Shell Characteristics

In World of Warships: Legends, guns in general include multiple complex mechanics which require more in-depth knowledge of the game to understand correctly. For the basics, please check the Gunnery and Shell Types pages.

Accuracy

Illustration of artillery dispersion

However perfectly a naval gun on a stationary ship may be laying, successive rounds will not impact on a single point but will fall in a pattern scattered both in deflection and in range. This phenomenon is called dispersion and, irrespective of human and constant error, it is caused by multiple inherent factors: minor variations in the weight of the projectile, differences in the rate of ignition of the propellant, variations in the temperature of the bore from round to round, physical limitations of precision in setting values of deflection and quadrant elevation on the respective scales, minor variations in wind, air density or air pressure, and so on.

Shell dispersion

Observing the position of the surface bursts around our point of aim, we find that they fall into a roughly elliptical area in relation to the line of fire. An ellipse constructed around the dispersion area is called the dispersion ellipse. Every time a player orders his main caliber guns to fire, the game engine constructs a 2-D ellipse around the point of aim, and does so independently for each salvo fired. A double-tap on the gun trigger will fire all guns in one salvo with one dispersion ellipse, sequential fire will construct dispersion ellipse for each turret salvo separately. This ellipse has a certain length and width values, which are dependent on the characteristics of the gun.

Shell impacts within the dispersion ellipse are not uniformly distributed over the surface, but lie more thickly towards the center of aim. The intensity with which the shells fall in different points of the area of dispersion, can be described by a Gaussian (normal) distribution. If the shooting distance is below the maximum range, the horizontal dispersion value decreases accordingly. Horizontal dispersion values at distances other than maximum firing range, as well as the vertical dispersion values have not been made public by Wargaming. However, based on the user collected data we know lines of tech tree ships are tied to specific formulas to determine horizontal dispersion.

Sigma

Sigma is one of the parameters for gunnery in World of Warships: Legends. It describes the tendency of a shell to land closer towards the center of aim, a.k.a. the middle of the dispersion ellipse described by 'vertical dispersion' and 'horizontal dispersion'. The higher the Sigma value, the more likely the shells are to land closer to the center.

The graphic below showcases a high sigma (blue) and an average sigma (red) and their respective distribution of shells on the horizontal axis. The dotted line is the normal distribution generated from these results. Note that those values have been gathered by PC's World of Warships players in training rooms and are thus not 100% accurate, however, they do demonstrate roughly how sigma works.

Sigma parameters are mostly uniform for destroyers and cruisers but vary drastically for the battleships. For example, most cruisers and destroyers have a base Sigma value of 2.0, which is relatively standard. However, when comparing ships such as the Tier VII Italian tech-tree battleship Vittorio Veneto, which has a Sigma of 1.7 and Tier VII Italian premium battleship Roma, which has a 1.8 Sigma, it can be seen that Roma is technically more accurate than Veneto.

——  All Ship Sigma Values  ——  

Class	Ship	Tier	Nation	Sigma Value
	Stalingrad	★		2.4
	Napoli (B)	★		2.15
	Khabarovsk	★		2.1
	Ibuki B	VIII		2.1
	Krasny Krym	IV		2.1
	Pyotr Bagration	VII		2.1
	Gorizia	VI		2.1
	Indianapolis (B)	VI		2.05
	Congress	VII		2.05
	San Diego	VII		2.05
	Plymouth	VII		2.05
	Perfect 10	VII		2.05
	Buffalo	VIII		2.05
	Seattle	VIII		2.05
	Tulsa	VIII		2.05
	Salem	VIII		2.05
	Ibuki	VIII		2.05
	Takahashi	VIII		2.05
	Roon	VIII		2.05
	Schröder	VIII		2.05
	Ägir	VIII		2.05
	Carnot	VIII		2.05
	Dmitri Donskoi	VIII		2.05
	Kronshtadt	VIII		2.05
	Brindisi	VIII		2.05
	Alaska	★		2.05
	Worcester	★		2.05
	Des Moines	★		2.05
	Yoshino	★		2.05
	Zaō	★		2.05
	Minotaur	★		2.05
	Brisbane	★		2.05
	All destroyers (except Khabarovsk)	II - ★	All	2.0
	All cruisers (except Mikasa ('23) and Charleston (M))	I - II	All	2.0
	All cruisers (except Krasny Krym)	III - V	All	2.0
	Ishizuchi	III		2.0
	Kawachi	III		2.0
	Repulse	V		2.0
	(AL) Queen Elizabeth	V		2.0
	Warspite (B)	V		2.0
	Prinz Eitel Friedrich	V		2.0
	Daisen	VIII		2.0
	Boise	VI		2.0
	Helena	VI		2.0
	New Orleans	VI		2.0
	Nagato	VI		2.0
	Omono	VI		2.0
	Eastern Dragon	VI		2.0
	Southern Dragon	VI		2.0
	Maya	VI		2.0
	Myōkō	VI		2.0
	Belfast	VI		2.0
	Belfast '43	VII		2.0
	(AL) Cheshire	VI		2.0
	Fiji	VI		2.0
	Surrey	VI		2.0
	Tiger '59	VI		2.0
	Duke of York	VI		2.0
	Collingwood	VI		2.0
	Resistance	VI		2.0
	Yorck	VI		2.0
	Cross of Dorn	VI		2.0
	München	VI		2.0
	Scharnhorst (B)	VI		2.0
	Algérie (W)	VI		2.0
	Charlemagne	VI		2.0
	Shchors	VI		2.0
	Tallinn	VI		2.0
	(AL) Zara	VI		2.0
	Abruzzi	VI		2.0
	Chumphon	VI		2.0
	Cleveland	VII		2.0
	Wichita CE	VII		2.0
	AL Montpelier	VII		2.0
	Anchorage	VII		2.0
	Rochester	VII		2.0
	Shimanto	VII		2.0
	Mogami	VII		2.0
	Azuma	VII		2.0
	Atago (B)	VII		2.0
	Albemarle	VII		2.0
	Edinburgh	VII		2.0
	Celtic	VII		2.0
	Vanguard	VII		2.0
	Hipper	VII		2.0
	Weimar	VII		2.0
	Mainz (CE)	VII		2.0
	Prinz Eugen	VII		2.0
	Siegfried	VII		2.0
	Odin	VII		2.0
	Charles Martel	VII		2.0
	Champagne	VII		2.0
	(AL) Chapayev	VII		2.0
	Kutuzov (W)	VII		2.0
	Ochakov	VII		2.0
	Amalfi	VII		2.0
	Harbin	VII		2.0
	Izumo	VIII		2.0
	Neptune	VIII		2.0
	Drake	VIII		2.0
	République	VIII		2.0
	Sejong	VIII		2.0
	Ohio	★		2.0
	Colbert	★		2.0
	Henri IV	★		2.0
	Viribus Unitis	IV		1.95
	Bismarck (B)	VII		1.95
	Vermont	★		1.95
	Myōgi	IV		1.9
	Nikolai I	IV		1.9
	Giulio Cesare	IV		1.9
	Rasputin	V		1.9
	Colorado	VI		1.9
	Ignis Purgatio	VI		1.9
	Ragnarok	VI		1.9
	Nelson (W)	VI		1.9
	Toulon	VI		1.9
	Poltava	VI		1.9
	Baltimore	VII		1.9
	Alabama	VII		1.9
	Kansas	VII		1.9
	AL New Jersey	VII		1.9
	Constellation	VII		1.9
	Tirpitz (B)	VII		1.9
	Gascogne	VII		1.9
	Minnesota	VIII		1.9
	Iwami	VIII		1.9
	Marco Polo	VIII		1.9
	Suzuya	VII		1.85
	Riga	VII		1.85
	Maine	VIII		1.85
	Hizen	VIII		1.85
	Petropavlovsk	VIII		1.85
	Montana	★		1.85
	Großer Kurfürst	★		1.85
	Charleston (M)	II		1.8
	South Carolina	III		1.8
	Bellerophon	III		1.8
	Kaiser	III		1.8
	Nassau	III		1.8
	König Albert	III		1.8
	Courbet	III		1.8
	Turenne	III		1.8
	Nevada	IV		1.8
	New York	IV		1.8
	Oklahoma	IV		1.8
	Texas (Alpha)	IV		1.8
	Kongō	IV		1.8
	ARP Kirishima	IV		1.8
	ARP Haruna	IV		1.8
	Iron Duke	IV		1.8
	König	IV		1.8
	Bretagne	IV		1.8
	Okt. Revolutsiya	IV		1.8
	Arizona	V		1.8
	California	V		1.8
	Tennessee	V		1.8
	West Virginia	V		1.8
	Hyūga (W)	V		1.8
	Renown	V		1.8
	Bayern	V		1.8
	Dunkerque (B)	V		1.8
	Ashitaka	VI		1.8
	Hood	VI		1.8
	King George V	VI		1.8
	Gneisenau	VI		1.8
	Strasbourg	VI		1.8
	AL Baltimore	VII		1.8
	Wichita	VII		1.8
	Georgia (W)	VII		1.8
	Iowa	VII		1.8
	Missouri	VII		1.8
	Massachusetts (B)	VII		1.8
	Amagi	VII		1.8
	Monarch	VII		1.8
	Lion	VII		1.8
	Brandenburg	VII		1.8
	Cherbourg	VII		1.8
	Jean Bart	VII		1.8
	Richelieu	VII		1.8
	Flandre	VII		1.8
	Roma	VII		1.8
	Atlântico	VII		1.8
	Temeraire	VIII		1.8
	Friedrich der Große	VIII		1.8
	Brest	VIII		1.8
	Yamato	★		1.8
	Conqueror	★		1.8
	Bourgogne	★		1.8
	Karl XIV Johan	VIII		1.8
	Pyotr Velikiy	IV		1.7
	Mutsu (B)	V		1.7
	Atlanta (B)	VI		1.7
	Flint	VI		1.7
	Florida	VI		1.7
	North Carolina	VI		1.7
	Leviathan	VI		1.7
	Francesco Caracciolo	VI		1.7
	Kii	VII		1.7
	Zieten	VII		1.7
	La Foudre	VII		1.7
	Lenin	VII		1.7
	Vittorio Veneto	VII		1.7
	Prinz Rupprecht	VIII		1.7
	(AL) Sovetsky Soyuz	VIII		1.7
	Giuseppe Verdi	VIII		1.7
	Schlieffen	★		1.7
	(ARP) Musashi	VIII		1.65
	Tiger	IV		1.6
	Derfflinger	IV		1.6
	Cavour	IV		1.6
	New Mexico	V		1.6
	Primal	V		1.6
	Mackensen	V		1.6
	Normandie	V		1.6
	Izmail	V		1.6
	Andrea Doria	V		1.6
	Rooke	VI		1.6
	Hawke	VII		1.6
	Anhalt	VII		1.6
	Vladivostok	VII		1.6
	Alsace	VIII		1.6
	Lepanto	VIII		1.6
	Cristoforo Colombo	★		1.6
	Von Der Tann	III		1.55
	Wyoming	III		1.5
	Arkansas (FE)	III		1.5
	Orion	III		1.5
	Agincourt	III		1.5
	Knyaz Suvorov	III		1.5
	(AL) Fusō	V		1.5
	Heat Ray	V		1.5
	Prinz Heinrich	VI		1.5
	Lyon	VI		1.5
	Sinop	VI		1.5
	Pommern	VIII		1.5
	Gangut	III		1.4
	Dante Alighieri (B)	III		1.4
	Marlborough	VIII		1.4

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Overmatch

An AP or SAP shell whose diameter is greater than 14.3 times the thickness of an armor plate will overmatch and pass through it regardless of angle. Here are some thresholds where this occurs, which determines whether it is feasible to "bow-tank" a particular AP shell.

Armor Thickness	Minimum Caliber to Overmatch	Notes
10 mm	144 mm	Will bounce most destroyer shells (except German 150mm guns) if sufficiently angled, but not most light cruiser shells.
13 mm	186 mm	Will bounce light cruiser shells if sufficiently angled but not heavy cruiser shells (203 mm and larger).
16 mm	229 mm	Will bounce almost all cruiser shells if sufficiently angled.
19 mm	272 mm	Will bounce up to 10-inch (254 mm) shells if sufficiently angled.
25 mm	358 mm	Will bounce up to 14-inch (356 mm) shells if sufficiently angled.
26 mm	372 mm	Will bounce up to 14-inch (356 mm) shells if sufficiently angled.
27 mm	387 mm	Will bounce up to 15-inch (381 mm) shells if sufficiently angled.
30 mm	430 mm	At the moment, République (431 mm), Georgia (W) (457 mm), Ohio (457 mm), Vermont (457 mm), (ARP) Musashi (460 mm) and Yamato (460 mm) can overmatch.
32 mm	458 mm	At the moment, (ARP) Musashi and Yamato (both 460 mm) can overmatch.

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Ricochet Angles

As mentioned in the related article, Armor-Piercing shells may often bounce off the armor of certain ships depending on their caliber and the armor thickness they face (see Overmatch above).

Legends' AP Shell Characteristics

Ship Types	Ships	Chances of Ricochet	Guaranteed Ricochet
IJN Destroyer	Tachibana	91°	–
British Light Cruisers	Weymouth, Caledon, Danae, Emerald	65°	80°
British Light Cruisers	Leander, Fiji, Edinburgh, Plymouth, Minotaur	60°	75°
US Heavy Cruiser	Wichita CE	60°	75°
Premium British Battleships	Hood, Duke of York	60°	67.5°
Pan-Asian Destroyer	Northern Dragon	60°	67.5°
Destroyers	ZF-6, Z-31, Elbing, G. J. Maerker, F. Schultz, Jutland, Daring	60°	67.5°
American Heavy Cruisers	Pensacola (B hull), New Orleans, Indianapolis, (AL) Baltimore, Anchorage, Rochester, Celtic, Wichita, Alaska, Des Moines	60°	67.5°
Italian Battleships	Andrea Doria, F. Caracciolo, V. Veneto, Lepanto, C. Colombo	55°	70°
Russian Cruisers	Stalingrad, Tallinn, Riga, Pyotr Bagration	55°	65°
Russian Cruiser	Petropavlovsk	50°	65°
Japanese Battleships	(ARP) Musashi, Yamato	50°	65°
German Battleships	Bismarck	45°	65°
British Heavy Cruiser	(AL) Cheshire	45°	65°
–	All other ships	45°	60°

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HE Penetration

High Explosive shells have more complex mechanics than the basic "setting fires". Every HE shell has a fixed penetration value that allows it to penetrate a certain amount of armor.

Legends' HE Penetration Rules

Rule
Special Rule	German battleships' 105 mm secondary batteries: 20 mm AL Chapayev's main batteries: 37 mm Jutland and Daring's main batteries: 20 mm Kitakaze's main batteries: 30 mm
1/4 (Caliber÷4)	British battleships' main batteries (except for Warspite (B), Hood and the Tiger to Duncan line) German battleships' main batteries ≥149 mm German cruisers' main batteries ≥127 mm German battleships' secondary batteries (128 mm = 32 mm of pen | 150 mm = 38 mm of pen) Schröder's secondary batteries Atlântico's 234 mm secondary batteries Friedrich der Große's 105 mm secondary batteries Main batteries of (AL) Cheshire, Drake, Makarov, (ARP) Musashi, Yamato, ZF-6, Z-35, Z-46, Z-31, G. J. Maerker, F. Schultz, Z-52 and Bulletproof
1/5 (Caliber÷5)	Main batteries of Akizuki, Bayard, Ochakov, Worcester, Belfast '43, Shimanto, Seattle, Takahashi and Brisbane
1/6 (Caliber÷6)	All the other ships

Examples

The Tier VII American tech-tree cruiser Cleveland is armed with 152 mm main battery guns. The 1/6 rule yields a value of 25 mm of HE shell penetration.

The Tier VI British premium battleship Nelson is armed with 406 mm main battery guns. The 1/4 rule yields a value of 101 mm of HE shell penetration.

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