All hits are not equal, even if they all penetrate. They vary in their destructive effect, and the significance of that destructive effect also depends (on average, discounting lucky hits) on the size of the target. For instance, other things being equal, a given flooding rate will sink a small ship faster than a big one.

Yamato weighed 69,000 tons, Bismarck 46,000. Yamato's AP shells weighed 3,230 lb, Bismarck's 1,764 lb. So the Yamato was 1.5x heavier and its shells were 1.83x heavier. Multiply those out and you will find that (on average and roughly speaking) a penetrating hit by Yamato on Bismarck would be likely to be about 2.75x more destructive than a penetrating hit by Bismarck on Yamato. [Edit to add: in simple terms, that means that it would take 11 hits by Bismarck on Yamato to equal the effect of 4 hits by Yamato on Bismarck. Yamato will also be firing with 9 barrels rather than 8, giving a 12.5% better chance of scoring a hit.]

As far as gunnery effectiveness is concerned, the Japanese were highly trained and very effective at the start of the war, especially in night fighting. Their performance fell off badly late in the war, presumably as a result of the same problem which affected their air forces: combat losses of skilled men, plus an inadequate training regime to bring forward replacements.

So I think we need to clarify whether we are comparing ships or their crews; and if their crews, at which stage of the war.

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Tony Williams: Military gun and ammunition website

reaily good question this one maybe the yamato scence it wos a bit more moden ??

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Firstly I have to say that the Bismarck is my favourite vessel of all time.

Ok with the out of the way what I really hate about the Bismarck is that she over glorified I mean I have two books about Battleships and she takes up about 4 pages all by herself, yes she was the most powerful ship in the Kriegsmarine and yes she did sink HMS Hood, but other that she did virtually nothing to help the Germans win the war, on her first sortie into the Atlantic she got herself sunk, heck she didn't even get into the Atlantic. There are songs about 'Sink the Bismark' and how she made Britains afraid when she was at sea, what a load of heap, she was one ship and her and her sister Tirpitz were never going to take on the RN and win the war for the Germans.

These raids that the Germans did, did nothing except sink a few ships and divert ships from Britains defence which ended in not winning the war, they were never going to 'starve Britain into submission' with there Navy at the time. Even if the Germans could divert the ships from Britains defense they still wouldn't have had enough ships themselves to take on the RN.

Anyway ranting over back to the point

Although I like the Bismarck itself I would have to lean towards the Yamato although the German range finding equippment would have came in handy in a night engagment. I think the Yamato's sheer size over the Bismarck would win the engagment for her, although I do not think that she would walk away unhurt from the battle. The only way the Bismarck could have won was a lucky shot into a magazine or onto the propeller shafts and literally make yamato a sitting duck.

But I am going with the Yamato.

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But, either round is sufficently destructive that a handful of solid hits by either ship wrecks the other pretty thoroughly. Note that during the war actual results of battleship on battleship action show as few as 5 to 10 solid hits are all that is necessary to reduce an opponet to ineffectiveness.
In this particular case, both ships will be firing at a range where deck penetrations are unlikely due to the low angle of fall; although it is more likely that Bismarck would suffer a penetration of her deck armor system than Yamato. This is due to the nature of glancing hits where shell overmatch (that is the sheer weight and kinetic energy of the round exceeds the compressive strength of the armor struck causing it to fail inelastically....eg., shatter) is likely to make the thin decks on Bismarck fail even when not actually penetrated.
One thing not mentioned here is rate of fire. At best, Yamato can manage about 1.5 rounds per minute per gun while Bismarck does 2. This means after five minutes of fire the Bismarck has put 80 rounds down range compared to 67 for Yamato. In this case the extra gun on the Japanese ship does not equte to greater rate of fire. Compounding this is that the Japanese loading system is heavily dependent on manual operations during its cycle. This means their rate of fire will drop off fairly quickly as the turret crew tires.

As far as crews go, I was leaning towards their being roughly equally well trained. I would still say first on target wins the engagement, and that is more likely going to be, in this case, Bismarck.

Battleships were generally designed to resist damage from guns equivalent to the ones they were armed with: hence the importance of "immune zones" in design (the zone within which the ship was too far away for specified guns to penetrate the side armour, but too close for them to penetrate the deck armour).

The importance of rate of fire depends on the engagement range. Battleships didn't carry many shells (typically 100 rpg - not necessarily all AP) and they waited to observe the fall of shot so they could correct the aim before firing again; and at long range, shells could take well over a minute to arrive.

To sum up, battleship designers and navies were very well aware at the time of the importance of displacement: the need to achieve reasonable speed together with good armour protection and guns powerful enough to penetrate that armour kept pushing up displacements. Just look at the wild designs German naval architects came up with for "super-Bismarcks" with guns of up to 20" calibre. Why would they bother, if the Bismarck was so good? With battleships, bigger was better (other things being more or less equal).

This site probably makes the most detailed attempt at analysing the strengths and weaknesses of WW2 battleships, and it rates the Yamato as clearly superior to the Bismarck: Battleship Comparison

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Tony Williams: Military gun and ammunition website

wow haha where di you get that one from

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Its basic metallurgy. This is usually discussed about tanks and their armor rather than ships but the same principle applies.
From the tank perspective imagine say a T 34 with roughly 2" thick (actual thickness) frontal armor (47mm). This is sloped to make it almost the equivalent of 4" vertical plate. But, the actual plate is still only 2" thick.
Now, we will fire a 105mm heavy wall HE shell at this plate. The round weighs about 30 lbs and has an HE filler. Technically, this round should not be able to penetrate a 4" plate. Certainly, if we fired it at a vertical 4" plate it wouldn't penetrate. But, in this case what happens is the round's kinetic energy (mass x velocity) is such that the amount of force applied to the 2" plate regardless of slope is sufficent to cause it to fail and the round penetrates destroying the tank.
This exact...exact thing occured in the action between Hood and the Dunkirque at Mers el Kabir. A 15" shell from Hood struck the roof #2 turret of Dunkirque at a very obliqe angle (at the range of fire at the time Hood's shells would have been falling at roughly 10 degrees). Theoretically, the roof armor of the turret should have been sufficent to stop the shell. But, instead, due to its massive weight it shattered the armor leaving a gouge several feet long. The shell didn't actually enter the turret but the fragments from the shattered armor did, ignited loose powder in that half of the turret and wiped out the turret crew knocking the turret out.
At Jutland the same thing happened several times to various British battlecruisers too. This is not an isolated occurance. In a Bismarck v. Yamato fight we likely would see the same thing. In fact, it is very possible that this very mechanism was responsible for the demise of the Hood at Denmark Straight as the theoretical performance of Bismarck's 15" guns should not have been able to penetrate Hood's deck armor over the magazines at that range. But, Hood's deck was relatively thin and a oblique strike would have almost certainly resulted in a shattering of the armor through overmatch.

Here are the conclusions I reached reviewing every battleship on battleship action of WW 2. Note, they contradict in many cases the technical analysis and conclusions of the article comparing battleships cited elsewhere here.

* He who shoots first and hits generally wins. In all eleven cases above, the side that got on target first won the action and usually won it handily.

* Large caliber battleship shell hits are extremely effective when they strike areas of their target ship's vital systems. At the same time, smaller caliber gunfire rarely contributes much to the destruction of a battleship except when the odd hit on such systems as lightly armored fire control stations or radars occur.

* Heavy armor is usually inadequate to prevent serious damage from major caliber hits even when it is not penetrated. Note how even glancing hits on main battery turrets in several cases resulted in a temporary or permanent (in terms of the battle space) loss of that turret.

* Speed is only an advantage in avoiding action not in continuing it. In every case above the faster ship(s) only used their speed for escape not to close or maneuver with the enemy. In the one case where one side tried to use speed to close tactically (Denmark Straight) it proved of no real value in terms of the outcome.

* Usually one or two shell hits at or below the waterline are sufficient to negate the superior speed of an opponent's ship. Shell hits in these areas generally allow for substantial flooding such that the added weight, and often additional weight of counter flooding to reduce list are such to reduce speed on their own irrespective of damage to vital systems. The problem here is one of mechanics. Propulsive power to speed is a cubic function. That is to double a ship's speed takes roughly a cube of the horsepower at the lower speed. This results in a very quick loss of speed when weight is added or even small amounts of propulsive power is lost.

* In most weather conditions and at night a superior radar fire control system is a huge advantage over search radar and optical systems. The advent of radar and by mid-war of centimeter and millimeter wavelength radars in particular, virtually negated any value a superior optical rangefinder would give. The late war US Mk 8 radar was about ten times more accurate at 30,000 yards as the optical systems mounted on battleships using it. This advantage cannot be overstated. It is a primary cause of the loss of more than one Axis battleship. Even the differences in quality of mid to late war Allied search radars compared to Axis models gave the Allies a huge advantage tactically. This proved to be a critical weakness of both German and Japanese battleships; a lack of adequate radar systems. In the German case, it was primarily a failure to develop naval radar beyond the initial set Seetakt. By late war the German navy was relying primarily on makeshift applications of Luftwaffe radar sets aboard their ships. This was hardly a useful substitute. The Japanese on the other hand did develop a number of decent radar systems for ships including the millimeter wave length 2 Go 2 Gata 4 Kai S fire control set that began to be installed on ships in August 1944. This and other sets put them ahead of the Germans in the use of radar at sea. The Japanese main problem was one of manufacturing capacity. They simply lacked the means to manufacture enough sets quickly to deploy them early and widely.

* Battleships operating in pairs or groups have a tremendous advantage over a single ship even when that single vessel is superior in technical qualities.

* Loss of centralized fire control is usually fatal. Battleships operating in local control are almost universally unable to bring effective fire on an opponent. Note how in every action listed once a battleship was forced to use local control it was unable to score hits on opponents even at relatively close range. While mounted very widely, turret rangefinders were just a waste of weight and space given the results of battle.

* Optical fire control has a maximum practical range of about 20,000 yards under most circumstances. In none of the actions cited did a battleship open fire much beyond this range when using optical fire control. The same range, 20,000 yards, is also typically about the maximum effective gunnery range regardless of the fire control system. Note that the longest ranged hit in any of these engagements was by Warspite at Calabria at a range of about 26,000 yards. At Surigao Straight the US waited until the range decreased to about 20,000 yards to ensure more hits even though their ships had fire control solutions at much greater ranges in many cases.

* The diving shell threat is serious but it is highly overrated. The likelihood of getting such hits is very low. But, when such hits do occur they can be very damaging. The Japanese went so far as to develop special shells that could follow a reliable underwater trajectory for this purpose. The trade-off for them was a general degradation of armor penetrating performance in other situations. In hindsight, it was a poor trade.

Oh ok I didn't know much about armour penetrattion tankyou gardner it does make sense

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i'll add something to ta's conclusions: deployment. BBs were basically used in three ways during ww2:

1. area denial (lutzow, graf spee, bismark, tirpitz, prince of wales-repulse)
2. interception-specific engagement (against bismark, against kirishima, against 7th fleet, at surigao strait, against ozawa's decoy force.)
3. shore bombardment

#3 is self-explanatory. #1 all ended in failure. only #2 proved effective and each instance involved a modicum of luck.

the main lesson: when in a battleship, don't parade yourself and invite others to come to your party. instead, invite yourself through someone's back door.

I don't disagree with any of that, but I don't see it as contradicting the technical analyses comparing shell weight, destructiveness, and the ability of a ship to withstand damage.

What you are basically saying (and I agree) is that in each case of combat involving battleships, specific factors, unique in each case, were more important than issues such as shell weight, penetration, destructiveness and armour thicknesses (or even fire control - if your fire control is knocked out by a lucky hit). A good example might be Guadalcanal, at which the old battleship Kirishima gave South Dakota a very rough time (which shouldn't have happened) before being crushed by Washington.

However, that doesn't help us much in comparing the potential performance of battleships, in which we have to follow the naval architects who spent their lives designing ships which matched or beat the characteristics of the likely opposition. Such comparisons inevitably have to be on an "on average" basis, discounting the effects of tactical surprise, better radar (radar wasn't a factor in battleship design, and in practice its quality varied over time anyway, as you have observed) and so on. To put it another way, if we're going to compare ships at all, we need to assume that a one-on-one fight is run many times over in order to obtain typical results, with tactical and other individual factors cancelled out.

Incidentally, do you have a source for immune zone figures for Bismarck and Yamato against each other?

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Once more into the Abyss....

There's also the Ker-Blewie factor. (I just made that up)

Both were leaking oil, on fire (before Davy Jones), pummeled, hulled, holed, and rolled.

Only Yamato.............went...........Ker-Blewie

Bismarck sits upright (almost) in one (hull) piece.

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Morbius, Morbius! Something is approaching from the Southwest. It is now quite close.

This is rough but close enough for most purposes:

Bismarck's armor Belt: 12.5" Deck 2" + 3 1/2"
Yamato's armor Belt 16" (with slope 18") Deck 7 1/2"

Yamato is immune to Bismarck at 25,000 yards or more vertically and at all ranges horizontally.

Bismark is immune to Yamato beyond 35,000 yards vertically and under approxmately 15,000 yards horizontally.

The reason I used round numbers is because there is of course some performance differences between the specs in various sources and in Bismarck's case the nature of the protective system. Bismarck has two armored decks. The upper is 2" penetrated by Yamato down to about 10,000 yards. The lower is 3 1/2 inches and penetrated beyond about 17,000 yards. The first is going to have some effect on whether the second is penetrated so, I roughly split the difference.
Of course, the ships are not equally armored over their entire citadel nor over the entire length of the ship. But, the above gives a good first approximation of vulnerability.

Since history shows battleship fights virtually always will occur at 20,000 yards or less both ships are inside their vertical vulnerability zones while Yamato does have the advantage of a theroetically unpenetratable deck.

Another unpredictable is how each side will fire their guns. With bagged charges it is possible to fire using a reduced charge in order to get greater drop at some ranges. The Yamato has an advantage here in that her guns will elevate to 45 degrees while the Bismarck is limited to 30 degrees elevation. Obviously, the German designers intended the Bismarck to fire fairly flat trajectory rounds at high velocity and weren't overly worried about achieving maximum gun range.
The Japanese could, theoretically, at ranges of about 15,000 yards or more fire at high elevation using reduced charges to obtain plunging shell fire. This would change the penetration tables substancially from just full charge fire.
Also, both ships have 6" secondary batteries capable of reaching to about 20,000 yards too. These could have an effect on deck strikes as they would be firing at much higher elevations to achieve that range. Although in the case of Yamato her deck armor is still impervious to hits from 6" fire. In Bismarck's case the 2" upper deck is still vulnerable to 6" fire at long range.

T.A., Tony . . . great posts. The stuff you shared were enjoyable to read though I admit I did get a slight headache when crunching numbers were involved. Still to you too, great exchange of information that all of us here in the forum will surely benefit from.

Thanks, that's helpful.

It would be nice of there were a computer programme with all of the variables involved (tactical as well as technical) so that Yamato v Bismarck could be run 100 times over in various circumstances, since that would provide a clear idea of their strengths and weaknesses.

Picking out single examples of engagements doesn't tell you much, because almost anything could happen once. For instance, I recall reading that the rear gunner of a Ju 87 (firing a 7.92mm MG) once shot down a P-61 Black Widow which was stalking it at night (armament 4x20mm, 4x.5"). That does not make the 7.92mm MG a satisfactory defensive weapon against a P-61 - except in that one instance!

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I have a really old (written in GWBasic) program that actually does all the caluclations. Got it out of an old Warship International It calculates the trajectory based on elevation, shell (a number of pramaters here like CHR, weight, etc.) air temperature, wind, gun elevation, and such. Penetration is calculated using the US Immunity Zone Slide Rule. This is theoretical rather than actual but usually comes out within an inch or so of actual penetration.
It might be available on line I'll have a look. I believe it was written by Nathan Orkim or some something similar to that.

That'll be Nathan Okun, who produced the comparative analysis I provided a link to previously.

I suspect that all the programme does is look at penetration (and does that take into account that the ships are likely to be at an angle to each other, rather than exactly parallel?). From your description, it may also not take into account the greater radius of destruction of an 18" shell over a 15" one when they detonate after penetration, nor the capacity of different ships to withstand a given amount of damage (which is largely linked to displacement, as I said).

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In my opinion the one that spot first will win the battle.

I don't agree with the ranges that are being proposed. Both US and Japanese doctrine was to fight at longer ranges. Yamato will try to fight most probably in the 25,000 to 30,000 yard range. At that range even a single solid hit from her will really hurt Bismark. Bismark on the other hand can't penetrate most of Yamato's armor at that range. I suspect that at those ranges if Yamato's shells don't detonate they have a decent chance of exiting the bottom or lower hull of Bismark.

Also consider that while some have suggested Bismark is more resitant to diving shells Yamato's shells are specificlly designed to function well in this mode. Given their weight I think Yamato is in better shape taking diving shells than Bismark if the two are fighting each other.

Bismark's only real hope in my opinion is that for some reason the engagement sarts at short range and stays there and that she is lucky enough to get in several telling hits before Yamato.