Fuel Consumption - Theorycraft!

Looking at gamefiles i think i’ve found how fuel consumption work, related to engine power. It was easier than i firstly thougt!

Lights: Light use 1% of a Fuel Barrel per second. Always.

Engine Power: Engine use 5% of total engine power per second. Of course you have to take account of fuel efficiency bonus.

So, let’s say, with starting engine (+800 EP) and Maybe’s Daughter (+100 EP) and lights on, we will use 0,45+1= 1,45% of a fuel barrel per seconds.

With a Compulsion (+3500) and nothing else, we will use 1,75% of a fuel barrel per second, 2,75% with lights on…

And so on.

It looks clear that everything above the Boadicea, without proper reduction (5% from Tireless Mechanic and 10% from Milebreaker) would be VERY expensive.

Do you know how Full power effects fuel consumption rate, or, for that matter, the fuel efficiency bonuses?

Full power it’s just 2X, i think Fuel Efficiency it’s just a multiplicative factor.

So, if you should consume 1% of fuel/sec (2 with full power) with a reducion of 10%, you will consume 0,9%/sec (1,8 with full power).

In any case i don’t have idea of HOW Engine Power affect total speed…
edited by Frenzgyn on 2/12/2015

Something is off about your formula. 1.75% is much, much too low. Compulsion consumes approximately 3.4% of a fuel barrel per second on its own. Starting engine on its own consumes about 0.79% per second.

You are right, however, that it scales linearly with power. I haven’t determined exactly how this relates to the 0.05 figure given in the files, but you can estimate it as power/28.5 barrels per hour.

Something is off about your formula. 1.75% is much, much too low. Compulsion consumes approximately 3.4% of a fuel barrel per second on its own. Starting engine on its own consumes about 0.79% per second.[/quote]
So your results, Gregg, seem consistent with Frenzgyn’s, only doubled.

3.5% of a fuel barrel per second for a 3500-power engine, and 0.8% for 800 power. Assuming no extras, of course.

Seems very neat, even if it puts into question the significance of that 0.05 in the game files.

Well, the measured consumption for 3500 power was closer to 3.35% or so, over three runs, so not double. But…

3.5% has a very obvious relationship to 3500 power, as does 0.8% to 800 power. Not sure why I didn’t see this before (probably because it wasn’t actually 3.5%).

There’s another number in the files related to power, EnginePowerModifier, with a value of 4.5. This might possibly be related?
edited by Olorin on 2/12/2015

One way to figure out what these numbers do would be to change them.

On a different thread, someone mentioned turn rate seemed to be dependent on performance. As in the game’s performance and FPS. It could perhaps be inferred that that 0.15% difference is due to very minor performance fluctuations during the testing period.

I’ve noticed my framerate isn’t always constant, despite having a very respectable PC (for what the game demands).

And my PC is very much not respectable. Hmm.

I’m still on Unforgiving mode, so I’ve been afraid to attempt that. Maybe some time this weekend.

You can find and backup your savegame in:
C:\Documents and Settings(username)\Local Settings\Application Data\Failbetter Games\Sunless Sea\saves\Autosave.json

But there’s also the possibility this isn’t performance-related, but rather linked to the fact you’re presumably not a machine and just made the slightest human mistake when measuring time during the test (starting/halting your stopwatch an instant too early/late). After all, 0.15% is fairly tiny a variance from what’s very likely the intended or at least theoretical value.

I ran the tests multiple times and made them as long as I could stand to minimise the effects of human error. Still I suppose 3.5% is within the bounds of possibility given what I have recorded.
edited by Olorin on 2/12/2015

C:\Documents and Settings(username)\Local Settings\Application Data\Failbetter Games\Sunless Sea\saves\Autosave.json
[/quote]

In fact if you’re modding game values you should always back up the save files (and the files you change) because it’s easy to completely break something.
edited by WormApotheote on 2/12/2015

Well, i was just attending to the numbers in the game files:

“FuelUpdatePeriod”: 1,
“BaseShipSpeed”: 8,
“BaseShipSpeedLimit”: 0.0005,
“ShipReversePenalty”: 0.5,
“EnginePowerModifier”: 4.5,
“BaseShipAcceleration”: 5,
“BaseShipTurningSpeed”: 0.1,
“EngineFuelDecrementUnit”: 0.05,
“LightFuelDecrementUnit”: 100,
“TurboSpeedMultiplier”: 1.75,
“TurboFuelCostMultiplier”: 2,

Considering that standing still with lights on you see an 1% of Barrel usage per second, i came up to 0,05 being 5% of the engine power, since the only quality that engines have (expcept for serpentine and impeller) is that…

Ah. Of course. There is another set of numbers involved here. Throttle setting. At 1 or -1, they will use what you calculated above. At 2 or -2 they use twice that (and move at about twice the speed). Since most people, including myself, are impatient, all my numbers are based on 2-speed.

I didn’t think of this originally because I thought there was a half-speed modifier in there somewhere.
edited by Olorin on 2/12/2015

:facepalm:

You’re right sir! I totally forgot of that!

Sure that’s more expensive per second - but the real expense is per mile (does speed scale linearly with power? If so, there’s no change there, except added difficulty maneuvering efficiently.) And moving faster saves you terror, that lighting cost, and food. And being blown up, which is costly.

No, it doesn’t seem to scale linearly with power, since base ship speed is 8, and is fixed, then you add the increment of Engine.
I’ve not figured yet HOW is calculated, since there are some values that i cannot correlate (Baseshipspeedlimit and Enginepowermodifier).

Weight has an effect as well. It’s most noticeable with the weaker engines, but even the strongest are slowed somewhat by the largest hulls.

BaseShipSpeedLimit might have something to do with this.

I highly doubt there’s any adding of Power as far as Speed is concerned. If I can be permitted to throw out a completely untested speculation, I think BaseSpeedLimit * Weight might be the amount subtracted from BaseShipSpeed, which is then multiplied by whatever the normal MaxSpeed of the Engine would be.

i.e.

(BaseShipSpeed - BaseShipSpeedLimitWeight)(SpeedFromPower) = Effective Max Speed

edit: Running this over my existing data doesn’t produce any useful correlations. So it’s probably not the right answer. Well, I mean… it might be within margin-of-error. But then again the original numbers were already pretty close. It’s impossible to say for sure without knowing what &quotSpeedFromPower&quot is.
edited by Olorin on 2/12/2015

[quote=Gregg Johnson]Ah. Of course. There is another set of numbers involved here. Throttle setting. At 1 or -1, they will use what you calculated above. At 2 or -2 they use twice that (and move at about twice the speed). Since most people, including myself, are impatient, all my numbers are based on 2-speed.

I didn’t think of this originally because I thought there was a half-speed modifier in there somewhere.
edited by Olorin on 2/12/2015[/quote]
Might be Captain Obvious here, but a little tidbit: it seems to be as you say, but reverse speed additionally goes through the ShipReversePenalty multiplier (0.5), which means half reverse equals a hypothetical quarter forward speed, and full reverse is half speed.

[color=rgb(172, 178, 184)]Playing with numbers in gamefiles, i found a couple of things:[/color]
[color=rgb(172, 178, 184)]If I set Baseshipspeed to 0 and use an Engine with EP +0, the ship moves. Slightly. This should be due to &quotBaseshipacceleration: 5&quot, since if i set this to 0, no matter which engine i use, the ship doesn’t move at all.[/color]

[color=rgb(172, 178, 184)]I have a theory, not tested at all.[/color]

[color=rgb(172, 178, 184)]EnginePowerModifier and BaseShipSpeedLimit are correlated, so maximum speed could be:[/color]

[color=rgb(172, 178, 184)]4.5 * EP * 0.0005 + BaseshipSpeed. [/color]

[color=rgb(172, 178, 184)]So, for example, with a Compulsion we have: [/color]

[color=rgb(172, 178, 184)]7,875 + BaseshipSpeed (8), that means a total speed of 15,875 (a 1 throttling), compared to a &quotstarting speed&quot (8 + the starting engine that give 1.8) 9.8[/color]

[color=rgb(172, 178, 184)]This should mean that compulsion give a boost to your speed 1 (not acceleration!) of about 61,7% compared to base engine and that, in the same way the 1000Ep engine gives a 4,6% boost.[/color]

[color=rgb(172, 178, 184)]MAYBE (just maybe) ship weight is taken into account with acceleration… but i have no value to say that… [/color]

[color=rgb(172, 178, 184)]Of course, this is just speculation… can you find any correlation with your existing data?
[/color]