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The Science and Math behind HE shell penetration?

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Looking at the numbers for damage on some of my ships concerning HE shell penetration, using my Prinz Eugen as an example. 2500 max damage per shell, 8 guns, 51mm penetration capacity.  Assuming no dispersion, I hit what I am aiming at.....What ship and where do I hit him to get 20k damage from one full salvo of HE to get 20k damage? Does damage saturation come into play negating what should be a monster hit?

In most cases I am farming superstructure with HE to get fires.... so I have never really addressed strategic aiming concerning HE. Is it possible to get that kind of raw damage? I know I have blapped DD's for big numbers, but never a 20k shot with HE that I can recall....

Just curious if this is just fantasy or can it be done and how so?

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HE shells perform very differently than AP shells.

  1. They don't lose penetration over distance.
  2. They don't enter the ship at all -- they explode on the first surface they impact.

So that means an HE shell with 51mm of penetration has 51mm of penetration at 2km and 51mm of penetration at 20km.  As they always explode on the first surface they contact, in order to deal damage, the surface they strike must have less armour than their penetration value in order to do damage.

  • If that surface is the ship's citadel, then your Prinz Eugen's shells will do 2,500 damage each.
  • If that surface is an unsaturated part of the ship, then your Prinz Eugen's shells will do 825 damage each.
  • If that surface is a saturated part of the ship, then your Prinz Eugen's shells will do 413 damage each.
  • If that surface is a fully saturated (black) part of the ship, then your Prinz Eugen's shells will do 250 damage each.

You'll note that I said that it's only against the citadel where your shells will do 2,500 damage -- thus if you wanted that big 20,000 volley, all eight are going to have to hit the citadel.  But therein lies the problem -- HE shells never enter the ship, they only explode on the surface.  Thus in order to get that big 20,000 damage volley the three criteria must be met:

  • The ship's citadel must be exposed to the open air.
  • The ship's citadel must have less armour than your HE shells have in penetration.
  • Your shells must all strike this specific area.

This is a very tall order and there are very (VERY) few ships that can take HE citadel hits at all.  A lot of ships have their citadels protected internally so they can't take citadel hits from HE shells at all, regardless of the penetration  Those that do have them externally tend to have in excess of 100mm+ worth of armour protecting them.  It's only really at mid to low tiers where Prinz Eugen's 51mm worth of penetration might be able to land a citadel hit, but these ships aren't found within her Matchmaking.

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15 minutes ago, LittleWhiteMouse said:

HE shells perform very differently than AP shells.

  1. They don't lose penetration over distance.
  2. They don't enter the ship at all -- they explode on the first surface they impact.

So that means an HE shell with 51mm of penetration has 51mm of penetration at 2km and 51mm of penetration at 20km.  As they always explode on the first surface they contact, in order to deal damage, the surface they strike must have less armour than their penetration value in order to do damage.

  • If that surface is the ship's citadel, then your Prinz Eugen's shells will do 2,500 damage each.
  • If that surface is an unsaturated part of the ship, then your Prinz Eugen's shells will do 825 damage each.
  • If that surface is a saturated part of the ship, then your Prinz Eugen's shells will do 413 damage each.
  • If that surface is a fully saturated (black) part of the ship, then your Prinz Eugen's shells will do 250 damage each.

You'll note that I said that it's only against the citadel where your shells will do 2,500 damage -- thus if you wanted that big 20,000 volley, all eight are going to have to hit the citadel.  But therein lies the problem -- HE shells never enter the ship, they only explode on the surface.  Thus in order to get that big 20,000 damage volley the three criteria must be met:

  • The ship's citadel must be exposed to the open air.
  • The ship's citadel must have less armour than your HE shells have in penetration.
  • Your shells must all strike this specific area.

This is a very tall order and there are very (VERY) few ships that can take HE citadel hits at all.  A lot of ships have their citadels protected internally so they can't take citadel hits from HE shells at all, regardless of the penetration  Those that do have them externally tend to have in excess of 100mm+ worth of armour protecting them.  It's only really at mid to low tiers where Prinz Eugen's 51mm worth of penetration might be able to land a citadel hit, but these ships aren't found within her Matchmaking.

TY, in reality, just keep spamming away at superstructure for consistent damage and fires?

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2 minutes ago, Joyous_Vibes said:

TY, in reality, just keep spamming away at superstructure for consistent damage and fires?

Spread your hits out to whatever you can damage so you get those meaty unsaturated hits.  Prinz Eugen's 51mm worth of penetration means that she can hit lots of different areas and score those 825-damage chunks across the bow, stern, superstructure, upper hull and deck of most targets she faces.  When you notice the damage lower a bit, adjust fire to a new section.  Eventually you'll saturate most of the areas but your target should be on low health and/or burning nicely at that stage.

Edited by LittleWhiteMouse
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15 minutes ago, HazeGrayUnderway said:

Damage Saturation! 

npdZWKV.gif

Why you got to spread the love and not focus on one spot!

I kinda miss this old model.  It's gone, for better or worse.  Each of those torpedoes does a minimum of 10% of its damage now under the current system.

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1 hour ago, LittleWhiteMouse said:

 

You'll note that I said that it's only against the citadel where your shells will do 2,500 damage -- thus if you wanted that big 20,000 volley, all eight are going to have to hit the citadel.  But therein lies the problem -- HE shells never enter the ship, they only explode on the surface.  Thus in order to get that big 20,000 damage volley the three criteria must be met:

  • The ship's citadel must be exposed to the open air.
  • The ship's citadel must have less armour than your HE shells have in penetration.
  • Your shells must all strike this specific area.

This is a very tall order and there are very (VERY) few ships that can take HE citadel hits at all.  A lot of ships have their citadels protected internally so they can't take citadel hits from HE shells at all, regardless of the penetration  Those that do have them externally tend to have in excess of 100mm+ worth of armour protecting them.  It's only really at mid to low tiers where Prinz Eugen's 51mm worth of penetration might be able to land a citadel hit, but these ships aren't found within her Matchmaking.

Interesting....even after nearly 7k battles I'm still learning things about game mechanics.  I know I've scored HE citadels with Conquerer on Minotaurs and Smolensks, which other cruisers can be citadeled with HE?

Edited by Call_of_the_Mastodon

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1 hour ago, LittleWhiteMouse said:

HE shells perform very differently than AP shells.

  1. They don't lose penetration over distance.
  2. They don't enter the ship at all -- they explode on the first surface they impact.

So that means an HE shell with 51mm of penetration has 51mm of penetration at 2km and 51mm of penetration at 20km.  As they always explode on the first surface they contact, in order to deal damage, the surface they strike must have less armour than their penetration value in order to do damage.

  • If that surface is the ship's citadel, then your Prinz Eugen's shells will do 2,500 damage each.
  • If that surface is an unsaturated part of the ship, then your Prinz Eugen's shells will do 825 damage each.
  • If that surface is a saturated part of the ship, then your Prinz Eugen's shells will do 413 damage each.
  • If that surface is a fully saturated (black) part of the ship, then your Prinz Eugen's shells will do 250 damage each.

You'll note that I said that it's only against the citadel where your shells will do 2,500 damage -- thus if you wanted that big 20,000 volley, all eight are going to have to hit the citadel.  But therein lies the problem -- HE shells never enter the ship, they only explode on the surface.  Thus in order to get that big 20,000 damage volley the three criteria must be met:

  • The ship's citadel must be exposed to the open air.
  • The ship's citadel must have less armour than your HE shells have in penetration.
  • Your shells must all strike this specific area.

This is a very tall order and there are very (VERY) few ships that can take HE citadel hits at all.  A lot of ships have their citadels protected internally so they can't take citadel hits from HE shells at all, regardless of the penetration  Those that do have them externally tend to have in excess of 100mm+ worth of armour protecting them.  It's only really at mid to low tiers where Prinz Eugen's 51mm worth of penetration might be able to land a citadel hit, but these ships aren't found within her Matchmaking.

Why can destroyers routinely get HE citadel hits on carriers?

Why does my Drake get HE citadel hits on carriers?

BOTH INSTANCES, aiming at citadel/waterline.

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3 hours ago, Call_of_the_Mastodon said:

Interesting....even after nearly 7k battles I'm still learning things about game mechanics.  I know I've scored HE citadels with Conquerer on Minotaurs and Smolensks, which other cruisers can be citadeled with HE?

Here's a fun graphic I made for the 356mm HE on Duke of York and her ability to penetrate cruisers within her Matchmaking spread (at the time, 88mm of HE penetration, 115mm of IFHE penetration -- these values are different now).  Note that this was current as of December 2017 -- so a long, long time ago.  More ships have been added, some have been re-tiered, some armour values have changed, etc.  The legend is as follows:

TKDJG58.png&key=953158b286b87fdc32ab35fad42991fdb7d1a16e22e5fc31f49ebee3726af27f  - Can be citadelled.  Note, just because it's possible, it doesn't mean it's likelyFor example, the Myoko-class does have an external citadel but only the TINIEST sections of it are poking out.

rS6JgXP.png&key=836f60b356c2e506d836dca8 - IFHE needed to citadel the ship (keep in mind, IFHE provided a 30% increase to penetration back in the day, not 25% like now.)

m4aWKJO.png&key=b5fef2f33e0bd371381374e8959883af370811598dc83a362e49c8b61414064b - No chance in flaming butts of citadelling this ship, either due to a lack of penetration or because the entire citadel was internal.  For example, Cleveland DOES have an external citadel, but you're not going to get through her 127mm belt.

 

dg4J8PH.png
Tier 5.

4R2LxTv.png
Tier 6

hudJegW.png
Tier 7

4UFU5hB.png
Just to give you an idea how out of date these graphics are, at the time of writing (December 2017) there were ten tier 8 cruisers, including clones. There are now twenty-two with the upcoming Soviet cruisers.

IHvigvu.png
Tier 9

 

 

Edited by LittleWhiteMouse

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3 minutes ago, dEsTurbed1 said:

Why can destroyers routinely get HE citadel hits on carriers?

Why does my Drake get HE citadel hits on carriers?

BOTH INSTANCES, aiming at citadel/waterline.

It depends on the carrier.  The answers are always:

  • The citadel is external.
  • The citadel protection is stupid-thin.

Let's look at some examples:

  • Hosho's citadel is external, though it rests just at (or just beneath) the waterline.  It's possible during a high wave that the citadel may be struck.  It has only 20mm of protection, well within the penetration range of most (but not all) destroyer caliber weapons.
  • Langley's citadel is external with 20mm worth of armour.  She's easily citadelled by HE rounds.
  • Hermes' citadel has is external but has 76mm worth of armour.  Only large caliber HE rounds with 1/4 penetration have a chance of citadelling her (select Royal Navy and German battleship rounds).
  • Ryujo's citadel is external and has between 19mm and 25mm (!) worth of protection.  Most destroyer caliber rounds can citadel her (with very very few exceptions).
  • etc...

There is an outside chance to land citadel hits grace of a bug, but this is a very rare occurrence, requiring a specific set of model-breaks to occur (usually while turning at high speed).  This can affect any ship, but you're unlikely to ever experience this. I haven't in the thousands of games I've played, though I have been shown examples.

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4 hours ago, LittleWhiteMouse said:

Spread your hits out to whatever you can damage so you get those meaty unsaturated hits.  Prinz Eugen's 51mm worth of penetration means that she can hit lots of different areas and score those 825-damage chunks across the bow, stern, superstructure, upper hull and deck of most targets she faces.  When you notice the damage lower a bit, adjust fire to a new section.  Eventually you'll saturate most of the areas but your target should be on low health and/or burning nicely at that stage.

My fire RNG is pitiful.  I once had 50 HE hits with my Conq and no fires.  Is there a good or bad place to aim on a ship to start fires?

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Just now, mechengrmike said:

My fire RNG is pitiful.  I once had 50 HE hits with my Conq and no fires.  Is there a good or bad place to aim on a ship to start fires?

Fire is largely RNG based with the following rules:

  • Ships can hold a maximum of 4 fires normally, 3 if they have the Fire Prevention commander skill.
  • You have to hit the location you want to burn.  So if you want a fire to burn on the bow, you have to hit the bow.
  • You cannot start a fire on a section that's already burning.

The fire chance you see in port is the BASE fire chance.  This then gets modified by a formula which includes defensive factors of the target ship which includes tiering, upgrades, commander skills and modifications.  In practical terms, for ships tier 6 and higher, you can estimate that your actual fire chance per shell is about half of what's listed in port (it's more complicated than that, but it gives a pretty close estimation).

So if your cruiser has a 10% fire chance per shell, it's probably going to take you around 20 hits to start a fire (10%/2 * 20).

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4 minutes ago, LittleWhiteMouse said:

Fire is largely RNG based with the following rules:

  • Ships can hold a maximum of 4 fires normally, 3 if they have the Fire Prevention commander skill.
  • You have to hit the location you want to burn.  So if you want a fire to burn on the bow, you have to hit the bow.
  • You cannot start a fire on a section that's already burning.

The fire chance you see in port is the BASE fire chance.  This then gets modified by a formula which includes defensive factors of the target ship which includes tiering, upgrades, commander skills and modifications.  In practical terms, for ships tier 6 and higher, you can estimate that your actual fire chance per shell is about half of what's listed in port (it's more complicated than that, but it gives a pretty close estimation).

So if your cruiser has a 10% fire chance per shell, it's probably going to take you around 20 hits to start a fire (10%/2 * 20).

Thank you. That helps.  I've had people tell me I should be aiming for the wooden deck and not the ships hull.  Sounds like what you're saying is it does not matter where you hit the ship, as long as that portion of the ship is NOT already on fire.

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7 minutes ago, mechengrmike said:

Thank you. That helps.  I've had people tell me I should be aiming for the wooden deck and not the ships hull.  Sounds like what you're saying is it does not matter where you hit the ship, as long as that portion of the ship is NOT already on fire.

You got it.  You can effectively divide the ship into four sections lengthwise, roughly equidistant from one another.  If someone takes the Fire Prevention skill (very common on battleships) sections 2 & 3 in the middle of the ship will merge into one big section.

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5 hours ago, LittleWhiteMouse said:

They don't enter the ship at all -- they explode on the first surface they impact.

Damage Details wall

I hate to argue with you of all people, but I don't think this is correct. (There is a lot of statements from devs and players that say X is how it works, but then I see things in game that completely violate the statement.)

I had a friend run IFHE on Des Moines before the rework and we saw him to a decent amount more damage with it. I asked the forums why that might be, but I sure you can guess how that went. We tried out a theory someone voiced to me, and it it did give us better numbers. The theory was, with IFHE not only would it allow something to pen what it first came into contact with but if it could pen what was behind it, it would doing more damage.

Now, I know that's not how it was supposed to work, but data was consistant. I particularly remember that the IJN Cruisers would take more damage from this, and when I did the math it appears IFHE would allow the rounds to not only pen the SS but also the deck below it. (I have not done a test post rework.)

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1 minute ago, Tyberius_D said:

I hate to argue with you of all people, but I don't think this is correct. (There is a lot of statements from devs and players that say X is how it works, but then I see things in game that completely violate the statement.)

I had a friend run IFHE on Des Moines before the rework and we saw him to a decent amount more damage with it. I asked the forums why that might be, but I sure you can guess how that went. We tried out a theory someone voiced to me, and it it did give us better numbers. The theory was, with IFHE not only would it allow something to pen what it first came into contact with but if it could pen what was behind it, it would doing more damage.

Now, I know that's not how it was supposed to work, but data was consistant. I particularly remember that the IJN Cruisers would take more damage from this, and when I did the math it appears IFHE would allow the rounds to not only pen the SS but also the deck below it. (I have not done a test post rework.)

I have spent literal hours (and hours and hours and hours) testing HE mechanics.  I've also spoken to Sub_Octavian (one of the devs) about HE too.  Barring a model break (which happens sometimes in high speed turns) HE shells always always always explode on the first surface they contact (even then, they're exploding on the first surface they contact, it's just that the model is temporarily busted with missing external surfaces, so the first surface they hit is inside the ship).  It is literally how they are programmed in the code.

You can see spikes in damage for all sorts of reasons -- the most famous of which is after someone hits a Repair Party.  This restores the hit points not only of the ship, but also to any damaged sections of the ship too.  Thus an area that was only yielding saturated damage before (0.1x or 0.165x shell damage) suddenly starts giving back full damage penetrations (0.33x shell damage) until depleted which can be startling. 

All Inertial Fuse for HE Shells does is increase the thickness of armour HE can damage.  It has no impact on the quality of damage.  If you're experiencing something different, link the replay.  That's a bug and it should be reported.

 

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4 hours ago, LittleWhiteMouse said:

Here's a fun graphic I made for the 356mm HE on Duke of York and her ability to penetrate cruisers within her Matchmaking spread (at the time, 88mm of HE penetration, 115mm of IFHE penetration -- these values are different now).  Note that this was current as of December 2017 -- so a long, long time ago.  More ships have been added, some have been re-tiered, some armour values have changed, etc.  The legend is as follows:

TKDJG58.png&key=953158b286b87fdc32ab35fad42991fdb7d1a16e22e5fc31f49ebee3726af27f  - Can be citadelled.  Note, just because it's possible, it doesn't mean it's likelyFor example, the Myoko-class does have an external citadel but only the TINIEST sections of it are poking out.

rS6JgXP.png&key=836f60b356c2e506d836dca8 - IFHE needed to citadel the ship (keep in mind, IFHE provided a 30% increase to penetration back in the day, not 25% like now.)

m4aWKJO.png&key=b5fef2f33e0bd371381374e8959883af370811598dc83a362e49c8b61414064b - No chance in flaming butts of citadelling this ship, either due to a lack of penetration or because the entire citadel was internal.  For example, Cleveland DOES have an external citadel, but you're not going to get through her 127mm belt.

 

dg4J8PH.png
Tier 5.

4R2LxTv.png
Tier 6

hudJegW.png
Tier 7

4UFU5hB.png
Just to give you an idea how out of date these graphics are, at the time of writing (December 2017) there were ten tier 8 cruisers, including clones. There are now twenty-two with the upcoming Soviet cruisers.

IHvigvu.png
Tier 9

 

 

Thanks Mouse! Even if old it's still a useful graphic.  I suppose Thunderer with the 457s might cross the threshold on a few more ships, or no?

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1 minute ago, Call_of_the_Mastodon said:

Thanks Mouse! Even if old it's still a useful graphic.  I suppose Thunderer with the 457s might cross the threshold on a few more ships, or no?

Yeah, Thunderer has 114mm worth of penetration normally and 142mm of penetration with IFHE.  So conceivably you could citadel quite a few cruisers out there with their 5" belts (which are pretty commonplace).  The catch is that these targets are so small, even with Thunderer's accuracy you're not likely to be able to bullseye them so it's not worth the investment.  Especially when it guts your fire chance so heavily.

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20 minutes ago, LittleWhiteMouse said:

Yeah, Thunderer has 114mm worth of penetration normally and 142mm of penetration with IFHE.  So conceivably you could citadel quite a few cruisers out there with their 5" belts (which are pretty commonplace).  The catch is that these targets are so small, even with Thunderer's accuracy you're not likely to be able to bullseye them so it's not worth the investment.  Especially when it guts your fire chance so heavily.

Great info LWM. I know this level of detail exists in the game, I just never wanted to get that technical... (sales background.... lols) thank you for the work, the detail and the help you provide.

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