Poll: Favoured technology for beam point defence.

[sneer]

OK
I did at least half of job so I start summery ( this post will be modified so it is a part so far )

assumtpions
PD is part of bigger ship not a dedicated PD ship
I carve out enough space to put FC+ 2 quad gauss turrets and compare to similar space using railgun setup
it is worth mentioning while gausess increases rof , railguns hits max for in tier 3 tech in 10cm v3/ c3 with 4 shots per gun
it is worth mentioning that it is difficult to calculate total cost for rail system as plant costs are usually neglected as needed for engines
it is worth noting that increasing plant efficiency allows to mount more railguns pre tech level 
ships could be made a bit faster but I assumed some typical average designs -ie 4km for magneto era ships
all ship speed fits adequate gun system level - it differs in game but i wanted  to do as equal conditions as possible
there is no diffrence in size of PD Fire control as gausses uses a bit bigger - you can add 1 more gun to railgun comparison if you want  ot cover it


techs
1.          gauss r-1 system 2quad = 8shots every 5 sec with 8km/s tracking
 eq       rail 10cm v1/c1 system can fit 15 guns so 60shots every 15 sec with ship speed = tracking at 1km/s tech
tech cost very similar

2.         gauss r -2 system 2 quad = 16 shots every 5 sec 12 km/s tracking
eq       rail 10cm v2/c2 can fit 16 guns with 64 hot every 10 sec  with ship speed = tracking at 2km/s

3.        gauss r-3 system 2quad = 24shots every 5 sec with 16km/s tracking
 eq       rail 10cm v3/c3 system can fit 17 guns so 68shots every 5 sec with ship speed = tracking at 3km/s tech (ion eng)

in this place railguns hits its maximum efficiency a they have 5 sec rof - no further tech can change number of shot or size of guns that is critical
till this place railguns are cheaper than gauss - however it is not budget ruining diffrence
things start getting interesting in megneto plasma era

4.    gauss r-3 system 2quad = 24shots every 5 sec with 16km/s tracking  - gaus stay with old design in this tech level as their jump is huge and next level guns fits by cost level 5 tech - so no new gauses but better tracking so 20km/s trasking on this level
 eq       rail 10cm v4/c4 system can fit 18 guns so 72shots every 5 sec with ship speed = tracking at 4km/s tech (magneto eng )

interesting situation , isn't it ?
railguns offers 3 times shots volume vs 1/5 tracking - all will depend on missile types  ( it should be diffrent analysis later )

5.     gauss r-4 system 2quad = 32 shots every 5 sec with 25km/s tracking 
 eq       rail 10cm v5/c5 system can fit 19-20 guns so 76-80shots every 5 sec with ship speed = tracking at 5km/s tech (early fusion tech )

at this point technology cost between gausses and railguns is pretty similar
railguns offer twice the volume for 1/5 tracking  - do you see the trend ?- it is because rails can not lower size or increase rof
from this point further analysis is pointless as gausses still have 2 rof upgrades ahead and relation on similar tech turrets to average ship speeds is like 4:1 so keep constant in terms of relative tracking and accurancy

of course you may go for faster ships when using railguns
so you can pump tracking possibly up to 30% for a cost of lower comparable efficiency somewhere else
10cm railguns are much better weapon when other then PD situation - sheer volume of shots guarantee this
but as a long term choice for PD - gausses are winner
I can only guess ( thinking of doing some calculations later) that non perfect in terms of power multiplier missile engines means that pre magneto / early fuzion you face relatively slow missiles so rails got advantage os some kind and later vs modern really fast missiles tracking will be a killing factor for this kind of PD



wall of text

I'd like to check how this tech level PD system would behave vs missiles of its era to check PD umbrella efficiency
but this will be another time

sorry for spelling - I had very limited time when running this and I'm not native

[CharonJr]

Played around a bit as well and got some data.

Essentially gauss (5 quad turrets) is better even than the somewhat pimped Tribal Mk4 (40 rails), except at low speeds due to Mk4s larger number of guns. The lower modifier can not be compensated by the higher number of projectiles/guns. And since the results look fairly linear to me it should be easy to calculate which is better for any combination.

In short: At half the gauss turrets tracking speed the railguns need double to volume of fire to compensate.

PS: Is there any way to display an attached image (except using an external service)?

edit: Ah, it does display the image

[sneer]

you did not show assumptions
what tech level ? ship speed ? etc
also 40 railgun uses aprox 5 quad turrets space  ( see my post above )
comparing to 20 is pointless

[CharonJr]

Those are the designs I posted earlier with 300k TP used on ship techs, Tribal gauss, Tribal rail, Tribal rail Mk4.

Those are pure PD designs, so the gauss gets away with overall fleet speed while fhe rails have to be much faster to get better to hit chances and due to it much higher BP needed for the Mk4.

If you use the same BP you will not be able to fit in more than 20 rails for comparable to hit chances.

[sneer]

BP doesn;t really matter unless you are stremlining production and building all the time
it is tonnage that is important to get maximum utility for your vessel

[CharonJr]

Yes, but fixed weight does not change anything about the results. E.g. 13x 10HS engine yields a speed of 8333 with 30 guns (79% Chance to hit at 12.5k at a speed of 8333 with 30 guns will cause 63.2 hits) while 40 guns with just 10 engines (speed of 6289) will cause 63.6hits at roughly the same weight (bit more actually due to addional reactors needed).

And when having to build a fleet as quickly as possible (e.g. found some unfriendly aliens) BP is important.

[sneer]

diffrent approach
when I have few designs that have multiple weapon system I have limited space in order to have same speed with same engines
that's why BP is at least secondary ( it is like having 2-4 triple to quad guass turrets as PD or mass equivalent )
also my shipyards stay idle for 60-70% time so BP cost is not important unless emergency
I rarely loose ships ( most time I frakk up I loose whole fleet - but it is rare)- use some light modernizations to keep them in line long enough and so on


Gauss are clear win for PD in middle to late game
Rails are win in early game and under favourable conditions can be good PD in middle game ( when you fight NPR instead of spoilers - as NPR missile ar far worse and often terribly slow - )

[CharonJr]

But there is a point when railguns will be better and this is when the tech based tracking speed is higher than the ship-speed based tracking Speed - whenever speed/engines are traded for rails at ship speeds below the tech based tracking speed the number of projectiles go up without the to hit chances going down:

Code: [Select]

Tribal class Cruiser    16 150 tons     576 Crew     2748.8 BP      TCS 323  TH 1400  EM 0
[b]4334 km/s[/b]     Armour 5-56     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 3     PPV 150
Maint Life 1.1 Years     MSP 319    AFR 695%    IFR 9.7%    1YR 265    5YR 3976    Max Repair 100 MSP
Intended Deployment Time: 12 months    Spare Berths 0   

200 EP Internal Fusion Drive (7)    Power 200    Fuel Use 54%    Signature 200    Exp 10%
Fuel Capacity 970 000 Litres    Range 20.0 billion km   (53 days at full power)

10cm Railgun V3/C3 (50x4)    Range 30 000km     [b]TS: 6250 km/s[/b]     Power 3-3     RM 3    ROF 5        1 1 1 0 0 0 0 0 0 0
Fire Control S00.5 24-6250 (1)    Max Range: 48 000 km   TS: 6250 km/s     79 58 38 17 0 0 0 0 0 0
Magnetic Confinement Fusion Reactor Technology PB-1 (15)     Total Power Output 150    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

But unless really slow ship speeds are used gauss should still be better, starting at around 25kkm/sec missile speed.

[sneer]

in this case no matter your tech tracking is what your ship speed is

[Iranon]

Railguns on slow ships are only competitive in th very early game.
3HS + power for 4 shots at basic speed doesn't compare well to ~8 HS for a 4x tracking speed Gauss barrel once we have Gauss RoF 3.
Going for 1.5 the basic FC speed often gives us more effective firepower on the same budget, even if we don't value speed in itself (if I wasn't valuing speed, I wouldn't favour Railguns though).

My own tests were a little more flattering to Railgun ships than CharonJr's:
Fast turretless beam ships are tight designs, they have little mission tonnage but get higher value out of it.
As such, anything we spec that costs weight (armour, sensors, small engines forcing us to carry more fuel, electronic warfare) hurts them a lot more than it hurts turreted Gauss ships. Same for any small inefficiencies like not hitting the idea FC speed.

Still, my numbers don't differ too much:

Code: [Select]

Flower-G class Destroyer Escort    9 100 tons     215 Crew     1363 BP      TCS 182  TH 720  EM 0
3956 km/s     Armour 4-38     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 4     PPV 92.73
Maint Life 1.07 Years     MSP 374    AFR 165%    IFR 2.3%    1YR 330    5YR 4948    Max Repair 324 MSP
Intended Deployment Time: 10 months    Spare Berths 0   

720 EP Magneto-plasma Drive (1)    Power 720    Fuel Use 23.05%    Signature 720    Exp 9%
Fuel Capacity 250 000 Litres    Range 21.5 billion km   (62 days at full power)

Quad Gauss Cannon R3-100 Turret (3x12)    Range 30 000km     TS: 16000 km/s     Power 0-0     RM 3    ROF 5        1 1 1 0 0 0 0 0 0 0
Fire Control S04 64-16000 (1)    Max Range: 128 000 km   TS: 16000 km/s     92 84 77 69 61 53 45 37 30 22

This design is classed as a Military Vessel for maintenance purposes

vs

Code: [Select]

Flower-R class Destroyer Escort    9 000 tons     243 Crew     1432 BP      TCS 180  TH 1440  EM 0
8000 km/s     Armour 4-38     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 4     PPV 36
Maint Life 1.11 Years     MSP 398    AFR 162%    IFR 2.2%    1YR 327    5YR 4907    Max Repair 324 MSP
Intended Deployment Time: 10 months    Spare Berths 0   

720 EP Magneto-plasma Drive (2)    Power 720    Fuel Use 23.05%    Signature 720    Exp 9%
Fuel Capacity 250 000 Litres    Range 21.7 billion km   (31 days at full power)

10cm Railgun V4/C3 (12x4)    Range 40 000km     TS: 8000 km/s     Power 3-3     RM 4    ROF 5        1 1 1 1 0 0 0 0 0 0
Fire Control S02 64-8000 (1)    Max Range: 128 000 km   TS: 8000 km/s     92 84 77 69 61 53 45 37 30 22
Stellarator Fusion Reactor Technology PB-1 (6)     Total Power Output 36    Armour 0    Exp 5%

This design is classed as a Military Vessel for maintenance purposes

 At Magneto-Plasma drives I could still get 2/3 as many shots at twice the tracking speed out of R3 Gauss guns on a comparable ship (slightly larger, slightly cheaper, same engine)... i.e. 50% more effective firepower against reasonably fast missiles.
Comparing this on a RP budget instead of equal tech would help the railgun vessel, but wouldn't put it in the lead. However: Twice the speed (8k instead of just under 4k in my case) at no additional fuel use is normally hugely expensive, we are getting it at a bargain. How much does it matter? For a pure escort, it may only postpone obsolescence... or it may be central to your doctrine.

[Jorgen_CAB]

I think this is rather simple.

Given you fight against someone with your own level of technology you generally are not going to want to use Rail-guns for ships dedicated to PD service outside the early game tech levels.

You can make exceptionally fast gunships into decent PD ships as a secondary role, but outside that you want to use either lasers or Gauss as your main PD defenses.

If you go with a high speed beam fleet then it might be considered but it will still be very inefficient in comparison with a fleet that dedicate much less tonnage and cost to engines and by extension maintenance and upgrade costs on their ships.

[Iranon]

I'm not sure I agree.

Railgun ships on an equal tech basis won't do quite as well at point defense if speed is no issue in itself... but if you're comparing things on a RP budget and have more to spend on engines, every other military and civilian design gets better, as do the missiles.

Discounting armoured missiles or plasma torpedos (neither currently a concern?), lasers don't get benefits from their higher damage as PD. And as I argued, having them track fast is unlikely to overcome the RoF advantage of Railguns (Gauss, of course, have both). So while I can get behind arguments that Gauss weaponry does better... I can't for Lasers.

Regarding upgrades: Engine upgrades would be expensive for railgun ships consisting of 50% engines. Upgrades are generally inefficient, getting new engines for increased tracking speed isn't worth it. However: As opposed to slower escorts with turreted PD, you don't need to make engine upgrades just so the ships can keep up with your main fleet. You may wish to mothball obsolescent ships that aren't worth their running cost in everyday operations, but they'll do their thing without slowing anything down decades later.

[sneer]

it is always woth to upgrade fire controls or ewar but engines ? it will be close to 50% or more cost of new ship it is not justified

[amimai]

Most of my PD is provided by 10cm-15cm rapid fire laser cannons carried by the massive numbers of heavy fighters my fleets carry
(i have at least 1 fighter bay/10000tones on most ships)

capital ships (15000+ tones) may have 1-2 15cm-25cm quad laser turrets on them, but other then that my main line ships are pure missile carriers

at the end of the day nothing beats 100+ amm's flying out of your ship every 5 seconds

[sneer]

100 amm even fast ones can be beaten by 30-40 quad gauss turrets
with 1 per 5-8kt of fleet tonnage such PD can be mounted on 200kt fleet