I'm faced with a situation where almost every tech has advanced since the last round of refits, so the cost to refit is almost the same as building new. I wondered what other people do in this situation.
Here is the existing Sword class frigate:
Sword II class Frigate 9,375 tons 284 Crew 1,571 BP TCS 187 TH 900 EM 1,380
4800 km/s Armour 4-39 Shields 46-368 HTK 64 Sensors 6/8/0/0 DCR 6 PPV 44.32
Maint Life 2.65 Years MSP 628 AFR 117% IFR 1.6% 1YR 127 5YR 1,902 Max Repair 225 MSP
Commander Control Rating 2 BRG AUX
Intended Deployment Time: 12 months Morale Check Required
Ravenor Drive Systems RDS-450B Ion Drive (2) Power 900 Fuel Use 63.75% Signature 450 Explosion 12%
Fuel Capacity 656,000 Litres Range 19.8 billion km (47 days at full power)
Valentinian-Stern VS-46 Void Shield (1) Recharge Time 368 seconds (0.1 per second)
Astaroth Kinetics AK-20 Weapons Battery (4x4) Range 160,000km TS: 4,800 km/s Power 12-4 RM 40,000 km ROF 15
Dominus-Varnus Defence Systems DV-2 Defence Turret (1x6) Range 30,000km TS: 16000 km/s Power 0-0 RM 30,000 km ROF 5
MK I Defence Turret Fire Control (1) Max Range: 64,000 km TS: 16,000 km/s 84 69 53 38 22 6 0 0 0 0
MK II Energy Weapon Fire Control (2) Max Range: 256,000 km TS: 4,800 km/s 96 92 88 84 80 77 73 69 65 61
R-8 Magnetic Mirror Fusion Reactor (2) Total Power Output 16.6 Exp 5%
MK II Frigate Active Augur Array (1) GPS 8640 Range 66.8m km Resolution 120
MK II Torpedo Detection Array (1) GPS 32 Range 9m km MCR 812.4k km Resolution 1
MK I Thermal Augur Array (1) Sensitivity 6 Detect Sig Strength 1000: 19.4m km
MK II Electromagnetic Augur Array (1) Sensitivity 8 Detect Sig Strength 1000: 22.4m km
Here is the latest design. Apart from the obvious new engines, I have to add fire controls that match the higher speed. Better weapons are available and I also have ECM/ECCM, improved sensors and improved shields.
Sword III class Frigate 9,600 tons 310 Crew 1,814.3 BP TCS 192 TH 1,152 EM 2,130
6000 km/s Armour 4-40 Shields 71-426 HTK 70 Sensors 8/11/0/0 DCR 6 PPV 40
Maint Life 2.44 Years MSP 708 AFR 123% IFR 1.7% 1YR 163 5YR 2,452 Max Repair 288 MSP
Commander Control Rating 2 BRG AUX
Intended Deployment Time: 12 months Morale Check Required
Ravenor RDS-576-B Magneto-Plasma Drive (2) Power 1152 Fuel Use 63.75% Signature 576 Explosion 12%
Fuel Capacity 642,000 Litres Range 18.9 billion km (36 days at full power)
Valentinian-Stern VS-70 Void Shield (1) Recharge Time 426 seconds (0.2 per second)
Astaroth Kinetics AK-25 Weapons Battery (5x4) Range 250,000km TS: 6,000 km/s Power 15-3.75 RM 50,000 km ROF 20
MK III Energy Weapon Fire Control (2) Max Range: 256,000 km TS: 6,000 km/s 96 92 88 84 80 77 73 69 65 61
R-9 Stellarator Fusion Reactor (2) Total Power Output 19 Exp 5%
MK III Frigate Active Augur Array (1) GPS 8190 Range 76.2m km Resolution 120
MK III Torpedo Detection Array (1) GPS 21 Range 8.6m km MCR 771.7k km Resolution 1
MK II Thermal Augur Array (1) Sensitivity 8 Detect Sig Strength 1000: 22.4m km
MK III Electromagnetic Augur Array (1) Sensitivity 11 Detect Sig Strength 1000: 26.2m km
ECCM-1 (1) ECM 10
Refit cost is 1733 BP (compared to 1814 BP) for new build, although it includes only 1416 tons of minerals. The obvious con is that I could build a new ship for virtually the same amount. The pros are that I preserve the experienced crew and I don't end up with out of date ships that I have to maintain anyway. With the total tonnage requirement for maintenance in C# Aurora, overall maintenance capacity is a consideration in addition to the required MSP to keep the ship maintained. Regarding the latter point, I suppose the 'cost' of a ship should include the maintenance. The MSP requirement over ten years would be 3x class cost, which is 75% of ship cost in wealth and minerals. When that is considered, the refit cost is a smaller percentage of the whole.
An alternative is a refit that leave some systems, such as weapons, intact and only upgrades engines, shields and electronics. This would cost 1154 BP, of which 942 tons would minerals. The pro is that it is cheaper and therefore I can refit more ships for the same time and cost plus the ship can operate with new Sword IIIs, but it leaves the design much shorter-ranged weapons and no ECM/ECCM..
Sword II - B class Frigate 9,600 tons 290 Crew 1,789.7 BP TCS 192 TH 1,152 EM 2,130
6000 km/s Armour 4-40 Shields 71-426 HTK 64 Sensors 8/11/0/0 DCR 6 PPV 44.32
Maint Life 2.42 Years MSP 699 AFR 123% IFR 1.7% 1YR 164 5YR 2,456 Max Repair 288 MSP
Commander Control Rating 2 BRG AUX
Intended Deployment Time: 12 months Morale Check Required
Ravenor RDS-576-B Magneto-Plasma Drive (2) Power 1152 Fuel Use 63.75% Signature 576 Explosion 12%
Fuel Capacity 611,000 Litres Range 18 billion km (34 days at full power)
Valentinian-Stern VS-70 Void Shield (1) Recharge Time 426 seconds (0.2 per second)
Astaroth Kinetics AK-20 Weapons Battery (4x4) Range 160,000km TS: 6,000 km/s Power 12-4 RM 40,000 km ROF 15
Dominus-Varnus Defence Systems DV-2 Defence Turret (1x6) Range 30,000km TS: 16000 km/s Power 0-0 RM 30,000 km ROF 5
MK I Defence Turret Fire Control (1) Max Range: 64,000 km TS: 16,000 km/s 84 69 53 38 22 6 0 0 0 0
MK III Energy Weapon Fire Control (2) Max Range: 256,000 km TS: 6,000 km/s 96 92 88 84 80 77 73 69 65 61
R-8 Magnetic Mirror Fusion Reactor (2) Total Power Output 16.6 Exp 5%
MK III Frigate Active Augur Array (1) GPS 8190 Range 76.2m km Resolution 120
MK II Torpedo Detection Array (1) GPS 32 Range 9m km MCR 812.4k km Resolution 1
MK II Thermal Augur Array (1) Sensitivity 8 Detect Sig Strength 1000: 22.4m km
MK III Electromagnetic Augur Array (1) Sensitivity 11 Detect Sig Strength 1000: 26.2m km
Or I just keep the old ships un-refitted and hope I run into a threat against which they would be useful. Currently I am refitting to the II-B design and building a small number of IIIs from scratch, but not I'm not convinced I have the best strategy so interested in opinions.