Poll: Favoured technology for beam point defence.

[sneer]

late game ASM can hit 100km/s easily
meanwhile you can push speed of ships to around 20km/s
non turreted weapon for PD is waste of time and effort in such scenario

I had 140km/s 26 wh str size 5 asm in use around 2110 year with conventional start

[Erik L]

If I can't put it in a turret, it's not PD.

And CWIS is good for all ships, but only for the ship it's on. There's going to be leakers through your escorts, so the CIWS will hopefully clean those up.

[Iranon]

Maybe it's my relatively lack of experience with high-end tech... but this doesn't make sense to me.

Railguns should outperform the other non-gauss options. At worst: 4 times the volume of fire, 1/4 the tracking speed, with smaller fire controls and no need for bulky turret gear - still ahead.
And such a direct comparison would hint at incompetent design of a turretless ship, we should probably shift tonnage from weapons to engines increasing effective firepower.

I get that high-tech missiles are harder to shoot down for equal tech beam PD ships - FC, ship and turret speed scale more or less linearly with tech, missile speed more so because we'll make full use out of increased power multipliers while we'll hold back for ships (too thirsty).
Thing is, this should affect all beam tech equally.  Yes, a low hit chance looks disconcerting... but what we should care about is expected number of hits.

As for PDs... I can understand it on something that's designed to operate alone, or a big fat target that we expect to get picked over other ships in the same location. Otherwise I see little point in a slightly more efficient point defence that will do nothing most of the time. "It'll take care of leakers" doesn't count if we could prevent leakers in the first place on the same budget.

Sorry if this seems confrontational... if I'm missing something I'd be thankful for being set straight.

[TheDeadlyShoe]

With probability, against missiles at your tracking speed or faster, 4x unturreted shots aren't as good.  4 shots at 25% to-hit gives you about a 30% chance to have a leaker, wheras one shot at 100% to-hit is a guaranteed hit.  Railguns do better relatively against faster and slower missiles, and on elite ships. 

I generally write off the anti-ship capability of point defense weapons, the range is just too short to be competitive unless you have a big advantage of speed and/or tech. When I do use railguns I generally use only smallest railgun whose range i can stomach in a ship-to-ship fight as the escort-type weapon.

To me the big advantage of CIWS is that it always works. Missile defense sensor destroyed? CIWS works.  Just went through a jump? CIWS works.  Point blank missile fire? CIWS works.  It's also a pretty nominal investment research wise, you just need 11,000 RP to get the Gauss ROF 3 tech.

P.S. Missiles gaining speed faster than beams gain tracking speed is why the tracking bonus techs exist.  I'm not sure if it mathematically cancels out, but it does ameliorate the problem. 

P.P.S I do note that a 10CM railgun with launch velocity 1 and capacitor 1 has the hilariously low cost of 1, so it has great potential mounted as a PDC or orbital defense weapon en masse. I've usually used particle beams for that as anti-ship weapons, but the missile defense value of such a station would be hilarious.

[Erik L]

I'd also have to say that my answer to this is conditional.

I normally pick a couple of tech lines for weapons. A major one and a couple minor. This is usually a random choice. So I may end up with a major choice for plasma carronades, and minors in laser and missiles.

This means my point defense is going to be lasers.

I also don't allocate RP to the other tech lines until I encounter them via NPR or ruins.

[Iranon]

@ TheDeadlyShoe:

I get the probability behind that.
I know turrets can be ahead,  but considering the overhead of turret gear and larger fire controls, we'd need a rather specific volume of incoming missiles at a rather specific speed range. Likewise, the reverse where turrets do worse than usual (high volume of fire, excessive tracking speed) should be rare against a competent opponent... but I've seen a few things from NPRs that made me scratch my head

On railgun calibre: I agree that 10cm railguns are generally the most useful ones. Larger often don't compare favourably to small lasers unless we have impressive capacitor tech.
In fact, I stick to 10cm railguns more than you do. For a limited anti-ship capability, I don't increase railgun size, I add limited laser armament.
if our speed and fire control irange s better than theirs, a single 15cm laser can give us flawless victories. If we take turn fire: 10cm railguns become much more useful in a knife fight if something else carves nice gashes. I don't discount them in the anti-ship role, but prefer not to have to use them that way.

On CIWS: If combat damage and losing crucial systems is a consideration, I'd rather add redundant sensors/FCs than CIWS and still risk losing most of my point defence.
Fortunately, low-tracking high-volume weapons makes FC redundancy cheaper as well.
That said, regular PD not working at point blank range (in final fire mode) and CIWS working during jump blindness were news to me, thanks for pointing that out.

@ Erik Luken:
Of course, RP considerations trump everyting else. I tend more towards picking a weird doctrine, then min/maxing ruthlessly in its implentation... but having certain lines of tech dormant until you discover them in foreign designs sounds interesting.

[Erik L]

@ Erik Luken:
Of course, RP considerations trump everyting else. I tend more towards picking a weird doctrine, then min/maxing ruthlessly in its implentation... but having certain lines of tech dormant until you discover them in foreign designs sounds interesting.

Of course, if the observed tech for example is a 10cm laser and I'm on 20cm gauss, I may not pick up the laser line because its perceived example is less than my tech

[sneer]

early in the game when low tech rails face low tech missiles ( especialy power factor ) rails may be ok
but in a moment your speed power factor is max the gap between turreted and non turreted PD widens fast with tech progression
there are situations ( not only hipotetical - I faced them in game few times ) where even max tech turreted gausses have problems
railguns would be overcome much faster
I have no time now and have no game left in saves to compare tech 5 railguns
but lets compare quad r5 gauss turret with 50km tracking tech + 60% bonus tech ( 25-30hs aprox)  on 15km/s ship and  similar tech rails within same mass vs 100 100km/s salvo
and we will have winner

[CharonJr]

For such a test the overall weight/cost should be equal I think, because personally I doubt I would use a gauss platform with the same speed as it would be needed for railguns.

[CharonJr]

Just fooled around a bit with some designs (fairly high-tech), but even then a 15km/s railgun-ship with enough weapons to have the slightest chance to serve as PD needs tons of engines:

Code: [Select]

Railgun PD class Cruiser    15 000 tons     533 Crew     6050 BP      TCS 300  TH 2250  EM 0
15000 km/s     Armour 5-54     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 6     PPV 81
Maint Life 2.18 Years     MSP 1512    AFR 300%    IFR 4.2%    1YR 427    5YR 6412    Max Repair 281 MSP
Intended Deployment Time: 12 months    Spare Berths 2   

300 EP Internal Fusion Drive (15)    Power 300    Fuel Use 74.4%    Signature 150    Exp 15%
Fuel Capacity 485 000 Litres    Range 7.8 billion km   (6 days at full power)

10cm Railgun V9/C3 (27x4)    Range 75 000km     TS: 15000 km/s     Power 3-3     RM 9    ROF 5        1 1 1 1 1 1 1 0 0 0
Fire Control S01 37.5-50000 (1)    Max Range: 75 000 km   TS: 50000 km/s     87 73 60 47 33 20 7 0 0 0
Inertial Confinement Fusion Reactor Technology PB-1 (3)     Total Power Output 3.6    Armour 0    Exp 5%
Inertial Confinement Fusion Reactor Technology PB-1 (3)     Total Power Output 18    Armour 0    Exp 5%
Inertial Confinement Fusion Reactor 60 PB-1 (1)     Total Power Output 60    Armour 0    Exp 5%

Active Search Sensor MR57-R1 (1)     GPS 240     Range 57.6m km    MCR 6.3m km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes


The gauss-ship looks much better IMO:

Code: [Select]

Gauss PD class Cruiser    15 000 tons     382 Crew     4215 BP      TCS 300  TH 750  EM 0
5000 km/s     Armour 5-54     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 6     PPV 195.84
Maint Life 1.1 Years     MSP 1054    AFR 300%    IFR 4.2%    1YR 876    5YR 13144    Max Repair 331 MSP
Intended Deployment Time: 12 months    Spare Berths 0   

300 EP Internal Fusion Drive (5)    Power 300    Fuel Use 74.4%    Signature 150    Exp 15%
Fuel Capacity 425 000 Litres    Range 6.9 billion km   (15 days at full power)

Quad Gauss Cannon R6-100 Turret 50k (6x24)    Range 60 000km     TS: 50000 km/s     Power 0-0     RM 6    ROF 5        1 1 1 1 1 1 0 0 0 0
Fire Control S01 37.5-50000 (1)    Max Range: 75 000 km   TS: 50000 km/s     87 73 60 47 33 20 7 0 0 0

Active Search Sensor MR57-R1 (1)     GPS 240     Range 57.6m km    MCR 6.3m km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes


Roughly same weigth of fire with much superior tracking. Even a slow railgun-ship looks better than the faster design:

Code: [Select]

Railgun PD 5k class Cruiser    15 000 tons     650 Crew     5252 BP      TCS 300  TH 750  EM 0
5000 km/s     Armour 5-54     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 3     PPV 171
Maint Life 1.19 Years     MSP 656    AFR 600%    IFR 8.3%    1YR 475    5YR 7129    Max Repair 240 MSP
Intended Deployment Time: 12 months    Spare Berths 0   

300 EP Internal Fusion Drive (5)    Power 300    Fuel Use 74.4%    Signature 150    Exp 15%
Fuel Capacity 535 000 Litres    Range 8.6 billion km   (19 days at full power)

10cm Railgun V9/C3 (57x4)    Range 75 000km     TS: 12500 km/s     Power 3-3     RM 9    ROF 5        1 1 1 1 1 1 1 0 0 0
Fire Control S00.2 37.5-12500 (1)    Max Range: 75 000 km   TS: 12500 km/s     87 73 60 47 33 20 7 0 0 0
Inertial Confinement Fusion Reactor Technology PB-1 (8)     Total Power Output 48    Armour 0    Exp 5%
Inertial Confinement Fusion Reactor Technology PB-1 (3)     Total Power Output 3.6    Armour 0    Exp 5%
Inertial Confinement Fusion Reactor 60 PB-1 (2)     Total Power Output 120    Armour 0    Exp 5%

Active Search Sensor MR57-R1 (1)     GPS 240     Range 57.6m km    MCR 6.3m km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes

Twice the guns for a bit less tracking speed.

But even without running any tests I can not see many high-tech battles were the rails look superior to me. Starting at 30km/s missile speed the gauss should be better.

[Iranon]

Are you seriously comparing these with 250000RP Gauss, Turret and and Fire Control techs and 40000RP engine tech? Of course that's not going to work out for railguns.
Even "balanced tech" is flattering for the Gauss ship, because someone focusing on railguns for PD may skip Gauss and Turret technology entirely and spend it on engines... which has all sorts of other benefits, wherever high speed isn't needed we save fuel.

[CharonJr]

Kept even below the levels the Sneer suggested, but yes, the tech cost for the gauss are way higher. 3 techs needed for gauss turret vs. 1 for rails.

A more appropriate test might be a fixed TP (e.g. 1 million TP) for the complete design, thus the rail-ship should have better engines and targeting. But I think that at a certain level the gauss will still be better.

[CharonJr]

K, time for a more realistic test.

1st test with 300k TP, ships have to have 5 armor, a range of 20bkm and a deployment time of 1 year as basic
parameters (and the engines have to be size 10, multiplier of 1.0, active sensors are identical).

Gauss:

Code: [Select]

Tribal class Cruiser    18 150 tons     357 Crew     2823.5 BP      TCS 363  TH 1440  EM 0
3966 km/s     Armour 5-61     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 7     PPV 153.75
Maint Life 1.15 Years     MSP 681    AFR 376%    IFR 5.2%    1YR 526    5YR 7895    Max Repair 226 MSP
Intended Deployment Time: 12 months    Spare Berths 1   

160 EP Magneto-plasma Drive (9)    Power 160    Fuel Use 72%    Signature 160    Exp 10%
Fuel Capacity 1 450 000 Litres    Range 20.0 billion km   (58 days at full power)

Quad Gauss Cannon R3-100 Turret (5x16)    Range 30 000km     TS: 25000 km/s     Power 0-0     RM 3    ROF 5     

  1 1 1 0 0 0 0 0 0 0
Fire Control S02 24-25000 (1)    Max Range: 48 000 km   TS: 25000 km/s     79 58 38 17 0 0 0 0 0 0

Active Search Sensor MR5-R1 (1)     GPS 42     Range 5.9m km    MCR 640k km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes

Lets see what we can get with a similar BP using rails.

Code: [Select]

Tribal class Cruiser    15 250 tons     385 Crew     2857.6 BP      TCS 305  TH 3200  EM 0
10491 km/s     Armour 5-54     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 4     PPV 60
Maint Life 1.27 Years     MSP 468    AFR 465%    IFR 6.5%    1YR 305    5YR 4576    Max Repair 100 MSP
Intended Deployment Time: 12 months    Spare Berths 1   

200 EP Internal Fusion Drive (16)    Power 200    Fuel Use 54%    Signature 200    Exp 10%
Fuel Capacity 950 000 Litres    Range 20.8 billion km   (22 days at full power)

10cm Railgun V3/C3 (20x4)    Range 30 000km     TS: 10491 km/s     Power 3-3     RM 3    ROF 5        1 1 1 0 0

0 0 0 0 0
Fire Control S01 24-12500 (1)    Max Range: 48 000 km   TS: 12500 km/s     79 58 38 17 0 0 0 0 0 0
Magnetic Confinement Fusion Reactor Technology PB-1 (6)     Total Power Output 60    Armour 0    Exp 5%

Active Search Sensor MR5-R1 (1)     GPS 42     Range 5.9m km    MCR 640k km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes

The gauss is still better, even at equal tech/BP levels, the only disadvantage is the gauss needing a 20% larger shipyard. But since my TP usage might have been less than optimal for the railguns (too much emphasis on FC) lets add another level of engine tech (80k TP).

Code: [Select]

Tribal Mk2 class Cruiser    13 350 tons     350 Crew     2803.4 BP      TCS 267  TH 3250  EM 0
12172 km/s     Armour 5-50     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 3     PPV 60
Maint Life 1.04 Years     MSP 394    AFR 475%    IFR 6.6%    1YR 366    5YR 5491    Max Repair 125 MSP
Intended Deployment Time: 12 months    Spare Berths 1   

250 EP Magnetic Fusion Drive (13)    Power 250    Fuel Use 54%    Signature 250    Exp 10%
Fuel Capacity 800 000 Litres    Range 20.0 billion km   (18 days at full power)

10cm Railgun V3/C3 (20x4)    Range 30 000km     TS: 12172 km/s     Power 3-3     RM 3    ROF 5        1 1 1 0 0 0 0 0 0 0
Fire Control S01 24-12500 (1)    Max Range: 48 000 km   TS: 12500 km/s     79 58 38 17 0 0 0 0 0 0
Magnetic Confinement Fusion Reactor Technology PB-1 (6)     Total Power Output 60    Armour 0    Exp 5%

Active Search Sensor MR5-R1 (1)     GPS 42     Range 5.9m km    MCR 640k km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes

Another 2kt lighter, but still fairly slow. And as the final test - if BP is not the restriction, but shipyard size is - roughly the same size as the original gauss-ship (while keeping the MFC engines for the rail).

Code: [Select]

Tribal Mk3 class Cruiser    18 200 tons     503 Crew     3765 BP      TCS 364  TH 4250  EM 0
11675 km/s     Armour 5-61     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 4     PPV 93
Maint Life 1.03 Years     MSP 517    AFR 662%    IFR 9.2%    1YR 487    5YR 7301    Max Repair 125 MSP
Intended Deployment Time: 12 months    Spare Berths 1   

250 EP Magnetic Fusion Drive (17)    Power 250    Fuel Use 54%    Signature 250    Exp 10%
Fuel Capacity 1 100 000 Litres    Range 20.1 billion km   (19 days at full power)

10cm Railgun V3/C3 (31x4)    Range 30 000km     TS: 11675 km/s     Power 3-3     RM 3    ROF 5        1 1 1 0 0 0 0 0 0 0
Fire Control S01 24-12500 (1)    Max Range: 48 000 km   TS: 12500 km/s     79 58 38 17 0 0 0 0 0 0
Magnetic Confinement Fusion Reactor Technology PB-1 (9)     Total Power Output 90    Armour 0    Exp 5%
Magnetic Confinement Fusion Reactor Technology PB-1 (3)     Total Power Output 3    Armour 0    Exp 5%

Active Search Sensor MR5-R1 (1)     GPS 42     Range 5.9m km    MCR 640k km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes

For a roughly the same performance as the gauss-ship the rail would need at least another 10 guns, so it looks like at 300k TP for ship systems the gauss is already ahead of the rails. But the rail-ship itself will be harder to hit due to its better speed.

If the armor is removed for additonal guns we get fairly close to the gauss-ship, with gauss still being slightly better and the rail-ship a bit heavier.

Code: [Select]

Tribal Mk4 class Cruiser    18 350 tons     587 Crew     3773.6 BP      TCS 367  TH 4250  EM 0
11580 km/s     Armour 1-61     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 4     PPV 120
Maint Life 1.05 Years     MSP 514    AFR 673%    IFR 9.4%    1YR 464    5YR 6965    Max Repair 125 MSP
Intended Deployment Time: 12 months    Spare Berths 2   

250 EP Magnetic Fusion Drive (17)    Power 250    Fuel Use 54%    Signature 250    Exp 10%
Fuel Capacity 1 100 000 Litres    Range 20.0 billion km   (19 days at full power)

10cm Railgun V3/C3 (40x4)    Range 30 000km     TS: 11580 km/s     Power 3-3     RM 3    ROF 5        1 1 1 0 0 0 0 0 0 0
Fire Control S01 24-12500 (1)    Max Range: 48 000 km   TS: 12500 km/s     79 58 38 17 0 0 0 0 0 0
Magnetic Confinement Fusion Reactor Technology PB-1 (12)     Total Power Output 120    Armour 0    Exp 5%

Active Search Sensor MR5-R1 (1)     GPS 42     Range 5.9m km    MCR 640k km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes


[MarcAFK]

How does the difference in tracking speed actually compare? It would be interesting to see what the theoretical kill ratio of each of those designs would be against missiles of various speeds.

[sneer]

we would need a cross table vs diffrent misile speeds
I'm unfortunately too busy this weekend ... maybe in a few days I;d go for it