Advanced Cannon

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Advanced Cannons, or Advanced Projectile Systems (APS), are even more customizable than CRAM Cannons, at the cost of maximum shell size.

Currently being reorganised and expanded.

Cannon components[edit | edit source]

An advanced cannon system consists of two main parts, the cannon itself, and ammunition production.

Firing Piece[edit | edit source]

Main article: Advanced Firing Piece

The Adv. Firing Piece is the Core Block of the cannon itself. The number of barrels can be selected from one to six.

  • Overclocking: A cannon can "borrow" up four seconds of cooldown. Once this time is used up, the cannon returns to its normal sustained rate of fire. Recoil and inaccuracy are multiplied by a factor (1 + overlock seconds used), i.e. up to 5x.

Mantlet[edit | edit source]

Main article: Mantlet

A mantlet goes directly on the front of the Advanced Firing Piece. It determines the traverse range of the barrel. The first, lower number corresponds to what a 500mm gauge, while the second, higher number corresponds to a 50mm gauge.

Mantlets count as 1m in barrel-length – If you'd need a 5m barrel for propellant burn, it's sufficient to use a mantlet and a 4m barrel.

Mantlet Azimuth in ° Minimum elevation in ° Maximum elevation in °
Omni Mantlet (1m) 10 to 30 -10 to -30 10 to 30
Elevation Mantlet (1m) 5 to 20 -20 to -40 20 to 40
Omni Mantlet (3x3m) 40 to 60 -40 to -60 40 to 60
Elevation Mantlet (3m) 5 to 10 -45 to -65 45 to 65
AA Mantlet (2) 5 -5 to -15 80 to 100

Multiple barrels results in an additional effective gauge for the purposes of traverse range:

Number of barrels 1 2 3 4 5 6
Extra gauge (mm) 0 500 450 600 650 650

Traverse range is always at least 5 degrees in each direction. Cannons can be built without a mantlet, in which case this is their traverse range.

Barrel[edit | edit source]

Main article: Barrel (APS)

Barrels go on the front of the mantlet. More barrels increase accuracy, and may be required to achieve maximum muzzle velocity for a given amount of propellant.

The cannon's Q-menu allows to split these to allow for multi-barrel setups. This decreases the gauge. Each barrel cools down independently, allowing a higher maximum rate of fire.

For a barrel length \ell_b and n_b barrels the traverse per second is

\frac{1}{\left(0.1 + 0.25 \pi d^2 \ell_b n_b\right)^{0.7}} \approx \frac{287^\circ}{\left(1 + 2.5 \pi d^2 \ell_b n_b\right)^{0.7}}

Note that this does not apply to heavy barrels. These have lower traverse speed, but unknown how much lower exactly.

Gauge Snake[edit | edit source]

Gauge Increases go behind the Advanced Firing Piece. Gauge refers to the diameter of shells that are fired from the cannon. For a single-barrelled cannon, the diameter starts at 60 mm. The first Gauge Increase adds another 60 mm; additional Gauge Increases are each 0.98 times as effective as the last. The cap is 500 mm at 8 Gauge Increases.

Having multiple barrels will divide the gauge by 20/10 for 2 barrels, 20/9 for 3, 20/8 for 4, and so on.

Gauge Increases Barrels
1 2 3 4 5 6
0 60.00 30.00 27.00 24.00 21.00 18.00
1 120.00 60.00 54.00 48.00 42.00 36.00
2 178.80 89.40 80.46 71.52 62.58 53.64
3 236.42 118.21 106.39 94.57 82.75 70.93
4 292.90 146.45 131.80 117.16 102.51 87.87
5 348.24 174.12 156.71 139.30 121.88 104.47
6 402.47 201.24 181.11 160.99 140.87 120.74
7 455.62 227.81 205.03 182.25 159.47 136.69
8 500.00 250.00 225.00 200.00 175.00 150.00
Cooling Units Seconds to cool
1 2 5
0 1 2 5
1 0.9200 1.8400 4.6000
2 0.8464 1.6928 4.2320
3 0.7787 1.5574 3.8934
4 0.7164 1.4328 3.5820
5 0.6591 1.3182 3.2954
6 0.6064 1.2127 3.0318
7 0.557847 1.1157 2.7892
X 0.92^X*1 0.92^X*2 0.92^X*5

Ammo[edit | edit source]

  • Autoloader: These go on the sides of the Advanced Firing Piece or Gauge Increases or next to each other. Each Autoloader can hold one cartridge ready for firing.
    • Belt Feed Autoloader: Fires 5 times as fast as a conventional 1m autoloader, but cannot fire and reload at the same time, and cannot start firing until 6 seconds after its clip is full.
  • Ammo Clip: These go on the sides, top, or bottom of Autoloaders, or the top only of Belt-Fed Autoloaders. They hold cartridges ready for loading.
    • For cartridges of up to 250 mm gauge, one ammo clip holds \min \left( \left\lceil \frac{2}{d} \right\rceil, 64 \right) cartridges in two stacks.
    • For cartridges of greater than 250 mm gauge, one ammo clip holds \left\lceil \frac{1}{d} \right\rceil cartridges in a single stack.
  • Ammo Input Feeder: These go on the front or back of Autoloaders or Ammo Clips. These transfer cartridges from the supply to the clip.
  • Ammo Ejector: These go on Autoloaders. When an associated ejector, autoloader, or clip is destroyed, instead of detonating, all associated shells will be ejected at a speed of 50 m/s, plus a random value of up to 15 m/s along each axis. This prevents the propellant from detonating. An Emergency Ejection Fuse makes this completely safe, otherwise the shells can still trigger inside your craft.

Stored ammunition explodes when an autoloader or clip is destroyed. Powder modules do 20% as much damage as flak modules for this purpose, but are computed separately from true flak modules.

Railguns[edit | edit source]

Railguns use electricity to increase the velocity of the fired shells. The increased velocity also increases the kinetic damage and AP.

This article is a stub. You can help From the Depths Wiki by expanding it.

  • Railgun Magnet Attaching Feature: Attaches to the side of the Firing Piece.
  • Railgun Barrel Magnet: Attaches in a line to the Attaching Feature. Analogous to Laser Destabilizers. The first magnet discharges a base of 2% of stored energy per shot, with subsequent magnets discharging 0.9 times as much as the last. For n_m magnets, the proportion discharged per shot is
20 \% \cdot \left(1 - 0.9^{n_m} \right)
  • Railgun Charger: Attaches to Gauge Increases, Gauge Coolers, or Connectors. Each charger provides 100 charge per second times the railgun overclock, and each unit of charge costs energy equal to the railgun overclock.

Ammunition Production[edit | edit source]

Ammo Controller[edit | edit source]

Main article: Ammo Controller

The Ammo Controller is the core component of ammunition production.

Ammo Customisers[edit | edit source]

Ammo Customisers go in a line in front of the ammo controller. Each customiser adds two shell-modules – A single module customiser allows to make shells with an uneven number of modules, often allowing for another module without exceeding the Autoloader's length..

You can only connect 30 customisers to a controller, limiting maximum shell-length (although shells like that are impractical anyway).

Strategy and Examples[edit | edit source]

Cannon-Design[edit | edit source]

Shell-Design[edit | edit source]

Maths[edit | edit source]

Scary numbers to optimise shells and cannons further, or design things without opening the game. None of the following is necessary to design effective cannons.

Shell Design[edit | edit source]

To avoid confusion with the consumable resource "ammo parts", we will refer to the items in a cartridge as "modules".

We will refer to the entire collection of modules as the "cartridge" and the modules minus the casing as the "shell". Let n be the number of modules in the cartridge, and n_s be the number of modules in the shell.

Modules[edit | edit source]

Each module is a cylinder with diameter specified by the shell diameter d in metres, and length equal to the diameter. The volume of a cartridge is then

V = \frac{1}{4} \pi n d^3

Likewise, let V_s be the volume of the shell (projectile) only.

Category Module Speed modifier AP modifier Kinetic damage modifier Maximum length (mm) Detectability Factor Description
Casing Railgun Casing 1 1 1 1 Increases velocity from railgun charge by 50%. Additional railgun casings past the first are each 90% as effective as the last.
Casing Gunpowder Casing 1 1 1 1 Determines muzzle velocity. More casings mean higher velocity. Also increases cooldown.
Shell Rear Only Graviton Ram 0.9 0.5 1 1 Converts kinetic damage to force.
Shell Rear Only Base Bleeder 1.1 1 1 100 1.1 Multiplies velocity by 1.2.
Shell Rear Only Supercavitation Base 1 1.5 1.5 100 1 Removes water drag entirely, as well as the chance to bounce off the water's surface. Reduces EMP damage, explosive/flak damage and radius, and frag count to 75%. Useful when trying to take out submarines, or adding guns to a submarine.
Shell Rear Only Visible Tracer 1 1 1 100 1.5 Improves accuracy by a factor of 2 for a few seconds after firing. Bonus reduced if shell-velocity differs.
Shell Middle Frag Warhead Body 1 1.5 2.5 1 Produces fragments. Number and damage depend on gauge. Damage also depends on cone-angle.
Shell Middle Solid Warhead Body 1.3 2 5 1 No special effects, most useful for kinetic shells
Shell Middle Sabot Warhead Body 1.75 3.6 2.7 1 Reduces EMP damage, explosive/flak damage and radius, and frag count to 25%.
Shell Middle HE Warhead Body 1 1.5 2.5 1 Deals explosive damage.
Shell Middle Grav. Compensator 1 1.5 1.5 100 1 Shell is always affected by at least its starting gravity. This lets the shell take the aimed trajectory when firing into orbit. Also doubles time before drag sets in, making high-angle guns more viable.
Shell Middle Flak Warhead 1 0.4 2.5 1 Deals less explosive damage than the HE warhead body, but in a larger radius.
Shell Middle Smoke Warhead 1 0.4 0.4 1 Creates smoke on hit, provided the shell is at least 0.2m in diameter. Smoke follows vehicles if the shell impacted on the vehicle. Useful to silence enemy LAMS or lasers.
Shell Middle Inertial Fuse 1 0.4 1 200 1 Detonates when deflected by a surface (material, shield, water). Deflection angle to trigger can be set.
Shell Middle Proximity Fuse 1 0.2 0.5 200 1 Detonates the shell at a set distance. Only checks directly in front of the shell – usually not a good choice.
Shell Middle EMP Warhead 1 0.5 2.5 1 Deals EMP damage.
Shell Middle Stabiliser Fin Body 1 1.5 3 300 1 Multiplies inaccuracy by 0.8 each.
Shell Middle Altitude Fuse 1.1 1.5 2.5 200 1 Detonates at a set altitude. Can be set automatically when using a Laser Targeter (APS).
Shell Middle Timed Fuse 1.1 1.5 2.5 200 1 Detonates at a set time after firing. Can be set automatically when using a Laser Targeter (APS).
Shell Middle Penetration Depth Fuse 1.1 1.5 2.5 200 1 Detonates at a set time or depth after first impact. Depth only counts blocks (air does not count).
Shell Middle Emergency Ejection Fuse 1 1 1 200 1 Prevents detonation if the shell is ejected. Needs an ejector on the loader to work.
Shell Middle Shaped Charge Secondary 1 0.1 0.5 1 Uses all HE modules behind it as a second shaped charge warhead. Allows penetration of ERA.
Shell Nose Only HE Head 1.4 0.1 2.5 1 A HE warhead with better stats for the nose of the shell.
Shell Nose Only Disruptor Conduit 0.8 0.2 0.3 3 Shield-killer. Reduces EMP to 25%. Needs 125 listed EMP per shield strength to kill the shield in one hit (i.e. 1250 for a max-strength shield).
Shell Nose Only Squash Head 1.3 0.3 0.4 1 Turns the shell into HESH, using all the HE just behind the head.
Shell Nose Only Frag Head 1.4 0.1 2.5 1 A frag warhead with better stats for the nose of the shell.
Shell Nose Only EMP Head 1.4 0.1 2.5 1 An EMP warhead with better stats for the nose of the shell.
Shell Nose Only AP Capped Head 1.5 3.5 10 1 The standard head for most kinetic shells. Provides moderate AP with high kinetic damage.
Shell Nose Only Composite Head 1.6 4.5 5 1 Increased muzzle velocity and AP compared to the AP Capped Head but decreased kinetic damage.
Shell Nose Only Skimmer Tip 1.75 3 3 1 Doubles maximum angle of incidence at which the shell bounces off water. Guaranteed to bounce off the water if within the incidence angle. Highest speed-modifier amongst all non-sabot modules.
Shell Nose Only Flak Head 1.4 0.1 2.5 1 A Flak warhead with better stats for the nose of the shell.
Shell Nose Only Sabot Head 2.05 6.75 1.8 1 Reduces EMP damage, explosive/flak damage and radius, and frag count to 25%. Has the highest AP and speed of any module however.
Shell Nose Only Shaped Charge Head 1.4 0.1 0.5 1 Uses all HE modules behind it to blast a stream of superheated copper into the target, creating HEAT damage.
Shell Nose Only Hollow Point Head 1.4 0.25 4 1 Spreads all kinetic damage laterally as thump damage with AP 10.

Ballistics[edit | edit source]

Muzzle Velocity[edit | edit source]

Let n_p be the number of propellant modules. The muzzle velocity from propellant is

v = 700 \frac{n_p}{n} s V_s^{0.03} \approx 695 \frac{n_p}{n} s n_s^{0.03} d^{0.09}

s is the speed coefficient, defined below.

Projectiles inherit the velocity of the cannon they are fired from, and this affects all velocity-dependent characteristics, namely AP and kinetic damage.

Once in flight, projectiles are affected by gravity and drag in water (but not air). However, this does not change AP or kinetic damage.

Railguns[edit | edit source]

For a charge expenditure of q and n_r railgun casings, the muzzle velocity is increased by

v_r =  \frac{8^{0.5} q^{0.5}}{n_s^{0.25} \left(5d\right)^{0.75}} s \approx 0.8459 \frac{q^{0.5}}{n_s^{0.25} d^{0.75}} s

Railgun casings increase this by a factor

\left(1 + 5 \left(1 - 0.9^{n_r} \right)\right)

Speed Coefficient[edit | edit source]

A factor in muzzle velocity is the speed coefficient, which is a weighted average of the speed modifiers s_i of the (non-casing) parts, where each component i starting at the head has half the weight of the previous:

s = \frac{\sum 0.75^i s_i}{\sum 0.75^i}

The head will thus always determine at least 25% of the speed coefficient.

For example, suppose the shell has a Composite Head (speed modifier 1.6), a Solid Warhead Body (speed modifier 1.3), and a Supercavitation Base (speed modifier 0.9). Then we have

s_0 = 1.6

s_1 = 1.3

s_2 = 0.9

s = \frac{0.75^0 \cdot 1.6 + 0.75^1 \cdot 1.3 + 0.75^2 \cdot 0.9}{0.75^0 + 0.75^1 + 0.75^2} \approx 1.33

Propellant Burn[edit | edit source]

The length of barrel needed for optimal propellant burn is

\ell_{bp} = 16 n_p d

If the barrel is too short, muzzle velocity will be reduced proportionally.

Effective Time[edit | edit source]

The time a shell will travel before suffering drag is

10 s n_s

Ammunition and Reloading[edit | edit source]

Cost[edit | edit source]

c = \frac{8}{0.2^{1.5}} n d^{1.5} \approx 89.44 n d^{1.5}

Note that the cartridge length has greater effect than for reloading.

Filling Ammo Clips[edit | edit source]

This is the "time to pass shell to ammo clip". Specifically, after this many seconds pass, each Input Feeder checks whether it can reload its associated autoloader. If there is space, the Input Feeder moves one cartridge from the supply to the autoloader's clips. Otherwise, it retries every second.

t_a = 100 V^{0.5} \approx 88.6 n^{0.5} d^{1.5}

Loading[edit | edit source]

This is the "expected reload time from clip". Specifically, it is the time taken for a cartridge to move from a clip to its autoloader. Let n_a be the number of autoloaders attached to the firing piece and n_{cf} be the number of faces of the autoloader with a clip attached.

t_b = 50V^{0.5} \frac{n_a^{0.25}}{n_{cf}^{0.5}}

50 V^{0.5} is the value shown in the shell designer. n_a^{0.25} is the "load time increase due to complexity".

  • If an autoloader has no clips, the autoloader can be loaded directly from the input feeder, but can only be reloaded if it has been empty for at least 1.5 times this clip to autoloader time, times the complexity factor (see below).

Barrel Cooldown[edit | edit source]

Let n_c be the number of cooling units.

t_c = 6 \left( \frac{d}{0.2} \right)^{1.5} n_p^{0.5} 0.92^{n_c} \approx 67.08 d^{1.5} n_p^{0.5}  0.92^{n_c}

Recoil[edit | edit source]

This article may need updating to the game's current version. Use information provided here with care.
Please help improve this if you can. The Discussion page may contain suggestions.
Reason: "Absorbers now reduce recoil by a set amount, and have to regenerate; Missing info on muzzle break"

Let \ell_h be the total length of Hydraulic Recoil Absorbers. The displayed recoil is

J_D = \left( \frac{2 \times 10^4}{0.2^{1.95}} \cdot n_p^{0.65} d^{1.95} + 10 q \right) 0.95^{\ell_h} \approx \left( 4.613 \times 10^5 \cdot n_p^{0.65} d^{1.95} + 10 q \right) 0.95^{\ell_h}

The units are kN frames, and currently depend on game speed.

Inaccuracy[edit | edit source]

Let \ell_b be the length of the barrel, including all variants, and the Mantlet.

\theta = 4^\circ \cdot \frac{n_s d^{0.5}}{\ell_b - n_p d}

If railgun charge is used to boost accuracy, the accuracy is improved by a factor

1 + \frac{0.001 q}{n_s d}

Health and Detection[edit | edit source]

Shells have a health of 1000 V_s times any modifiers from modules.

Detectable range is 500 V_s^{2/3} times any modifiers from modules, times a factor from firing altitude. This increases linearly from 1 at 10 m to 4 at 400 m.

Damage and other hit effects[edit | edit source]

AP[edit | edit source]

Let a be the AP coefficient of the shell.

a = \frac{\sum 0.75^i a_i}{\sum 0.75^i}

If the shell has fewer than 3 modules, the missing modules are treated as having an AP modifier of 0.5.

\text{AP} = 0.01 a v

Kinetic Damage[edit | edit source]

Let k be the kinetic damage coefficient. Unlike the speed and AP coefficients, this is an unweighted average.

k = \frac{\sum k_i}{n_s}

If the shell has fewer than 3 modules, the missing modules are treated as having a kinetic modifier of 0.5.

The kinetic damage is then

D = 1.25 k v \left( \frac{d^3 n_s}{0.2^3} \right)^{0.65}

HE Warheads[edit | edit source]

For n_w HE modules (count Shaped Charge and Squash Heads without HE modules as half a HE module), the explosive damage is approximately

D = 500 \left( \frac{d}{0.2} \right)^{1.95} n_w^{0.65}

and the radius is

r = \left( \frac{D}{10} \right)^{0.5}

Note that all explosives have a hard cap on radius of 30m.

EMP Warheads[edit | edit source]

For n_w EMP modules, the EMP damage is approximately

200 \left( \frac{d}{0.2} \right)^{1.95} n_w^{0.65}

Flak warheads[edit | edit source]

For n_w flak modules, the explosive damage is approximately

D_f = 250 \left( \frac{d}{0.2} \right)^{1.95} n_w^{0.65}

and the radius is

r_f = D_f^{0.5}

The flak effect is completely separate from any HE effect. All explosives have a hard cap on radius of 30m. Note that flak can "snap" onto a target-vehicle that is within its radius, and will then deal damage within 30m from the closest point. Also, the cap only applies to blocks - missiles and the avatar can be damaged at any range.

Fragmentation warheads[edit | edit source]

The number of fragments per module is

\left\lceil 10 \left( \frac{d^2}{0.2^3} \right)^{0.65} \right\rceil

and the damage per fragment is

This article may need updating to the game's current version. Use information provided here with care.
Please help improve this if you can. The Discussion page may contain suggestions.
Reason: "Damage now depends on cone-angle"

200 \left( \frac{d}{0.2} \right)^{0.5}

Fragments have AP 6.

Squash heads[edit | edit source]

This article may need updating to the game's current version. Use information provided here with care.
Please help improve this if you can. The Discussion page may contain suggestions.
Reason: "HESH now generates spalling in several places in a semi-circle in front of it; unknown if formulas are still accurate"

Spalling metric is

15 \left( \frac{d}{0.2} \right)^{1.95} n_w^{0.65}

where n_w is the total special factor of all HE warheads, counting the squash head itself as 0.5.

Upon hitting a surface the squash head ejects damaging particles on the opposite side. The number of particles is equal to the spalling metric divided by the number of AC-metres passed through.

Each particle does 200 damage and has AP equal to twice the armour of the last material passed through.

Thump damage is

400 \left( \frac{d}{0.2} \right)^{1.95} n_w^{0.65}

and is applied at AP 10.

Shaped charge head[edit | edit source]

This article may need updating to the game's current version. Use information provided here with care.
Please help improve this if you can. The Discussion page may contain suggestions.

For penetration factor \alpha, penetration metric is

30 \left( \frac{d}{0.2} \right)^{1.95} \left(\alpha n_w \right)^{0.65}

and particulate count is approximately

10 \left( \frac{d}{0.2} \right)^{1.95} \left(\left(1 - \alpha \right) n_w\right)^{0.65}

where n_w is the total special factor of all HE warheads, counting the shaped charge head itself as 0.5.

Regardless of the values shown in the customizer, the actual penetration factor \alpha is always between 0.05 and 0.95, and the actual special factor for HE warheads cannot be less than 0.01.

Each particulate deals 200 damage at AP 10.

Graviton ram base[edit | edit source]

Each point of kinetic damage converted produces 100 kN s of impulse. The translational component of the force may be converted to torque using the slider.

Trajectory[edit | edit source]

Skimming[edit | edit source]

On reaching within 0.25 m of the surface of water, a shell has a 50% chance to skim (reflect) off once provided the shell is travelling no more than \arcsin 0.15 \approx 8.63^\circ from horizontal. This instantly reduces the velocity of the shell by 10%. Some shell modules induce different behaviour:

  • A shell with a Supercavitation Base will never skim unless it also has a Skimmer Tip.
  • A shell with a Skimmer Tip will skim up to 1000 times with 100% probability, and the maximum skim angle is increased to \arcsin 0.30 \approx 17.46^\circ.

Drag[edit | edit source]

Shells are unaffected by drag when in air, until reaching their effective time (as listed in the Ammo Customiser screen). In water, they slow down exponentially with an (instantaneous) deceleration rate of 70% of their velocity per second. Shells with a Supercavitation Base ignore underwater drag.