Patrol space with more smaller ships using mainly sensors and some defensive weapons. This and DSTS to detect them in time to intercept them with scattered small fleets in strategic places.

You can easily patrol areas using cycled orders for ships and never really needing to bother with them other than change their patrol patterns.

The hardest part for defending civilian shipping is by far detection.

Due to the stealth tech raiders have you need to be able to detect a ship signature of around 1,000 tons or a thermal signature of around 200 (your numbers may vary due to their tech level) and as such your options are to use large active sensors covering around 140m km or a large passives covering around 50m km (with a little investment in sensor tech). Neither of these are very useful when covering say a 4b KM trade route out to a jump point, as you need lots of sensor platforms to cover this and they will all be military ships so will need maintenance.

Your best bet for detection is actually large amounts of deep space tracking stations as they cover a comparatively huge area, then when you detect raider ships station a sensor ship near the point you found them. With any luck you are able to narrow down where their current jump point is and just repeat this when it appears to have moved. This covers the inner system of most reasonable size systems without requiring maintenance micro.

For actually protecting civilian shipping I have been placing escort carriers with FACs along the busy trade routes and just have them sit there. My FACs are very fast at around 9kms with a range of around 3b km so I space the escort carriers around 1.5b km apart along the trade route. As soon as a raider is detected near the trade route or a civilian ship is attack I'll launch my FACs to go kill them. Having the escort carriers stationed along the route drastically cuts down on the time to react and means they only every destroy a couple of ships even on the busy routes.

I have been playing around with the idea of active sensor buoys but they die over the course of a few months it seems and with a size 99 missile I can get a detection range of around 30m km so would again need a stupid number of missile constantly and I'm not sure if I could automate the deployment of them. I also need to look into seeing if some sort of two stage mine with a very large sensor ont he first stage and a very small missile in the second would function longer as I have not heard of minefields disappearing after a while.

As a member of the Round Tonnage Lobby, I have to ask you to increase the mass of your ship until it is 20K tons.

Yeah, that was one of the things that I was wondering about. My thinking was that the turrets are only slightly larger (300 vs 359 for the 20cm) than the unturreted lasers for a 25% increase in tracking speed, so I thought it might be worth it, since my raiders currently have a speed of 4600 km/s. This way I am sure that the tracking speed exceeds the raiders and the turrets also get 2 layers of armor for protection, so there is less of a chance of being disarmed. Though it might be worth it to focus on the next research tech for base tracking speed and then try to squeeze in an additional laser instead of the turrets.

If we assume spherical cows, then I think that the difference in point-blank alpha strike damage is pretty small. I didn't bother calculating DPS since raiders are pretty fragile and can't handle slugging matches.

• A 300t laser doing 10 damage would have 87% accuracy, resulting in an expected 0.0290 damage/ton
• A 359t turret doing 10 damage would have 100% accuracy, resulting in an expected 0.0286 damage/ton

The turrets would cost more to research, but that comes out of the science, not the naval, budget.

That is a really interesting design. So the maintenance modules essentially counteract the ticking maintenance clock of the parasites in a civilian hangar?

Yep! It's better to think of the Toukon as a mobile maintenance base rather than a traditional carrier. This means that I can ignore my escort carriers during day-to-day life; I only have to pay attention to them if they run into trouble.

The biggest enemy in my games is typically not raiders or NPRs, but rather the limitations of my short/medium-term memory. While others may keep notes or spreadsheets to mitigate this problem, I prefer to roleplay this as imperial overreach: as the empire gets bigger and bigger, Terra's bureaucracy becomes less and less efficient.

Beam parasites would arguably require even less micromanagement, but in practice I get more enjoyment from seeing "4x Nuclear Detonation: Strength 20" than "10x Energy Weapon Impact: Strength 1" when avenging my murdered civilians.

One is specific feedback on an escort ship, that I expect to start sending out together with every long distance cargo/colonist fleet. I would be very interested in seeing other designs for similar purposes and get a feeling of whether this would do the job. The idea is that they will primarily serve to scare off the lone raiders, so they don't get a free pass on unprotected fleets, and also be able to draw fire and defend themselves against smaller raider fleets. I don't expect that defence against a full raider fleet is a realistic goal for these kinds of escorts (though I may be setting the bar too low here). In that scenario they just need to do enough damage to either scare off the remaining raiders or buy time for the main patrol fleet. I also don't expect that they will need to chase down fleeing raiders, so speed is not a primary concern, but fuel efficiency is, since they need to travel many many kilometers.

I think that your escort ship should fare well in a fight. Why are the smaller lasers turreted though? Their tracking speeds appear to be only marginally higher than your racial tracking speed (5kkm/s vs 4kkm/s).

My approach has been also been to use escort carriers. My implementation is a commercial carrier with maintenance modules and 12 missile fighters. The carriers can be deployed for ~17 years at a time, so they're also great for camping in empty systems or near suspected Raider jump points.
Toukon class Auxiliary Carrier      63,834 tons       515 Crew       2,993.9 BP       TCS 1,277    TH 2,400    EM 0
1879 km/s      Armour 5-142       Shields 0-0       HTK 105      Sensors 11/11/0/0      DCR 11      PPV 0
MSP 7,529    Max Repair 100 MSP
Hangar Deck Capacity 6,000 tons     Magazine 1,500    Cargo Shuttle Multiplier 2   
Commander    Control Rating 3   BRG   AUX   PFC   
Intended Deployment Time: 3 months    Flight Crew Berths 120   
Maintenance Modules: 3 module(s) capable of supporting ships of 7,500 tons

Tamrat Turbines Commercial Magnetic Fusion Drive  EP600.00 (4)    Power 2400    Fuel Use 0.78%    Signature 600    Explosion 3%
Fuel Capacity 5,000,000 Litres    Range 1,808.1 billion km (11137 days at full power)

Lee Kinetics CIWS-250 (5x8)    Range 1000 km     TS: 25,000 km/s     ROF 5       
Abbas Ordnance SRM (187)    Speed: 40,000 km/s    End: 6.6m     Range: 15.9m km    WH: 20    Size: 8    TH: 200/120/60

Fox Electronics EM Sensor EM1.0-11.0 (1)     Sensitivity 11     Detect Sig Strength 1000:  26.2m km
Fox Electronics Thermal Sensor TH1.0-11.0 (1)     Sensitivity 11     Detect Sig Strength 1000:  26.2m km

Strike Group
12x Assassin Torpedo Bomber   Speed: 12010 km/s    Size: 9.99

Missile to hit chances are vs targets moving at 3000 km/s, 5000 km/s and 10,000 km/s

This design is classed as a Commercial Vessel for maintenance purposes
This design is classed as a Carrier for auto-assignment purposesAssassin class Torpedo Bomber      500 tons       3 Crew       107.6 BP       TCS 10    TH 120    EM 0
12010 km/s      Armour 1-5       Shields 0-0       HTK 6      Sensors 0/0/0/0      DCR 0      PPV 4.8
Maint Life 7.37 Years     MSP 93    AFR 20%    IFR 0.3%    1YR 3    5YR 45    Max Repair 60 MSP
Magazine 32   
Lieutenant Commander    Control Rating 1   
Intended Deployment Time: 6 days    Morale Check Required   

Tamrat Turbines Magnetic Fusion Drive  EP120.00 (1)    Power 120    Fuel Use 619.68%    Signature 120    Explosion 20%
Fuel Capacity 50,000 Litres    Range 2.91 billion km (67 hours at full power)

Size 8 Box Launcher (4)     Missile Size: 8    Hangar Reload 141 minutes    MF Reload 23 hours
Lu Sensor Systems Missile Fire Control FC15-R5 (1)     Range 15.5m km    Resolution 5
Abbas Ordnance SRM (4)    Speed: 40,000 km/s    End: 6.6m     Range: 15.9m km    WH: 20    Size: 8    TH: 200/120/60

Lu Sensor Systems Active Search Sensor AS15-R5 (1)     GPS 72     Range 15.5m km    Resolution 5

Missile to hit chances are vs targets moving at 3000 km/s, 5000 km/s and 10,000 km/s

This design is classed as a Fighter for production, combat and planetary interaction
This design is classed as a Fighter for auto-assignment purposes
So far I've only lost one carrier: I deployed all of its fighters to chase a Raider squadron, but then it got ambushed by a full Raider fleet. The carrier was lost after its magazines exploded, but the fighters managed to make it to a nearby colony and wait for reinforcements.

If I ever feel like implementing military budget cuts, I also think that I could probably get away with 4 fighters per escort carrier instead of 12.

The second question concerns more general strategies. A ship like this can do nothing against civilian shipping lanes. It would be way too much micromanagement to actually follow the civilian fleets around, but because combat is so fast, it is almost impossible to get there in time, even if a ship is nearby already. This is especially a problem in empty systems, where there aren't even any colonies with the standard set of patrol crafts ready for dispatch.

What have you so far found to be useful working strategies? Do you use strategically placed deep space populations with maintained patrol fleets for quick dispatch in all systems? Do you have patrol fleets that fly constantly along shipping lanes to important colonies? Is it possible to fortify a system to such an extent that raiders are less likely to spawn there? Do you have a developed system of deployed to discover them before they reach the shipping lanes and catch them with a fast fleet?

I usually don't actively protect my civilian fleets - as you mentioned, they tend to be too spread out for reaction forces to respond effectively. Their wrecks do however make great bait for ambushing Raider salvagers.

The introduction of the new raiders has given me a few dilemmas that I have not had to consider before, mostly due to me abusing my knowledge of the AI to only provide protection where I knew it was needed. This meant often sending infrastructure, installations, and colonists to far away colonies without protection, simply because I knew it was in a line of systems where aliens most likely would not bother me.

Now things are entirely different. First change was of course to begin colonisation by sending ground units with STO's to make sure that the raiders simply would not destroy or invade the newly established colony and for more established colonies to send maintenance facilities and a patrol fleet to ensure that a larger fleet of raiders would not go on a rampage unobstructed.

However, most recently I ran into a different problem. A fleet of tugs and ark modules was attacked and destroyed in one of the two empty systems that are between my main planet and the new colony. Fortunately I had a fleet heading back in the same system at that time and managed to deal with the raiders easy enough, but since some of these tugging fleets move extremely slowly, there is a very high chance that a new raider fleet will spawn in a system where a fleet of tugs already is and then they are absolutely helpless. And even if I have a patrol fleet either passing through or stationed at a deep space population, it is unlikely that they will arrive in time to prevent the destruction of colonists or cargo - even if they might depose of the raiders afterwards and thus prevent further damage.

So, I have two questions. One is specific feedback on an escort ship, that I expect to start sending out together with every long distance cargo/colonist fleet. I would be very interested in seeing other designs for similar purposes and get a feeling of whether this would do the job. The idea is that they will primarily serve to scare off the lone raiders, so they don't get a free pass on unprotected fleets, and also be able to draw fire and defend themselves against smaller raider fleets. I don't expect that defence against a full raider fleet is a realistic goal for these kinds of escorts (though I may be setting the bar too low here). In that scenario they just need to do enough damage to either scare off the remaining raiders or buy time for the main patrol fleet. I also don't expect that they will need to chase down fleeing raiders, so speed is not a primary concern, but fuel efficiency is, since they need to travel many many kilometers.

I am aiming for 20k ton total, so there is a bit of room left.

Pegasus class Civilian Escort (P)      19,332 tons       419 Crew       3,054 BP       TCS 387    TH 750    EM 10,200
1939 km/s      Armour 8-64       Shields 340-425       HTK 125      Sensors 22/0/0/0      DCR 18      PPV 57.7
Maint Life 5.32 Years     MSP 5,789    AFR 374%    IFR 5.2%    1YR 343    5YR 5,138    Max Repair 153.0 MSP
Captain    Control Rating 3   BRG   AUX   ENG   
Intended Deployment Time: 60 months    Morale Check Required   

Commercial Ion Drive  EP375.00 (2)    Power 750    Fuel Use 4.33%    Signature 375    Explosion 5%
Fuel Capacity 350,000 Litres    Range 75.2 billion km (449 days at full power)
Epsilon S85 / R425 Shields (4)     Recharge Time 425 seconds (0.8 per second)

31.250cm C5 Soft X-ray Laser (1)    Range 256,000km     TS: 4,000 km/s     Power 26-5     RM 60,000 km    ROF 30       
Single 25.0cm C5 Soft X-ray Laser Turret (2x1)    Range 256,000km     TS: 5000 km/s     Power 16-5     RM 60,000 km    ROF 20       
Single 20cm C5 Soft X-ray Laser Turret (4x1)    Range 256,000km     TS: 5000 km/s     Power 10-5     RM 60,000 km    ROF 10       
Beam Fire Control R256-TS5000 (2)     Max Range: 256,000 km   TS: 5,000 km/s     96 92 88 84 80 77 73 69 65 61
Magnetic Mirror Fusion Reactor R18 (3)     Total Power Output 54    Exp 5%

Active Search Sensor AS12-R20 (1)     GPS 112     Range 12m km    Resolution 20
Thermal Sensor TH2-22 (1)     Sensitivity 22     Detect Sig Strength 1000:  37.1m km

ECCM-1 (1)         ECM 10

This design is classed as a Military Vessel for maintenance purposes
This design is classed as a Warship for auto-assignment purposes

The second question concerns more general strategies. A ship like this can do nothing against civilian shipping lanes. It would be way too much micromanagement to actually follow the civilian fleets around, but because combat is so fast, it is almost impossible to get there in time, even if a ship is nearby already. This is especially a problem in empty systems, where there aren't even any colonies with the standard set of patrol crafts ready for dispatch.

What have you so far found to be useful working strategies? Do you use strategically placed deep space populations with maintained patrol fleets for quick dispatch in all systems? Do you have patrol fleets that fly constantly along shipping lanes to important colonies? Is it possible to fortify a system to such an extent that raiders are less likely to spawn there? Do you have a developed system of deployed to discover them before they reach the shipping lanes and catch them with a fast fleet?