better engine efficiency vs size

[letsdance (OP)]

i don't quite understand why so many people focus so much on mission tonnage per ship. if you are size restricted (eg spaceyard size) you can reduce mission tonnage and build more ships instead. ships will be cheaper and therefore build faster. you get the same mission tonnage over the same period of time. the points of time when ships are finished will be different of course, but that's actually another advantage of using less tonnage per ship because you have the first ships sooner.

[alex_brunius]

i don't quite understand why so many people focus so much on mission tonnage per ship. if you are size restricted (eg spaceyard size) you can reduce mission tonnage and build more ships instead.

Now you can't. Building more ships means they wont be finished until many years later when they are obsolete and already worthless.

If I normally build 3x3 Cruisers with 60% mission tonnage and you suggest to replace it with a design that has 20% mission tonnage I need to build 3x9 Cruisers and that would add say 6-9 years before all of them are ready for service.

And it's equally hard to add slipways that it is to expand size on shipyards, so the restriction is on shipyard space is the total amount including all slipways.

you get the same mission tonnage over the same period of time

That's not true, please show me an example of a ship with 20% mission tonnage and same total tonnage is 3 times faster to build then a design with 60% mission tonnage!



To illustrate the point I tested two very basic designs:

1.) 60% launchers, 25% engines (8 of them) of max power mod (6300ton and 6100km/s).   2.21 years buildtime and 1001 BPs. ( 0.88 years maintlife )
2.) 20% launchers, 63.5% engines (5 of them) of low power mod (6300ton and 6100km/s).  1.42 years buildtime and 640 BPs. ( 0.42 years maintlife )


Building a series of 3 ships of design 1 will take my empire 6.63 years and cost me 3003 wealth and minerals.
Building a series of 9 ships of design 2 will take my empire 12.78 years and cost me 5760 wealth and minerals.

So almost double build-time and total cost to get the same mission tonnage using your "optimal" strategy in practice.

Notice also that this is "best case" scenario with minimal amount of generic components shared between the ships except what the default ship start with (1x bridge/fuel/eng). If we add more generic components shared between the ships like sensors, FC, armor and so on their difference in buildtime per ship will become even smaller.

[Whitecold]

i don't quite understand why so many people focus so much on mission tonnage per ship. if you are size restricted (eg spaceyard size) you can reduce mission tonnage and build more ships instead. ships will be cheaper and therefore build faster. you get the same mission tonnage over the same period of time. the points of time when ships are finished will be different of course, but that's actually another advantage of using less tonnage per ship because you have the first ships sooner.

If you change a 20k warship with 15k mission tonnage and 5k engine (25%) to 50% you get a 30k ship, you additionally need 1.5 engineering spaces, as maintenance spaces work proportional to total tonnage, you need approx. 30% more armor to cover the engines, this additional armor is costly and provides far less protection than if it would be invested in thicker armor.
If you would build 3 20k ships instead of two, you would need 50% more armor and engineering. Armor is only worth what it is protecting. The same goes for shielding on multiple ships, split on 3 ships instead of 2 you only get 2/3 of the protection.

[Jorgen_CAB]

Another thing to note is that if you make the engines bigger with the same power setting you actually will need more engineering mass in proportion than before to get the same maintenance window on your ship, this also translate to more crew and more crew compartments. So if you make the engine 50% bigger and want the same mission package and speed the ship will be more than 50% bigger and thereby actually slower if you don't compensate with yet bigger engines.

This is also why I make my bigger ships slower than my smaller ships, their economy is that they get a bigger mission package and less engines that also has less power per mass. The effect is a dynamic fleet with different speeds but bigger ships and very fuel efficient and can easier upgrade their engines with new technology and have a heavier mission package than smaller more specialized ships.

This is more a general rule in my fleet and it will work of you build your doctrines around ships with different speeds.

[Jorgen_CAB]

i don't quite understand why so many people focus so much on mission tonnage per ship. if you are size restricted (eg spaceyard size) you can reduce mission tonnage and build more ships instead. ships will be cheaper and therefore build faster. you get the same mission tonnage over the same period of time. the points of time when ships are finished will be different of course, but that's actually another advantage of using less tonnage per ship because you have the first ships sooner.

I think it would be better if you presented two designs where this tactic is applied and we can discuss it from there. Becasue I'm not sure I fully understand exactly how you envision this to be superior, and as I said before I don't think it will be a the one that fit all solutions.

[letsdance (OP)]

Now you can't. Building more ships means they wont be finished until many years later when they are obsolete and already worthless.

not if they are faster to build, which was my point.

2.) 20% launchers, 63.5% engines

63 % is too much. it should be 50 % max (maybe 40 or 45 % would be better in your case). which would give you 33 % (or more) launchers - that's a big difference! try it and post the complete designs (like i did below) with all values, not just speeds.

I think it would be better if you presented two designs where this tactic is applied and we can discuss it from there. Becasue I'm not sure I fully understand exactly how you envision this to be superior, and as I said before I don't think it will be a the one that fit all solutions.

good idea! and yes, it doesn't fit all solutions. but the point is, the cheaper engines with less fuel usage and research cost should never (or rarely) be equal or in every regard better to something more expensive.

since people complained when i used higher tech examples and slow engines, i created 2 engines for testing. these are HS 50, their research cost was 2,250 (A)and 6,000 (B). the result is quite interesting...

missile1 class Cruiser    10,000 tons     208 Crew     1358 BP      TCS 200  TH 1200  EM 0
6000 km/s     Armour 3-41     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 7     PPV 24
Maint Life 2.01 Years     MSP 594    AFR 114%    IFR 1.6%    1YR 196    5YR 2936    Max Repair 225 MSP
Intended Deployment Time: 12 months    Spare Berths 1    
Magazine 549    

600 EP Magneto-plasma Drive - x 0.75 - FE 0.12 (2)    Power 600    Fuel Use 12.18%    Signature 600    Exp 7%
Fuel Capacity 500,000 Litres    Range 73.9 billion km   (142 days at full power)

Size 6 Missile Launcher RoF 30s (4)    Missile Size 6    Rate of Fire 30
Missile Fire Control FC552-R16 (1)     Range 553.0m km    Resolution 16

missile2 class Cruiser    10,000 tons     209 Crew     1658 BP      TCS 200  TH 1200  EM 0
6000 km/s     Armour 3-41     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 7     PPV 24
Maint Life 1.95 Years     MSP 725    AFR 114%    IFR 1.6%    1YR 250    5YR 3749    Max Repair 600 MSP
Intended Deployment Time: 12 months    Spare Berths 0    
Magazine 549    

1200 EP Magneto-plasma Drive - x1.5 - FE 0.69 (1)    Power 1200    Fuel Use 68.89%    Signature 1200    Exp 15%
Fuel Capacity 3,000,000 Litres    Range 78.4 billion km   (151 days at full power)

Size 6 Missile Launcher RoF 30s (4)    Missile Size 6    Rate of Fire 30
Missile Fire Control FC552-R16 (1)     Range 553.0m km    Resolution 16

war tonnage is actually the same on both designs, because all the advantage of B's smaller engine is eaten up by the larger fuel tank required to achieve the same range. you pay 22 % more for nothing. obviously, if we reduce range it gets better.

we've just seen that better fuel usage techs are in favor to the more powerful engines. this suggests that it becomes even worse in later tech levels.

so lets use a design from my current game instead, shall we? missile A is a design that i'm using right now. both drives used are internal confinement fusion drives and have HS 50.

missile A class Cruiser    10,000 tons     199 Crew     1083.4 BP      TCS 200  TH 960  EM 0
4800 km/s     Armour 2-41     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 10     PPV 30
Maint Life 4.07 Years     MSP 677    AFR 80%    IFR 1.1%    1YR 66    5YR 983    Max Repair 192 MSP
Intended Deployment Time: 24 months    Spare Berths 0    
Magazine 630    

Comm Drive 0480 EP - FE 0.006 (2)    Power 480    Fuel Use 0.62%    Signature 480    Exp 3%
Fuel Capacity 50,000 Litres    Range 145.2 billion km   (350 days at full power)

Size 6 Missile Launcher RoF 30s (5)    Missile Size 6    Rate of Fire 30
Missile Fire Control FC552-R16 (1)     Range 553.0m km    Resolution 16

missile B class Cruiser    10,000 tons     271 Crew     1743.4 BP      TCS 200  TH 960  EM 0
4800 km/s     Armour 2-41     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 10     PPV 48
Maint Life 3.73 Years     MSP 1090    AFR 80%    IFR 1.1%    1YR 122    5YR 1833    Max Repair 288 MSP
Intended Deployment Time: 24 months    Spare Berths 1    
Magazine 1023    

Mil Drive 0960 EP - FE 0.035 (1)    Power 960    Fuel Use 3.49%    Signature 960    Exp 6%
Fuel Capacity 250,000 Litres    Range 128.9 billion km   (310 days at full power)

Size 6 Missile Launcher RoF 30s (8)    Missile Size 6    Rate of Fire 30
Missile Fire Control FC552-R16 (2)     Range 553.0m km    Resolution 16

missile B has 60% more missile launchers. it has 100% more fire controls and 60% more missile storage. the rest is about the same. well, except that it needs almost 6 times as much fuel. design B build costs are 64 % higher than design A.

all in all, design B is just 60 % "more". 60 % more weapons, 62 % more missiles and 61 % higher costs which also means 60 % longer build time. ship range is 10 % less. it has one advantage, which is one fire control per 4 launchers instead of one per 5 launchers (i couldn't give it 1.6 fire controls...). but it needs about 3 times as much fuel to move one launcher around, the engine was more expensive to research and you have no backup if you lose one engine. it also has a shorter maint life, but that's probably due to the better fc coverage so lets ignore this.

instead of building 10 missile B you could as well build 16 missile A. if you increase armor to 5, design B build cost are only 54 % higher. so you would have a 5 % cost advantage here. but i usually don't put armor on missile ships. if armor is reduced to 1, design B is in compare even more expensive by 2 %. if you use shields it doesn't matter. if you want a faster ship, both engines are higher power, but missile B loses more war tonnage to increased fuel tank requirements.

also note that 10k is the optimum tonnage in favor of the stronger engine. if the ship is smaller, you build one larger engine with lower power and get additional fuel savings from engine size.

at last i'll repeat it:
the cheaper engines with less fuel usage and research cost should never (or at least rarely) be equal or in every regard better to something more expensive.

[Jorgen_CAB]

Ok, I see what you are getting at and this is also why I often use lower power settings on my bigger ships, it makes the engines much cheaper, less costly to research and cost less supplies thus less maintenance facilities, space for fuel and all that stuff.

I must say though that the designs are sort of strange, the range on the are not realistic and some of them can't take a hit in the engine without having to be dragged back to a shipyard by a tug. I really don't think such designs are realistic to use on a main combat ship, on a small FAC or corvette with very small deployment time, yes.

It is a waste of resources to add power settings to ships you wish to use as normal ships for the same reasons, higher multiplier should only be used for short ranged craft with very limited ranges such as FAC and fighters who can benefit from it much more.

Here are two more reasonable example why I think you must sacrifice something to gain something else...

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Iowa (A) class Cruiser    10,000 tons     267 Crew     1454 BP      TCS 200  TH 720  EM 0
3600 km/s     Armour 5-41     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 5     PPV 53.46
Maint Life 2.52 Years     MSP 500    AFR 145%    IFR 2%    1YR 110    5YR 1646    Max Repair 120 MSP
Intended Deployment Time: 9 months    Flight Crew Berths 26    
Hangar Deck Capacity 1000 tons     Magazine 150    

240 EP (HS20) Ion Drive (3)    Power 240    Fuel Use 48%    Signature 240    Exp 10%
Fuel Capacity 400,000 Litres    Range 15.0 billion km   (48 days at full power)

Twin 15cm C3 Ultraviolet Laser Turret (6x2)    Range 0km     TS: 6000 km/s     Power 12-6     RM 4    ROF 10        0 0 0 0 0 0 0 0 0 0
Gas-Cooled Fast Reactor Technology PB-1 (8)     Total Power Output 36    Armour 0    Exp 5%
This design is classed as a Military Vessel for maintenance purposes


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Iowa (B) class Cruiser    10,750 tons     258 Crew     1348.75 BP      TCS 215  TH 702  EM 0
3265 km/s     Armour 5-43     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 4     PPV 53.46
Maint Life 2.53 Years     MSP 372    AFR 194%    IFR 2.7%    1YR 81    5YR 1212    Max Repair 63 MSP
Intended Deployment Time: 9 months    Flight Crew Berths 35    
Hangar Deck Capacity 1000 tons     Magazine 150    

117 EP (HS13) Ion Drive (6)    Power 117    Fuel Use 25.43%    Signature 117    Exp 7%
Fuel Capacity 230,000 Litres    Range 15.1 billion km   (53 days at full power)

Twin 15cm C3 Ultraviolet Laser Turret (6x2)    Range 0km     TS: 6000 km/s     Power 12-6     RM 4    ROF 10        0 0 0 0 0 0 0 0 0 0
Gas-Cooled Fast Reactor Technology PB-1 (8)     Total Power Output 36    Armour 0    Exp 5%
This design is classed as a Military Vessel for maintenance purposesIgnore the fact there are no sensors of FC on these ships, that is inconsequential...  

Here you can clearly see that you need to sacrifice speed to gain some advantage in fuel economy and a slightly cheaper ship. One good point though is that cruiser B is safer in combat and is much easier (cheaper) to refit the engines on later.

So in essence you will need to sacrifice something to gain something else. I don't think your examples was very good since they had way too much fuel built into the ship, there are no way you need all that fuel in a ship, that is why you use tankers.

If you turn up the power on the engines enough you will get a better and more distorted result since they require so much more fuel. So if you crank up the power of the engines you will end up sacrificing range and will need to rely more on tanker or the ship being stationed closer to any potential threat. Higher powered engine are probably only economically defensible if you have huge reserves of fuel, but that industry will cost as well so I don't think it is economically viable in the end, not in a multi national AI less campaign any way.


I have recognized these issues before and it is also why I gladly sacrifice some speed in my monster ships for less fuel usage and cheaper engines so I can refit and upgrade them in a more reasonable pace.

[Jorgen_CAB]

Here is the same ship using a x1.25 power ration on the engines...

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Iowa (C) class Cruiser    9,700 tons     264 Crew     1475 BP      TCS 194  TH 720  EM 0
3711 km/s     Armour 5-40     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 5     PPV 53.46
Maint Life 2.49 Years     MSP 475    AFR 150%    IFR 2.1%    1YR 106    5YR 1589    Max Repair 120 MSP
Intended Deployment Time: 9 months    Flight Crew Berths 29   
Hangar Deck Capacity 1000 tons     Magazine 150   

240 EP (HS16) Ion Drive (3)    Power 240    Fuel Use 88.04%    Signature 240    Exp 12%
Fuel Capacity 750,000 Litres    Range 15.8 billion km   (49 days at full power)

Twin 15cm C3 Ultraviolet Laser Turret (6x2)    Range 0km     TS: 6000 km/s     Power 12-6     RM 4    ROF 10        0 0 0 0 0 0 0 0 0 0
Gas-Cooled Fast Reactor Technology PB-1 (8)     Total Power Output 36    Armour 0    Exp 5%
This design is classed as a Military Vessel for maintenance purposes
It clearly shows it is viable to build that type of ship at those ranges if you can manage the extra drain in fuel.

[alex_brunius]

since people complained when i used higher tech examples and slow engines, i created 2 engines for testing. these are HS 50, their research cost was 2,250 (A)and 6,000 (B). the result is quite interesting...

Uhm seriously? The only thing this examples shows is that your ship design will be smegty of you devote 30% of the total tonnage to fuel ( more then engine even ). Not really groundbreaking news for anyone still in the thread I think...

Cut it to 5% instead ( 25 days ) and it will start to look more like a real warship with a speed advantage at 8000km/s. To catch it your other design will need to get rid of 2500 ton ( 4 size 6 launchers are 1200 ton and magazines about 1800 ton so over 2/3:eds of it's offensive capacity needs to go to make it work )...

so lets use a design from my current game instead, shall we?

Are you seriously using military designs with Fuel Use 0.62% and 4800km/s max speeds at internal confinement fusion engine levels?  

If all you need them to do is carry a bunch of missiles to within range any engine will work of-course, but why not use colliers and tankers to haul missiles and fuel across your empire instead like any normal military would?
The actual launch platform only needs range to make the last system and back to safety.


If you want to use your 4800km/s ship against any real opponent you would be in serious troubles since their ships could outrun yours with ease even if using 1-2 engine techs below you, so once your out of munitions it's game over.
And since your slow ships would have no chance to evade any attacks made even by such primitive opponents, well...

My current designs are 5000km/s with Ion engines!

[Jorgen_CAB]

To be fair... using any sort of ship with techs higher than Ion engines and missile weapons as the main weapon are probably not viable since most of your strike force should have transitioned to fighters by now so you can attack from such great distance the enemy don't even know where your main force is.

At a certain point pure missile ships become a liability for most fleet operations until you discover advance cloaking systems and ships again become a great source of missile warfare.

If you have to fire a missile inside the enemy active scanning envelope you are intentionally putting yourself in a precarious situation, that is why ships in my campaigns mostly have divergent speeds, because different ships have different needs.

Most military engagement are mostly about finding the enemy main force. The one who attack first usually have a serious advantage, that is why invading another factions space is so hard with ground based tracking stations being very powerful to detect enemy presence. Also, most big capital ships in my campaigns sacrifice speed for some additional long range beam weapons, so you don't just walk up to them and talk about it.  

I also like to mix it up, some factions rely more on speed and evasion manoeuvres than others, it sort of make it more interesting from a RP perspective.

[letsdance (OP)]

Here you can clearly see that you need to sacrifice speed to gain some advantage in fuel economy and a slightly cheaper ship.

i don't actually. if you have so small engines on your faster design, you should increase engine size instead of number, like this:

117 EP (HS13) Ion Drive (6)    Power 117    Fuel Use 25.43%    Signature 117    Exp 7%

use 3 of these instead:

265.2 EP (HS 26) Ion Drive (3)   Power 265.2   Fuel Use 29.6 %    Signature 265.2 Exp 7%

Iowa (B) will be about same build cost and speed at lower fuel cost.

The only thing this examples shows is that your ship design will be smegty

i would like to discuss it based on your design. but since you refuse to do so, i assume you already had a look at it and saw that i'm right

[Jorgen_CAB]

It is not feasible to build one specific engine for each and every ship you have. In my campaigns there usually are only a couple of engines. Smaller engines have allot of strategic value outside of being more fuel hungry such as lower maintenance cost, that is they require less engineering spaces per mass than a larger engine and can fit onto more ship hulls. I hope you also realize you don't have an infinite number of research points  and at some point you have to ask yourself if researching a new engine technology are more important than developing new engine types. I also understand that it highly depend in what environment that you play. If you don't have any real competition for dominance you don't have to care and can spend RP at hearts content. But when you are hard pressed for dominance and sending that colonizer just a few days earlier means everything you can't be so picky about engine size on your ships. Sometimes it is better with a destroyer now than a destroyer when the war is already over...

The Iowa A and C was just example ships, whether you decide to make the engines bigger and fewer are just a decision on whether you can afford the research and are willing to pay extra for more maintenance facilities on your ships for some extra lower fuel cost. The ships will actually be somewhat more expensive, just with a tiny bit though.

I would never have a ship with only one engine, more engines adds some safety and lower maintenance costs. I feel comfortable with two or three engines though. Most ships will have between two and five engines, it all depends on the availability of engine types and research facilities available to do the research for them.

[letsdance (OP)]

yes, but you could just research the less powerful engine instead of the more powerful one. that saves you research points. i don't know how many different sized ship designs you're using before getting any engine tech advances. i usually don't have many.

[Jorgen_CAB]

I do research less powerful engines on larger ships and more powerful engines on smaller ships, that is a general theme for the most part. And I do try to fit as few engines on ships as I possible can, but never less than two unless it is a FAC or Fighter. Using six engines in my example was perhaps not the best way to get my own principles across though and I would probably have used three larger engines on such a ship.

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Iowa (B2) class Cruiser    10,750 tons     264 Crew     1335.75 BP      TCS 215  TH 702  EM 0
3265 km/s     Armour 5-43     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 5     PPV 53.46
Maint Life 2.53 Years     MSP 447    AFR 160%    IFR 2.2%    1YR 97    5YR 1457    Max Repair 87.75 MSP
Intended Deployment Time: 9 months    Flight Crew Berths 29    
Hangar Deck Capacity 1000 tons     Magazine 150    

234 EP (26HS) Ion Drive (3)    Power 234    Fuel Use 21.63%    Signature 234    Exp 7%
Fuel Capacity 200,000 Litres    Range 15.5 billion km   (54 days at full power)

Twin 15cm C3 Ultraviolet Laser Turret (6x2)    Range 0km     TS: 6000 km/s     Power 12-6     RM 4    ROF 10        0 0 0 0 0 0 0 0 0 0
Gas-Cooled Fast Reactor Technology PB-1 (7)     Total Power Output 31.5    Armour 0    Exp 5%
This design is classed as a Military Vessel for maintenance purposesThe increase in engineering space is pretty much equal to the reduce in space for fuel so the cost end up the same as if you used six engines but total fuel usage drop somewhat.

As I proved with the designs I showed you, using the less powerful engine will produce a cheaper ship with lower speed and fuel usage while a higher power engine produce a slightly more expensive ship that use up more fuel but also is faster. Those ships that don't need to be super fast get cheaper engines since it also saves me research and fuel.

In general I use *0.75 to 1.25 for standard ship engines. Higher engine power are only made for smaller ships such as corvettes, gunboats etc...

I also believe we play very different games, most of my games revolve around 6+ factions that start in Sol with no AI guiding them... that makes each faction having to compete furiously from the start in all respect. It also means that researching new engine types are mainly fitted to stuff like missiles, fighters and smaller ships first, often larger ships are only refitted every second generation of engines because it is such huge investment to do so, that means the navies can easily have at least three generation of engines on their fleets at any one time.

You can't ever wait and upgrade all the ships all the time, there are neither time nor resources to do so... That is also what I mean, there are many constraint for how and what you build. In a heavy RP environment you can also be restricted by political policies on what you can or can't build or research. But these are of course beyond what is optimization in a mathematical perspective.

Are you in shortage or have an abundance of Gallacite, this is of course important on your overall engine design philosophy.

But the conclusion is that if you build an engine with less power you will save research time, fuel and get safer engines but sacrifice in total speed on your ships. More fuel hungry ships means you will have to invest more into your fuel producing capacity which also cost money and resources out of your total budget, so such strategies will produce overhead in other areas not directly related to the ships, these factors can be hard to calculate and say for sure how really expensive those ships are.

[alex_brunius]

i would like to discuss it based on your design. but since you refuse to do so, i assume you already had a look at it and saw that i'm right

I did post pretty much complete designs with all relevant statics already but you mostly dismissed them for containing "just speeds"...

But sure here are no less then 3 complete designs for you to look at. The design requirements was a minimum of 8 billion km range ( since the jump point furthest out is 4b km away ) and 10% ( 4 layers ) armor.
No matter how I tried I cannot get your strategy to work for my combat designs at all.


(A) Is the one I use in my current game.
(B) First attempt at redesign just adding more engines retaining mission tonnage ( ended a total failure being slightly slower despite 2000 ton heavier 50.4% engines and less Maint Life, and actually more expensive then the first )
(C) Second attempt at redesign using bigger more fuel efficient engines instead trying to retain total tonnage ( didn't end well either since 600 ton of weapons and 100 ton of reactor had to be cut, or half of the secondary armament )

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Orion (A) class Destroyer    5 000 tons     175 Crew     962 BP      TCS 100  TH 504  EM 0
5040 km/s     Armour 4-26     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 2     PPV 30
Maint Life 2.7 Years     MSP 240    AFR 100%    IFR 1.4%    1YR 47    5YR 706    Max Repair 96 MSP
Intended Deployment Time: 12 months    Spare Berths 1    

Arai Heavy Industries 168 EP Ion Drive (3)    Power 168    Fuel Use 125.23%    Signature 168    Exp 14%
Fuel Capacity 350 000 Litres    Range 10.1 billion km   (23 days at full power)

Yoshinobu Space & Security 15cm Railgun V4/C3 (2x4)    Range 120 000km     TS: 5040 km/s     Power 9-3     RM 4    ROF 15        3 3 3 3 2 2 1 1 1 1
Yoshinobu Space & Security 10cm Railgun V4/C3 (6x4)    Range 40 000km     TS: 5040 km/s     Power 3-3     RM 4    ROF 5        1 1 1 1 0 0 0 0 0 0
Futabatei Space & Security Fire Control S00.6 32-5000 (1)    Max Range: 64 000 km   TS: 5000 km/s     84 69 53 37 22 6 0 0 0 0
Futabatei Space & Security Fire Control S02.5 128-5000 (1)    Max Range: 256 000 km   TS: 5000 km/s     96 92 88 84 80 77 73 69 65 61
Shobo Engineering Gas-Cooled Fast Reactor Technology PB-1 (3)     Total Power Output 27    Armour 0    Exp 5%

Fumihiko Limited Active Search Sensor MR2-R1 (1)     GPS 32     Range 2.6m km    MCR 279k km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes

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Orion (B) class Destroyer    6 950 tons     189 Crew     966.8 BP      TCS 139  TH 672  EM 0
4834 km/s     Armour 4-32     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 2     PPV 30
Maint Life 1.86 Years     MSP 174    AFR 193%    IFR 2.7%    1YR 64    5YR 958    Max Repair 96 MSP
Intended Deployment Time: 12 months    Spare Berths 1    

Arai Heavy Industries 96 EP Ion Drive (7)    Power 96    Fuel Use 30.91%    Signature 96    Exp 8%
Fuel Capacity 120 000 Litres    Range 10.1 billion km   (24 days at full power)

Yoshinobu Space & Security 15cm Railgun V4/C3 (2x4)    Range 120 000km     TS: 4834 km/s     Power 9-3     RM 4    ROF 15        3 3 3 3 2 2 1 1 1 1
Yoshinobu Space & Security 10cm Railgun V4/C3 (6x4)    Range 40 000km     TS: 4834 km/s     Power 3-3     RM 4    ROF 5        1 1 1 1 0 0 0 0 0 0
Futabatei Space & Security Fire Control S00.6 32-5000 (1)    Max Range: 64 000 km   TS: 5000 km/s     84 69 53 37 22 6 0 0 0 0
Futabatei Space & Security Fire Control S02.5 128-5000 (1)    Max Range: 256 000 km   TS: 5000 km/s     96 92 88 84 80 77 73 69 65 61
Shobo Engineering Gas-Cooled Fast Reactor Technology PB-1 (3)     Total Power Output 27    Armour 0    Exp 5%

Fumihiko Limited Active Search Sensor MR2-R1 (1)     GPS 32     Range 2.6m km    MCR 279k km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes


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Orion (C) class Destroyer    5 100 tons     144 Crew     772.75 BP      TCS 102  TH 510  EM 0
5000 km/s     Armour 4-26     Shields 0-0     Sensors 1/1/0/0     Damage Control Rating 2     PPV 21
Maint Life 1.79 Years     MSP 189    AFR 104%    IFR 1.4%    1YR 73    5YR 1098    Max Repair 108.375 MSP
Intended Deployment Time: 12 months    Spare Berths 0    

Arai Heavy Industries 255 EP Ion Drive (2)    Power 255    Fuel Use 24.98%    Signature 255    Exp 8%
Fuel Capacity 70 000 Litres    Range 9.9 billion km   (22 days at full power)

Yoshinobu Space & Security 15cm Railgun V4/C3 (2x4)    Range 120 000km     TS: 5000 km/s     Power 9-3     RM 4    ROF 15        3 3 3 3 2 2 1 1 1 1
Yoshinobu Space & Security 10cm Railgun V4/C3 (3x4)    Range 40 000km     TS: 5000 km/s     Power 3-3     RM 4    ROF 5        1 1 1 1 0 0 0 0 0 0
Futabatei Space & Security Fire Control S00.6 32-5000 (1)    Max Range: 64 000 km   TS: 5000 km/s     84 69 53 37 22 6 0 0 0 0
Futabatei Space & Security Fire Control S02.5 128-5000 (1)    Max Range: 256 000 km   TS: 5000 km/s     96 92 88 84 80 77 73 69 65 61
Shobo Engineering Gas-Cooled Fast Reactor Technology PB-1 (2)     Total Power Output 18    Armour 0    Exp 5%

Fumihiko Limited Active Search Sensor MR2-R1 (1)     GPS 32     Range 2.6m km    MCR 279k km    Resolution 1

This design is classed as a Military Vessel for maintenance purposes


Second redesign (C) I guess is a bit closer to something usable since it was a bit cheaper at 773BP which is 80% the price of the original design, but on the other hand it only carries 70% the gun tonnage so it is going to end up more expensive to bring the same amount of guns anyway. If the original design only had two engines it could also be a bit more cheaper ( due to high fuel eff = lower power mod ) and save a few % on fuel giving it an even bigger advantage.



For the bigger ships that are used more for power projection like big Carriers yes, something closer to (C) design would probably be used, even if 45-50% engine is excessive, I would probably still devote 30-40% tonnage to engines and make the ship slower instead. But I also use my biggest Carriers like a kind of forward base carrying loads of extra fuel and munition for other ships, so it kind of already proves my point that your approach is more suitable for civilian or "non combat" ships