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# Combat/Overweight Penalty and Fit Gun Bonus

The "hidden fit bonus" mechanic refers to some ships receiving bonuses or penalties when equipping certain equipment, depending on if the equipment "fits" the class or not.

• This almost exclusively refers to main guns, where each class of ship is engineered to carry up to certain gun calibers, and so, equipping gun turrets of the right caliber or lower will imply an accuracy bonus, whereas using larger calibers will result in some overweight penalties.
• Not to be confused with visible Equipment Bonuses.

As hidden bonuses are unaffected by morale or fleet types (e.g. combined fleets), it can be interesting to utilize those fit bonuses as much as possible.

Such fit mechanics do not apply to abyssals.[1]

# Large Caliber Main Guns

Battleships receive accuracy bonuses if the guns are fit and accuracy penalties if its overweight[1]. 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.

Ship Class ()(),
(),
(),
()
,
,
41cm 16inch (United States Navy) 16inch (Royal Navy) 46cm ,
,
,
+7
30.5cm: +10
0 +1 -7 -3 -9~10? ?? ?? -7 -18 ?? N/A
+7 0 -2 -5 -5? -5 -6~7? -5 -6 -3 -7 -10 -10?

+4 0? +1 -5 -5 -4? -5 ?? ?? -7 -10 ??
+4? 0? -2? -5 0 +2 -7 -10 ??
-5
M: +4.6
+4 +4~5 -2 -5 -5 -7 -14? -8 -7 -10 ??
+6
38.1cm: +8
+1~2 +2 -2? +5 ?? +3~4 -8 -11 ??
0 0 +3? 0 0
+4 0 +2 +2 0 0? -3 -7
F+: -11?
-4?
+4? 0? +4? +4? +6 +2 ?? -7
F+: -11?
??
+2 0? +2 +2 +2 +2? +3 -3 -7 ??
0 ??
+2? 0? +2? +5 +5 +5~6 0 +4 -2? -4? -6? Nagato: -5
Mutsu: -8
??
0 +3 +3 +7 0 ??
[2] (FBB) 0 ?? -7 ?? ?? -10
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 mean that it is 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 arise where different guns of the same class give different bonuses on certain ships, notably Gangut. What would happen if you combine 30.5cm and 35.6cm is still under investigation.
• The information in this table is sourced from this spreadsheet maintained by Dewy with the relevant sources linked in the spreadsheet.
Last Updated: Aug 24th 2020 Made by: Tsubakura

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

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

Where:

• $\displaystyle{ W }$ is the resulting fit bonus or overweight penalty
• $\displaystyle{ C_{k} }$ 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.
• $\displaystyle{ M_{k} }$ 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.
• $\displaystyle{ N_{k} }$ is the number of equipped guns for that gun class.

### Native Guns

Since gun overweight penalty and fit bonuses are not yet all measured for some guns and ships, here is a list of the guns natively used/planed to be used in real life by each ship class.

• The "Twin/Triple" mount distinction is made for convenience, triple guns being heavier than their twin counterpart.
• Equipping ships with those guns may not always be optimal, but this should avoid most overweight penalties.
Large Guns
Nation Class Caliber Twin Triple
Japanese Kongou-class
Fusou-class
Ise-class
35.6 cm
35.6cm Twin Gun Mount
35.6cm Twin Gun Mount (Dazzle Camouflage)
35.6cm Twin Gun Mount Kai
35.6cm Twin Gun Mount Kai Ni
Prototype 35.6cm Triple Gun Mount
35.6cm Triple Gun Mount Kai (Dazzle Camouflage)
Fusou-class Kai Ni
Ise-class Kai Ni
Nagato-class
41 cm
41cm Twin Gun Mount
41cm Twin Gun Mount Kai Ni
Prototype 41cm Triple Gun Mount
41cm Triple Gun Mount Kai
41cm Triple Gun Mount Kai Ni
Yamato-class 46 cm
Prototype 46cm Twin Gun Mount
46cm Triple Gun Mount
46cm Triple Gun Mount Kai
Yamato-class Kai Ni 51 cm
Prototype 51cm Twin Gun Mount
51cm Twin Gun Mount
Prototype 51cm Triple Gun Mount
16inch Mk.I Twin Gun Mount
16inch Mk.V Twin Gun Mount
16inch Mk.VIII Twin Gun Mount Kai
North Carolina-class
South Dakota-class
16inch Triple Gun Mount Mk.6
16inch Triple Gun Mount Mk.6 + GFCS
16inch Triple Gun Mount Mk.6 mod.2
Iowa-class
16inch Triple Gun Mount Mk.7
16inch Triple Gun Mount Mk.7 + GFCS
British Queen Elizabeth-class 38.1 cm
38.1cm Mk.I Twin Gun Mount
38.1cm Mk.I/N Twin Gun Mount Kai
Nelson-class 40,64 cm
16inch Mk.I Triple Gun Mount
16inch Mk.I Triple Gun Mount + AFCT Kai
16inch Mk.I Triple Gun Mount Kai + FCR Type 284
Italian Conte di Cavour-class 30.5 cm
305mm/46 Twin Gun Mount
305mm/46 Triple Gun Mount
32 cm
320mm/44 Twin Gun Mount
320mm/44 Triple Gun Mount
Vittorio Veneto-class 38.1 cm
381mm/50 Triple Gun Mount
381mm/50 Triple Gun Mount Kai
German Bismarck-class 38 cm
38cm Twin Gun Mount
38cm Twin Gun Mount Kai
French Richelieu-class 38 cm
38cm Quadruple Gun Mount Kai Deux

'"Double Twin Guns" in a Quadruple Mount.
Russian Gangut-class 30.5 cm
30.5cm Triple Gun Mount
30.5cm Triple Gun Mount Kai

# Medium Caliber Main Guns

Cruisers can receive accuracy and/or firepower bonuses from using fit guns in their load-out.

Ship Class
()

Day Night
CL(T) +4N +1 ?? +2? +2 +3 ?? -2 -2N -3N?[1] -2 -2.5N? -10N?
?? +5 +2N? +2 -2 -2N
?? +2? +2 +2
CA(V) 0 +5 +5N? 0
+2
+5
+1 +1
Seaplane Tenders (AV) -6N -6N -8 -10N -8 -10N?

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 mean that it is potentially outdated and might no longer be correct.

• The table shows an estimated accuracy and/or firepower fit bonus based on having one fit gun equipped.
• The variable N refers to the number of guns of that category equipped. (Ex: 2 guns of 2N = 4 ACC)
• Bonuses from guns of different classes are simply added together.
• The night fit bonus from the 20.3cm series used to be capped at +15%. However, it is unknown whether this cap has been removed or not from the recent updates.
• There is a possibility that certain fit categories only work during the day. The possibility is plausible, but there's no concrete data proving. The alternative theory is that the night bonus from the 20.3cm series overrides any other categories.
• The information in this table is sourced from these two spreadsheets (1) (2) the latter maintained by Dewy, both with the relevant sources linked in the spreadsheet.
• As of 13th December 2018 the hidden firepower bonus of does not work/does not exist[citation needed].
Last Updated: June 23rd 2019 Made by: Tsubakura

# Small Caliber Main Guns

As of 2017/06/23, Yura and Mutsuki/Kamikaze-classes of destroyers gain bonuses with some main HA guns .

Ship
Light Cruisers (CL) +4N +2 +2N
+4 +10N
+5
??

Unknown factors:

• Only and were tested[citation needed]. It's unknown whether the other ships in the same class would receive the same bonus or whether it only works for specific remodels.
• The variable N refers to the number of guns of that category equipped (ex: 2 guns of 2N = 4 ACC).
• It is unknown whether the gives a fit bonus or not.
• The information in this table is sourced from this spreadsheet maintained by Dewy, but has no sources linked in the spreadsheet.
Last Updated: December 5th 2018 Made by: Tsubakura

# DD Fit Accuracy

Certain DDs have a higher-than-expected hit rate when equipped with certain guns or sonars.

• The bonus accuracy likely takes the form: $\displaystyle{ \text{ACCURACY}_\text{bonus} = \text{C} \times \sqrt{\text{N}} }$
• N being the amount of equipment.
Known "C" values
Ship/Class Gear C
5
4[1]
4[2]
3
3 [3]
5
Source: [1][2]
1. 2x on Fletcher-class gives ~10 accuracy. This is potentially a bug.
2. Samuel B.Roberts does not seem to receive any bonus from . This is possibly a bug (maybe related to the bug on Fletcher-class).
3. There are not enough samples on more than one sonar so it is not clear how does the accuracy bonus scales. This bonus can stack with the accuracy bonus from .