Alternate Ship Design Systems

[robject]

Howdy there,

How many folks out there have tried writing their own starship design rules, or tweaking an existing ruleset into unrecognizability?

I'd like to hear the collected wisdom from these people; what they wanted, what they tried, and what they learned in the process.

My current musings are about jump drives: we know that the real penalty in having a jump drive is in price and fuel requirements -- which is fine by me. I was wondering if it would simplify ship design if the jump drive itself were not especially large. For instance, suppose there is only one jump drive size, and cost is some base amount plus 10% of the fuel requirements (for 'jumpgrid calibration' or something):
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> Tons Jump Rating Base Price (MCr)
10 1 1
10 2 2
10 3 3
10 4 4
10 5 5
10 6 6</pre>[/QUOTE]For a 100 ton ship, the fuel required for a jump-2 drive is 20 tons; the cost of this jump drive is therefore MCr4. A jump-6 drive for this craft would cost MCr12.

For a 400 ton ship, a jump-1 drive takes 40 tons of fuel, and costs only MCr5.

For a 300 ton ship, a jump-4 drive needs 120 tons of fuel, and costs MCr16.

This is untested. Opinions?

 

[far-trader]

Well about all I "bent/expanded" was the Standard Hull/Standard Designs rules in CT Book 2:

To make things "scale" better and allow Far-Trader upgrades to fit in the Standard Hull Free-Trader I altered the Main/Drive split for two hulls. The 200T Standard Hull became 175T/25T Main/Drive and the 800T Standard Hull became 675T/125T Main/Drive. The major effect of this was that 10T of the Free-Trader cargo hold was "lost" making it more relient on speculation, unless... the Captain chose to flaunt regs and carry some small cargos spread around in the unused 10T in the Drives section (where it might be damgaged by or damage the drives, or just result in a fine if caught and the SPA was feeling forgiving

)

The Standard Hull prices were also adjusted so there was more incentive to use them. Basically all standard hulls were changed to reflect a 60% discount (before the whole standard design 10% discount). Also to be allowed the 10% discount for a standard design you had to use a Standard Hull. This did of course affect some of the "standard design" costs a little.

Standard Hulls were also limited to half the normal allotment of hardpoints if small craft were part of the design. This plays against the lower price and gives a further rational for the standard desgins that only have half the allowable hardpoints.

And finally Standard Hulls did not include fuel purifiers even when streamlined (which includes scoops) or armor, but Custom Hulls did (and were classed as Naval Hulls as per the misjump rules in Book 2) even if not streamlined (and so no scoops). The minimal armor amounted to a simple +1 defense bonus. I just did away with the notation of the Scout ship bonus of +2 for misjumps and classed it as a Naval Hull (a cool side effect being that all those antique Type S's converted to Seekers were just a little cooler

)

Other than that I also allowed a bigger computer software budget for all designs. To the tune of programs equal in value to the installed computer. For example if your ship has a Model 2bis computer (worth Mcr18) it comes with your choice of programming, up to Mcr18 in total.

 

[far-trader]

Hmm, I'm not sure I'm getting your idea clearly. Let me know if I'm close.

The cost of the "jump drive" is:

[(hull T/100) + 1] x Base Price by J# on the table.

The "size"* of the "jump drive" is:

??? (always the same no matter the size of the hull? like Black Globes?).

Fuel required is calcualted as:

[(hull T/100) x J#] x 10T from the table.

Am I missing anything?

What are your ideas for power requirements for this system?

* I am after many years starting to think its always been weight not volume that was originally called tons in CT, but that's another issue

 

[mike wightman]

Originally posted by robject:
Howdy there,

Hello robject.

How many folks out there have tried writing their own starship design rules, or tweaking an existing ruleset into unrecognizability?

I got back into Traveller about a year ago because I was doing this very thing.
I was looking for "the ideal ship design" system for a Reality Dysfunction based sci-fi game and started with Alternity. I then started going though my old Traveller stuff and...

As for tweaking, I'm now a big fan of the T20 ship design system (but not their ship combat system). I do the following to it though:

Swap the tables for jump drives and maneuver drives (goes back to LBB2 having big jump drives and small maneuver drives).

Continue the progression to get maneuver drives/agility up to 10G (but keep acceleration compensators limited by TL like in TNE/T4)

Fuel for a fission power plant lasts 10 months per ton.

Power plants are routinely operated at reduced capacity (no need for agility or power to weapons/screens most of the time) so I only build in enough fuel for 1 months duration at the reduced rating. Combat costs hours or days of fuel (can be interesting - "Captain, if we stay in combat much longer we won't have the fuel to jump home".)

Adapt the very high TL weapon systems and jump fuel reduction from MT to T20.

Adapt the modules/systems from GT Starships

Halve the size of weapon bays and reduce spinal mounts by a factor of ten in order to keep a "smallish" ship setting

My current musings are about jump drives: we know that the real penalty in having a jump drive is in price and fuel requirements -- which is fine by me. I was wondering if it would simplify ship design if the jump drive itself were not especially large. For instance, suppose there is only one jump drive size, and cost is some base amount plus 10% of the fuel requirements (for 'jumpgrid calibration' or something):
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> Tons Jump Rating Base Price (MCr)
10 1 1
10 2 2
10 3 3
10 4 4
10 5 5
10 6 6</pre>

For a 100 ton ship, the fuel required for a jump-2 drive is 20 tons; the cost of this jump drive is therefore MCr4. A jump-6 drive for this craft would cost MCr12.

For a 400 ton ship, a jump-1 drive takes 40 tons of fuel, and costs only MCr5.

For a 300 ton ship, a jump-4 drive needs 120 tons of fuel, and costs MCr16.

This is untested. Opinions? [/quote]Would this not give large warships even more space for larger power plants and more armour?

Any thoughts about keeping EP requirements?

(And by the way, how do you format tables like the one above, when making posts. What does the (Code)(/code) thing do?)

 

[Drakon]

One thing you want to consider when you mess with the drive specs is how that will affect the universe you play in.

Traveller 2300 uses stutterwarp. And stutterwarp can be a lot faster than jump drive. (Doing this from a faulty memory core, so bear with me) Seff is measured in lt yrs per day, which times 7 days divided by 3.26 parsec/lt yr will give you the equivalent jump number. (I worked all this out on another, earlier thread.)

Anyway, a stutterwarp efficiency of say 4 is a bit over a jump rating of 7! IF all other things were equal.

But stutterwarps need to dump the energy buildup in their stutterwarp fields down a gravity well every so often, so that even if you did have a Seff of 4, you could only go about 7.7 lt yrs before bad stuff would happen to your ship. Unless you orbitted a planet or star for about 40 hours.

Why? To keep the speed of interstellar travel down to a managable level.

Higher speed travel, the universe gets too homogenous. Spinward Marches gets hard to distinguish from the Spica. The entire known space should end up looking rather Vland pretty soon if you have fast ships.

It is too easy for the Empire to dispatch ships to prevent your players from doing anything. It is too easy for the Empire to find you, to send a message to your next waypoint and intercept. And it gets boring a lot faster.

 

[robject]

On Armor

Thank you for bringing up armor. In High Guard Version 1, there was only 'armor/non-armored'; there were no armor levels (I think). If you armored your vessel, then it was up-armored to the highest rating possible for that TL -- which was volume-costly, but there was no pussyfooting around with armor. A partially-armored ship was absurd; either it was made to take a beating or it wasn't. Making either/or choices may have doomed HGv1, but it did force one to prioritize one's goals clearly, and that showed in a craft's design.

I sort of like that idea. In particular, I like the idea that a ship can't be munchkinned: if you choose a strength, it's reflected in a resulting weakness elsewhere. I might try that, too.

The Azhanti High Lightning is a carryover from HGv1. Apparently it can't hold its own against similar ships designed with HGv2.

So, you want armor? OK, that'll take, uh, 20% hull volume at MCr X per ton, and give you a rating of Y instead of the basic Z. Something like that. Perhaps armoring is affected by 'streamlining' and 'airframing' as well, to allow a couple of minor armor upgrades as well. I suppose that means ships which would never attempt a landing on a T-norm world (like a 20,000 ton cruiser) could nevertheless be airframed for a little boost in armor rating. What the heck.


On Jump Drives

I figure jump drives are, what, a few percentages of the hull size in later versions of Traveller. Well, who cares about that bookkeeping? The big expense is in the fuel tankage required.

So I said to myself, self, what if jump drives themselves were of a standard displacement? Just a funky black box -- perhaps to sit next to the black globe. How much space would that free up?

More importantly, can that space be gobbled up by making power plants a bit bulkier?

A bit more detail. If a jump drive normally takes 5% of a ship's volume, that's 50 tons for a 1000 ton vessel, and 5 tons for a 100 ton vessel. Now, a 10-ton jump drive is going to inconvenience the smaller vessel more, but the 1000 ton ship only gets 40 tons back -- okay, that's significant (4%, right?), but I've noticed that the bigger ships are, the faster the tonnage gets gobbled up in extras. So 40 tons more for a 1000 ton ship might not bother me much. Likewise 490 tons in a 10,000 ton ship. 490 tons is impressive -- that's a wing of fighters -- but we're talking big ships anyhow: we've already gotten away from the Tramp Freighter or Ronin Mercenary group. We're talking fleet actions with 10,000 ton ships, or large-scale trade networks. Big business. I'm not worried at all about 4% of space there; it will be coveted and used, but that's okay by me.

So, yes, I think making the jump drive a percentage of a ship's hull may be add unnecessary complexity -- but only because the fuel requirements are an order of magnitide (or two) greater than the drive's size.

The Burrito Principle applied

And I think that's my point. Starship design should probably only deal with first orders of magnitude -- I think. I could be wrong. But I notice that having more than one significant digit for values usually adds little or nothing to the richness of a design system and adds needless complexity. And the jump drive appears to be another example of needless complexity. Again, I might be wrong.

Accessorize, accessorize

On the other hand, what does make ship design interesting is having to choose components wisely, fitting them into a hull, making choices and compromises based on your priorities, and having a wide range of accessories and tech levels to pick from.

Is this just my own ramblings? Anyone else out there appreciate what Book 2 did right (despite its painful limitations)?

On the other hand, I'd have to say power plants and maneuver drives have to scale with hull sizes; but then all ship design rules do that, some simplistically, some overcomplicatedly[sic]. What are power plants, (1+rating)% at MCr 4 per ton? Something like that? Ach, I don't remember EPs, one per ton, appx 250 MW per EP? And maneuver drives? Ah well, but it's late. Maybe I'll think about it tomorrow.

 

[Drakon]

Having no idea what the Burrito principle is, thought I would put in some more cents (If not sense)

One of the things that has been buzzing in my head is an attempt to convert to a warp drive system. This is because I see warp drive as more feasible now, since Alcubierra's paper. I see how that would work, whereas I am not sure that jump drive is. (I know this is a reversal of the situation from when CT was invented, back in the 70's. That's science for you. Always screwing up the science fiction.)

[Note: Ideally, I hope to come up with a drive system that differs from Traveller Jump Drive in technobabble primarily. A few details (no misjumps, but what else to replace it?) would be changed, but from a game mechanics perspective, it should be very little different]

But remember, while we may like to imagine these are real ships and on one level this is all make believe, we still need things that will not screw up the game. Not change the character or nature of the setting we are playing in. Altering the jump drive displacement numbers can have far reaching effects, and some of them are not going to be what you expect or intend. So tread carefully and slowly.

As a first glance, reducing the drive displacement means freeing up more space for other things. One thing will be fuel, which will make refueling less an issue (relatively speaking) This means, depending on exactly how you do it, that your ships will be able to more cargo further and faster than otherwise. What is the ripple effect from that?

It is going to change your empire's economy. How significantly depends on how much of a change it is. And can lead to a more homogenized empire, with something like the equivalent of McDonald's at every starport. Also it means that imperial forces would find it easier to track you down and capture you.

Having said all that, I would recommend coming up with the whys and hows for your drive system first, then figuring out how that affects displacement and power requirements. Does a 10 ton drive, used to move a 100 ton ship, move a 1,000 ton ship in exactly the same manner? Scaling drive system with hull size, (even if not to the extent that Traveller does) does make some sense. Bigger ships with small engines, at least superficially appear that they would move slower. But again that depends on your technobabble explaination of how the drive works.

It seems to me that as Tech Level goes up, Drive system size should shrink, for the same performance. Speed and fuel efficiency (which may be different ways of measuring the same thing) should track with tech level.

As to power plants, and manuvering drives, here it gets tricky. If your power load tracks with hull size, then obviously your power plant has to track with hull size. But this is not necessarily true. An armed warship has a lot greater power demand than a cargo ship.

Also, it kind of depends on how your drive system works. You can think of the drive as being its own power generator, or separate power generation from propulsion, have these as separate systems and see the propulsion system as more a converter than generator. If you do the latter, then comes the question of whether your 10 ton drive can handle the increase in power required to move a 1,000 ton ship.

Manuvering drives kinda confuse me. I would like to see this as part of the standard ship's drive. My experiences in the real world navy makes me think of manuvering drive as a very small, well equivalent to an outboard motor for very fine and slow motion. But that is me.

 

[jwdh71]

I change the fuel requirements in my Traveller games all the time. I don't do so in the OTU though, as it would change a lot of the background.

In my current campaign, the fuel requirements for jump are 1% of the ships tonnage in fuel per jump number. I also use standard designs, so it means that a normal ship has fuel for 10 jumps. I also multiply by ten the number of weeks the standard load of power plant fuel will last, from 4 to 40 weeks. Add to this the fact that I shorten time in jump from 160 hours to around 80, changes things a bit.

The changes make others things possible, like free traders that are able to make money, due to the decrease in fuel costs, and not all systems are colonized, only high resource systems and garden worlds get significant populations. It also means that inhabited systems get farther apart, making deep space jumps and empty transit system jumps necessary. This gives me justification for piracy, as there are places that aren't populated or heavily patrolled that see significant merchant traffic, especially in frontier subsectors.

When we first played Traveller (oh so many years ago), we developed a alternate design system that meshed into an alternate ship combat system. It was substantially modified from LBB2 and HighGuard2, and had the interesting idea that you could make the size of weapon you wanted, i.e. not everything fit into standard turrets. You had missile and laser spinal mounts, large turrets sporting meson guns, and other crunchy goodness. I'll have to see if I can find any notes I may have on it, and post them.

 

[Straybow]

The only things I see worth changing are (in rough order of precedence):

1. Consistant mass and volume standards (see my rabble-rousing threads );
2. Jump Drive game mechanism from "always one week ±10%" to something else that doesn't seem so contrived (and if stutterwarp is too fast, slow it down without leaning on a mechanism that is equally contrived);
3. Fuel/energy requirements (how the heck can fusion require more fuel than fission? —see my other rabble-rousing )

I guess one of these days I'll have to rouse some rabble about Jump tech, but that isn't something to which hard science lends itself the way basic mass and energy physics.

 

[snrdg082102]

Call out the bad pun police

.

The entire known space should end up looking rather Vland pretty soon if you have fast ships.

Better yet call the guys with the I love me jacket.

Originally posted by Drakon:
One thing you want to consider when you mess with the drive specs is how that will affect the universe you play in.

Traveller 2300 uses stutterwarp. And stutterwarp can be a lot faster than jump drive. (Doing this from a faulty memory core, so bear with me) Seff is measured in lt yrs per day, which times 7 days divided by 3.26 parsec/lt yr will give you the equivalent jump number. (I worked all this out on another, earlier thread.)

Anyway, a stutterwarp efficiency of say 4 is a bit over a jump rating of 7! IF all other things were equal.

But stutterwarps need to dump the energy buildup in their stutterwarp fields down a gravity well every so often, so that even if you did have a Seff of 4, you could only go about 7.7 lt yrs before bad stuff would happen to your ship. Unless you orbitted a planet or star for about 40 hours.

Why? To keep the speed of interstellar travel down to a managable level.

Higher speed travel, the universe gets too homogenous. Spinward Marches gets hard to distinguish from the Spica. The entire known space should end up looking rather Vland pretty soon if you have fast ships.

It is too easy for the Empire to dispatch ships to prevent your players from doing anything. It is too easy for the Empire to find you, to send a message to your next waypoint and intercept. And it gets boring a lot faster.

 

[savage]

I've made a few changesv in MTU;
1. TL16+ improves plant efficiency and reduces jump fuel requirements to 50%.
2. I also have limited supplies of the CT high-quality fuel that allows 1/2 the jump fuel being needed.
3. JumpGates with tiered jump capability J1-36
4. Low Maintenance and High Performance Drives from MT.

Savage

 

[csmith]

My adventures that take place on the solomani rim I use stutterwarpships. I've applied the a few limits to make them fit in better.
1 Stutterwarp is limited to an effective jump 3. This makes the ship a more of a sprint ship then a long distance craft.
2. the coils must be cleansed in a gravity well for a week. standard whole over from 2300:AD
3. +5 to sensor tasks detecting a stutter warp ship. just plays hell with sensor packages

Those are my mods.

 

[Michael Taylor]

Reducing the "10% of ship size per Jump range" rule means Trav ships can be packed to the gunnels with all kinds of shite (max armor, massive powerplants, legions of troops/fighters etc etc etc) so having the jump fuel rule firmly fixed avoids superships IMHO. Thats why I like High Guard/T20 ship design.

 

[Straybow]

Well, you can use a fission power plant in MT or T20 (see here) and (as absolutely absurd as it sounds) reduce the fuel requirements and make room for more stuff.

To me, that just goes to show the fuel requirements are broken, at least from the power standpoint. Somewhere there is an explanation that jump requires a plasma bubble around the ship, for which you need all those dT of hydrogen.

 

[mike wightman]

If you compare the fuel used by a vehicle fission reactor with a starship fission reactor you will find that one or the other is broken. Complicated maths aside, the ship scale fission reactor's fuel should last for 10 months per dt per fission unit (well, 40 weeks ), a much more accurate reflection of the real world.

It's swings and roundabouts though because a fission reactor plus its months of fuel will be a similar size to a fusion reactor of similar output, it just doesn't need refueling as often.

The jump bubble requiring hydrogen plasma is a good way to explain the "fuel" requirement of the jump drive.
At TLs above 16, MT reduced the jump fuel requirement
17 - 80% of calculated jump fuel
18 - 60% of calculated jump fuel
19 - 40% of calculated jump fuel
20 - 20% of calculated jump fuel
21 - 10% of calculated jump fuel

 

[jwdh71]

Michael Taylor wrote:

Reducing the "10% of ship size per Jump range" rule means Trav ships can be packed to the gunnels with all kinds of shite (max armor, massive powerplants, legions of troops/fighters etc etc etc) so having the jump fuel rule firmly fixed avoids superships IMHO. Thats why I like High Guard/T20 ship design.

Well, it's Traveller, but it isn't always the way you see ships working in other SF. When I first started playing Traveller (in the late 70's), I based my campaign on SF that I had read, and movies and TV shows that were out at the time. The jump fuel requirements that Traveller had at the time were extreme in comparison, meaning that you couldn't emulate the SF fiction of the era. So we changed it, in some cases, for some game universes, it was a modification of the jump fuel rules, for others, jump fuel was done away with, the j-drive being powered by the power plant. Other times we changed the jump drive altogether, making it a warp point drive, or even a warp drive. At the time the OTU wasn't fully formed, so Traveller as a game was much wider open, you could tweek it to your satisfaction.

I still do that today, preferring to run in a more open game universe. The OTU, and the Third Imperium in particular, gives you very little room for frontier style games, being almost completely surrounded by other large (if not quite as large as the 3I) polities. One of the few places this is not quite so bad is the Gateway Domain, which is why I'm looking forward to the release of the sourcebook so much. But even there, the non Imperial systems have been explored, colonized, and exploited for long periods of time. The OTU is vast, but fairly crowded, and I prefer the wide open emptiness feeling you get when all known civilization is behind you, and ahead of you is the unknown.

 

[Straybow]

Solution to superships: make jump drive nonlinear. The present system has jump drive proportional to volume. Make a component of the equation some higher order (nlogn, n², expn) with the explanation that jump bubble stability decreases with size, etc.

 

[Drakon]

There is something called "pump laws" that I think might work and at least give the feel for reality, (if not reality itself)

(mumbles, where is it? )

As you double the speed of a pump, the flowrate doubles, the pressure on the output goes up 4(2^2) fold, while the power required to get it that fast goes up 8 fold. (2^3)

So...Making it nonlinear would have its advantages. Power requirement, it seems to me, would be linear with fuel consumption. You can go really really fast, but only for shorter amounts of time. The faster you go, the more you guzzle fuel.

 

[TKalbfus]

One substitution I'd like to make is to substitute rocket engines for maneuver drives. A Rocket engine sips power plant fuel instead of EP from that power plant. Fusion rockets come in 6 varieties, but instead of g-ratings rocket units produce 50 tons of thrust. A TL16 Fusion rocket would for instance take up 1 ton, and sip 1.7 tons of fusion fuel per hour. In the meantime you can use the full powerplant output for weapons systems since the rocket units require no power inputs, only fuel inputs. You divide the tonnage of the ship by the thrust produced by the rocket units, and that is the ship's acceleration. The ship's displacement is assumed to approximate its mass.

 

[Flynn]

tjoneslo would be the man to consult for that one. I seem to recall that he did say something about looking into something along those lines.

Of course, I could be mistaken, and if so, I apologize,
Flynn