A question about beam weapon design?

[Jorgen_CAB (OP)]

I wonder some about the mechanics of designing different beam weapon system and the ratio of weapons per fire control.

First question is about the tracking speed of fire control and turrets (or ships speed). If my tracking speed is higher than the speed of the target do the weapon get a bonus to hit and if so how much?

For example, is it meaningful to give a fire control a higher tracking speed on a small ship that intend to fire on a slower ship. Let's say you put a beam on a FAC and you intend to use it against a slower target. Your FAC has a speed of 10000 km/s but your target has at most 5000 km/s in speed. Are there any point to giving your craft a fire control with a tracking speed of 10000 km/s?

Another question is about the number of fire control per weapon banks/turrets on a ship. For example the number of long range area defense fire control versus short range fire controls if you mount both weapon types on a vessel?

Is it really useful with more than one slow tracking fire control for a ships main beam weapon, do you really want to fire that often on two different targets with your main heavy beams?

When it comes to the range of fire controls, what is the though about  giving them a much greater range than the weapon?
The greater the range of your fire control the easier you hit at the extreme range of your weapon, even if you can't even shoot at the far reaches of the fire control. I mean, even mounting a heavy weapon with a fire control that mach its range will find you to miss almost every time at extreme ranges.

I think that is enough for now on the questions.

[Redshirt]

I believe having a higher tracking speed prevents a penalty to hit, rather than gives a bonus. As for using a 10k km/s fire control... eventually you're going to come across a target moving that fast. (Enemy FAC maybe?)

Extra short range fire control will let you track more incoming missile salvos. Extra long-range (slower) fire control will let you track multiple ships- your big destroyer can now fire at two different enemy FAC at once. Additionally, it gives you some redundancy if one fire control happens to be destroyed during combat. It will happen, trust me.

Giving your fire control greater range than your beam weapons will help combat ECM. It will also mean you don't have to upgrade your fire controls every time you design a new weapon.

[Jorgen_CAB (OP)]

Ok, thanks for your answer... so basically if you plan to use the weapon at slower targets there is no point in giving it additional tracking speed, thus you may save some weight on the fire control for other things.

One other question is about turrets and mounting several guns in one turret. If a turret fire at a swarm of missiles from a single salvo can it hit more than one missile in that salvo or is it wiser to put PD weapons in single turrets?

And as a clarification to your remark about range... it is my understanding that the range of the fire control is what give you the to hit chance for range rather than the weapons individual (or actual) range. For example a Gauss cannon with a range of 30k get a higher chance to hit at 30k distance with a fire control with a maximum distance of 80k than one with a maximum distance of 40k.

[metalax]

All the guns in a turret will target a single salvo of missiles. Each hit can destroy a different missile within that salvo. Whether it is better to use multiple turrets depends on if you are going to add additional firecontrols for the smaller turrets to enable them to target seperate salvos.

Yes, hit chance is based on the firecontrol range. If this is longer than the weapons range it is simply unable to hit beyond the weapons range.

[Jorgen_CAB (OP)]

Then comes the question, how many fire controls for the ratio of cannons?

Let's say that I have four twin gauss cannons on a ship for PD duty, how many DP fire controls should I use?

[Theokrat]

Then comes the question, how many fire controls for the ratio of cannons?

Let's say that I have four twin gauss cannons on a ship for PD duty, how many DP fire controls should I use?

That depends on the salvos fired by the enemy. Basically you need to have at least one firecontrolls for every salvo that arrives at every 5s increment. On the other hand, every firecontroll should have sufficient guns assigned to it to be able to deal with an incoming salvo.

Two examples from the Bureau of Ship Design:

• If you encountered one ship of the "Fletcher" class of Cavgunner, then you would face 50 missiles, bundled together in one large salvo (because of the one firecontroll on the Fletcher). In this case you would only need one FC yourself, more than that would be entirely wasted. If your guns had a 100% chance to destroy the missiles, then you could have 50guns/FC.
• On the other hand, if you were facing a Frankfurt-am-Main class of my Kaiserliche Raumflotte, then you would be have 6 salvos of 4 missiles each incoming. So if you have a 100% chance to shoot down the missiles, you would want a 4guns/FC ratio.

Obviously in most situations you dont know who you will be facing exactly, so your analysis must make some educated guesses. Firstly, firecontrolls are quite expensive, and somewhat bulky, so I would rather advice to use more guns per FC. Secondly, I tend to have some beam-PDs one most of my capital ships, which operate in large groups, so there is always a rather large amount of firecontrolls floating around anyway. So at least for the Raumflotte this resulted in circa 5railguns(a 4 shots) per firecontroll, or 3 gaussguns per FC.

E.g. when only a single salvo of a lot of missiles arrives at every 5s increment, you could do with a single firecontroll.


the enemy uses a single firecontroll for all his missile launchers, then all missiles are in the same salvo.

y fire one salvo

[metalax]

Then comes the question, how many fire controls for the ratio of cannons?

Let's say that I have four twin gauss cannons on a ship for PD duty, how many DP fire controls should I use?

It would depend on what role the ship is playing. My normal practice for point defence is one fire control per four barrels, or one firecontrol per quad turret. If I was building a ship with multiple dual gun turrets instead of quads it would be because I wanted each turret to track a different salvo, so one firecontrol each.

[Jorgen_CAB (OP)]

Ok, I seem to have guessed it right in my estimation. My last ship had two quad cannons and one twin cannon with two fire controls. My thought here was that the twin turret would help the one facing the largest volley after my wide area PD had done its damage first.

Another thing that I'm a little confused about when designing my turrets is the gear percent, this is reduced the more guns I put into a turret. Does this just reflect the amount of gear in relation to the turrets size or does it have any other property when the turret fires in battle?

For example it is more efficient to have one quad 50% gauss cannon instead of a twin 100% gauss cannon turret since the first has less gear on the turret and otherwise have the same hitrate just more shots?

On another note, will crew grade add to a guns hit rate by simply multiply the hit rate of the shots. Such as a 12% crew grade giving a 1.12 modifier?
If that is the case then it seem smaller gauss cannons are preferable over larger ones for PD duty.

[metalax]

There is a modifier to gear size that makes it smaller for multi barrel turrets. I believe it is a 10% saving for a quad, less for tripple and less for a dual. Note that this modifier only applies to space taken up by the tracking gear, space for the weapons and other systems in unaffected. So yes, quad turrets work out more effective if you need more than a small ammount of gear to hit your target tracking speed.

[Theokrat]

Ok, I seem to have guessed it right in my estimation. My last ship had two quad cannons and one twin cannon with two fire controls. My thought here was that the twin turret would help the one facing the largest volley after my wide area PD had done its damage first.

I am not entirely sure you can assign the firecontrolls in such a way that the FC with more barrels would engage the larger salvo, rather than the other way round.

Another thing that I'm a little confused about when designing my turrets is the gear percent, this is reduced the more guns I put into a turret. Does this just reflect the amount of gear in relation to the turrets size or does it have any other property when the turret fires in battle?

The gearing percentage is only used in determining the size (and costs) of the turret, not directly its combat characteristics (although the design choices that lead to different percentages obviously have an effect in battle for other reasons).

For example it is more efficient to have one quad 50% gauss cannon instead of a twin 100% gauss cannon turret since the first has less gear on the turret and otherwise have the same hitrate just more shots?

Yes, in terms of expected hits (or hits on average) both turrets are equal, while the Quad turret has better gearing and is thus slightly smaller and cheaper.

Yet, the average hits are not quite everything. Suppose you are attacked by two missiles flying at the turrets tracking speed. Lets say the distance modifier of the FC thus results in a 90% hitchance modifier. Lets assume no tracking or crew-grade bonus.

• The Twin-100% guns dont have any further modifier. The probability that you can kill both missiles is 81% (=0.9*0.9), and there is a 18% chance that you do get hit by one of the missiles, while with 1% chance you get hit by both missiles
• For the Quad-50% guns there is a further 50% modifier, so you get 4 shots of 45% each. Now there is only a 61% chance that you manage to shoot down both incoming missiles, while with 30% at least one missile leaks through and with a 9% chance that all your shots miss (and you get hit by both missiles)

So effectively, the Quad-50% gaussguns can be much worse than the Twin-100% guns. Note that this is not necessarily the case. Importantly, when tracking and crew-grade bonuses push the initial hit chance of a 6HS gaussgun above 100%, it is certainly worthwhile to reduce its size, as you have pointed out.

[Jorgen_CAB (OP)]

Yes... I know that miniaturizing the gauss gun will make it less accurate to fire at missiles as long as you have equal or less shots as there are missiles in the salvo and you are your gauss cannon are below 100% to hit chance.
But when you factor in large missile swarms that outnumber your number of shots and the facts that you need to concentrate in tech like firing range and tracking speed smaller guns can be much more effective. I actually think a mix of them would work very well depending on your strategy I suppose.

Another consideration for beam design are the fire controls.

Let's say that I have a mix of lasers and gauss on a large point defence cruiser/destroyer type ship for task group defence. Lets say that the ship is armed with 12cm UV lasers and regular gauss guns.
Is there any point in saving some on the size of a control to reduce the tracking speed and gaining more range or should I just put maximum range and tracking speed on area PD fire controls such as with 12cm lasers. Both range and tracking speed will increase my chances to hit missiles considerably in most cases, but it is always a decision about number of fire controls versus the accuracy I get from them and the number of beams.

On my larger cruisers I was going to have three gauss FC and enough cannons to cover them (these are ships of about 32k-38k tones). For them I reasoned that I wanted to have two FC with minimal range and one with double range for better accuracy if I get to fire before the missile strikes and also to tie them against large alpha like strikes.

Also, is there really much idea to spend lots of effort onto the range of your gauss cannons?
The chances of a cannon being able to catch missiles within their range before they strike (another ship, not talking about final fire here) are almost impossible unless you put them on an escort ship that stands at a reasonable distance away from the primary target. Many anti-ship missiles have a speed of between 20k-40k and will pass through the diameter of a 40k gauss equipped escort in more than 50% of the cases in the 5 second rounds. You might be lucky and have your escort driving in the same direction as the missile and increase the chances to fire, but that require allot of effort to attain.

[Theodidactus]

What's the point of putting multiple guns on the same fire control turret. Does each gun get to role its own chance to hit the missile, or do they all have the same roll?

[metalax]

Each gun barrel, or more specificaly, each shot from each gun barrel for those that fire multiple times, gets it's own roll to hit. The point of putting multiple guns on a single firecontrol is that it saves space. If you need multiple shots at a target in any case then having more than one firecontrol per target is awaste of space in your class design.

[Theokrat]

But when you factor in large missile swarms that outnumber your number of shots [...] smaller guns can be much more effective.

Consider it analytically, and you can see that this strategy must be suboptimal.

If there are more missiles that you have shots to engage them, then invariably some missiles will get through. This means that you must have another method of defence lets assume you use shields for the moment) to deal with these leakers. So the question is: Could we get to a better situation if we reduced the beam-defence arrangement and added shields (or vice versa)?

To that end one can compare the marginal utilities (i.e. the effect of adding a bit of tonnage to either category). If one marginal utility is larger than the other, than it would be sensible to increase the size of that component at the expense of the other.

Beam defenses have a constant marginal utility, as long as there are fewer shots than incoming missiles. Each "extra" shot would still be able to engage a target and be able to hit it with the same chance. (The situation would be different if there were more shots than incoming missiles, because that would leave the possibility that the previous shots had already destroyed all targets thus leaving the extra shots increasingly less likely to be able to contribute anything at all. But you explicitly stated that was not the case we are considering, so the marginal utility of beams is constant). So let's say an extra beam-weapon would avoid X damage to our ships.

Shields also have a constant marginal utility, as long as they are constantly recharging. Every shield allows to regenerate Y hitpoints between enemy salvos (in the case of a prolonged attack), or just offers Z hitpoints to begin with (in case of an aplha strike).

Thus we are comparing two fixed numbers. Very likely one of these is larger than the other. Which means that we should either use only use shields, or only beam guns in this scenario - but not both. "Mixing" is just not an optimal strategy as long as you have less shots than incoming missiles. The story is very different though when you have more shots than incoming missiles. Efficiency of extra beam defences quickly falls of, and at some points it makes more sense to add extra shields.

Of course there are other viable options besides shields and beam-defences, notably traditional armour and speed, but similar arguments apply.

Is there any point in saving some on the size of a control to reduce the tracking speed and gaining more range or should I just put maximum range and tracking speed on area PD fire controls such as with 12cm lasers. Both range and tracking speed will increase my chances to hit missiles considerably in most cases, but it is always a decision about number of fire controls versus the accuracy I get from them and the number of beams.

As long as the tracking speed of the FC is lower than the missile it is supposed to engage, you are better off by keeping it large.

Suppose the weapons have a weight of X, and the firecontroll has the weight Y, so the whole system has the weight Z=X+Y. With this you can score a hit with probability P, stemming from various modifiers (tracking speed, distance, crew training, ECM...) . Thus the efficiency of your system could be measures as P/Z=P/(X+Y).

Say we reduce the tracking speed of the FC by a factor of 1/2. The weight of the weapon stays constant at X, while the weight of the FC changes to Y/2, so the weight of the overall system changes to X+0.5*Y. The proability to hit also gets halved to 0.5*P. Thus the Efficiency changes to (0.5*P)/(X+0.5*Y)=P/(2X+Y), which is lower than for the larger system.

On my larger cruisers I was going to have three gauss FC and enough cannons to cover them (these are ships of about 32k-38k tones). For them I reasoned that I wanted to have two FC with minimal range and one with double range for better accuracy if I get to fire before the missile strikes and also to tie them against large alpha like strikes.

Also, is there really much idea to spend lots of effort onto the range of your gauss cannons?
The chances of a cannon being able to catch missiles within their range before they strike (another ship, not talking about final fire here) are almost impossible unless you put them on an escort ship that stands at a reasonable distance away from the primary target. Many anti-ship missiles have a speed of between 20k-40k and will pass through the diameter of a 40k gauss equipped escort in more than 50% of the cases in the 5 second rounds. You might be lucky and have your escort driving in the same direction as the missile and increase the chances to fire, but that require allot of effort to attain.

yeah, gaussguns have a pitiful range. Stationing them before as and advance point before the fleet is entirely pointless. They are guranteed to get a shot in final-fire, while there is a less-than-100%-chance that enemy missiles end their 5s turn in range of an advance picket.

On the other hand i believe a lot of this applies to laser defences at well. Its incredibly costly to get lasers to shot at and advance range (16HS firecontroll plus large-diameter turreted laser...), while the hitchances drop down rather steeply. For the same costs it is usually possible to buy multiple shots against incoming missiles closed to the fleet.

to the fleet means tha

[Jorgen_CAB (OP)]

Well I did a little app to test my thesis.


If I have the following scenario...

Crew grade: 15%
Tracking bonus: 30%
Missile speed: 20k
FC tracking speed: 20k
Base to hit ratio: 86%

Full size quad gauss turret (12 shots)
Final to hit chance: 128%

Missile salvo 6: 12 kills on average
Missile salvo 12: 12 kills on average
Missile salve 18: 12 kills on average
Missile salvo 24: 12 kills on average


Two half size quad gauss turrets (24 shots)
Final to hit chance: 64.3%

Missile salvo 6: 6 kills on average
Missile salvo 12: 12 kills on average
Missile salve 18: 15.2 kills on average
Missile salvo 24: 15.3 kills on average


Crew grade: 15%
Tracking bonus: 30%
Missile speed: 30k
FC tracking speed: 20k
Base to hit ratio: 86%

Full size quad gauss turret (12 shots)
Final to hit chance: 85.7%

Missile salvo 6: 5.99 kills on average
Missile salvo 12: 10.2 kills on average
Missile salve 18: 10.2 kills on average
Missile salvo 24: 10.2 kills on average


Two half size quad gauss turrets (24 shots)
Final to hit chance: 42.8%

Missile salvo 6: 5.96 kills on average
Missile salvo 12: 9.8 kills on average
Missile salve 18: 10.1 kills on average
Missile salvo 24: 10.1 kills on average


It is only with very low number of shots you get a widespread results, such as...

Crew grade: 15%
Tracking bonus: 30%
Missile speed: 30k
FC tracking speed: 20k
Base to hit ratio: 86%

Full size quad gauss turret (2 shots)
Final to hit chance: 85.7%

Missile salvo 1: 0.98 kills on average
Missile salvo 2: 1.7 kills on average
Missile salve 4: 1.7 kills on average



Two half size quad gauss turrets (4 shots)
Final to hit chance: 42.8%

Missile salvo 1: 0.88 kills on average
Missile salvo 2: 1.44 kills on average
Missile salve 4: 1.68 kills on average


Unless I have seriously misunderstood how it work I fail to see how using a smaller gun is less advantageous or my app is doing something very wrong.