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"Why can't I citadel Henri's board side?" A detailed analysis of the spaced armor mechanics in World of warships

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     To those that have played world of warships for quite a while, engaging enemies of all shapes and sizes, including the French cruisers, the following might some familiar to you.

"A careless Henri IV has come into view, barely angled. I think she's close enough, I have sufficient penetration. Ohh, I am so going to make him MINE!"

The shells fly true, sticking dead center in the careless cruiser. But, Merdé, there's no citadel, only penetrations, and what's more, it barely does any damage, around 2k~3k!

Tchevo Blyat??!  Does the Henri use black holes for armor?

             To explain what is happening, we need to understand the key mechanics that acts as the armor-piercing shells' principle. 

Let's first examine the armor layout of the French cruiser. (Diagram not drawn to scale)


Alright, moving on to the Armour piercing mechanics. For a shell to penetrate a section of a ship, the mechanics have different priorities.


1. Overmatch. Pretty self-explanatory, and it doesn't matter for this discussion.

2. Bounce check. For normal AP shells, the bouncing angles are between 45-60 degrees. For shells that strikes the armor at an incline more than 60 degrees from the perpendicular line against the armor surface, the shells are guaranteed to bounce. Likewise, for shells that strikes the armor less than 45 degrees, the shells are guaranteed to penetrate, anything in between are under the mercy of RNGesus. (Note: The normalization mechanics only cames into effect after the shell has passed the shell bounce check, and applies only to penetration. In the game, it doesn't really change the trajectory of the shells, and it only works in penetration calculations)(Note 2: As we should all know, some ships have modified angles, like 60-67 degrees for tier 8,9,10 USN heavy cruisers and the Hood, 60-75 for British cruisers, etc. etc.)

3. Penetration check. This is pretty straightforward. Your shell loses penetration over distance due to multiple factors, and if you have enough penetration to overcome the thickness of the armor, after normalization and shell bounce check, the shell goes through. If not, well, idi nahui!

4. Shell fuse prime check. For a shell to began arming the fuse, it needs to penetrate at least 1/6th millimeters of  Equivalent Armor for the shell fuse to prime. The word "Equivalent Armor" is important. For example, Yamato's AP shell requires 77mm of armor to prime, and a Khabarovsk's belt is 50mm. Theoretically, every shell that struck the ship should over-penetrate, but if you angle, therefore increasing the relative equivalent armor past 77mm, the shell will prime, and your boat is pizdec. The equivalent armor is calculated by     Armour Equivalent = COS( Vertical shell drop angle + Armour angling - normalization)

5. Shell fuse time and shell travel time. After penetrating an armor belt and with the fuse primed, the shell began its deadly timer and continues on its merry way into the enemy ship. After penetrating an armor, the shell does not lose speed, only penetration. For example, if a shell has 300mm of penetration at the point of impact, and it struck a 50mm armor belt, the shell will have 250mm of penetration as it continues inside the ship. The Overmatch, Bounce, and Penetration check will activate EVERY TIME the shell meets a piece of armor. There are two ways that your shell can overpenetrate. Either the caliber of the shell is too great, and the shell never met enough armor to prime the shell through the entire ship, or the shell is too fast, and the enemy ship is too narrow, that by the time the shell fuse run out, the shell has already left the enemy ship. Again, some special cases have special treatments, all British cruisers have a shell prime threshold of only 12mms.  (Note: On the rumors of "Citadel overpenetration" it isn't true. If your shell failed to prime even after penetrating the entire citadel of the enemy ship, the shell will over penetrate through the citadel and do nothing special) 

      Okay, back on topic. Why does the Henri IV eat your armor-piercing shells and receive little damage?

The answer lies in the empty space between the main belt and the citadel bulkhead. The 140mm main belt is enough to prime any shell in the game, which means for the shell to fail to citadel the Henri IV, the shell is either too slow, have too short of a fuse, or doesn't have enough penetration to penetrate the citadel bulkhead. The empty space between the main belt and the citadel bulkhead have extremely low modular health, meaning it can saturate very easily, and should a shell detonate in this section, the ship takes minimal damage.

To test this, we must first know the shell fuses that are present in World of Warships

1. Small caliber destroyer guns with a caliber of 130mm and below have a fuse delay of 0.01 seconds.

2. 130mm-155mm light cruiser guns have a fuse delay of 0.025 seconds.

3. 180mm-460mm heavy cruiser and battleship guns have a fuse delay of 0.033 seconds.

(Again, special cases. British battleships (excluding Warspite and Vanguard) have a fuse time of 0.015 seconds, while British cruisers (excluding payfast) not only have a fuse time of 0.005 seconds but also have an extremely sensitive fuse that primes the shell after penetrating only 12mms of armor.)   

      Let's prove it.


Take, HMS Neptune, for example.


Which means


This can and will happen. Penetration isn't an issue, at this range, Neptune can citadel Des memes and Moskau just fine. Which means it's time to run the shell through our mechanics. 

Neptune's shells exit the barrel at a velocity of 768 m/s, barely loses and penetration or velocity at such close range, after penetrating the 19mm torpedo bulge, the extremely autistic and hypersensitive British shell primes, and continues to travel toward the citadel for 0.005 seconds. The shell can travel around 3.75 meters during this period, which is not enough for the shell to reach the citadel.


So, let's crank up the steam, and see if we find the sweet spot between citadels and disappointment.


Let's take out my personal favorite, the Graf Spee, striking the Henri IV at a range of 10.6km


The Graf Spee have a short-fused shell. The shell will detonate after 0.01 seconds after priming the fuse. The shell can travel slightly less than 5.11meters after penetrating the main armor belt of the Henri IV. Is it enough? Well, the answer is quite mixed. Sometimes citadels are scored, sometimes the shells caused zero to no damage. This is because of the 20 degrees incline of Henri's main belt, the higher the shell lands above the waterline, the bigger the distance the shell have to cover in the empty space.


      So, what does this all mean?

This means that any shell that ran out of fuse time and detonates in the Henri's spaced armor will be absorbed with minimal damage caused. And not just because the shell ran out of fuse time. We can expand on this mechanics. 

Remember the shell bounce mechanics? It applies every time a shell strikes a piece of armor.

So, let's suggest if a Montana's 406mm superheavy shell stuck a Henri 10km away, at 60 degrees, and the Montana is lucky enough to pass the shell bounce check and go through the main belt. The shell has a velocity of 564m/s at this range, with a 0.33 second fuse time, the shell can travel around 18.6 meters before detonating, way further than the 10 meters effective empty space. Then why can the shell still be absorbed?

The answer lies in the citadel bulkhead. Again, the shell bounce mechanics applies every time a shell meets a hard place. Despite passing the shell bounce check at the main belt, the 45mm citadel bulkhead is too thick to be overmatched, and the shell bounce mechanics is applied again. If the RNG dictates that the shell bounced, the shell will detonate inside the empty space between the main belt and the citadel, and cause minimal damage.


Another infamous example is the British BB HE shells. We can consider the HE shell as an AP shell that doesn't bounce, have perfect normalization, have a fuse that primes after meeting any armor, with an absolute 0 fuse time. Let's take Conqueror with 419mm guns (because 457mm guns don't matter and we all know it) against the Emile Bertin, the shell will easily penetrate the belt of the unarmoured cruiser and detonate immediately. Despite having enormous penetration, the shell will never touch the citadel and cause minimal damage. Try this for yourself, take a British BB to the training rooms, aim at an Emile Bertin at point-blank range dead at the waterline, it watch it cause at most 3000 damage.


French cruisers are broken plz nerf The unique armor layout gives the French cruisers unique advantages, that especially rewards angling while tolerating more mistakes against certain ships. If you find yourself in a British cruiser or a destroyer, shooting at a Henri, it might not be the best idea to aim for the main belt. Try to aim for the higher auxiliary hull, where you can score reliable 1/3 or 1/6 damage depending on the point of impact.

Edited by The_first_harbinger
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In addition, shell's velocity after impact is likely determined by this equation: 

v_2 = v_1 * (1-exp((d-p)/d))

p: penetration d: layer thickness v: velocity before and after


I do also have a program that can calculate post pen detonation distance after penetrating single plates of armor though it does not yet work with multiple plates - so if anyone wants some data from that I am happy to provide it. 

Edited by 901234

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Because the Henri is [edited]broken as crap. Setting aside the fact that it has way too long a range, a speed boost that makes it impossible to hit, and oversized guns that should really classify it as a battle cruiser, plus the stupid [edited]heal that no cruiser should have, it also gets spaced armor which basically turns it into a German battleship. It's the most overpowered cruiser in the game bar none and seriously needs to be nerfed. 

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Nice write-up on this matter! I certainly learned something new. The spaced armour scheme should be looked at for Henri, at least. While the ship is not overpowered (rather being the best-fitting cruiser in the meta where concealment hardly matters), it's one of the more difficult cruisers to kill. While she is easy to citadel whilst angled, you often don't deal devastating volleys to it, even when any other cruiser would have been punished. It's far too-common to not deal much damage to the ship. A proper nerf, would be to remove the spaced amour and have it rely on it's 25mm plating and 30mm hull plating. If that is too harsh of a nerf, then the bow and stern plating could be buffed to 27mm. Personally, I think she should be more of a glass cannon, since her speed is her primary defense against shells, and her firepower is fantastic. I can see players dying more often, if they don't have that spaced armour to save them.

And I don't mean to brag, as I am merely using this information to make a valid point - even as among the top Henri players on the NA server, she deserves to have her spaced armour removed. That is the main problem of the ship. The speed and firepower make up for the 25mm plating and the massive detection range (15.9 Km if you run the Legendary Mod). Nerfing her firepower would result in Henri having to stay back even further than it already does - not that its concealment keeps it from getting that much closer, or anything. And when Henri sits back, especially with a competent player behind the wheel, the more of a pain it becomes to land shots on the thing. Giving more incentive for this ship to hang even further back, is not healthy for the game, and it will make the ship worse at contributing to a match. As I've already stated, her speed is enough of defense for her, to stay in the match long-enough. Removing the spaced armour, would just mean that if you hit the ship, you will be better-rewarded for proper aim, than you currently are. It is not fun, nor is it rewarding, to land your [BB]shells on the ship, only to inflict minimal damage.

I love playing my Henri, but I must say that the spaced armour scheme is ridiculous. Feel free to disagree with my opinion. If you have a better idea on how to nerf or rework the ship, please let me know.   I like hearing the opinions of others, honestly.



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*Makes an incredibly informative forum post that is very thoroughly researched and helpful to many people*

*Spells broadside wrong*

Edited by Iron_Salvo921

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One of the largest problems with the actual mechanics of WoWS as a game is the shell vs armor code. Not as code itself, but as to what it's purpose is.

In a word, it's far too complicated.

So why is this a problem?   Because it leads directly to the bugbear of all video games:  massive inconsistency.

WG seems to be of two minds here:  on one hand, they seem to be almost fetishist in desire to "correctly" model ship design, and slavishly follow real-world physics when it comes to shell flight.   On the other hand, they're trying to run a video game, and not a simulator, as evidenced by lots of other game mechanics (e.g. autobounce, overmatch, smoke screen behavior, etc).  Note I'm talking only about game mechanics, not about specific game features (e.g. "consumables", et al.)

Unfortunately, these two mindsets are in direct conflict:  one cannot have a simulator AND a video game, because the goals of each are diametrically opposed.

Simulators are for one thing, and one thing only:  mimicking real life as closely as possible, usually so that the user can experience directly that a real life situation is like.  Training is the primary function of simulators, with entertainment a far, far, far distant 100th on the priority list.

Video Games, on the other hand, are for entertainment, pure and simple. Any resemblance to Real Life exists only to further the goal of entertaining the user.


So here's the issue:  WoWS is a video game. It's marketed as a video game. It's player base expects a video game, because that's (a) what they were sold/promised, and (b) what they want, as evidenced by the complete lack of success of any "ship simulator" from anywhere, unlike, say Flight Simulators.

And in video games, one of the very first things you learn about designing them is that player enjoyment is directly tied to repeatability.  This is a psychological phenomena, going back to the old Pavlov's Dog experiment (actually well before that):  do X, get Y.   It's not "do X, maybe get Z, or Y, or Q, or P, or maybe you get nothing."

There's some room for flexibility, in that users can alter their expectations a bit so that they don't 100% have to get Y after "doing X", particularly if they can perceive that "doing X" is a bit fuzzy. For example, in console games, if you hit the button sequence A-B-B-A, users will not be upset if the timing between hitting sequential keys alters the outcome a bit.  That is, they understand that the length of pause is part of the sequence, as much as which keys are hit.   But what users will NOT tolerate is if the length of "acceptable" pauses to get the same outcome is too narrow.  That is, if the user *reasonably* thinks they're doing the exact same thing they did last time to get Y, and it doesn't yield Y again, they get upset. 

So where is this going?

Well, tell me, how much of the time in WoWS to YOU, the player, reasonably think you've done the exact same thing you've done hundreds of times before, but get wildly different results?

Yeah, ALL the time.

In the field of User Interface Design (which is a fusion of the SCIENCES of psychology and engineering), this is called a Negative User Experience.

The Armor vs Shell mechanics are heavily to blame for this negative enjoyment. Simply because they are so complicated, and introduce so many small variations, as well as explicit Randomness, into the simple "do X, get Y" calculation.  That's why everyone gets pissed off - you simply can't see or even compensate for these variations, to reliably get even a rather modest range of outcomes, consistently. 

The console equivalent would be the aforementioned A-B-B-A sequence, requiring 5ms or less between button presses to get the expected outcome. BUT, having the game itself introduce a random 1ms to 10ms delay itself. 

In both cases, the level of randomness and imperceivable variation is so high that it negates virtually any skill from the user.


No matter how much we strive to understand the mechanics, it won't fix the underlying problem:  that the inherent design flaw which introduces far too much variability in results is one of the PRIMARY reasons for dissatisfaction in playing WoWS.

It's never going to be fixed, because WG has made an intrinsic mistake when designing the game itself:  they forgot their #1 job was entertaining the user, not providing a reality simulator.  It's really a pretty bad one, given that the research of User Experience principles has been known for almost 5 decades at this point.

So the OP's explanation, while interesting from a technical standpoint, simply is irrelevant to virtually everyone:  you merely now know WHY you're frustrated, not that there is anything you can do to STOP being frustrated.




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