This article is Overweight Penalty/Fit Gun Bonus
The article is already being adopted and currently under renovation.
Missing Information: Fit Gun table for BB, updated information and sources, quantified effects
Page Adopted By: Tsubakura
Please contact this person before making any major (non-grammar, typo correction, redesigning etc.) edits on this article.

See also: Fit gun bonus - Reddit intermediate players' guide

Fit Bonus and Overweight PenaltyEdit

With the introduction of fit gun mechanics on July 28th 2014, ships now will receive fit bonus/penalties depending if the equipped gun fits for the class or if the gun is too heavy for the ship to use.

As fit bonuses are unaffected by morale or combined fleets, it becomes important that you utilize the fit bonuses as much as possible.

Fit mechanics do not apply to the abyssal fleet.[1]


Battleships receives accuracy bonuses if the guns are fit and accuracy penalties if its overweight.[2] How much bonus/penalty a ship receives, depends on the battleship class, the caliber and type of the gun and whether the battle takes place during day or night.

Note: The gun classification is only there as a reference for editors and does not reflect the terminologies used in-game.

Gun Class Class A Class F Class B Class C Class Y Class D Class E Class Z
Ship Class 30.5cm
30.5cm Triple Gun Mount 231 Card

30.5cm Triple Gun Mount Kai 232 Card
35.6cm Twin Gun Mount 007 Card

Prototype 35.6cm Triple Gun Mount 103 Card

35.6cm Twin Gun Mount (Dazzle Camouflage) 104 Card

38cm Twin Gun Mount Kai 114 Card

38.1cm Mk.I Twin Gun Mount 190 Card

38.1cm Mk.I N Twin Gun Mount Kai 192 Card
38cm Quadruple Gun Mount 245 Card

38cm Quadruple Gun Mount Kai 246 Card
381mm 50 Triple Gun Mount 133 Card

381mm 50 Triple Gun Mount Kai 137 Card
41cm Twin Gun Mount 008 Card

Prototype 41cm Triple Gun Mount 105 Card

41cm Triple Gun Mount Kai 236 Card
16inch Triple Gun Mount Mk.7 161 Card

16inch Triple Gun Mount Mk.7 + GFCS 183 Card
Prototype 46cm Twin Gun Mount 117 Card
46cm Triple Gun Mount 009 Card
Prototype 51cm Twin Gun Mount 128 Card
Day Night Day Night Day Night Day Night Day Night Day Night Day Night Day Night Day Night
Kongou Class
FBB Kongou 078 Battle
FBB Hiei 086 Battle
FBB Kirishima 085 Battle
FBB Haruna 079 Battle
+7 -2 -2 0 -5 -5 -7 -10 N/A
Bismarck Class
FBB Bismarck 171 Battle
+4 ?? +3 0 -5 -2? -2? -10 N/A
Гангут Class
FBB Gangut 511 Battle
+10 +7 ?? +1 0 -7 -7 -10 -16 N/A
Richelieu Class
FBB Richelieu 492 Battle
+4 +4 -2 0 -7 -7 -7 -10 N/A
Vittorio Veneto Class
FBB Littorio 441 Battle
FBB Roma 442 Battle
+4 ?? +1 0 -7 -5 -7 -10 N/A
Iowa Class
FBB Iowa 440 Battle
+4 ?? -2 0 -5 +4 -7 -10 N/A
Queen Elizabeth Class
BB Warspite 439 Battle
+4 ?? +2 0 +2 0 -3 -10 N/A
Ise Class (Base)
BB Ise 077 Battle
BB Hyuuga 087 Battle
+2 ?? +2 0 +2 +2 -3 -7 N/A
Fusou Class (Base)
BB Fusou 026 Battle
BB Yamashiro 027 Battle
+2 ?? +2 0 +2 +2 -3 -7 N/A
Ise Class (Kai)
BB Ise 077 Battle
BB Hyuuga 087 Battle
+4 ?? +2 0 +2 0 -3 -5 -7 -8 N/A
Fusou Class (Kai/Kai Ni)
BBV Fusou Kai 286 Battle
BBV Fusou Kai Ni 411 Battle
BBV Yamashiro Kai 287 Battle
BBV Yamashiro Kai Ni 412 Battle
+4 ?? +2 0 +2 0 -3 -5 -7 -8 N/A
Nagato Class (Base/Kai)
BB Nagato 080 Battle
BB Mutsu 081 Battle
+2 ?? +2 0 +2 +2 -3 -7 0
Nagato Class (Kai Ni)
BB Nagato Kai Ni 541 Battle
?? ?? ?? 0 +5 0 -3 -5 0
Yamato Class
BB Yamato 131 Battle
BB Musashi 143 Battle
0 0 0 0 0 0 0 0

Note: Fit gun mechanics are still being investigated to this day, hence the values are not final and may be subject to changes. Values with a question mark either means that its not conclusive yet or the conclusion drawn here is not the same as the one drawn by yumeji.

  • The table shows an estimated accuracy fit bonus based on having one fit gun equipped.
  • For married ships, the overweight penalty is reduced by 40% (A married Kongou with a 46cm receives a penalty of -6 instead of -10, for example).
  • If more than one gun of the same class is used, multiply the modifier by the square root of number of guns. (A Kongou-class with two A class guns equipped for example, that's √2 x 7 = 9.89)
  • If guns from different classes are used together, add the modifiers together. (A Kongou with a 35.6cm and 41cm mixed for example, that's 7 - 5 = 2.
  • Exceptions arises where different guns of the same class gives different bonuses on certain ships, notably Gangut. What would happen if you combine 30.5cm and 35.6cm is still under investigations.
Last Updated: October 13th 2017 Made by: Tsubakura

More generally, the accuracy offset can be defined with the formula:

W = \sum^{\text{All Classes}} \left ( C_{k} M_{k} \sqrt{N_{k}} \right ) \%


  • W is the resulting fit bonus or overweight penalty
  • C_{k} is the main coefficient of the equipped gun class. Refer to the above table for the coefficients applied to each Battleship for their respective guns.
  • M_{k} is the marriage coefficient for the particular gun class. Assumes a value of 0.6 if the ship is married, and if the main coefficient is negative.
  • N_{k} is the number of equipped guns for that gun class.

Heavy CruisersEdit

Heavy/Aviation cruisers only require one fit gun to get their fit bonus, there are no overweight mechanics regarding cruisers. Keep in mind that the fit bonus only applies during a night battle and equipping more than one of the same fit gun will not give you any duplicate bonuses. The fit bonuses also apply to torpedo attacks, as there are no distinction between shelling or torpedo based night attacks.
The following guns will give you a fit bonus:

Note: It is currently unknown what would happen if you combine different fit guns.

The following guns are confirmed not to give any fit bonuses:

Light CruisersEdit

Light Cruisers, Torpedo Cruisers and Training Cruisers all enjoy an accuracy and firepower bonus when equipped with fit guns. Like Heavy Cruisers, Light Cruisers do not have overweight mechanics.[3]


Light Cruisers, Training Cruisers, and Torpedo Cruisers enjoy firepower increase when using any of the following gun:[4]

It have been suggested that the increase in firepower might follow this relationship:[4]

  • Increase in Firepower = √(No. of Fit Single Gun Mount) + 2 × √(No. of Fit Twin Gun Mount)


So far, only limited amount of tests have been conducted to study light cruiser fit gun's effect on accuracy so all information in this section are in-comprehensive and they might be superseded by other, more up-to-date investigations when those information are available.

The accuracy fit bonus only applies if 2 or more fit guns are equipped at the same time. Equipping more than 2 fit guns does not increase the fit bonus.[5] Accuracy increase have been observed for the following guns when they are being equipped on CL[4]

Accuracy increase have been observed for the following guns when they are being equipped on CLT[6]

Accuracy increase have been observed for the following guns when they are being equipped on CT[7]

Other combinations have not been fully tested yet.

The possibility of accuracy bonus vary across different ship classes have not been ruled out yet.[6]

Third party Inspection on BB Fit GunEdit

Third part Inspection on CA(V) Fit GunEdit

Third party Inspection on CL Fit GunEdit


  4. 4.0 4.1 4.2 巡洋艦主砲【フィット補正】
  6. 6.0 6.1 軽巡フィット命中検証