World of Warships: Legends ship guide

Grom

Also called: 雷霆 Beta
Pan-Europe · Tier VI · Destroyer · Tech Tree
Torpedo destroyerBuilt around the torpedo battery: flood lanes with fish and avoid stand-up gun fights.
Playstyle
  • Sit at the edge of a contested cap from concealment and cycle torpedo waves into lanes the enemy has to…
  • Avoid: Holding 7.5-km torpedoes for a perfect shot
Key characteristics
Improved HE penSmokeEngine BoostHigh fire chanceQuick accelerationWeak torpedoes
Related variants

Grom variants in WoWs Legends

These ships share a base hull or event lineage with Grom, but GamingDiver keeps their community stats and ship pages separate when the in-game identity, nation, tier, or premium context differs.

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Community Data

Grom Community Stats

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Playstyle

Overview

Grom is a Tier VI European torpedo destroyer reaching 7.5 km. The torpedoes travel at 72 kt, so target reaction time is short - but WG builds her as a gun-and-torpedo hybrid: four hard-hitting HE guns provide the steady damage while the quick, short-lane torpedoes punish anyone who closes. Standout traits: top-decile HE fire chance in T6 DDs (9) and top-decile quick acceleration in T6 DDs (8 s).

Positioning

Sit at the edge of a contested cap from concealment and cycle torpedo waves into lanes the enemy has to use - 7.5 km reach at 72 kt means the wall arrives before targets can react. Drop on probable lanes from cover, stay unspotted between waves, and let the wall do the work. With only HE, aim at superstructures and upper-hull sections where it does full damage instead of shattering on heavy belt armor.

Potato Avoidance

Holding 7.5-km torpedoes for a perfect shot

The kit pays out by saturating lanes, not by waiting for guaranteed broadsides; missed waves still force rotations and protect your team's flank. Idle torpedo tubes are the worst output state.

Signature Traits

Improved HE penetration

HE pen at the 1/4 caliber ratio instead of the standard 1/6. HE-spam is a real damage option here, not just a fire-starter; pens roughly 1.5x more armor than a same-caliber peer's HE, shared by 5/41 T6 DDs.

Engine Boost

+5% speed, 100 s duration. Engine Boost consumable temporarily raises top speed. Mobility on demand to reposition, chase a kill, or break contact.

High fire chance

9.0% fire chance per HE shell, top decile of T6 DDs.

ELITE MOBILITY
  • Quick acceleration
  • Fast for the class · 41.0 kt
Fast torpedoes

72.0 kt torpedo speed, top decile of T6 DDs. Less reaction time for targets to dodge.

WEAK TORPEDOES
  • Weak torpedoes · 6833.0 damage
  • Visible torps · 1.6 km
Acquisition

How to get Grom

Grom is a Tech Tree ship. The normal acquisition path is researching and purchasing it in its nation/class line. 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.

Best listed chance for this ship

Official WG availability sources
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 Fleet Members, pack math personalized to your port.

Builds Beta

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

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Cohort position

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Where Grom sits among Tier VI DDs (41 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.

Top 10%Max speed41 kt (5/41) Top 10%Acceleration8 s (3/41) Top 10%Turn speed retained95.1% (2/41) Top 10%Torpedo speed72 kt (5/41) Top 25%Rudder shift3.2 s (11/41) Top 25%HE shell damage1,900 (11/41) Top 25%Fires per minute5.82 (10/41) Top 25%Main dispersion87.8 m (9/41) Top 25%HE velocity900 m/s (9/41) Top 25%Torpedo reload75 s (11/41) Bottom 25%Main battery caliber120 mm (33/41) Bottom 25%Main battery reload6.5 s (34/41) Bottom 25%Displacement3,383 t (32/41) Bottom 25%Torpedo range7.5 km (33/41) Bottom 10%Power-to-weight15.96 hp/t (39/41) WorstNo secondaries (37 of 41 in cohort) WorstTorpedo damage≈6,833 (1 of 2 tied)
See 17 mid-pack stats

Not standouts for Grom -- 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.

Hit points15,500 HP(21/41) Concealment6.9 km(21/41) Air detection3.45 km(20/41) Traverse-to-turn ratio5.05 ×(31/41) Main battery range10.67 km(19/41) HE DPM122,769(17/41) Engine power54,000 hp(17/41) Turn-speed retention88.5 hp/m(20/41) Effective HE DPM (incl. fire)166,292(17/41) AA DPS131(28/41) AA range3.5 km(23/41) AA threat358(27/41) Deck armor16 mm(14/27) NormMax armor16 mm(26 of 41 tied at this value) NormCitadel belt16 mm(28 of 39 tied at this value) NormBow armor16 mm(32 of 39 tied at this value) NormStern armor16 mm(32 of 39 tied at this value)
Survivability
Hit PointsInitial: 12,900 → 15,500
Displacement3,383 t
Armor range6–16 mm
Plate armor thicknesses6, 10, 15, 16 mm
Armor material/layer entries21
Fire resistanceInitial: 26.6% → 30%
Fire duration30 s
Torp Reduction0%
Main Battery
ModuleArtillery: 120 mm wz. 34/36 Bofors double
Mounts / barrels4 mounts / 7 barrels
Reload timeInitial: 7 s → 6.5 s
Firing range (base)9.7 km
Firing range (top fire control)10.7 km
Turret traverseInitial: 10 °/s → 12 °/s
HE fire DPM vs T6 BB43488
Effective HE DPM vs T6 BB166257
Shell Grouping (σ)2
Max Horiz Disp
ƒHorizontal dispersion ellipse width at max range, from the verified WoWS dispersion model: σH=(R30·idealRadiusminRadiusidealDistance+minRadius)·30 =(970030·80.51000+0.5)·30=87.8m
87.8 m
Max Vert Disp
ƒVertical dispersion ellipse height at max range: σV=σH·radiusOnMax =87.8·0.6=52.7m
52.7 m
Med Horiz Disp
ƒ50%-hit horizontal radius: σH,50=σH·GetHalfHitsRatio(σ) =87.8·0.319(σ=2)=28m
28 m
Med Vert Disp
ƒ50%-hit vertical radius: σV,50=σV·GetHalfHitsRatio(σ) =52.7·0.319(σ=2)=16.8m
16.8 m
Turret turn time
ƒ180 degrees / 10 deg/s traverse speed = 18 s.
18 s
Shells/min
ƒZero upgrades: 7 broadside guns x 60 / 7 s base reload = 60. All upgrades (top gun): 7 broadside guns x 60 / 6.5 s all-upgrades reload = 64.6.
Initial: 60 → 64.6
HE shells
HE Damage1,900
HE Velocity900 m/s
Fire Chance9%
HE penetration
ƒ30 mm ≈ 120 mm caliber / 4 (improved HE penetration: German BBs, Yamato-class, and a handful of others).
30 mm
HE full-salvo alpha
ƒ1,900 HE damage x 7 broadside guns = 13,300.
13,300
HE DPM
ƒZero upgrades: 13,300 HE full-salvo alpha x 60 / 7 s base reload = 114,000. All upgrades (top gun): 13,300 HE full-salvo alpha x 60 / 6.5 s all-upgrades reload = 122,769.
Initial: 114,000 → 122,769
Fires/min
ƒZero upgrades: 60 shells/min x 9% fire chance = 5.4. All upgrades (top gun): 64.6 shells/min x 9% fire chance = 5.82.
Initial: 5.4 → 5.82
AP shells
Min Ricochet91 deg
Guaranteed Ricochet60 deg
AP overmatch
ƒfloor(120 mm caliber / 14.3) = 8 mm (AP auto-penetrates plating this thick or less).
8 mm
Torpedoes
ModuleTorpedoes: 533 mm triple
Launchers / tubes2 launchers × 3 tubes = 6 tubes
Reload time75 s
Projectile speed72 kt
Range7.5 km
Maximum simulated damage
ƒEstimate of WG's in-game value; matches the in-game port screen within ±5%. Saturation: most targets only intersect one hull section, so the sim transfers ~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=20,500·0.333=6,833.
≈ 6,833
Maximum damage (ammunition)
ƒThe ammunition card's 'Maximum Damage' stat, exact: warhead alpha / 3 plus the blast addend. This is the per-torpedo number most references quote; the 'Maximum simulated damage' row above is WG's separate geometry-sim stat from the launcher spec panel.
7,533
Torpedo detectability1.6 km
Reaction time
ƒHow long a target has to dodge after your torpedo is spotted at its detectability range (lower means less warning): treact=1.6 km72 kt×2.6=8.5 s, equivalently 5000×detectability/(13×speed). Base value; commander torpedo-concealment skills lower it further. Community torpedo-reaction calculator by u/LorenDovah and u/The_ColorOutofSpace.
8.5 s
Flooding chance
ƒRead straight from the game's own data: this torpedo carries a flooding-chance value of 1.19 per hit, shown as 1.19×100=119%. Torpedo flood 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. Not shown on the in-game port screen.
119%
Torpedo launcher traverse25 °/s
Torp Turn
ƒTime to rotate the launchers 180 deg: tturn=180°25°/s=7.2s.
7.2 s
Torp Arming222 m
Per-side salvo damage
ƒOne side firing, all torpedoes hitting: per-side tubes x per-torpedo simulated damage = 6 x 6,833 = 40,998.
40,998
AA Defense
AA mount points6
Close-range AA DPS
ƒSum across every AA aura on this ship of (aura.continuous_damage x 3.5 x aura.hit_probability). Here: (25×3.5×1) + (13×3.5×0.95) = 131. Covers AA-only mounts plus dual-purpose secondaries (Bismarck 105mm, USN 5"/38 cruiser secondaries) and dual-purpose main batteries (Sumner-class 5"/38, Akizuki-line 100mm). Formula validated against in-game captures on California, Sumner, Manfred von Richthofen, Dante Alighieri (exact) and within +/-17% on the remaining verified ships. Flak is NOT included: flak stops triggering once planes are inside 2.5 km, and its avoidable burst damage is shown separately in the Flak bursts section.
131
Maximum AA range
ƒLongest-reaching aura across AA-only + dual-purpose auras.
3.5 km
40 mm/56 Bofors № 3Initial: 40 mm/60 Bofors M1936 (2×1) → 40 mm/56 Bofors № 3 (2×2)
13.2 mm Hotchkiss wz. 304×2 13mm
Medium aura
Guns40 mm/56 Bofors № 3
Continuous DPS
ƒEffective DPS: 25 raw aura damage × 3.5 × 1 hit probability = 88 - the same in-game units as the Close-range AA DPS headline.
Initial: 49 → 88
Range3.5 km
Near aura
Guns13.2 mm Hotchkiss wz. 30
Continuous DPS
ƒEffective DPS: 13 raw aura damage × 3.5 × 0.95 hit probability = 43 - the same in-game units as the Close-range AA DPS headline.
Initial: 50 → 43
Range1.2 km
Total DPS in Aura
ƒMedium 88 + Near 43 = 131
131
Maneuverability
Engine power54,000 hp
Maximum speed41 kt
Turning circle radius610 m
Rudder shift time3.2 s
Engine power-boost threshold39 kt
Engine spool-up time7.7 s
Reverse spool-up time3.8 s
Acceleration 0-90%
ƒTime to reach 90% of top speed (36.9 kt of 41 kt), from our in-house acceleration model.
8 s
Acceleration 0-99%
ƒTime to reach 99% of top speed (40.6 kt of 41 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.
19 s
Traverse-to-turn ratio
ƒHow many degrees the turret can swing for each degree the hull turns. Turn rate ωhull=180π·Vmax(m/s)Rturn=180π·41.0·0.5144610=1.98°/s, so ratio=ωturretωhull=101.98=5.0×. Below 5 the turrets drag in a turning fight; 25+ keeps up with any rudder.
5.0× slow
Concealment
Detectability by sea6.9 km
Detectability by air3.45 km
Smoke firing penalty2.45 km
Detect after firing main guns
ƒmax(base sea detectability, gun-firing bloom range). Firing never pulls your detection closer than base concealment.
6.9 km
Detect Fire Sea8.9 km
Detect Fire Air6.45 km
Guaranteed Detect2 km
Consumables
Damage Control Party∞ charges · 40 s reload · 5 s active
Smoke Generator2 charges · 240 s reload · 20 s emit / 85 s cloud active · 450 m radius
Choose one
Engine Boost2 charges · 160 s reload · 100 s active · +5% speed bonus
Defensive AA Fire3 charges · 140 s reload · 25 s active · ×3 flak burst boost
ƒRepeats the flak burst pattern ×3 within each wave - more clouds in the air over the wave, at the same spots.
Module options (3)

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

HullUpgrade
  • Hit points12,900 → 15,500
  • Rudder shift6.5 → 4.2 s
  • Close-range AA DPS29 → 38
  • Turret traverse10 → 12 °/s
Fire controlUpgrade
  • Main battery range9,700 → 10,670 m
ArtilleryUpgrade
  • Base reload7 → 6.5 s

See all derived stats

Show

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

Numbers the spec table cannot show directly: alpha-strike math, DPM, dispersion, AP penetration. Click the formula chip on any row to reveal how it is calculated.

Main battery formulas

Shell Grouping (σ)2
Max Horiz Disp87.8 m
Horizontal dispersion ellipse width at max range, from the verified WoWS dispersion model: σH=(R30·idealRadiusminRadiusidealDistance+minRadius)·30 =(970030·80.51000+0.5)·30=87.8m
Shell scatter width @ 5 km52.5 m
Horizontal scatter at a fixed 5 km, from the same verified dispersion model as the rows below - a knife-fight-range anchor comparable across ships.
Max Vert Disp52.7 m
Vertical dispersion ellipse height at max range: σV=σH·radiusOnMax =87.8·0.6=52.7m
Med Horiz Disp28 m
50%-hit horizontal radius: σH,50=σH·GetHalfHitsRatio(σ) =87.8·0.319(σ=2)=28m
Med Vert Disp16.8 m
50%-hit vertical radius: σV,50=σV·GetHalfHitsRatio(σ) =52.7·0.319(σ=2)=16.8m
HE penetration30 mm
30 mm ≈ 120 mm caliber / 4 (improved HE penetration: German BBs, Yamato-class, and a handful of others).
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) - 0.25 in this case. Lets HE pen ~30mm armor instead of ~20mm. Hits every German cruiser (150mm CL, 203mm CA) and BB (350mm+), British heavy cruisers / Lion / Nelson, a handful of other premiums.
AP overmatch8 mm
floor(120 mm caliber / 14.3) = 8 mm (AP auto-penetrates plating this thick or less).
Broadside guns used for alpha7
All 7 barrels bear on the broadside.
Turret turn time18 s
180 degrees / 10 deg/s traverse speed = 18 s.
HE full-salvo alpha13,300
1,900 HE damage x 7 broadside guns = 13,300.
HE DPMInitial: 114,000 → 122,769
Zero upgrades: 13,300 HE full-salvo alpha x 60 / 7 s base reload = 114,000. All upgrades (top gun): 13,300 HE full-salvo alpha x 60 / 6.5 s all-upgrades reload = 122,769.
Shells/minInitial: 60 → 64.6
Zero upgrades: 7 broadside guns x 60 / 7 s base reload = 60. All upgrades (top gun): 7 broadside guns x 60 / 6.5 s all-upgrades reload = 64.6.
Fires/minInitial: 5.4 → 5.82
Zero upgrades: 60 shells/min x 9% fire chance = 5.4. All upgrades (top gun): 64.6 shells/min x 9% fire chance = 5.82.

Torpedoes

Torpedo detectability1.6 km
Estimated torpedo reaction time8.5 s
detectability / (speed kt x 2.6 community game-speed factor).
Torpedo speed72 kt
Travel time to max range40.1 s
range / (speed kt x 2.6 community game-speed factor).
Tube count6
2 launchers x 3 tubes.
Per-side salvo6 torpedoes
6 (centerline launchers train across - full salvo to either side).
Full-salvo damage40,998
All tubes hitting one target: tubes x per-torpedo simulated damage = 6 x 6,833 = 40,998.
Per-side salvo damage40,998
One side firing, all torpedoes hitting: per-side tubes x per-torpedo simulated damage = 6 x 6,833 = 40,998.

AA defense

Close-range AA DPS131
Sum across every AA aura on this ship of (aura.continuous_damage x 3.5 x aura.hit_probability). Here: (25×3.5×1) + (13×3.5×0.95) = 131. Covers AA-only mounts plus dual-purpose secondaries (Bismarck 105mm, USN 5"/38 cruiser secondaries) and dual-purpose main batteries (Sumner-class 5"/38, Akizuki-line 100mm). Formula validated against in-game captures on California, Sumner, Manfred von Richthofen, Dante Alighieri (exact) and within +/-17% on the remaining verified ships. Flak is NOT included: flak stops triggering once planes are inside 2.5 km, and its avoidable burst damage is shown separately in the Flak bursts section.
Maximum AA range3.5 km
Longest-reaching aura across AA-only + dual-purpose auras.
AA threat index358
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 range1.2 km

Armor Beta

Hull HP 12,90015,500 with hull upgrade, distributed across 5 hull zones, each with its own plate thicknesses, saturation cap, and pen thresholds. HP caps are the exact in-game values, not estimated.

Bow & stern16 mm

Overmatched by 124+ guns across the bracket. Can’t reliably bow-tank; gets bow-citadelled and overpenned.

Farming10 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 15–16 mm)2,300 (15% of HP)
Overmatch not possible in its bracketAngle 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 mm primary (range 15–16 mm)11,600 (75% of HP)
Overmatch not possible in its bracketAngle 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 6–16 mm)1,200 (8% of HP)
Overmatch not possible in its bracketAngle bounces 203mm16 mm: HE pens from 127mm+
Mirror of bow. Same fast saturation.
Citadel16 mm primary (range 10–16 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.
Superstructure10 mm primary (range 10–16 mm)1,100 (7% of HP)
Any HE ≥16 mm pens at full damage
Any HE ≥16 mm pens at full damage. HE-spam target, and the section saturates fast (often only a few thousand HP).
Turret (module, per magazine)separate HP pool, does not drain ship HP7,800 magazine HPMagazine detonation1–30% chance · below ~75% HPPer-turret powder-magazine HP. Detonation chance scales from 1% (no mag damage) to 30% (full mag damage); this range is the in-game value. Detonation can't roll while the ship is above ~75% HP (the standard detonation-protection threshold, not a per-ship stat). Smaller magazines saturate to the 30% ceiling faster.
AA mount (40 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.
Rudder (module)separate HP pool, does not drain ship HP4,700 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.

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Exteriors

Skins & permanent camouflages

Every custom exterior Grom can equip, from in-game data.

  • Grom 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.