Two KGV's vs. Yamato

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Re: Two KGV's vs. Yamato

Post by yellowtail3 »

2 KGV's vs. Yamato (or Musashi)? Well... I've said I'd put my money on the Brit ships, but it wouldn't be a sure thing.

Now, if it were two South Dakotas - shooting shells weighing a thousand pounds more than KGV's 14 inchers? - well, that would be a much safer bet. I don't know that the USN ships would be substantially more damage resistant, but they could probably hit somewhat harder.

I built a model of Musashi as kid; very pretty ship.
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Re: Two KGV's vs. Yamato

Post by lwd »

tnemelckram wrote:As I posted earlier, use the two knot KGV speed advantage to stay out of range until you can maneuver one ship on each of Yamato's hindquarters and then start shooting. Only the three stern guns can bear on you freely while the six up front either can't or are severely impaired. If Yamato turns, run, but maintain contact, and try again. ... .
The problem with this is that Yamato can bring her guns to bear quite quickly with just a fairly minor course change. If she is steaming away from the British ships there is little reason for her not to be "salvo chasing" which will make her harder to hit and likely obscure the fact that she is turning on her foes when she does. If you don't get to close 2 knots gives you a decent chance of disengaging and makes it hard for the other guy to do so. Once you start taking battle damage however all bets are off.
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Re: Two KGV's vs. Yamato

Post by Dave Saxton »

neil hilton wrote:
What you're saying makes sense. The construction steel was hard to weld.
What I'm referring to was the weldabilty of the armour plates, the accounts I've read state that the upper and lower belt armour plates were welded and riveted because the welds were of poor quality. (Yamatos armour was of a new production and I think this is what made them so difficult to weld). ....

Hi Neil,

Just to elaborate a bit more on some of the considerations for welding, and I realize that such munitia isn't common knowlege, but face hardened armour cannot be welded. The Yamato class sloped belt system consisted of the main armoured belt of VH face hardened armour 16.3" thick, and the lower belt extension of NVNC (New type Vickers Non Cemented), non face hardened armour, tapering from 7.8-inches thick to 3.9" thick. (The use of non face hardened armour was to avoid the use of too hard and ridgid of a plate within the overall torpedo defense system.)

According to my drawing there's a intermediate structural piece between the upper belt and the lower belt that contains a keyway joint at the top end of the lower belt.

Most homogenous armour can be welded as long the carbon content is no more than about 0.30%. Generally the carbon content, or what is known as carbon eqivilency (other elements in particular percentages such as nickel, manganese, vanadium...ect... can magnify the effects of carbon or react in certain ways with carbon) is what mainly effects weldabilty. Vanadium content results in difficult welding problems as well.

The new composition MNC deck armour plates could be welded. I'm not sure of the carbon content or possible V content of NVNC?

It was and is common practice to weld homogenous armour plate with austenic stainless steel weld metals, even though the weld metal is significantly less strong than the parent metal. (Although it's ductility and it's resistance to hydrogen embrittlement is exceptional.) For example the USN welded STS with 310 stainless steel and the German Navy welded Wh and Ww with 307 stainless steel.
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Re: Two KGV's vs. Yamato

Post by alecsandros »

Dave Saxton wrote:
The new composition MNC deck armour plates could be welded. I'm not sure of the carbon content or possible V content of NVNC?
About 0.5-0.55% Carbon content in MNVC. No vanadium, from what I can tell... No nickel either... 0.15% copper, instead :D
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Re: Two KGV's vs. Yamato

Post by tnemelckram »

Hi LWD and all!

Thanks LWD for the response to my post, which raises good points. As to the other intervening posts about the armor and construction, I just assume that regardless of the technical details, Yamato has a significant protection advantage.
"The problem with this is that Yamato can bring her guns to bear quite quickly with just a fairly minor course change."
Maybe you underestimate the amount of course change needed to bring the fore guns to bear. Remember the blast damage issues related to the 18 inch guns, in particular regarding the superstructure. Maybe a rather larger (and more time consuming and easier to spot) course change would be needed to give the fore guns sufficient open arcs that avoid severe blast damage. Or maybe the Japanese would learn this the hard way and do a little of the Britishers' warm work on the superstructure for them. This then raises the good point that the British might likewise have to sacrifice use of the rear quad turret for the same reasons.

"If she is steaming away from the British ships there is little reason for her not to be "salvo chasing" which will make her harder to hit and likely obscure the fact that she is turning on her foes when she does."
I don't fully understand what "salvo chasing" and would like to learn more about it from you. In the meantime I'll address what you said with an educated guess.

I assume it doesn't refer to the narrow stern on target presented bearing-wise because on the other hand the target is also longer range-wise. But this may miss some technical aspect of gunnery. I am guessing this actually means taking advantage of the timing between the salvos from two different ships and steering between them, perhaps coupled with the spotting confusion, and/or timing the turn about in conjunction with all of this.

The obscuring of Yamato is a damn good point. It could come from as many as 12 simultaneous splashes, or from smoke from some initial battle damage fires on Yamato in effect creating a "smoke screen" to hide the turn about. In the latter case initial good British shooting could then shortly actually work against them. The best I can propose to counter this is British experience, skill and seamanship. which I think was the best among all the navies in the War, to anticipate this and timely react.

"If you don't get too close 2 knots gives you a decent chance of disengaging and makes it hard for the other guy to do so."
This is the key to my plan. It appears you think that it is on solid ground at least to the extent that the British could probably control where and when the shooting takes place.

"Once you start taking battle damage however all bets are off."
Agreed. The essence of any battle is calculated risk. To paraphrase General Jack Ripper "I ain't saying the British won't get their hair mussed" and we don't even have a study in hand concluding "10-20 million dead, tops, . . . depending on the breaks"! The parts of the British ships most exposed to damage are the forward guns that are the spear point and the bridge and other CCC structures. The propulsion nmad steering in the rear are least exposed. So if the forward hull is still intact, there is still a good chance of being able to chicken out and run away if the battle damage makes the kitchen too hot.
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Re: Two KGV's vs. Yamato

Post by tommy303 »

I don't fully understand what "salvo chasing" and would like to learn more about it from you. In the meantime I'll address what you said with an educated guess.
This is a series of manouvers whereby the ship being shot at alters course towards the spot where the last salvo landed, knowing that the fire control team on the other ship will have spotted that salvo and would have adjusted their aim. By steering towards the last salvo, you essentially are getting out of the way of the corrected one soon to follow.

Another minor point, the Japanese might well choose not to make a run for it and may turn and accept battle, which will complicate things quite a bit. This was just the sort of battle the Yamato class was built for.

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Re: Two KGV's vs. Yamato

Post by Bgile »

tommy303 wrote: Another minor point, the Japanese might well choose not to make a run for it and may turn and accept battle, which will complicate things quite a bit. This was just the sort of battle the Yamato class was built for.
Yes, it wasn't clear to me why Yamato would be running away.
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Re: Two KGV's vs. Yamato

Post by Dave Saxton »

alecsandros wrote: About 0.5-0.55% Carbon content in MNVC. No vanadium, from what I can tell... No nickel either... 0.15% copper, instead :D
Are you talking about the MNC or NVNC? .50-.55% C would make it pretty much non weldable. Cu is actually pretty common in marine metalurgy due to its anti-corrosion properties. The Germans used it in their marine steels. It does have an alloying effect too. I have read some American research on it that confirms that it can greatly increase tensile and yield strength without a detrimental effect on ductility in concentrations of less 0.20%.
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Re: Two KGV's vs. Yamato

Post by alecsandros »

Dave Saxton wrote:
Are you talking about the MNC or NVNC?
NVNC. Sorry for the typo.
Japan faced nickel and chromium shortages in the 1930s and consequently had to replace some of it in the armor plates.
I guess the adition of Cu also makes the plate pretty much unweldable. However, I did not found any reference so far that would indicate this replacement negatively altered the ballistic properties.

From Nathan's papers, I see that the same replacement - Ni with Cu - was made in MNC. In MNC, however, the amount of carbon was about 0.35-0.42%.
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Re: Two KGV's vs. Yamato

Post by tnemelckram »

Hi Tommy and Bgile!

First thanks for the explanation of salvo chasing. Maybe the British could counter the tactic with two ships shooting instead of one with each firing independently instead of following the flag's lead. Different salvo timing and patterns fired from two widely different angles would complicate matters for the salvo chaser because it would have to anticipate two variables instead of one. But I know that there could be confusion on the British ships in spotting fall of shot so they might be constrained by having to firing at least far enough apart in time to tell one from the other. Shots from two distinct angles might be easier to distinguish when they land.
Another minor point, the Japanese might well choose not to make a run for it and may turn and accept battle, which will complicate things quite a bit.
and
Yes, it wasn't clear to me why Yamato would be running away.
Agreed that this complicates things(1) and my reasoning should be made clearer.

In my first Post on this Thread on December 6, 2008 on page 8(2) I posited a tactical situation where Yamato was on a set mission in transit from one place to another which did not contemplate searching for and engaging two enemy BB's - this would be a "meeting engagement". That seems to be a sound tactical assumption for the British Admiral to make because: (a) the ship would be in company with its division mates if it was on a combat mission looking for trouble; (b) historically the ship was reserved for combat in a major fleet engagement which made the Japanese loath to send her out alone on combat missions; (c) she was a fuel hog which the Japanese had a hard time finding fuel for in the first place, let alone enough for the time and range needed to hunt like a cruiser; (d) as a result, she would only be alone when on a more or less straight line mission from one place to another.

By default, all this makes keeping on the general course to her destination the first priority. As a corollary she would resume that course after making tactical turns to engage the British when it becomes clear that their small speed advantage moves them out of range and makes pursuit fruitless. What else can she do except maintain or resume course - stop, sit still and double dog dare them to come closer? Thus Yamato is not running away - she is simply constrained because the mission and circumstances dictate her course.

________________________________
(1) But it's not minor, Tommy! A major driver of my plan is anticipating and addressing this possibility. At the same time this also could be its major weakness because it might frustrate the objective of degrading her fighting ability by getting enough shots and hits on her guns, CCC and other upper works to effectively soft kill her .
(2) I meant to incorporate and carry this over into my current May 8, 2010 Post.
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neil hilton
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Re: Two KGV's vs. Yamato

Post by neil hilton »

Hi Dave,

Thanks for the info about welding, I don't know much about it.
Are you sure that all face hardened armour cannot be welded. Mid and late ww2 tanks all used face hardened armour and were welded, Shermans, T34s, Panthers, Tigers etc. I thought it was just certain compositions of FH that were unweldable the rest just difficult.
The account of Yamatos armour scheme I read said the Japanese came up with a new compostion and made extra large plates to minimize the number of joins in order to reduce the vulnerability of the welds, and rivited for extra strength.
You mentioned that the upper and lower belts were of different types, the upper hard and rigid the lower more flexible, with a structural piece to join them. This could be a weakpoint as shock waves caused by explosions or whatever would respond differently in both materials causing stress fractures. I assume the structural filler was an attempt to cushion this but I can see a serious problem there, the 2 belts could be seperated by a shock wave hitting the junction and bouncing back. Probably not an immediate effect but accumulated damage I believe could open up her side like a zipper!
What do you think?
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Re: Two KGV's vs. Yamato

Post by Bgile »

neil hilton wrote:Hi Dave,

Thanks for the info about welding, I don't know much about it.
Are you sure that all face hardened armour cannot be welded. Mid and late ww2 tanks all used face hardened armour and were welded, Shermans, T34s, Panthers, Tigers etc. I thought it was just certain compositions of FH that were unweldable the rest just difficult.
The account of Yamatos armour scheme I read said the Japanese came up with a new compostion and made extra large plates to minimize the number of joins in order to reduce the vulnerability of the welds, and rivited for extra strength.
You mentioned that the upper and lower belts were of different types, the upper hard and rigid the lower more flexible, with a structural piece to join them. This could be a weakpoint as shock waves caused by explosions or whatever would respond differently in both materials causing stress fractures. I assume the structural filler was an attempt to cushion this but I can see a serious problem there, the 2 belts could be seperated by a shock wave hitting the junction and bouncing back. Probably not an immediate effect but accumulated damage I believe could open up her side like a zipper!
What do you think?
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Re: Two KGV's vs. Yamato

Post by Dave Saxton »

alecsandros wrote: NVNC. Sorry for the typo.
Japan faced nickel and chromium shortages in the 1930s and consequently had to replace some of it in the armor plates.
I guess the adition of Cu also makes the plate pretty much unweldable. However, I did not found any reference so far that would indicate this replacement negatively altered the ballistic properties.

From Nathan's papers, I see that the same replacement - Ni with Cu - was made in MNC. In MNC, however, the amount of carbon was about 0.35-0.42%.

Hmmm...Although not handy I wrote down the MNC composition from either the US or British post war examinations. I recall it as virtually the same as British NCA. Cu in concentrations that low would not impede weldability. In the US examinations of captured Japanese pieces of armour (Metallurgical Study of Enemy Ordnance, Feb 1945) they found many pieces that contained ample quanties of nickel. Although overall they may have needed ersatz nickel, I would expect they would find enough for the relatively finite production needs of MNC.

The use of a copper alloyed material for the lower belt location may have much to do with possible corrosion concerns.
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Re: Two KGV's vs. Yamato

Post by alecsandros »

Dave Saxton wrote: Hmmm...Although not handy I wrote down the MNC composition from either the US or British post war examinations.
I don't have any primary documents, Dave.
I'm skimming through Nathan's papers these days, trying to find some reasonable FH armor penetration formulas. That's why they come so handy :)

From "Table of metallyurgical properties", http://www.navweaps.com/index_nathan/me ... pt2009.htm
I see that he had one source suggesting MNC was based on German Wh, while another source suggested it was based on British NCA.
If I understand his writing correctly, the design specifications of the plates included 0.15% Ni, but supply shortages led to it's replacement by Cu.

My guess is that the Ni available to the navy was diverted for casting the huge plates of VHNC - for the main belt of the 3 Yamato class ships that were launched...
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Re: Two KGV's vs. Yamato

Post by Dave Saxton »

I assume the structural filler was an attempt to cushion this but I can see a serious problem there, the 2 belts could be seperated by a shock wave hitting the junction and bouncing back. Probably not an immediate effect but accumulated damage I believe could open up her side like a zipper!
What do you think?
It appears to be the most efficient means of fitting up the plates to the hull. The upper belt was bolted directly to an inner hull structure. The intermedient structural member between them with the keyway was horizontal and would have prevented the lower belt from easily being driven inward, or the creation of a hinge effect at that point. There's water tight compartments behind it in case of ruptures. In the case of torpedo hits, I'm sure they expected the outer structures including the lower belt to become displaced, distorted and torn.
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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