Megafreighters

[Reynard]

We've casually discussed this from time to time and I put some extra thought to the topic. Where are all the really big interstellar freighters? We know about of adventure class scales usually 1000-5000 ton ranges but they really can't serve the needs of worlds with any population or sizable trade. Something larger is hauling vast quantities of goods that should dwarf the minds of most. Even ships in the tens of thousands of dton wouldn't carry much to service entire worlds.

I looked at current naval freighters for inspiration to function and size. As you can imagine, there are lots of hauling specific cargos to smaller ports for local distribution and easily supported by many world ports. An average size freighter is in the tens of thousands of Dead Weight Tons and do a fair job to supply a nation or continent but still you need many to provide anything close to meet demands. Of late, their is a class of super freighters built to efficiently haul huge tonnage of cargo at one time greatly increasing trade supply.

I wanted an example to compare and use a representative called the Maersk Triple E. It has a 55,000 ton displacement 400x59x73 meters. I fudged a bit for a conversion of 127, 615 dtons. It carries 18,000 Twenty foot Equivalent Containers or about 52,2000 dtons in it's structure. A TEU is about 6.2x2.4x2.4 meters or 2.9 dtons and is a standard container you see hauled on tractor-trailers though the 1 TEU container is preferred. That's a lot of trucks fanning out from the port! Problem is these sizes need special deep port facilities to handle them and those are rare in the world. In the end, you still get a lot of freight into an are at one time.

Now that's to service continents but Starports service entire worlds. This means freighters need to be scaled more but that can also mean incredible scales bordering on Star Wars multi kilometer vessels. An average megafrieghter could be smaller and serve to haul a sizable amount of goods while being manageable. For this example I chose a 500,000 dton vessel as a starter.

Megafreighter, automated 500,000 dton 94,458 MCr.
Hull: Dispersed, light, non-gravity
Armor: 0
Manuever: 1
Jump: 3
Power plant: TL 12 fusion
Fuel: 1 x J1, 4 weeks operation
Bridge: Standard
Computer: 15 bis
Software: Maneuver/0, Library, Jump control/3
Sensors: Civilian
Staterooms: 10
Cargo: 280,389 dtons
Options: Docking Clamp Type II, Virtual crew/0 (Pilot, astrogator, Remote operator/engineering), Repair drones.

Fully automated to shuttle cargo between large population worlds with A and B Highports able to support and service such behemoths. A dedicated fuel facility is a must. Highguard page 39 (cargo crane) suggests standard containers at 32 and 65 dtons. These are transferred to and from an orbital warehouse and distributed to other ships or planetside distribution facilities.

Astrogation updates are calculated and transmitted to the ship from the port. Major engineering duties and inspections are performed by port teams while unloading and loading. The repair drones handle routine and minor repairs during the voyage controlled by the central virtual engineer. Staterooms are for temporary inspectors and special teams during flights. The bridge allows emergency manual control.

Variant ships are Jump 1 and Jump 2 with the extra space for more cargo capacity.

 

[AnotherDilbert]

There is no real need for massive ships. Unlike watercraft, Traveller ships are not more economically efficient the bigger they are. Starships don't get all that much more efficient after 10 kDt or so.

So, instead of a single 500 kDt ship jumping a particular route every week you can have many smaller ships, jumping every few hours. Not only will total freight time be lower, the system will be more flexible as smaller ships can be reassigned as trade routes change.

Example: 500 kDt vs. 50 kDt:

500 kDt:

50 kDt:

P.S. You might want to look over the cost of your ship, just the jump drive should cost more than GCr 38. Your ship has a default crew of about 2000, automating them with a m/15 computer is a bit much.

 

[Reynard]

Sorry I goofed up the whole concept. Thought it was a cool idea.

 

[NOLATrav]

@Reynard, I rather like your take on the megafreighter. Nice to have a concrete idea of something that’s always been vague background fluff in my campaign.

Probably I would have a skeleton crew and some rudimentary defenses against pirates, but what’s a thousand dtons amongst friends?

 

[MonkeyX]

It’s possible to imagine a ship that is effectively a large spine with cargo sections attached to them that can actually deprecate and fly down from orbit, with each bay carrying a few hundred tons.

 

[AnotherDilbert]

Sorry I goofed up the whole concept. Thought it was a cool idea.

Why would you be sorry for playing your game?

 

[Condottiere]

Identify where you can economize with economies of scale, which is the point with megafreighters.

You can do the Heighliner model, and have cargo added and subtratced at each stop, or invest in long range jump drives for a more point to point connection, following large trade flows.

 

[Anonymous]

There is no real need for massive ships. Unlike watercraft, Traveller ships are not more economically efficient the bigger they are. Starships don't get all that much more efficient after 10 kDt or so.

This is true (for classic which I know, unsure about Mongoose), but how does the starport infrastructure work? Freight loading times, for example?

If you're shipping across a border (say Imperial to Vargyr or something) - or maybe between worlds of different law levels - you also have customs and immigration protocols to deal with. Independent traders are going to be checked very carefully but treaties probably allow a limited number of larger ships in recognised freight line service through so long as the crew stay on board during the starport layover.

 

[phavoc]

Conceptually I don't think it's a bad idea. And it certainly IS a mega-freighter. But it may be TOO much of a mega-freighter. Remember that merchants look for COST to transport a good above all else. Experiments with fast freighters in the modern age have all failed. Failed as in them being considered commercial successes. Even the Concorde, which transported people, was a limited success due to the very high cost.

Crew's on commercial ships definitely should not be done according to the formula's in the book. Today merchant ships of 50-100,000 DWT (dead weight tons) are crewed by 30-35 people. There isn't much for them to do other than steer, watch the engines and manage the ship entering/leaving port. Everything else is automated.

Like AnotherDilbert says, I'd refactor your design and bring it down to just 50k dtons and see what it looks like there. Freighters need to be much larger in order to transport the commerce in Traveller - the little 2,000 ton ships won't cut it and free traders are just semi-trucks. There should be the equivalent ship-type of a train (which carries 300 containers at a time), smaller cargo ships serving smaller routes (up to 500 containers) and then the bigger boys (500 containers and up). To be honest I'm not sure what an upper limit would actually be, but maybe if you capped it out at around 3k - 5k containers? With each container being 10 Dtons.

Since we are talking space operations the idea of carrying cargo in larger containers makes some sense. Space is a hazardous environment unlike what they experience for sea-going. However to MonkeyX point, I don't think it would be economical to have each container it's own flyable unit. That would add a lot of cost to something that gets used only rarely. It seems much cheaper to have a single cargo lighter that just carries the container down to the ground. That way it could be used for many containers and spread it's cost out. Plus the LASH concept was tried back in the 60s & 70s and it turned out to be not so cost effective. If you have a well-organized ground cargo transportation environment the costs for LASH barges was simply too great. Plus the ships did not carry them as effectively as it could regular cargo. In this particular case the cost for flight machinery would be the most likely culprit to push them over the edge.

Identify where you can economize with economies of scale, which is the point with megafreighters.

You can do the Heighliner model, and have cargo added and subtratced at each stop, or invest in long range jump drives for a more point to point connection, following large trade flows.

Condottiere brings up a good point. Just how IS the cargo network designed? Would you have a hub-and-spoke network where ships go from Point A to Point B and rarely, if ever, deviate from this? Or would you have them on a circuit, either regular or otherwise, to keep them in a rotation of sorts? I suspect it would be both. For the largest routes you should expect to see them moving between the larger ports and let cargo's moving on to get picked up by the next ship in the chain. IF there was another world nearby then maybe a circuit. But the larger ships would only ply the bigger routes. The intermediate ones would most likely be the type to do the rotation, and smaller deliveries would be handled by free traders and the like. If you study today's cargo system you will see one that probably is nearly the same for the future. It's very much optimized for good service at the cheapest rate. At least the overall system is. Once you hit a country's borders all bets are off.

 

[Anonymous]

That crew figure is a little out-dated for a newer ship, but I accept that not all ships are new. A Triple E has about 10-15 crew @ 200K+ deadweight.

The x-boat network seems like a good example of how freight routes will work. Due to nature of jump, not all worlds are connected for comms, so they sure won't be connected for freight.

You'll have pendulum routes linking A starports or maybe following x-boat routes, and then smaller ships hauling from those hubs.

However, in old traveller, the Imperium strictly controlled high jump in civilian usage. I don't know if j4 would be allowed in the general case but J5 certainly isn't.

We really to know how loading works too. Today, loading time is a big factor in freight cost.

edit: 1 TEU is 39m3, so a 20K TEU container ship (about the biggest today) has just under 60K dtons of cargo assuming traveller still uses 13.5m3 per dton.

 

[AnotherDilbert]

This is true (for classic which I know, unsure about Mongoose), but how does the starport infrastructure work? Freight loading times, for example?

I have no idea about official figures, but I blithely assume that a starport that regularly accept a particular size of ship, can unload it in a day or two.

Now, if a large freighter tries to use a tiny starport, then it's a different story...

 

[phavoc]

That crew figure is a little out-dated for a newer ship, but I accept that not all ships are new. A Triple E has about 10-15 crew @ 200K+ deadweight.

The x-boat network seems like a good example of how freight routes will work. Due to nature of jump, not all worlds are connected for comms, so they sure won't be connected for freight.

You'll have pendulum routes linking A starports or maybe following x-boat routes, and then smaller ships hauling from those hubs.

However, in old traveller, the Imperium strictly controlled high jump in civilian usage. I don't know if j4 would be allowed in the general case but J5 certainly isn't.

We really to know how loading works too. Today, loading time is a big factor in freight cost.

edit: 1 TEU is 39m3, so a 20K TEU container ship (about the biggest today) has just under 60K dtons of cargo assuming traveller still uses 13.5m3 per dton.

X-boat network is a good rule of thumb, but remember it's designed for information flow. You can have two roughly equivalent worlds next to each other (well, light years apart, but you know what I mean), and only one of them is slated to be part of the X-boat network while the other isn't. Commerce will flow based upon consumer demand. And we already know the makeup of the map as far as starports and stuff goes doesn't always make a lot of sense (random dice rolls!). I would expect it, were it reality, to be rather complicated transit network, but also a relatively stable one. Much like air and freight travel is today. It's dynamic, but very stable and predictable.

I'm not sure what you mean by high jump in civilian usage. Do you mean the Imperium restricted civilian usage of J-4 or greater? I dont' recall seeing that, but then again there's a lot of material to cover. It would be something that I don't see as part of the Imperial power. Civilians would need high jump to cross some of the vaster distances just like the military. In MGT2 I would expect to see fewer J-6 ships due to the exhorbant costs of them. Liners with J-6 passage would be essentially corpsicle storage ships, as you'd have to cram so many people aboard to justify the costs. Only the very wealthy could afford the travel, and I'd hazard a guess that a passenger liner for J-6 travel would be the odd duck out.

Assuming a ship with 60Kdtons of cargo onboard, that would equate to 60 MCr per trip, assuming it was fully loaded. Ships of that size won't be carrying speculative cargo. It will all be paid for at the bulk rate. Assuming two rips a month, that 120 MCr a month, or 1,440 MCr per year in gross revenue. Optimization could squeeze out another trip, but for the sake of the math that's where you'd be. AnotherDilbert assume just 80% utilization rates, so that would reduce it to 1,152 MCr per year. If Traveller ships are expected to last decades or more, the ROI would be rather hefty (though taxes and such could take a bite out of that...)

 

[AnotherDilbert]

AnotherDilbert assume just 80% utilization rates, ...

That is just a default to have something to start with.

Real capacity utilisation would certainly be lower than 100%.

 

[Sigtrygg]

The x-boat network was constructed on top of the existing trade network.

The Traveller Adventure has an excellent chapter on trade routes within the Aramis subsector that can be used as a starting point for trade route additions to the existing x-boat network.

Trade and commerce in the well developed sectors of the Imperium will be very different to the trade and commerce practices in the frontier sectors.

Setting canon tells us that jump 6 x-boats and drop tank civilian ships are in use in the interior sectors:

Officials of the General Shipyards on Regina today announced that they have completed negotiations with Tukera Lines to locally manufacture L-Hyd drop tanks for use on high-capacity commercial vessels.
…
L-Hyd drop ships have only been in service for the last dozen years in the interior, being made possible by recent advances in the field of capacitor engineering, a joint press release explained.
…
from the Imperial core that a decision has been made to deploy Jump-6 L-Hyd drop tank express boats on all major express routes.

A megafreighter jump frame that carries subcraft makes for an excellent naval auxiliary in times of war - just swap the cargo carriers for SDBs, fighters, battle riders to get them closer to the hostilities where they can be transferred to military tenders...

 

[Anonymous]

I can't find the exact thing I first read, but I had a quick look in a traveller wiki (http://wiki.travellerrpg.com/Jump_Drive) for jump and it has this.

Most civilian starships have a jump rating of 1 or 2, with rare vessels equipped for express work carrying systems capable of 3 or 4; such ships operate for premium fees on long routes where speed is of the essence. Long routes tolerating longer delivery times use the usual jump1, but additional tankage to permit crossing rifts or voids to other lucrative destinations. It is so uncommon for a civilian ship to mount J-5 or J-6 that it draws the attention of Imperial authority as a curiosity worthy of review, if not close monitoring.

So that's not an outright ban on J5, but it looks like they might "prefer" you use J1 or J2 and make 3-5 jumps. It seems you might run into many bureaucratic obstacles with a J5 drive like permits, buying parts etc. Unless you're a megacorp with a permit from the duke and your own J-drive spare part factory.

X-boats aren't civilian so I don't have a problem with J-6 X-boats.

3rd Imperium is kinda control-freaky, but it's been many years and many Traveller editions, and I don't know what's what anymore!

 

[phavoc]

The x-boat network was constructed on top of the existing trade network.

The Traveller Adventure has an excellent chapter on trade routes within the Aramis subsector that can be used as a starting point for trade route additions to the existing x-boat network.

Trade and commerce in the well developed sectors of the Imperium will be very different to the trade and commerce practices in the frontier sectors.

Setting canon tells us that jump 6 x-boats and drop tank civilian ships are in use in the interior sectors:

Officials of the General Shipyards on Regina today announced that they have completed negotiations with Tukera Lines to locally manufacture L-Hyd drop tanks for use on high-capacity commercial vessels.
…
L-Hyd drop ships have only been in service for the last dozen years in the interior, being made possible by recent advances in the field of capacitor engineering, a joint press release explained.
…
from the Imperial core that a decision has been made to deploy Jump-6 L-Hyd drop tank express boats on all major express routes.

A megafreighter jump frame that carries subcraft makes for an excellent naval auxiliary in times of war - just swap the cargo carriers for SDBs, fighters, battle riders to get them closer to the hostilities where they can be transferred to military tenders...

Ah, the old Traveller Adventure. I do recall the Tukera lines write-up. It helped provide more detail.

That was near the initial creation of the drop tank idea. And there was the snippet about drop tanks, but ship designs were still listed as being dependent upon their normal internal fuel stores. The didn't have ships that had jump ratings greater than the fuel they carried (even, I think, with the sample ship that was built using the LBB rules if I recall correctly).

In theory the smaller ships could simply be carried as cargo on the megafreighter. Using freighters as temporary military transports is a time-honored tradition. Though usually when carried as freight the crews were dispatched separately and then got their equipment later.

 

[Sigtrygg]

GURPS Far Trader went to the logical conclusion that LASH trading would be common for bulk trade - Lighter aboard ship.

The jump frame jump between the 100D limits of worlds, the cargo is offloaded either to shuttles for carrying to the world or by actually using a 'powered cargo pod' - the lighter itself which is basically the cheapest shuttle you can build - note it doesn't have to be small, the lighter could be a 1000t ship built to carry the cargo and passengers (carried for this bit of the tip in couches rather than staterooms).

The jump frame takes on board fuel, lighters or cargo pods for the next world, and embarks passengers to their stateroom (note you could have a passenger lighter that has staterooms etc for passenger transport).

The obvious advantage of this system is you can make a jump much more often, three per month rather than two per month.

The disadvantage is the infrastructure required - highports, tankers, shuttles.

IMHO such a system works well in developed subsectors, but I had a hard time agreeing with the GT FT authors that such a system would be common within the Spinward Marches.

 

[phavoc]

GURPS Far Trader went to the logical conclusion that LASH trading would be common for bulk trade - Lighter aboard ship.

The jump frame jump between the 100D limits of worlds, the cargo is offloaded either to shuttles for carrying to the world or by actually using a 'powered cargo pod' - the lighter itself which is basically the cheapest shuttle you can build - note it doesn't have to be small, the lighter could be a 1000t ship built to carry the cargo and passengers (carried for this bit of the tip in couches rather than staterooms).

The jump frame takes on board fuel, lighters or cargo pods for the next world, and embarks passengers to their stateroom (note you could have a passenger lighter that has staterooms etc for passenger transport).

The obvious advantage of this system is you can make a jump much more often, three per month rather than two per month.

The disadvantage is the infrastructure required - highports, tankers, shuttles.

IMHO such a system works well in developed subsectors, but I had a hard time agreeing with the GT FT authors that such a system would be common within the Spinward Marches.

Seems to me that the bigger freighters wouldn't be visiting smaller worlds ports, so the LASH would be a waste (much like it was when it first came out). In a busy system I could see the freighter port and warehousing at the 95-98D limit (wouldn't be at the 100D since you want a little warning of any incoming ship from jump space). There they arrive and drop off bulk cargo, refuel and take on the new cargo and head out for their next stop. The freight then gets separated into going on to new destinations or put on lighters to be delivered to planetary destinations. Cargo meant for in-system would be delivered to smaller in-system freighters.

Question would be more along the lines of where do you put the passenger terminal? It makes sense to keep the highport orbiting the planet, but freight is different so storing it out of the orbital areas is reasonable. It might sit in a warehouse for weeks waiting on transshipment using hub-and-spoke concepts. Passengers though would want to be closer to a planet if they had to wait for their next liner, so they might be at the highport. Makes for an interesting system infrastructure question.

The thing to remember about LASH is the usage. If you only use those engines and such once a week, that's a bad ROI because your amoritization isn't spread out enough. It was the same concept that sunk the original LASH concept ships. The barges and associated equipment required too much maintenance to justify their savings. That and the nature of transport (and better adoption of containerization) left them in their dust. I don't think we will see another radical change that would improve upon the efficiency of containers for non-bulk products (or specialized ones).

 

[Reynard]

Thing I'm seeing is people are thinking very small as if adventure class scale is adequate to serve an entire planet with significant population (7+). Biggest freight vessels in Traders and Gunboats are the 'Large' Freighter and the Modular Clipper both at 2000 tons. The Large Freighter carries 1004 ton cargo plus 24 passengers while the Modular Clipper hauls a possible 1024 tons of cargo. Convert that to the TEU measure and you have the freighter moving the equivalent of 173 full size tractor trailers and the clipper doing 176. How many freight trailers to you see on the highways around your homes? 2000 ton starships are space step-up vans better serving low and very low population worlds with few settlements.


I wish there were more examples of freighters in the tens of thousands of tons but they would still carry an insignificant load to adequately serve all the territories of well populated planets on a national/continental level. Superfreighters on Earth don't service New York, London and Bejing they supply The US, the UK and China. Now think about Earth as a space power with access to an actual starport and you were doing business with several other worlds of similar populations plus lesser colonies. Those superfreighters as starships would not keep up with the scale of trade of an entire planet. We build superfreighters today because trade is no longer local. 10,000 tractor trailer loads at a time is a lot of product moved in one haul rather than dozens or hundreds of trips requiring a lot more crew and service facilities. All this can be scaled up again to planetwide economies which would need many hundreds or thousands of ships clogging a starport just for main trade. Megafreighters haul planetary scale loads to dedicated ports that can transfer, store and distribute cargo on grand scales along main trade routes which can pass loads to smaller and smaller vessels for secondary and tertiary routes. A ship bringing in almost 49,000 tractor trailer loads is definitely significant.

My idea for these freighters would be akin to the X-boat system for hauling a lot of trade product up and down a commercial main connected by important worlds that have the starport capacity and resources. You need population of at least 7+, A and B highports so the ships are always close to 100D mark and microgravity makes transfer efficient and quick, reliable security plus sustainable fuel sources for refined fuel. A great class A port over a desert world with no gas giant is worthless to feed these goliaths. These ports are hubs for lesser A and B ports as well as other even smaller ports.

Space is vast and space travel should be grand.

 

[Anonymous]

Earth ships 200 million shipping containers a year.

Each container is a 20 foot TEU which is 3 dtons.

Assuming a ship can jump every other week, Earth requires 23 Traveller mega dtons of space freighter cargo capacity.

(200*10^6*3/26) = 23m

That's just containers, and not bulk like iron and oil.

https://www.billiebox.co.uk/facts-about-shipping-containers/