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Heavy Haulers-Big Rigs of Space

Hey, wait, the numbers are okay, but my economics are WAY off. It turns out to be very, very viable for any world with a volume of regular traffic, such as X-Boat systems and 'major' worlds.

Case in point: Tureded, a relatively insignificant world on the Spinward Main, has FOUR class C downports placed along the equator. IIRC, this world has a TL of 8, and not a huge population, either.

If a podunk TL8 world can build four C downports, then (handwave) surely a TL12 world with a class A starport and a population code of 8 can build, place, and maintain some class C freight stations at the 100D limit. How about a formula like this?

Freighter ports = TL + Pop - 16
FP class = main starport class - 2

So, Tureded doesn't have a freighter port. Regina would have 4 class C freighter ports. Rhylanor would have 8 class C ports, while Macene would have 7 class D ports.

At the 'outer limits', freight ports could exist for a pop 10, TL7 world, or a pop 2, TL F world.
 
You're right Kaladorn, traffic is an IMTU issue. In older models of Traveller, insterstellar space is much more frontiersy, and fleet sizes are rinky dink in comparison to the Grand Imperium TU.

<done-to-death>
I know it's not directly a measure of trade activity in the Imperium, but in MT, the 'fleet' size is 1000 ships, which probably comprises only the large fighting ships and ignores the tankers. The number most likely ignores ships under 5000 dtons, and might ignore ships under 10,000 dtons (references?). Oh, I don't remember the numbers now.

Oh wait, there's a slapdash way of calculating average (and total) Imperial traffic using Wild Assumptions:

(1) The slightly-better-than average Imperial world has a pop of 7, a TL of 12, a class B starport, and is 2 parsecs from its major trading partner, which has similar attributes.

(2) Using my QuITS, their traffic indices are probably 3. Since they are 2 parsecs apart, their effective value is reduced to 2 each, yielding a traffic index of 2, which equates to about 1000 dtons of freight per week, and 250 passengers per week, each way. Simplistically, this might be valued (at transport value) to be MCr 2.5 per week, or appx MCr 125 per year.

Mind you, this is all very sloppy.

(3) There are about 10,000 worlds engaged in trade. If they all average out, then they bring in 25 trillion credits per week, which is a whopping 1.2 quadrillion credits per year. For a sector, the number is more like 1.1 billion credits per week, and 55 billion per year. For a perfectly average subsector, the number is MCr 62 per week, or a bit more than 3 billion per year.

If the 'effective' index is a 1 instead, the results scale down by an order of magnitude. However, it's unlikely that an 'average' subsector ships less than 3 billion credits' worth of goods per year. By the way, that's 25,000 dtons of freight per week, 1.2 million dtons per year, per subsector.

And this dovetails nicely with my assumptions about fleet sizes: to protect one's interests, a fleet should cost about what your worlds ship in one week. So the Imperium's fleet should cost about 25 trillion credits, which doens't sound too far off the official mark.
</done-to-death>
 
Ooops, I just realized a side-effect of the above assumptions goes the other way too: the original assumption was that a fleet's size matches a week's worth of freight in displacement tons. That implies that IMTU the Imperial fleet is 10 million dtons. Since MT says there are about 1000 ships, the average ship displacement is therefore 10,000 dtons.

That implies that IMTU the 'fleet count' includes vessels under 10,000 dtons, so for every Tigress there could be a Gazelle, or a dozen Sloans.

All this is still handwavy. It's an exercise I've used to come to grips with the massive TU, provide a sanity check when I'm working with large-scale stuff, and allow me to define my parameters when I want to scale things back.
 
Originally posted by thrash:
For what it's worth, I did a detailed analysis of conventional vs. LASH vs. farport operations under GURPS rules for GT: Far Trader.
Perhaps you could convince Mr. Jackson to print some more of this very difficult to obtain supplement? I've been trying for weeks culminating in Marc M. selling me one on eBay then misplacing it. So quoting what is nearly impossible to get access to is merely frustrating... <sigh>

The question boils down to time versus money: can you save enough time (i.e., make enough additional trips per year) to pay for the extra infrastructure you'd need -- smallcraft drives and crews for LASH, space stations for farports -- to make an unconventional scheme work?
And in fairness, you have to not only include operating costs, but annual maintenance costs and the costs of the facilities to provide such maintenance.

It turned out that LASH was competitive with conventional operations: sometimes better, sometimes worse, depending primarily on the specifics of the system and the volume of trade. There is a discussion in Far Trader of how LASH operations work, and designs for a 10,000-dton LASH freighter and lighters.
Which will all be GURPS-y. I'm looking for MT/HG2 compatible designs. And ones I can actually access! (unlike GT:FT)

Also there are some underlying assumptions about trade which obviously GT:FT makes in order to assess the economic viability of these operations. These will do a lot to shape a TU.

Farports, however, -- though they had some very vocal fans -- could never be made to pay for themselves. In order to save enough time to make them worthwhile, you had to have so many (around a dozen, if I recall correctly) that they cost too much; most farports would be idle part of the time as orbital relationships change, or would need expensive (because of their size) maneuver drives for station-keeping.
We have this thing we call an orbit.... ;)

It only requires very low intensity drives, far short of 1G manouver. I don't think that'd be terribly expensive. You could even use some sort of a tug or tender to make nav adjustments, thus removing the need for the drive as part of the station itself. Such adjustments would rarely need made and thus one such tug or tender could possibly serve the entire system.

Plus, if they are automated using bots, your life support requirements are low, as are your salary requirements, and unused times result in a power down.

Remember also that most traffic in most systems is transient: it arrives at one point on the 100D sphere, and departs a different way pretty much at random (in the general case).
Hmmm. I can see arguments for and against such an assumption.

If you have to cross the intervening space anyway, a single, centrally located highport near the mainworld is a better investment.
That depends I guess on your costs. You have the ship's time from arrival to departure including inbound transit, outbound transit, offloading, and onloading. In that time, you pay all fees for dockage, all fuel and salary and life support expenses. In the farport case, you spend less time in system. Whether this makes it economical depends a lot on how much those expenses are really costing you.

Farports make sense where you have only a few major trading partners, and you can predict that most of your interstellar traffic will be on shuttle runs, returning to its point of origin.
I imagine that trade between high pop worlds may well fill this kind of a model. JIT delivery just isn't a factor in OTU commerce between stars (it can't be, given the 2+ week delay in orders being serviced). So things will tend to run on schedules (plus there are Vilani involved). And much trade will be of a predictable nature with much bulk transport, especially between worlds with key and related needs/capacities to produce.

This would make farports more viable, but I imagine most sectors have several places where this kind of relationship makes sense.

Other rules sets with different assumptions and cost factors (using reaction thrusters, say, or without GT's jump masking) may result in different conclusions, of course.
The point you make is fairly taken - a lot depends on your assumptions, your version of the ship construction rules, your costs for fuel and berthage, your amount of fuel burned, your salary schedule, etc. etc. etc.
 
As a similarly unrelated aside, I find it interesting that trade never seems to make reference to specifics of a world such as temperature, atmospheric pressure, etc (all of which might combine to be a habitability index). Nor does the population rating seem to be affected by this. Thus the Imperium, using expanded system generation, seems to be full of lowly populated and trade limited worlds which are lovely places with nice temp and pressure ranges next door to high pop places which have huge trade but are actually terrible places to live (poor temp and pressure for habitability).

Now, one can justify this one time, ten times, even a hundred. But on the scale of the OTU, many of these places would be migrated to, due to their attractiveness and similarity to human biosphere norms.

And trade might be coloured by a lot of the attitudes that WBH generated, by religion, by law levels and government types.... but in more sophisticated ways than the simple trade classifications allow for.

Still I guess the existing classifications are better than nothing and I don't (at present) have a better suggestion.
 
Originally posted by thrash:
To clarify: There are two options. (1) You can allow your farports to orbit, and they will periodically go out of position to serve any likely entry/exit vectors -- how often and for how long, we can't know (see below).
That makes a few underlying assumptions in and of itself.

No doubt. The problem is that there isn't any better assumption available, given that we don't know how three-dimensional star systems relate to one another across the two-dimensional star map. With an average of 30 worlds within Jump-4 even on the flat map, random orientation is as good as it gets in the general case.
Hmmm. We don't know that passages between two particular places don't generate a common arrival locus that is in fact a restricted area of space. I will concede that we don't know this either, so you are correct in that we don't have any reason to assume the situation is *better* than random, but it may be so.... or it may be so in some TUs.

Or were you objecting to the idea that most traffic is transient? That falls out when you realize that high population worlds trade largely with each other, that they are separated by multiple jumps (on average, 2-3), and that all other trade is carried on peripheral to this traffic (at least to first order).
I wasn't, but if I was to object to this, I'd have had to ask you to define transient as you mean it (to me, it means coming and going, which all ships would inherently be).

Trade (the arrival of ships) is, in some frames of reference, always doomed to being discrete. Depending on how you consider it though, some high trade pathways may in fact be closer to (in practical terms, avoiding semantics) continous.

Nope: if ships arrive and depart from different, randomly selected points on a sphere,
the most efficient place to put a port is in the center of the sphere -- shortest average travel time to/from all points. Since the center of the sphere is either the mainworld itself (for stars larger than ~G5V) or its primary, a highport in orbit around the mainworld is as centrally located as a port can be and still be above the atmosphere.

It's only when arrival and departure points are somewhat correlated that off-center ports become more efficient.
I think not. (I'm open to the possibility I'm wrong, but....)

I was dealing with the circular 2D case, but you can extend it to 3D (I leave that as an excercise for the citizen himself). If I station N stations at equal separation around my 100D orbit ring, then at most I have to travel (if I arrive halfway between any two) the length of the chord from my arrival point to the nearest transfer station. If that number is less than 100D (the gauranteed distance to the highport, though it could be as high as 100.5D and as little as 99.5D based on the side of the world the highport is on), then you recieve an efficiency.

In order to determine if this efficiency makes orbital sense, you need to know the cost of your N transfer stations (see my comment on automating them), their maintenance, and the saving for having a smaller highport as well as the cost of flying your ship in to the highport to unload and back out. You also need to know the number of ships in order to divide the cost of the transfer stations out across that number of ships to determine the fair portion for each costwise (or if you want to do it by ship cargo tonnage, that might be fair). Anyway, this is more than a simple problem and requires significant data.

But, with sufficient trade, sufficiently cheap transfer stations, a reduction in main highport size, and some reference to the size of the 100D limit and average freighter in-system travel rates (and hence costs), we'd be able to determine where this made sense, minimum values of N (numbers of transfer stations) and thereby the threshold where this type of operation makes sense. Extending it to 3D merely increments the value of N but the math is roughly the same, just the results differ.

Care to argue why this is not so?

Have you seen my proposed alternate for Book 3 world generation?
No, but I've bookmarked it! It should be HTML'd and put somewhere 'entire'. Nice, though it still doesn't factor in population clustering - that is to say that part of apparent habitability will be dependent on the relationship between worlds nearby and the world being created. Also, populations may be affected by the ease of availability of nearby support/markets/etc.

But I'm not asking you to factor that in (unless you're bored? *grin*)

;)
 
Originally posted by thrash:

Interestingly, I get 5 million dtons per fleet as an average, with a range of 2-12 million dtons. This neglects escorts and small auxiliaries (which appear to total less than 10% of combined capital ship displacement), but does include tanker and assault squadrons (per Fifth Frontier War). I've always inferred that MT's "1,000 ships per fleet" includes all jump-capable vessels, however.
OT, but I couldn't resist:

That "1000 ships" comes from MT's Rebellion Sourcebook, and it explcitly says it doesn't include all ships: "Each sector of the Imperium theoretically has a group of fleets numbering about 1000 ships. This number includes combat vessels such as cruisers, carriers, battleships, and some escorts; it does not include auxiliaries, support ships, and scouts."

I've always assumed the "and some escorts" to mean that secorts in combat 'Rons would be counted, while those in rear area 'Rons (such as those escorting supply ships) weren't - it seems the easiest divsion.
 
thrash wrote:

"Marc Miller has said that exit points can be calculated to within +/- 125,000 km (+/- 25,000 km for naval maneuvers)."


Mr. Thrash,

Where is that bit from? The only physical accuracy number I know of is the 3000km/parsec jumped parameter from MWM's JTAS jump space essay.

Is it from T5?


Sincerely,
Larsen
 
Originally posted by thrash:
Sure: you're not taking the departure into account.

There's nothing to guarantee that the point from which you need to depart for your next destination isn't a quarter of the sphere away from that nearest station -- at least half the time, it will be. You'd then have to travel a distance at least equal to the sphere's radius to clear it, plus the chord you originally travelled inbound. Your time savings over simply driving to the center and out again have just become considerably more marginal. Now throw in the fact that you may sometimes have to clear the primary's jump limit as well (much more frequently if you assume jump masking, but it occurs even if you don't) and there's too little advantage left to pay the rent.
1. I was not aware of any canon (pardon me if I don't count GT here) that indicated departure was from a specific point outside of 100D. That is to say, in my model, anyplace you can get outside of 100D, you can jump from. If this is not so, I'd love a citation. If you are only assuming that is the case, then I question that assumption. I always assumed (since you don't calculate your jump until the last minute) that you could jump from any place. If the departure point is not restricted in locus, this restriction goes away. If it *is* restricted in locus, then you have a point. But where does this become explicitly stated?

2. In the case where locus is explicit, the average case will place my departure 1/2 way around the sphere from the station I'm at (90 degrees off). This means I have to travel that chord, plus the chord I had to enter with. Whereas the inbound ship had to travel 200 diameters! I have to travel a distance that would be (root of(100D squared plus 100D squared)) on that cord (141D or thereabouts IIDMMR). But this makes the assumption you are making about a fixed locus of departure points.

If departure points are fixed and arrival points are two, I might try your 'station keeping' stations.

True enough -- but it was designed to be as simple to use as Book 3: roll some dice, write down the results, and move on to the next system. What you're describing would require multiple passes and probably a spreadsheet.
Or a program.


I've worked on and off on these things with someone who is among the world's top population modellers. Scary stuff, sometimes. But it makes interesting thinking to try to simulate and track not only population growth but all the various causes of migration in and out, mortality, natality, and to track by age cohort and how this affects birth rates, etc. and how wars and disease and such play into it.

I just dream big ;)

If you assume that the populations in the Imperium have reached saturation -- and they should, after between one and ten millenia -- then distribution will mostly follow affinity (MSPR+RAM, in my model) anyway, with some variation at the low end for stations on trade routes and such. The full article goes into this in more detail.
Presuming no massive dislocations or reductions in population or other phenomena which make population settling fall outside that model, yes.

If I had the spare cash, I join JTAS. Not for this moment however.
 
Ok, let me just say that I love this whole idea. Every bit of it makes perfect sense. Except for one thing: Jump-capable cargo containers?

It doesn't make any sense to put the fuel/jump drive on the cargo containers. These are standardized, used everywhere in the Imperium, whether it be behind a truck or a spacefaring tractor, right? If you're hauling a container around on a truck, does it make sense to fill up 20% of it with jump equipment? That you'll never use when it's on the ground?

Do modern-day tractor-trailers put the engine in the tractor or the trailer? The tractor. Why? Because that way you get the most efficiency out of the container. If the container is used for more than just spacefaring transport, then it makes no sense to put anything other than cargo in it.

I would suggest that this sort of setup would involve several standardized sizes of containers, and like someone mentioned earlier they're all stackable. Furthermore, some have special equipment for hauling certain cargo, such as refrigerated, radioactive, living, or any other strange cargo you'd roll up.

This setup is remarkably like todays shipping industry, where there are several different sizes of container, along with different types such as refrigerated and such, but they all fit together.

Transporting these containers falls to large 'semi-tractor' ships, equipped with powerful jump drives and lots of fuel. And that's about it, they're made to haul LOTS of cargo.

Allowing for different models of tractor, the largest hauler would be able to do J-1 with 6 containers, J-2 with less. Smaller tractors would obviously haul less, and would most likely be seen around less populated regions.
 
I wrote to Mr. Miller for his ruling, and this was his response:
I'll never know what he said, because for some reason I find myself hammering my head against the screen, ripping out my eyeballs, and screaming "la la la I'm not listening!"

I didn't miss anything important, did I, like a total ⌧ing up of the entire OTU?
 
Originally posted by Jered Farstrider:
Ok, let me just say that I love this whole idea. Every bit of it makes perfect sense. Except for one thing: Jump-capable cargo containers?
Well, my lighters certainly weren't jump capable!

It doesn't make any sense to put the fuel/jump drive on the cargo containers. These are standardized, used everywhere in the Imperium, whether it be behind a truck or a spacefaring tractor, right? If you're hauling a container around on a truck, does it make sense to fill up 20% of it with jump equipment? That you'll never use when it's on the ground?
Nope.

Do modern-day tractor-trailers put the engine in the tractor or the trailer? The tractor. Why? Because that way you get the most efficiency out of the container. If the container is used for more than just spacefaring transport, then it makes no sense to put anything other than cargo in it.
LASH ops use lighters loaded with standardized tractor-flatbed compatible containers. In the TU I'm conjecturally thinking about, this means the lighters 25 tons of cargo space (30 dTon lighter) is likely packed with 3 8 dTon tractor-trailer containers.

I would suggest that this sort of setup would involve several standardized sizes of containers, and like someone mentioned earlier they're all stackable. Furthermore, some have special equipment for hauling certain cargo, such as refrigerated, radioactive, living, or any other strange cargo you'd roll up.
Plus some pretty fancy methods of securing the containers and cargo, which might include features built into the containers themselves.

This setup is remarkably like todays shipping industry, where there are several different sizes of container, along with different types such as refrigerated and such, but they all fit together.
Obviously the inspiration came from somewhere!

Transporting these containers falls to large 'semi-tractor' ships, equipped with powerful jump drives and lots of fuel. And that's about it, they're made to haul LOTS of cargo.
Or more correctly, there are a variety of ships of this type of different sizes, the larger being more efficient (the difference between a train and a tractor trailer - train has efficiency, but doesn't operate everywhere... the tractor goes into out of the way places....).

Allowing for different models of tractor, the largest hauler would be able to do J-1 with 6 containers, J-2 with less. Smaller tractors would obviously haul less, and would most likely be seen around less populated regions.
Yep.

Seems to me like you've hit on the head exactly what I was thinking of.
 
I actually had already read your questions and replies (they exist on the Net somewhere, along with a disturbing treatise by Marc on the fact that all J-drives burn maximum fuel regardless of jump length, thus a J-3 drive burns a J-3 amount of fuel even doing a J-1....).

Re Masking:

Yes, I'm aware this can happen. It seems to me 100D of many stars is beyond the habitable zone, so many systems have a *far greater* issue than the 100D limit of planets. Ignoring this bugaboo....

Your point about passenger and freight transfer outbound are well taken.

Although:

1. A well travelled trade route, having frequent journeys sys A to sys B, would in fact be able to dump a passenger out at any farport with a high probability of them getting outbound fairly expediently. This does require an active shipping schedule, I concede.
2. The costs all have to be figured in, but if the cost of in-systems shuttles and the farport stations (as many as them as you need to create an efficiency sufficient to make their presence wrothwhile) is cheap enough, it may be possible to create a viable system. I'll review your math and try some of my own - although I expect any useful simulation or analysis to take some notable amount of time and have to be very careful in listing its assumptions and the effects of relaxing those assumptions.

BTW, I may be putting up a bit of an argument (discussion) but I appreciate your work and really am miffed that I'm having no luck getting a hold of GT:FT.... it seems to have (by all accounts) a lot of good thinking put into it.
 
I have a question about these, actually.

Seems to me it's been decided that there are the heavy haulers that run on high-traffic mains, able to haul up to 6 containers at J-1. And there are the midsize ones, able to carry maybe 3 at J-1. And obviously the little independent, who carries just one container. And a good variation on these as well.

My question is: What is the effect of reducing the number of containers? For example, take the heaviest big rig, and instead of loading it to full capacity of 6 containers, you only load 3. Would this allow it to reach J-2, due to being so unloaded? Or would it mean that you can travel J-2 routes, but at 1 parsec per jump, refueling halfway between systems? Or would it do something else entirely?

P.S. I'm new to Traveller, if you didn't know, and I haven't the slightest where to look this up. Thanks.
 
Jered, the answer to your question depends on a number of things.

Depending on the container ship (or LASH, if it loads lighters) design, reducing the pod count to a particular level will let it attain increased jump capabilities (I think) due to having enough jump engine for its size. However, I'm not positive of this, because it may be that different jump ratings actually involve slightly different components, etc, so it may not be the case.

One way or another, it is not as simple as halving the cargo.

What we have here is cargo + ship = x dTons (fully loaded) where x is the ship's full displacement. We have to halve x to get (if the logic follows) a doubled jump number. OTOH, halving the cargo won't be enough, unless the displacement of the ship part is zero. So, we need to reduce the cargo load by half of x, whatever x is, where x is the sum total of a full cargo load's displacement and the ship's own displacement.

Let us say we have a 60 ton spine and 240 tons of cargo pods in 6 40 ton pods (totally made up numbers here....). So, total dtonnage is 300. To reduce to 150, we have to drop 150 tons worth of cargo, or 4 40 ton pods (for 160 tons). This only leaves 2 pods. (See what I'm getting at?)

Overall observation, not related to this point:

As you reduce the pod count on a design, you probably slighltly reduce commercial efficiency. So a route that will support a 40 pod spineship is going to get the best economy out of a 40 pod spineship rather than 8 5 pod ones. (Just due to the details in ship construction...).

Observation (thought point) related to pods and jumping:

It occurs to me that you would have to (if you believe SOM) have a lanthanum grid in each of the pods or lighters hulls. Now, if we argue this is a near zero-mass component of jump drive, we can probably argue for it as 'an invisible inclusion'. If, however, we believe that it isn't (along with the shunt circuits) a zero mass inclusion, each capsule would have to have at least *some* component of the jump drive. I say this based on the assumption that, in order to correctly form the jump space bubble that you need around your ship to prevent it from interacting with jump space catastrophically, you need all of the hull area generating the field. This may not be so.

Thoughts?
 
Thought:
Fairings around lighters and pods protect them from various space hazards. The Fairings are retracted or otherwise moved when the pods etc are needed.
 
Originally posted by Hecateus:
Thought:
Fairings around lighters and pods protect them from various space hazards. The Fairings are retracted or otherwise moved when the pods etc are needed.
That's kind of like my thoughts on how drop tanks need to be rationalized to work for MTU.

For example the 300T Gazelle class Close Escort has to be built as a 400T hull. This gives you the 4 hardpoints it is allowed and includes the fairings and clamps and fittings to allow it to handle the 100T of drop tanks. When the tanks are dropped it all folds down along the sides of the core 300T hull and you're good to go.

This allows the drop tanks to be made cheaply (cr1,000 per T), far cheaper than standard hull costs, while still gaining the benefit of armor and jump capability. The extra cr10,000 required for drop tanks covers the cost of the installation, and IMTU (for drop tanks at least and possibly cargo modules too now that I'm thinking of it) needs to be paid each time, even if the drop tanks themselves are recovered.

The only other fair and reasonable way to handle it (from the CT/T20 rules at least) is to make them externally docked hulls and pay for full hulls and the mount with all it's extra required volume. I know which system I'd chose as a player
file_22.gif
and I'll probably go with it as GM too.
 
A reasonable solution, but in this case it suggests that our lash spineship actually is built with a 300 ton hull (rather than a 60 ton hull) to accomodate the 240 conjectural tons of podage. Could certainly be done that way, though it makes the ship a wee bit heavier/more costly. This implies the lighters/containers are actually stored inboard, but this maps to actual LASH ops, so I have no issue with that and it neatly solves the issues.

However, I'm not sure the 10K bucks you want to pay for mating makes sense. You'd think by this period, you could design in magclamps and a mate-up datalink capability (in the case of cargo pods, in the case of fuel pods, this would include feed hoses) and that an engineer could do this himself or with a little help, without spending 10 KCr. Now, if you want 'explosive jetison', then maybe you have an installation issue (setting, installing, and arming new charges). Otherwise, with a simple mag clamp, this should mate-in just like cargo containers or lighters would.
 
Originally posted by kaladorn:

It occurs to me that you would have to (if you believe SOM) have a lanthanum grid in each of the pods or lighters hulls. [...]

Thoughts?
That could be handwaved away by building a ship that's just a big hangar with a jump drive, as if it were a Tender of some sort.

But that made me think about the Fourth Imperium... imagine the boon to interstellar shipping when the Type 1 (inanimate materials only) Jump Gates are built... cargo containers are simply ferried to a gate and pushed through them.

Simply wonderful.
 
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