Gauss point defense ships

[Arwyn (OP)]

So, I have decided that I REALLY like gauss point defense ships. I have used lasers and mesons in the past (and railguns) but I wound up with pretty good Gauss tech in my current game, good railguns, poor laser tech, and no meson tech outside of the starting 10cm. So, I ran with it and equipped my close PD ships with triple Gauss turrets.

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Griffin Mk II class Escort    10,550 tons     786 Crew     1889 BP      TCS 211  TH 810  EM 600
5118 km/s     Armour 5-42     Shields 20-300     Sensors 8/8/0/0     Damage Control Rating 14     PPV 58.2
Maint Life 1.81 Years     MSP 448    AFR 222%    IFR 3.1%    1YR 171    5YR 2561    Max Repair 164 MSP

Applied Dynamics Ion Engine E800 (18)    Power 60    Fuel Use 80%    Signature 45    Armour 0    Exp 5%
Fuel Capacity 350,000 Litres    Range 74.6 billion km   (168 days at full power)
Gamma R300/14 Shields (10)   Total Fuel Cost  140 Litres per day

Triple Open Gauss R3-100 Turret (2x9)    Range 30,000km     TS: 20000 km/s     Power 0-0     RM 3    ROF 5        1 1 1 0 0 0 0 0 0 0
Teksystems Defender Turret Fire Control (2)    Max Range: 96,000 km   TS: 20000 km/s     90 79 69 58 48 38 27 17 6 0

Teksystems Skyband 15/50 Search Sensor (1)     GPS 1400     Range 15.8m km    Resolution 50
Defense Tech Bulwark AMM Sensor (1)     GPS 56     Range 4.5m km    Resolution 1
Thermal Sensor TH1-8 (1)     Sensitivity 8     Detect Sig Strength 1000:  8m km
EM Detection Sensor EM1-8 (1)     Sensitivity 8     Detect Sig Strength 1000:  8m km
Yes, I know the gas and the maint is light, done deliberately, these operate with a fleet with dedicated fleet trains. And yes, I know the sensors are seriously overbuilt. Done by design.

The AMM sensor gives me more time to track inbounds, which gives a nice bonus to tracking speed, which I NEED with how fast the enemy inbounds are.

Fire control is overbuilt to give the best possible hit percentage against targets at engagement ranges

Overall, I am pretty impressed with how well these little guys actually work. With good crew training, I was seeing 5 to 7 missiles intercepted by these ships per salvo. With two of these, and a third ship with a single, the missiles that made it through the AMM fire got annihilated by the Gauss PD ships.

The extra bonus was finding out how nasty these things can be point blank. Bad guys jumped on top of us at a warp point, and while everything else was still powering up, these Gauss sawed through the enemy cruisers shields in 10 seconds of fire from both ships, and sandblasted the heck out of the armor.

I'm sold on em, I just wished the next rank of Gauss cannon velocity wasn't so expensive!

[TheDeadlyShoe]

Yeah, these kinds of ships are pretty great. ROF 5 just rips through things - though the message spam can be annoying. xD

* The thermal/EM sensors are unnecessary, particularly if you have stronger passives on another ship.
* Similarly, the Resolution 50 search sensor is unnecessary - it's not going to pick up any missiles, and your AMM sensor more than covers the range of your gauss weapons.
* If this is intended primarily as an escort you might be drastically over-engined. You don't really have the weapons range to be a secondary beam vessel IMO - Warp point defense is an important exception.  Unless your battle-line also runs around 5000 km/s, I would consider reducing the number of engines.  Speed is great, but all those engines are way driving up your cost (and therefore how much missile defense bang you're getting for your buck.)
*Shields are nice, but 20 points wont do a lot. If you dump the shields, the passives and the res50 sensor, you might have enough space to squeeze in another gauss turret. I'm not sure how big those things are, lol. 
*Bear in mind that engineering spaces also reduce the rate at which failures occur, reducing MSP consumption, and it costs resources/wealth to manufacture MSP.
*Your fuel levels are fine actually.  It only looks short because of the sheer number of engines the ship mounts Personally I rate ships by their range, not their days at full power. 75 billion km is more than the vast majority of my military ships.

[Arwyn (OP)]

I tend to run sensors on all the ships, partly for RP purposes, partly because I have had sensors shot away in the past and was annoyed by not having replacements.

As far as the engines and speed, the battle line runs at 5000 km/s. After several games, I run fast by choice. Not cheap, but the option of running away from most similar tech opponents (and some higher tech) is very handy.

I actually find the shields VERY handy. If the shields are taking hits, that's armor I don't have to repair later, and a ship that I don't have to take out of service for the repairs. I find that flexibility worth while, especially with ships strung out over the warp lines. If the do get shot up, I have some protection should they get engaged again.

Agree on the engineering spaces. The Mk III version of the ship is coming soon, which has a massively upgraded sensor suite, which frees up a lot of space. That will get filled with engineering.

As far as adding another turret, its on the plans. The biggest issue is the turrets themselves, size 29 in this ship. 20,000 km/s tracking is expensive in ship board real estate. The new versions are size 23.33 for the exact same turret, which frees up a lot of space and weight. The fire control is only size 4, and its the bottleneck, if I could get tracking up to 30,000 km/s, I would really be tearing up the opposing sides missiles....

[TheDeadlyShoe]

if you value speed so much, I suggest getting the -efficiency +power tech for engines... It reduces your durability a little, but with the amount of engines you are mounting it amounts to either decent tonnage savings or a nice leetle speed boost.

naturally, that would be for next generation ships, as refitting all those engines just for a minor upgrade would be hella expensive.

[Charlie Beeler]

In my not so humble opinion Arwyn you've got a good start here.

I'd drop the res 50 active and add that tonnage to the res 1.  The res 1 already sees everything that the res 50 does and at a greater range once you up the size.

Dump the passive sensors on the escort.  they're taking up tonnage that you need elsewhere and giving you nothing back that's useful. 

Drop the armor to 3 layers and double the shields.  unlike armor, shields are realatively cheap to upgrade later.  40 points of shield function as a full layer of armor that must be completely removed before anything else takes damage.  With the exception of microwave and meson of course.

Instead of adding engineering spaces look into damage control. 

If you don't have the space for a third turret and BFC try making the turrets quads. 

[Arwyn (OP)]

Here is the Mk III version;

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Griffin Mk III class Escort    10,800 tons     856 Crew     2174 BP      TCS 216  TH 378  EM 1200
5000 km/s     Armour 3-43     Shields 40-300     Sensors 1/1/0/0     Damage Control Rating 15     PPV 61.82
Maint Life 2.37 Years     MSP 629    AFR 186%    IFR 2.6%    1YR 153    5YR 2292    Max Repair 179 MSP

Applied Dynamics E850 Ion Engine (18)    Power 60    Fuel Use 60%    Signature 21    Armour 0    Exp 5%
Fuel Capacity 300,000 Litres    Range 83.3 billion km   (192 days at full power)
Gamma R300/14 Shields (20)   Total Fuel Cost  280 Litres per day

Phalanx Quad Gauss Turret (2x12)    Range 30,000km     TS: 20000 km/s     Power 0-0     RM 3    ROF 5        1 1 1 0 0 0 0 0 0 0
Teksystems Defender Turret Fire Control (2)    Max Range: 96,000 km   TS: 20000 km/s     90 79 69 58 48 38 27 17 6 0

Defense Tech Bulwark AMM Sensor (1)     GPS 56     Range 4.5m km    Resolution 1
Shaved weight by bumping fuel down, but with the more efficient engines, range is the same. Speed is a bit less, as is the armor. Shields are doubled, dropped the passive sensors.

Biggest change is that the new versions of the turrets, and the weight saved let me install quad Gauss turrets instead of triples.

[Theokrat]

Hm, what is you tech level on turret tracking speed and beam FC tracking speed? Depending on these values Railguns can sometimes be a better choice than gauss

[Charlie Beeler]

Hm, what is you tech level on turret tracking speed and beam FC tracking speed? Depending on these values Railguns can sometimes be a better choice than gauss

Based on his designs it looks like is BFC speed is 5000kps since the example BFC should be a 4x speed installation.  That limits railguns to a tracking speed of 5000kps since they may not be turret mounted.  Even with the ability to mount roughly twice as many RG's, assuming 10cm, that have 1 more chance to hit on 1v1 mount comparison is not enough to overcome the 4x greater tohit penalty against targets that are faster than the tracking speed. 

Keep in mind that doubling of mounts for RG's does not take into account the need for powerplants to feed the RG's.

[Theokrat]

Based on his designs it looks like is BFC speed is 5000kps since the example BFC should be a 4x speed installation.  That limits railguns to a tracking speed of 5000kps since they may not be turret mounted.  Even with the ability to mount roughly twice as many RG's, assuming 10cm, that have 1 more chance to hit on 1v1 mount comparison is not enough to overcome the 4x greater tohit penalty against targets that are faster than the tracking speed. 

Keep in mind that doubling of mounts for RG's does not take into account the need for powerplants to feed the RG's.

Keep in mind that each railgun shoots 4 projectiles though. Lets go through the math:

The proposed design hosts 2 Quad Turrets for a total of 8 Gaussguns. A Gaussgun is 6 HS so the weapons itself must weigh 48 HS. Assuming a turret gearing speed of 5,000 kps, the mounting in turrets will add 36% to the weapons weight, so we get a total of 65 HS for the weapons. If the BFC tracking speed is 5,000 kps, the base range might be 48k (one tech level higher, I actually would expect something like 24k), hence the two firecontrolls would have a size of 8 HS each, a total of 16HS. So overall the whole weapon system would likely weigh about 81 HS = 4,050t.

As you say, railguns can not be turret mounted, and thus would be limited to a tracking speed of 5,000 kps anyway. The Firecontrolls at that level would weigh only 2 HS each, or 4 HS for two of these. That leaves 77 HS for weapon systems. A basic railgun is 3 HS, and requires 3 Energy. At Ion technology a 2HS reactor can provide 9 Energy. So 3 railguns would occupy 11 HS. Thus for 77 HS we could have 33 (powered) railguns.
Now how do the two systems compare?

• The 8 Gaussguns launch 3 projectiles each, or a total of 24 projectiles every five seconds. Against missiles moving 40,000 km/s they would have a probability of 50%, meaning we can expect do down 12 incoming missiles every turn by Gaussguns.
  
• The 33 Railguns each launch 4 projectiles, totalling 132 projectiles. They would only have a hit chance of 12.5%, as they would only have tracking speed of 5,000 km/s. That still leads to 16.5 incoming missiles being shot down every turn by railguns.

Thus the Railguns are expected to shoot down 37.5% more missiles than the Gaussguns at equal weight. Note that this is derived under conservative assumptions. If the firecontrolls used in the example were (4xrange, 4x size), then they would weigh a total of 32 HS for the gaussguns, while only 8 HS for railguns – a difference of 24 HS, rather than 12 as assumed (i.e. 3 more railguns in that scenario).

[TheDeadlyShoe]

^^ Above math and similar comparisons is why I abandoned gauss cannons for railguns, even leaving aside the superior antiship potential of railgun technology.  Gauss cannons do not become superior to 10cm railguns at point defence until you get 4x shots (~magnetoplasmic tech). 10cm railguns are also significantly less research intensive in every respect.   On the other hand, gauss cannons can be scaled down to fit in fighters and also give you CIWS systems - though both CIWS and gauss fighters are of questionable value.

also, having 132 damage messages in the log is frigging ridiculous. screw that.

[Charlie Beeler]

Keep in mind that each railgun shoots 4 projectiles though. Lets go through the math:

The proposed design hosts 2 Quad Turrets for a total of 8 Gaussguns. A Gaussgun is 6 HS so the weapons itself must weigh 48 HS. Assuming a turret gearing speed of 5,000 kps, the mounting in turrets will add 36% to the weapons weight, so we get a total of 65 HS for the weapons. If the BFC tracking speed is 5,000 kps, the base range might be 48k (one tech level higher, I actually would expect something like 24k), hence the two firecontrolls would have a size of 8 HS each, a total of 16HS. So overall the whole weapon system would likely weigh about 81 HS = 4,050t.

As you say, railguns can not be turret mounted, and thus would be limited to a tracking speed of 5,000 kps anyway. The Firecontrolls at that level would weigh only 2 HS each, or 4 HS for two of these. That leaves 77 HS for weapon systems. A basic railgun is 3 HS, and requires 3 Energy. At Ion technology a 2HS reactor can provide 9 Energy. So 3 railguns would occupy 11 HS. Thus for 77 HS we could have 33 (powered) railguns.
Now how do the two systems compare?

• The 8 Gaussguns launch 3 projectiles each, or a total of 24 projectiles every five seconds. Against missiles moving 40,000 km/s they would have a probability of 50%, meaning we can expect do down 12 incoming missiles every turn by Gaussguns.
  
• The 33 Railguns each launch 4 projectiles, totalling 132 projectiles. They would only have a hit chance of 12.5%, as they would only have tracking speed of 5,000 km/s. That still leads to 16.5 incoming missiles being shot down every turn by railguns.

Thus the Railguns are expected to shoot down 37.5% more missiles than the Gaussguns at equal weight. Note that this is derived under conservative assumptions. If the firecontrolls used in the example were (4xrange, 4x size), then they would weigh a total of 32 HS for the gaussguns, while only 8 HS for railguns – a difference of 24 HS, rather than 12 as assumed (i.e. 3 more railguns in that scenario).

Great math, but your base numbers are wrong. 

Granted the GC turrets are 32.64hs each but the BFC's are only 4hs.  Most get the BFC wrong at first.  You got that the base BFC range tech is 48k, but that is for a 50% tohit change with a max range of 96k as shown.  To get the tracking speed of 20k the BFC is only 4x on speed and standard on range.  This gives 73.28hs for the BFC's and turrets.

Since the Railguns require neither a range modifier nor speed modifier they only need standard sz 1 BFC's.  That leave us with 71.28hs to play with.  Playing with reactor sizes your only going to get 19 powered railguns into that space not 33 giving only 76 shots not 132. 

You've also got the hit chances wrong.  The 50% and 12.5% are only the penalty for the tracking speed being to slow.  This still needs to be applied to the base 90% of the fire control at 10k/km assuming final defensive fire.  That gives 45% per shot for the GC Turrets and 11.25% for the RG's.  Which results in a probable 10.8 intercepts for the turrets and 8.55 for the RG's.

Once GC's reach 3 shots each they out perform the RG's on an equal hs basis for per missile intercept.  The RG's installation would have a more flexability in that the lighter support BFC means that you could design to engage a greater number of salvos than the GC's can.

[Theokrat]

Great math, but your base numbers are wrong. 

Granted the GC turrets are 32.64hs each but the BFC's are only 4hs.  Most get the BFC wrong at first.  You got that the base BFC range tech is 48k, but that is for a 50% tohit change with a max range of 96k as shown.  To get the tracking speed of 20k the BFC is only 4x on speed and standard on range.  This gives 73.28hs for the BFC's and turrets.

Since the Railguns require neither a range modifier nor speed modifier they only need standard sz 1 BFC's.  That leave us with 71.28hs to play with.  Playing with reactor sizes your only going to get 19 powered railguns into that space not 33 giving only 76 shots not 132. 

You've also got the hit chances wrong.  The 50% and 12.5% are only the penalty for the tracking speed being to slow.  This still needs to be applied to the base 90% of the fire control at 10k/km assuming final defensive fire.  That gives 45% per shot for the GC Turrets and 11.25% for the RG's.  Which results in a probable 10.8 intercepts for the turrets and 8.55 for the RG's.

Once GC's reach 3 shots each they out perform the RG's on an equal hs basis for per missile intercept.  The RG's installation would have a more flexability in that the lighter support BFC means that you could design to engage a greater number of salvos than the GC's can.

Eh, I made a more basic error even. If we have 77 HS, and get 3 railguns per 11 HS, then of course get 21 Railguns, not 33 in the first place. So yeah, the gauss would be somewhat better under my original assumption.

Nevertheless depending on the BFC base tech it might still be better - it depends on what range multiplier he used. We do not know that he did indeed choose 1xrange, 1xsize (although I concede that based on some back-of the envelope math that would likely be the best use of hullspace, given the quickly diminishing returns of additional FC range for PD).

I deliberately ignored the hit chance modification due to the range, as it applies to both railguns and gauss guns, and therefore is irrelevant for a comparison of the two. You would also need to factor in grade modifiers and ECM to get the actual hit chances.

[Arwyn (OP)]

I have used 10cm railguns for anti-missile duty early on in the game. Early on, they worked great. As tech picked up, and against some of the Precursors, they dont do nearly as well as the speeds increase.

Right now, I have the quad Gauss turrets tracking at 20,000 km/s, along with the fire controls. Fire controls space is size 4, so with the turret included, each turret + fire con package comes in at 34.91 in terms of space.

I focused on the speed portion due to the high speed of some of the missiles I am facing, most are running 24,800 km/s but I have a system full of annoying robots with "Axepunisher" anti-ship missiles running 38,200 km/s.

Against the latter, the railguns don't do much of anything. The Gauss turrets, with the higher tracking, have a much better chance to hit.

[Charlie Beeler]

Actually since he posted the design we can make several deductions.  

We know for example that the ship is 216hs has 18 engines, 20 shields, 6 fuel tanks, and 2 quad GC turrets.  All of these have fixed usage of 181.28hs leaving 34.72hs.

We also know that the active sensor has a gps of 56 resolution of 1 and max range for that resolution of 4.5m km and that there is only 1.  Odds are good that the tech levels are 21 active grav sensor and 11 for EM sensor which would give a sz 2 suite.  

Since the crew size is 2174 there is probably 9 full size (1hs) crew quarters.

The maintenance supply points are fairly low so there is most likely only 2 or 3 hs devoted here.

I made an induction that the armor tech would need to be at least ceramic Composite to have enough hs left for 2 size 4 BFC's with 3 layers of armor.  And the only way for that to match the stats posted is for Beam range tech to be 48k for 50% and beam tracking at 5k kps.

I deliberately don't ignore the BFC hit chance since it is a known factor that will not change.  Crew grade and ECM are intangibles and can be left out of the analysis.

[Arwyn (OP)]

Currently the design has the following;

2x Phalanx Quad Gauss Cannon Turrets (61.82 HS)
2x Teksystems Defender Turret Fire Control (8 HS)

20x Gamma R300/14 Shields (20 HS)
13x Ceramic Composite Armor
1x Damage Control (3 HS)

18x Applied Dynamics E850 Ion Engines (90 HS)

1x Defense Tech Bulwark Mk2 AMM Sensor (2 HS)

3x Crew Quarters (3 HS)
2x Crew Quarters (small) (.4 HS)
6x Fuel Storage (6 HS)
5x Engineering spaces (5 HS)
1x Bridge (1 HS)

There was a change to the design posted above, after I posted I caught that I had too many crew quarters and reduced them. Ship went down 100 tons and crew went from 856 to 847.