Shell Characteristics
Contents
Accuracy
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.
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 (B), Elephant | VII | 2.1 | ||
Gorizia | VI | 2.1 | ||
Brindisi | VIII | 2.1 | ||
Resistance | 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 | ||
Vallejo | 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 | ||
Alaska (B) | ★ | 2.05 | ||
Worcester | ★ | 2.05 | ||
Des Moines | ★ | 2.05 | ||
Yoshino | ★ | 2.05 | ||
Zaō | ★ | 2.05 | ||
Minotaur | ★ | 2.05 | ||
Brisbane | ★ | 2.05 | ||
Venezia | ★ | 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 | ||
I.K.S. BortaS | 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 | ||
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 | ||
Nebraska | 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 | ||
Hampshire | 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 | ||
Schill | VII | 2.0 | ||
Odin | VII | 2.0 | ||
Scharnhorst '43 | 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 | ||
Michelangelo | VIII | 2.0 | ||
De Zeven Provinciën | VII | 2.0 | ||
Harbin | VII | 2.0 | ||
La Perla Azul | VII | 2.0 | ||
Borodino | 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 | ||
Tirpitz (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 | ||
Connecticut | 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 | ||
Montana | ★ | 1.9 | ||
Louisiana | ★ | 1.9 | ||
Gascogne | VII | 1.9 | ||
Minnesota | VIII | 1.9 | ||
Delaware | VIII | 1.9 | ||
BA Tirpitz | VII | 1.9 | ||
Iwami (B) | VIII | 1.9 | ||
Marco Polo, Centurion | VIII | 1.9 | ||
Suzuya, | VII | 1.85 | ||
Riga | VII | 1.85 | ||
Maine | VIII | 1.85 | ||
Hizen | VIII | 1.85 | ||
Petropavlovsk | VIII | 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 (1944) | 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 | ||
D'kyr | 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 | ||
Saint Louis | VIII | 2.0 | ||
Ba Montana | ★ | 1.8 | ||
Yamato | ★ | 1.8 | ||
Conqueror | ★ | 1.8 | ||
Bourgogne | ★ | 1.8 | ||
Karl XIV Johan | VIII | 1.8 | ||
Florida | VI | 1.75 | ||
Pyotr Velikiy | IV | 1.7 | ||
Mutsu (B) | V | 1.7 | ||
Atlanta (B) | VI | 1.7 | ||
Flint | 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 | ||
Rio de Janeiro | IV | 1.7 | ||
(ARP) Musashi | VIII | 1.65 | ||
Tiger | IV | 1.6 | ||
Queen Mary | 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 | ||
Duncan | VIII | 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 | ||
Navarin | VIII | 1.5 | ||
Lyon | VI | 1.5 | ||
Sinop | VI | 1.5 | ||
Pommern (B) | VIII | 1.5 | ||
Gangut | III | 1.4 | ||
Dante Alighieri (B) | III | 1.4 | ||
Marlborough | VIII | 1.4 |
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. |
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).
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° |
British Heavy Cruiser | Hampshire | 60° | 75° |
Russian Cruiser | Elephant | 60° | 75° |
US Heavy Cruiser | Wichita CE | 60° | 75° |
British Destroyer | Druid | 60° | 75° |
British Cruisers | Celtic, Defence | 60° | 67.5° |
Premium British Battleships | Hood, Duke of York | 60° | 67.5° |
Pan-Asian Destroyers | Fenyang, 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, New Orleans, Indianapolis, (AL) Baltimore, Anchorage, Rochester, Wichita, Buffalo, Tulsa, Salem, Congress, Alaska (B), Des Moines |
60° | 67.5° |
Italian Battleships | Andrea Doria, F. Caracciolo, V. Veneto, Lepanto | 55° | 70° |
Russian Cruiser | Dmitry Pozharsky | 55° | 70° |
Russian Cruisers | Stalingrad, Tallinn, Riga, Pyotr Bagration (B) | 55° | 65° |
Italian Battleship | C. Colombo | 50° | 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° |
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.
Rule | |
---|---|
Special Rule | German battleships' 105 mm secondary batteries: 20 mm
AL Chapayev's main batteries: 37 mm |
1/4 (Caliber ÷ 4) | British battleships' main batteries (except for Warspite (B), Hood, Collingwood and the Tiger to Duncan line)
German battleships' main batteries |
1/5 (Caliber ÷ 5) | Main batteries of Fenyang, Akizuki, Bayard, De Zeven Provinciën, 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.
SAP Penetration
As Semi-Armor Piercing shells detonate on impact, they have, just like HE shells, set penetration values.
Caliber | Armor Penetration |
---|---|
90 mm | 26 mm |
102 mm | 29 mm |
120 mm | 34 mm |
127 mm | 36 mm |
135 mm | 38 mm |
139 mm | 39 mm |
152 mm | 42 mm |
203 mm | 54 mm |
320 mm | 82 mm |
406 mm | 102 mm |
457 mm | 114 mm |
References
- ↑ Based on World of Warships PC's Wiki Page: Gunnery and Aiming
- ↑ hey_its_mojo's AP Shells table from World of Warships: Legends' official Discord server . Please note that this table can contain some mistakes.
- ↑ hey_its_mojo's HE Penetration guide from World of Warships: Legends' official Discord server