Interpreting in-game specifications - A quick guide

Intro

This thread aims at helping you grow you own sense of analyzing and comparing data and specs of different ships in World of Warships. I’ll start with introducing the meaning of different specs and how they affect gameplay.
Having an objective mind is first step of becoming julao, and it is fundamental to addressing any reason to other people. You need to understand why a ship (or a type of ship) is effective or ineffective for certain tasks during gameplay. A good understanding of existing ships might also help you master new ships faster and smoother.

In-game mechanisms are based on but not entirely complying to actual physics. I’ll address each title without presenting too much boring slides you’d see in a physics or maths lecture. But you are always welcome to find your own references.
A WOWS starter may find the information confusing and difficult. I recommend you to start from the very beginning and read along the paragraphs as you step further into a more involving gaming experience.

Ballistics

Muzzle velocity
The shells bore speed, Foxhole ballistic speed is affected by air resistance attenuation over distance, which indirectly determines the penetration depth

Projectile mass
I don’t really have to explain weight, right? ——Heavier shells often have better terminal velocity cause less interference by air resistance.
I'm gonna stay away from yobbling physical formulas. But you'd know heavier objects preserve momentum better than lighter objects.

Air resistance/Air drag
Specifically, the air resistance coefficient (as per aerodynamic laws). This parameter determines the tendency of velocity loss a shell might endure during travelling. Greater air resistance coefficient means more velocity loss the shell endures. It also affects penetration.

Summary
Muzzle velocity, shell weight and air resistance coefficient together dictate the ballistics and penetrating potential of a given type of armor-piercing shells. At a fixed distance:
Greater shell weight (heavier shells) means better penetration.
Higher muzzle velocity means better penetration.
Greater air resistance means more severe velocity loss at the end of shell trajectory, curvier arcs and steeper penetration angle.
These three parameters affect the performance of AP shells as stated above.
The actual penetration (thickness) varies at different distances, which is the reason WG provides not a single entry for a fixed value of penetrating power.
The actual formula of calculation is not published but in-game experience somewhat complies to real world AP shell performance of getting through vertical and horizontal armor plates.
*Vertical penetration: penetration of vertical armor plates, usually belt armor and internal side armor.
*Horizontal penetration: penetration of horizontally aligned armor plates (e.g. armored decks & internal roofs).
Flatter arcs often have better penetration against vertical armor, whereas curvier arcs often perform better at getting through horizontal armor Commonly known as the Trebuchet.

Penetration

Angle adjustment/Normalization angle
A coefficient to compensate the turning of a shell when entering armored components. it affects calculations of effective distance of a shell travelled ‘inside’ armor plate(s) and dictates the entry angle of an armor piercing shell upon hitting the target.
For example, an AP shell is supposedly hitting a vertical armor plate with an angle of 45 degrees, an adjusting factor of 5 degrees kicks in and resulting in a final penetrating angle of 40 degrees, which was then put into further calculation of shell travel distance, then the final penetration value.

Ricochet
Ricochet is possible when contact angle is greater than 45 degrees.
If contact happens with an angle greater than 60 degrees, penetration will happen ONLY when caliber of the AP shell is greater than 14.3*(calculated penetration value), this is called overmatching mechanism of AP shells.
*FYI, 8-inch AP shells fired by US heavy cruisers have an overmatching threshold of 67.5 degrees, resulting in a feel of much better penetration comparing to other heavy cruisers.
*AP shells of certain ships may have been given specific overmatching specs.

Indication of a penetration or ricochet follows such a fashion: If a shell hits the target,
Firstly, overmatching mechanism kicks in and determines whether it is a ricochet. If not (angle steeper than threshold or caliber overmatch), RNG then take effect when contact angle falls in the ‘possible ricochet’ zone (usually 45-60 degrees). If not a ricochet,
Adjust entry angle of the shell by taking away a fixed adjustment value (angle adjustment coefficient) from the initial contact angle value, then calculate armor travel distance using the adjusted angle value accordingly.

Damage

Rated damage of armor piercing/high explosive shells
The maximal damage a shell inflicts upon hitting the target, happens when a shell arms inside the citadel.
Shells armed inside a ship but not in the citadel areas would deal 33% of maximal damage.
If a shell penetrates the ship but failed to arm (will explain later) inside the ship, you’ll get 10% of maximal damage.
Salvo while under a plural hit damage does not follow the above rules, but use the formula to calculate the final damage alone, the formula is not currently known.
Therefore, there isn’t an established semi-citadel or para-vital area in the armor layout.

Fuse arming distance/Detonator threshold
This is a resemblance of squeezing and deforming of actual AP shells hitting the target, which translates to minimal penetration distance required to arm the fuse in-game.
For example, 220mm AP shells Moskva (tier X Russian cruiser) fires require a minimal arming distance of 57mm, if calculated armor-penetrating distance falls below this value, the fuse would not arm, resulting in minimal damage dealt by this shell.

Fuse delay/Projectile detonator
Fuze to explode after the onset of the time required for most AP of large caliber projectile fuze delay 0.033 seconds, HE fuses the delay to 0.001 secondsShane's 283AP and Pugs 130AP 0.01 seconds.
A shell continues travelling during fuse delay. This could also affect the precise location a shell detonates, and subsequently the damage dealt.

Summary
Rated damage is not the only spec indicating the power of a certain shell. Fuse arming distance and fuse delay also have substantial influences on the damage inflicted by the shell during an effective penetration.A citadel penetration with a wrong distance & wrong angle will also dealt a overpen damage.
That is why even a powerful main armament carried by Moskva——could result in dissatisfied damage output.

HE

Penetration value of HE shells
Each HE shell is given a fixed penetration value of 1/6 of its caliber, with German Battleships enjoying better HE penetration of 1/4 of their calibers.
HE penetration potential is NOT affected by ballistics. For example, a shell with 100mm penetration potential would penetrate any armor less than 100mm thick.
*Whether this shell arms inside the citadel, however, depends on the armor layout of target hit by the shell.

Blast radius/Explosion size
This parameter is currently not clearly interpreted. All we know is that the greater the radius the better HE shells perform. It is correlated with caliber of course.

Projectile krupp
This parameter may be used to simulate bullet hat, specific mechanisms are not known, role in the current version of lower compared to other parameters

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