World of Warships: Legends ship guide

Z-31

Beta
Long-range gunboatOut-range peer DDs and kite cruisers; HE spam from open water.
Playstyle
  • Sit in open water at the edge of 11.6 km where peer DDs cannot return fire and most cruisers have to push to engage
  • Avoid: Idling beam-on in an obvious torpedo lane
Key characteristics
Heavy AP pen11.6 km gun rangeHeavy HE shellsWide always-pen zoneStrong AALow HE DPM
On this page
Community Data

Z-31 Community Stats

Across 4,400+ Standard battles from 220+ players, Z-31 averages a 64% win rate, 43,400 damage and 1.2 kills per battle, and survives 51% of them.

Community Data

Z-31 Community Stats

Log in to GamingDiver and upload your data to see Community Data for Z-31: community win rate, damage, survival, spotting, and your own comparison.

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Playstyle

Overview

Z-31 is a Tier VI German long-range gunboat destroyer reaching 11.6 km: her guns out-reach peer DDs and most cruisers can be kited at the edge of her range. The kit is long-range AP work from open water rather than cap contesting; the torpedoes are a backup, not the primary threat. AA (201 AA DPS at 3.5 km) ranks 3 of 41 in T6 DDs: heavy enough to make a careless strike expensive, though not the umbrella that shuts a carrier out of her grid. Standout traits: best heavy AP shells in T6 DDs (3,700, 1st of 37) and best AP overmatch threshold in T6 DDs (10.4 mm, 1st of 41). The trade is low HE DPM in T6 DDs (82,000, 38th of 41).

Positioning

Sit in open water at the edge of 11.6 km where peer DDs cannot return fire and most cruisers have to push to engage. The kit is HE pressure from distance, not cap contesting; let your peer DDs take the cap while you kite the rotating cruisers and BBs that come to support it. Shooting from the cloud gives you away at 3.1 km, and a destroyer here is spotted at about 6.9 km, so you see it coming with roughly 3.8 km to spare. Vision is mutual: past the 2 km guaranteed ring you cannot see out either, and nothing in her kit sees through it, so pop the smoke where someone is already lighting the enemy or you will sit in it with nothing to shoot. Enemy sonar (about 4.2 km) and radar (about 9 km) read straight in regardless. Both phases of a turn are slow (4.8 s on the rudder, a 670 m circle), so course changes are a plan rather than a reaction: set the angle before you are shot at.

Potato Avoidance

Idling beam-on in an obvious torpedo lane

Unspotted is not unseen: once the enemy has reason to think a destroyer is holding this cap they will put torpedoes into the water you are probably in, and one fish the size of your own (11,867 damage against 23,300 HP) takes 51% of the ship. Keep way on, cross lanes bow or stern first, and never sit still beam-on to a chokepoint you would torpedo yourself.

Signature Traits

Engine Boost

+8% speed (about +2.8 kt), 120 s duration. Engine Boost consumable gives a small speed nudge - useful for closing a gap or steadying a torpedo run, not for running anything down.

ELITE MAIN BATTERY ↗
  • Heavy AP shells · 3700 damage
  • Big-caliber AP overmatch · 10.4 mm
  • Long gun range · 11.6 km
  • Long-range AP brick · 105.82 mm
  • Close-range AP brick · 213.9 mm
High HP pool ↗

23300 HP, best of T6 DDs.

Low HE DPM ↗

82000 HE DPM, bottom decile of T6 DDs. Don't bank on burn pressure.

Easily spotted ↗

7.2 km surface detect, bottom decile of T6 DDs. Visible before you can react; position early.

Acquisition

How to get Z-31

Z-31 is available in the Hunter Destroyers branch of the Germany Tech Tree for 9,000,000 credits after researching it in the branch. Known module upgrades cost up to 2,250,000 credits. Official source cards below may also show its temporary Early Access window before it became a normal Tech Tree unlock. Container chances are shown as the listed odds of receiving this exact ship, dividing grouped ship-pool odds across the resolved ships and including nested container paths when a crate can drop another crate.

History: Early Access Dec 2023 (temporary crate drops, now ended).

While you save up, check active promo codes for free doubloons, camouflages, and other rewards.

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Best listed chance for this ship

Official WG availability sources
  • Early Access: Doubling Up Early Access Start: 2023-12-19
    • During this update, you can get these ships from French Cruiser and German Destroyer crates (these can be obtained through the campaign or Brawl Season 16, coming next year) or from dedicated random bundles.
    • German Tier VI Destroyer Z-31
Show direct source rows

Want the full picture? Each container page charts the odds as you open more crates - including pity guaranteed-reward timers and, for GD Supporters, pack math personalized to your port.

Builds

Pair with a commander whose unique skill complements her main armament; check the build tool for current recommendations.

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Have a build you swear by? Open it in the Build Tool and hit Save build to share it here, or browse the Ship Builds guide for proven loadouts across the fleet.

Cohort position

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Where Z-31 sits among Tier VI DDs (40 ships). Notable standouts are shown first; the rest of the cohort-ranked stats are in the expand below. Acquisition variants (Black Friday, Founders Edition) are counted once with their base ship, not as separate peers.

BestHit points23,300 HP (1/41) BestMain battery caliber150 mm (1 of 2 tied) BestHE fire chance12% (1 of 2 tied) BestAP shell damage3,700 (1 of 2 tied) BestMain dispersion55.5 m (1/41) LongestAP fuse timer0.025 s (1 of 4 tied) BestAP ricochet start60° (1 of 3 tied) BestAP auto-bounce angle67.5° (1 of 3 tied) BestAP pen at 10 km117 mm (1/35) BestMax armor25 mm (1/41) BestCitadel belt25 mm (1/41) Top 10%Main battery range11.57 km (2/41) Top 10%AA DPS201 (3/41) Top 25%Engine power70,000 hp (7/41) Top 25%Power / turn radius104.5 hp/m (8/41) Top 25%AA threat549 (8/41) Bottom 25%Max speed35 kt (36/41) Bottom 25%Stealth profile7.19 km / 3.6 km (37/41 / 36/41) Bottom 25%Turning circle670 m (32/41) Bottom 25%Main battery reload6 s (32/41) Bottom 25%Acceleration (0-12 kt)5.1 s (32/41) Bottom 25%Effective HE DPM (incl. fire)117,895 (37/41) Bottom 25%Torpedo range7.5 km (33/41) Bottom 25%Torpedo reaction time8.6 s (34/41) Bottom 10%Rudder shift4.8 s (38/41) Bottom 10%HE DPM82,000 (38/41) Bottom 10%Displacement3,691 t (39/41) Bottom 10%Torpedo speed52 kt (39/41) Bottom 10%Torpedo reload120 s (39/41) WorstSmoke fire bloom3.09 km (41/41) WorstNo secondaries (37 of 41 in cohort) WorstAP arming threshold25 mm (1 of 2 tied)
See 11 mid-pack stats

Not standouts for Z-31 -- here's where she sits on every other ranked stat in the cohort. Stats tagged NORM are tied across more than half the cohort, so the value is the cohort default rather than a standout.

Fires per minute4.8(21/41) AP DPM148,000(26/37) AP velocity835 m/s(17/37) HE velocity835 m/s(21/41) Time to 90% speed16.1 s(18/41) Power-to-weight18.97 hp/t(27/41) AA range3.5 km(23/41) Torpedo damage≈11,867(29/41) NormTurn speed retained81%(37 of 41 tied at this value) NormBow armor16 mm(34 of 41 tied at this value) NormStern armor16 mm(34 of 41 tied at this value)
Survivability
Hit PointsInitial: 18,500 → 23,300
Displacement3,691 t
Hull dimensions
ƒLength x beam at the waterline, plus draft. Length matters when dodging torpedoes; beam and draft shape how hard the ship is to hit.
127 x 12 m
Armor range10–25 mm
Plate armor thicknesses10, 16, 19, 25 mm
Armor material/layer entries24
Fire resistance
ƒstock hull: 1 − 0.7336 fire coefficient = 26.6%; top hull: 1 − 0.7003 fire coefficient = 30%. Lowers how often hits set you on fire. It does not reduce the damage a burning fire does per second; fires burn at the full rate on every ship.
Initial: 26.6% → 30%
Fire duration30 s
Fire damage
ƒOne unattended fire: 0.003 of max HP per second (0.3%) × 30 s = 0.09 of the pool; 0.09 × 23,300 HP = 2,097 HP on this ship. 4 fire points can burn at once.
0.3% of HP per second
Flood duration40 s
Flood damage
ƒOne unattended flood: 0.0025 of max HP per second (0.25%) × 40 s = 0.1 of the pool; 0.1 × 23,300 HP = 2,330 HP on this ship.
0.25% of HP per second
Torp Reduction
ƒ1 − 0.333 hull torpedo-damage coefficient / 0.333 unprotected baseline = 0%. Reduces torpedo hit damage. It does not affect flooding: floods start as often and tick at the full rate.
0%
Magazine HP
ƒPer-turret powder-magazine HP, a separate pool from the ship's. Penetrating hits wear it down and the turret is likelier to be knocked out as it falls, so a larger pool keeps the guns firing through punishment that silences a peer's.
10,700
Steering gear HP
ƒDurability of the steering gears. As this pool drops, hits are likelier to jam the rudder; unlike most modules the steering can be knocked out and repaired but is never permanently destroyed.
6,400
Repairable: penetration50%
Repairable: steering gear50%
Section HP
Bow section HP
ƒDamage saturation pool for the bow: penetrations here deal their normal share until twice this much penetration damage has landed on the section (2 × 2,900 = 5,800), then further hits on it deal half damage. A penetration deals 0.33 × the shell's max damage; once the section is saturated it deals exactly half of that (0.5 × 0.33 = 0.165 × max damage), so a 3,000-damage shell's pen goes from 990 to 495. Overpens (0.1 × max damage) and citadels (1.0 ×) ignore saturation. Pens on the ship's other, unsaturated sections still deal the normal 0.33 ×. A larger pool keeps that part of the ship taking full damage for longer; a small one saturates fast and protects the ship's HP.
2,900
Casemate section HP
ƒThis section has no practical saturation cap: every hit here keeps dealing its normal share of damage (on most ships the citadel; on many destroyers the casemate).
No saturation cap
Hull section HP
ƒDamage saturation pool for the hull: penetrations here deal their normal share until twice this much penetration damage has landed on the section (2 × 16,100 = 32,200), then further hits on it deal half damage. A penetration deals 0.33 × the shell's max damage; once the section is saturated it deals exactly half of that (0.5 × 0.33 = 0.165 × max damage), so a 3,000-damage shell's pen goes from 990 to 495. Overpens (0.1 × max damage) and citadels (1.0 ×) ignore saturation. Pens on the ship's other, unsaturated sections still deal the normal 0.33 ×. A larger pool keeps that part of the ship taking full damage for longer; a small one saturates fast and protects the ship's HP.
16,100
Superstructure section HP
ƒDamage saturation pool for the superstructure: penetrations here deal their normal share until twice this much penetration damage has landed on the section (2 × 1,500 = 3,000), then further hits on it deal half damage. A penetration deals 0.33 × the shell's max damage; once the section is saturated it deals exactly half of that (0.5 × 0.33 = 0.165 × max damage), so a 3,000-damage shell's pen goes from 990 to 495. Overpens (0.1 × max damage) and citadels (1.0 ×) ignore saturation. Pens on the ship's other, unsaturated sections still deal the normal 0.33 ×. The superstructure is not exempt: it saturates exactly like the bow and stern, so shells aimed at it stop dealing full damage once this pool is used up. A larger pool keeps that part of the ship taking full damage for longer; a small one saturates fast and protects the ship's HP.
1,500
Stern section HP
ƒDamage saturation pool for the stern: penetrations here deal their normal share until twice this much penetration damage has landed on the section (2 × 2,000 = 4,000), then further hits on it deal half damage. A penetration deals 0.33 × the shell's max damage; once the section is saturated it deals exactly half of that (0.5 × 0.33 = 0.165 × max damage), so a 3,000-damage shell's pen goes from 990 to 495. Overpens (0.1 × max damage) and citadels (1.0 ×) ignore saturation. Pens on the ship's other, unsaturated sections still deal the normal 0.33 ×. A larger pool keeps that part of the ship taking full damage for longer; a small one saturates fast and protects the ship's HP.
2,000
Main Battery
ModuleArtillery: 150 mm L/48 Tbts LC/36
Mounts / barrels3 mounts / 4 barrels
Reload time6 s
Firing range (base)10.5 km
Firing range (top fire control)11.6 km
Turret traverse14 °/s
Turret armor30 mm
Turret traverse arcs
ƒHow far each mount can train, in degrees to either side of the mount's own facing. A rear turret with ±150° leaves a 60° blind wedge over the bow; one-sided arcs are wing mounts that cover a single side. The data does not say which way each mount faces, so the arcs are listed per mount without bow/stern angles.
±140°, ±150°, ±145°
Guns to bear
ƒ180° − 140° (the most restricted aft-facing mount's arc) = 40° off bow; 180° − 145° (the most restricted forward-facing mount's arc) = 35° off stern. How far off the bow (or stern) the ship must angle before every main turret can fire: the widest blind wedge among the rear-facing (or forward-facing) mounts, from each mount's trainable arc.
40° off bow / 35° off stern
Shell Grouping (σ)2
Dispersion type
ƒIn practice: 45% tighter (better) horizontal dispersion and 45% less vertical spread at max range (11.6 km) than a standard destroyer: about 56 m wide × 33 m tall, against 102 m × 61 m. Also on this curve (5): Elbing, Felix Schultz, Gustav Julius Maerker, Sovremenny, Tiger '59.
Pinpoint destroyer
Max Horiz Disp
ƒHorizontal dispersion ellipse width at max range, from the dispersion model: σH=(R30·idealRadius−minRadiusidealDistance+minRadius)·30 =(1157230·4−0.51000+0.5)·30=55.5m
55.5 m at 11.6 km
Max Vert Disp
ƒVertical dispersion ellipse height at max range: σV=σH·radiusOnMax =55.5·0.6=33.3m
33.3 m at 11.6 km
Med Horiz Disp
ƒ50%-hit horizontal radius: σH,50=σH·0.6σ =55.5·0.62=16.7m
16.7 m at 11.6 km
Med Vert Disp
ƒ50%-hit vertical radius: σV,50=σV·0.6σ =33.3·0.62=10m
10 m at 11.6 km
Turret turn time
ƒ180 degrees / 14 deg/s traverse speed = 12.9 s.
12.9 s
Shells/min
ƒ4 broadside guns x 60 / 6 s base reload = 40.
40
HE shells
HE alpha2,050
HE Velocity835 m/s
Fire Chance12%
HE fire DPM vs T6 BB35895
Effective HE DPM vs T6 BB117895
HE penetration
ƒ38 mm ≈ 150 mm caliber / 4 (improved HE penetration: German BBs, Yamato-class, and a handful of others).
38 mm
HE full-salvo alpha
ƒ2,050 HE damage x 4 broadside guns = 8,200.
8,200
HE DPM
ƒ8,200 HE full-salvo alpha x 60 / 6 s base reload = 82,000.
82,000
Fires/min
ƒ40 shells/min × 0.12 (12% fire chance) = 4.8.
4.8
AP shells
AP alpha3,700
AP Velocity835 m/s
Min Ricochet60 deg
Guaranteed Ricochet67.5 deg
Fuse Timer0.025 s
Fuse Threshold25 mm
AP overmatch
ƒfloor(150 mm caliber / 14.3) = 10 mm (AP auto-penetrates plating this thick or less).
10 mm
AP Pen Close
ƒAP formula evaluated at muzzle velocity: P=10−7·K·m0.69·d−1.07·v01.38 =10−7·1933·510.69·0.15−1.07·8351.38=238.8mm.
238.8 mm point-blank
AP Pen Far
ƒSame formula at the ship's max firing range (11.6 km), where the shell has slowed to 463 m/s: P=10−7·1933·510.69·0.15−1.07·4631.38=105.8mm.
105.8 mm at 11.6 km
AP full-salvo alpha
ƒ3,700 AP damage x 4 broadside guns = 14,800.
14,800
AP DPM
ƒ14,800 AP full-salvo alpha x 60 / 6 s base reload = 148,000.
148,000
AP AOE Radius
ƒAP shell over-penetration splash radius; scales with shell mass. Wickes 102mm = 3, standard 152mm CL ~ 20, Iowa 406mm ~ 270, Yamato 460mm = 400, Incomparable 650mm = 550 (max). Larger value = bigger splash damage area when AP over-pens.
15
Torpedoes
ModuleTorpedoes: 533 mm Vierling
Launchers / tubes2 launchers × 4 tubes = 8 tubes
Reload time120 s
Projectile speed52.0 kt
Range7.5 km
Maximum simulated damage
ƒMost targets only intersect one hull section, so a hit transfers about 1/3 of the warhead alpha (2/3 when the warhead blast >= 5000 and the burst reaches a second section). For this ship: Dsim=α·c=35,600·0.333=11,867. In battle, a hit on the torpedo belt deals the per-hit figure × (1 − the target's torpedo protection %), a bow or stern hit deals it in full, and a torpedo never counts as a citadel hit.
≈ 11,867
Maximum damage (ammunition)
ƒ35,600 warhead alpha / 3 + 1,000 blast = 12,867. Warhead alpha / 3 plus the blast addend: the per-torpedo damage figure. The 'Maximum simulated damage' row above applies target geometry to the same warhead.
12,867
Torpedo module damage
ƒPer-torpedo module/blast damage parameter. Most torpedoes carry 500 to 2,000; ships announced by WG as dealing increased module damage carry 9,000 to 12,000, so their hits knock out engines, rudders, and turrets far more often. Comparative figure.
1,000
Torpedo detectability1.2 km
Reaction time
ƒHow long a target has to dodge after your torpedo is spotted at its detectability range (lower means less warning): treact=1.2 km52 kt×2.6855=8.6 s. 2.6855 converts knots to m/s on the game clock. Base value; commander torpedo-concealment skills lower it further.
8.6 s
Flooding chance
ƒThis torpedo carries a flooding-chance value of 2.27 per hit, shown as 2.27×100=227%. Values above 100% are normal: in battle the base chance is scaled down by the target's torpedo protection (the Torp Reduction stat on its Survivability card) and any flood-resistance modifiers, so a value above 100% keeps flooding likely even through partial protection.
227%
Torpedo launcher traverse25 °/s
Launch arcscentreline 260°, 262°
Torp Turn
ƒTime to rotate the launchers 180 deg: tturn=180°25°/s=7.2s.
7.2 s
Torp Arming170 m
Per-side salvo damage
ƒOne side firing, all torpedoes hitting: per-side tubes x per-torpedo simulated damage = 8 x 11,867 = 94,936. Each hit on the target's torpedo belt is reduced by its torpedo protection %.
94,936
AA Defense
AA mount points12
Maximum AA range
ƒLongest-reaching family on the in-game AA card. Base AirDefense aura max range is 3.5 km; dual-purpose mount auras extend it.
3.5 km
37 mm Flak LM/42Initial: 37 mm Flakzwilling 30 (4×2) → 37 mm Flak LM/42 (4×2)
20 mm Flakvierling 38 (upgraded hull only)2×4 20mm
20 mm Flakzwilling 38 (upgraded hull only)6×2 20mm
20 mm Flak 38 (stock hull only)8×1 20mm
Medium aura
Guns37 mm Flak LM/42
Continuous DPS
ƒInitial: 9 × 3.5 × 1 = 32 → 28 × 3.5 × 1 = 98. Raw aura damage × 3.5 × hit probability, the same in-game units as the Close-range AA DPS headline.
Initial: 32 → 98
Range3.5 km
Near aura
Guns20 mm Flakvierling 38 + 20 mm Flakzwilling 38
Continuous DPS
ƒInitial: 24 × 3.5 × 0.95 = 80 → 31 × 3.5 × 0.95 = 103. Raw aura damage × 3.5 × hit probability, the same in-game units as the Close-range AA DPS headline.
Initial: 80 → 103
Range2 km
Total DPS in Aura
ƒMedium 98 + Near 103 = 201
201
Maneuverability
Engine power70,000 hp
Maximum speed35.0 kt
Turning circle radius670 m
Rudder shift timeInitial: 7.3 s → 4.8 s
Engine power-boost threshold7.0 kt
Engine spool-up time7.7 s
Reverse spool-up time3.8 s
Reverse speed
ƒtop speed / 4 + 4.9 = 35 / 4 + 4.9 = 13.7 kt. Base value; speed modifiers scale it.
13.7 kt
Crash stop
ƒSeconds from top speed to a dead stop after ordering full reverse: reverse power winds in over the reverse spool-up while water drag does most of the braking, using the ship's own reverse-power ratio. The full curve is on the acceleration chart. Full reverse stops about a quarter faster than a plain Stop order from top speed.
14.9 s
Engine boost threshold (reverse)
ƒSpeed below which the engine's built-in power boost applies in reverse.
10.0 kt
Acceleration 0-90%
ƒTime to reach 90% of top speed (31.5 kt of 35.0 kt).
16.1 s
Acceleration 0-99%
ƒTime to reach 99% of top speed (34.6 kt of 35.0 kt). 99% rather than 100% because true top speed is asymptotic (thrust meets drag), so the last fraction of a knot is never quite gained.
26.8 s
Guns in a full turn
ƒWith the rudder hard over the hull turns 6.9°/s, so a target drifts across the bow at that rate. Turret traverse minus hull turn: 14 − 6.9 = +7.1°/s, so the guns hold the target through the turn. Main Battery Mod. 2 (+20% traverse) and Mod. 3 (−15%) move this line.
hold target (+7.1°/s spare)
Concealment
Detectability by sea
ƒBase value, no camouflage. With a Grade IV permanent camo (or any disposable camo): 7.19 km x 0.955 = 6.87 km. Camouflage does not change detectability by air.
7.19 km
With Grade IV camouflage (sea)
ƒDetectability by sea 7.19 km x 0.955 (Grade IV permanent camo or any disposable camo) = 6.87 km.
6.87 km
Detectability by air3.6 km
Smoke firing penalty3.09 km
Detect when firing (sea)
ƒmax(main battery range, sea detectability 7.19 km) = 11.57 km. Equal to the ship's main battery range (never below base detectability): firing makes you visible to everyone you can reach.
11.57 km
Detect when firing (air)
ƒAir detectability 3.6 km + gun-firing bloom 3 km = 6.6 km. The bloom tracks main-battery caliber 150 mm × 0.020 = 3 km.
6.6 km
Detect when on fire (sea)
ƒSea detectability 7.19 km + 2.0 km while burning = 9.19 km.
9.19 km
Detect when on fire (air)
ƒAir detectability 3.6 km + 3.0 km while burning = 6.6 km.
6.6 km
Guaranteed Detect2 km
✦
Consumables
Damage Control Party∞ charges · 40 s reload · 5 s active
Smoke Generator2 charges · 240 s reload · 20 s emit / 65 s cloud active · 450 m radius
Engine Boost2 charges · 180 s reload · 120 s active · +8% speed bonus
Module options (3)

Stats above use the fully-upgraded modules. These are the research-tree alternatives; trade-offs are flagged.

HullUpgrade
  • Hit points18,500 → 23,300
  • Rudder shift7.3 → 4.8 s
  • Close-range AA DPS33 → 59
Fire controlUpgrade
  • Main battery range10,520 → 11,572 m
EngineUpgrade
  • Time to 12 kt5.7 → 5.1 s

Under the hood

Show ▾

All values are ship base stats with modifications and upgrade changes denoted inline.

The constants behind the formulas and the long tail: shell and dispersion inputs, fixed-range anchors, salvo math, layered AA. Click the formula chip on any row to see how it is calculated.

Main battery formulas

vs standard DD45% tighter H · 45% shorter V
H = horizontal, V = vertical spread. This ship's curve against the standard destroyer curve, both evaluated at this ship's max range (11.6 km) with the same model as Max Horiz/Vert Disp: horizontal 56 / 102 m − 1 = -45%, vertical 33 / 61 m − 1 = -45%. Shell grouping (σ) is separate: it sets how shells bunch toward the centre of this ellipse.
Shell scatter width @ 5 km32.5 m
(166.7 × (4 − 0.5) / 1000 + 0.5) × 30 = 32.5 m. Horizontal scatter at a fixed 5 km, from the same dispersion model as the rows below - a knife-fight-range anchor comparable across ships.
Shell scatter width @ 10 km50 m
(333.3 × (4 − 0.5) / 1000 + 0.5) × 30 = 50 m. How wide your shells scatter at 10 km, from the same dispersion model as the max-range figure above. Picking a fixed range makes this number directly comparable from ship to ship: max-range dispersion makes a longer-range gun look worse even when it's tighter at any common range. The interactive Dispersion tab on the Charts card plots the full curve from 0 to max range.
Shell scatter height @ 5 km14.9 m
How tall the scatter ellipse is at a fixed 5 km, from the same model, comparable from ship to ship. The height/width ratio is a piecewise-linear curve through three points from the ship's own dispersion data: radiusOnZero=0.2 at 0 m, radiusOnDelim=0.5 at delim·Rmax=0.5·11572=5786 m, and radiusOnMax=0.6 at 11572 m. Below the kink: k=0.2+(0.5−0.2)·50005786=0.4592, so σV=σH·k=32.5·0.4592=14.9m.
Shell scatter height @ 10 km28.6 m
How tall the same scatter ellipse is at 10 km. Comparable from ship to ship for the same reason as the width value above. The height/width ratio is a piecewise-linear curve through three points from the ship's own dispersion data: radiusOnZero=0.2 at 0 m, radiusOnDelim=0.5 at delim·Rmax=0.5·11572=5786 m, and radiusOnMax=0.6 at 11572 m. Above the kink: k=0.5+(0.6−0.5)·10000−578611572−5786=0.5728, so σV=σH·k=50·0.5728=28.6m.
AP pen 5 km166 mm
AP penetration at a fixed 5 km, from the same ballistic curve as AP Pen Close/Far: the shell's impact velocity at that range fed through the AP formula P=10−7·K·m0.69·d−1.07·v1.38 =10−7·1933·510.69·0.15−1.07·640.91.38=166mm, where 640.9 m/s is the shell's speed when it arrives at 5 km (from 835 m/s at the muzzle). Fixed anchors make ships directly comparable at the same fighting distance; the Charts card plots the full curve.
AP pen 10 km117 mm
AP penetration at a fixed 10 km, from the same ballistic curve as AP Pen Close/Far: the shell's impact velocity at that range fed through the AP formula P=10−7·K·m0.69·d−1.07·v1.38 =10−7·1933·510.69·0.15−1.07·4981.38=117mm, where 498 m/s is the shell's speed when it arrives at 10 km (from 835 m/s at the muzzle). Fixed anchors make ships directly comparable at the same fighting distance; the Charts card plots the full curve.
AP flight time @ 10 km5.71 s
How long an AP shell takes to reach a target at a fixed 10 km, from the same numerically integrated trajectory the Charts card plots. The shell slows under quadratic air drag, adrag=kρv2, where ρ is air density from a standard-atmosphere profile and k bundles the shell's drag coefficient, caliber and mass: k=πCdd28m=π·0.25·0.1528·51=4.33×10−5. That runs from a 835 m/s muzzle velocity in 0.02 s steps under gravity 9.8 m/s² until the shell lands, then divides by 2.77 because the game clock runs faster than real time. Lower is better, since a faster shell is harder to dodge and needs less lead.
HE flight time @ 10 km5.71 s
How long an HE shell takes to reach a target at a fixed 10 km, from the same numerically integrated trajectory the Charts card plots. The shell slows under quadratic air drag, adrag=kρv2, where ρ is air density from a standard-atmosphere profile and k bundles the shell's drag coefficient, caliber and mass: k=πCdd28m=π·0.25·0.1528·51=4.33×10−5. That runs from a 835 m/s muzzle velocity in 0.02 s steps under gravity 9.8 m/s² until the shell lands, then divides by 2.77 because the game clock runs faster than real time. Lower is better, since a faster shell is harder to dodge and needs less lead.
Improved HE PenYes
This ship's HE shells use a 1/4 (~0.25) caliber-to-pen ratio instead of the standard 1/6 (~0.167) - 0.253 in this case. Lets HE pen ~37mm armor instead of ~25mm. Hits every German cruiser (150mm CL, 203mm CA) and BB (350mm+), British heavy cruisers / Lion / Nelson, a handful of other premiums.
Guns per full salvo (alpha, DPM)4
3 mounts × 1.33 barrels = 4; all 4 bear on the broadside.

Model inputs

Krupp (AP)1,933
Armor-penetration constant of the AP shell; penetration scales straight with it, so a 10% higher Krupp is 10% more penetration at every range.
AP shell mass51 kg
Enters penetration as mass^0.69 and slows the shell's drag deceleration, so a heavier shell keeps more velocity at range.
AP drag coefficient0.25
Air drag on the AP shell in flight; lower keeps velocity, and with it penetration, at long range.
AP muzzle velocity835 m/s
Starting speed of the AP shell; penetration scales with velocity^1.38.
HE muzzle velocity835 m/s
Starting speed of the HE shell; sets its flight time and lead.
idealRadius4
Horizontal dispersion growth per idealDistance of range, in 30 m units; the slope of the scatter-width line.
minRadius0.5
Horizontal dispersion at zero range, in 30 m units; the intercept of the scatter-width line.
idealDistance1,000 m
Range step over which horizontal dispersion grows by idealRadius.
taperDist4,000 m
Inside this range the scatter width tapers toward minRadius instead of following the line.
radiusOnZero0.2
Vertical scatter as a share of horizontal at zero range.
radiusOnDelim0.5
Vertical scatter as a share of horizontal at the delim point.
radiusOnMax0.6
Vertical scatter as a share of horizontal at maximum range.
delim0.5
Where the vertical-scatter curve bends, as a share of maximum range.

Torpedoes

Estimated torpedo reaction time8.6 s
1200 m / (52.0 kt × 2.6855) = 8.6 s. detectability / (speed kt x 2.6855 m/s per knot on the game clock).
Torpedo speed52.0 kt
Travel time to max range53.7 s
7500 m / (52.0 kt × 2.6855) = 53.7 s. range / (speed kt x 2.6855 m/s per knot on the game clock).
Tube count8
2 launchers × 4 tubes.
Per-side salvo8 torpedoes
2 launchers × 4 tubes = 8, all to either side (centreline launchers train across - full salvo to either side).
Full-salvo damage94,936
All tubes hitting one target: tubes x per-torpedo simulated damage = 8 x 11,867 = 94,936. Each hit on the target's torpedo belt is reduced by its torpedo protection %.

AA defense

AA DPS at max range98
Only families that reach 3.5 km contribute at the outer edge of the AA bubble. In-game families: 37mm Flak M42 Zwilling 4x2 -> 98 DPS @ 3.5 km; 20mm Flack 38 quad 2x4 -> 26 DPS @ 2 km; 20mm Flak 38 6x2 -> 77 DPS @ 2 km.
AA DPS layered by range98 DPS @ 3.5 km, 201 DPS @ 2 km
@ 3.5 km: 98 from one family; @ 2 km: 98 + 26 + 77 = 201. Cumulative AA DPS at each family range threshold. Inner ranges stack the outer families, so a target closing the distance hits stronger AA bubbles as it crosses each band.
AA DPS at point-blank201
98 + 26 + 77 = 201 DPS: the sum of every family's average DPS, achievable only inside the closest-range family (2 km).
AA threat index549
98 × 3.5 + 26 × 2 + 77 × 2 = 549. SUM over AA auras of (aura DPS x aura range km). A plane crossing the AA bubble is exposed to each aura for a time proportional to that aura's range, so long-reach DPS is worth more than the same DPS in a short bubble. Units: DPS*km; used to rank overall AA threat across the cohort.
Near aura range2 km
Open in Charting Tool

Ship Charts

Background

Following a halt to its construction, part of the 1936B destroyer class was laid down again in 1940 and 1941. The new 1936A(Mob) class was armed with 5.9-inch (150 mm) guns. Z-31, the lead ship of the class, was commissioned in April 1942. She saw action in the Barents Sea, where she fought convoy JW-51B, participated in a raid on Svalbard, and carried German troops from Finland to Norway in 1944. The ship suffered heavy damage in an encounter with British cruisers in January 1945. After the war, she was handed over to France and renamed Marceau.

Armor Beta

Hull HP 18,500 → 23,300 with hull upgrade, distributed across 5 hull zones, each with its own plate thicknesses, saturation cap, and pen thresholds.

Bow & stern16 mm

Overmatched by 126+ AP guns across the bracket. Can’t reliably bow-tank; gets bow-citadelled and overpenned.

Farming16 mm

Superstructure and extremities take HE pens and AP overpens from nearly any gun: steady chip damage. Fire resistance 30%, fires burn 30s. Range-by-range in the Compare tool →

Section Plates HP cap Threats Tactic
Bow16 mm primary (range 16–19 mm)2,900 (12% of HP)
Overmatched by 283mm+ AP (Graf Spee, Scharnhorst)Angle bounces 203mm16 mm: HE pens from 127mm+
Bow-tank fits behind this exterior plate. Saturation is FAST here; the cap is often only a few thousand HP.
Hull (midship)16 mm16,100 (69% of HP)
Overmatched by 283mm+ AP (Graf Spee, Scharnhorst)Angle bounces 203mm16 mm: HE pens from 127mm+
Largest HP pool. Citadel sits behind these plates; thinner deck and side plating absorb the rest.
Stern16 mm primary (range 16–19 mm)2,000 (9% of HP)
Overmatched by 283mm+ AP (Graf Spee, Scharnhorst)Angle bounces 203mm16 mm: HE pens from 127mm+
Mirror of bow. Same fast saturation.
Citadel25 mm primary (range 10–25 mm)≈ 165,500 (effectively no cap)
Citadel pen: full damageOver-pen: ×0.10 damage
Effectively no cap; citadel pool sits at ~165k HP on every ship. An AP citadel penetration deals the shell's full damage, the biggest single hit available; only over-penetrations are damped, to ×0.10.
Turret (module, per magazine)separate HP pool, does not drain ship HP10,700 magazine HPTurret knocked outPer-turret powder-magazine HP, a separate pool that does not drain ship HP. As it is worn down the turret is likelier to be knocked out, and a smaller pool gets there faster.
AA mount (37 mm mount)separate HP pool, does not drain ship HP200 per-mount HPDestroyed at 0 HPPer-mount HP for the heaviest AA on this ship. An AA mount destroyed at 0 HP stops shooting down planes for the rest of the battle; DCP does not repair destroyed mounts. HE shells specifically target AA mounts since the small-caliber HP pool falls fast.
Engine (module, research)engine coefficient (unconfirmed)-0.100 research estimateLargest on BB/BC; zero on destroyersEngine durability isn't a per-ship value. This small negative coefficient is non-zero only on battleships, battlecruisers, and the heaviest cruisers, and is exactly zero on every destroyer, so it scales with hull displacement rather than any commander skill. Most likely an engine drag or power term in the same family as the deceleration stats; its exact meaning is not yet confirmed.
Rudder (module)separate HP pool, does not drain ship HP6,400 module HPIncapacitated at 0 HPWhen module HP reaches 0 the rudder locks at its current angle until DCP repairs it. Repair via Damage Control Party.

Saturation cap = HP a section can absorb before further damage to it is reduced (the "bow-tank" effect). Citadel pool is ~165k on every ship (effectively no cap); damage is gated by pen/over-pen multipliers instead. Superstructure saturates fast but HE always pens regardless of the plate thickness. Rudder (and other module HPs) are a separate pool from ship HP: damaging a module doesn't drain ship HP. Incapacitated modules like the rudder and engine are restored by DCP, but secondary and AA mounts destroyed at 0 HP stay out for the rest of the battle.

Balance History

Balance updates affecting Z-31. Cards are condensed; use each source link for full context.

Nerf ×1Buff ×1Main Battery ×2
2026-07-30

Ministry of Balance: Anniversary Tune-Up

  • HE shell maximum damage increased from 1,800 to 2,050.
Read the full official post
2025-11-27

Holiday Update: Christmas on the Waves

  • Main battery reload time increased from 5.5 to 6.0 seconds.
Read the full official post
Exteriors

Skins & permanent camouflages

Every custom exterior Z-31 can equip.

  • Z-31 default exterior
    DefaultThe ship’s standard exterior

Primary official WG sources

Filtered to official World of Warships: Legends pages where this ship is a focus, reward, line member, or high-context variant mention.