Artillery Spotting

'THIS PAGE IS UNDER CONSTRUCTION. THEREFORE, CONTENT BELOW ARE SUBJECT TO CHANGE.'

- Recent Update:
 * Dec 19, 2014 by homuhomu123
 * Translation added for the Japanese source data (艦これ-チラ裏検証), from which fundamental assumptions were made
 * Notice added for section introduction.
 * Dec 15, 2014 by homuhomu123
 * Section "Effectiveness of Artillery Spotting" added. Special thanks for Nainodel's article "All About Firepower"
 * Dec 12, 2014 by homuhomu123
 * CI chance modifier for AA radars evaluated to be 24%, in contrast to surface radar's 30%.
 * Dec 12, 2014 by homuhomu123
 * CI chance modifier for AA radars evaluated to be 24%, in contrast to surface radar's 30%.

Introduction:
This page studies the trigger rates & effectiveness of Artillery Spotting, based on credible in-game testing. An optimal use of Artillery Spotting could considerably improve your fleet's daytime combat performances.

''Please be aware on the part of Artillery Spotting trigger rate estimate. They are not 100% accurate, or even close to the actual codes written. However, the more battles you proceed, you should find those estimates being very close to the actual ones. The estimate formula are constantly being revised, not yet mature (error ~5%), thus more experiments are being conducted for refinement.''

In brief, Artillery Spotting consists of two types of attack: Cut-In [CI] & Double Attack [DA]. When activated, the attacking ship receives a damage output (post-cap) & accuracy bonus. More detailed explanations could be found on the page Game Mechanics -> Artillery Spotting.

Double Attack

 * 2 x Main + 1 Seaplane........................................(basic setup)
 * 2 x Main + 1 Seaplane + 1 Seaplane
 * 2 x Main + 1 Seaplane + 1 Radar........................(highest DA chance)

''>> DA Damage: 120% (post cap) x 2. More powerful for ships with high shelling accuracy and against lighter armor units.''

Cut-In
''>> CI Damage: 110% / 120% / 130%. Works well for ships with high firepower while giving more chances for Artillery Spotting.''
 * 1 x Main + 1 x Sec + 1 Seaplane...................................(basic setup)
 * 1 x Main + 1 x Sec + 1 Seaplane + Radar......................(highest CI chance)
 * 1 x Main + 1 x Sec + 1 Seaplane + AP Shell

>> Set up #2 triggers either secondary gun CI (110%) or radar CI (120%).

Hybrid (DA+CI)
''>> CI Damage: 130% / 150%. More CI expected than DA. Giving the highest base rate for triggering Artillery Spotting.''
 * 2 x Main + 1 x Sec + 1 Seaplane
 * 2 x Main + AP Shell + 1 Seaplane

The Trigger Chance of Artillery Spotting: (Beta ver.)
Possible factors are listed below, followed by their estimated effects. These values / formula might be far from the actual ones, but they do give good estimates for the activation rates

The first 5 factors are derived from 艦これ-チラ裏検証- (click here for a translated version) and will be verified in future experiments. In addition, these hypothesis will be used as fundamental assumptions in experiment data analysis.: The following factors have negligible effects on the trigger rates: The following factors might have an effect on the trigger rates:
 * 1)  Being the flagship / 旗艦  (+15% for both rates)
 * 2)  Radar & type / 電探  (+30% CI chance, +13% DA chance, maximum)
 * 3)  Air Supremacy or Superiority / 制空権の状態  (-12% for both if only Air Superiority is achieved)
 * 4)  Fleet total LoS / 艦隊合計索敵値/  (+8% DA rate, +10% CI rate, per 100 additional LoS)
 * 5) LoS Values on Seaplane /  水上機の索敵補正値  (minimal effects)
 * 1) Fatigue / 疲労度  (No effects after Xmas update ?? Severe fatigue penalty was estimated to be -12% on DA chance)
 * 2) Health state / HP (Less than 5% penalty on DA chance ?? )
 * 3) Level / レベル (Negligible effects ?? Assumption based on test results here)
 * 4) Formation / 陣形

Detailed Explanation:
1. Before we start, let's assume a standard situation, in which Fleet total LoS = 300, test ships are beyond minor damage(小破未満) and morale condition = 49. Fleet formation Line Ahead, and Air Supremacy (AS+) is achieved for every battle. Based on test results from 艦これ-チラ裏検証 (click here for a translated version), we may come up with following hypothesis:

- BB(V) equipped with 2 x Main & 1 seaplane has DA rate ~ 50%.

- CA(V) quipped with 2 x Main & 1 seaplane has DA rate ~50% ??

- BB(V) equipped with 1 x Main + 1 x Secondary & 1 seaplane has CI rate ~ 50%

- CA(V) equipped with 1 x Main + 1 x Secondary & 1 seaplane has CI rate ~50% ??

- It was suspected that CLs & some CAs have 5% lower DA/CI base rate ??

2. As total fleet LoS incremented from 300 -> 400, the trigger rates increase slightly:

- DA rate + 8%, per 100 additional LoS, approximately.

- CI rate + 10%, per 100 additional LoS, approximately.

- Relation supposed to be linear for any LoS level ??

3. If an additional seaplane scout is added onto the 4th slot:

- DA rate +5% ??

- CI rate +0% ??

- Actual effects are to be further determined.

4. If we replace the extra seaplane with a radar, and compare the results to those from the standard situation:

- DA rate rises by 4 % ~ 13 % approximately, depending on the accuracy stat of the radar ??

- CI rate rises by 30% (surface radar) or 24% (AA radar), approximately ??

- List of radars with their Estimated DA/CI rate modifier (Require further verification)
5. Different seaplane scouts vary slightly in the DA trigger rate bonus:

- Type 0 Observation Plane & Prototype Seiran (+ 6 LoS) give the highest bonus. (+1%) ??

- Night Scout (+ 3 LoS) gives less bonus on DA chance (-2%) ??

- DA chance bonus depends on both stats ??

- Different seaplanes have no effect on CI chance ??

- This part is currently negligible in DA/CI rate estimate calculation.

- List of seaplanes with their Estimated DA rate modifier (Extremely rough estimates, NOT used in calculation)
6. For standard BB(V)s, aka non-Yamato class BBs, radars could be replaced by AP Shells for a cut-in setup (Main / Secondary / AP / seaplane), which gives a 20% trigger chance bonus on CI. However, you could also use AP shells (or Secondary) for a hybrid set up  (2 Main / AP (or Secondary) / seaplane). In the standard situation, the combined Artillery Spotting chance is about 70%.

- AP shell hybrid setup (with 41cm x 2): CI = ~38% & DA = ~32%. ??

- AP shell hybrid setup (with 46cm x 2): CI = ~43% & DA = ~27%. ??

- Secondary gun hybrid setup:              CI = ~50% & DA = ~20%. ??

- For hybrid setup, every 100 additional LoS will only increase CI chances by 5%.  ??

- Replacing Type 0 Recon by  Type 0 Observation Seaplane  will increase DA rate by 3%. ??

- These estimates are based on very limited test results, thus lower credibility.

- Brief Conclusion: Huge caliber guns and/or secondary gun on standard BB(V) would trade some DA for more CI chances.

7. If Air Superiority [AS] rather than Air Supremacy [AS+], then both rates fall significantly:

- Both CI & DA chance falls by at least 12%

- In the case of a hybrid setup, CI chance falls by 11% while DA rate -7%. ??

- If you're using the hybrid setup, it's more recommended to achieve Air Supremacy (AS+) for your fleet.

8. The flagship has a significantly higher chance (+15%) of triggering Artillery Spotting

- In the case of a hybrid setup, CI chance +7.5% while DA rate +7.5%.



Image source: 艦これ-チラ裏検証- .

Explanation: Blue = DA, Yellow = CI, Brown = Single attacks.
 * 1) TOP LEFT: Trigger rates for flagship (outer) & companion ship (inner) with hybrid setup
 * 2) TOP RIGHT: The plotting of artillery spotting rate versus fleet total LoS (flagship status &/or equipment bonus NOT excluded) 
 * 3) BOTTOM LEFT: Flagship & her companion ships with DA basic setup.
 * 4) BOTTOM RIGHT: Flagship & her companion ships with CI basic setup. 

Artillery Spotting Trigger Rate Estimate: (Beta ver.)
NOTE: As mentioned before, these calculation only serves as rough estimates on your ship's artillery spotting chances. More credible tests (Sample size > 170) are required to come up with a better formula. Deviations from actual test results are supposed to be less than 5%, otherwise reworking on the formula itself should be considered. This does not include effects from fatigue, HP status(中破), and undetermined factors like formation, level differences (>>10), a few special ships or maps, etc.

Sample Calculation for DA:
1) Fuso, AS+, having Fleet LoS = 300, equipped with 2 main, #32 radar & Type 0 Observation will have a: 2)  Prinz Eugen, AS+, Fleet LoS = 300, equipped with 2 main, FuMO32 & Ar196 will have a: 3)  Chikuma, AS+, Fleet LoS = 400, equipped with 2 main, #22 radar & Type 0 Recon will have a: 4)  Haruna, {flagship}, AS+, Fleet LoS = 300, equipped with 2 main, #22 radar & Type 0 Recon will have a: 5)  Mutsu, {flagship}, AS, Fleet LoS = 300, equipped with 2 main guns, #22 radar & Type 0 Recon will have a:
 * DA chance of ...
 * 50%( BB Base) + 13%[Radar Modifier] + 0%(LoS Modifier) +1%  = 63%
 * DA chance of ...
 * 50%( CA Base)+ 16%[Radar Modifier]+ 0%(LoS Modifier) +0%  = 66%
 * DA chance of ...
 * 50%( CA Base)+ 4%[Radar Modifier]+ 8%(LoS Modifier) +  0% = 62%
 * DA chance of ...
 * 50%( BB Base)+ 15%{Flagship Modifier} + 4%[Radar Modifier]+ 0%(LoS Modifier)= 69%
 * DA chance of ...
 * 50%( BB Base)+ 15%{Flagship Modifier} - 12%(Air Superiority) + 4%[Radar Modifier]+ 0%(LoS Modifier)= 57%

Sample Calculation for CI:
1) Fuso, AS+, Fleet LoS = 300, equipped with 1 main + 1 sec, #22 Surface radar & seaplane will have a: 2)  Atago, AS+, Fleet LoS = 300, equipped with 1 main + 1 sec, #14 AA radar & seaplane will have a: 3)  Mutsu, AS+, Fleet LoS = 400, equipped with 1 main + sec, AP shell & seaplane will have a: 4)  Kumano, AS+, Fleet LoS = 400, equipped with 1 main + 1sec, #32 Surface radar & seaplane will have a:
 * CI chance of ...
 * 50%( BB Base)+ 30%[Radar Modifier]+ 0%(LoS Modifier) = 80%
 * CI chance of ...
 * 50%( CA Base)+ 24%[AA Radar Modifier]+ 0%(LoS Modifier) = 74%
 * CI chance of ...
 * 50%( BB Base)+ 20%[AP Shell Modifier]+ 10%(LoS Modifier) = 80%
 * CI chance of ...
 * 50%( CA Base)+ 30%[Radar Modifier]+ 10%(LoS Modifier)= 90%

Sample Calculation for Hybrid Setup: (lower credibility suspected ??)
1) Mutsu, AS+, Fleet LoS = 400, Type 0 Recon, AP shell setup with 41cm x 2:
 * Total artillery spotting rate = 70%(BASE) + 5%(LoS Modifier for CI) = 75%.

2) Kongou, AS+, Fleet LoS = 400, Type 0 Observation Seaplane, AP shell setup with 46cm x 2:
 * CI% = 38%(AP BASE) + 5%(LoS Modifier) = 43%
 * DA% = 32%(AP BASE) = 32%
 * Total artillery spotting rate = 70%(BASE)+ 5%(LoS Modifier for CI) + 3%(Obsv.Seaplane) = 78%
 * CI% = 43%(AP BASE, Overload) + 5%(LoS) = 48%
 * DA% = 27%(AP BASE, Overload) + 3%(Obsv.Seaplane) = 30%

Effectiveness of Artillery Spotting
Some of the suggestions are derived from article All About Firepower by Nainodel.

DA:
- For BB(V), an appropriate caliber gun set up (eg. 35.6cm x2 for Fuso) will increase their DA accuracy. Penalty on overload setup (eg. 46cm x2 on FBB) has not been tested.

- It gives accuracy boost.

- More dependent on shelling accuracy if you wish to maximize your damage output (120% post cap x 2)

- If T-disadvantage and/or low firepower, DA would probably do a double-scratch on enemy with heavy armor.

- Recommended for enemy with lower armor than or equivalent to Ru-Class Battleships.

- If either attack could wreck the enemy (eg. low armor w/ high evasion), preferably DA due to higher chance of hitting the target..

CI:
- Since AP shell works well on heavy armor enemies, and is only available for CI setup, CI is recommended when dealing with Ru-Class Battleships and above.

- Highest damage (from a single attack): 130% post cap, for AP shell CI setup, or 150% post cap, for AP shell hybrid setup.

- It gives accuracy boost. (If not equivalent to that from DA ??)

- Accuracy plays an important role in CI, since you have only 1 chance to hit the enemy (2 for DA).

- For an AP hybrid setup, overload (eg. 46cm x2 on Nagato Class) may shift some DA chances into CI. Therefore, for BBs with low firepower, you may consider using an overload setup for more firepower & CI when encountering high armor, low evasion enemies. (Hypothesis Only)

- Since AP shells are not accessible to CA(V), their maximum CI damage is 120% post cap with radar. However, if secondary-gun hybrid is used on CA, it could be 130%, but reliability has not been tested.

- Read more: Comparative study on DA/CI with sample enemies.

Uncertainty

 * It seems that there should be a CI trigger-rate-cap above 90%. It doesn't make sense to have a CI chance more than 100%, for a set up like BB (50%) + radar [30%] + flagship{15%} + LoS modifier (10%) = 105%.
 * Test results from CA are more volatile. It seems that for some CAs, LoS doesn't really affect their CI/DA chances ??