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**Jester-PFG** · 12-08-2022, 02:55 PM

Before I get to my thought processes, I'd like to give a heads-up that it's going to get a wee bit nerdy in here.

Design rationale

The long and short of this, I wanted to make some advanced rules for vehicular combat in Chronicles of Darkness and have deep and nuanced mechanics for tanks and AFVs. As a part of my "guiding vision" I considered the following:

The advanced rules would build upon, but not replace the existing rules if I could: no replacing the wounding system. It would be best to continue using the structure, durability, and size scores where possible.
I would be trying to go for accuracy and maintaining "tactical correctness" rather than going for "rule of cool" or what would provide the most dramatic uncertainty.
With a few exceptions, such as the use of nuclear weapons, the intersection of the supernatural with armoured fighting vehicles (such as use of Contracts such as Changeling Hours in Changeling: The Lost or "The Marionette" in Geist: The Sin Eaters) I would consider out of scope. I felt that this should be left up to each specific table to determine, as this can greatly influence the "genre" of their game.
To reduce the likelihood of favouritism, I would opt for a data-driven approach, and work on creating algorithms or procedures to transcribe real-world data to in-game units.
Game balance would be achieved by ensuring vehicles of comparable era, purpose, role, and capability are used on opposing forces, rather than trying to nerf or buff. I call this philosophy "apples to apples balance" or the use of like with like.

Establishing a baseline

The first thing I needed to do was establish a baseline, because vehicle armour value would drive damage values. Armour penetration is an extremely niche science, and you could write several Ph.D theses on it alone, and many of the precise details of the projectiles are classified. So to make it simpler to convert real world metrics to the game, I decided it would be best to use Rolled Homogenous Armour equivalency which is a common benchmark used in the real world. Vehicle armour could be considered the equivalent of cover, using the rules for damage to it (ignore all weapons that don't have a damage rating equal to or greater than its Durability) [Chronicles of Darkness, Core Rulebook, P.91].

I decided to start with an .30-06 M2 Armour Piercing Round (MIL-C-1617A), which is publicly available. The document for MIL-C-1617A states that the M2AP round must average at least 0.42" deep into a 7/8" rolled homogenous armour (MIL-A-12560) plate at 100 yards. In practice, an M2AP round can sometimes punch through and sometimes be stopped by a 13mmRHA plate. Chronicles of Darkness states that a .30-06 rifle is Damage 4, AP0 [Chronicles of Darkness, Core Rulebook, P.268]. Armoury 1st Edition is incompatible with 2nd, but suggested a value of AP3 for weapons of its calibre when firing "Armour Piercing" ammunition [Armoury 1st Edition, P.82]. From this, we can determine that a .30-06 M2 Armour Piercing Round would be in the realm of 4AP2 or 4AP3.

By comparison a 5.56x45mm NATO M855 (SS109) Penetrator Round, while not considered armour piercing, can reliably punch through a 1/4" thick structural-grade A-36 steel plate placed vertically at 100m. Chronicles of Darkness suggests that Durability 3 represent objects made of steel or iron [Chronicles of Darkness, Core Rulebook, P.96]. 2nd Edition suggests that a 5.56x45mm Assault Rifle is Damage 3 AP 0 [Chronicles of Darkness, Core Rulebook, P.268].

So I decided to approximate things:

Mild or structural steel plate (A-36 Structural Steel) could be thought of as being the equivalent of one quarter of the protective value of high-strength rolled homogenous steel plate (MIL-A-12560), but I rounded it up to half to make the math simpler since human beings are good at determining half. If greater resolution is desired, it could be reduced to the original value and different grades, such as high strength steel, high hardness steel, face-hardened alloy steel, or high-strength steels used in automotive applications (such as truck frames) could be represented by changing the coefficient.
The chart of vehicle armour would start at 10mm, with Durability 7.
Because I wanted things to scale easily and make the math relatively simple, I decided to use a simple linear function to estimate them. Normally, I'd use linear interpolation but I figured what I could do would be to measure it in centimetres, multiply by one and a half, and add the minimum-1, then simply discard all fractions without rounding. This forms our baseline.

I chose doing this because after rounding off, this allowed the amounts of Durability to mmRHA to scale by alternately 1 and then 2 for each centimetre of thickness, which then works out to Durability 7 for the first centimetre, then 3 for each two centimetres beyond it. This allowed me to establish a 3cm thick ballistic grade steel plate as Durability 10, a 50cm thick ballistic grade steel plate will be durability 13, and so on and so on. I did this to scale linearly, and make it easy for someone to do it mentally, without needing a calculator. Again, there are more sophisticated ways of doing this but I chose the path of least resistance.

These estimates assume thickness relative to the surface normal. For line-of-sight thickness, simply repeat the operation for line-of-sight thickness. I've included the formula in my draft.

For measuring armour scores, I would use the largest non-inert values on the intended striking face.

Although no vehicles today use rolled homogenous armour primarily., it's still a common benchmark in explaining how difficult it is to penetrate the armour, even though nowadays we use spaced armour or composite armour. I added some simple "rules of thumb" to allow spaced or composite armour to be approximated based on their characteristics, which I've explained under Armour Types.

Edit on December 9th: Earlier I stated that the M2 AP round would punch through a metal plate. This has been clarified to state that while it can, it's not a guarantee. I also made a small mistake stating that no vehicles today use mmRHAe, what I meant instead was that no vehicles primarily rely on RHA alone. This has been fixed

**Jester-PFG** · 12-08-2022, 03:08 PM

Vehicular scale weapons and damage

Now that we have a baseline figured out, let's figure out how damage interacts with armour. In real life, armour and weapons have a relationship not at all unlike a pair of training partners: they grow with opposition. Throughout history, weapons have improved and forced armour or designs for survivability to improve, which then forces weapons to improve in a distributed, worldwide game of leap-frog.

The goal for this is simple, and works well with the existing cover mechanics: to avoid tracking large amounts of health (and needing to decide on health tracks), what I'm going to be doing is instead considering vehicle armour as cover for the squishy and vulnerable people on the inside, along with components such as the engine, the turret drive components and the gun breech, the fuel tanks and the ammunition stores their own objects, each with their own Durability, Size and Structure scores. This keeps the amount of math we're going to have to do down and makes it easier to stat up more vehicles in the future.

Western testing measures armour penetration by gauging the thickness of the armour plate, with the armour plate angled at 30 degrees and placed at set intervals away from the gun. In order to be considered a success, the rounds need to be able to penetrate the armour 50% of the time.

This gives us a couple ways to work our way forward. What we can do is we can convert the surface normal to line-of-sight thickness with a bit of basic trignometry if we have to. Although Chronicles is a Success system, we are using d10s which makes things easier and it's easier to simply use the number shown on the dice rather than roll entire handfuls of dice and count them up. From there, we can bear in mind that the average roll of 1d10 is 6, and work our way backwards.

For example, if we wanted to show a weapon that could penetrate 150mm of armour plate, placed vertically, by Western standards, we derive the thickness of the 150mm thick armour plate at 0 degrees by the steps above, which gives us Durability 28. A weapon that could penetrate it at <100m would need to roll a total (in terms of damage plus armour piercing) of 28 or more half the time. We can get the number by subtracting 6 from this total, which gives us 22. Therefore, the combined amount would need to be 1d10+22.

Of course, there's a perfectly good armour penetration mechanic in Chronicles already which we can take advantage of. I decided to do the same thing as I did above for armour and do the same for weapons, and create standardized bore sizes for different weapons, with different weapons resolving to differest sizes, and then the difference made up by the armour piercing value. This chart only is intended to cover medium to high velocity projectiles, so I needed to estimate them, since the game system itself, even Hurt Locker, leaves off at "Elephant Gun" as a 5L weapon. Although the diameter of the bullet is smaller, a .500 Nitro Express or even a .600 Nitro Express produces significantly less muzzle velocity and therefore less energy than a 12.7x99mm NATO (.50 BMG) M2 Ball round (~11.4kJ vs ~18kJ at both rounds' maximum potential, respectively). So I had to build off that. Please understand that this will countermand some of the tables in Armoury 1st Edition and Hurt Locker, but it is being done for the reason of realism, not for dramatic conservation.

To plot the damage characteristics of different bore diameters, I plotted some lines experimentally, with points for 12.7, 14.5, 20, 25, 30, 40, 50, 60, 75, 88, 90, 120, 125, 127, 155 and 406mm shells (I want to add battleships to my work at a future date, so I went as far as including a 16" shell), and tried to get them to align by process of trial and error. This involved some guesswork, but I decided to scale a 20mm shell relative to a 14.5mm shell. This would make a 20mm shell damage 8, a 25mm to be damage 9, and a 30mm to be damage 10, then continue from there via linear interpolation. This should represent the median damage that a shell should do assuming zero AP value for a medium to high velocity gun.

From there, we can then make up the difference using the Armour Penetration values. So for instance, let us say that there is a hypothetical 75mm cannon shell that has been established via testing in the wartime to penetrate 160mm of steel plate angled at 0 degrees, at a distance of 100m that we want to transcribe into Chronicles of Darkness. 75mm works out from the above to be an average of 19. 1d10+14 will place the median value at 19.

I would like to use mechanics for constraining minimums and maximums, however, I don't have any set mechanics for that and simply rely on 1d10 for 75mm and above, which allows performance to vary by about a third in either direction. For now I've tried to follow suit as much as I can in this manner; smaller weapons may use 1d5, or roll to score successes. Larger weapons, such as 155mm Artillery, or 5" Naval Guns may roll 2d10, or even 3d10 in the case of battleship guns. Multiple dice getting involved tends to change the distribution, since the more dice, the steeper the distribution gets, so this'll have to be something to evaluate further in the future; a good compromise is to use one standard deviation above or below as a margin for distributions that aren't linear, which accounts for roughly 68% of all results.

We look up the chart of bore diameters of medium to high velocity guns and see that for a 75mm gun, the damage base is 1d10+14.
We look at the measurement for 160mm of armour and see it is Durability 30.
Since the average roll of 1d10 is 6, and the damage base of 14 will only sum to 20, and that leaves us with a deficit of 10, we add the deficit via the Armour Piercing value.
The damage of this hypothetical shell is then raised to 1d10+14 AP10.
This means that 50% of the time, the damage characteristic of the weapon will be equal to 30. Since successes on the attack roll do not contribute to damaging cover, this will be enough to be equal to and overcome the 160mm of ballistic plate 50% of the time, mirroring the odds of successful penetration at a distance of 100m at that given range.
If DDO is factored in (in the next post) we readjust until DDO is taken into account.

Should the standardized rating be higher than the amount, what we can do is either the following:

I chose to add a new weapon characteristic, called "Low Velocity" which would count the Durability of modern armour as being double its normal durability, and then recalculate from there. This would allow me to represent older or ancient ammunition types, such as blackpowder cannonballs (because I've wanted to do 17th century artillery and cannons and muskets later on). If need be, it's possible to build on that for "Super Low Velocity" and "Extremely Low Velocity" which would quadruple, and then octuple the armour value respectively.
Reduce the amount of damage done to make up the extra.

Both options could be used depending on circumstance and context.

Note that in most of his books, R.P. Hunnicutt gives estimation for penetration taken at 1000 yards and 2000 yards, with homogeneous armour at 30 degrees obliquity [R.P. Hunnicut: Firepower - A History of the American Heavy Tank, P.211; Sherman - A History of the American Medium Tank, P.558]. We may be able to work our way backwards from these. Note that obliquity has greater implications than simply line of sight thickness, especially given that it takes advantage of older full-bore armour piercing shells' tendency to ricochet. However, this is a massive rabbithole that would start becoming complicated in a hurry, so the increased likelihood of causing ricochets on top of the increase of line-of-sight thickness is being ignored.

Although this isn't as reliable as Hunnicutt's research, it's possible to use War Thunder's data in interim, because it's neatly formatted, readily available, and is arranged at intervals that closely align rather than simply being at 1000m and 2000m. For now, that's what I've gone with for some of the values, in the interest of expediency -- more on that below, under "DDO".

**Jester-PFG** · 12-08-2022, 03:29 PM

Damage Drop Off

I added some extra rules for how air resistance makes rounds less effective as range increases. Again, this is intended to mirror real-life odds since distance is an important tactical consideration. Damage Drop Off is measured as slash-separated numbers, treating the air as cover at short, medium, long ranges and beyond.

An important consideration is that air resistance plays an important part in tank combat. Historically, a very big advantage of bigger tanks and casemate tank destroyers was not just that they could carry bigger guns, (in the real world, there are no "hit points") but rather, that their bigger guns retained their effectiveness over greater distances.

This has important game balance considerations, since simply making heavy tanks inflict more damage and lighter tanks inflict less doesn't necessarily capture the nuance that distance yields important consequences for different tanks, especially given that we've gone the distance to accurately mirror penetration. The same logic of simply reducing damage done by the lighter guns also doesn't capture the nuance that closer ranges tended to make up for lower muzzle velocities when it came to the odds of successfully punching through armour plate. The good news is that Chronicles of Darkness already has existing range brackets for short, medium, and long range (which can easily be extended to extreme ranges and beyond), so let's use this. I call this rule "DDO" for "Damage Drop Off"

The easiest way to do this is to recalculate damage for different ranges, and then change the deficit by penalising armour penetration first, then damage once armour penetration reaches zero, to determine how damage "falls off" for kinetic projectiles.

So let's return to our theoretical 75mm hypothetical cannon that penetrates 160mm of armour at 100m. Let's say that it has a range of 1000m/2000m/4000m, which, respectively, real world testing either provides as 140mmRHAe, 100mmRHAe, 80mmRHAe. First, let's slap an extra close-range bracket on it we'll call point blank, representing half of short range, to turn the ranges to PB/1000m/2000m/4000m, and recalculate the difference at each one. This gives us 0/-3/-7/-12, indicating that the gun will do:

1d10+14 AP10 at 0m to 500m,
1d10+14 AP7 at 501m to 1000m,
1d10+14 AP3 at 1001m to 2000m,
1d10+10 AP0 beyond 2000m.

We can continue to add or estimate more values beyond 4000m if need be by estimating DDO (easy way, just look at the difference between DDO, as many cannons could be fired indirectly as artillery. I chose to make it this way since the amount of penetration lost to aerodynamics is nonlinear. This represents a fairly simple way of doing it because only two numbers need to be added at a given range and all of it can be added up in the same roll to damage.

Thus, this establishes that distance for kinetic projectiles plays a significant role: survivability increases with distance, which increases the effectiveness of armour or decreases the effectiveness of kinetic armour piercing rounds such as AP rounds. HEAT, HE, HESH, and the other types of rounds which depend on stored chemical energy are not subject to this limitation.

Mechanics for thermobaric/fuel air explosives and different types of bombs are due later. For HEAT rounds, I reversed the order of precedence when resolving them: damage first, explosive force after, with HEAT rounds never having explosive force damage cumulative with the direct damage they inflict on a single target.

The blast radius of the US Navy Mark 7 16"/50-calibre Naval Guns' Mark 13 High Capacity Shells were estimated based on historical records of the Mk. 13 HC shells blowing down all the trees in a 400m radius when conducting shore bombardment during the Vietnam War, and were scaled according to the rules in the books. The rest of the explosive radiuses of the shells in my current draft are currently temporary and expected to change. They should not be considered final.

Ammunition Types

Ammunition types can at this moment be determined by using Hurt Locker as a bit of a baseline. At this moment I'm working on mechanics that would allow us to calculate blast radius, Damage and Force dice from charge and fragmentation mass.

In interim, I'll be working my baseline off some very rough estimates based on the scaling and relative masses of grenades from Hurt Locker, and a very approximate blast radius of HELLFIRE missiles, 155mm Artillery Shells, and a 2000-pound munition, with estimates taken from a very simplified handout from the UN Human Rights Office of the High Commissioner [https://www.ohchr.org/sites/default/..._Compared.pdf]. The Geneva International Centre for Humanitarian Demining has some information on case studies of casualties and the nature of injuries caused by mortar shells, which can have shells of explosive capacity ranging from the size of a few ounces of TNT to more than 4kg of explosive filler [http://characterisationexplosiveweap...0-mm-mortars/].

This is going to be really work in progress so I'll be continuing with this in what time I can get. Expect heavy changes to happen here as I go and tune the models.

**Jester-PFG** · 12-08-2022, 04:58 PM

Acceleration, Handling, and More

I decided to next take a look at acceleration. Generally, Chronicles of Darkness assumes that most vehicles may accelerate at a rate of 5m per turn, but or 10m per turn should the driver succeed at a Dexterity + Drive roll, penalised by the vehicle's handling modifier. Fast vehicles may accelerate at 10, and slow vehicles may only accelerate at 5m per turn regardless of the driver's skill.

Because this doesn't capture some of the granualarity of what I'd like to accomplish, what I've done instead is assume that each turn is 3 seconds long. This allows me to then determine acceleration by determining the vehicle's 0-60 time (if applicable) or the time it takes for a vehicle to reach its maximum speed, then averaging and converting the acceleration to a 3-second interval in metres per turn per turn.

Turn radius, I'm still working on. Formula One cars can usually turn at rates where the G forces incurred by the turn routinely get to multiple times the force of gravity at speeds well in excess of 350km/h (this is why Formula One cars often need dry-sump lubrication to prevent oil starvation), which establishes a pretty good upper limit, however we'll work our way backwards at a later date.

An easy way to do it is in interim is to do it GURPS style, with radius being equal to speed squared plus an adjustment factor. For tanks, the limiting on a tank's turning radius tend to be the tracks: too aggressive a turn, and the tracks can be "thrown." For now, some values have been placed in interim.

Turret Traverse Speed (TTS)

Because it can take time for tank gun turrets to traverse, I've also added an extra mechanic that dictates how many turns it takes for a tank turret to rotate through 90 degrees, and how many turns it takes for a tank gun to "identify" (or point) at a target. This I've expressed as two numbers or figures separated by a slash.

Some WWII tanks, such as the Panzer IV Ausf. J did not have electric drive for the turret traverse, because of late-war era shortages which forced the electric drive to be omitted: as a result they can take as much as 11 turns (representing 33 seconds of in-game time) to turn the turret 90 degrees, less depending on the gunner's Stamina. I've recorded this on Page 197 as of this revision.

This is an important balance consideration since it and the Strength of the loader bottlenecks how quickly a tank gun can be readied to fire, and also affects what direction the tank gun can be fired in relative to the hull facing at that point in time.

Accuracy and Target Differential Divisor (Acc and TDD)

During the Second World War, it wasn't impossible for tanks and tank guns to slug it out very long distances: a Nashorn armed with an 8.8cm L/71 PaK 43 claims a kill from 2,800m against a Sherman [Marko Pantelic, https://tanks-encyclopedia.com/ww2/n...4_nashorn.php]. The Hull of an M4A3 Sherman is 118" wide without its mud guards, or around 3m wide. To be able to land a hit within a circle inscribed within its width at that distance would require accuracy on the order of 1-2 minute of arc, which is approximately the accuracy of a good quality sniper rifle (in order to be considered "Match Grade" a rifle firing match grade ammunition must be capable of accuracy under one minute of arc).

Keep in mind that everything's relative: a +/-0.001" of variation on a 1" diameter shaft, is actually the same amount of tolerance as +/-0.1" of varation on a 100" diameter shaft. Given the size difference between the 8.8cm gun and a modern 7.62x51mm rifle, this indicates that the grades of tolerance on the 8.8cm gun are actually going to need to be much tighter than a match grade rifle!

The magnification of the tank's optics are also going to be as highly sophisticated, if not more complex than a rifle's of the equivalent era and offer greater magnification. So all that said, tank guns are very accurate, so simply slapping on a minimum size characteristic seems a little arbitrary, yet, there's a certain amount of size that these guns are designed to be turned on.

For this reason, I've developed a mechanic I call Accuracy and Target Difference Divisor. Accuracy representing the minimum size of a target that the gun can fire on without penalty, and TDD, which then divides the difference. These are intended to vary by range, so as to offer more realistic way of determining what targets are and aren't appropriate for a tank gun.

For example: a Tank Gun has a range of PB/1000/2000/4000, and has an Accuracy of 5/5/7/10, and a TDD of 1/1/1/2. This means that at point blank and short range, it may shoot at targets size 5 and over without penalty. However, at medium range, targets have a minimum size of 7, and take a -1 penalty for the difference if less. At long range, targets must be size 10 or take a -1 penalty for every 2 of the difference, rounding up.

So a tank gun firing at a target size 5 would take no penalties at point blank or short range, a -2 penalty at medium range, then -3 at long range, on top of the distance penalties of -1 and -2 respectively, but not inflict any penalty when shooting at a size 10 target.

I intend to use this to allow realistic targeting of tanks as a unit, or different components on a tank, such as the turret, or hull, or components such as the engine compartment or ammunition racks: in video games like War Thunder that's possible and expected because War Thunder makes it significantly easier, in real life these hits happened much more through luck and chance than by design.

Scattering and Circular Error Probable

Chronicles of Darkness is difficult to compute scattering for, since normally with systems that use the number shown on the dice and require it to be greater than or less than a set target number, it's easy to determine how much something failed by. With the Storyteller system, this isn't so intuitively done, so I'm still working on this - currently the mechanics I have in there are temporary.

To use a Circular Error Probable mechanic, what I've decided to do is take the circular error probable of a weapon, measured in metres, multiply it by percentile dice, and multiply that by 0.03, then roll directional dice of 1d8, representing north, northeast, east, etc, which for now is "good enough" but I may replace this at a later date. I've included an example, although the damage tables are all off since it was older and used temporary values.

**Iguazu** · 12-09-2022, 08:08 PM

Originally posted by Jester-PFG View Post

Howdy there,

I'm coming to Chronicles of Darkness from a background in Dark Heresy, GURPS High Tech 4th Edition and Phoenix Command Mechanised Combat System. . . .

I've played GURPS once and I don't remember the system and you're right, there are no hit-points.

I did create a vehicular-combat-system for the original WoD; hey, I wanted to run a World War Two game (Eastern-Front), where players had humanity and had to commit atrocities etc. And a few of my players were pro-German etc.

My background is Battletech, Cyperpunk: 2020: Maximum-Metal and Steel Panthers (DOS video-game). So, each cannon and vehicle had to have their unique armor and damage. I based a lot of it off the Vehicle-combat system from, Vampire: the Player's Guide.

At first, I had to use my judgement on how much damage was done; does an AP-round kill the entire crew and I apply remaining damage to all or just a few of the crew? Surely and HE-round with an area-of-effect would damage all the crew etc. I made a random-chart, which was a lot easier because I didn't have to decide.

**Jester-PFG** · 12-09-2022, 09:54 PM

Hello there Iguazu, I appreciate the interest! That's awesome to see that more people are interested in vehicle and vehicle combat, I'll definitely will need to take a look at the Vampire Player Guide's vehicle combat system, I very much like seeing how other people have approached the problem before.

At first, I had to use my judgement on how much damage was done; does an AP-round kill the entire crew and I apply remaining damage to all or just a few of the crew? Surely and HE-round with an area-of-effect would damage all the crew etc. I made a random-chart, which was a lot easier because I didn't have to decide.

Sure, I'd be more than happy to break this down a tiny bit for you with two examples of how I've handled it in my version. It's a little bit more complex, but I felt that it offered a little extra to give back in that it allowed for finer control in situations.

Gods of Iron uses a "module by module" system. Notice that each tank in the PDF has its own Durability and Structures chart, which includes the Turret and the different facings for it, the Hull and its different facings, but also Systems, which include the engine, ammunition hold, fuel tanks, and the gun breech (which are used to represent the turret traverse and elevation mechanisms as well as the gun). Most importantly, each individual crewmember is considered a module, so damage to crews is also something that I want to capture.

The way I've written it at this point in time is that whenever a weapon that has no bursting charge doing at least Damage 8 or more strikes something with Durability 3 or greater, it creates a spall, from causing pieces of itself and the armour to shatter, sending razor sharp shards of metal whizzing around the interior of the tank.

This spall is represented by doing damage dice equal to 1/4 of the damage characteristic of the weapon, and its blast radius is equal to a third of the weapon's damage, and depending on whether or not the damage has the "LV" (Low Velocity) modifier or not, this influences whether or not the damage dice also inherit the Low Velocity trait. ("Low Velocity" simply doubles the armour values, unless they are non-ballistic). Spalls are limited by the Durability of the armour they hit, which I did intentionally so that in some cases, armour piercing tank shells that have a penetration fuse can pass through lightly armoured vehicles such as civilian vehicles without causing much damage, just as they would in the real world.

Depending on the presence of a Penetrator with Enhanced Lateral Effects (PELE), this is done a bit differently, but in this case, I'll pick an example from WWII:

The vehicle takes the initial damage, and then depending on where it's hit, the blast affects other areas in the tank. If an area is targeted, the shell hits the targeted module after resolving cover. In the future, I want to have "Confined Space" mechanics to magnify the effect of a blast that's been contained but that will have to be in the future.

I'll take you through an example of the gameplay how it would be played out at my table.

Let us take an example of a Sherman Firefly [See the attached PDF, Page 193 to 195, as of this update] armed with the QF-17 Quick Firing 17-Pounder Gun [See the attached PDF, page 145 as of this update], firing the Mark 8 Armour-Piercing Capped, Ballistic Capped shell [See the attached PDF, Page 146] against a Panzer IV Ausf G [See the attached PDF, Page 195]. We are going to say that the Panzer IV and Firefly are facing each other dead-on, at a distance of 1341m.

Edited to add: To my knowledge the Mk. 8 APCBC shell did not have a bursting charge.

Example: an untargeted attack

On the Firefly's turn, assuming the gun is loaded and the turret is on target, the gunner elects that he will shoot at the Panzer IV. When the GM asks "Which location?" the gunner elects to shoot at the hull, since the hull is a size 16 target, and at that range Acc and TDD penalties don't apply to size 16 targets, but because the turret is a size 5 target, Acc and TDD penalties at that range would apply. One turn is taken to position the gun onto the target, after which the gunner may aim to acquire bonuses. We'll say that he aims for three turns, collects whatever modifiers he wants, and fires with an attack pool of 8 dice, and gets 7, 6, 3, 9, 8, 1, 3, 4, for a total of two successes.

The Mark 8 APCBC shell does 1d10+14 AP13 damage, versus the Panzer IV's front glacis of 80mm, which is Durability 17. However, DDO of -8 applies, which reduces the damage to 1d10+14 AP5. The player rolls and gets an 8, which comes out to 22AP5 damage, versus the Panzer IV's front glacis of Durability 17, which has been amended to 12 due to the AP value. From there, this means that 12 damage, plus 2 successes are taken out on the Panzer IV's hull, reducing it from Structure 29 to Structure 15.

Now, because the shell penetrated, but it wasn't targeted to someone in particular, we can assume that it manages to miraculously navigate its way through the cramped interior of the tank, and possibly comes to a stop. However, the danger is not yet done. Because the QF-17 pounder counted for 22 during that turn, what we do is we use the spalling formula on Page 134: this is done by dividing the damage by 4 to determine number of dice for a lethal attack, with a radius equal to a tenth of the weapon's damage, or 2 metres for ground zero, 4 metres for the primary blast radius, and 8 metres for the secondary blast radius. (Please note that in the past, I used to use "primary, secondary, tertiary" before I got Warzone, some areas in the PDF still use this)

The area within the Panzer IV is small and cramped, and it's safe to say that everything in the hull and turret would be within 2m of where the Mk. 8 APCBC shell struck. As 22/4 discarding all fractions works out to 5, this means that everyone and everything inside the tank is going to get 5 attack dice rolled against them, with damage being lethal. So we roll five attack dice against all the components inside the tank, this includes the driver, the bow gunner, the commander, the loader, and the gunner, the engine, the ammunition in the hull, the fuel tanks, and the gun breech (which is also used to represent the turret ring and gun elevation mechanism).

The rules for spalling are similar, but distinct from the rules for explosions: I do not use Hurt Locker's "Ground Zero" rule for them at this moment, but I could rework it for that if need be.

The GM rolls five dice on each one. By the end of the turn, the Panzer IV has lost 14 points of structure from its hull (twelve damage inflicted, plus two successes), and the driver walks away with 3 lethal damage, the bow gunner with 4, the commander with 2, the gunner with 1, the ammunition takes 3 damage, which reduces to 2, the engine takes 3 damage which reduces to 0, and the fuel tanks take 2 damage, which reduces to 1. However, the fuel tanks have been damaged. The GM rolls one die, representing one die for each point of structure lost on the fuel tanks to a weapon with incendiary properties (such as a HEI or API round, or in this case the red hot fragments of shell and armour plate that just splintered away) to see if any of them cause it to ignite, and gets no successes. The tracks, gun breech, and the turret are undamaged, but the damage was primarily resolved on the hull -- this is where the successes are contributed to.

In this example, the crew are heavily damaged and bleeding, but they're still alive and the tank can still fight, even after being hit by an AP round.

Example: an attack targeted to the fuel tank

A more interesting approach is a targeted approach. This would be used if the Sherman's gunner elected to use a targeted attack on one of the modules, typically an ammunition rack or a fuel tank.

Let's take the same setup, but this time we'll assume that the Sherman's gunner had deliberately aimed for the ammunition rack, which incurs a -5 penalty for shooting at an unseen target, but as the fuel tanks are size 8, so there's no penalty for Accuracy and TDD.

But rather than the shell being rationalised to have punched through the armour and wind its way through the interior, missing the critical components, and then exit after sending a cloud of razor-sharp fragments all through the tank, instead, the 2 successes from his roll would contribute (almost superfluous) damage to the fuel tank rather than the tank's turret, after making it through the armour and the fuel tank's durability stat of 1. Because the armour of the front is 17, and the fuel tank's Durability is 1, but a roll of 1d10+14 AP13 less DDO of -5 came out to 22AP5 damage, it would inflict a total of 9 damage on the fuel tank after durability and armour.

Should any of the components such as the fuel tanks or the ammunition rack on the tank be destroyed, they do what would be natural after being struck by a red hot shell that just passed through 3" thick armour plating, becoming hot enough to glow in the process. In this case, it's to the fuel tank. The fuel tank explodes into flames, creating the inferno tilt instantly at full intensity. Damage is resolved on the crew and internal components injuring them as per the previous example, with five damage dice rolled against each one individually.

More importantly however, the fuel tank has been destroyed, spilling four hundred litres of gasoline into a white hot solid shell. This immediately starts a fire that burns with the intensity of a gasoline fire (+2), and is the size of an inferno (+3), inflicting five lethal damage per turn. This stacks with the damage that the crew received from the initial spall. The first turn, the ammunition in the rack, which is size 6, durability 1, structure 7, loses 4 points of structure, and if it received 1 damage during the spall, it's now down to 2 structure points left.

The ammunition reaches 0 structure the next turn and explodes. I generally resolve this as resolving one hit from the tank's own weaponry against anyone and anything inside the tank when it blew. When it comes to an ammunition explosion, I might embellish this a little bit by saying the tank's turret would be blasted a hundred feet in the air, and rolling 1d8 (for north, northeast, east, etc) and 1d10 for the number of metres to determine where the turret lands.

Some closing thoughts on those examples...

Because damage to modules is tracked individually, generally it depends on what gets hit, how it gets hit, and any cascading failures, such as a gas tank or an engine or ammunition rack being destroyed, or a crewmember being killed. Most of the time when I've played this with my playtesters, what tends to happen is that the tanks get "knocked out" by all the crew in them getting killed, or their ammunition or fuel tanks being struck and exploding, then taking the tank with them.

It is a bit of a strange system to wrap one's head around, but the idea is to capture the effect of tanks being vulnerable to their own stores of fuel and ammunition. It's more complex, but allows for more nuance and allows for tank combat to last a little longer.

It's my hope that this system of resolving damage individually on each target allows for more depth, since I was thinking that each crewmember potentially could be a player character or an NPC, rather than a nameless stat on a wargame roster, and it would be good to model them and their stations individually.

Please let me know what you think.

Edited to add: I've also included some examples of tank-on-tank combat in Chapter 8, Section 3, Subsection 1: "Tank Examples of Play" which as of this update is on Page 185, showing an exchange of fire between Soviet T-10M and a US M103A2. This includes the use of HEAT rounds and how they work, and how explosive rounds work when they punch through the tank's armour.

I haven't quite gotten to HESH rounds yet, I'll have to add those soon. HE rounds I treat as just using the blast and force. The HE rounds don't do a very good job of punching through armour, but just like real life the big danger is if they hit the roof or the belly plate of the the hull, or the turret roof. If the damage exceeds the roof's durability, excess damage is carried over into the crew stations underneath it. This can lead to situations like a round striking the turret face and being absorbed by the frontal turret armour, but the driver, being located under a thin hull roof, not being so lucky.

Further Edited to Add: I just realised I have made a small mistake on the tank examples of play. The M103A2's 120mm Gun M58's M358 APCBC-T shot should not have a bursting charge, as it is a solid shot but is mistakenly played in the examples of play as having a bursting charge. I will fix this in a future update.

**Jester-PFG** · 12-13-2022, 10:18 AM

I decided to provide a small preview to what I provide here, on this forum, to save you guys a bit of searching through a 200+ page document to find a single entry.

Once again, I know this doesn't look like anything you've probably seen in Chronicles of Darkness, because I've added so many extra features to the game on top of this. However, these optional add-on rules are compatible with Chronicles of Darkness and are scaled to the same relative baseline as I've outlined in the second post. The rules for Terrain Rating, Turret Traverse Speed, Gun Stabilisation, Tactical Diameter, and other detailed mechanics that aren't in the core rulebook or armoury are there to make the tanks handle more realistically; these rules are under Vehicle Rules in the document linked in the first post under "Permalink."

This is an entry for the T-72A, and I've included the T-72B and T-72B3 obr.2016 as variants, representing different variants of the T-72 from history at 1976, 1988, and 2016, respectively. The T-72B is intended to be the Soviet counterpart to the M60A3(TTS) I've already added to the PDF. Both the T-72B and M60A3(TTS) are intended to be opponents and represent both sides of the Cold War, and are still in use by several countries around the world to this day. The Russian Ground Forces still rely heavily on the T-72B3, as the T-90M and T-90 had a lower production run.

The 2A46 smoothbore 125mm gun and its ammunition types are under "Modern Breech Loading Cannons" in "Tactical and Heavy Weaponry", as of this update, on Page 156. I don't have separate entries for the PKT and the NSV machine guns, but at this moment the M60 Machine Gun (which has the PKM, which is a dismounted version of the PKT listed under "Comparable Weapons") can be used as a stand-in, same with the M2HB-QCB Browning Machine Gun, as the differences between 12.7x99mm NATO and 12.7x108mm Soviet aren't great enough to merit an entirely new statblock except for vanity/history.

The T-72A's gun stabiliser was only effective to around ~25km/h on relatively level ground [T-72 Main Battle Tank 1974-93, Steven J. Zaloga], and the combustible-cased ammunition in the T-72A is entirely unprotected within its autoloader, which in turn is housed unprotected in the crew compartment. Both these aspects have been mirrored here by reducing the Gun Stabilisation to only -4, and the Durability of the ammunition hold to 0.

I will add this to the next update and correct the existing T-90/T-90M entry to update to the newer information.

Playable Game Content

T-72A - Basic Stats
Curb Weight: 41,000kg
Powerplant: V-46-6 V-12 Diesel with H24 Supercharger, 780 hp (580kW)
Maximum Speed: 60km/h (50 metres per turn)
Acceleration: 4 metres per turn, per turn
Handling: -3
Terrain Rating: 4(Max)/ 5(Half)/ 6(Quarter)
Tactical Diameter: Neutral
TTS: 2/1
Gun Stabilisation: -4
Crew: 3: Commander, Driver, Gunner
Fuel Capacity: 705L internally, +2×275L external tanks
Range: 600km (est)
Armament:
1× 2A46-1 125mm Smoothbore Gun, 44 rounds
1× PKT 7.62×54mmR Machine Gun, Coaxial, 2000 rounds
1× 12.7×108mm NSV Machine Gun, Commander's Hatch, 300 rounds

T-72A - Durability and Structure
Turret: Size: 6, Structure: 75
Front (Composite, 450mm RHAe): Durability 69
Sides (240mm, sculpted): Durability 42
Rear (40mm): Durability 12
Roof (40mm): Durability 12
Hull: Size: 12, Structure: 52
Glacis (60mm, sloped 68°) Durability: 15 (normal), 40 (line of sight)
Sides (80mm): Durability 18
Rear (40mm): Durability 12
Roof over engine deck (20mm): Durability 9
Tracks: Size 7, Durability 9, Structure 16
Systems
Engine (in hull): Size 7, Durability 3, Structure 10
Ammunition Hold (hull and turret): Size 6, Durability 0, Structure 6
Fuel Tanks (in hull), Size 10, Durability 1, Structure 11
Gun Breech (in turret), Size 5, Durability 10, Structure 15
Autoloader (turret component), Size 3, Durability 1, Structure 4
Autoloader (hull component), Size 3, Durability 1, Structure 4

Development for the T-72 dates back as far as 1965, with the acceptance of the T-64, developed under the codename of Objekt 432, into the Soviet military. However, while the T-64 looked good "on paper" it made use of many new technologies all at the same time, such as an all new suspension and an autoloader which were costly to produce and sometimes prone to reliability issues, and only two years later, VPK, the Military Industrial Comission of the USSR aimed to replace the T-64 with something that they hoped would cut the cost of the T-64 by half, designated Objekt 172 and codenamed the "Ural" which eventually would become the T-72. In keeping with the USSR's philosophy of keeping the tanks as small and as light as possible to minimize weight, maximize protection, and reduce target silhouette, the T-72 weighs about 41 tonnes.

By 1968, the first prototype for Objekt 172 was completed. Objekt 172 featured suspension based off the older T-62 for reduced cost and greater reliability. By 1972, the design was completed and production began, which was quickly accepted for Soviet use. Although initially the design was intended only for use within the Soviet Union, by 1976, the Soviet government made the decision to license production of the T-72 to allied countries, including Poland and Czechoslovakia, which produced their own versions.

The T-72 is so numerous and in service in so many locations, it has a huge number of variants, but at the heart of each T-72 is the 125mm smoothbore 2A46-1 gun mated to a 2Eh28M two-axis stabiliser and a 44-round carousel mounted in the hull. Loading is accomplished by lowering or lifting the gun barrel to 3° of elevation, allowing the carousel to rotate the cassette containing the projectile and propellant to the loading position, elevate, and be rammed by the autoloader. Once loaded, the gun may return to its previous position. Although it is possible for the autoloader to complete the loading cycle in as little as eight seconds, the carousel only turns in one direction: therefore, it can take as many as fifteen seconds if the next round is in a bad position, which will require the carousel to traverse through its entire magazine before finding the requested round.

While the autoloader is held to be reliable, if the tank's hydraulic power to it is lost or disabled, the autoloader can be cranked by hand to supply power. However, this is a very slow process, and the gunner cannot access the rounds and feed them by hand: manual loading may be done by the tank commander turning a pair of cranks to force the machinery to move. This process takes 22 turns, minus the commander's Stamina dots.

Although legends persist of the T-72's autoloader "chopping off the gunner's arm and stuffing it into the breech", this is a myth. The T-72's autoloader consists of a cassette and rammer rather than a "mechanical arm" as these legends sometimes suggest. While the moving machinery is unprotected and presents numerous dangerous pinch points which can definitely remove a limb if one were to be inserted into the machinery, this is typical for all tanks, rather than being exclusive to Soviet ones. To actually load a crewmember's arm into the breech would require the gunner or commander to reach over over the autoloader, into the path of the dangerous machinery before pushing the button. Nevertheless, the interior of the T-72 is extremely cramped and uncomfortable, which contributes to crew fatigue.

The gunner has access to an 1A40 gunsight complex and fire control system and TPNZ-49 night sight, which automatically measures the lead angle of a target, and the commander has a K10T collimator sight which includes a roof-mounted infrared sight. A searchlight is mounted on the front of the turret, on the right side of the gun (from the commander's perspective) which can double as both an infrared search light and a visible light search light through the use of a filter.

The hull of the T-72 is built from rolled homogenous steel armour and made by welding, and the distinctive dome-shaped turret is produced by casting. On the T-72A, there is a combination of fiberglass or silica plates set behind the front glacis and near the front of the turret, intended to act as an early composite armour.

In the west, the T-72A has the reporting name of "Dolly Parton."

The T-72 would compete with the T-64 and the later model T-80 as the main battle tank of the Soviet Union, and later with the newer T-90s. Despite the huge variety of tanks that the Soviet Union and its successor states, namely Russia procured, the T-72 ended up being being produced well into the late 1990's, and modernized versions, the T-72B3 obr.2016 started being delivered to the Russian Ground Forces in 2017. According to Jane's Information Group in 2019, the T-72 is likely to remain in service indefinitely; even wealthier countries that use the T-72 or any of its variants are likely to keep them in service for generations to come.

Variants

T-72B

The T-72B or "Super Dolly Parton" is an improved modification of the T-72 which entered service in 1988 after being introduced in 1985. The main difference between the T-72B and T-72A is the addition of Kontakt-1 explosive reactive armour bricks attached to every surface possible over the tank. The T-72B gains ERA armour that provides an additional 400mmRHAe protection against HEAT, HESH, and HE shells, for an additional +61 of armour, with the usual rules of ERA applying. However, the Kontakt-1 explosive reactive armour bricks are useless against kinetic shells: this durability is reduced to zero versus kinetic shells. Replace the engine with V-84M V-12, generating 840 horsepower, and increase the curb weight to 44,500kg.

Unlike its predecessor, the T-72B has the equipment necessary to fire guided missiles from its main gun.

T-72B3 obr.2016

Following a prolonged period of financial problems that reached a boiling point at the end of the 1990's, the Russian Ministry of Defence could no longer afford to purchase T-90s, which resulted in the Ministry of Defence opting to instead upgrade some of its reserve T-72BM tanks that had been mothballed since the dissolution of the USSR. The upgrade started in 2011, and by 2016, the first units were issued to the Russian Ground Forces. Since then, the T-72B3 obr.2016 has become the most numerous and upgraded T-72 version in the Russian Ground Forces.

The T-72B3, and its successor, the T-72B3 obr.2016 removes the search light and the Kontakt-1 explosive reactive armour bricks, and replaces them with the Kontakt-5 "wedges" around the circumference of the turret which provides an additional +61 ERA Durability to the turret front, sides, the hull sides and front glacis, applying equally to explosive rounds, and half to kinetic rounds, with all the usual limitations of single-use ERA bricks. The searchlight was deemed unnecessary and eliminated to make room for the Kontakt-5 modules.

Replace the gun with the 2A46-5, allowing the T-72B3 to fire the same ammunition as the T-90, mirroring its Gun Stability Rating to allow it to fire on the move. The T-72B3 obr.2016 is outfitted with the 3EC13-1 fire extinguishing system and has the V-92SF diesel engine, which increases output 1,130hp (850kW). Increase curb weight to 46,000kg.

Special Rules

Poor Reversing: Many Soviet and Russian tanks do not have more than one reverse gear, and have a very slow reversing speed. Tanks with this rule are limited to 1/10th of their overall speed when driving in reverse.

Autoloader: The T-72 relies on the use of an electrically driven autoloader for its main weapon. This move eliminates the loader's station. Rounds are stored centrally underneath the turret basket, in the hull of the vehicle, where the machine selects them, elevates them up into the gun breech, then positions and loads them. The autoloader extracts the stub from the gun breech and tosses it out of a small hatch in the back of the turret so the process can be restarted. Although both Eastern and Western philosophy disagrees on the use of autoloaders, the use of tank autoloaders automates the process of reloading the main gun and saves considerable amounts of space compared to a human loader.

It takes 3 turns for an autoloader to finish its cycle. If initiative for the autoloader must be determined, assume that the autoloader functions at the height of the initiative order. Once a round has been loaded by the autoloader, the machine cannot take it back out and stow the round, it must be either fired or ejected.

Both components of the autoloader must be in functioning order for it to work. Should either the autoloader components in the turret or hull be reduced to 0 structure, the autoloader is destroyed and the main gun cannot be used.

Poor Gun Depression: Soviet doctrine held that tanks would be fighting in big, wide open spaces, and that tanks would be handling offensives while charging forward on the move, rather than fighting defensively while taking cover behind a hill. As a result, Soviet analysts deemed that trading a large turret which would have allowed for more gun depression for a smaller turret which offered a lower profile for less target presence and less weight would be a net gain.

This has the effect of making the turret smaller and more compact, which was advantageous during the Cold War, prior to the days of computer-assisted aiming. However, the lower turret meant that the large and bulky gun breech would have no space to travel opposite the barrel. Tanks with this rule have an extremely limited arc that they may lower their gun barrel through. This seriously hinders the tank's ability to fight from a defensive position or in defilade.

Vehicles with this rule cannot fight effectively from a hull-down position. When going hull-down in any position that was not purposely set up for the tank such as a concrete barrier sized appropriately to the height of the tank's turret ring, the tank's main weapon suffers a -5 penalty to hit. This stacks with any other modifiers and may exceed the -5 maximum.

Modifications

Improvised Roof Armour: During the 2022 Invasion of Ukraine, some Russian tanks were seen with what appeared to be slat armour bolted onto the top of the tank. Many of them appeared to have been improvised and made from structural steel or corrugated metal or even sections of chain link fence. These were nicknamed kozyrek ot solntsa or “sun visors”, but detractors on the internet mocked them as “cope cages” following some reports of the improvised armour being ineffective at increasing protection of the tank’s roof versus HEAT rounds and Javelin antitank guided missiles.

Mechanics: A centimetre or roughly a half inch of structural steel armour spaced approximately a metre from the tank, if done correctly and under ideal circumstances, has the potential to add up to Durability 4 (Spaced) over the tank’s roof. The GM secretly rolls the maker’s Intelligence + Crafts skill, which suffers a -3 penalty if the designer does not have any specialty in modern armour design, antitank weaponry, or similar. Successes, to a maximum of 4 decide how much armour with the Spaced modifier is gained. On a failure, no benefit is gained but the drawbacks still apply. The amendment for non-ballistic grade steel is factored into these numbers. Penalties apply for inadequate materials. The use of these improvised armour cages preclude the use of the remote weapon stations, and limit any weapons mounted on the commander’s hatch to being able to fire only directly forward and at ground level. Lastly, they increase the amount of time taken to enter or exit the vehicle by an extra turn for any of the turret crew.

Information, fluff and special rules for the 2A46 family of 125mm Smoothbore Guns is included in the PDF. This ammunition selection applies to the T-72A, which lacked the capability to fire guided missiles from its gun. It's been posted here for a preview, as well as the 3OF26 HE round.

The 3VBM9 APFSDS-T will do 32 AP30 damage on an average roll of 1d10. This is by design: it simply means that given our baseline given by the armour chart in the section "Vehicle Armour", around half of the time, the sabot will penetrate a solid wall of high strength, hardened steel approximately 170mm or just shy of 7" thick, inflicting 8 damage dice in spalling when it does on anyone within a radius of 3m, 4 damage dice on anyone within an arc of 6m, and 2 damage dice for anyone within 12m. If you play without the rule for enhanced lateral effects, it will on average inflict an average of 3 Lethal Damage on everyone three metres on the other side of penetration when it does. If you play with the rule for enhanced lateral effects on a tank sabot (immediately count half the spall dice as successes, add inferno rule for affected blast area) it will do an average of 5 Lethal Damage, 3 Lethal Damage, and 1 Lethal Damage respectively in the same arcs as well as cause the Inferno tilt, which can then set fire to and cause the fuel and ammunition stored in the target vehicle struck by the sabot to explode. Spalling Damage is limited by the Durability of the object struck: firing the 3VBM9 APFSDS round at the windshield of a humble passenger car, which will likely have nothing more than a thin sheet of tempered glass protecting the passengers rated Durability 1, will simply result in the round passing through the car by going in one side and out the other without any lateral effects, provided the penetrator doesn't actually hit any of the passengers on the way through.

32 AP30 damage may sound like an insane amount considering the most powerful weapon in Chronicles of Darkness Core Rulebook is the Chainsaw at 5L 9-again AP0, but bear in mind, we are talking about a tank gun from the Cold War: a .44 Magnum, which is suggested as a 2-Damage "Heavy Revolver" [Chronicles of Darkness, Core Rulebook, P.268] firing a 240-grain jacketed hard cast lead bullet at close to 1,300 feet per second won't even put one dent in a 10mm thick AR-500 hardened steel plate ("Abrasion Resistant" steel, commonly used to line the inside of dump trucks or earth movers) at half that distance. Modern tank guns must sometimes penetrate combinations of high-strength hardened steel plates, ceramic, voids, and ultra-hard materials like tungsten or depleted uranium that work in concert with each other to add up to the equivalence of a metre of hardened high-strength steel plate, from two kilometres away! Everything is relative.

I understand that an APFSDS round that hits tank armour will typically break itself and the armour plates they hit into at least a bucket-sized amount of buckshot-sized pellets going at multiple kilometres per second, each of which will be glowing hot from the friction of entry. However, I deliberately chose to make spalling a tiny bit weaker than it would have normally been suggested to to allow for crews to have some odds of surviving a direct penetrating hit to their tank grievously wounded but alive. This was one of the rare times I decided to allow gameplay and conservation of drama to supercede a gameplay choice, but it was deliberate on my part.

2A46-1 125mm L/48 Smoothbore Gun (1976)

Damage: 1d10+26 AP* (dependent on shell choice)
Calibre: 125×383mm (Two part)
Range: PB/1250/2500/5000
Accuracy: 5/7/10/15
TDD: 1/1/1/2
Reload: 3 Turns (Autoloader)
Crew: 1

3BK12M HEAT-FS: High Explosive Anti-Tank, Fin-Stabilised
Damage: -7 +AP46
Force: 6+6d AP4 (not cumulative with Damage)
Blast: 15/30/60
DDO: 0/0/0/0

3OF26 HE: High Explosive
Force: 6+6d AP4
Blast: 20/40/80
DDO: 0/0/0/0

3VBM7 APFSDS-T: Armour-Piercing Fin-Stabilised Discarding Sabot, Tracer
The 3VBM7 changed the performance of earlier high-strength maraging steel penetrators slightly by adding a longer and slightly heavier projectile to improve performance, and was issued in 1972.
Damage: +AP23
DDO: 0/0/-2/-4

3VBM9 APFSDS-T: Armour-Piercing Fin-Stabilised Discarding Sabot, Tracer
In 1976, the penetrator of the 3VBM7 APFSDS-T was completely redesigned, with a steel-encased tungsten carbide penetrator and redesigned geometry. Entered service in 1976.
Damage: +AP30
DDO: 0/0/-2/-4

**Iguazu** · 12-17-2022, 09:33 PM

You're very detail-oriented and technical.

**Jester-PFG** · 12-18-2022, 03:25 AM

Thanks, I hope that this might be useful someday.

I'm going to shift gears and work on a different area besides tanks for next update. I work on this as time permits, but I should have more content once things settle down in the new year.

**Jester-PFG** · 01-29-2023, 03:14 PM

Hope everybody had a great holiday!

As of this update, in Chapter 5.5: Light Machine Guns, I've added mechanics for The Beaten Zone, as well as searching and traversing fire, which is applicable for use with machine guns with traverse and elevation mechanisms, as well as mechanics for grazing fire. This adds an extra dimenison for machine guns in game which very few games capture. For more details, I've included a link to a Marine Corps Tactical Publication on machine guns and machine gunnery which should help to explain what The Beaten Zone, Searching and Traversing Fire, and Grazing Fire is in the footnotes of this post [1].

I owe a deep debt of gratitude to one of my subject-matter experts for explaining to me that machine guns have considerably greater tactical applications than may initially meet the eye, and machine gunnery is to itself a considerable science, more akin to artillery. These rules are at this moment untested, so I'll be playtesting them later and making edits and adjustments as necessary.

Chapter 7.1.3 as of the time of writing now features a small chapter on strategic-level warfare. I got the idea after exploring ICBM by Matrix Games[2], and decided I could use that in my table, since my table has routinely discussed the implications of a nuclear weapon in use. I developed a number of (extremely simplified) procedures for simulating the process of nuclear warfare at an RPG table and the "fog of war" inherent to the situation, which involve writing your plans onto notes which get placed in the center of the table, and then the notes being read off once everyone's committed. This is intended to capture the game theory involved with a first strike and launch-on-warning capabilities, as well as the value of survivable second-strike capabilities.

Currently, I only have mechanics for the Trident II and the Minuteman III in service with the United States' Navy and Air Force respectively, but I may add the RS-24 Yars, which is intended to replace the RT-2PMP Topol-M, as well as the R-36 ICBM, and R-56 Bulava and R-29 Vyosota at a later date. In the future I intend to add the Titan and the LGM-118A Peacekeeper, for the "what if" crowd. However, I'm planning to spin off all of the air and naval warfare stuff into a separate book, since any RPG supplement longer than 200 pages starts to get a little bit cumbersome and I haven't even gotten onto IFVs at this stage. I've included some rudimentary figures for some other nuclear weapons in the USN's and USAF's stockpile, which I've obtained from Stardestroyer.net's nuclear weapons effects calculator[4]. Currently, I haven't included any ballistic missile defence systems (such as the Aegis Ballistic Missile Defence System) into the book, but I could at a later date. I'm somewhat hesitant to go that route because actual data on ballistic missile defence systems is somewhat scarce and I would have to do a lot of guessing to get them represented.

As always, any comments, questions and feedback that could help me produce a better supplement are welcomed.

[1] Marine Corps Tactical Publication (MCTP) 3-01C, Machine Guns and Machine Gun Gunnery. - 1-12 (Page 22 of the PDF at this time) - https://www.marines.mil/News/Publica...23/mctp-3-01c/

[2] "ICBM" - Matrix Games: https://www.matrixgames.com/game/icbm

[3] NUKEMAP by Alex Wellerstein - https://nuclearsecrecy.com/nukemap/

[4] Star Wars vs Star Trek: Nuclear Weapon Effects Calcuator by Michael Wong - http://www.stardestroyer.net/Empire/Science/Nuke.html

**Iguazu** · 03-03-2023, 09:42 PM

Have you ever seen the movie, White Tiger? Inspirational.

**Jester-PFG** · 03-17-2023, 11:41 PM

Originally posted by Iguazu View Post

Have you ever seen the movie, White Tiger? Inspirational.

Absolutely! I've actually listed it on (at the time of posting) Page 14 of the PDF, under "Inspirational Sources." It's not only got tank action, but it also aligns with how I would want to portray the supernatural alongside tanks and war when GM'ing for Chronicles of Darkness. The way in particular that it portrayed Naydenov in particular was huge for me and I think that's what I would want to aim for in terms of feel and aesthetic to the campaign.

White Tiger was actually one of the sources of inspiration for Gods of Iron and one of the reasons I decided to include some Second World War era stuff. If you're curious, I have the Tiger Ausf B. Konigstiger (the "King Tiger" or Tiger II, or rather, the Tiger I's eventual successor) in Gods of Iron. I don't have the T-34-85 or the Tiger I yet, but I could add those later. At the time of posting, the King Tiger is on Page 203 of Gods of Iron, under "Second World War Heavy Tanks"; I included it and the Sherman because at the time I had been doing some reading on The Battle of the Bulge.

Things have been a bit slow because I haven't had as much free time as I had before, but I've recently been considering moving the sections on stuff for naval and air operations into their own books, which I want to call Seas of Steel and Angels and Aces respectively and focus on those at a later point in time, since I feel like I should try to avoid splitting my focus and the book's already more than 200 pages long.

**Jester-PFG** · 04-22-2023, 06:35 PM

I know it's been a while since I updated this, but this weekend I was able to scrape together a small update. I promised combined arms warfare, so I'm working on delivering some of that rather than just straight-up tanks, so we can have some more diverse options in gameplay.

I just updated the document today and added the M3 Bradley.

I've added a section on IFVs, and I decided to add the M3 Bradley and all of its weapons. Unlike the other additions that I used here, the numbers for the M242 Bushmaster and the BGM-71E should be more or less good, rather than placeholder values.

Even if combined arms warfare isn't in your Chronicles' focus, I think that more player groups and GMs will find more use for IFVs rather than tanks, so I decided to focus on that and add this. I now have stats for the M3A4 Bradley (which can be worked backwards to get stats for the older M2 Bradley) represented in Chronicles of Darkness.

Hope you like it, I've posted the excerpt below.

M3A4 Bradley
Curb Weight: 27,600 kg
Powerplant: Cummins VTA-903T Turbodiesel (675 bhp, 500kW)
Maximum Speed: 65km/h (54 metres per turn)
Acceleration: 6 metres per turn, per turn
Handling: -2
Terrain Rating: 5 (max)/ 6 (half)/ 8 (quarter)
Tactical Diameter: Neutral, 0+(speed+1)/2
TTS: 1/1
Gun Stabilisation: -10
Crew: 3: Commander, Driver, Gunner + 2 Passengers
Fuel Capacity: 660L
Range: 500km (est) on road
Armament: 1× 25mm M242 Chain Gun (900 rounds), 2× BGM-71E TOW-2 anti-tank missile tubes (12 rounds total), 1× 7.62×51mm M240C Machine Gun (2,200 rounds)

The M2 Bradley Infantry Fighting Vehicle entered service in December 1981 as a replacement for the US Army's M113 Track which was starting to overstay its welcome along with the M60 Patton. Designed without weapons and with a much older powerplant and transmission, the M113 Track could keep pace with the M60 Patton it was designed to accompany into battle, but not with the newer M1 Abrams MBT that was replacing the Army's faithful go-to. After a long and slightly troubled development history, the Army selected a design tabled by United Defense and named it after General Omar Bradley.

United Defense took a new approach to designing the M2 Bradley, and built it resembling a small tank of sorts, with a 25mm chain gun as its main weapon, with hardpoints to accomodate other weapons, including TOW missiles, and rounding out the main gun with an M240G mounted machine gun. Additional ports for firing port weapons allowed the passengers to add to the Bradley's arsenal, although these were found to paradoxically \textit{decrease} survivability and were eliminated on later versions.

The M2 Bradley was one of the first vehicles to use aluminium in its armour. This was a move that came with considerable controversy; although the armour was capable of standing up to the 14.5mm armour piercing rounds that the Soviet BMP fired, the armour was also liable to burn at high temperatures, which was blamed on some of the casualties that the Bradley sustained. Nevertheless, the Bradley proved to be considerably more survivable than wheeled LAV (Light Armoured Vehicle).

In response to complaints about insufficient survivability, subsequent versions of the M2 Bradley did come with hardened steel side skirts and armour which increased the weight of the platform, and required the engine to be upgraded to produce 600 horsepower to maintain the Bradley's desired speed and performance. This became the M3 Bradley, which is depicted here.

The M2 Bradley would later gain fame in the Gulf War, especially during the Battle of 73 Easting, the largest tank battle since the Second World War, in the coalition response to the Iraqi invasion of Kuwait. Bradleys used their TOW missiles to engage the Iraqi Republican Guard T-72s, and scored more kills on Iraqi T-72s than the M1A2 Abrams did.

Although the Bradley has been arguably a successful design, it has not been without considerable amounts of controversy; the cramped interior has been cited in reducing the effectiveness of the crew and the passengers, and some have called the M2 Bradley "a jack of all trades but a master of none" citing the limited number of TOW missiles it can carry, as well as the IFV's great weight and relative lack of survivability. Efforts have been underway to replace the M2 Bradley since the late 1980's, although so far only in the late 2010s were serious efforts finally made to replace it with the Next Generation Combat Vehicle. The M3 Bradley was meant to address a number of these shortcomings, although it did so by giving up room for passengers as well as its ability to mount a floatation curtain for deep fording.

The M2A3 replaced some of the Bradley's analogue optics and analogue fire control system with an all-digital fire control and weapons system, which continues to see service on the newer M3 Bradleys. It's very likely that the Bradley, while its replacement has been talked about for over forty years, will continue to serve in the US Armed Forces (as well as a number of other militaries that the M2 Bradley has been exported to) for the foreseeable future. The Bradley will likely be exported to Ukraine as part of foreign aid to assist Ukraine in the Russo-Ukrainian war.

Armour and Systems

Size / Durability / Structure

Turret
Front (Aluminium, 50mm RHAe) (7 / 13 Cp / 20)
Sides (Aluminium, 50mm RHAe) (- / 13 Cp / -)
Rear (Aluminium, 50mm RHAe) (- / 13 Cp / -)
Roof (Aluminium, 30mm RHAe) (- / 10 / -)

Hull
Glacis (Aluminium, 50mm RHAe) (16 / 13 Cp / 29)
Sides (Aluminium, 50mm RHAe) (- / 13 Cp / -)
Rear (Aluminium, 50mm RHAe) (- / 13 Cp / -)
Belly (Aluminium, 50mm, RHAe) (- / 13 Cp / -)
Roof over engine deck (30mm RHAe) (- / 13 Cp / -)
Tracks (7 / 10 / 17)

Systems
Engine (in hull) (7 / 3 / 10)
Ammunition Hold (all rounds in hull) (5 / 1 / 6)
Fuel Tanks (in hull) (5 / 1 / 6)
Gun Breech (in turret) (5 / 3 / 8)

Variants

M2 Bradley

The original M2 Bradley carried more room for passengers (although by no stretch of the imagination in comfort) as well as carried room for firing ports (see below).

Mechanics: Eliminate all but 2 of the TOW missiles, and increase passenger space to accomodate up to 6 passengers. Reduce armour to 40mm RHAe, or Durability 12.

M6 Linebacker

In the late 2010's, studies were done to see if the Bradley chassis could be converted to a short-range air defence platform citing the emergence of drones and smaller airborne threats.

[b]Mechanics:} Replace the 25mm Autocannon and the M240C machine gun with an XM914 30mm Autocannon firing self-destroying rounds. Remove the TOW missiles and replace them with either the FIM-92 Stinger or the AIM-9X Sidewinder missile. The vehicle gains the "Anti-Air" rule for these weapons but the FIM-92 and the AIM-9X sidewinder cannot be used to target ground targets.

Special Rules

Firing Ports

Only available on the M2 Bradley

The M2 Bradley originally was designed with a number of ball mounted ports and vision blocks from which the crew could use to fire from the sides and rear door of the vehicle with specially equipped carbines cut down to work as firing port weapons, following some experimental tests and data gathered from experiences in the Vietnam War.

The M2 Bradley's Firing Port weapons may be fired to the side facings or out the rear door only and must be operated by the passengers. A -1 penalty is observed when using them and a minimum range of 3m applies, below which is an automatic chance roll. The M231 Bradley Firing Port Weapon resembles a small, open-bolt M4 Carbine with a mounting interface in place of the handguards. Due to the lack of sights, the operating procedure for the FPW was to point the gun in the direction of the target and walk a spray of bullets onto it while viewing the spray through a cramped periscope on the roof, and the gun's painfully high rate of fire thanks to a series of modifications which included replacement of the fire control group with an open-bolt fire control group and small magazine size made this difficult. The FPW can only fire medium and long bursts and always counts as firing from the hip; the ball turret precludes the use of sights.

Although they looked good "on paper" experiences in combat quickly showed that these firing port weapons proved to be less than ideal on a two-way range when missiles and rockets entered the fray. Troops often paradoxically survived for longer (allowing them to remain effective in battle for longer) if they could get \textit{out} of their vehicle as quickly as they could and engage enemy forces on foot, rather than try to return fire from the confines of an extremely cooped up and cramped vehicle that carried an enormous target presence for incoming rockets that its armour could not defeat. As a result, most of the M2 Bradleys at the present day have had their firing ports permanently removed and blanked off with metal plates welded overtop to eliminate the weak points in the armour left by the ball turrets. The M3 Bradleys lack firing ports entirely.

The Bradley's firing ports are considered a size 1 weak spot. However, they are only Durability 4, Structure 5, and they can be shot out if directly targeted.

V-Belly
In response to casualty rates resulting from bombs and landmines in Vietnam, the M2 Bradley was outfitted a V-Shaped hull that would try to deflect the blast of an explosive away from the vulnerable belly of the vehicle and out its sides. This increased the chances that the vehicle or the crew would survive if it rolled over a bomb.

Count the vehicle as being 25\% smaller than it normally is (round in favour of the vehicle) when calculating the damage it takes from an explosion from a landmine or an IED.

Smoke Launchers
Each Bradley carries several four-barrelled smoke launchers on the perimeter of the turret which can be fired from the commander's station to lay down cover of smoke to obscure the vehicle on the battlefield.

At any point as a Reflexive Action, the commander may choose to cover the area surrounding the vehicle by deploying the smoke launchers. The area around the vehicle, within a 20m radius counts as being in darkness, even to infrared vision, as the smoke generated by white phosphorous smoke generators is opaque even to infrared light.

US M242 Bushmaster
Damage: 7+3d AP*
Calibre: 25×137mm
Range: PB/1500/3000/6000
Accuracy: PB/5/7/10
TDD: PB/1/1/1
CEP: T
Magazine: Varies
Rate of Fire: 500 rounds/min
Weight: 260lbs.
Special Rules: Autofire

The M242 Bushmaster Chain Cannon was developed by Hughest Helicopters in the 1980's. Development started when it was clear that the old M113 "Track" Armoured Personnel Carriers, while they were good at taxiing soldiers to the battlefield and protecting them from fragments and small arms fire en route to it, could contribute little to the battle beyond having a machine gun or two under some circumstances.

The US Army tabled specifications for a vehicle that would function as the M113 did as an armoured troop carrier that could not only carry troops to the battlefield, but also support them once they got there with a weapon similar to the older 20mm aircraft cannons that saw use during the Second World War. The older M139 Autocannon that had served in this role was unsatisfactory and the Army put out a contract to build a new one.

Hughes Helicopters developed the M242 Bushmaster. Unlike the older M139 Autocannon, the Bushmaster used a powerful electric motor to drive the cannon's mechanism, which consists of a large, sprocketed chain that carries the individual rounds to the breech of the gun and actuates it, and even allow for rounds to be switched between different types on the fly. Hughes designed it to be reliable, simple, and easy to maintain, with the assembly coming apart into separate modular sub-assemblies that can be dismantled and reassembled quickly. In an emergency, the weapon can be hand-cranked to fire, although at a much slower rate; the weapon may only fire short bursts when hand cranked.

The M242 Bushmaster sees use across all branches of the US Armed Forces including the Navy and the Coast Guard as the Mark 38 Autocannon, as well as in the armed forces of Australia, Canadian, and New Zealand, and many other militaries.

M793 Target Practice, Tracer
The M793 Target Practice round contains no explosive filler.
DDO: 0/-1/-2/-4
M791 Armour-Piercing, Tracer
The M791 Armour-Piercing round contains an armour piercing sabot, and is
intended to penetrate light to moderate vehicle armour.
Damage: -2
AP: +12
DDO: 0/-3/-5/-7
M792 High Explosive Incendiary, Tracer
The M792 HEI round carries an explosive charge to increase its damage
potential against lightly armoured targets and enemy infantry.
Damage: +LV
Force: 4+4d AP4
Blast: 2/4/8
DDO: 0/-1/-2/-4
Incendiary. Should the M792 High Explosive Incendiary round deal any damage to flammable materials, accelerants, fuel or ammunition via its blast force, roll a number of dice equal to the damage inflicted. On a success, it ignites.
M919 Armour-Piercing Fin Stabilised Discarding Sabot
The M919 APFSDS lacks a tracer, and instead uses a penetrator made from depleted uranium.
Damage: -2
AP: +15
DDO: 0/-3/-5/-7
As is the case with depleted uranium rounds, the rounds will explode into flames should they strike hard armour plates, and thus carry the incendiary rule.

BGM-71E TOW2
Damage: 1d10+10 AP80
Force: 6+6d
Blast: 5/10/20
Speed: 720km/h (600m per turn)
Range: 100/MR/4000
Accuracy: 15
TDD: 1
CEP: T
Flight Height: Direct-Fired
Weight: 50lbs.
Size: 5

The BGM-71 Tube-launched, Optically-tracked, Wire-guided or "TOW" missile is an anti-tank guided missile that first saw service in the 1970's with the United States Army in the Vietnam War and traces its heritage back to some experimental weapons developed by Nazi Germany which placed wire guidance onto rockets to turn them into tethered missiles, intending them to be fired from bombers.

By the end of the 1950's, the novel concept of using a spool of ultrafine wire to transmit missile guidance commands to a missile had caught on. The MGM-51 Shillelagh Missile, which despite being technically advanced and highly ambitious, had several problems with expense, reliability, and subject to issues with IR interference from flares and countermeasures. The newer weapon was intended to be less expensive and more reliable.

The Ballistics Research Laboratory created the acronym "TOW" and development progressed over the 1960's, and Hughes Helicopters won the contract to produce what became the BGM-71 TOW; this missile would weigh about fifty pounds and to facilitate launch from both helicopters and land based platforms including on vehicles and on tripods, the missile would have small, spring-loaded fins that would extend when it launched. The first missiles carried a 4-kilogram high explosive charge; this was later replaced by a 6-kilogram high explosive antitank warhead which was billed as being capable of punching through 900mm of rolled homogeneous steel armour plate, but subsequent evaluations have placed this to be significantly lower in the realm of 600mm RHAe.

The TOW missile is guided to its target via optics, and the gunner must keep the sights on the target in order to steer the missile toward it until it hits, which means that the missile is not fire-and-forget. For this reason, the dice are rolled only at the moment of impact, and should the gunner move or apply defence while the missile is in flight, roll a chance die; only on a success can the missile hit or be continued to be aimed on a subsequent turn.

In real life, there is a small delay between when the launch command is sent to the missile, and the missile actually launches; the missile must activate its onboard internal battery and guidance system. For this reason, TOW missiles fired at ranges within 600m are resolved last in the turn, after any other weapons and artillery systems have been resolved.

**Jester-PFG** · 07-18-2023, 02:10 AM

Hello again,

Just a heads up that I haven't abandoned this endeavour, I've just been very busy lately. A lot has happened since the last update, I've restructured the entire document, which included spinning off several of the entries and rules into their own LaTeX files for numerous entries (I never want to do a 22-Branch Octopus Merge ever again as long as I live, for as long as I have to) as well as reorganizing the way the document is organized to make it easier to read. I've moved most of the sections on vehicles into their own part, to make things read more coherently.

Someone in another thread had suggested that they were interested in doing siege engines for Chronicles of Darkness and in particular doing Mediaeval siege engines for Genius: The Transgression, so I decided to add some stuff for you this update, it's near the end.

My group expect to start seeing situations involving fortifications, and penetration of reinforced concrete are likely to become a factor, rather than just vehicle armour, so what I've done is I've taken the opportunity to develop penetration tables specifically for the purpose of attacking structures made from reinforced concrete, which can also be used as a guide for brick, masonry, and even granite.

Once again, I used the benchmark of the .30-06 Armour Piercing (Damage 4 AP 2) to start with a base. Experimental testing done by The Ammo Channel has shown that an .30-06 M2 Armour-Piercing round [AMMOTEST: 30 Caliber M2 (30-06) Armor Piercing Penetration Tests - Military Surplus Ammo https://www.youtube.com/watch?v=hzYH8ap1TDo, Jun 21, 2013, retrieved July 1st, 2023] will cleanly penetrate 4" of Portland Concrete, but is stopped by 5". Due to the limitations of the Storyteller system, distance is not being factored into this. I then picked figures for the US Navy Mark 7 16"/50-calibre Main Battery Guns firing the Mark 8 Armour Piercing Capped "Superheavy" shell, which at 10,000 yards, will penetrate 27.5 feet or 8.4 metres of high strength concrete [Tony DiGuilian, USA 16"/50 (40.6cm) Mark 7 - NavWeaps http://www.navweaps.com/Weapons/WNUS_16-50_mk7.php, William H. Garzke, Jr. and Robert O. Dulin, Jr., "Battleships: United States Battleships, 1935 - 1992"] at an impact angle of 0 degrees.

I then aligned both those figures to their Durability equivalence in Rolled Homogenous Armour under "Vehicle Armour", and then created this chart via interpolation.

This table isn't merged into the book yet, I have to add some other stuff but it's a preview of what's to come.

Thickness of Concrete in Feet and Metres to Durability

Code:

m (ft)      Durability  |       m (ft)      Durability  |       m (ft)      Durability  |       m (ft)      Durability
0.08(0.25)      4       |       3.12(10.25)     243     |       6.17(20.25)     485     |       9.22(30.25)     727
0.15(0.5)       7       |       3.2(10.5)       249     |       6.25(20.5)      491     |       9.3(30.5)       733
0.23(0.75)      13      |       3.28(10.75)     255     |       6.32(20.75)     497     |       9.37(30.75)     739
0.3(1)          19      |       3.35(11)        261     |       6.4(21)         503     |       9.45(31)        745
0.38(1.25)      25      |       3.43(11.25)     267     |       6.48(21.25)     509     |       9.53(31.25)     751
0.46(1.5)       31      |       3.51(11.5)      273     |       6.55(21.5)      515     |       9.6(31.5)       757
0.53(1.75)      37      |       3.58(11.75)     279     |       6.63(21.75)     521     |       9.68(31.75)     763
0.61(2)         43      |       3.66(12)        285     |       6.71(22)        527     |       9.75(32)        769
0.69(2.25)      49      |       3.73(12.25)     291     |       6.78(22.25)     533     |       9.83(32.25)     775
0.76(2.5)       55      |       3.81(12.5)      297     |       6.86(22.5)      539     |       9.91(32.5)      781
0.84(2.75)      61      |       3.89(12.75)     303     |       6.93(22.75)     545     |       9.98(32.75)     787
0.91(3)         67      |       3.96(13)        309     |       7.01(23)        551     |       10.06(33)       793
0.99(3.25)      74      |       4.04(13.25)     315     |       7.09(23.25)     557     |       10.13(33.25)    799
1.07(3.5)       80      |       4.11(13.5)      321     |       7.16(23.5)      563     |       10.21(33.5)     805
1.14(3.75)      86      |       4.19(13.75)     327     |       7.24(23.75)     569     |       10.29(33.75)    811
1.22(4)         92      |       4.27(14)        334     |       7.32(24)        575     |       10.36(34)       817
1.3(4.25)       98      |       4.34(14.25)     340     |       7.39(24.25)     581     |       10.44(34.25)    823
1.37(4.5)       104     |       4.42(14.5)      346     |       7.47(24.5)      587     |       10.52(34.5)     829
1.45(4.75)      110     |       4.5(14.75)      352     |       7.54(24.75)     593     |       10.59(34.75)    835
1.52(5)         116     |       4.57(15)        358     |       7.62(25)        600     |       10.67(35)       841
1.6(5.25)       122     |       4.65(15.25)     364     |       7.7(25.25)      606     |       10.74(35.25)    847
1.68(5.5)       128     |       4.72(15.5)      370     |       7.77(25.5)      612     |       10.82(35.5)     853
1.75(5.75)      134     |       4.8(15.75)      376     |       7.85(25.75)     618     |       10.9(35.75)     860
1.83(6)         140     |       4.88(16)        382     |       7.92(26)        624     |       10.97(36)       866
1.91(6.25)      146     |       4.95(16.25)     388     |       8(26.25)        630     |       11.05(36.25)    872
1.98(6.5)       152     |       5.03(16.5)      394     |       8.08(26.5)      636     |       11.13(36.5)     878
2.06(6.75)      158     |       5.11(16.75)     400     |       8.15(26.75)     642     |       11.2(36.75)     884
2.13(7)         164     |       5.18(17)        406     |       8.23(27)        648     |       11.28(37)       890
2.21(7.25)      170     |       5.26(17.25)     412     |       8.31(27.25)     654     |       11.35(37.25)    896
2.29(7.5)       176     |       5.33(17.5)      418     |       8.38(27.5)      660     |       11.43(37.5)     902
2.36(7.75)      182     |       5.41(17.75)     424     |       8.46(27.75)     666     |       11.51(37.75)    908
2.44(8)         188     |       5.49(18)        430     |       8.53(28)        672     |       11.58(38)       914
2.51(8.25)      194     |       5.56(18.25)     436     |       8.61(28.25)     678     |       11.66(38.25)    920
2.59(8.5)       200     |       5.64(18.5)      442     |       8.69(28.5)      684     |       11.73(38.5)     926
2.67(8.75)      207     |       5.72(18.75)     448     |       8.76(28.75)     690     |       11.81(38.75)    932
2.74(9)         213     |       5.79(19)        454     |       8.84(29)        696     |       11.89(39)       938
2.82(9.25)      219     |       5.87(19.25)     460     |       8.92(29.25)     702     |       11.96(39.25)    944
2.9(9.5)        225     |       5.94(19.5)      467     |       8.99(29.5)      708     |       12.04(39.5)     950
2.97(9.75)      231     |       6.02(19.75)     473     |       9.07(29.75)     714     |       12.12(39.75)    956
3.05(10)        237     |       6.1(20)         479     |       9.14(30)        720     |       12.19(40)       962

This chart assumes construction grade high strength Portland Concrete, which has a compressive strength of approximately 5,000 psi after curing. I understand that penetration and hardness is a huge area that multiple Ph.D level thesises could be published on, but we're doing gaming, not engineering, so I'm using it as a rough guideline to draw a few simple rules of thumbs.

Different materials have different properties, and so what I've determined are the following bounds for other materials:

Packed Sand - When penetrating into the earth (such as in the case of a bunker buster bomb), a quick rule of thumb is to imagine that every foot of solid reinforced concrete equals about ten feet of hard-packed earth and sand. So for instance, two feet of hard-packed sand would equal Durability 4, as opposed to two feet of reinforced concrete would equal Durability 43.

Bricks - Modern construction-grade bricks typically have a compressive strength of approximately 1/5th that of high strength concrete, so we take 1/5th of the listed values if the barrier is made from bricks. For instance, a 9" thick brick wall around a mansion would provide Durability 3: enough to provide some ballistic protection against an assault rifle, but a 6" thick brick wall would come out to Durability 2 and could be shot through by the same assault rifle.

Masonry - Stone masonry can be double the strength of bricks or greater, depending on the type and arrangement of the stones used, the fitment of the stones, and the skill of the mason. For good quality masonry, we take 2/5th of the listed value if the target is made from solid stone masonry. Note that castles were rarely solid masonry: very often, they were masonry on the outside, but were hard-packed sand on the inside (see the entry above), so this has to be taken into account when making walls of large fortifications, such as castles. Not all castles were masonry, even; some of the historic buildings and palaces in Russia are actually made of bricks and are simply covered in plaster and paint which needs to be reapplied every year.

White Oak - White Oak has a compressive strength perpindicular to its grain of 1,070 psi [https://www.woodworkweb.com/woodwork...strengths.html, retrieved July 17th, 2023], which places it about on the order of the strength of bricks. A 2-foot solid layer of white oak armour, typical for 17th Century First Rate Line of Battle Ships (using the old British "rating") system would count as Durability 8.

Granite - Granite can be around three to four times the compressive strength of construction grade concrete, depending on how the concrete is reinforced and poured and the age of the concrete (it can take some time for concrete to cure to its full strength), however it's not nearly as effective at resisting penetration compared to rolled homogenous armour, mostly due to issues with it shattering when struck. Granite counts for one and a half times (x1.5) the Durability of construction grade concrete, for the equivalent thickness. So a foot of Granite would count for Durability 29, a foot of concrete would count for Durability 19, and a foot of hardened ballistic grade steel plate (300mmRHA) would count for Durability 51 [See Also: Gods of Iron Vehicle Armour].

Round to the nearest whole number when calculating.

Composite Cover
When layering armour types, take the net thickness of each individual layer, and add them together.

Example of Play: a castle wall consisting of one foot of masonry on the outside, a foot of bricks on the inside, and four feet of sand in between would be done as the following:

A foot of construction grade concrete counts for Durability 19, but the Masonry only counts as 2/5th of that, which comes to 7.6, or Durability 8.

Four feet of construction grade concrete counts as Durability 92, but because it's sand, not concrete, this comes to Durability 9.

Another foot of concrete would count for Durability 19, but bricks only count for 1/5th of that, which leaves us with 3.8 or Durability 4.

Thus, a siege cannon would need to have a Damage output of or Damage output plus Armour Piercing quality of 21 in order to penetrate the cover. A siege cannon with Damage 10 might be able to shoot through the outer wall and penetrate the outer masonry, but the cannonballs it fires will come to a stop in the layer of packed sand inbetween the outer Masonry and the brick work.

RoadMap

There are still a few major and minor items to do, so I'm setting this here to remind myself for future references and to give a bit of a "next stop" in the road map.

- The explosives update needs to be done. I'm planning to create an explosives formula that will allow blast radii and damage/force to be calculated from explosive brisance, charge size, and the presence of fragments. I'm considering adapting one of the functions from GURPS, albeit greatly simplified.
- Apply the rule of size scaling to explosive damage done, as per Armoury 1st Edition.
- Mechanics for HESH rounds need to be added.
- Mechanics for Degradation to armour and cover need to be added.
- 30mm cannons, 25mm cannons, and 20mm cannons still have placeholder values being used in their tables. By the charts, they should have a damage base of 10, 9, and 8 respectively.
- Some examples of play need to be fixed in accordance with the gameplay rules.
- Virtually all the missiles need to be redone after the explosive update.
- The USN Mk. 7 16"/50-calibre guns are going to be redone to tune damage, as I've retrieved better tables for them. In the future for Seas of Steel I would like to make them take into account both deck and side armour. This will likely need a complete and total do-over.
- Anti-aircraft weaponry needs to have Accuracy and TDD redone in order to prevent nonsensical situations that can arise if Acc and TDD are set to 1 and 1 respectively and common sense is not applied, such as players using an 120mm Gun M1 Superheavy Anti-Aircraft Gun to make a called shot to an enemy character's eye at a penalty of 0 at altitudes of 5,000m. (For reference, no this never happened in game, I just realized that it was possible by the "letter of the rules.")

Works Cited

The Ammo Channel, AMMOTEST: 30 Caliber M2 (30-06) Armor Piercing Penetration Tests - Military Surplus Ammo - https://www.youtube.com/watch?v=hzYH8ap1TDo, Published June 21st, 2013, retrieved July 1st, 2023

Tony DiGuilian, USA 16"/50 (40.6cm) Mark 7 - NavWeaps - http://www.navweaps.com/Weapons/WNUS_16-50_mk7.php, Published July 17th, 2023, Retrieved July 17th, 2023.

William H. Garzke, Jr. and Robert O. Dulin, Jr., Battleships: United States Battleships, 1935 - 1992

Woodworkweb, Wood Strengths - https://www.woodworkweb.com/woodwork...strengths.html, Publication date not listed, Retrieved July 17th, 2023.

Updated July 18th 2023: Tuned the Durability factor of Granite.

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Homebrew vehicular and combined arms combat in CofD

Homebrew vehicular and combined arms combat in CofD

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