Ship armor test

[sekelsenmat]

In a different thread someone doubted that ship armor does anything if armor < piercing, so I devised a test:

* ai off, ic mode on
* Changed ship armors BB1, BB2, BC1, BC2 to all have no speed penalty, all provide 10x HP increase(so the test can be very long, reduce RNG), removed all visibility differences between armors, etc
* Changed BB gun 2 to give zero damage, so that the UK would never receive any damage

* Italy, created 4 battleships with only Gun2 (zero damage) and each a different armor scheme:
--> Armor 2800
--> Armor 36
--> Armor 20
--> Armor 0
* UK created 3 BB1 Queen Elizabeth or something like that, it has BB-gun-1 (Piecing 31) & some secondary.

Put them to fight.

Results:

R1> Armor 20 and Armor 0 received exactly the same Heavy Gun damage (about 800). Later I tested with armor 27 and same result.
R2> Armor 36 received about 70% of the damage in R1 (about 565)
R3> Armor 2800 received damage aprox 70
R4> Armor 0 received significantly more damage from Light Gun than Armor 20 (150 vs 40 aprox)

Conclusion:

C1> The armor is useless if it is smaller than the piercing, which means that I was wrong.
C2> Despite that, smaller amounts of armor are not totally useless, because Armor >> Piercing significantly decreases damage, so lower tier armors protect vs Destroyer guns and Cruiser guns
C3> Possible formula for the damage multiplier could be:
* 1, or no change, if Armor < Piercing
* Some formula (not enough data to say which one), but could be 1 - (0.1 + 2 * 0.9 * (Armor - Piercing) / Armor), min 0.1, max 0.9, if Armor > Piercing

I tried other armor values but RNG doesn't allow me enough precision to get to the formula.

 

[Black_Shade]

Interesting test.

So I guess this means that the strategy of having destroyers loaded with torps for screens and then a cruiser build with max LA and only one heavy battery (to classify it as a capital) and no armor is the way to go for fleets? The destroyers kill the capitals while the cruisers kill the screens, and both are maxed out for speed.

 

[HugsAndSnuggles]

Yeah, look like not bothering with armour is a safer bet: you can never be sure it won't get penned.

 

[desphorin]

Interesting test.

So I guess this means that the strategy of having destroyers loaded with torps for screens and then a cruiser build with max LA and only one heavy battery (to classify it as a capital) and no armor is the way to go for fleets? The destroyers kill the capitals while the cruisers kill the screens, and both are maxed out for speed.

Fairly certain this is the meta for quite a while already.

 

[ecpgieicg]

In a different thread someone doubted that ship armor does anything if armor < piercing, so I devised a test:

* ai off, ic mode on
* Changed ship armors BB1, BB2, BC1, BC2 to all have no speed penalty, all provide 10x HP increase(so the test can be very long, reduce RNG), removed all visibility differences between armors, etc
* Changed BB gun 2 to give zero damage, so that the UK would never receive any damage

* Italy, created 4 battleships with only Gun2 (zero damage) and each a different armor scheme:
--> Armor 2800
--> Armor 36
--> Armor 20
--> Armor 0
* UK created 3 BB1 Queen Elizabeth or something like that, it has BB-gun-1 (Piecing 31) & some secondary.

Put them to fight.

View attachment 597667View attachment 597666

Results:

R1> Armor 20 and Armor 0 received exactly the same Heavy Gun damage (about 800). Later I tested with armor 27 and same result.
R2> Armor 36 received about 70% of the damage in R1 (about 565)
R3> Armor 2800 received damage aprox 70
R4> Armor 0 received significantly more damage from Light Gun than Armor 20 (150 vs 40 aprox)

Conclusion:

C1> The armor is useless if it is smaller than the piercing, which means that I was wrong.
C2> Despite that, smaller amounts of armor are not totally useless, because Armor >> Piercing significantly decreases damage, so lower tier armors protect vs Destroyer guns and Cruiser guns
C3> Possible formula for the damage multiplier could be:
* 1, or no change, if Armor < Piercing
* Some formula (not enough data to say which one), but could be 1 - (0.1 + 2 * 0.9 * (Armor - Piercing) / Armor), min 0.1, max 0.9, if Armor > Piercing

I tried other armor values but RNG doesn't allow me enough precision to get to the formula.

Great experiment. Very nice!

Are you able to try 30 armor against 31 piercing?

This line

COMBAT_ARMOR_PIERCING_DAMAGE_REDUCTION = -0.9,                    -- All damage reduction % when target armor is >= then shooter armor piercing.

from defines seems to either suggest an all or nothing change or the max reduction is attained right when armor is at parity as piercing, which in turn seems to suggest some damage reduction shortly below parity. Hence I wonder if 30 armor would make a difference.

Also consequential is whether light piercing follows the same rule as heavy piercing. If light gun damage is more significant at low armor, it makes medium armor a bit more useful.

 

[Kommandant bubba]

If armor is so effective if you cannot get pierced, why wouldn't you use light cl with the best armor availible and load it with light attack and torps? It would seem to be better because then the heavy attack would be focused on your capitals which can tank hits, while your light cl's are used to screen while taking less damage due to light attack not being able to pierce their armor. But a heavy cl would get decimated by hard attack quickly and not do much good. I know destroyers can have very high speeds making them harder to hit with heavy attack, but they have no health or armor which doesn't seem to make them work well as screens. Is there something I am missing?

 

[ecpgieicg]

If armor is so effective if you cannot get pierced, why wouldn't you use light cl with the best armor availible and load it with light attack and torps?

I would. That's always how I build CL. Armor is always maxed. And that's why CAs are useful despite of not being able to screen BBs -- 'properly' built CLs can't pen each other.

I know destroyers can have very high speeds making them harder to hit with heavy attack, but they have no health or armor which doesn't seem to make them work well as screens. Is there something I am missing?

In my games using Black ICE, AI DDs tend get one shot by my BBs/BCs. But very good DD costs 2k ish IC while good CL costs almost 10k. The mod restricts max dockyard per line to 3 regardless of ship type. Plus some additional modules that add % changes to IC. So production matters a bit more. But the same idea still applies to vanilla HOI4.

 

[Morbus Bubbonicus]

Binarry options are cancer. Piercing in both amor and navy is ruining the mechanics

 

[Adolf - Finite War]

Binarry options are cancer. Piercing in both amor and navy is ruining the mechanics

True - Tanks have less armoured places on the side, back and top which doesn't matter much in the open planes of western Russia were battle takes place at distance of up to 2km but in cities or wooded areas where Infantry can get close and utilize close range AT weapons like the Bazooka and the Panzerschreck and Tanks can more easily flank and ambush each other.

As for ships SHBS have extreme armour values are available early on and never become outdated since you can update the engines - takes a year though. The only downside is getting them in numbers and that their reliability score is inferior to more modern regular BS as in real life though they still die rather easily when Airpower is involved even if they are filled to the brim with AA.

 

[Mister Analyst]

If armor is so effective if you cannot get pierced, why wouldn't you use light cl with the best armor availible and load it with light attack and torps? It would seem to be better because then the heavy attack would be focused on your capitals which can tank hits, while your light cl's are used to screen while taking less damage due to light attack not being able to pierce their armor. But a heavy cl would get decimated by hard attack quickly and not do much good. I know destroyers can have very high speeds making them harder to hit with heavy attack, but they have no health or armor which doesn't seem to make them work well as screens. Is there something I am missing?

@Kommandant bubba ,

Welcome to the HOI4 forum! Great question and first post.

You might try exploring the HOI4 wiki. It is a great resource for understanding the game better. Perhaps the section on Naval battle will answer your question.

 

[sekelsenmat]

Are you able to try 30 armor against 31 piercing?

30 armor vs 31 piercing is pierced, so total damage, like armor zero.

I did try to test 30 vs 31 and 32 vs 31, but RNG is so big that I couldn't get any meaningful data for such close calls.

This line

COMBAT_ARMOR_PIERCING_DAMAGE_REDUCTION = -0.9,                    -- All damage reduction % when target armor is >= then shooter armor piercing.

from defines seems to either suggest an all or nothing change or the max reduction is attained right when armor is at parity as piercing, which in turn seems to suggest some damage reduction shortly below parity. Hence I wonder if 30 armor would make a difference.

Also consequential is whether light piercing follows the same rule as heavy piercing. If light gun damage is more significant at low armor, it makes medium armor a bit more useful.

The reduction is not abrupt. You get zero damage reduction while piercing > armor, but once armor > piercing you don't get 90% reduction. 90% is the maximum reduction when armor is much, much greater than piercing (don't know by how much exactly).

Also, light piercing follows the same rule, which is why Battleships receive very little Light Attack damage.

 

[bitmode]

C3> Possible formula for the damage multiplier could be:
* 1, or no change, if Armor < Piercing
* Some formula (not enough data to say which one), but could be 1 - (0.1 + 2 * 0.9 * (Armor - Piercing) / Armor), min 0.1, max 0.9, if Armor > Piercing

If piercing is lower than armor, the formula is (100% - <weapon's armor piercing> / <enemy's armor>) * -90%. As the damage reduction is zero at equal piercing/armor, it can't go any lower when piercing exceeds armor. This is why piercing > armor increases the chance of critical hits instead (albeit not in a scaling manner).

 

[HugsAndSnuggles]

Is there something I am missing?

Production and research costs? Having up to 25% larger firepower (due to numbers) or extra doctrine (freed up research) might, actually, be better than slight decrease in received damage. Also, armour/engine refits are pretty expensive, so as the time goes on, armoured cruisers become worse off, because, once pierceable, it only serves to slow them down.

I did try to test 30 vs 31 and 32 vs 31, but RNG is so big that I couldn't get any meaningful data for such close calls.

Actually, in line with a small test I ran on cruisers. I did not check the amount of damage they did, but I did compare time it took for cruiser gun to kill a "dummy". Did not notice any difference between no armour, pierced armour, and slightly-not-pierced armour. Well, to be fair with non-pierced armour dummy did manage to escape once, but still.

 

[myzael]

If piercing is lower than armor, the formula is (100% - <weapon's armor piercing> / <enemy's armor>) * -90%. As the damage reduction is zero at equal piercing/armor, it can't go any lower when piercing exceeds armor. This is why piercing > armor increases the chance of critical hits instead (albeit not in a scaling manner).

In what manner then? It would be good to add both formulas to the wiki.

 

[ecpgieicg]

If piercing is lower than armor, the formula is (100% - <weapon's armor piercing> / <enemy's armor>) * -90%. As the damage reduction is zero at equal piercing/armor, it can't go any lower when piercing exceeds armor. This is why piercing > armor increases the chance of critical hits instead (albeit not in a scaling manner).

How did you get the formula please?

 

[SigurdStormhand]

I would. That's always how I build CL. Armor is always maxed. And that's why CAs are useful despite of not being able to screen BBs -- 'properly' built CLs can't pen each other.



In my games using Black ICE, AI DDs tend get one shot by my BBs/BCs. But very good DD costs 2k ish IC while good CL costs almost 10k. The mod restricts max dockyard per line to 3 regardless of ship type. Plus some additional modules that add % changes to IC. So production matters a bit more. But the same idea still applies to vanilla HOI4.

The value of cruiser armour is in facing other cruisers rather than "true" capital ships. No cruiser built either in the Interwar period or during the war it self could absorb hits from the mains guns of a battleship or battle cruiser. I use armoured heavy cruisers to lead patrol fleets. The better armour helps to protect them should their screen ships go down (usually a light spotting cruiser and two DD's). It's an efficient patrol groups for attacking escort fleets or convoys. Cruisers in the battle-line are useless, though, unless you need something to screen a carrier and all your BB's are dead.

 

[ecpgieicg]

The value of cruiser armour is in facing other cruisers rather than "true" capital ships. No cruiser built either in the Interwar period or during the war it self could absorb hits from the mains guns of a battleship or battle cruiser. I use armoured heavy cruisers to lead patrol fleets. The better armour helps to protect them should their screen ships go down (usually a light spotting cruiser and two DD's). It's an efficient patrol groups for attacking escort fleets or convoys. Cruisers in the battle-line are useless, though, unless you need something to screen a carrier and all your BB's are dead.

Yes. Due to the way HOI4 targeting system works, lightly armored ships considered as capitals are dead weight in doomstack vs doomstack fights. You do need to take them off. I wish HOI4 naval game is more intense. Currently, probably no one feels the need to micro their fleets unless it is for roleplaying.

 

[sterrius]

Yes. Due to the way HOI4 targeting system works, lightly armored ships considered as capitals are dead weight in doomstack vs doomstack fights.

not really, a heavy cruiser or BC´s can have quite a good dodge chance vs heavy guns if surface visibility and speed are kept high enough.
And the difference in hit chance can be quite brutal.
For a BB to keep up on dodge they have too give too much firepower.
Losing the whole point of having this kind of ship

A heavy cruiser can have armor 6-8-10 and 12.
Keeping himself above the light gun piercing value is essential so its a race of armor vs guns here. Doctrines + Military staff do affect Heavy cruisers and can give quite a bit of armor.

Also by having 1 heavy gun, 1 light gun and maybe 1 torpedo. Its the only ship that can do 3 attacks at same time. With such low values to hit something having a extra die roll is pretty big and very very deadly vs ships that lack capitals. (As the heavy gun will aim at the smaller vessel and 1 hit = big dmg for a DD/CL).

The BC armor is a race vs the Heavy Cruiser main gun. And the BC can get help from doctrines and military staff.
Also don´t forget depending on the area ships get bonuses/debuffs.

Light cruisers have -10% speed, attack and evasion on deep oceans. That is most of the atlantic and Pacific.
While Heavy cruisers lose -20% attack, Defense and Movement on fjords and archipelagos. (Indonesia on the pacific and the Baltic sea).


For germany and Japan i would heavily rely on Heavy Cruisers to make the "Snipal cord" of the navy.

 

[desphorin]

lightly armored ships considered as capitals are dead weight in doomstack vs doomstack fights

Idk man, light attack CA with nil armour still works very well and can dodge most of the heavy attack with its high speed

 

[sterrius]

Idk man, light attack CA with nil armour still works very well and can dodge most of the heavy attack with its high speed

not worth having a CL or CA without armor. The gain in evasion does not offset the benefits of armor I.
Also most majors have armor II in 1936. But no country have Gun III (1940 tech). Reason its also worth going for armor II as a pretty good amount of ships is running around with old guns.

Armor III > any light gun. So you're pretty much immune. Its a very good tech to research .

Armor IV is only if the enemy on top of having the 1944gun he also have +2 ammo techs. (Increase piercing to 10.8).

CL
light gun I Piercing = 5.5 (6.6 with ammo bonus)
Light gun II = 7 (8.4 with bonus)
III = 8 (9.6 with bonus)
IV = 9 (10.8 with bonus)

Ammo 1 = 1937 tech (Useless on its own for piercing purposes).
Ammo 2 = 1942 tech

CL armor
I = 6
II = 8
III = 10
IV = 12