Scharnhorst and Gneisenau vs Yamato

[Dave Saxton]

The wake or wave form can form a trough just before midships reducing the amount of water that a shell must traverse though to get below the belt. But this only occurs at particular speeds (Pugleise's studies indicated around 30 knots for battleships) and only at a particular spot. It's not likely to happen unless several vairables come to together in combination. It is also depends on the angle of fall. At shallow angles of fall, as would be the case of short ranges, a shell normally must traverse through a lot of sea water before it can pierce the hull below the belt. With Bismarck even if it just passes just below the lower edge of the belt, a shell must travel through more than ten meters of sea water (at short battle ranges). The sea water impares the progress and stability of the shell, and consumes most of its energy. I agree with those whom have the opinion that the IJN under water hit concept was more of an aberation, and that this type of hit ocurring consistently is unlikely.

POW had one of the deepest belts but still suffered a below the belt hit. This was probably due to the wave form while the POW was making high speeds in rough seas, rather than to a strong likelyhood of such a hit ocurring. One of the reasons why the KGV class went to the not so sloped external belts, was because it would be less vunerable to this type of hit at longer battle ranges. With steeply sloped belts, shells falling at plus 25* angle of fall can have a pathway opened up by the belt's slope right downward into the wing tanks, which does not require the shell first to traverse much water. R&R discuss this concern.

The Germans did recognize this vunerability in warships and planned to minimize this in the H-class by extending the belt a bit deeper.

[lwd]

I can understand Bismarck, but why Littorio?

The Littorio's de-capping belt system.

I thought because of her high velocity guns. Doubt a de-capping belt will make much difference at those ranges especially vs Yamato. Still agree a pair of either one or even a mixed pair probably has better odds than the twins.

[paul.mercer]

Bgile:

The 16"/50 AP Mark 8 Mods 1-5 begin penetrating Yamato's deck armor at 34,000 yds. It begins to penetrate citadel vertical armor at 14,000 yds, so the immune zone against that weapon is from 14K to 34K yds. She would be vulnerable at the ranges where Kirishima was engaged.

From what I had read there is no evidence that any shell from USN inventory could do that. In this fantasy the Yamato is as vulnerable as Kirishima on the same ranges, which is, by all practical standards, more than absurd.

No, Kirishima would be vulnerable at any conceivable range, not just below 14,000 yds.

Genltemen,
If Yamato's armour is such that it can resist US 16" at certain ranges what chance do the Twins 11" have except perhaps to ruin the upperworks? Would this not be the equivalent of say a British 8" Cruiser taking on Bismarck? In other words, the quick fire 8" would cause some reletivly minor damage before they were blown out of the water by Bismarck's 15"

[RF]

If Yamato's armour is such that it can resist US 16" at certain ranges what chance do the Twins 11" have except perhaps to ruin the upperworks? Would this not be the equivalent of say a British 8" Cruiser taking on Bismarck? In other words, the quick fire 8" would cause some reletivly minor damage before they were blown out of the water by Bismarck's 15"

It is believed that an 8 inch shell from Norfolk struck Bismarck's foretop and knocked out the main gunnery control just after Bismarck found the range of Rodney at the start of the final battle on 27 May.
And let us not forget the damage caused by the 8 inch hits by Prinz Eugen on Hood and POW three days earlier.

[Karl Heidenreich]

paul.mercer:

Genltemen,
If Yamato's armour is such that it can resist US 16" at certain ranges what chance do the Twins 11" have except perhaps to ruin the upperworks? Would this not be the equivalent of say a British 8" Cruiser taking on Bismarck? In other words, the quick fire 8" would cause some reletivly minor damage before they were blown out of the water by Bismarck's 15"

My point all along. There is now way on Earth that a USN 16" gunned battleship could be a real threat to Yamato, then the Twins are just a joke here.

[lwd]

paul.mercer:

Genltemen,
If Yamato's armour is such that it can resist US 16" at certain ranges what chance do the Twins 11" have except perhaps to ruin the upperworks? Would this not be the equivalent of say a British 8" Cruiser taking on Bismarck? In other words, the quick fire 8" would cause some reletivly minor damage before they were blown out of the water by Bismarck's 15"

My point all along. There is now way on Earth that a USN 16" gunned battleship could be a real threat to Yamato, then the Twins are just a joke here.

But of course a USN 16" gunned BB were a very real threat to Yamato. Furthermore at ranges equivalant to those of say Washingtion vs Kirishima the twins can punch through all of Yamato's armor except the faceplates of her turrets.

[Thorsten Wahl]

I think there is no valueable target to risk the twins against a Yamato.

[paul.mercer]

If Yamato's armour is such that it can resist US 16" at certain ranges what chance do the Twins 11" have except perhaps to ruin the upperworks? Would this not be the equivalent of say a British 8" Cruiser taking on Bismarck? In other words, the quick fire 8" would cause some reletivly minor damage before they were blown out of the water by Bismarck's 15"

It is believed that an 8 inch shell from Norfolk struck Bismarck's foretop and knocked out the main gunnery control just after Bismarck found the range of Rodney at the start of the final battle on 27 May.
And let us not forget the damage caused by the 8 inch hits by Prinz Eugen on Hood and POW three days earlier.

I agree, Norfolk did the same to Scharnhorst at the Cape, but there is no way the 8" fire from PE was going to sink PoW or 8" fire from Norfolk would sink Scharnhorst. I think the original thread was about the twins taking on and defeating, if not actually sinking Yamato.
I just don't think they would.

[lwd]

I think most here agree that it would be a very uneven match up and the odds would not be with the twins. However if they got lucky, especially if the conditions were very favoreable they might have a chance. The "knife fight" is one area that would tend to give them the best chance another would be a very long range engagement. In the close range engagment the number of guns the twins had combined with thier high rate of fire and flat shooting vs a large target should produce hits much faster than the Yamato would. Since they could penetrate most of Yamato's armor at close range then they have a chance of disableing her before she returns the favor. The long range engagement relies on luck and RFC to degrade Yamato's fire control (or some other lucky curcumsance) before the Yamato does critical damage to the twins.

[Karl Heidenreich]

Lee:

But of course a USN 16" gunned BB were a very real threat to Yamato. Furthermore at ranges equivalant to those of say Washingtion vs Kirishima the twins can punch through all of Yamato's armor except the faceplates of her turrets.

This answer confirms what some of us has commented: we came forward with evidence and direct sources to made a point. This point has been accepted, or was not challenged at all. And then, months after you came again with the old common wisdom stance that shows that you still don't get it.

Ok. Here we go again in the context of the Twins vs. Yamato. Simply put the Twins do not stand a chance because even heavier units cannot. If making plain evident that an Iowa Class battleship is in the low side in a match against the Yamato, then by logic the Twins could not.

First, let's see what an accepted sources, as Richard Worth, have to say on this issue:

Right through the end of WWII, optically trained gunnery was superior to radar-trained gunnery. Mo will shoot best when she can see the target.
Things are best for the Americans if they can strike a decisive blow before the range closes under 30,000 yards, where Yamato is in her immune zone. Mo has no immune zone. If the ships make contact at less than 30,000 yards, Yamato has a huge advantage.
Yamato's 46cm faceplates are effectively impenetrable. Mo also has thick faceplates, but unfortunately for her they are made of homogenous armor. Japanese shells appear to have been very poor against face-hardened armor but very good against homogenous armor.

The sentence from the author here is quite important: "Mo has no immune zone" Which is incredibly relevant to our discussion.

Worth's answer to the question of "... The fact is the 16" shells of the Mo where just as capable as the 18" shells of the Yamato." he answered:

No. Not at all. A 46cm shell inflicts roughly 20% more striking energy, weighs 20% more, and contains 20% more explosive. There are advantages for the US shell, but Japanese shell will tend to be much more destructive.

Again we have a categorical answer.

Of course, someone can come telling us that Iowa's armour strong enough to resist Yamato's 18". In this we have the following statement:

American homogenous armor was among the best. American face-hardened armor, in its battleship application, was among the worst in the world. In fact, against shells as large as Yamato's 46cm AP, it was THE worst among the major navies.

When the counterpart in the discussion insisted, as lwd does, on "... The Iowas were both fast and well armored" the answer is, again, categorical:

Well armored against what? It has already been noted that the Iowas had no IZ against 46cm shells.

The last remark, here, is more like mine than anybodies else's, but came from this same discussion:

Was the trawler at Truk the only enemy ship sunk by the four Iowa class ships?

...If there is a need to differentiate between American and Japanese battleships, there is one characteristic comparison that eclipses all others, and it can be expressed in this way: 27-12.

From this side of the issue I think there is no further need to continue. But in other threads some other important points have been raised, so I proceed to brign them forth to "remind" those USN followers that the most powerfull battleship ever made wasn't American, but Japanese. It continues in a following post:

[Karl Heidenreich]

The Twins cannot even dream in match a Yamato Class battleship in a fight because even stronger units were not capable to do so. This is the case of an Iowa Class battleship against Yamato. Iowa was heavier, with bigger guns than any of the Twins... and was, also, the lesser ship when facing Yamato.

Even if we ignore Richard Worth's comments here, or Friedman's or Garzke and Dullin we can come forth to the source of the famous Yamato researcher Skulsky.

"Her 46 cm (18 in)guns, with 42-44km range and SUPERIOR optics equipment, were the largest and most MODERN naval guns ever mounted and FAR EXCEEDED the quality and construction of other countries... Her 15 m rangefinders gave tremendous presicion to the main gunfire; her armour protection was 650mm thick and the side armour plate 410mm; and the shape of her hull reduced water resistance to a minimun..."
- Yamato: Anatomy of a Ship

Yamato´s armour, everybody knows, was the heavier ever given to any warship in the world and stands alone a record until this day. But what is not being said a lot about it was that Yamato´s main section was protected by a:

"sort of collosal armoured box. The box sides were protected a the top by 410 mm VH armour plating, which was DESIGNED TO WITHSTAND 46 CM AP PROJECTILES FIRED FROM A DISTANCE OF MORE THAN 20,000m. The front and back of the box were protected by 340-300mm VH steel armour. From above the armour deck made of MNC steel armour plating 200-230mm thick formed protection against 46 CM AP PROJECTILES FIRED FROM A DISTANCE OF 30,000m and could be penetrated only by a 1,000 kg AP bomb dropped from a heigh of 3,400m or more..."
- Yamato: Anatomy of a Ship

Yamato was desgined to resist the thrust and energy from 18" shells that weight 1,460 kg and travelling at 500m/sec. Yamato was not design to withstand 16" guns but 18".

The AP shell was designed to go into the water short of the target, maintain it´s trajectory and penetrate the enemy´s TDS. The projectile nose was hidrodynamic so that her trajectory would not be changed by the impact and dive into the water.

But let´s see what the 46 cm shell could do:

At 20,000 meters

Gun elevation: 12 degrees 34´
Striking angle: 16 degrees 31´
Striking velocity (m/sec): 522
Penetration vertical plate (mm): 566
Penetration horizontal plate (mm): 416

At 30,000 meters
Gun elevation: 23 degrees 12´
Striking angle: 31 degrees 21´
Striking velocity (m/sec): 475
Penetration vertical plate (mm): 167
Penetration horizontal plate (mm): 230

And Iowa´s armour was distributed as follows:

Belt: 12.1 in (307 mm),
Bulkheads: 11.3 in (287 mm),
Barbettes: 11.6 to 17.3 in (295 to 439 mm),
Turrets: 19.7 in (500 mm),
Decks: 7.5 in (191 mm)

Iowa´s was quite vulnerable, as you can see, at both ranges, against Yamato´s hits against her main belt and deck armour. At greater distances Yamato´s plunging fire would be to Iowa what Bismarck´s one was to Hood...
But Yamato was not vulnerable to Iowa´s shells because she was designed to withstand not 40,6 cm but 46 cm AP shells.

We should also note (and this if likely OT because goes only in the direction of Iowa's weakness against contemporary ships that cannot be extrapolated to the Twins) that:

dunmuro:

The magazine placement of the USN fast BB designs was highly vulnerable, and not much better than Hood's. If we replaced Hood with Iowa, there's a chance that she will be destroyed by the same hit that destroyed Hood, while Washington would certainly have suffered the same fate as Hood (assuming the same range and target angle from Bismarck as Hood, when she was blown up).

If to all the above mentioned reasons we add those comments from Friedman, Raven and Roberts, Garzke and Dullin and Skulsky as from Chuck Hawks then we can be settled: Yamato is the very likely winner in a naval combat against the USS Iowa, which is heavier and with bigger guns than the Twins, so by extrapolation the Twins, even both of them, are likely the losers in such a combat.

Let's hope that months from now memory still works on this issue.

[Karl Heidenreich]

This is document I found two or three years ago while searching the internet. I will post it here for all those interested in this topic of USS Iowa Class vs a Yamato. I place in the same context that both previous posts, in order to dispell the issue of the Twins vs Yamato by proving that a heavier ship (the Iowa) could not deal with Yamato in favorable terms. Here it is:

Hi Robert:

I think you should review Strafford Morss’ article in Warship International, No. 2, 1986, pp. 118-136. This will provide details on just how poor our intelligence was about the Yamato class, and where a “desired” range should be maintained in light of the information we had. We assumed the Yamato had 12” side armor and 6.4” deck plating. It was thus calculated that the ship had a 1,000 yard advantage (31 vs 30K) over a So. Dak./Iowa class in terms of deck protection against the 16”/45 caliber guns we thought it was armed with versus the US 16”/45 gun against the Yamato’s deck. We now know the Yamato’s deck armor was far thicker and that it’s guns were larger, but let us remain in the hazy past. In terms of the inner edge of the immune zone, ONI assumed the Yamato’s belt was 12” thick, but didn’t assume it was angled. The ship was thus supposedly vulnerable to the US 16”/45 guns at about 14K, at least according to our estimations. Conversely, the US ship was supposed to be proof from 16”/45 fire out to 21K.

Accordingly, the Yamato’s calculated IZ was 21-31K against the US 16”/45, while the Iowa/South Dakota were accorded an IZ of 14-30K against the Japanese 16”/45. The zone wherein the US ship was supposed to have enjoyed an IZ advantage was thus 14-21K. Of course, the 16”/50 would shrink the inner edge calculations of Yamato’s IZ and slightly expand its outer edge, although the Iowa’s own vulnerability against the Yamato’s guns would be nearly the same as in the South Dakota Class due to its nearly identical armoring scheme.

Based on this information, the US commander would have thought it “safe” to rapidly close to under 31K to avoid deck penetrations, and to quickly seek the sweet spot at 14-21K. The numbers of hits expected at 26K and beyond, which is relatively constant, was expected to only be 0.75-1.0 rounds for every three minutes (as in Morss’ example of 18 hits in 65 minutes at 34K while 296 rounds were expended). I find these numbers overly optimistic, but they certainly imply a rapid approach will help avoid the possibility of a hit that could penetrate decks at 30K and beyond.

Given all of the above, it is quite likely that fire would have opened at beyond 30K, although the range would have rapidly closed to under 30K. Moreover, given the presumed zone of mutual immunity, there is every reason to believe the range would have been closed to 20K or less as the US commander sought to use his supposed window of advantage. This would most assuredly not have been a good thing for the Iowa. Indeed, the Yamato’s actual IZ against the 16”/50 was around 17-33K, depending on what formula one uses, while the Iowa’s IZ against 18.1 shells is about 26-30K. In short, the Iowa would be playing into the Yamato’s sweet spot, and inside the sub-21K range the US commander would seek his ship would likely be devastated in very short order.

Now, we are dealing with intelligence estimates, and not realities. In terms of likely battle scenarios, context will play a huge part that cannot be accurately modeled (e.g., night vs day, rain vs clear conditions). But in general, one expects both ships will open fire ASAP while striving to maintain what each feels is the idea zone. One surmises the Yamato’s commander may be inclined to allow the Iowa to close as quickly as she likes – as would a spider to a fly.

With regard to shell penetration, I would ask you to compare the shell head shapes of the Type 95 projectile the Yamato used with the late war US 16” 2700 pound shells. You will find that they are very similar in form, with both having extremely rounded heads. This optimized deck penetration, while slightly degrading penetration at normal angles relative to projectiles with more pointed forms. Thus, the Japanese shell was optimized for both underwater travel and deck penetration. However, the way the shell was optimized for underwater travel was related to how it lost its ballistic screen and AP cap, as well as it shape. Here we find both US and Japanese heavy shells have a history of being relatively easily decapped (which is not to say, effectively decapped), so there is not much advantage going to either side here. However, the Yamato’s shell is far heavier, and herein resides it advantage in penetration.

The quality of steel that was used to build the Yamato and its armor has been a source of contention. However, we have found a number of Admiralty records that report tests done on both hardened and homogeneous Japanese plates, and their results are wildly different from the one US study on this subject I’ve seen quoted so widely -- and from which so many have drawn such broad conclusions. Indeed, the thicker Japanese plates performed markedly better than their British counterparts, both in terms of British CA and homogeneous plates. One notes here that British cemented armor was far superior to US Class A in resisting penetration, with the percentage varying in relationship to the size of the attacking shell (15-25%).

In addition, US Class A has a huge scaling effect due to the extreme thickness of its face, and thus it performs worse as shell size increases – and the 18.1” shell was the largest used during WWII. This would not bode well for the Iowa, but what about the Yamato’s belt armor? The Japanese vertical armor was made by a different process, and had a thinner face. Regrettably, the Japanese “lost” many of the proving ground records associated with the Yamato’s armor during the war, so all we have are our own, British, and surviving Japanese data. Thus nothing conclusive can be said here, other than it is folly to assume the Japanese armor was inherently less resistant that US plates. Moreover, they were 33% thicker.

In terms of deck armor, US Class B performed better than its British equivalent, but so to did a thick Japanese homogeneous plate the British tested. Here again, nothing definitive can be said about relative armor quality, although the Japanese deck armor is much thicker than that used on the US ship. I suspect the armor trials Japan conducted on the Yamato’s armor may turn up one day, but I’ve found no conclusive reason to accept either the British or American findings on this matter. I think the collective data on all the trial results should be averaged out, but this is not politically acceptable. It would serve to make the Japanese armor “better” than some might like, which is why these data are not currently collapsed in the available pool. This bothers me to no end, and is not the stuff of science.

As for the disposition of each ship’s armor, it is remarkably similar. Both vessels employed inclined side plating, the lower strakes of which became progressively thinner and used homogeneous material as they formed the main TBD barrier. These bulkheads also proved incapable of deforming enough to accept the blast pressures created by torpedoes, which shows that parallel solutions can create similar problems. The upper joint between the hardened anti-shell and more ductile anti-torpedo plating was common to both designs, although only in the Yamato class was a problem revealed by actual war experience in this potential area of weakness. The lower aspect of the American TBD system was revealed to be a weak point during caisson trials, and palliative measures involving shifting liquid loads were only partially effective.

Both ships had very short citadels relative to other designs, leaving them vulnerable to bow and stern damage form even light weapons – a common curse in all-or-nothing designs. However, one key difference was that the Iowa’s deck armor did not extend to the ship’s sides, and this left about 7-8 percent of its width unprotected. The impacted regions were in the wing-tank areas, which left the water-plane far more vulnerable to damage from bombs and shells of many calibers. This was exacerbated by the Iowa’s use of an inclined internal armor belt, with the main concern here being to stop diving shells. Indeed, both ships were designed to combat this possibility, albeit at the cost of a lot of other passive protection characteristics.

Indeed, a shell exploding between the belt and skin plating could have dire consequences. One notes the thick Class B section of the belt could probably have stopped shell splinters and even diving shell hits, but their blast forces would be vectored outboard. This could blow out or riddle large portions of the water-plane area, and this would result in lists and drastic speed losses. A shell that hits at an axial angle in the water-plane area would be even more dangerous. Such a shell could rip open wing-tank compartments over a great length of the ship, all of which would be exposed to sea – and especially so if the shell exploded at the end of its run. It is thus no wonder the USN abandoned the internal raft approach in the Montana class.

I know next to nothing about Japanese fire control, and am not fit to make a judgment. However, I have records that demonstrate US shells had some serious corrosion-related fuze problems, and that our fire control computers needed modifications to perform properly. Much of this was due to an incorrect temperature assessment being given to the propellant when the cams were designed that provided FC solutions, although faulty wear tables and other factors were also in play. As a result, the cams incorporated algorithmic functions that were incorrect, and the end effect was a tendency to shoot long by up to 1,200 yards. Barrel whip was also a problem, and thus the new guns tended to undershoot when aiming at close targets.

The confluence of these unhappy tendencies was vexing, and may explain why it took until 1945 to figure out what was going on. A new set of cams was built for the FC computers, but it wasn’t installed until after the war. In mid to late 1944 a series of formal trials was conducted to come up with an optimal solution, and I presume some range-correction tables were made by 1945. I am not sure about this, but it stands to reason. Thus, the effectiveness of US gunfire will depend on the time and type of ships that are being considered, with my money resting on the old BBs prior to mid-1945.

The US Mark 8 Mod 1 radar was an effective FC model, but the prior marks were not panaceas. Moreover, all radar is impacted by weather conditions, with its range and accuracy being cut by 33% and more depending on the relative humidity. This is an odd but true finding. So you would have to define the weather in the battle area to properly calculate the influence radar would have -- and also where the battle took place. In fact, islands and similar land mass played havoc with early radars, although these problems were largely ironed out by 1945.

Firing while maneuvering is an interesting area, and I know the US was working on it throughout the war. Yet it appears that we were not alone. I am currently engaged in helping to translate the PE war diary and it mentions having to turn at least three times while firing. On two of the turns it lost the FC solution, but on the third it was ordered not to fire over the Bismarck. The degree to which these systems were perfected in terms of practical applications is unclear. I know all navies conducted experiments in this procedure, but I’ve not seen enough records of British, German, and Japanese developments to say which nations had the edge. Furthermore, I doubt many people have, although we’re always looking for this information.

Overall, I think the Iowa would be well advised to stay away from the Yamato, and not to engage it at all. The Iowa’s greatest advantages were her speed, range, and AA potential. She was never intended to be a brawler, and certainly lacked the vertical armor to engage in any close range fighting with the Yamato. If an Iowa’s commander acted in accord with US intelligence reports, he would have played right into the Yamato’s strengths. People spill a lot of cyber blood over the Yamato versus the Iowa, but each was kind of its own realm. The Yamato had the edge in terms of several criteria (armor, guns, size, etc.) while the Iowa was fast and long-legged. Yet one Essex class CV was a greater threat to the Yamato than an Iowa. Well, I’ve got to get back to my book on the Littorios. Still, this will give you a few things to consider and research. Feel free to contact me directly for the reports I have.

George

[Bgile]

Karl,

From your quote above:

"the Yamato’s actual IZ against the 16”/50 was around 17-33K, depending on what formula one uses ..."

So clearly in the engagement against Kirishima if we substitute Yamato, we are outside her immune zone as well (less than 9,000 yds and her immune zone only goes down to 17,000 yds), and 16" guns will be able to penetrate her citadel. Both ships are able to penetrate each other's armor.

[Karl Heidenreich]

Bgile:

Karl,

From your quote above:

"the Yamato’s actual IZ against the 16”/50 was around 17-33K, depending on what formula one uses ..."

So clearly in the engagement against Kirishima if we substitute Yamato, we are outside her immune zone as well (less than 9,000 yds and her immune zone only goes down to 17,000 yds), and 16" guns will be able to penetrate her citadel. Both ships are able to penetrate each other's armor.

Can you imagine what the 18" of Yamato could have done to South Dakota (after SD miserable performance of firing salvo after salvo and hitting nothing when the combat started?) Instead of 14" of HE we are talking 18" aimed with the finest stereoscopic optics in the world. The combat will change completely with South Dak sinking in flames and USS Washington trying to make some damage. Yamato has more chances to absorb punishment, which can maybe be near to nil as for what we have read from all the authors put together. Don't believe neither of the overated USN battleships will survive the night, honestly, ideology is hardly part of naval warfare.

[alecsandros]

Hi Karl,

Regarding your lengthy quote above: in the past years, several important primary documents and/or thorough analysis have surfaced, proving many of the previous estimates, claims or speculations about Yamato's capability's were un-founded.

That being said, from the informations I read so far, concerning the technological realities of the Japanese behemoth, I don't think it would have been so effective as you may believe.

The design may have been formidable, but the real ship was something else...