How ship armor works (Full Version)

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Fallschirmjager -> How ship armor works (8/6/2012 9:00:39 AM)

I am editing a scenario and messing around in the editor creating my own ship. I have figured out most everything except some of the inner working of how armor works.
I know that armor is displayed in 'mm' unit as a measure of thickness. Since the figures for none of the ships are exact I am guessing there was a bit of number fudging since there are only four measures of armor thickness when a real ships had dozens.
These are belt, deck, tower and turret.
I am also guessing that it is a representation of metal quality.

That is all fine and good.

I realize each device has a penetration rating in 'mm' and that in combat each shot fired when it hits is a dice roll on whether it penetrates or not assuming it has the ability to do so.

My real question is how exactly this armor thickness works. Is armor all or nothing or do armor have some sort of hidden rating in damage prevention?

i.e. Let's say that a IJN gun with a penetration of lets say...400 mm shoots a shell at a USN ship with 350 mm of belt armor. The dice are rolled and it is a belt hit and the roll number lets it be a penetrating hit.

Is it a simple check to see if the weapon penetrates or not and then damage is calculated...or...since there is a difference of '50' does armor provide some kind of damage protection?

In case I am not being clear. Lets me use an example.

Let's say I made two ships. Both are the same tonnage, durability etc. Exactly the same.

The only difference is their armor. Ship A has 1 'mm' everywhere. Ship B has 450 'mm'

They are both shot with a weapon with a penetration rating of 500 (same effect rating). Both ships are penetrated. Does the higher armor rating on ship B prevent more damage than the paper thin armor on ship A?

If a weapon penetrates is the only number that matters next the ships durability rating?

Thanks for any answers. I have been wondering this for the longest time now.

tocaff -> RE: How ship armor works (8/6/2012 12:16:07 PM)

Actually you example won't work. An AP shell hits and goes through a thin skinned ship without going off unless it hits something such as a propeller shaft, the engine, etc. Think of Taffy 3 and the Japanese with their big guns.

Alfred -> RE: How ship armor works (8/6/2012 2:23:50 PM)

Read this thread. Post #2 in particular.�


Fallschirmjager -> RE: How ship armor works (8/6/2012 9:27:41 PM)


ORIGINAL: tocaff

Actually you example won't work. An AP shell hits and goes through a thin skinned ship without going off unless it hits something such as a propeller shaft, the engine, etc. Think of Taffy 3 and the Japanese with their big guns.

My example won't work in real life but I simplified it for game terms to ask a question.

Fallschirmjager -> RE: How ship armor works (8/6/2012 9:29:24 PM)



Read this thread. Post #2 in particular.�


That appears to answer it. So it looks like it is a die roll on penetration and then the next roll is effect vs durability.

Nikademus -> RE: How ship armor works (8/7/2012 5:27:23 PM)

except there's no die roll to determine maximum penetration. Thats a hard figure. Has been that way since UV.

US87891 -> RE: How ship armor works (8/8/2012 10:08:43 PM)


ORIGINAL: Nikademus
except there's no die roll to determine maximum penetration. Thats a hard figure. Has been that way since UV.

maximum penetration comes from the database for a weapon, so there is no die roll. Penetration falls off as a function of range. The longer the range, the less the penetration and there is some die roll fuzzy math to see what happens. And there is a calculation of falling angles and some die roll fuzzy math about if it hits the hull or the deck. so there is a die roll to determine penetration, you won't see it when you are close, where it resolvs to 80+%.[:)]

Norm3 -> RE: How ship armor works (8/9/2012 3:25:41 AM)

it would be so much simpler if the answer were 42

Shark7 -> RE: How ship armor works (8/9/2012 4:49:23 PM)



it would be so much simpler if the answer were 42

The answer is 42...always. [;)]

kmitahj -> RE: How ship armor works (8/11/2012 10:01:31 PM)

Have not much to say about Admiral Edition in particular (not enough experience nor time spent) but for Classic WitP I was always convinced - based just on rather long player experience - that shell vs ship armor interaction was reduced here to simple test comparing (database listed) penetration to same way listed armor value. The only randomness - I thought - is in the moment when engine decides which armor value (belt, deck or tower)is to be used to compare against gun device penetration. Well, I have to admit I was wrong thinking that way - at least wrong when it comes to details of the implementation of the ship armor penetration model. However even taking into account until now unknown to me implementation details I think that unfortunate consequences of classic witp penetration model still hold.

So before going into such implementation details first few words what unfortunate consequences I had in mind. Well, I always thought that such overly simple test for armor penetration is one of major weaknesses of that fine game. It not only removed good part of realism form naval battles but also invited players to all sorts of gamey moves. It is in human nature to gamble (in this case to gamble against game engine) when we belive we can trick the odds to be on our side. And no matter if going againt LBA, shore CD guns or enemy surface TF of known composition predictability of penetration-vs-armor model let the players choose their forces in the way which let them heavily reduce if not outright avoid risk of penetrating hits (jap BB decks immune to 500lb bombs, allied CA mostly immue to shooting of punny jap CD 5.5 inchers, BBs basicaly immune from CA fire, just like allied CA immune from crapy jap CL guns). Sure such "immunity" wasn't (fortunately!) 100% proof: sooner or later raising experience of 4E pilots was going to give them a chance to drop deadly 1000 or 2000lb bombs and in naval battles there was always topedo attack factor to take into account. And besides even non-penetrating hits were supposed to make some minor damage. I've read on the forum horror stories of BBs burnt to the waterline by rain of nonpenetrating 500lb bombs though I have to say, I never have seen this myself (good!), nor manage to inflict it on one of my opponents (pity! [;)]).
Overall my humble opinion was that simplicity and predictability of armor penetration model promoted player's gaminess and precluded results like that in the First Naval Battle of Guadalcanal where allied CAs nailed japan BB (surely Hiei was just second class BB, and still she was just severly wounded after naval brawl and doomed only after series of air attacks).
Anyway I surely hoped that weakness to be amended in AE - can't say if it was and if so to what extend it was done but if I read correctly posts of knowleadgeable people involved in AE development it wasn't changed much. Surely some changes with damage distribution had to be made due to new damage categories. But was armor penetration model itself changed? I dunno. If not it may be interesting to look at the details of armor penetration model in Classic WitP...
After reading US87891 comments and beeing - I must admit - rather sceptical about them I tried to decipher the details on my own. However I have to stress here that: first they (the details listed below) are prone to misread and certainly not complete, and second, even if they are mostly right - as I hope they are - they are directly relevant only to Classic WitP. Anyway here they go:

First to note is that there is apparently single procedure is handling ship hits by all kind of devices: from mines and torps through guns up to bombs and aircraft cannons. One of first relevant things done in that procedure is classifying the hit as one of three generic types:
  • To type one belongs mine and torp hits. They are always tested against belt armor and has no chance to damage ship guns or other device mounts (not a big surprise here). Special feature is for hits of that type Penetration is tested against Random(BeltArmor) value meaning even small mine devices have some chance of achieving penetration.
  • Hits of type two (lets call them side hits) contain almost all gun hits (Navy, DP, ArmyWeapon, AA-guns; with only one exception I'll talk in a second) plus PGM and rocket hits (yes I know the later are defunct but present in the code) and lastly aircraft cannon hits.
  • To type three (gonna call them top hits) belong all bomb device hits (besides GP bombs the code has second apparently unused bomb device type slot - planned for SAP bombs I guess?) and NavyGuns hits shot at long range. Long range NavyGun fire (long range here is defined as 66% or more of NavyGun listed MaxRange value) is that only exception mentioned above.
It is important to note that belonging to side- or top-hit class does not determine yet 100% that they will be tested against belt or deck armor respectively. There is for example 20% chance that top-hit penetration will nevertheless be tested against belt armor (it is to represent mostly near misses I guess). Similarly there are chances (for gunes exact numbers depend on the range in relation to the shooting gun's MaxRange) that side hit will go against ship's deck armor.
Also both side- and top-hits have first a chance to hit one of ship's device turret mounts and thus be tested against that turret mount armor (and/or against Tower armor). Because for device mounts there is no separated values for side and top turret armor when testing against top-hits procedure doubles Penetration before comparing it against turret armor. Effectively it is equivalent to assumption that turret top armor is half of its side armor.

Now taking closer look at values used in penetration verus armor tests. For armor the value tested seems to be almost always (two exceptions were mentioned above) the value listed by scenario designer. For Penetration however things are more complicated. For example for bombs there seems to minimum penetration enforced based on bomb's Effect value and aircraft class (like F, FB, DB, LB) delivering the bomb (a strange part for me - I guess there is here assumed implicit relation between AC class droping the bomb and bomb's kinetic energy at the moment of hit). Apparently if bomb listed Penetration is less then such calculated minimum its beeing replaced by it.
For most interesting case of guns - NavyGuns especially - procedure goes quite long way and calculates for them two separate Penetration values one - one can guess - to be used in test against deck armor, another against belt armor. First procedure scales - as US87891 noted above - Penetration listed by scenario designer in function of range. However I see big issue at that point - that is assuming I have read it correctly. Don't want to pretend I'm particuraly good in physics (well, I would dare to pretend I was quite good in it in my youth but that times are long gone [:'(]), nor that I do understand all that myriad complicated empirical formulas used to estimate gun penetration abilities but what I dare to say is that "scaling" performed here - again if I have read it right - is pure nonsense! What it does is just linear scaling of Penetration value with range in such way that the Penetration at gun's MaxRange is literally zero. Physically it equals to situation where shell hiting enemy ship at MaxRange is touching its armor with zero speed (zero kinetic energy if you prefer) - just nice, gentle touchdown at the end of shell trajectory.; yeah, no doubt about it! [:D] Such linear scaling would make at least some sense for AA shooting (kinetic energy goes into potential one) but for naval fire where virtually all permament loss of kinetic energy comes from air drag...
The thing which somewhat mitigates the problem here is that engine rarely if ever allows for naval battles to be conducted near the MaxRange value of big NavyGuns. First most battles in Classic WitP were night ones, second even in day encounters I don't remember shooting at ranges much above 21 kyds - not saying it can't happen, it is separate question to invetsigate if there is any built-in limit for max range of naval fire.

Getting over that sad point... procedure uses such scaled down Penetration to find out DeckPenetration and and BeltBenetration values. Calculations for both values looks very similar so lets see it only for BeltPenetration. First hit angle is estimated. Procedure chooses one of three linear formulas (in all cases Range is expressed in kYds [tousends of yards],and produced angle is in degrees):
1. HAngle = 1.14 * Range - 4.0
2. HAngle = 1.8 * Range - 7.2
3. HAngle = 2.5 * Range - 8.5
Choice between them is made based on listed Effect of gun device in such way that for typical database values third formula is used for all heavy BB guns (12in and above), second for medium gunes (mostly CA 8inchers) and first for all smaller guns (basically 6in and below). From myself I can only add: it's a pity there is no randomization of hit angle here (other then possible randomness in selecting range of shooting that is). There are countless factors which can not be covered precisely but could be bundled into such random component. Having the hit angle next obliquity factor is calculated. If I got it right formula looks like that:
ObFactor = 0.825 * COS(HAngle)^1.333
where COS is cosinus of the angle estimated above and "^" means "to the power of". At last procedure multiplies Penetration by that Obliquity Factor scaling it thus further down. The only difference between calc for DeckPen comparing to the above for BeltPen is - to be expected - use of (90-HAngle) value as an argument of cosinus function in formula above.
Thus here we have DeckPen and BeltPen values (note again that these values are used only for gun device hits). For any given gun hit one of them will be used to compare against corresponding armor value. Choice which one will depend mainly on random die rolls and range of fire as mentioned above.

So though armor penetration details turned out quite a bit more complicated - assuming I'm reading them right - main objection still stands (IMHO of course). That is model's simplicity reduces realism of naval warfare (subjective opinion I know) and its predictability invites players gaminess. Taking Penetration and Armor values from database I know for sure that armor will be no less then listed there (with two irrelevant exceptions described above) but Penetration for sure not greater, likely significantly lower then listed and with ships modeled as some old-fashioned ironclads or maybe rather medieval knights fully covered by armor with no vulnerable spots...
well, we got what we deserve I guess [:'(].

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