CT Only: Spinward Flex Courier

[Silverhawk]

As much as the market will bear.

Adjusted by government taxes or subsidies, though it could be it's in the interest of the Imperium to keep it stabilized at a hundred starbux per tonne for unprocessed, and five hundred for processed.

Actual starting point being cost of production.

I would say that it is very likely in the interest of the Imperium to keep the price of fuel stable. I would also expect that a company that sets itself up to supply that fuel would make sure to take advantage of any by products of processing that can be sold to add to the bottom line.

 

[Spinward Flow]

I would say that it is very likely in the interest of the Imperium to keep the price of fuel stable.

Agreed.
Keeping fuel prices "fixed" at the same price point for both buyers and sellers eliminates market volatility and opportunities for price gouging (on either side of the ledger).

I would also expect that a company that sets itself up to supply that fuel would make sure to take advantage of any by products of processing that can be sold to add to the bottom line.

Also agreed.
One man's trash is another man's treasure (and all that). Just because unrefined fuel is "contaminated" with elements other than hydrogen doesn't mean that those "contaminants" are themselves worthless. They may be worthless for the purposes of starship fuel, while simultaneously being valuable for chemical industry processes and the like, which wind up getting collected in the fuel purification plant's "filters" and "waste" storage systems (assuming those elements aren't vented overboard) which then get recovered during annual overhaul maintenance. The quantities are too small for a single starship to see a return on, but a type A or B starport doing a significant number of annual overhauls can collect enough "waste byproducts" of the fuel purification processes to generate a supporting revenue stream from fuel purification as a feedstock for local chemical industries.

It's a lemons vs lemonade kind of situation.

 

[Condottiere]

Unless the planetary government is weak, I doubt it would permit sipping from it's hydrogen sources, so most likely it's a processing plant in the nearest gas giant's orbit, plus tanker(s).

If it's strong, it may issue permits to harvest from the gas giant.

 

[Spinward Flow]

So I'm a little late in posting this and for that I'm sorry. I was thinking about the collect a load of fuel to process and sell on arrival since there is time. I'm not saying that you can't after all its your TU. But why wouldn't a company work a contract to handle bulk transport of fuel. I started noodling around with a 400,000 dTn design that would allow you at TL13 to handle roughly 250,000 tons. On board processing and you can depending on the impurities work some profit in selling those for industrial use. Jupiter for example has helium and methane in its atmosphere.

Of course, that got me thinking about crew sizes only because at this point it is something on the or of 500 to 600 to run the thing. Mostly engineers for the drive room.

Just a thought.

So here's a challenge for you that you (and others) might be interested in taking up.

Design a "local" fuel tanker non-starship or small craft with a fuel purification plant (which kind of requires LBB5.80) that minimizes overhead costs (life support, crew salaries, berthing fees, annual maintenance costs) while maximizing revenue generation (Cr 500 per ton of refined fuel delivered) as an in-system fuel tanker design at TL=9 (for widest possible manufacture and support at type A and B starports) as a common use non-starship design.

There are two economic criteria that a "local" fuel tanker design must achieve ... profit margin per delivery (absolute value of revenue minus costs generated) and profit margin over time (rate value of revenue minus costs generated on a per day/hour basis).

From a design standpoint, this basically comes down to a matter of finding "a sweet spot" compromise of a number of competing factors (welcome to engineering!) where a ship design is getting "the most" out of its expenses (crew, life support, etc.) while simultaneously generating the highest amount of revenue possible. Depending on a variety of factors, you can have a situation where "bigger isn't always better" for a variety of reasons, simply due to scaling factors (such as needing 500-600 engineers for a tanker). When you're optimizing for Rate Of Return On Investment, there will often times wind up being "islands of stability" along the continuum of possibilities that wind up yielding a greater rate of return than other confluences of factors.

For example ... a fuel purification plant has a minimum size (1/5th of 1000 ton capacity) ... so any fuel tankage that winds up being 200 tons or less is "wasting" some amount of fuel purification capacity, therefore the minimum "most profitable" fuel purifying tanker is going to need at least 200 tons of fuel capacity.
Likewise, crew requirements that yield a "round up fraction" of crew numbers required is also "wasting" some of its manpower capacity (6 crew needed to do the work of 5.4 required, for example).

900,000,000km (Far Gas Giant distance) of transit distance travel times do not scale linearly with maneuver drive power increases.
1G = 168h (7 days)
2G = 120h (5 days)
3G = 108h (4.5 days)
4G = 84h (3.5 days)
5G = 84h (3.5 days)
6G = 72h (3.0 days)

600,000,000km (Near Gas Giant distance) of transit distance travel times do not scale linearly with maneuver drive power increases.
1G = 144h (6 days)
2G = 108h (4.5 days)
3G = 84h (3.5 days)
4G = 72h (3.0 days)
5G = 72h (3.0 days)
6G = 60h (2.5 days)

Given that a 2G maneuver drive doesn't "cost" that much more additional tonnage and crew to maintain, there may be a "sweet spot" in the design and operational criteria where a slightly more expensive to build and operate 2G fuel tanker is capable of generating more profit over time than a 1G maneuver drive version can, simply due to the increase in cycle tempo times generating more revenue value faster (running outbound plus inbound through the star system).

5 complete fuel transit cycles @ 1G in 70 days ... versus 7 complete fuel transit cycles @ 2G in 70 days ... to a Far Gas Giant (900,000,000km).
3 complete fuel transit cycles @ 1G in 36 days ... versus 4 complete fuel transit cycles @ 2G in 36 days ... to a Near Gas Giant (600,000,000km).

Think about it.
If you were a merchant line contracted to supply such an operation ... what kind of a non-starship or small craft would you order up for your operations?

 

[Spinward Flow]

Unless the planetary government is weak, I doubt it would permit sipping from it's hydrogen sources, so most likely it's a processing plant in the nearest gas giant's orbit, plus tanker(s).

If it's strong, it may issue permits to harvest from the gas giant.

Does government code: 1 count as "weak" in this instance?
How about law level: 0 ... does that count as "weak" too?

D'Ganzio^X / Lanth / Spinward Marches ... B420410-D N Desert. Non-industrial. Poor. G

Also, good point that it's perfectly possible to build an orbital fuel refinery station around a gas giant (or two) with "local" tankers simply hauling unrefined fuel to the refinery in orbit (short trip) and then having other tankers (although possibly the exact same tanker design) hauling refined fuel to a different stellar orbit in system (the mainworld) to supply the starport.

However, depending on the model of operations (single staging versus double staging through an orbital refinery) and the specifics involved (highly efficient use of refining capacity and crew balance per tanker) the orbital refinery option might wind up being more of a liability than a savings in the grand scheme of things. It all depends on how you build it (welcome to engineering!).

So while the answer to the question may LOOK obvious, the actual "optimal" solution may not always be the first one you think of.

For one thing, if you build a massive fuel refinery in orbit around a gas giant ... that asset is going to need to be protected (orbital debris damage, sabotage attempts, maintenance/repairs/inspections, etc.) in ways that make a centralized capital investment like that less attractive than a more dispersed option of simply putting fuel purification plants on the individual fuel tankers making the fuel runs, which winds up being less of a risk because the costs of those risks are more widely distributed (and harder for an adversary to leverage against a business interest).

Isn't economic warfare among merchant lines fun to think about?

 

[Condottiere]

Rather the orbital processing plant, than the dirtside Starbux.

 

[Fovean]

For one thing, if you build a massive fuel refinery in orbit around a gas giant ... that asset is going to need to be protected (orbital debris damage, sabotage attempts, maintenance/repairs/inspections, etc.) in ways that make a centralized capital investment like that less attractive than a more dispersed option of simply putting fuel purification plants on the individual fuel tankers making the fuel runs, which winds up being less of a risk because the costs of those risks are more widely distributed (and harder for an adversary to leverage against a business interest).

It’s a fun idea, working out a decent system-wide fuel shuttle. But you’ve touched on why I don’t care for onboard fuel refineries.

They make things too easy.

Once they exist there’s no reason for the Cr100 vs Cr500 fuel costs. There’s no reason every ship won’t have them and allocating a handful of dtons and a few MCr is just stingy, they would be as ubiquitous as grav plates and subsumed into Hull cost. No reason for fuel-based jump DMs. Just add x hours to the travel times and subsume a skimming trip into part of the “100 diameter experience.” And tip well on the worlds where you can skim the oceans.

If they really are so small and efficient they should push a lot of the economic game into the background.

 

[Spinward Flow]

It’s a fun idea, working out a decent system-wide fuel shuttle. But you’ve touched on why I don’t care for onboard fuel refineries.
They make things too easy.

I'm not disputing that point. They DO make things so much easier for starship logistics (as demonstrated in this thread).
But then, so do so many technologies.
Imagine trying to do all the things we do today ON PAPER rather than in computers. There are so many things we take for granted in 2021 that 2 to 3 generations ago were the subject of science fiction. I mean, we're living in the Star Trek age now ... where we have touchscreen computing ... and a Starbase for reusable spacecraft!

Once they exist there’s no reason for the Cr100 vs Cr500 fuel costs.

There is ... but it's more of a butress to the spacefaring economy than a foundational pillar at that point.
It's also still relevant for locations where there is no easily accessible wilderness refueling option ... such as Frenzie/Vilis, or Arba/Lunion or even Gitosy/Rhylanor in the Spinward Marches (to name a few quick examples), where feedstocks for starship fuels would need to be MINED rather than scooped via simple wilderness refueling options, in which case starports (and spaceports) would have a near monopoly on distribution from their respective fuel supply chains.

There’s no reason every ship won’t have them and allocating a handful of dtons and a few MCr is just stingy

Well, as I've already demonstrated in this thread, you COULD install a TL=9 fuel purification plant onto a Free Trader or a Far Trader (at the expense of some cargo capacity) to enable wilderness refueling operations that yield refined rather than unrefined fuel as an aftermarket modification (akin to installing turrets and weapons, for example). And thanks to the contents of this thread, I think I can say I've made a conclusive case for WHY a merchant line would want to do that rather than keep the higher cargo capacity available for speculative cargoes (the REAL moneymaker!).

they would be as ubiquitous as grav plates and subsumed into Hull cost. No reason for fuel-based jump DMs. Just add x hours to the travel times and subsume a skimming trip into part of the “100 diameter experience.” And tip well on the worlds where you can skim the oceans.

Well ... maybe.
Fuel purification plants are only of use in places where wilderness refueling is an option (worlds with liquid water oceans, gas giants, etc.).

In other words, just because fuel purification plants are "useful" in a LOT of places, doesn't ipso facto mean they're usable EVERYWHERE without limits or restrictions.

If they really are so small and efficient they should push a lot of the economic game into the background.

Depends on how ... invested ... a Referee is about getting into the economic game background I guess.

 

[whartung]

So here's a challenge for you that you (and others) might be interested in taking up.

I actually did this using FF&S (but can't seem to find the post, can't seem to find a lot of posts...).

It involved an outside a facility outside of 100D in solar orbit, perhaps stabilized and maintained to "keep up" with the primary world. The fundamental premise was a shipping hub. Large ships would enter and dock with this facility, and cargo would transfer to and from it for local delivery and interstellar destinations.

Part and parcel to it was an infrastructure of fuel shuttles and fuel pods. The shuttles would fill the pods with unrefined fuel at the gas giant, and then push them inward toward the facility. There would be a train of "dumb" fuel pods constantly in flight, recovered and maneuvered by fuel shuttles, drained in to a processing facility, then shoved back. I priced out rough numbers for the ships and the pods and the crews and what not, including redundancy (you really don't want to be missing the pods flying in, and chasing them, so best to have enough ships on hand to catch them).

The only thing I didn't really consider was when the gas giant was on the wrong side of the primary. In that case you may need a relay operation to catch the pods and redirect them to the facility (and vice a versa) to route them around the star.

If you had a large enough volume to justify the infrastructure in ships and pods and labor, at the classic "100cr/ton vs 500cr/ton" prices of unrefined and refined fuel, it easily paid for itself. That 500% markup has real impact.

 

[Spinward Flow]

In that case you may need a relay operation to catch the pods and redirect them to the facility (and vice a versa) to route them around the star.

Inertial only orbits tend to be elliptical/circular, not straight lines, by default. The star being in the middle wouldn't be a problem.

 

[whartung]

Inertial only orbits tend to be elliptical/circular, not straight lines, by default. The star being in the middle wouldn't be a problem.

They become elliptical, of course. It's just a matter of how elliptical. The problem with the start is getting "the turn" right, and I simply don't know if there's a "perfect" orbit that can direct the payload properly to bend around the star (or any gravity well of note) correctly to get within the capture window of the receiving facility.

The beauty of Traveller is that we have the power to "turn and burn" rather than being at the mercy of gravity the system has given us. Consider the trajectory of the Rosetta spacecraft to come in to the contact with the comet. It made several loops through the inner solar system before finally meeting up. We don't have to do that in Traveller, we get to point and shoot.

So, maybe theres a trajectory to get the payloads around the star, and in those cases, the astrodynamics plotters can set it all up, but if it doesn't quite work, they can dispatch relay shuttles to simplify and speed up the process.

 

[Condottiere]

Time is money; I can design pretty cheap low performance spacecraft, but that might not necessarily be the most economic solution in every circumstance.

 

[Spinward Flow]

To be honest, if all you're doing is "chunking pumpkins" around on inertial navigation orbits, you only need a mass driver (read: Launch Tube out of LBB5) to launch the discrete unmanned fuel tanker modules on a "near miss" orbital trajectory near the destination. At the destination, you then have 6G maneuver tugs race out, latch on and "reel in" the unmanned fuel modules that are orbiting purely on inertial momentum imparted to them from the launcher all the way out at the refinery. That way, you get an enormous fuel fraction to the displacement of drive tonnage involved and the "main" expense is for the multiple hulls (configuration: 4) of a standardized size that are cheap and easy to make. The "limit" on the efficiency of the system then gets determined by the size of the launch tube needed to "throw" the fuel canister modules around the solar system for the long interplanetary trips ... and you just need a fleet of maneuver tugs to "marshal" their movements between skimming and orbital refinery on one end and also the "capture field" and destination (like a starport or spaceport) on the other end. Keep the fuel canister sizes small enough that the loss of one (or a few) isn't going to have a huge impact on the economics and you can essentially set up what amounts to a remarkably substantial partial "bucket brigade" of routine launches on orbital paths through a defined "capture field" volume using tugs to rendezvous with the fuel canisters near when they need to be delivered to.

Sort of a "catch and release" kind of business model.

 

[Spinward Flow]

Time is money; I can design pretty cheap low performance spacecraft, but that might not necessarily be the most economic solution in every circumstance.

Exactly.
Sometimes cheaper on the front end is more expensive in life cycle costs ... as I've been at pains to demonstrate during the Race To Profitability ... but that depends on situations and circumstances. It's why I say that 1G maneuver drives are cheap to buy but expensive to own, which sounds nonsensical ... until you start seeing the full scope of risks and missed opportunities that skimping on maneuver drive performance can yield for you.

The same principle applies elsewhere when it comes to engineering space craft (interplanetary and/or interstellar) optimized around specific use cases, or generalized for a variety of use cases when you never know what services you might wind up being called upon (and paid) to provide.

 

[whartung]

Sort of a "catch and release" kind of business model.

Yea, exactly. In my write up, I had 5K ton modules being flung.

 

[Silverhawk]

The only thing I didn't really consider was when the gas giant was on the wrong side of the primary. In that case you may need a relay operation to catch the pods and redirect them to the facility (and vice a versa) to route them around the star.

Which is probably why when I started thinking about this while walking my dog that I decided on a ship that served as tanker and purification paint. Has a certain manpower intensity but turns 'Where in the system is the Gas Giant?" into a non factor.

 

[Spinward Flow]

I decided on a ship that served as tanker and purification paint. Has a certain manpower intensity but turns 'Where in the system is the Gas Giant?" into a non factor.

Actually, now that I think about the matter even more (you see what you people do to me?), there are 2.5 ways to cut down on manpower (and thus, life support) required per ton of fuel shipped ... keep the tankers under 200 tons (no need for engineers or medics aboard) ... or just go really big for economies of scale (which then creates massive drives that need lots of engineers for internal fuel tankage) ... or do a mix of both by using a tug+barge business model that basically amounts to small boat with small crew with powerful maneuver drives acting as a maneuver tug for a really large (unmanned) detachable cargo pod that is simply ALL fuel.

And even better yet, the 5G TL=11 Spinward X-Courier and also the 6G TL=13 Spinward Flex Courier are BOTH capable of yielding the necessary performance to make this happen (albeit with some unnecessary systems above and beyond the needs of a "pure" fuel tanker barge/tug arrangement). The important point I'm wanting to make here is that either starship COULD be pressed into this kind of fuel tanker service if necessary.

Observe.

Spinward Flex Courier  XF-1626621-030000-00002-0   MCr 109.8752  194 tons
    batt bearing                   1         1                     TL=13.
    batteries                      1         1                    Crew=2.
Passengers=0 (1 possible). Cargo=45. Fuel=50.5. EP=11.64. Agility=6. FPP.
Jump-1, Maneuver-5 with 0.1-41.5 tons external cargo added.
Jump-1, Maneuver-4 with 41.6-97 tons external cargo added.
Jump-0, Maneuver-4 with 97.1-105.8 tons external cargo added.
Jump-0, Maneuver-3 with 105.9-218.2 tons external cargo added.
Jump-0, Maneuver-2 with 218.3-465.6 tons external cargo added.
Jump-0, Maneuver-1 with 465.7-1455 tons external cargo added.

Interplanetary Travel (distance, acceleration, time) (link)

Spinward X-Courier   XF-1626621-030000-00001-0   MCr 121.5184  194 tons
    batt bearing                   1         1                   TL=11.
    batteries                      1         1                  Crew=2.
Passengers=0 (1 possible). Cargo=45. Fuel=48.5. EP=9.7. Agility=5. FPP.
Jump-1, Maneuver-4 with 0.1-52.9 tons external cargo added.
Jump-1, Maneuver-3 with 53-97 tons external cargo added.
Jump-0, Maneuver-3 with 97.1-145.5 tons external cargo added.
Jump-0, Maneuver-2 with 145.6-349.2 tons external cargo added.
Jump-0, Maneuver-1 with 349.3-1164 tons external cargo added.

Interplanetary Travel (distance, acceleration, time) (link)

What this means is that if either starship is equipped with a 1000 ton L-Hyd drop tank (MCr 1.01 @ Cr 1000 per ton plus Cr 10,000) to be "towed" externally ... both would be capable of towing the L-Hyd drop tanks at 1G.

900,000,000km (Far Gas Giant distance) @ 1G = 168h (7 days)
600,000,000km (Near Gas Giant distance) @ 1G = 144h (6 days)

So if hauling/transporting 1000 ton L-Hyd drop tanks (MCr 1.01 for each drop tank) purely as "reusable" fuel tank storage in normal space (so not using them to make jumps), the fuel purification plant onboard each starship would be rated to purify up to 200 tons at a time and would then just simply use the "long slow barge trip" to perform any fuel purification slowly while en route in between planets, during which there are plenty of hours/days to get the job done over time.

For a system like Regina/Regina or Choleosti/Vilis (for example), where the mainworld is a moon of the gas giant, the fuel purification step could be skipped so as to simply deliver more loads of unrefined fuel at a higher tempo (presumably more than 5x faster to offset the price differential between refined and unrefined fuel deliveries) and then just let the starport refinery deal with the process of refining fuel scooped from the gas giant.

Revenue generation per round trip (12-14 days depending on the near/far distance to the gas giant) would be on the order of:

• Cr 100,000 per 1000 tons of unrefined fuel
• Cr 500,000 per 1000 tons of refined fuel

... assuming a 1:1 ratio of buy/sell pricing through the starport.
Charter basis transportation gets more complicated, so exploring that option is best left as extra credit homework for any readers of this thread.

Operational overhead costs for a Spinward X-Courier or Spinward Flex Courier would be ... Cr 7600 per round trip (or Cr 197,500 per year, including time off for annual overhaul maintenance), when also including berthing fees at the starport. Annual overhaul maintenance would cost Cr 110,886 per year (6G) or Cr 122,529 per year (5G) when including the price of maintaining the external L-Hyd drop tanks, which is less than the price of 2 unrefined fuel round trips or 1 refined fuel round trip. Assuming nothing goes wrong (always a big if!) and 1:1 pricing (for simplicity) ... a 5G Spinward X-Courier could clear a profit of Cr 2,179,971 per year, while a 6G Spinward Flex Courier could clear a profit of Cr 2,191,614 per year just on unrefined fuel deliveries in the 1000 ton L-Hyd drop tanks alone (and refined fuel would be Cr 12,179,971 (5G) and 12,191,614 (6G) respectively, an almost 6x increase for each!) assuming both starships receive their annual overhaul maintenance in-system and do not need to jump out to a different system for annual overhaul maintenance servicing.

In other words, both the 5G TL=11 Spinward X-Courier and also the 6G TL=13 Spinward Flex Courier are perfectly capable in their "stock" configurations of being operated as maneuver tugs for fuel barge duties hauling quantities of starship fuel at scale from gas giants to different orbits within a star system that is both economically useful for the starport (1000 tons of fuel per delivery every 2 weeks) and economical for the merchant line receiving the contract to supply the service, simply because of how efficiently both of these starships can be operated. Again, this kind of performance would be a "flex" move demonstrating the remarkably wide variety of uses that a standard design starship like these two could be put into contract service for when it comes to maneuver tug contract services.

And just in case anyone is thinking ... why would you need a STARship to provide fuel tanker service like this? ... bear in mind that not every system can build non-starships in their own system for non-military purposes (type A or B starport required) let alone maintain such non-starships adequately if they are imported (local tech level limitations). This combination of factors (starport type and local tech level) can yield a surprisingly large number of star systems where it would make sense for a merchant line to offer fuel tanker transport services from an in-system gas giant to the starport at the mainworld using a "common design" starship that can be maintained annually at a "nearby system" during part of the year and be contracted to return and resume fuel transport run cycles. With enough "copies" of the ships in the fuel delivery loop, it then becomes affordable to rotate individual starships out of the system periodically to send them out for maintenance while maintaining continuity of services.

Just another demonstration of how having powerful maneuver drives enables a starship to "do stuff" (and get paid for it!) in ways that a Far Trader or a Free Trader simply cannot keep up with or match. Put those big maneuver drives to WORK and you're almost guaranteed to see a tidy return on your investment!

 

[Silverhawk]

Actually, now that I think about the matter even more (you see what you people do to me?), there are 2.5 ways to cut down on manpower (and thus, life support) required per ton of fuel shipped ... keep the tankers under 200 tons (no need for engineers or medics aboard) ... or just go really big for economies of scale (which then creates massive drives that need lots of engineers for internal fuel tankage) ... or do a mix of both by using a tug+barge business model that basically amounts to small boat with small crew with powerful maneuver drives acting as a maneuver tug for a really large (unmanned) detachable cargo pod that is simply ALL fuel.


And just in case anyone is thinking ... why would you need a STARship to provide fuel tanker service like this? ... bear in mind that not every system can build non-starships in their own system for non-military purposes (type A or B starport required) let alone maintain such non-starships adequately if they are imported (local tech level limitations). This combination of factors (starport type and local tech level) can yield a surprisingly large number of star systems where it would make sense for a merchant line to offer fuel tanker transport services from an in-system gas giant to the starport at the mainworld using a "common design" starship that can be maintained annually at a "nearby system" during part of the year and be contracted to return and resume fuel transport run cycles. With enough "copies" of the ships in the fuel delivery loop, it then becomes affordable to rotate individual starships out of the system periodically to send them out for maintenance while maintaining continuity of services.

Just another demonstration of how having powerful maneuver drives enables a starship to "do stuff" (and get paid for it!) in ways that a Far Trader or a Free Trader simply cannot keep up with or match. Put those big maneuver drives to WORK and you're almost guaranteed to see a tidy return on your investment!

Presuming that one is following the RAW, the manpower requirement and the cost is going to be the two things that will keep the size of tankers down.

As for the reason to have jump capability that I can see is that in time of war you can remove the tankers and purification infrastructure. If the majority of the storage is in orbit you vent or destroy the fuel there before the enemy can secure it.

You are likely right about a smaller tug like vessel with high capacity maneuver drive to tow a larger amount of fuel to handle the manpower and cost issues.

 

[Spinward Flow]

Presuming that one is following the RAW, the manpower requirement and the cost is going to be the two things that will keep the size of tankers down.

Aye. Life support and crew salaries (and the tonnage for extra staterooms requiring more hull and drive displacement) are factors that can quickly eat into profit margins (how you measure "winning") in mercantile(ish) economic models ... particularly for internal fuel capacity oriented designs.

After demonstrating a Cr 7600 cost per 1000 tons of external fuel delivered business model (that works!) ... or basically a cost of Cr 7.6 per ton of fuel delivered, per delivery ... it starts getting hard to see how an internal fuel tanker business model would be able to compete with that kind of performance (and strictly speaking, there's room to reduce that cost even further by omitting the Gunner! ). Without a Gunner aboard, those overhead costs (life support plus salary plus berthing fees) nosedive down to being only Cr 5100 per 1000 tons of external fuel delivered ... or basically a cost of Cr 5.1 per ton of fuel delivered, per delivery. That's basically life support for 1 stateroom (Cr 2000 per 2 weeks), salary for 1 pilot (Cr 3000 per 2 weeks) and berthing fees (Cr 100 once each round trip).

I have a REALLY HARD TIME envisioning how a larger bulk internal fuel freighter is going to be able to beat those kinds of overhead cost numbers ... even when taking the "make it up in volume" approach using gigantic multi-kiloton sized supertankers (a massive investment in capital to buy, own and operate!) in the 10-50k ton range, even as non-starships. It probably CAN be done ... but exactly HOW is not immediately apparent to me ... although I'm sure the LBB5 crew requirements of 1 engineer per 100 tons of drives would help (10k non-starship with maneuver-1 (2%), power plant-1 (3% at TL=9-12) requires 500 tons of drives, meaning 1 chief engineer plus 4 more engineering staff) ... but then there's all the extra crew in the command department to think about, so it might not "balance out" until higher tonnages than 10k.

Like I said ... it's a challenge to come up with something better at 10k+ supertanker sizes than the more flexible "just use 10+ copies of those instead" where you aren't putting all your eggs in one basket (so to speak) and have a lot more operational flexibility when it comes to scaling up or down, not to mention mass production scale efficiencies at the shipyard(s) manufacturing the design(s) since it's cheaper to make multiple copies of a small ship than it is to order a single copy an incredibly huge ship. A 10k hull size in configuration: 4 costs MCr 600 before putting any drives into it ... and maneuver-1 would cost MCr 300 for 200 tons and power plant-1 would cost MCr 900 for 300 tons ... so the 10k hull already costs MCr 1800 in hull and drives before putting any crew spaces (bridge, computer, staterooms, etc.) into it.

Meanwhile ... the 5G TL=11 Spinward X-Courier would cost only MCr 1215.184 to buy 10 copies in mass production (plus an extra MCr 10.1 for ten 1000 ton L-Hyd drop tanks) ... while the 6G TL=13 Spinward Flex Courier would cost only MCr 1098.752 to buy 10 copies in mass production (plus an extra MCr 10.1 for ten 1000 ton L-Hyd drop tanks).

MCr 1800 for an incomplete 10k hull ... versus MCr 1225.284 (5G) or MCr 1108.852 (6G) for 10 starships that are completely built with each capable of hauling 1000 tons of fuel (10k tons total)?
NO CONTEST.

Even if you CAN get the life support/crew salary/berthing fees overhead costs fraction below that of the 194 ton "tug and barge" model, you still aren't going to be able to scale up large enough to break even when including the costs of annual overhaul maintenance (or you have to grow the internal tankage non-starship so large that it isn't even a "fair fight" anymore at 100k ton single non-starship vs 194 tons 100 starships kind of economies of scale). Now a megacorporation might be able to go so far as to reach for that kind of fuel fraction in a tanker design investment ... but "low end" operators (below megacorporation merchant lines, starport authorities serving world population codes of 8-, etc.) aren't going to be able to INVEST at the amounts of capital necessary to support such supertankers.

So ... once again ... Advantage: Spinward X-Courier and Spinward Flex Courier when it comes to the lower end market share operators.

As for the reason to have jump capability that I can see is that in time of war you can remove the tankers and purification infrastructure. If the majority of the storage is in orbit you vent or destroy the fuel there before the enemy can secure it.

Agreed.
Even if the jump capability is used only "once a year" to depart the system for maintenance (which might not be available locally) or even "never" (if maintenance IS available locally) ... being able to "retreat" out of system in the even of hostilities or even a demand for disaster relief operations in neighboring systems is still a valuable capacity to have built in, rather than being so hyper-specialized that if an invasion occurs you're stuck (and captured and put to work by and for the enemy) or if your capabilities would help out a neighboring system in need (disaster) your investments lack the means to "drop everything" and go assist them in any capacity whatsoever.

That flexibility is ... superfluous ... until it's not.

You are likely right about a smaller tug like vessel with high capacity maneuver drive to tow a larger amount of fuel to handle the manpower and cost issues.

Again ... until I started "playing with" the notion, I had a vague feeling it might be the case ... but only after actually doing some preliminary analysis (see above) do I start to see just how crushingly obvious the economic advantages of the different business models could be.

Could a variation of the Spinward X-Courier and Spinward Flex Courier be designed that is better optimized for shuttling 1000 ton L-Hyd drop tanks (that get retained all the time in regular service) around a star system?
Sure.
It would even be smaller than 194 tons.

134 tons * 0.17 = 22.78 tons
1000 tons + 134 tons = 1134 tons * 0.02 = 22.68 tons

So 134 tons is the minimum size of a 6G maneuver tug that can still manage to generate 1G with a 1000 ton external cargo load.
134 tons of non-starship would make the total displacement of drives smaller (22.78 tons maneuver, 24.12 tons power plant) and cheaper (MCr 11.39 maneuver, MCr 72.36 power plant) ... but at a cost of internal cargo capacity if keeping the jump drive, or expanding internal cargo capacity if building a non-starship (some of which could be devoted to installing a larger fuel purification plant for gas giant to moon shuttle operations). However, such a specialized design would necessarily lose a lot of flexibility, particularly in a non-starship configuration ... so as is always the case in engineering (and biology) ... how much specialization are you willing to tolerate in your operations, understanding that increased specialization carries its own set of external risks (when your operations become too inflexible to adapt to changing market conditions, such as war and disaster response)?

Like I said ... fun to think about ...

 

[Spinward Flow]

Could a variation of the Spinward X-Courier and Spinward Flex Courier be designed that is better optimized for shuttling 1000 ton L-Hyd drop tanks (that get retained all the time in regular service) around a star system?
Sure.

Upon even yet further reflection, it has occurred to me that this is the wrong perspective to take with respect to this issue ... of "right-sizing" the L-Hyd drop tanks to the starship hauling them.

I originally wrote the above under the assumption that "picking a nice round number like 1000 tons" was the correct way to approach the problem, since it would make comparisons of performance (and profit margins) easier to calculate and therefore more readily accessible and obvious. However, in cases where there is a ... mismatch ... between maximum external cargo capacity possible relative to the actual capacity being utilized, the correct answer is to adjust the size of the external container (the barge) rather than adjust the ship applying the maneuvering power (the tug). After all, it's far cheaper to choose a different size of L-Hyd drop tank to use than it is to design and build an entirely difference class of starship/non-starship (and hope there is enough demand for it to keep it in continuous mass production somewhere).

Consequently, what I should have been writing about is:

• 5G TL=11 Spinward X-Courier (MCr 121.5184) with external 1160 ton L-Hyd drop tank (MCr 1.17)
• 6G TL=13 Spinward Flex Courier (MCr 109.8752) with external 1450 ton L-Hyd drop tank (MCr 1.46)

The reason for using L-Hyd drop tanks (Cr 1000 per ton) instead of Exterior Demountable Tanks (Cr 500 per ton) is because L-Hyd drop tanks have no affect on streamlining of a ship, while Exterior Demountable Tanks render a ship+exterior tanks unstreamlined (and therefore a problem for gas giant fuel skimming operations), as per LBB A5, p14.

So in terms of 1:1 buy/sell price ratios for fuel, a 12-14 day round trip ferry run between a mainworld and a near gas giant (600,000,000km away) or a far gas giant (900,000,000km away) as per LBB2.81, p11 ... would yield the following:

• 5G TL=11 Spinward X-Courier (MCr 121.5184) with external 1160 ton L-Hyd drop tank (MCr 1.17)
  • Unrefined fuel: Cr 116,000 revenue, Cr 7600 cost (pilot+gunner = Cr 6.55 per ton)
    Cr 108,400 net profit per run (Cr 2,584,981 net profit per year @ 25 runs per year including annual overhaul maintenance)
  • Refined fuel: Cr 580,000 revenue, Cr 7600 cost (pilot+gunner = Cr 6.55 per ton)
    Cr 572,400 net profit per run (Cr 14,184,981 net profit per year @ 25 runs per year including annual overhaul maintenance)
• 6G TL=13 Spinward Flex Courier (MCr 109.8752) with external 1450 ton L-Hyd drop tank (MCr 1.46)
  • Unrefined fuel: Cr 145,000 revenue, Cr 7600 cost (pilot+gunner = Cr 5.24 per ton)
    Cr 137,400 net profit per run (Cr 3,321,624 net profit per year @ 25 runs per year including annual overhaul maintenance)
  • Refined fuel: Cr 725,000 revenue, Cr 7600 cost (pilot+gunner = Cr 5.24 per ton)
    Cr 717,400 net profit per run (Cr 17,821,624 net profit per year @ 25 runs per year including annual overhaul maintenance)

Now, one obvious (logistical) complication involved in all of this theorycrafting is the notion that these enormous L-Hyd drop tanks could be shipped interstellar by a 194 ton starship in an already pre-assembled state (which they can't, obviously) if contracted for fuel services in a star system which is incapable of producing L-Hyd drop tanks (that don't actually need to be dropped), either due to tech level and/or starport type limitations.

The solution for this particular problem is what amounts to essentially "pre-fab flat packs" of L-Hyd drop tank components produced where they can be built (at a reasonable price) for assembly in the target system where the fuel tanker service is needed. Such a pre-fabrication for export and then final assembly after import business model would then permit the movement of these L-Hyd drop tanks "in pieces" through jump space using a starship that ordinarily would not be able to "carry" such large (relative to the size of the starship) external tanks. If the parts to assemble amount to ~1 ton to ship for 10 tons of final fuel tank capacity (since the tanks themselves are mostly empty volume) then a mere 120 tons of major cargo (5G) or 150 tons of major cargo (6G) would need to be transported when rounding up to the nearest 10 tons as a major cargo shipment.

A 5G TL=11 Spinward X-Courier could transport all 120 tons of major cargo "pre-fab flat packs" involved could make a single export/import trip using 90 tons of external cargo capacity and 30 tons of internal cargo capacity.

6G TL=13 Spinward Flex Courier could transport all 150 tons of major cargo "pre-fab flat packs" involved but would need to make at least two trips due to the external 90 tons major cargo capacity during jump plus up to 40 tons internal cargo capacity being insufficient to transport all of the components for assembly in the destination system in a single export/import trip. Note that a 1300 L-Hyd drop tank would require only 130 tons of major cargo "pre-fab flat packs" to transport, which could be done in a single export/import trip to a destination system for final assembly.



Now, realistically speaking, I would fully expect any kind of long term fuel tanker contract to be handled on a subsidized (50% revenue rake) kind of basis, rather than as a private freelancer type of operation (let alone on a "catch as catch can" type of deal). The subsidy would necessarily mean that the government maintaining the starport essentially gets a "50% cut" of the fuel revenue flowing through the starport while the tanker service merchant line gets the other "50% cut" of the fuel revenues (and has to pay for all operational expenses and upkeep out of their 50% cut of the revenue). Essentially what happens then is that the subsidizing government buys fuel at 50% of cost and sells it through the starport at 100% cost, making a tidy bit of profit to help defray operating costs of a starport's budget along the way (not including the up front cost of buying the tanker ships in the first place). So a subsidy would represent a kind of public/private partnership of getting needed space economy infrastructure (fuel tanker transport services) "locked in" on long term contracts (40 years) and provide the kind of stability of supplies required to keep supplies of raw materials (starship fuel) flowing when the only obtainable source for those fuel supplies are "some distance" away from a mainworld that lacks water oceans for easy access to a fuel feedstock.

Depending on local conditions, it may be "cheaper" economically to set up a relay service of fuel tankers shuttling between orbits in order to "bucket brigade" a sufficient supply of starship fuel than attempting to "mine" and transport ice from a world's ice caps, or drill for subsurface water supplies or even rely on ice planetoid capture deliveries from an asteroid/planetoid belt beyond a star system's snow line getting hauled into orbit around a mainworld for exploitation by a starport's support facilities. In these "niche" markets for starport fuel supplies, the Spinward X-Courier and Spinward Flex Courier both make compelling cases as competitors for interplanetary bulk transport services at a reasonable cost that can be afforded by smaller populations and less wealthy starports, whether along the fringes or in the well settled and developed regions of Charted Space.