Nathan Okun's Reply (Was: Possible Kill Shot from Ansaldo 1934 to Bismarck)

[BaryOnyxx]

Hello Friends,

 

    Mr. Nathan Okun was kind enough to reply to my theory/question as to whether or not the Ansaldo M1934 had the energy to breach the Bismarck's armor for a kill shot, at ranges of 10,000 or 15,000 yards.  As we know, the British were unable to do this from 2,500 yards with the Rodney, and King George V.  The following is his answer, with the occasional notation by myself, and my conclusion:

Dear Mr. XXXXXXXXX,

 

Looking at your BISMARCK diagram, the 110mm (4.33") sloped Wh-armor (= US WWII STS in quality) deck is at 60 degrees sloped inboard from the vertical at this narrowed ship width abreast Turret BRUNO -- usually 68 degrees amidships where the ship was wider -- and the 320mm (12.6") KC n/A belt+50mm (1.96") cement+~20mm (0.787") Schiffbaustahl III hull (= ~16.5mm (0.65") Wh-armor) waterline belt (KC n/A is slightly inferior in quality to US early-WWII Thick Chill Class "A" armor -- my Standard Armor -- but it has a thinner face layer for reduced scaling effects, which more than compensates against large-caliber shells, like the 15" shell we are considering here) is sloped outboard at 10 degrees (close enough).  The Italian 381mm (15") M1934 APC projectile weighed (average) 885 kg (1951 lb, slightly more than the British WWII 15" Mk 17B -- Italian APC shells were originally based on British pre-WWI APC ammo and kept the general design concept of the heavy shell, though fired at a significantly higher MV than the British did these heavy shells).  I cannot find detailed data on the projectile AP cap and windscreen weights, so I am going to assume the AP cap weighs 12% of the projectile total weight (234 lb or 106.2 kg) and the windscreen weighs 3% (58.5 lb or 26.5 kg), making the bare-nosed body weight 752.3 kg (1658.5 lb).    The MV was reduced from the original value of 870 m/s (2954 ft/s) to reduce excessive barrel wear problems to 850 m/s (2789 ft/s), which I assume is what you are using.

 

Here is my only departure from Mr. Okun's data; I was, in fact, using the 870 m/s quoted by Ansaldo.  The difference is not huge, but let us keep this in mind.  Also, I trust Mr. Okun's extrapolations for whatever exact data he did not have.

 

I will be using my latest penetration computer programs:  FACEHARD Version 7.8 FACEHD78 (face-hardened armor, here KC n/A plus hull backing layers) and HCWCALC Version 3 HCWCLCR3 (homogeneous armor, here Wh and Ww).

 

Using FACEHD78, at 10,000 yards the APC shell hits the belt just above the waterline at  ~701 m/s (2300 ft/s) at an angle of fall of ~4.9 degrees -- estimate from the range table value at 10,000 m (10, 936 yards) of 687 m/s (2284 ft/s) and an angle of fall of 5 degrees.  This gives an obliquity angle of 10+4.9 degrees = 14.9 degrees on the KC n/A+backing belt, with no horizontal component, assuming BISMARCK's Target Angle is ~87 degrees (moving slightly toward the Italian BB) to take the curvature of BISMARCK as it narrows toward the bow into account.  Running the shell data, armor data, striking velocity, and impact obliquity into FACEHARD ARMOR SELECTION #10 (Krupp KC n/A, which also includes its WWII special-purpose thin-plate KNC and Thin-Chill Armored Tube KC due to lack of any test data to the contrary) and ITALIAN PROJECTILE SELECTION #12 (assumes a direct upgrade of WWI-era post-Jutland British Mk 5A APC design, not the later deformable British APC actually used in WWII, which may be wrong, but no contrary data)., the NBL for complete penetration is 390.1 m/s (1280 ft/s), the shell's body (AP cap and windscreen are now gone) is now moving forward at 467.6 m/s (1534 ft/s) with no noticeable damage and no yaw or wobble (other than the usual tiny nutation -- ignored here -- due to the shell's spin through the air) and, since the obliquity was under 15 degrees, no deflection, either, so the projectile is still moving downward at ~4.9 degrees toward the sloped 110mm Wh deck plate.

 

For those not well-versed in ballistics, Mr. Okun has concluded that the shell has defeated the outer layer of armor, is de-capped, but is still in good structural integrity.  It is now moving toward the sloped armor.

 

At 15,000 yards the APC shell hits the belt just above the waterline at  ~625.7 m/s (2053 ft/s) at an angle of fall of ~8 degrees -- estimate from the range table value at 15,000 m (16, 404 yards) of 620 m/s (2034 ft/s) and an angle of fall of 8.7 degrees.  This gives an obliquity angle of 10+8 degrees = 18 degrees on the KC n/A+backing belt, with no horizontal component, as above.  Running the data, armor data, striking velocity, and impact obliquity into FACEHARD ARMOR SELECTION #10 again, and ITALIAN PROJECTILE SELECTION #12 again, the NBL for complete penetration is 390.1 m/s (1324 ft/s), the shell's body is now moving forward at 381 m/s (1250 ft/s) with no noticeable damage and no yaw or wobble and an upward deflection of 0.88 degrees, so the projectile is moving downward at ~7.12 degrees toward the sloped 110mm Wh deck plate.

 

Same as at 10,000 yards.

 

Note that very large chunks of belt armor have been thrown out of the plate back as the face and anything behind it are cracked out and pushed through the plate ahead of the projectile and at an equal or even higher speed.  These will ricochet off of the 110mm sloped deck and tear up the unarmored internal hull above this deck, which is two decks high to the weather deck, since the magazine roof 90mm (3.54") Wh flat main armored deck, from which the sloped deck's top edge is attached, is only slightly above the waterline.  This loss of such a large volume of protected reserve buoyancy across the entire ship width and probably at least two average compartments or even more in length parallel to the ship centerline directly behind the hole in the belt means that just because a shell does not penetrate the sloped deck and is deflected upward by the sloped deck, the ship still pays a heavy penalty for a shell penetration of the belt or, even worse, for a plunging fire penetration of the thin upper belt or weather deck.

 

Now the bare-nosed, medium-length-blunt-point 1658.5-lb projectile body hits the 4.33" Wh sloped deck at 4.9+60 = 64.9 degrees at 10,000 yards or at 7.12+60 = 67.12 degrees at 15,000 yards, going 1534 ft/s or 1250 ft/s, respectively.  Switching to HCWCLCR3, we now input the respective values and we get:

 

                1)  The 10,000-yard NBL is 1560 ft/sec, 26 ft/sec above the striking velocity, so with even a slight variation in plate quality or striking velocity or obliquity, a complete penetration is possible, but the remaining velocity might not be enough to penetrate the vertical, downward-dropping 50mm (1.96") Ww-steel (Krupp's US Navy WWII HTS replacement for such things; roughly 0.85 times its Wh equivalent quality = ~1.67" Wh) anti-torpedo "holding" bulkhead located at the joint of the sloped and flat decks.  Let us see.  Since much of the sloped plate's resistance is due to its high angle causing glancing effects and not in actually stopping the shell motion, if a penetration does occur (adding 26 ft/s to the projectile speed here), we would get ~216.4 m/s (710 ft/s) Remaining Velocity and a downward deflection of 12.1 degrees, so the vertical Ww plate would be hit at an obliquity of 4.9+12.1 = 17 degrees, well above the 70.7 m/s (232 ft/s) NBL for that plate.  However, the fuze delay of the projectile must be over 0.035 second to allow the entire average distance from the belt through the Ww plate going at the Remaining Velocities given above before the fuze causes the shell to detonate.  Since the British used, after Jutland, a 0.025-second delay (taken from the nominal delay used by the German Krupp poorly-designed delay-action fuzes they studied after that battle, and, to my knowledge, kept that delay from then on), it is possible that the Italians kept that delay too, though the German and US 0.035-second design time (0.033-second for the WWII US Mk 21 BDF when actually tested) might have been used (only the Japanese, due to their underwater-hit diving Type 88 and Type 91/1 APC projectiles developed starting in the late 1920s, used much longer delays than this -- 0.2-0.4 second in the battleship-sized shells -- to my knowledge).  If the 0.025-second delay was retained from late-WWI or just after WWI, depending on when the Italians added a fuze delay to their ammunition, the shell is very unlikely to make it through the Ww plate before detonating, which might throw some fragments through that plate, but unless the fuze is a dud or fails to properly detonate the shell, in which case large-sized chunks of shell would hit and probably penetrate that plate, the damage behind the Ww plate would be minimal (a British 14" APC shell actually properly detonated due to fuze action just as it hit this Ww plate in the battle where the HOOD was sunk and just caused some leaks with minimal damage behind that plate, due to the shell being reduced to small-to-medium-sized fragments).  If the delay was 0.035-second or thereabouts, then the chance of penetrating the Ww plate is about 50/50 with the typical spread of delay values of a properly-functioning base fuze.  Therefore, there is a less-than-50/50 chance of the Italian 15" shell penetrating all three plates and/or detonating properly behind the final Ww plate; usually the damage would be minimal unless the fuze fails and the entire projectile or large-size chunks of it tear through that plate.

 

This is possibly the most direct statement that can be made about the possibility of the event;  the critical value of exactly when the fuze detonates the shell, will determine which way the results will go.

 

                2)  At 15,000 yards, the sloped plate requires a striking velocity of 518.2 m/s (1700 ft/s) to penetrate it with this projectile at 67.12-degree obliquity, way above the actual 1250 ft/s striking velocity, so no penetration is possible.  The shell merely skips off the plate, perhaps with some base damage, and, unless the fuze fails, blows up high-order in the upper hull a few feet inboard of the sloped deck inner edge, wrecking anything nearby, but not much far away, other than what the plate plug does as it flies across the ship width.

 

As to the non-magazine spaces near Turret BRUNO, but under the flat 90mm Wh main armor deck, they are completely safe at 15,000 yards through the belt armor, but have some possibility, though less than 50/50 in any event, of the shell or large chunks of it, making it through all of the armor layers to reach those spaces.  If the designed fuze delay is closer to the 0.025-second British value, the chance of making it entirely through the armor is even worse, especially if the fuzes are reliable (interesting that poor fuzes give better results in this case, isn't it?).

 

I assume that penetration in the 10,000 yard scenario is a given?

 

Nathan Okun

 

 

   I wasn't expecting a "less than 50/50 chance" of the shell achieving a kill shot; as those of you who read my posts know, I was prepared to relegate this to a complete longshot, something akin to how the Bismarck felled the Hood; almost a one in a million, but this doesn't seem to be the case.  Mr. Okun believes that the sloped armor will be defeated by the shell from 10,000 yards, but the final factor lies in just when the fuze detonates the shell.   If it does so later, the M1934 wins the scenario, and the Bismarck takes a magazine hit; if it does so sooner, the Bismarck lives, though with serious damage at the site.   To me, this question is still not incontrovertibly settled, but if we consider Mr. Okun's "..less than 50/50 chance..." of success, for a single hit, and consider it across multiple chances at penetration, as the British had that morning (remember, they were firing for almost two hours), I lean toward the conclusion that Bismarck will, sooner than later, take a lethal hit.  

 

   Returning to my original point, and question to WG, how can this weapon possibly be modeled in a fair manner, if it is known to be so superior to the ordnance that was firing at Bismarck, that particular May 27th, yet is of smaller bore?  It is known to be more powerful than Rodney's 16" rifles, the NC/SD 16"/45 rifles, Germany's 16"/52, and at long ranges, anything else that was ever floated on a capital ship.  Please feel free to correct me, but I believe that one of the diving expeditions that sought Bismarck (Ballard's, possibly?) reported that the armor around the ship's vitals had not been pierced by British shells; yet, here we have an expert on naval ordnance that states that not only would the M1934 have penetrated Bismarck's main armor belt, but it would also have caused significant spalling, resulting in even greater damage than the penetration alone, and gone on to defeat the sloped armor deck, albeit from distances less than 10,000 yards.  I write this because I hope to avoid another "Graf Zeppelin"; the Littorio class had guns that were capable of devastating damage due to their velocity, and shell construction, something that is too often overlooked in ballistics.   While the British 14" shattered against the Bismarck's sloped armor deck WITHOUT piercing the main belt, the M1934's shell would have penetrated both, and possibly remained intact.  I hope that WG will give its customers a "Roma" worthy of her name.

 

Peace

[RipNuN2]

Activating the @dseehafer signal. (I love these discussions and learn so much from them)

 

[Admiral_Franz_von_Hipper]

 

“WG i wantz super op ship”

 

 

 

Sorri komrade, but balans is needed.

[renegadestatuz]

Ships arent put at tier just because of their penetration values. Take Musashi for example, she’s just been added/placed at tier 9. 

[Judge_Doom]

Just a side note to this Bismarck thing and kill shots....I just very recently watched a new program on TV about how the ship sank, a forensics type of show into the sinking of the Bismarck, what they concluded was that the ship was intentionally sunk by the crew of the ship, while it had received substantial damage, it was not enough to actually be the cause of its sinking, this conclusion was achieved through further detailed examination of the wreckage and from surviving crew statements. 

Just wanted to toss that out there, please carry on, I too do enjoy these types of threads with all the calculations and summations...its all food for thought.

[Doomlock]

1 minute ago, Judge_Doom said:

Just a side note to this Bismarck thing and kill shots....I just very recently watched a new program on TV about how the ship sank, a forensics type of show into the sinking of the Bismarck, what they concluded was that the ship was intentionally sunk by the crew of the ship, while it had received substantial damage, it was not enough to actually be the cause of its sinking, this conclusion was achieved through further detailed examination of the wreckage and from surviving crew statements. 

It is widely known that the Bismarck was scuttled by her crew and not sunk by the British forces that day. In fact it would have taken even more shells and torpedoes to take her down.

[Doomlock]

OP I appreciate the well done post, however I would like to go and critique.

 

Quote

1). Returning to my original point, and question to WG, how can this weapon possibly be modeled in a fair manner, if it is known to be so superior to the ordnance that was firing at Bismarck, that particular May 27th, yet is of smaller bore? 

 

2). It is known to be more powerful than Rodney's 16" rifles, the NC/SD 16"/45 rifles, Germany's 16"/52, and at long ranges, anything else that was ever floated on a capital ship. 

 

3). Please feel free to correct me, but I believe that one of the diving expeditions that sought Bismarck (Ballard's, possibly?) reported that the armor around the ship's vitals had not been pierced by British shells; yet, here we have an expert on naval ordnance that states that not only would the M1934 have penetrated Bismarck's main armor belt, but it would also have caused significant spalling, resulting in even greater damage than the penetration alone, and gone on to defeat the sloped armor deck, albeit from distances less than 10,000 yards.

 

4). I write this because I hope to avoid another "Graf Zeppelin"; the Littorio class had guns that were capable of devastating damage due to their velocity, and shell construction, something that is too often overlooked in ballistics.   While the British 14" shattered against the Bismarck's sloped armor deck WITHOUT piercing the main belt, the M1934's shell would have penetrated both, and possibly remained intact.  I hope that WG will give its customers a "Roma" worthy of her name.

1). The weapon itself does not define tier. The ship as a whole is the defining factor, AA, tonnage, guns, armor, speed, etc. It has many aspects to balance, not simply penetration. Secondly the M1934 gun was smaller than Rodney's guns, but larger than KGV's gun.

 

2). The British 16" guns are known to be terrible. It has extremely similar characteristics to the 14" guns aboard KGV. As for the 16"/45 of the NC/SD, it is a very good gun, but it was a bit old at the time. The 16"/50 Mark 7 is identical to the stats given by the M1934. The M1934 had to have a 850m/s shell velocity to achieve the same pen and performance as the Mark 7 firing the Mark 8 shell. As for the German gun, it was never fielded, and never used, so it doesn't really count. Yamato's guns, and Iowa's guns have similar performance at long range as M1934. The best gun ever floated on a capital ship has been stated to be the 16"/50 Mark 7.

 

3). Yes, none of the shells pierced the vitals. That was the whole point of what dseehafer said, no ship could do that and pen her magazines to cause catastrophic damage. Ok..and? This is very hypothetical, even as said by Mr. Okun himself, as he had to assume a few values as well.

 

4). This would never be something like what happened with GZ. That was an unfinished ship, with a terrible loadout, that was panned by all. This argument, saying the guns will not have proper justice and modeling if she is T8, which has been widely said to be the tier she should be, is foolhardy. Shell damage is calculated by shell weight and mass, not by velocity and construction, thus, her damage would be similar to the 15"/45 caliber guns on Bismarck and Tirpitz. 

 

WG will give us a Roma worthy of her place at T8, not shoehorned into 9 on one small factor.

Fair winds and following seas captain! 

[BaryOnyxx]

1 hour ago, Doomlock said:

 

 

1 hour ago, Doomlock said:

This argument, saying the guns will not have proper justice and modeling if she is T8, which has been widely said to be the tier she should be, is foolhardy. Shell damage is calculated by shell weight and mass, not by velocity and construction, thus, her damage would be similar to the 15"/45 caliber guns on Bismarck and Tirpitz. 

 

   I regret that you consider my thoughts on the modeling o the Roma's guns to be "foolhardy", but then again , this is America, and we do practice free speech.

 

   If WG patterns the Roma's guns after the Bismarck's units because they had the same bore, it will be akin to modelling the Hood's resistance to battle damage after the Bismarck's, just because it had approximately the same displacement as the Bismarck.  In both cases, there was no comparison between the two values.

 

   I apologize that I can't take the discussion further at this point, as it's 2:22 a.m, and I have work tomorrow.  Good night to all!

[dseehafer]

Very Interesting! I am surprised that Mr. Okun contacted you back with such a detailed answer!

 

I'm not going to argue with man of his caliber but I will say this, If a Bismarck has let a Littlorio class close to within 10km it is probably already tactically defeated, and therefore a citadel hit would just be the icing on the cake. Or, alternatively, the Bismarck class has already tactically defeated the Littorio and is closing in for the finishing blows and Littorio cannot effectively return fire to score said citadel hit. My point is, if the ships get to the point where they are fighting within 10km, one of them is probably already defeated (as was the case with Bismarck's final battle).

 

Again, very interesting! :)

[SinqueScheiDeMona]

If you are going to reference a ship make it the lead ship Littorio. 

[renegadestatuz]

2 hours ago, SparvieroVV said:

If you are going to reference a ship make it the lead ship Littorio. 

And why exactly does it have to be the lead ship?

[Doomlock]

8 hours ago, Rotten_Fish said:

If WG patterns the Roma's guns after the Bismarck's units because they had the same bore, it will be akin to modelling the Hood's resistance to battle damage after the Bismarck's, just because it had approximately the same displacement as the Bismarck.  In both cases, there was no comparison between the two values.

Now you have just taken what I said out of context and way out of proportion. 

 

Shell damage is determined by weight, and size of shell. Penetration is determined by weight, Krupp, and velocity. 

 

So, in terms of penetration, you can expect it to work very closely to how Bismarck's/Monarch's guns work in game.

 

Monarch is the closest contemporary to Roma's guns in terms of shell weight, and shell velocity. So I'll go with that. Based off of Monarch, I'd put Roma's gun damage at 11,900 max. Her pen would be similar to the US 16" Mark 8 shell fired by NC and Bama. As for her range, reload, and accuracy? I have no idea.

 

For all listed above and the rest of the ship's stats, she is a firm T8.

 

Fair winds and following season captain. 

[BaryOnyxx]

50 minutes ago, Doomlock said:

Now you have just taken what I said out of context and way out of proportion. 

 

Shell damage is determined by weight, and size of shell. Penetration is determined by weight, Krupp, and velocity. 

 

So, in terms of penetration, you can expect it to work very closely to how Bismarck's/Monarch's guns work in game.

 

Monarch is the closest contemporary to Roma's guns in terms of shell weight, and shell velocity. So I'll go with that. Based off of Monarch, I'd put Roma's gun damage at 11,900 max. Her pen would be similar to the US 16" Mark 8 shell fired by NC and Bama. As for her range, reload, and accuracy? I have no idea.

 

For all listed above and the rest of the ship's stats, she is a firm T8.

 

Fair winds and following season captain. 

I certainly did not intend to take your comments out of context, so I will try to differentiate between the game, and reality.

 

In reality, a shell's ability to do damage to its target is based *mainly* on two variables; 1) kinetic energy, and 2) structural integrity.  KE provides the energy (work) necessary to defeat the armor, PROVIDING that the shell can stay together long enough to breach it.  Mr Okun, a naval ordnance designer, pointed out that the British 14" shattered when it struck the Bismarck's sloped armor, yet he clearly stated that the M1934 would have penetrated both the belt, and sloped armor in the Bismarck, and stayed in one piece.  He took into account the type of metal in each case, striking velocity, angle, etc., when he reached his conclusion.

Regarding the penetrative, and hence, damaging ability of the M1934, the USN empirical equation clearly puts it in the top 3 at the muzzle, tied for first place past 15k yards, and absolutely first past 28k yards.  No other gun ever floated can shoot as far, and the Littorio proved that it is accurate enough to repeatedly splinter fleeing destroyers at 35,000 yards - an incredible accomplishment without radar.  Further, both Dulin and Garzke, and Mr. Okun have stated that a shell with the M1934's architecture does tremendous damage just from its spalling effects upon impact, separate from its penetrative damage.  

 

As far as the game is concerned, what I have been trying to say is that since the Roma's guns were inordinately good performers in real life, their representation in the game will most likely be inferior to what they could have done in an actual battle.  If I have been unclear on this matter, I apologize.

 

Peace

[BaryOnyxx]

5 hours ago, dseehafer said:

Very Interesting! I am surprised that Mr. Okun contacted you back with such a detailed answer!

 

I'm not going to argue with man of his caliber but I will say this, If a Bismarck has let a Littlorio class close to within 10km it is probably already tactically defeated, and therefore a citadel hit would just be the icing on the cake. Or, alternatively, the Bismarck class has already tactically defeated the Littorio and is closing in for the finishing blows and Littorio cannot effectively return fire to score said citadel hit. My point is, if the ships get to the point where they are fighting within 10km, one of them is probably already defeated (as was the case with Bismarck's final battle).

 

Again, very interesting! :)

 

LOL!   Ok my friend, you are very subtly changing the nature of our discussion!  Our original question was whether or not the Littorio could have delivered a kill shot to Bismarck from 10-15k yards, and Mr. Okun's opinion seems to be that its chances were somewhat less than 50/50.  If we are going to consider an all-out Littorio vs. Bismarck battle, I must respectfully demur, as there are simply too many variables to consider!  Feel free to initiate a thread on the question, as I would be very interested in following it!

 

Peace!

[Doomlock]

34 minutes ago, Rotten_Fish said:

As far as the game is concerned, what I have been trying to say is that since the Roma's guns were inordinately good performers in real life, their representation in the game will most likely be inferior to what they could have done in an actual battle.  If I have been unclear on this matter, I apologize.

I will not argue with reality, yes the guns performed very well, and were capable of ranges no other gun could hit. In fact as I stated, they performed on the level of the US 16"/50 Mark 7 and the 46cm/45 of Yamato, both some of the best naval rifles ever built. Nor am I gonna argue with Mr. Okun, I have neither the smarts, nor the skills to remotely try.

 

However for in game purposes, the M1934 will translate to have very good penetration, indeed on the level of Iowa and Yamato, and will have a high velocity, but will have equivalent damage to Monarch's 15" shells due to the reasons I have stated earlier. 

 

Roma will likely be known for high velocity, high penetration guns, and perhaps long range (soft state that can change). But maybe suffer from a long reload cycle, or accuracy.

 

I may have gone slightly overboard with my accusations as well. For that, I also apologize.

 

Fair winds and following season captain. 

[WolfofWarship]

Very interesting discussion guys! Thanks for sharing!

[BaryOnyxx]

YW!  Check out Nathan's correction to his original calculations: it turns out the PK from 10k yards was >90%, and about 50% from 15k.