Most Efficient Ship by TL for Cargo to X Parsecs

[vegas]

If we look at the passenger volumes on the major trade routes calculated by GT Far Trader, we are looking at thousands of passengers per day, so worrying about not utilising the stewards fully is probably a minor problem.

That depends how realistic you want your economic model to be.

TLDR: I tend to use 80% capacity utilization as a rule of thumb to account for economic fluctuations as well as unplanned maintenance downtime.

GT:FT doesn't have any method for economic fluctuation, it just calculates an average. Economies generally, and trade and travel especially, fluctuate substantially with economic cycles. Couple that with the large fixed capital costs involved, it will be difficult for supply to adjust through those fluctuations resulting in a boom/bust business cycle. We see that a lot in real world capital intensive industries.

Industry participants react to such an environment. If haulers can't change supply quickly, the big ones will size their fleets so that they can remain profitable on average. That will mean they aren't sized to fulfill all the demand in booms and let the independents pick that up, but they will suffer less in the busts as they gain relative market share versus indies.

Amongst this macro economic fluctuation, it will be difficult for individual ships to stay 100% utilized in their holds and staterooms as the demand and supply an individual ship sees changes with time depending on how much business is available for indies and how many indies are around to fulfill it. In booms, expect every ship to operate near capacity, but in busts, every ship will have a hard time filling up until enough indies are driven out of a given market. Hence, 100% utilization of capacity whether it is ships or stewards and staterooms will be unrealistic to achieve. I like assume 80% to account for that.

 

[whartung]

Lighter Aboard Ship - basically the jump ship carries cargo modules that can be rapidly offloaded to port while being refuel and picking up cargo. passengers and possibly a replacement crew for the next destination so there is no week long wait between jumps.

This can save a few days, but it's certainly no instant turn around.

The best way to do this is to have a freight depot outside of the 100D of the main planet. Perhaps a large space station, or a built up asteroid.

The reason is because you want the ship to jump in and be where it needs to be without having to move (much). With the 100D limitation for a planet, you have that travel time, to and fro, to make up for.

In deep space, it's less of an issue. Now you only really need to compensate for the 32 hour jump window of arrival. Which can certainly affect travel time, just not as much, depending on the orbital velocity. But it should be less than the 100D travel time.

Then, you need to have the cargo and crews there waiting for the ship.

When the ship arrives, you can meet the ship half way, bring the ship in to the station, or ship the cargo and fuel out to the ship. Clearly there are going to be load limitations, how many ships can be handled simultaneously, number of shuttles available, etc. etc.

The fundamental point is to reduce the insystem travel time to reduce overall turn around time given the nature of jump drives.

During seasons when jump shadows of the main star become a problem, you can put the freight depot on the other side of the shadow. This obviously increases the FREIGHT turn around (it has to go to/from the planet to the depot), but retains the ship turn around efficiency.

Obviously, only at certain volumes does this make sense me thinks. The other solution for ship down time is simply have more ships so the freight is always efficiently moving.

 

[Grav_Moped]

Agreed.




If we look at the passenger volumes on the major trade routes calculated by GT Far Trader, we are looking at thousands of passengers per day, so worrying about not utilising the stewards fully is probably a minor problem.

Fair enough.

Somewhere I need to come up with what happens to costs for shipping that isn't on the major trade routes. This exercise is about tech level effects, and I'll have to work out when and why the highest TL ships (and in a LBB2 3I universe, that's going to be TL-15) might not be available for a given market.

The obvious reason is that they're too big. The tricky part is to figure out what "big enough" is.

LBB5 shipping costs are far less influenced by ship size.

 

[Proneutron]

Couple that with the large fixed capital costs involved, it will be difficult for supply to adjust through those fluctuations resulting in a boom/bust business cycle. We see that a lot in real world capital intensive industries.

Something South West tried to compensate for by originally going with an all 737 fleet. Much easier to adjust to fluctuations in volume and routes with many small planes than fewer, much larger types.

 

[vegas]

Yes and no. The main benefit of having a single airplane type is cost, not capital flexibility. 1 plane means less training time for pilots and mechanics, buying in bulk, easier inventory management, that kind of thing. That is the big reason.

Sure there is some benefit on ease to swap planes to routes, because you always will be able to maintain every plane at any gate you fly to (because they are all the same) but that is a second-order benefit compared to the cost savings from a simplified fleet.

And it doesn't help at all with the main problem of fixed capital which is once you have the plane, you have to fly it or you are losing your return on capital. If travel demand goes down (which is known to happen, ahem covid, cough housing bust, cough 9/11) then that plane sits and you are eating those costs.

 

[Proneutron]

And it doesn't help at all with the main problem of fixed capital which is once you have the plane, you have to fly it or you are losing your return on capital.

Incorrect. It helps a TREMENDOUS amount with this. Compare a fleet of all 747s vs 737s in US market. You are going to be able to make MORE on your fixed capital with the 737s as you will be able to find more routes to run them at capacity than the 747s.

 

[Grav_Moped]

That depends how realistic you want your economic model to be.

TLDR: I tend to use 80% capacity utilization as a rule of thumb to account for economic fluctuations as well as unplanned maintenance downtime.

GT:FT doesn't have any method for economic fluctuation, it just calculates an average. Economies generally, and trade and travel especially, fluctuate substantially with economic cycles. Couple that with the large fixed capital costs involved, it will be difficult for supply to adjust through those fluctuations resulting in a boom/bust business cycle. We see that a lot in real world capital intensive industries.

Industry participants react to such an environment. If haulers can't change supply quickly, the big ones will size their fleets so that they can remain profitable on average. That will mean they aren't sized to fulfill all the demand in booms and let the independents pick that up, but they will suffer less in the busts as they gain relative market share versus indies.

Amongst this macro economic fluctuation, it will be difficult for individual ships to stay 100% utilized in their holds and staterooms as the demand and supply an individual ship sees changes with time depending on how much business is available for indies and how many indies are around to fulfill it. In booms, expect every ship to operate near capacity, but in busts, every ship will have a hard time filling up until enough indies are driven out of a given market. Hence, 100% utilization of capacity whether it is ships or stewards and staterooms will be unrealistic to achieve. I like assume 80% to account for that.

The other way to address it is to undersupply the market. There will indeed be a tendency toward oversupply due to "tragedy of the commons" effects, but given the costs involved, it may be more cost-effective to run ships that always fill their holds but leave some cargo behind.

So what you get is the ships that almost always run at 100% capacity but only cover 100% of the market during the downswings. During booms, they only capture 80% of it and leave the rest to free traders.

 

[Grav_Moped]

This is the cost multiplier for shipping in a single jump compared to shipping by the lowest-cost method, by Tech Level.

This still assumes the conventional 14-day jump cycle is used.
EDIT: At TL-13 and 14, lowest cost J-1 is still the TL-11 2000Td ship; I'd used the higher-cost TL-13 and 14 ones instead. Fixed. Other minor edits.

Cost of Jump-n instead of lowest-cost method to n parsecs:

Dist TL-9    TL-10  TL-11   TL-12    TL-13   TL-14   TL-15
1    1.00    1.00    1.00    1.00    1.00    1.00    1.00
2    1.01    1.00    1.00    1.00    1.00    1.00    1.00
3    3.04    1.09    1.35    1.22    1.14    1.14    1.00
4     x      3.07    3.21    2.16    2.16    1.83    1.08
5     x       x     31.83   31.83    5.14    5.14    3.03
6     x       x       x       x       x       x      5.37

x indicates that Jump-n is not available at that Tech Level

Note that the J-5 ship at TL-11 has only 7 tons payload out of 400Td, which explains the high multiplier.
The J-5 ship at TL-13 is significantly better, but it isn't until TL-15 that J5 becomes relatively cheap.

The reason that Jump-2 costs exactly the same as the lowest-cost method to 2 parsecs from TL-10 onward is that Jump-2 is the lowest-cost method to go 2 parsecs. But not by much. At TL-9, the difference is less than 1%; at TL-10, about 4%; at TL-11 through 14, just under 4%.

At TL-15, Jump-1, Jump-2, and Jump-3 are each the cheapest way to get to 1,2, and 3 parsecs respectively. Jump-4 is close (only 8% higher than 2J2).

I may come back at this with "Cost of Jump-n" vs "Cost of fastest means to n parsecs", but that gets complicated because if you're allowing multiple consecutive jumps (either by Long Ships or just gas-and-go), you also have to allow all ships to gas-and-go -- which, while sensible, violates in-universe standard practices. (It'd also require me to tweak my spreadsheets and recalculate everything, so I'm disinclined to do that just now.)

 

[kilemall]

No, obviously not.



No, obviously not.


Mass exists, whether we bother with the details or not. CT spacecraft don't bother with the tiny detail of mass, but that does not mean it does not exist, just that is it simplified away.


In my game cargoes are measured in displacement tons, fitting in cargo holds measured in displacement tons. A displacement ton of cargo is presumably limited by volume and mass, just like a current cargo container, but I don't generally bother to go into that much detail, since CT ships don't bother with mass.


If we sneak a peek at MT where this is clearly resolved, cargo holds and cargoes are measured in volume, and a displacement ton of cargo is rated at a nominal 1000 kg/m³.

So, a displacement ton of cargo hold can carry a lot more than 1000 kg, but much less than 270000 kg (14 m³ of gold).
Just like a standard TEU container (33.2 m³≈2,4 Dt and 24000 kg) can hold a lot more than 2400 kg, but a lot less than 640000 kg (solid gold).

That's fine if you rule it that for YTU, it just isn't RAW and people are entitled to argue it's a standard.

 

[kilemall]

On calculating steward/high passenger business model, don't forget to factor in the steward's quarters and life support as a cost/lost revenue opportunity.


Also, servicing debt is just that much worse for a larger/longer jump ship. That should be a factor set for examination all it's own.

 

[Condottiere]

Since steward services would be part of fixed operating costs, as you don't usually adjust per number of passengers.

Unless this aspect becomes part of the gig economy.

 

[Grav_Moped]

On calculating steward/high passenger business model, don't forget to factor in the steward's quarters and life support as a cost/lost revenue opportunity.

The formulas I gave included that (it's in the "passenger-cost * 1.125" term for the stateroom, and the Cr188).

That is to say, you calculate:
1. what a stateroom costs, financed, per two weeks.
2. what life support for 1 person costs for two weeks.
(These two make up the "passenger cost".)
and
3. What you pay a steward for two weeks. (Divide that by 8 passengers and that's the Cr188)

Each middle passenger costs you 1. plus 2. per two weeks.
Each high passenger costs you 1. plus 2. plus another (1/8 of (1. plus 2. plus 3.)). Possibly more than 1/8 of that if you don't have enough high passengers to fully utilize your steward crew.

Also, servicing debt is just that much worse for a larger/longer jump ship. That should be a factor set for examination all it's own.

I'm not sure that needs to be extracted, as it's already an element of the cost per cargo ton per jump figure.

One thing I'll need to work out in terms of availability is whether any given world has enough cargo volume to fill one of these most-efficient ships (that is, if big ships with partially-full holds get outcompeted by smaller ones running at capacity).

 

[Grav_Moped]

Since steward services would be part of fixed operating costs, as you don't usually adjust per number of passengers.

Unless this aspect becomes part of the gig economy.

On large liners (which are the most-efficient-ships with most of their payload space committed to staterooms), they're proportional to the number of desired high passengers. And that number is probably reasonably predictable over large numbers of trips.

Or you can guess at an average number of passengers per steward (1-8, average of 4.5) and allocate the cost of the steward among those.

 

[Straybow]

No, obviously not [a flat 1000 kg ton].

No, obviously not [a 14 m³ packed solid with gold bars].

But why not? That's the elephant in the room.

Mass exists, whether we bother with the details or not. CT spacecraft don't bother with the tiny detail of mass, but that does not mean it does not exist, just that is it simplified away.

Mass is not a tiny detail. It is what breaks essentially all the shipbuilding and trade rules in Traveller. LBBs essentially ignored mass. MT nodded at mass, but they handwaved the actual conflict between mass and dT volume that breaks the trade model. It seems everything since MT has gone back to Sgt. Schultz-like "I see nothing!"

In my game cargoes are measured in displacement tons, fitting in cargo holds measured in displacement tons. A displacement ton of cargo is presumably limited by volume and mass, just like a current cargo container, but I don't generally bother to go into that much detail, since CT ships don't bother with mass.

So shipbuilding, cargo, and trade models remain broken. Why bother with tweaking the system if nothing is actually fixed?

If we sneak a peek at MT where this is clearly resolved, cargo holds and cargoes are measured in volume, and a displacement ton of cargo is rated at a nominal 1000 kg/m³.

Hardly. They put a line in the rules saying that dT can be a 1 ton/m³, but then ignore the implications in trade item costs. Are you buying a ton mass, or a variable lot in tons that may be 1-14 tons, or some other unmentioned quantity that becomes another arbitrary "standard" that isn't in any way standardized? (10 tons? I remember seeing a reference to 11 tons?)

So, a displacement ton of cargo hold can carry a lot more than 1000 kg, but much less than 270000 kg (14 m³ of gold).
Just like a standard TEU container (33.2 m³≈2,4 Dt and 24000 kg) can hold a lot more than 2400 kg, but a lot less than 640000 kg (solid gold).

The load limit on TEU is based on the design of the box. It isn't strong enough to hold more than 24 tons gross without potential damage to the container in shipment or handling. The 40' version is nominally considered 2 TEU, but it is limited to 30½ tons gross rather than 48 tons. The limit is also based on the structural strength of the box.

There are also limits to the dock's handling equipment. The TEU can be lifted at the extension limits of the crane. The double TEU can probably be lifted at limit at any major port, but go off the beaten path and who knows what you'll find. Heavier objects require special instructions wherever you go.

Notice that nobody calls it a "ton" when it isn't, in fact, a ton mass or a register ton that is somewhat close to a ton mass when loaded in a seaworthy manner. The TEU didn't become a new "register ton" with a different size and mass limit superseding the ton mass. It is just a set of dimensional standards for stackable shipping containers.

The only way to "fix" the shipbuilding, cargo, and trade models is to scrap it and start over with actual mass and sensible volume units. Using vL in non-starship construction (MT? Striker? I don't have anything beyond CT) got about halfway there, but was then abandoned.

 

[Straybow]

Observations:
For this set, the only one for which a standard hull makes sense is the TL-9 J-2 400Td ship (and none of the J-1 ships). Weirdly, the 800 and 1000Td standard hulls only save build time, not money.

[snip] Revised observation: 2J1 is significantly cheaper at TL-9 and 10. Then 1J2 is cheaper until...

EXCEPT for the 5000Td TL-15 JD-Z ship. That one is a LOT more cost-effective than the TL-15 JD-W ship jumping twice. It's the Magic of Z!

This is an artifact of having hand-crafted tables rather than mathematical equations. Apart from 100, there are no odd-multiple standard hulls. The drive potential table skips by 200 from 200 to 1000, and then by thousands, which is really kludgy ("don't want to put the effort into making it more detailed"). As somebody pointed out, the drive potential table changed in the '81 revision.

That's the other part that has to be fixed to make shipbuilding, cargo, and trade actually work.

 

[kilemall]

This is an artifact of having hand-crafted tables rather than mathematical equations. Apart from 100, there are no odd-multiple standard hulls. The drive potential table skips by 200 from 200 to 1000, and then by thousands, which is really kludgy ("don't want to put the effort into making it more detailed"). As somebody pointed out, the drive potential table changed in the '81 revision.

That's the other part that has to be fixed to make shipbuilding, cargo, and trade actually work.

The eternal struggle of do you sim first or do you story first.

 

[Grav_Moped]

This is an artifact of having hand-crafted tables rather than mathematical equations. Apart from 100, there are no odd-multiple standard hulls. The drive potential table skips by 200 from 200 to 1000, and then by thousands, which is really kludgy ("don't want to put the effort into making it more detailed"). As somebody pointed out, the drive potential table changed in the '81 revision.

That's the other part that has to be fixed to make shipbuilding, cargo, and trade actually work.

The drive potential table is mostly consistent, with a couple of odd jumps (Z Drives being the most obvious, but I remember finding a couple of non-linearities when I manually graphed size vs. performance back in the early-mid 1980s. The non-linearity might have been partially for copyright reasons (formulae can't be copyrighted, while a chart that wasn't generated by a formula can be -- yes, I know you could write a formula for it, but it'd be more of a function than a formula). And as I understand it, the lack of granularity (particularly above 1000Td) wasn't laziness, it's that they didn't have room on the page for more.

What gets weird is the drive tonnage below Size A. You can't extrapolate a drive that gives 1G in a 100Td hull -- it would be zero tons.


The other thing I want to do as a digression from this is to work out exactly what combinations of drives work in each of the standard hulls. The clear intent of standard hulls is to force specific design choices. I want to know what they were.

How much did the standard hulls change between the '77 edition and the '80 one -- or did they? I get a feeling that this is something that was just tweaked only enough to accommodate the edition changes rather than being carefully thought out.

 

[kilemall]

The drive potential table is mostly consistent, with a couple of odd jumps (Z Drives being the most obvious, but I remember finding a couple of non-linearities when I manually graphed size vs. performance back in the early-mid 1980s.

What gets weird is the drive tonnage below Size A. You can't extrapolate a drive that gives 1G in a 100Td hull -- it would be zero tons.


The other thing I want to do as a digression from this is to work out exactly what combinations of drives work in each of the standard hulls. The clear intent of standard hulls is to force specific design choices. I want to know what they were.

I would presume it's mostly jump/m-drive combo vs. non-starship higher PP/m-drive.

 

[Grav_Moped]

Ran the numbers on standard hulls:
EDIT: Corrected 600Td - it does the J3 1G of the canon Type M Subsidized Liner exactly.

Standard Hulls:
Number following "w" after performance ratings is number of Td wasted. 
Size:   Performs   Performs  Performs  Performs  Performs  Performs  Valid Perfect Fits
 100Td  J0 6G      J2 2G     J4 0G (not valid)                       J2 2G. J0 6G no room for stateroom 
 200Td  J0 4G      J1 1G     J2 0Gw3                                 J0 4G, J1 1G
 400Td  J0 5G      J1 3Gw5   J2 2Gw5                                 J0 5G (non-starship)
 600Td  J0 6Gw25   J1 6Gw5   J2 3Gw5   J3 1Gw0                       J3 1G
 800Td  J0 6Gw75   J1 6Gw50  J2 6Gw5   J3 5Gw23  J4 4G               J4 4G
1000Td  J0 6Gw110  J1 6Gw55  J2 6Gw15  J3 3Gw10  J4 1Gw3             None

Conclusions:
Only the 100, 200, and 800Td standard hulls have drive bays that exactly fit a valid set of starship drives.
The 400Td hull is sized for a 5G non-starship, but no starships.

In other words, half of the standard hulls do not have drive bays that exactly fit a valid set of starship drives. That is, there could never be a standard starship class that would have used those hulls. CORRECTION: 600Td hull fits J3 1G exactly.

So, why are they standard?

 

[boomslang]

So, why are they standard?

Because they did not playtest it enough? Because they did not care?

My long-standing theory: In the LBBs, Traveller starships appear to be originally conceived of primarily as a mechanism of convenience for transporting mercenaries and the criminally-inclined between the starports of mainworlds so that they may further their post-service careers of "misbehavior"; any other use -- mercantile activity, exploration, prospecting & mining, pleasure cruises, and what have you -- was considered incidental to the intended gameplay and was therefore relatively neglected in the design and operations rules.

Have you compared the standard hulls to the 1977 B2 design process, wherein power plants need only match M-drives, and J-drives are not constrained by power plant model? Left as an exercise for the reader...