Questions about armour

[seawolf]

Apr 18, 2020 9:28:15 GMT -6 Antediluvian Monster said:

Apr 18, 2020 7:01:57 GMT -6 corsair1 said:

I have done som study after my last answer and I agree with you on that, And The Iowa also have a decapping belt so that might be the reason for the internal belt.
If the belt is simply bolted to the side, Why is it not possible to change the belt armour in a refit. That would be a nice addition to the game

Historically it was possible, if very rare, to replace the armoured belt with entirely new one. Renown and Repulse had this done to them. I'd guess the rarity of it is why it's not possible in the game.

The internal belt on Iowa and South Dakota was essentially a weight saving measure. The inclined belt would have cut too much from the beam on these designs otherwise so they resolved the issue by putting the ship's sides beyond the belt. The splinter protection to the sides was given so that just anything wouldn't flood the area between the sides and the belt. Unlike Italians and Germans, I don't think Americans did particular research on decapping until WW2 so this was probably not the intent at least.

Several other ships had their entire belts removed and then added back on.  Hiei comes to mind.

[christian]

Apr 18, 2020 11:36:53 GMT -6 rimbecano said:

Apr 18, 2020 4:27:10 GMT -6 christian said:

naval penetration tests are not done like tank armor where the americans required it to pen 50% of the time and the germans 75% of the time if i remember right(though thats completely off memory since i dont look into tanks as much as ships so take this with a few grains of salt)

naval penetration tests were done so that the stated penetration at x range against x armor would ALWAYS (with the exception of rare outliers) penetrate with the bursting charge intact 
this is the EFF or effective limit because there is no practical reason to have anything else unlike with tanks follow up shots were far harder to achieve and the shape of the tank usually meant it did not hit a directly flat surface plate and had a bit of variability in the penetration and even non penetrating hits could do serious damage to a tank

...

www.navweaps.com/index_nathan/os696BalSpecs.php

here is also an article by nathan okun on american shell testing which states the following

In all projectile tests against armor, projectile must completely penetrate the armor plate specified at the obliquity and striking velocity specified with no damage that would reduce the explosive effectiveness of the projectile after penetration (no cracking into or breakage open of the explosive cavity, the base plug still seated tightly, and the fuze still functional - this last was determined in these fuze-less tests by examining the distortion/cracking/breakage of the explosive cavity, the base plug still seated tightly, and the fuze still functional - this last was determined in these fuze-less tests by examining the distortion/cracking/breakage of the lower projectile body and base plug after the test).

That Okun article does not support your position, because it deals with an entirely different type of testing than would be used to create penetration tables. The Okun article describes testing of shells whose penetration characteristics are already known, in order to verify that a given batch is up to spec. In this case you take a few shells from each batch and fire them at something that you know will be penetrated by properly manufactured shells. If you don't get full penetration, you throw the batch out. The Okun article states that one failure was allowed out of three shells selected from a batch for testing, which would be penetration 66% of the time if these were tests to create penetration tables, rather than quality control tests, so even if this *were* the type of testing used to create penetration tables, it wouldn't support the position that the stated penetration was against the maximum thickness of armor that would always be penetrated.

the same cannot be said with warships non exploding and penetrating hits cause basically no damage at all to the battleship 

159 men that served aboard SMS Seydlitz at Dogger Bank would take issue with that allegation. In that case, the shell failed to enter the barbette, but *did* hole the armor and *did* explode, and this caused a propellant fire that burned out both rear turrets and killed their entire crews.

159 men that served aboard SMS Seydlitz at Dogger Bank would take issue with that allegation. In that case, the shell failed to enter the barbette, but *did* hole the armor and *did* explode, and this caused a propellant fire that burned out both rear turrets and killed their entire crews.

this is not exactly a surprise since even non penetrating hits could cause magazine explosions by shrapnell  as long as the spall the turret barbette armor and some of the fragments ignite the powder 
probably should have been a bit more clear on this what i wrote was mainly for the belt armor


also the story would have looked a whole lot differently if the projectile had penetrated and instantly blown up all the powder instead of a propellant fire which could have spread to the shell magazines but was stopped by flooding said magazines to avoid the ship becoming a giant fireball
had it not been an ammunition fire but an instant explosion it might not have given the crew enough time to flood said magazine and the ship would have been lost


same happens with tanks while a 100mm AP projectile might not penetrate it can spall ignite the powder and burn out the tank 

though it is alot more common for it to happen in tanks because the tank is so cramped and the casings so close to the sides of the tank and eachother


turret/barbette hits on a battleship are some of the only areas where a partial penetration can cause significant damage

you actually dont even need a penetrating hit a hit to the barrel or between the turret and barbette will destroy a gun barrel or jam the turret most likely permanently basically putting said turret out of action

That Okun article does not support your position, because it deals with an entirely different type of testing than would be used to create penetration tables. The Okun article describes testing of shells whose penetration characteristics are already known, in order to verify that a given batch is up to spec. In this case you take a few shells from each batch and fire them at something that you know will be penetrated by properly manufactured shells. If you don't get full penetration, you throw the batch out. The Okun article states that one failure was allowed out of three shells selected from a batch for testing, which would be penetration 66% of the time if these were tests to create penetration tables, rather than quality control tests, so even if this *were* the type of testing used to create penetration tables, it wouldn't support the position that the stated penetration was against the maximum thickness of armor that would always be penetrated.

the okun tables are made by facehard yet that dosent change the fact that the chances of a projectile making it through the armor with an intact fuse and able to explode BEYOND the partial penetrating limit (which is even higher than the complete penetration limit) is not realistic and neither is a 16 inch projectile that can somehow pen 4.8 inches more than it should and still be in a condition to deal full damage 

also yeah my mistake 1 out of 3 shells was allowed to fail so its a 33% chance for the projectile to under perform

though this actually means the shell most likely has an even LESSER chance to over perform than it would if it penetrated 100% of the time as it only penetrated 66% of the time which must mean the projectile has problems penetrating and cant breeze through as if it always penetrated this also means a thicker plate would give said projectile even more trouble

(going from the 1 out of 3 shells allowed to fail as we dont know how many actually failed on average if exactly 33% failed or 20% did or 2%)


and while projectiles should over perform and under perform (some nations more than others hint hint Italy and your HORRIBLE quality control) the severity of which they do right now rivals 1905 tsushima quality control where every time you fired your guns it was a dice roll of whether you had a +20% armor penetration projectile or -20% one

i doubt that by ww2 with the quality control SOME NATIONS (HINT HINT NOT ITALY) had put in place the total performance variance was more than 10-20% (-5 to +5%) 

this can be seen with the muzzle velocity variance on the american 16 inch gun

When the smokeless propellants (SP) were freshly made during World War II, MV varied no more than +/- 10 fps (3 mps) shot to shot and often no worse than +/- 5 fps shot to shot. As SP will degrade over time, a few years later during the Korean deployments MV varied about +/- 14 fps (4.3 mps) and during Vietnam about +/- 23 fps (7 mps). By the time of the 1980s deployments, shot to shot variation was about +/- 32 fps (9.8 mps). This large variation was a primary contributor to USS New Jersey's poor shooting off Lebanon in 1984. As a result, the NSWC Dhalgren facility and USS Iowa were tasked with improving performance. Old D839 and D846 propellant lots were remixed and proved to bring variation back within the +/- 10 fps requirement.

www.navweaps.com/Weapons/WNUS_16-50_mk7.php#ammonote13


sometimes you get a belt hit where you have 20% more armor than needed to protect your ship but it penetrates and takes out a turret or destroys your engines


ive had a 26 inch turret flash fired by a 16 inch gun before at 8000 yards (it was listed as penetration by the hit which took out the turret and flashed it so it did pen)
the 16 inch gun at that range had less than 21 inches of penetration

[dorn]

RTW simulates a lot of things which was real as:
- weaknesses in protection system (eg. Scharnhorst hit in machinery)
- citadel is not protected in whole manner (funnels etc.)
- belt and TDS is not uniform (the width is not same for whole citadel making TDS usually weaker at the end, belt can be sloped)

etc. 

All together does mean that if 16" is stated as needed penetration, it does not mean that it is in every spot on vertical protection of citadel.

Always one thing is theoretical protection, the second thing is real protection which was again and again proved that is completely different things. Sometimes it is stated that some weapon platforms (ships) has much better protection, usually because they were never battle tested. 
This is simulated in RTW however you cannot simulate this by penetration formula. Quite usually weakness is found after it shows in battle not before. But because there is no awareness of weakness in system does not mean there is none. 

[christian]

Apr 18, 2020 16:07:58 GMT -6 dorn said:

RTW simulates a lot of things which was real as:
- weaknesses in protection system (eg. Scharnhorst hit in machinery)
- citadel is not protected in whole manner (funnels etc.)
- belt and TDS is not uniform (the width is not same for whole citadel making TDS usually weaker at the end, belt can be sloped)

etc. 

All together does mean that if 16" is stated as needed penetration, it does not mean that it is in every spot on vertical protection of citadel.

Always one thing is theoretical protection, the second thing is real protection which was again and again proved that is completely different things. Sometimes it is stated that some weapon platforms (ships) has much better protection, usually because they were never battle tested. 
This is simulated in RTW however you cannot simulate this by penetration formula. Quite usually weakness is found after it shows in battle not before. But because there is no awareness of weakness in system does not mean there is none. 

wait so does this mean you can design a ship which has a very good protection system 

but a ship with the exact same protection but is a diffrent design could have a very bad one

and the very bad one despite having the exact same armor and torpedo defence and so on would have a higher chance of being hit in a "weakspot" and being penetrated despite it on paper being impossible

[dorn]

Apr 18, 2020 17:15:31 GMT -6 christian said:

Apr 18, 2020 16:07:58 GMT -6 dorn said:

RTW simulates a lot of things which was real as:
- weaknesses in protection system (eg. Scharnhorst hit in machinery)
- citadel is not protected in whole manner (funnels etc.)
- belt and TDS is not uniform (the width is not same for whole citadel making TDS usually weaker at the end, belt can be sloped)

etc. 

All together does mean that if 16" is stated as needed penetration, it does not mean that it is in every spot on vertical protection of citadel.

Always one thing is theoretical protection, the second thing is real protection which was again and again proved that is completely different things. Sometimes it is stated that some weapon platforms (ships) has much better protection, usually because they were never battle tested. 
This is simulated in RTW however you cannot simulate this by penetration formula. Quite usually weakness is found after it shows in battle not before. But because there is no awareness of weakness in system does not mean there is none. 

wait so does this mean you can design a ship which has a very good protection system 

but a ship with the exact same protection but is a diffrent design could have a very bad one

and the very bad one despite having the exact same armor and torpedo defence and so on would have a higher chance of being hit in a "weakspot" and being penetrated despite it on paper being impossible

It is like this. Or do you have any explanation why ships with weak spots exists?

Now you have that knowledge, it is quite a handsight that was not available at that time.

South Dakota has worse TDS than previous class. How can somebody build ship which has something worse if he does not it?

[christian]

Apr 19, 2020 2:11:21 GMT -6 dorn said:

Apr 18, 2020 17:15:31 GMT -6 christian said:

wait so does this mean you can design a ship which has a very good protection system 

but a ship with the exact same protection but is a diffrent design could have a very bad one

and the very bad one despite having the exact same armor and torpedo defence and so on would have a higher chance of being hit in a "weakspot" and being penetrated despite it on paper being impossible

It is like this. Or do you have any explanation why ships with weak spots exists?

Now you have that knowledge, it is quite a handsight that was not available at that time.

South Dakota has worse TDS than previous class. How can somebody build ship which has something worse if he does not it?

i thought ship weak spots were equal no matter what and not based on a a random dice roll between ships aka 2 ships with the same armor scheme would have the same chance to have a weak spot in the armor 


how does hidden flaws effect this does it have an effect outside of flash fires ?

It is like this. Or do you have any explanation why ships with weak spots exists?

do you have any source from the devs that it works like this ?





(and the above thing i said was not in relation to real life where some designs have obvious weaknesses which are obvious in hindsight or have an actually good reason behind them i was referring to IN GAME)

South Dakota has worse TDS than previous class. How can somebody build ship which has something worse if he does not it?

the tds on the south dakota was worse than some american dreadnoughts due to having the armored belt extend further down 

i.imgur.com/666TwME.png


which is not really a surprise since certain pre dreadnoughts had some of the best torpedo protection in the world 
www.navweaps.com/index_tech/tech-047.php

lh3.googleusercontent.com/proxy/VS-DRJ-JSVinXOdotTNciVvDfxldFm7rW5_JInn86YkY7l0Ww_5v3ESZj3uKNWFYYGFVs3pRARmUF5pXFEQTJYAu2BD7lq46SgtrP0SczsZPOpurmLrfkZPrVoVL9Y4

uss tennasse 

[corsair1]

Apr 19, 2020 2:11:21 GMT -6 dorn said:

Apr 18, 2020 17:15:31 GMT -6 christian said:

wait so does this mean you can design a ship which has a very good protection system 

but a ship with the exact same protection but is a diffrent design could have a very bad one

and the very bad one despite having the exact same armor and torpedo defence and so on would have a higher chance of being hit in a "weakspot" and being penetrated despite it on paper being impossible

It is like this. Or do you have any explanation why ships with weak spots exists?

Now you have that knowledge, it is quite a handsight that was not available at that time.

South Dakota has worse TDS than previous class. How can somebody build ship which has something worse if he does not it?

This is actually realistic, the only thing i really do when designing a ship is ordering specs. the detailed design is made during the x months design study.
So to sum it up:
Reason for seing shells penetrating more than they should is simply weakspots from the design study period, poor problem solving and bad work quality from dockyard workers and engineers.
Currently the game does not model for irreparable damage (would be a nice addition though)

One thing I haven't gotten any answers to, is how do i identify hits from diving shells hitting below the belt. I thought "torpedo flat hit*" ment hit from diving shell, but if I don't have submerged torpedoes I shouldn't have a torpedo flat should I? 

[wlbjork]

Yes, we do have a statement that there is a percentage modifier applied to the penetration rate when armour is hit - this can be positive or negative.

As far as I know, the game does not roll a precise location of the hit (e.g. 6" above waterline dead centre of belt), simply a generic location.

The penetration "roll" can then be considered all the various factors that have an effect on whether a round penetrates or not - angle of incidence, thickness of armour at point struck and so on

[christian]

Apr 19, 2020 7:11:08 GMT -6 corsair1 said:

Apr 19, 2020 2:11:21 GMT -6 dorn said:

It is like this. Or do you have any explanation why ships with weak spots exists?

Now you have that knowledge, it is quite a handsight that was not available at that time.

South Dakota has worse TDS than previous class. How can somebody build ship which has something worse if he does not it?

This is actually realistic, the only thing i really do when designing a ship is ordering specs. the detailed design is made during the x months design study.
So to sum it up:
Reason for seing shells penetrating more than they should is simply weakspots from the design study period, poor problem solving and bad work quality from dockyard workers and engineers.
Currently the game does not model for irreparable damage (would be a nice addition though)

One thing I haven't gotten any answers to, is how do i identify hits from diving shells hitting below the belt. I thought "torpedo flat hit*" ment hit from diving shell, but if I don't have submerged torpedoes I shouldn't have a torpedo flat should I? 

its a shame that ships return after peak condition after being repaired where in real life they often still had a slightly weakened structure or the shells holes were patched up and weaker than before (mostly for non belt armor as previously stated belt was in modules which could be replaced)

[secondcomingofzeno]

Apr 18, 2020 7:01:57 GMT -6 corsair1 said:

Apr 18, 2020 6:41:46 GMT -6 Antediluvian Monster said:

Being more difficult to repair was recognized weakness in Iowa's and South Dakota's belt design. Such design is an exception rather than rule though. Even later in the period Yamato, North Carolina, Montana, King George V, Bismarck etc. did not have internal belt. Littoro had a kinda internal belt, but it was manufactured in modules that were bolted on the ship's sides after launch just like regular belt.

I have done som study after my last answer and I agree with you on that, And The Iowa also have a decapping belt so that might be the reason for the internal belt.
If the belt is simply bolted to the side, Why is it not possible to change the belt armour in a refit. That would be a nice addition to the game

The only BB to have a decapping belt was the Italian Littorio class.

Iowa's external plating was for structural, hydrodynamic and anti-flood reasons.

[christian]

Apr 20, 2020 4:22:32 GMT -6 secondcomingofzeno said:

Apr 18, 2020 7:01:57 GMT -6 corsair1 said:

I have done som study after my last answer and I agree with you on that, And The Iowa also have a decapping belt so that might be the reason for the internal belt.
If the belt is simply bolted to the side, Why is it not possible to change the belt armour in a refit. That would be a nice addition to the game

The only BB to have a decapping belt was the Italian Littorio class.

Iowa's external plating was for structural, hydrodynamic and anti-flood reasons.

even then i think littorios decapping belt while thick enough did not have a big enough space between the decap belt and main belt (250mm air if i remember right) 

discovery.nationalarchives.gov.uk/details/r/C518936

only really 2 relevant pages about decapping there 

Attachments:

[secondcomingofzeno]

Apr 20, 2020 7:09:43 GMT -6 christian said:

Apr 20, 2020 4:22:32 GMT -6 secondcomingofzeno said:

The only BB to have a decapping belt was the Italian Littorio class.

Iowa's external plating was for structural, hydrodynamic and anti-flood reasons.

even then i think littorios decapping belt while thick enough did not have a big enough space between the decap belt and main belt (250mm air if i remember right) 

discovery.nationalarchives.gov.uk/details/r/C518936

only really 2 relevant pages about decapping there 

The gap was filled with cement foam, this was calculated to enable decapping for the shells expected to be up against. ;D

[christian]

Apr 20, 2020 9:09:04 GMT -6 secondcomingofzeno said:

Apr 20, 2020 7:09:43 GMT -6 christian said:

even then i think littorios decapping belt while thick enough did not have a big enough space between the decap belt and main belt (250mm air if i remember right) 

discovery.nationalarchives.gov.uk/details/r/C518936

only really 2 relevant pages about decapping there 

The gap was filled with cement foam, this was calculated to enable decapping for the shells expected to be up against. ;D

that might actually have made it work considering the german results

though it depends on how cement foam compares to cement in performance

[secondcomingofzeno]

Apr 21, 2020 6:13:09 GMT -6 christian said:

Apr 20, 2020 9:09:04 GMT -6 secondcomingofzeno said:

The gap was filled with cement foam, this was calculated to enable decapping for the shells expected to be up against. ;D

that might actually have made it work considering the german results

though it depends on how cement foam compares to cement in performance

From what I can gather, it worked...Kinda.

They tested scale models with a 320mm gun and it worked, with estimations the fullscale thing would work against a 380mm (15 inch) gun/projectile.

Alternatively they tested the fullscale thing against a higher muzzle velocity 320mm and went 'eh I think it'll work'.

[geroj]

Wait, wait, wait, can we get back to this part "Yes, we do have a statement that there is a percentage modifier applied to the penetration rate when armour is hit - this can be positive or negative." what, how, when? I checked .20d files but I cant find anything there