in the next it falls 66 feet in the next 99 it keeps going till TV is reached.



Damien Thorn -> RE: Witpblazers (5/13/2004 10:01:03 PM)

quote:

ORIGINAL: Mogami

Hi, 33 feet per second per second is the rate of acceleration

In the first second of fall the object moves 33 feet in the next it falls 66 feet in the next 99 it keeps going till TV is reached.


Actually, won't it fall only 16 feet the first second? 1/2 a t^2.



rhohltjr -> Wow ! what a thread (5/13/2004 10:19:28 PM)

Not to hijack this thread, cause all this info is just statistic ambrosia for sure.

Now you guys have me wondering about Japanese naval shells (Nagato)fitted
with fins and dropped by level flying Vals or Kates at stationary targets like Arizona.

I suppose the Nagato's 16" shells were able to penetrate the deck armor of
Arizona(at terminal velocity). When did the STS armor shell decapping technology
come about?

And, Japanese shell technology went backward with the 18.1"? I can't remember where
I heard or read this info about a modern artillery shell called a 'Copperhead', but this shell
is supposed to have some unbelievable penetration ability. Enough to smite either of the
big ships this thread has been about. Is this true? I know one of you guys knows about this.
Has our shell technology really advanced that far. OR is this just a huge urban legend I am
repeating?

What a thread! - to all involved.[&o]



Mr.Frag -> RE: Witpblazers (5/13/2004 10:21:58 PM)

quote:

Actually, won't it fall only 16 feet the first second? 1/2 a t^2.


Actually, NO! [:D]

Don't forget the bomb is also travelling forward that the speed of the releasing platform. [;)]



Damien Thorn -> RE: Witpblazers (5/13/2004 10:53:37 PM)

quote:

ORIGINAL: Mr.Frag

quote:

Actually, won't it fall only 16 feet the first second? 1/2 a t^2.


Actually, NO! [:D]

Don't forget the bomb is also travelling forward that the speed of the releasing platform. [;)]


Oh, were we still talking about bombs? I thought this was the physics forum. Sorry. [;)]



mdiehl -> RE: Witpblazers (5/13/2004 10:57:47 PM)

Rholtjr -

For a lengthy discussion of armor properties see: http://www.combinedfleet.com/metalprp2002.htm

The immediate answer to your question is that US STS (special treatment faced hardened) steel was introduced in 1910. A substantial increase in its use in USN warship construction occurred in ships built after 1930. I do not know for sure, but if Arizona's upper decks were armored at all, it almost certainly did not have STS face-hardened steel. Okun uses the phrase "lavishly used" in US post-1930 construction and notes that the US was unique in the 'lavish' use of face-hardened armor in internal compartmentalization (bulkheads).

I may have found out, also, why those 1000 pound AP bombs penetrated Yamato.

quote:

JAPANESE MOLYBDENUM NON-CEMENTED (MNC) ARMOR
NOTE: Not to be confused with U.S. pre-WWI MIDVALE NON-CEMENTED face-hardened armor (see below))
USAGE: Used exclusively for the main deck armor of the WWII IJN YAMATO Class battleships.

COUNTRY COMPANY TIME FRAME TENSILE YIELD Y/T % EL % RA BRINELL
JAPAN ALL 1941-1945 100-120 76-96 .76-.80 23 58 210-235

Replaced NVNC (see above) only in this single purpose; NVNC was used everywhere else that had heavy homogeneous armor in the IJN YAMATO Class. Only slightly better than NVNC, it is not obvious whether this armor, which used 0.3-0.42% Molybdenum and a more conventional 0.35-0.42% Carbon, was a copy of British World War II NCA or German Krupp Wh (see above) armors--one source says that it was based on German armor--or a completely original Japanese product. Production plates were mostly in the thickness range of 7.87-9.06" (20-23cm), though a huge 14.96" (38 cm) thick MNC grating plate with many cylindrical holes was placed over the openings of the funnel uptakes in the armored deck to keep out projectiles; from U.S. tests, this plate would only be about 40% as resistant as a solid plate, so the effective thickness of it is only about 6" (15.2cm) of solid MNC armor..


I do not know how many draft uptakes Yamato had. One of the US 1000 pound AP bomb hits struck just aft of the mainmast causing a fire foreward and may have struck on this plate. It would explain (to me anyhow) why Yamato's underwater explosion is attributed to the detonation of Main 1 (forward) rather than the aft main magazine via a chain explosion from the aft secondary initiated by the uncontrollable fire there.

This is actually a very interesting site because there is also a discussion of the Japanese discovery, in 1943, of interior brittleness in Yamato's >11" vertical armor (Japanese Vickers Hardened Non-Cemented Face Hardened (VH)) that would have caused the plates to fracture compleletely at the point of impact of a heavy caliber shell or bomb, leading to secondary effects such as turret jams.

The same web site also includes information about post-war tests at the Dahlgren yard that demonstrated that the US 16"L50 and 16"L45 had greater penetration than the Yamato's 18.1" guns. At close range, the 16.1 could penetrate the turret face of a Yamato. At no range could the Yamato penetrate the turret face of a Yamato (moot, of course, except that it indicates that the penetration of the 16" Mark 8 mod 6 was better).



Dunedain -> RE: Witpblazers (5/13/2004 11:23:07 PM)

Mogami: You raise a very good point. Do AP bombs in WitP suffer a realistic penetration penalty if they are
dropped from below the minimum necessary height for them to be fully effective?

I certainly hope so.



Tiornu -> RE: Witpblazers (5/13/2004 11:37:15 PM)

Because of the extreme power of the super-heavy shell, the new American battleships have a chance to win against any opponent, even Yamato. Their unsurpassed FC adds to this factor. Compared to Iowa, the older designs suffer slightly; the inner edge of Yamato's IZ is a bit closer since, though Iowa can fire at SoDak's low velocity, SoDak cannot fire at Iowa's high velocity.
Except for certain details, SoDak's armor is similar to Iowa's. Washington lags behind, and I doubt she has any IZ at all against 46cm shells. If you want real specifics, you'd have to run the FACEHARD calculations, which is something I religiously avoid due to my the cold sweats I get when dealing with numbers..



Svar -> RE: Witpblazers (5/14/2004 12:21:16 AM)

I don't post very often but thought I would share this.

Terminal velocity is when a body’s weight equals its drag. Drag is defined as D = Cd1/2rV2S, where Cd is the drag coefficient (dependent on the falling body’s shape), r is air density (weak function of altitude i.e. at 5k 86.2% of sea level and at 10k 73.9% of sea level), V is the body velocity, and S is the frontal area of the falling body. A falling body will accelerate at the force of gravity, about 32.2 ft/sec2. Drag will act on both the vertical and horizontal components of the body velocity. Hence the horizontal velocity will decay because of the horizontal drag component and vertical velocity will accelerate at 32.2 ft/sec2 minus the vertical component of drag at any moment in time. Dropped from a high enough altitude the horizontal velocity will decay to almost zero while the vertical velocity will stabilize at the terminal velocity when the body drag equals the body weight.

Unfortunately the subscripts and superscripts don't paste from MSWord. The d in Cd is a subscript, the r for air density is really the Greek letter roe, the 2 in V2 is a superscript, and the 2 in sec2 is also a superscript.



mdiehl -> RE: Witpblazers (5/14/2004 12:23:37 AM)

Iowa was likely to win against any Axis vessel, although Yamato may have had a chance to defeat Iowa. We've established that the 16" has better penetration at close range and sufficient penetration at long range to do for Yamato, and that Yamato's belt, deck, and vertical armor each had peculiar (to their manufacture or construction) flaws that rendered her vulnerable at all ranges -- the vertical armor cracking problem, the weak armored protection around her boiler and funnel intakes, the improper design of her belt armor, and the absence of hardened steel armored bulkheads within critical spaces in the citidel and between her upper magazines).

The questions remain:

Did Yamato have a face hardened upper deck that might decapitate a US 16" shell in the mid ranges? And was Yamato's 18" shell likely to be decapitated by Iowa's STS-steel bomb deck in those same ranges? If the answer to the first is no or the answer to the second is yes, then there is no "immune zone" for Yamato that Iowa does not also share (notwithstanding Yamato's cracked turrets, penetrated belt armor, and penetrated intake grating).



Brady -> RE: Witpblazers (5/14/2004 12:38:10 AM)

Tiornu, thanks again for the assesment.

....................................

Svar, TY for the detail their it helped to bring back or rather refress the details of my past studies of the subject.

It would seam reasionable to asume that an object shaped like a Bomb and designed to travel through the air would be able to acheave it's terminial veloicty fairly quickely, thus High Alt is not realy going to nexcessarly improve the penatration effect, as long as the height is suficient enough to alow the bomb to acheave terminial velocity, it is High enough.
Dive Bombing could alow for a lower drop alt since the dive velocity would of course lower the alt nescessary to acheave the terminial effect.

This begs the question:

How how did you nead to be to get the terminial effct with a 500KG AP Bomb?



Hornblower -> RE: Witpblazers (5/14/2004 12:48:02 AM)

Mdiehl makes a very valid point, in my opinion. Its not just the size of the shell, or the thickness of the armor, but the ability to put the shell on target. In this respect the Mk 8 fire control gave – again in my opinion – an advantage to the Iowa’s. In all my reading of the action off Samar Island in ’44, I don’t recall any mention of the Yamato scoring any hits with her main battery on any ship in Taffy 3.. in 1hr and 15 min of firing (before she turned away to avoid the Hermmans torp’s) she was unable to score a single hit on any of 6 CVE’s moving at the breakneck speed of 17.5 knots. Actually, during the entire action she fired 108 salvo’s at ranges from 27,000 down and not one hit. Granted dodging torp’s, planes, and the rain squall didn’t help, but the effects of these- in a distraction sense – can’t be far removed from getting hit with a 2700 pound shell or shells.



Tiornu -> RE: Witpblazers (5/14/2004 12:55:07 AM)

I never made any such statement about "Nate." I don't know anyone named "Nate." If you're referring to Nathan Okun, I have offered authoritative correction of his earlier work; it comes in the form of his later work. The latest FACEHARD version is available for downloading by anyone for free. All his recent papers are posted at warships1, and I already gave the URL for the extensive tables based on his armor penetration formulae.
There is no authoritative point-by-point comparison of battleships. If you've mistaken the "baddest" competition for such a comparison, that's unfortunate. It's a fun exercise and a good starting-point for discussion, but it's not what you want it to be.
quote:

2. Yamato's armor was of generally inferior grade.

Yes, except for where it was roughly equal or superior.
quote:

3. Yamato's armor placement seems not to have included decapitation layers outboard of the main armored spaces sufficient to decap a US 16" shell.

On the other hand, Iowa did have a decapping surface sufficient to decap a US 16in shell. Why this would be needed, I cannot say. Unfortunately, it could not decap an 18.1in shell at any useful angle. You haven't mentioned that it's almost impossible for Iowa to hit Yamato's deck with a shell that still has its cap, while any 18.1in shell passing just above Iowa's belt will probably keep its cap.
quote:

4. Iowa had such decap layers and would at many oblique angles decap an IJN Japanese shell.

The only shells to be decapped by Iowa's waterline plating are those already striking at such obliquity that they would shatter even with their caps in place.
quote:

7. Iowa's underwater protection was proof against underwater near misses from AP rounds because the armored belt was inclined and continued partly under the hull.

Iowa certainly wasn't proof against near-misses from Japanese diving shells.
quote:

8. The Japanese 18" shell was generally of inferior grade, comparable to shells used by other navies 2.3 decades earlier.

Japanese shells were designed for a different function. Ignoring that for the moment, if the British had had shells proofed to 30deg (as Yamato's were) at Jutland, the battle would be remembered as a British tactical victory.
quote:

9. Of all the AP shells in the world the US AP shells had the best penetration properties per caliber, both in normal (90 degree) hits and, more importantly, in oblique hits out to 40 degrees.

American shells had superb performance in high-obliquity impacts. Nearer the normal, they were nothing special. Anyone who's read Campbell's Naval Weapons of World War Two knows about that. Compare the belt penetration for the US 16in/45 with that of the British 14in/45.
quote:

10. The Japanese 18" shell sacrificed ballistic properties and penetration properties in order to maximize its near-miss underwater performance --- against an Iowa these shells could not have penetrated the main belt in a below water hit. So the arena for which Japanese 18" performance was optimized was an arena in which it could not have done substantial damage to an Iowa. Caveat of course that almost any ship is vulnerable to a rudder or shaft hit.

Yamato's shells probably would not have penetrated Iowa's main belt below the waterline because they would probably not have hit the main belt below the waterline. More likely, they would have hit the tapered Class B armor below the main belt.
quote:

11. Claims that the Yamato out-ranged the Iowa are based solely on the ballistic maximum range of the guns. When observation is taken into account the Iowa had 8000 yards on the Yamato, in all of which even YOU seem to admit Yamato was vulnerable to plunging fire.

Yamato's range advantage probably is inconsequential. If circumstances dictated that radar wasn't given accurate readings but optics were applicable, Yamato's greater baselength would give her the advantage. I wouldn't count on many hits under those circumstances, however....
quote:

12. Yamato suffered a secondary magazine hit from a 1000 pound bomb that pentrated through her main armored deck.

That is a fundamentally flawed description of what happened. The bomb did not penetrate the armor deck because it never hit the armor deck.
quote:

This explosion could ONLY have occurred as a result of a fire.

Well, the USN disagrees with you. The NTM analysis claims only that fire was a probably cause of the explosion, and their conclusion seems to have been that the aft 46cm magazines blew, not a forward one.
quote:

13. We know that Iowa had armored protection and isolation between magazines withing the citidel that dramatically lessened the likelihood of such an event.

No, we don't know that. What isolation was there between Iowa's magazines?
quote:

Now, you have claimed, without substantiation, that significant portions of Yamato's armor were immune to US 16" penetration in a significant range of potential engagement.

How come when you cite derivatives of Nathan's work, it's "authoritative," but when I give you Nathan's calculations it's "without substantiation"?
quote:

Given the inferior penetration properties of Yamato's 18" AP shells and the multiple decap layers including external decap layers and STS plates outside of the main armor belt, and multiple STS armor decks above the main deck armor, what makes you think a Japanese 18" round will retain its cap, its fuse and bursting charge intact when striking an Iowa at anything much deviated from the normal (vertical)?

I guess I can point out again the Iowa does not have decapping layers outside her belts. I can also point out that Japanese shells had such good penetrative qualities against homogenous armor that they are off the scale for Nathan Okun's M79APCLC program. I'll also repeat that Iowa's shells would have more difficulty hitting the armor deck with cap in place than Yamato's.
quote:

(Footnote: I take it that your alleged "immune" zone comes from....

You have taken a platoon of wrong things. But you now have the ability calculate Yamato's IZ for yourself. Enjoy.
quote:

1. the assumption that Yamato's 9.1" deck armor was the equivalent of US face-hardened and therefore likely to stop a USN 16"L50 at ranges of 30,000-23,000 yards, at which ranges the US 16" Mark 8 Mod 6 shell used in the Iowas had a pentration that varies from 6-8" at a 35 degree oblique angle.

I don't know why you're mixing up face-hardened and homogenous armor. Perhaps that's because you don't know where each ship had each type. It is not hard to find good sources on Yamato's armor composition; the NTM is a good place to start.
quote:

2. The assumption that Yamato's belt armor and side armor would not be struck in those ranges.

The rule of thumb is that 20,000 yards is the 50/50 dividing line for belt/deck hits--or something like that. I never paid much attention to that, and the belt inclination changes everything anyway.
quote:

3. The assumption that no near misses would occur that could compromise Yamato owing to her poorly placed belt armor and its apparent inability to resist waterline hits.

Yamato's belt armor is better-placed than Iowas. Its inability to withstand shell hits is not apparent to anyone I know of.
quote:

4. That we must ignore the 1000 pound AP bomb hit on Yamato or assume that such a bomb has penetration that exceeds 9." I do not know what the penetration of the US 1000 pound is supposed to have been.)

It's discouraging to see that you think the 9in deck armor has something to do with the bomb hit you're discussing. Do you have any information on Yamato's deck armor? Other good sources include Skulski and G&D. USN figures say the 1008-lb Mk 33 bomb could defeat 5.8in Class B armor; 5in when dropped from 10,000ft or from 6500ft in a 300-knot 60deg dive. I decline to get sucked into the terminal-velocity tangent!



barbarrossa -> RE: Witpblazers (5/14/2004 12:57:21 AM)

quote:

ORIGINAL: Hornblower

Mdiehl makes a very valid point, in my opinion. Its not just the size of the shell, or the thickness of the armor, but the ability to put the shell on target. In this respect the Mk 8 fire control gave – again in my opinion – an advantage to the Iowa’s. In all my reading of the action off Samar Island in ’44, I don’t recall any mention of the Yamato scoring any hits with her main battery on any ship in Taffy 3.. in 1hr and 15 min of firing (before she turned away to avoid the Hermmans torp’s) she was unable to score a single hit on any of 6 CVE’s moving at the breakneck speed of 17.5 knots. Actually, during the entire action she fired 108 salvo’s at ranges from 27,000 down and not one hit. Granted dodging torp’s, planes, and the rain squall didn’t help, but the effects of these- in a distraction sense – can’t be far removed from getting hit with a 2700 pound shell or shells.


I was wondering when someone would bring this engagement up[;)]



Dunedain -> RE: Witpblazers (5/14/2004 12:58:58 AM)

Brady: That is indeed what we need to know, and then an appropriate penalty be applied for heights below that.

The height needed for full effectiveness of 500lb., 1000lb., 1500lb. and 2000lb., etc. AP bomb (if the bomb weight
is not quite at those numbers, just group it with the nearest weight category) weights needs to be known.
It doesn't have to be an exact number, but at least close.

Then just subtract a percentage off penetration for every altitude increment below the height required for
full effectiveness. Height penalties could be broken down for every, say, 500 feet below the minimum full effectiveness
altitude for that weight bomb. Just a simple penetration penalty table that's looked up if the bomb is dropped
from an inadequate height. This is then applied to see if the bomb penetrates the armor or is turned by it.

This will make sure that bomb runs from silly low altitudes are as ineffective as they should be. :)



Hornblower -> RE: Witpblazers (5/14/2004 1:07:19 AM)

Had to wait till i got home from work [:D]



Tiornu -> RE: Witpblazers (5/14/2004 1:08:37 AM)

It's correct that Yamato in her first (and only) surface engagement managed no main-battery hits. Hornblower, where did you find the figure of 108 salvoes fired? Do you have a figure for the number of shells?
In her first surface engagement, Iowa scored no main-battery hits. She fired a total of 13 salvoes, 86 shells. Her initial target was a cruiser lying dead in the water at a range of 14,250 yards.



Brady -> RE: Witpblazers (5/14/2004 1:25:13 AM)

"USN figures say the 1008-lb Mk 33 bomb could defeat 5.8in Class B armor; 5in when dropped from 10,000ft or from 6500ft in a 300-knot 60deg dive. I decline to get sucked into the terminal-velocity tangent! "

Thanks for the figures again[:)]

.........................................

Dunedain, I asked this question some time ago and never realy got any kind of answer, but I asumed that since Dive bomber crews were trained in the optimal usage of their planes and the bombs they carried such a rule would be well pointless since they were droped at the "Optimal" height.
Howeaver for Leval bombers this would make some since. I wounder though is 10K realy the nesceaary height to acheave the optimal penatration , or is simply listed as a referance and one established do to that height being desired since it provided some releaf from flack/ack?
Sounds like someone neads to do the math[:)]



Rendova -> RE: Witpblazers (5/14/2004 1:30:11 AM)

One little note that doesn't really answer the question but I still think is Relevant.....

Yamato is home to some fish and Iowa is sitting off the Coast of San Fransico....

So I think its safe to say Iowa would win today, even with one turret tied ber her back [:D]



Mr.Frag -> RE: Witpblazers (5/14/2004 1:34:05 AM)

quote:

ORIGINAL: Rendova

One little note that doesn't really answer the question but I still think is Relevant.....

Yamato is home to some fish and Iowa is sitting off the Coast of San Fransico....

So I think its safe to say Iowa would win today, even with one turret tied ber her back [:D]


I'll debate that point [;)] It is really hard to sink a coral reef [:D]



Greyshaft -> Beware the Wombat!!! (5/14/2004 1:43:26 AM)

quote:

ORIGINAL: barbarrossa
Obviously, the PT skippers were experienced at hunting Wombats back home in Beggar's Canyon.[:'(]


uh... I think that's "Womp Rats"...

Send four and sixpence... we're going to a Dance! [:D]



mdiehl -> RE: Witpblazers (5/14/2004 2:17:22 AM)

quote:

There is no authoritative point-by-point comparison of battleships. If you've mistaken the "baddest" competition for such a comparison, that's unfortunate. It's a fun exercise and a good starting-point for discussion, but it's not what you want it to be.


I'm not sure what you mean by that. By "it's not what you want it to be" you make pretense that you are any more of an authority in judging the merits of that discussion ('baddest') than I. I freely admit that I am not a naval engineer. Are you? Thought not. The fact remains that there is no other comprehensive point-by-point comparson (other than that which we are attempting here). To the credit of that other discussion, it uses real data rather than simply claiming, for example, that an "immune zone" exists (sans credible reference) and then "substantiating" said claim by merely repeating it. In short, I believe that discussion, because I can at least track the assumptions and because it is well referenced, over your statements of opinion.

quote:

Yes, except for where it was roughly equal or superior.


Which happened NOWHERE on Yamato unless you have mistaken thickness for quality. The best armor that you could mention in prior discussion was the allegedly impenetrable turret face on the Yamatos. It turns out that after all post-war live fire tests on said armor using surplus IJN 18.1" and USN 16" guns demonstrated that the Iowa COULD penetrate such armor where Yamato COULD NOT. You have deployed no fact to contradict this irrefutable (because it happened) test. You have also apparently chosen to ignore the cracking problem in Japanese vertical armor that the Japanese themselves discovered in 1943 but could not correct in Yamato and Musashi (beacsue, after all, these ships were already complete).

NEED I SAY MORE? The facts prove that any claim or pretense of superior armor quality on Yamato, even on the thickest armor (the turret face) is incorrect.

quote:

On the other hand, Iowa did have a decapping surface sufficient to decap a US 16in shell. Why this would be needed, I cannot say.


I can answer that question. It was a matter of US practice through the 1930's to design armor to defeat the best-penetrating projectile known to US BuOrd at the time, which was the 16" US AP round.

quote:

Unfortunately, it could not decap an 18.1in shell at any useful angle.


That is an unsubstantiated claim. Do you have a reference that proves that the decap shell over the armor belt could not protect the Iowa from any potentially damaging belt-armor hit? Reference please?

quote:

You haven't mentioned that it's almost impossible for Iowa to hit Yamato's deck with a shell that still has its cap


I do not need to mention that because it is not, as far as I know, correct. Do you have information that indicates the existence of a face hardened upper deck that might, conceivable, decap the best designe AP projectiles in the world? Reference please.

quote:

while any 18.1in shell passing just above Iowa's belt will probably keep its cap.


Again, that is an unsubstantiated claim. Based on a 34 degree oblique angle hit on the STS-hardened bomb-deck on an Iowa it seems very likely that the inferior Japanese 18.1" AP cap would have sheared. But if you have a reference that proves this not to be the case, I'd like to know about it.

quote:

The only shells to be decapped by Iowa's waterline plating are those already striking at such obliquity that they would shatter even with their caps in place.


You mean, 'other than the "diving projectile" design used by the IJN?'

quote:

Iowa certainly wasn't proof against near-misses from Japanese diving shells.


Do you have an authoritative source that substantiates that claim? At what range and what angle of entry onto water?

quote:

Japanese shells were designed for a different function. Ignoring that for the moment, if the British had had shells proofed to 30deg (as Yamato's were) at Jutland, the battle would be remembered as a British tactical victory.


I missed your point on that one. That is, I don't see its relevance. The US projectiles seem to have given good penetration for caliber out to 45 degree angles of obliquity, given the Dahlgren tests of the 14" gun.

quote:

American shells had superb performance in high-obliquity impacts. Nearer the normal, they were nothing special. Anyone who's read Campbell's Naval Weapons of World War Two knows about that. Compare the belt penetration for the US 16in/45 with that of the British 14in/45.


Compare the point blank penetration of the 16"50 and the US 16" wins (it's a higher velocity gun). Compare the 16"L50 to the 18.1" IJN and again the USN wins, as demonstrated by the Dahlgren tests of US 16"L50 and IJN 18.1" guns. Again, only one of those could penetrate the thickest known BB armor (a Yamato turret face) and that was the US 16"L50.

quote:

Yamato's shells probably would not have penetrated Iowa's main belt below the waterline because they would probably not have hit the main belt below the waterline. More likely, they would have hit the tapered Class B armor below the main belt.


I'd like to see a reference that demonstrates that that claim is correct and specifies the likelihood.

quote:

Yamato's range advantage probably is inconsequential.


Let's have a little truth out of your spin. Yamato's theoretical range advantage never existed because of the absence of over-the-horizon shoot capability. The Iowa has an 8000 yard edge on Yamato anywhere other than on a flat earth.

quote:

If circumstances dictated that radar wasn't given accurate readings but optics were applicable, Yamato's greater baselength would give her the advantage. I wouldn't count on many hits under those circumstances, however....


Yeah. And if Iowa was in drydock, or suffering from batteries out of train, or missing a propellor. Whatever. The point is the discussion presumes from the outset that both vessels are operating up to their intended specs. If you want to saddle one side or the other with handicaps that is a different discussion.

quote:

That is a fundamentally flawed description of what happened. The bomb did not penetrate the armor deck because it never hit the armor deck.


You do not know that for a fact. In a subsequent post I pointed out that there were two bomb hits. One aft of the mainmast (that might have hit one of the perforated grates over the boiler intakes or funnel intake, said grates having been demonstrated to provide protection of the equivalent of 6" armor). The other in the spaces between upper main and secondary magazines aft that started an uncontrollable fire that WOULD have destroyed Yamato had she not first sunk as a result of torpedo damage and blown up as a result of a magazine detonation forward. In a nutshell, Yamato was sunk three times in one engagement (and people here seem to think she's still floating somewhere... the irony of it!).

quote:

Well, the USN disagrees with you. The NTM analysis claims only that fire was a probably cause of the explosion, and their conclusion seems to have been that the aft 46cm magazines blew, not a forward one.


What? Your alternative explanation is that a trapped crewmember tipped their cigarette into her gas tank? Yes, NTM has one hypothesis that attributes Yamato's explosion to chain-detonations starting with the uncontrollable fire adjacent to her aft secondary upper magazine (a flaw in compartmentation not shared by Iowa by the way). Strangely, however, the underwater photos of Yamato indicate the greatest blast damage forward. That is why, I suspect, when you read Tulley's TROM and final AAR for Yamato, he attributes the underwater explosion to #1 main (forward) magazine. Yamato was struck all over the place, but one of the earlier strikes was a hit just aft of the mainmast. Given the underwater pix and that hit I've offered (previous post) the suggestion that the early bomb hit penetrated near one of the intake grates and started another uncontrollable fire forward (the AAR, which uses survivor's accounts, stipulates that this struck area was smoking immediately after the hit).

But it's just a hypothesis. Either way, Yamato detonated, either because a hit penetrated her intake grates into a compartment within her citidel and set her uncontrollably on fire, or else Yamato detonated because a bomb hit aft set an uncontrollable fire in her (outside citidel) compartments, detonating her upper secondary, upper main, and lower main aft magazines in a chain reaction (much like the destruction of HMS Hood). Either way, Yamato's design had serious problems.

quote:

No, we don't know that. What isolation was there between Iowa's magazines?


Five inch class B with STS-face hardened plate in every bulkhead within the citidel and between the upper magazines and in the spaces between the turret, uh (I don't know the word for this) column and interior spaces below deck. As the other web-site noted, the US use of that stuff was "lavish." Actually, this strikes me as possibly better protection against splintering from penetrating bursting shells than against fires. But one navy was known for its ability to control fires and the other not.

quote:

I guess I can point out again the Iowa does not have decapping layers outside her belts. I can also point out that Japanese shells had such good penetrative qualities against homogenous armor that they are off the scale for Nathan Okun's M79APCLC program.


The STS-face hardened bomb deck is a potentially decapitating layer. Any Yamato shell striking this obliquely may be decapitated. I have not seen you post a reference that indicates that this layer could NOT decapitate an 18.1" shell. See, on the Iowas, neither the bomb deck nor the main deck were "homogenous armor." Both had STS face hardened armor.

quote:

I'll also repeat that Iowa's shells would have more difficulty hitting the armor deck with cap in place than Yamato's.


You can repeat it but you'll have to cite something that proves same. Why do you imagine that the best face-hardened armor in the world on the Iowa's bomb-deck is going to fail to protect Iowa from the worst-designed (with respect to retaining its CAP) shells used by any navy in WW2. And then you turn around and assert that the best designed shells (with respect to retaining their cap, because they're the ones that are going to retain their cap in an oblique hit) will not penetrate homogenous armor with no evidence of a face-hardened intervening deck?

quote:

You have taken a platoon of wrong things.


And you call me "haughty." You have yet to post any source that contradicts anything I've stated here, you have failed to substantiate any of your claims that you have made about the alleged decap properties of Yamato's belt, and you've chosen to simply ignore the post-war Dahlgren facility penetration tests that demonstrated, without room for debate, that the US 16"L50 had more penetration than the IJN 18/1".

You flatter yourself in comparing your arguments to mine.

quote:

I don't know why you're mixing up face-hardened and homogenous armor. Perhaps that's because you don't know where each ship had each type. It is not hard to find good sources on Yamato's armor composition; the NTM is a good place to start.


I'm not mixing them up. Iowa used face hardened armor on her bomb deck, on the main deck, on the decap surface over her homogenous A belt, and on the interior bulkheads within the citidel. By the way, the Japanese burned all of the design specs and blueprints on Yamato near the end of the war. NTM is "the only place" to start or finish because it is based upon interviews. It's not as reliable information as a real blueprint, but it is the only information available.

quote:

Yamato's belt armor is better-placed than Iowas. Its inability to withstand shell hits is not apparent to anyone I know of.


Again, the weakness in Yamato's upper belt underwater protection is a matter of public record and I have provided links to same and quoted excerpts. There is no evidence that Iowa cannot penetrate Yamato's belt armor at any range where such a hit would occur.

[quoe]It's discouraging to see that you think the 9in deck armor has something to do with the bomb hit you're discussing. Do you have any information on Yamato's deck armor?

Yamato's 9" deck armor was not 9" armor in the area of funnel and boiler intakes. In those areas it was 14" homogeneous with large, cylindrical perforations (they had to be there... air flow), that weakened the 14" perf-plate to the equivalent of 6" of homogeneous armor.

Everything else about the forward bomb hit supposition is only me speculating that a bomb hit from a 1000lb AP bomb might penetrate this perforated plate and explode inside the citidel. A bomb hit in the appropriate general vicinity DID in fact occur (aft of mainmast as mentioned before.. this puts here in the right ballpark to the extent that one can place these hits based on survivors' accounts). Moreover, SINCE Yamato's underwater damage indicates an explosion of #1main (forward) the NTM analysis may well be wrong.

More importantly, any of Yamato's 14" perforated plate armored protection over air intakes (this was the only significant armor protection around intakes that entered the citidel) was penetratable to USN 16"L50 and USN 16"L45 hits at every range that a deck hit was likely to occur.



Mike Scholl -> RE: Witpblazers (5/14/2004 3:29:08 AM)

GENTLEMEN. This is all very interesting..., but what has it got to do with WITP? This
is a strategic level game, and the kind of tactical and balistic arguments you've gotten
into will never come into play in it. The whole issue will boil down to a couple of "random
numbers" generated by the AI to produce a result of "Yamato x hits; Iowa y hits" with
a fairly large variation in possibilities. This "fight" belongs in another forum.



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