Workaround for energy consumption in starships:

[captainjack23]

Excellent suggestions all ! I had a feeling there was life in the old thread.

Some thoughts:
The scaling in the drive table is intentionally non linear - it was designed by engineering types for two reasons: to reflect the actual preformance characteristics of powerplants (which vary in efficiency and lifespan based on load) and to let the players have some hard decisions which cant just be minimaxed. Yes, it can be made linear, but it isn't; so the system is designed to take that into account. Its a local correction factor as much as anything -I admit the system probably breakes when designing hulls significantly outside of the hull ranges for the core rulebook -a nd probably not at all for small craft.

I honestly don't remember why I stayed away from power points -but I think it had more to do with producing a backwards CT compatable allocation system, that was role/gameplay friendly.

And yes, classic traveller HG is an elegant system for power, but the drives and building rules are quite different -some would argue incompatable....


As to the life support, yes, that could one way to break it down - on the other hand, my assumption is that non-grav life support power consumption is trivial compared to weapons and M drive, and possibly, to a lesser extent, sensors. YMMV, obviously, since that is one of the areas (in CT and MGT) that is up to the conscience of the individual

Do note that turning off grav will effect the compensation system, and cause big problems for the crew when maneuvering at traveller M drive levels. No floating around if you are making 3G vector changes......

 

[captainjack23]

I'm not sure multiplying the power plant rating by the hull size makes sense. It should be a flat number of power points per power plant rating, with the other drives consuming a flat amount per their rating, surely?

Looking over the suggested rules, I really can't find where you see the power plant is multiplied by hull size. Am I missing somthing ?

The output of a plant is what it always was in the drive table +2 . - ie a type A powerplant in a scout has a rating of of 2 (its rating from the table) and its output is that plus 2 to represent the demand for life support & internals as well as the average demand of the weaponry.

The weaponry demand is simply the average demand per hardpoint; if you have more hardpoints, you have a bigger hull and a bigger powerplant. The goal was to make the weapons systems an equal choice factor along with the M drive and J drive, really...or one can buy it off the shelf with a basic loadout and not worry.

My assumption was that for a given off the shelf hull/power plant pairing, the powerplant would move the hull at its stated M rating and fire some basic loadout of energy weapons. The last bit is the arbitrary part - IIRC I assumed that a basic civilian legal turret would have a demand of 1.0, and defined it as either one beam or two pulse plus whatever non-power guzzling weapons you wanted or had room for.

So, if you want to over arm a ship, one can either use averaging to meet the demand (1 particle beam turret plus 4 missle/sandcaster turrets /5 = demand of 1.0, no sweat, but you'll need a 500 ton ship to do it) or upgrade the powerplant to more than the drives need.


Now, admitted, the life support doesn't scale at all for the size of the ship, but there is where my assumption that it's a trivial expense comes into play;I just assume that keeping 1G environment and gravitic compensation is essentially the same for ships in that size range and takes up 99.9% of the power of that single point.

If you wanted to quantify it it could be related to the ratio of a ships volume divided by the max volumetric tonnage in the core book hulls (2000 ?) - so it would be somewhere around 1.0 to .05 for a scout ; and while that is quite a range, I was willing to accept that lack of scaling for 1 point for the sake of simplicity.


I guess its not so much a design system as much as it is a modification system.......

'cause I just have to fiddle, I've added a few things to the original, noted in blue.

 

[phavoc]

While its easier to assign energy on a per-hardpoint basis, I think it would be better to assign power consumption on a per-weapon basis.

Power plant energy minimums should be organized around life support (air and internal grav plating), engineering (doors, sensors, lifts, but excluding thrust), then maneuvering (starting at minimal, 1G in this case), and then whatever left over could be dumped into weapon systems.

A fusion plant could I guess be downgraded to minimize fuel consumption, and therefore lower output. As well as running it at redline for additional power output in emergencies. In the Honor Harrington series, the military ships typically run at like 80% of their normal thrust capabilities, with a healthy 20% in reserve. But in combat or when speed is required, they can go to their 'military' maximum. The closer you get to your maximum, the higher the risk that there could be a catasropic failure that could lead to bad consequences. They also sometimes exceed the 100% maximum on systems by removing safety interlocks. Which makes sense when you are talking about electronics. We do the same thing with adding more power to a CPU to get it running at a higher clock-speed, but there is the risk of burning it out or permanent damage.

It might be easiest to simply apply a baseline power output per ton/whatever of a power plant. This would mean that when a starship was designed, a "minimum" amount of power to turn on lights, activate basic navigational and computer and sensor systems, and be able to generate 1G of thrust would need to be calculated. After that if you wanted to go faster or mount weapons, then you'd need to put in a bigger power plant to accomodate them.

Aannddd, to make rules more fun, you could start adding in things like batteries, or capacitors for energy weapons so that they could be 'charged' prior to combat and not draw power from the main reactor. Kinda like how Megatraveller had the grav tank energy guns able to fire X amount of shots from onboard capacitors, and it could take a while to recharge the capacitor.

I'm thinking that if you went to energy-per-weapon scenarios, more people would have to look at tradeoff of particle beams vs. lasers. And you might see more missile-armed ships to offset energy requirements.

Which gets me thinking I need to finish my VLS missile system design rules. [/img]

 

[rinku]

I'm not sure multiplying the power plant rating by the hull size makes sense. It should be a flat number of power points per power plant rating, with the other drives consuming a flat amount per their rating, surely?

Looking over the suggested rules, I really can't find where you see the power plant is multiplied by hull size. Am I missing somthing ?

No, I think I must have had a brain freeze, or was carrying over from some other topic. The basic system is clean and elegant, and "demand" works better than a pure points allocation would in a roleplaying sense. Ignore my previous post.

 

[captainjack23]

Which gets me thinking I need to finish my VLS missile system design rules. [/img]

No kidding. Quit Goofing Off !

 

[Rikki Tikki Traveller]

If you use the rating from the table, you ARE taking into account the hull size. So when you use Rating+2, the hull size is buried in your formula.

A PP=A has a different rating for different size hulls (2 for 100-tons and 1 for 200-tons).

It should produce the same number of Energy Points for each ship. The 200-ton ship just needs MORE power to accelerate at 1G.

My suggestion is that the PP=A should produce 4 EP.

100 G-tons (1G for 100 tons) takes 1 EP. So 2 EP are needed for the Rating=1 on the 200 ton ship, that leaves 2 EP for whatever.

Here is how your formula would do it:

100-ton ship: EP = 4
200-ton ship: EP = 3

But the same PP is used for both ships, so the EP should be the same.

If you make a PP=A have 4 EP output, then the M-Drive takes 2 EP for each ship and you have 2 EP for life support and weapons. BUT, the 200-ton ship needs more EP for life support (twice as much approximately) so has less EP for weapons (a civilian design). Want more EP? Buy a bigger PP.

So make each PP letter give you 4 EP and it should be OK until you get to the non-linear letters near the end of the table. But if you go back and look at the M-Drive OUTPUT (in G-tons) you should be able to figure out what EP it should have.

 

[captainjack23]

I wrote some comments about the above, then reread your comments, and decided to think some more instead of posting them.

I think you are proposing a simple expansion of the output digits, essentially multiplying it by 4 (1=4, 2=8, 3=12) to add room for granularity ? Is that correct ?

 

[rinku]

Life support should be solely based on crew accomodations, not hull size. Likewise, computer and sensor costs should be based on the computer and sensor ratings.

I don't see any power cost that's going to be affected by hull size alone, except *maybe* jump drive. Even bridge requirements should be based on the bridge size and type, though I doubt the power involved would be a significant fraction of the other systems, and can probably be ignored or considered to be part of the computer cost.

The old High Guard system allocated energy points to weapons, screens and computers, with any remaining points used to power agility (M-drive). Naturally, capital ships have differing requirements, but it's clear that the main energy burners are drives, screens and weapons; life support and even sensors are only going to require a small fraction of a typical fusion plant's output.

 

[PFVA63]

Life support should be solely based on crew accomodations, not hull size. ...

Hi,

Although this isn't necessarily a bad idea I suspect that you could run into some problems. Specifically, it may well be possible to have a small crew on a relatively large cargo vessel, but have the same size crew on a smaller patrol craft. Giving them both the same Life Support costs might not make sense, in that the larger ship may have to be able to provide adeqaute lighting, fresh air, and other facilities throughout any space that the crew might be called on to enter, whereas the smaller ship (with the same size crew) would not need as much power for all that, since there are fewer spaces for the crew to go. Additionally, if the cargo ship is expected to have an enivronmentally controlled cargo hold (to allow the carriage of a wide variety of cargo types) that would also probably cost some power. As such, it would seem to me that perhaps a power requirement for life support based on both crew number and hull size might make more sense.

Regards

PF

 

[rinku]

I can see where you're coming from, but in practice the hold isn't going to be heated at stateroom temperatures unless it's hauling delicate cargo (and LIVE cargo is going to need extra life support anyway), and lighting would only be needed where the crew were operating (not that lighting is going to be a big overhead anyway compared to temperature control).

Air conditioning is likewise not going to be needed if there aren't any breathers in that compartment. A bigger ship will need more gas reserves and actual lights and heating plant, but the power cost to run it is going to mostly depend on the number of people using it. Think of an office building with automatic lights, heating and aircon that shuts floors down when people have all left, then starts up again when they come in. But more sophisticated.

On a big cargo ship, I think you can assume the crew would prep a compartment for comfort if they have to operate in there for any length of time.

However, if you like, assign an energy cost for cargo space life support.

 

[phavoc]

I would prefer keeping power consumption simple, such as allocating X points of power to life support period. Things like engines would take a great deal of power, as would weapons. Bigger, more powerful weapons would take even larger amounts of power.

So, take for instance a 1000 ton freighter. It would require 1pt of power for life support and ship operations (computer, doors, sensors, etc). For sake of argument, it takes 1pt of power to move 100 tons of ship at 1G, so it would need a minimum of 10pts of power allocated to engines and thrust (this would also cover the anti-grav for landing). Since it operates in a peaceful part of space, its unarmed, thus the total energy requirement is 11pts.

Now, take the same ship, and arm it with 5 hardpoints. Passive weapon systems, such as missile launchers and sand casters can be powered by 1 pt to the entire weapon mount. This would also power any on-mount systems requried for any type of weapon. So that means 5pts of power are allocated to the 5 hardpoints. Now, the remaing 3 hard points each mount a dual laser. To keep it simple, we'll say lasers require 1pt of power EACH. So 3 hard points * 2 lasers per hardpoint gives us 6pts of power. Thus, our armed freighter requires 11pts for movement and operation, and another 11pts to power weapons, for a total of 22pts.

Additional types of weapons, like particle barbettes make take 2pts each, while 50ton mounts could take 20 pts, while a monstrous 100ton particle beam bay might take 100 points.

This keeps it relatively simple, but still allows for you to create power requirements that would add more flavor to your game. Say your players got their hands on some particle beams and wanted to mount them in their 800 ton merc cruiser... but in order to do so they need to upgrade their power plant or remove some laser turrets. Alternatively the referee could allow for all of the weapons to be mounted, but since they would be energy deficient, they can't fire them all in the same round, so they would have to pick and choose which weapons they did want to use each turn. This would undoubetdly inspire their engineering character "Scotty" to find extra ergs of power from his reactor in emergencies, which could lead to interesting and dire consequences. Say your characters just had a great payday and you are wondering how to deplete their funds... a damaged reactor is a great way to go! Or maybe they are having to scavenge for parts to their damaged reactor, etc, etc.

 

[rinku]

Original High Guard has a list of energy point costs per weapon. I could dig that out tonght and post them if you like, to give a baseline.

Some things just won't pull enough juice to be worth recording at this level. My opinion is that if the computer is powered, all of the routine power requirements of doors, missile racks, sandcasters etc are covered. Missiles and such can't operate without tracking anyway (i.e. computer & sensors). The big power requirement for life support will be heating and aircon, but it will be thousandths or millionths of the power required to maneuver or shoot. Ironically, the bigger the ship (and thus the bigger the plant required to maneuver at a minimum of 1G) the smaller the fraction of the available power needed to run life support per crewmember (crew sizes do not generally increase in proportion to the ship size, especially for sub-capitals that don't carry a lot of passengers).

Might be worth pulling out Fire Fusion & Steel to get some comparative kW costs. I could be wrong, but wasn't the standard TNE laser a 250 kW weapon? That'd be enough juice to provide power and light for several hundred houses.

 

[phavoc]

Original High Guard has a list of energy point costs per weapon. I could dig that out tonght and post them if you like, to give a baseline.

Some things just won't pull enough juice to be worth recording at this level. My opinion is that if the computer is powered, all of the routine power requirements of doors, missile racks, sandcasters etc are covered. Missiles and such can't operate without tracking anyway (i.e. computer & sensors). The big power requirement for life support will be heating and aircon, but it will be thousandths or millionths of the power required to maneuver or shoot. Ironically, the bigger the ship (and thus the bigger the plant required to maneuver at a minimum of 1G) the smaller the fraction of the available power needed to run life support per crewmember (crew sizes do not generally increase in proportion to the ship size, especially for sub-capitals that don't carry a lot of passengers).

Might be worth pulling out Fire Fusion & Steel to get some comparative kW costs. I could be wrong, but wasn't the standard TNE laser a 250 kW weapon? That'd be enough juice to provide power and light for several hundred houses.

Well, actually power consumption for internal use is going to include the anti-grav for the deck plating and the inertial dampers along with the computer systems, sensors and a host of other pieces of equipment. Which, I agree with you, pale in comparison to what a energy weapons would use. The reason I mentioned power to the missile systems is that they also require power for the auto-load mechanisms, on-mount systems, etc. It's not totally free, though still not in the arena of what it would take for an energy weapon. That's why I suggested a point to power an entire mount's systems.

I have those books in a box somewhere too. And I do believe you are right about the laser size. I know the GT lasers had varying power capacity, though the design system wasn't too unforgiving in that sense.

 

[rinku]

Yeah... I'd forgotten about the grav plates.

However, their inertial compensation function would be part and parcel of the M-Drive use and power requirements - the juice required will spike every time you do a burn; I'd tend to lump the grav plate power requirements in with the thrust cost, keeping in mind that a ship which *isn't* thrusting has power to spare for the 1G constant field. But, yeah... a flat cost or one based on hull size is not unreasonable, if you like.

Still not convinced that a missile rack and loading apparatus is going to draw a significant power load if you're counting 1 energy point per laser. Old High Guard didn't count 'em and that's good enough for me!

 

[rinku]

Okay, here are the numbers for original High Guard:

A powerplant generates 0.01MPn points where M=ship tonnage and Pn is the PP rating. Note that as the rating of the PP already takes into account the ship tonnage this is a linear relationship with PP tonnage. So a Type/S or a Type/A would both generate 2 points. A 1000 ton ship with rating 3 PP would generate 30 points.

Computers model 1-2 use no energy points, as do black globes, sandcasters and missiles (even 100 ton bays). Computer model/3 uses 1 point, /4 uses 2 points, /5 uses 3 points, /6 uses 5 points, /7 uses 7 points, /8 uses 9 points and /9 uses 12 points.

Both types of lasers and turret plasma guns use 1 point. Turret fusion guns use 2 points and turret/barbette particle accelerators use 5 points. (Note that in OT terms a PA barbette is a TL14 version in all ways inferior to the TL15 PA turret. MGT has redefined this).

Spinal mounts use energy points ranging from 500 to 1200 depending on rating. 50 ton plasma bays use 10, 50 ton fusion bays use 20.

50 ton repulsor bays use 5, 50 ton PA bays use 30, 50 ton Meson bays use 100. Double the costs for 100 ton bays (there are no 100 ton plasma/fusion bays).

Nuke dampers cost 10 points per rating. Meson screens cost 0.2 points per 100 tons of ship per rating.