Fuel conservation

[mike wightman]

I posted this elsewhere as a several times edited post so I thought I'd put the full version here as well to make it easier for people to comment, or not

I sometimes use a house rule where the power plant of a ship is run at a lower rating during cruising than during combat, weapons training, etc. It costs you hours or days of endurance when you switch everything on though.

This comes from MT days when power plants were so thirsty you would use every possible "rules interpretation" to lower fuel tonnage. IIRC it was originally presented in optional rules for High Guard in a JotTAS article. MT/DGP went one step further by having multiple power plants(one for ship systems on all the time, one for agility, one for weapons, etc) with different fuel durations depending on how many are on.

Take the standard design scout/courier with an upgrade to a TL13 power plant. Same tonnage, 2 more EPs(for a total of 6) to power two lasers, say.

Does it need agility 2 for the full four weeks? If not, then why can't you turn the power plant down to conserve fuel? The same question can be asked for weapons and screens.

You are already paying 2 EPs per round to get 2G movement/acceleration, what you are losing are the AC and initiative bonuses for the agility of 2(which are lost anyway if you install two lasers without uprating the power plant).

If you accept powering down then you could keep the 4t fuel tank, which should last you 6 weeks of maneuver at 2G and two jumps or 8 weeks maneuvering(you'd need to stock up on more food etc).

Enter combat and suddenly you are using fuel at three times the rate. So each day(?) in combat costs you three days endurance.

Military ships with high agility and multiple weapons and screens, with sufficient life support and stores, would be able to cruise for several months in normal space between engagements in a power saving(and lower emission) state.

Just a (resurrected) thought.

Any comments?

 

[The Oz]

I've often thought that ships shouldn't use up their powerplant fuel so fast but figuring out how to keep track of it was enough to make me just forget about it. Fuel supply was very rarely an issue in my games, anyway.

Now, for a TCS campaign, it could be more important.

 

[mike wightman]

Thanks for that Thrash

Where did you get the [per 100 tons of ship] factor from? Is it to convert the book 2 fuel formua to HG/T20?

 

[mike wightman]

So it does, thanks again, I missed that one

That's quite a change to the fuel formula in Book 2 isn't it?

Consider a 100t scout/courier. It has 20t of power plant fuel. Using the Beltstrike formula it would use 0.75t of fuel per week giving it a duration of 26 weeks!

Now consider a 1000t ship with pp K(2) and md K(2). It also has 20t of power plant fuel according to book 2. It uses it 10 times faster than the scout so it only has an endurance of 2 weeks and 4 and a bit days.
As I said, a bit of a change from book 2.

Still, hardly surprising from the supplement that gave us maneuver drives protect against radiation and small meteorite impacts

 

[mike wightman]

Another thought.

You could build a ship with maneuver 6, agility 0. During combat operate your m-drive at 3G and get agility 3(AC and initiative bonus)

 

[clair_rand]

I've worked along these lines for a while, its amazing just what extra performance you can manage. The trick is to split the power column of your design into a few operating modes, then pick your endurance for each mode. work out how much fuel your plant eats per MWh and away you go.. fuel capacity required.

Gets easy if ya does it on a spreadsheet. of course designing the sheet to auto-calculate that gets a bit more complex..

i've got one somewhere that can handle multiple power plants etc. but only a single hull section. i want multi-sectional hulls (different armour) so i never finished it.

Needs a database....

*some day* i'll do one.. have to find a way of doing it at work i reckon