pcasey
Junior Member
Posts: 58
|
Post by pcasey on Jun 1, 2019 11:54:54 GMT -6
There exist different size shells.
11", 12", 13", etc
There exist different gun qualities
-2, -1, 0, +1
There exist different kinds of ammunition
AP, SAP, HE
There exist various technologies that purport to make my shells do more damage
Lydite busting chargets etc
In the general case, how is it possible to tell how much damage any specific shell does e.g. what is the bursting effect?
How is it possible to tell the armor penetrating value of things like SAP which should have lower penetration and AP but a larger bursting charge?
|
|
|
Post by orkel on Jun 1, 2019 12:13:39 GMT -6
The basic bursting charge strength seems to be related to the shell weight in the gundata.dat file:
c sw ROF mr 2 15 25 4 3 15 25 8 4 32 20 10 5 63 19 11 6 108 18 12 7 172 16 13 8 276 15 14 9 365 14 15 10 500 12 16 11 666 11 18 12 864 10 20 13 1200 09 21 14 1372 09 22 15 1688 08 24 16 2048 08 26 17 3000 08 30 18 3500 08 32 19 3800 07 33 20 4100 07 34 Caliber, shell weight, rate of fire, and maximum range.
So it gives a rough comparison of the "power" of the shells (20 inch has twice the weight compared to a 16 inch, for example, so I'd assume very roughly twice the damage) The actual damage that the shells do vary a lot depending on hit location, RNG, tech level, etc.
|
|
|
Post by christian on Jun 1, 2019 14:05:34 GMT -6
The basic bursting charge strength seems to be related to the shell weight in the gundata.dat file:
c sw ROF mr 2 15 25 4 3 15 25 8 4 32 20 10 5 63 19 11 6 108 18 12 7 172 16 13 8 276 15 14 9 365 14 15 10 500 12 16 11 666 11 18 12 864 10 20 13 1200 09 21 14 1372 09 22 15 1688 08 24 16 2048 08 26 17 3000 08 30 18 3500 08 32 19 3800 07 33 20 4100 07 34 Caliber, shell weight, rate of fire, and maximum range.
So it gives a rough comparison of the "power" of the shells (20 inch has twice the weight compared to a 16 inch, for example, so I'd assume very roughly twice the damage) The actual damage that the shells do vary a lot depending on hit location, RNG, tech level, etc.
really shows nothing because we have no idea how research effects this at all also what quality is the gun because that dictates the range
|
|
pcasey
Junior Member
Posts: 58
|
Post by pcasey on Jun 1, 2019 14:19:22 GMT -6
What about difference between ap, sap, and he?
Logically the improved armor penetration of ap relative to sap should come at a reduction in damage potential ( smaller bursting charge ), but I’d like to know exactly how much less penetration I am trading away and how much more damage it will do if it does penetrate.
|
|
|
Post by mycophobia on Jun 1, 2019 17:42:51 GMT -6
What about difference between ap, sap, and he? Logically the improved armor penetration of ap relative to sap should come at a reduction in damage potential ( smaller bursting charge ), but I’d like to know exactly how much less penetration I am trading away and how much more damage it will do if it does penetrate. Unfortunately I can’t find the post on top of my head, but i remember reading form the team that clarified that SAP shell’s damage/pen trade off. (I very vaguely remember being about 20% less pen for 20% more burst but I could be wrong.) You can try to do a forum search and you might be able to locate that post. I will edit this post later if I can find the post I speak of
|
|
|
Post by aeson on Jun 1, 2019 18:14:47 GMT -6
Unfortunately I can’t find the post on top of my head, but i remember reading form the team that clarified that SAP shell’s damage/pen trade off. (I very vaguely remember being about 20% less pen for 20% more burst but I could be wrong.) You can try to do a forum search and you might be able to locate that post. I will edit this post later if I can find the post I speak of
Specifically, the post linked says that SAP shells have roughly 50% to 75% of the penetrative power of AP shells and have a "larger" bursting charge; how much larger is left unspecified.
|
|
|
Post by bcoopactual on Jun 1, 2019 18:38:44 GMT -6
[Edit - I was typing this while aeson posted so go with his post for SAP penetration since it comes from the developers.] No specific numbers are given for shell damage. It's just general thumbrules. Shell damage is proportional to caliber. For the same tech level and type of shell a larger caliber shell will always do more damage than a smaller caliber shell if they both penetrate and explode. Gun quality has no effect on shell damage other than determining whether the shell fully penetrates or not. Gun quality affects range and penetration (and indirectly accuracy in some cases). There is a general improvement in damage as tech level goes up but the specifics are unknown. I don't know if it's the same percentage each time or not (but I doubt it). Obviously AP shells do the least damage but have the greatest penetration and HE shells are the opposite. But I don't know specific numbers. You can probably use historical examples and compare bursting charges to get an idea. The development team has done their homework so they are familiar with those kinds of details although being a game you can't expect they got it exactly equivalent to historical examples or even which shells they used to compare. Information on SAP is pretty scarce online. The one article I saw that talked about penetration was about the SAP shells for Bismarck. It said they had about 3/4 the penetration capability of the full AP shell. So somewhere between 70-80% is a good guess. Assuming the HE L/4,5 base fuze shell listed for the 38cm SK C/34 ( Bismarck-class) on the navweaps sight is the SAP variant then the bursting charge for that is approximately 72 lb compared to roughly 41 lbs for the AP shell. So expect damage to be a little less than double for the SAP shell compared to the AP. For reference, the bursting charge for the nose fuse HE shells was about twice again the SAP shell at 141.5 lbs. So without checking, I couldn't tell you what the ratio was for American, British or Japanese shells or even if they historically used SAP but it's probably not a bad assumption to make that in-game SAP shells do about twice the damage of an AP shell and HE shells do about twice the damage of an SAP shell (and about 4x the damage of an AP). Others can chime in if they have seen better or more accurate numbers confirmed by the developers. Sorry I can't give you more specifics.
|
|
|
Post by williammiller on Jun 1, 2019 21:17:47 GMT -6
This is a complicated subject matter...I have studied and modeled explosives and ballistics for 3 decades now and I still don't remotely know everything :-)
As a general rule of thumb, naval shells will do relative damage equal very roughly to their difference in mass to the 0.67 power: i.e. (Shell-A-mass/Shell-B-mass)^0.67 = relative damage of shell-A compared to shell-B. So doubling the weight of the shell gives about 1.6x greater damage, 4x the weight is about 2.5x the damage (assuming they both penetrate). There are other modifiers, but this gives a ballpark idea of the differences.
In our 'real-life' history German SAP shells were a bit different in some ways than the so-called 'SAP' shells used by other nations...in effect they were somewhat closer to a 'normal' AP round in performance relative to such rounds used by other nations - but in the RTW game all SAP shells are treated with the same formulas since players are actually 'rolling their own' history.
|
|
|
Post by rimbecano on Jun 2, 2019 2:24:51 GMT -6
As a general rule of thumb, naval shells will do relative damage equal very roughly to their difference in mass to the 0.67 power: i.e. (Shell-A-mass/Shell-B-mass)^0.67 = relative damage of shell-A compared to shell-B. So doubling the weight of the shell gives about 1.6x greater damage, 4x the weight is about 2.5x the damage (assuming they both penetrate). There are other modifiers, but this gives a ballpark idea of the differences. Out of curiosity, what's the metric for "damage" here? I'd expect something like energy deposited in the target, except I'd think that would scale directly with mass (assuming that all shells of a given type (AP, SAP, HE) have the same proportion of their mass dedicated to explosives). Or is it something like the total area of shrapnel holes below the waterline, or something like that?
|
|
|
Post by aeson on Jun 2, 2019 8:07:53 GMT -6
I'd expect something like energy deposited in the target, except I'd think that would scale directly with mass (assuming that all shells of a given type (AP, SAP, HE) have the same proportion of their mass dedicated to explosives). Explosion energy isn't all delivered at a point but rather over a wavefront, and once the energy density on the wavefront falls below a certain level it's not really doing that much to a ship - especially armored portions or heavier structural elements. If you have an explosive that produces a perfectly-spherical explosion, increasing the size of the charge by a factor of x results in an explosion that has the same wavefront energy density at about x 0.5 times as far away, so if we're working in an infinite empty space doubling the explosive charge increases the distance at which the wavefront will deliver enough energy to cause damage by a factor of about 1.414. Confine that explosion within a structure and maybe assume it's at least slightly shaped (rather than perfectly spherical) to begin with and you can expect the wavefront to carry enough energy to be damaging a bit further, at least in some directions, than with the perfectly-spherical model, which is probably why the exponent williammiller stated is 0.67 rather than 0.5.
|
|
|
Post by williammiller on Jun 2, 2019 10:30:16 GMT -6
As a general rule of thumb, naval shells will do relative damage equal very roughly to their difference in mass to the 0.67 power: i.e. (Shell-A-mass/Shell-B-mass)^0.67 = relative damage of shell-A compared to shell-B. So doubling the weight of the shell gives about 1.6x greater damage, 4x the weight is about 2.5x the damage (assuming they both penetrate). There are other modifiers, but this gives a ballpark idea of the differences. Out of curiosity, what's the metric for "damage" here? I'd expect something like energy deposited in the target, except I'd think that would scale directly with mass (assuming that all shells of a given type (AP, SAP, HE) have the same proportion of their mass dedicated to explosives). Or is it something like the total area of shrapnel holes below the waterline, or something like that? Its a very general comparison metric, designed to compare average statistical -relative- damage from different weights of shells of the same type striking a ship. There are much more detail formulas one can use for more specific applications, but this one suffices for what it is intended for w/o being cumbersome.
Just for fun, as an example of perhaps too much detail, I once created a formula for a role-playing game that determined how many fragments (or probability of a single fragment hit) would strike a target of X area at Y range given the grenade throwing off Z number of fragments & the damage a fragment would cause in game-terms (and yes I had data for the number of fragments each grenade typically exploded into, their size and initial energy, and their ballistic CE ) - it was realistic, but in practice it slowed the game down so much that it was hardly if ever used .
|
|
|
Post by dorn on Jun 2, 2019 12:12:51 GMT -6
Out of curiosity, what's the metric for "damage" here? I'd expect something like energy deposited in the target, except I'd think that would scale directly with mass (assuming that all shells of a given type (AP, SAP, HE) have the same proportion of their mass dedicated to explosives). Or is it something like the total area of shrapnel holes below the waterline, or something like that? Its a very general comparison metric, designed to compare average statistical -relative- damage from different weights of shells of the same type striking a ship. There are much more detail formulas one can use for more specific applications, but this one suffices for what it is intended for w/o being cumbersome.
Just for fun, as an example of perhaps too much detail, I once created a formula for a role-playing game that determined how many fragments (or probability of a single fragment hit) would strike a target of X area at Y range given the grenade throwing off Z number of fragments & the damage a fragment would cause in game-terms (and yes I had data for the number of fragments each grenade typically exploded into, their size and initial energy, and their ballistic CE ) - it was realistic, but in practice it slowed the game down so much that it was hardly if ever used . Quite suprised that is so much time demanding calculation that it can slowed game.
|
|
|
Post by aeson on Jun 2, 2019 12:30:50 GMT -6
Quite suprised that is so much time demanding calculation that it can slowed game. The probability of being hit by a fragment ought to be inversely proportional to the square of the distance to the grenade even before you factor in things like air resistance and gravity, so I could certainly see it being time-consuming enough to slow down a game - especially if, seeing as you're computing probabilities, this is only prep-work so that you can then go on to roll for hits and damage. Much easier to say that anyone within X distance takes Y damage while anyone beyond X distance is unaffected or something like that.
|
|
|
Post by williammiller on Jun 2, 2019 14:16:14 GMT -6
Its a very general comparison metric, designed to compare average statistical -relative- damage from different weights of shells of the same type striking a ship. There are much more detail formulas one can use for more specific applications, but this one suffices for what it is intended for w/o being cumbersome.
Just for fun, as an example of perhaps too much detail, I once created a formula for a role-playing game that determined how many fragments (or probability of a single fragment hit) would strike a target of X area at Y range given the grenade throwing off Z number of fragments & the damage a fragment would cause in game-terms (and yes I had data for the number of fragments each grenade typically exploded into, their size and initial energy, and their ballistic CE ) - it was realistic, but in practice it slowed the game down so much that it was hardly if ever used . Quite suprised that is so much time demanding calculation that it can slowed game. I should have been clearer - This was for a pen-and-paper rpg, not a computer game rpg
|
|
|
Post by abclark on Jun 2, 2019 19:34:05 GMT -6
I should have been clearer - This was for a pen-and-paper rpg, not a computer game rpg That does make a bit of a difference. I ran into that problem when I wanted more "realistic" hit probabilities/penetration/damage in tabletop naval gaming. Even if you limit it to 2kyd range brackets, the number of variables goes up exponentially the deeper you get down the rabbit hole. I eventually realized that the only way to make an even remotely accurate system that was within the same universe as a playable system it would have to be computerized. Of course at that point you can get really crazy with it; tables for how each individual shell will interact with different armor types, at all possible angles, with different levels of penetration, etc. I'm still wondering how deep that particular rabbit hole goes
|
|