Efficient space only freighter design

[Condottiere]

Breakaway hull.

Self delivery.

 

[phavoc]

Another option.. detachable 'hulls' for each portion of cargo hold. Costs 1% of your cargo tonnage for the attachment gear, but then when you reach a atarport, each piece detaches and unloads/loads seperately as if they were independant ships.

Thats way too high a cost of course but it gives an alternate

Sort of like a LASH barge?

 

[J. L. Brown]

From the Cargo Loading rates thread:

Cargo Loading rates?

We recently ran into a scenario where it was important to know how long it took for a speculative cargo lot to arrive and then how long it took to load the cargo onto the ship. I could not find anything that discusses this. Does anyone know if/where something like this is addressed? The only...

forum.mongoosepublishing.com

For a Type A Starport:
Loading times of five minutes per ton are the norm – though specially equipped industrial hangers can reduce this to one minute per ton.

That should work especially on the big routes for LIFO.

I wonder if just making the entire cargo deck open like a gull wing door would avoid needing things on the outside and keep the ease of loading unloading both at dock and in open space.

I don't understand the loading/unloading rate of 'five minutes per dTon'. Imagine a megafreighter with a fully enclosed cargo bay 72 meters wide, 72 meters tall, and 290 meters long. The megafreighter is TL 9, so it has a 1-G Maneuver drive, and inertial compensators which can null-out up to 1-G of acceleration along its' long axis. The megafreighter is full of standardized cargo containers which are fastened together in a manner similar to our seafreight containers in use today; and it docks, nose in, to a dedicated cargo dock with a 72x72 passage for cargo and ~300 meters or more of linear space available.

Once the docking is secure, the cargo area is clear, and appropriate documents are signed and authenticated --
Set all 'deck plates' in the cargo area (to include the walls and ceiling) to negative 0.01 G, and to (for only a single combat round) compensate for 0.1 G of acceleration. For six seconds, the entire payload accelerates at 1 m/s, and ends up trundling out the front of the ship at 6 m/s; the whole hold is empty in less than 36 seconds.

The cargo area also sets the grav plates to 'compensate' for 0.1G axial acceleration (but in the opposite direction) and stops the whole shebang in one combat round.

At that point the entire outer surface of the cargo is accessible by cargo-handling equipment.

 

[Condottiere]

Mass driver set on low wattage; close to close range, go to dog fight mode, and eject a payload every six seconds.

For more accuracy, launch tube on low wattage, with a cycle rate of thirty six seconds.

 

[Vormaerin]

I don't understand the loading/unloading rate of 'five minutes per dTon'. Imagine a megafreighter with a fully enclosed cargo bay 72 meters wide, 72 meters tall, and 290 meters long. The megafreighter is TL 9, so it has a 1-G Maneuver drive, and inertial compensators which can null-out up to 1-G of acceleration along its' long axis. The megafreighter is full of standardized cargo containers which are fastened together in a manner similar to our seafreight containers in use today; and it docks, nose in, to a dedicated cargo dock with a 72x72 passage for cargo and ~300 meters or more of linear space available.

Once the docking is secure, the cargo area is clear, and appropriate documents are signed and authenticated --
Set all 'deck plates' in the cargo area (to include the walls and ceiling) to negative 0.01 G, and to (for only a single combat round) compensate for 0.1 G of acceleration. For six seconds, the entire payload accelerates at 1 m/s, and ends up trundling out the front of the ship at 6 m/s; the whole hold is empty in less than 36 seconds.

The cargo area also sets the grav plates to 'compensate' for 0.1G axial acceleration (but in the opposite direction) and stops the whole shebang in one combat round.

At that point the entire outer surface of the cargo is accessible by cargo-handling equipment.

Well, that's the core problem. We are trying to solve a low details problem with imaginary technology. We don't know the parameters of anti gravity technology. We don't know the structural and technological requirements of jump space worthy containers.

We don't even really know what kind of trade volumes we would need to be dealing with or the relative cost effectiveness of differing solutions.

So it's all gonna be "what feels right to you"

 

[phavoc]

I don't understand the loading/unloading rate of 'five minutes per dTon'. Imagine a megafreighter with a fully enclosed cargo bay 72 meters wide, 72 meters tall, and 290 meters long. The megafreighter is TL 9, so it has a 1-G Maneuver drive, and inertial compensators which can null-out up to 1-G of acceleration along its' long axis. The megafreighter is full of standardized cargo containers which are fastened together in a manner similar to our seafreight containers in use today; and it docks, nose in, to a dedicated cargo dock with a 72x72 passage for cargo and ~300 meters or more of linear space available.

Once the docking is secure, the cargo area is clear, and appropriate documents are signed and authenticated --
Set all 'deck plates' in the cargo area (to include the walls and ceiling) to negative 0.01 G, and to (for only a single combat round) compensate for 0.1 G of acceleration. For six seconds, the entire payload accelerates at 1 m/s, and ends up trundling out the front of the ship at 6 m/s; the whole hold is empty in less than 36 seconds.

The cargo area also sets the grav plates to 'compensate' for 0.1G axial acceleration (but in the opposite direction) and stops the whole shebang in one combat round.

At that point the entire outer surface of the cargo is accessible by cargo-handling equipment.

That's a clever way of doing things. I had not thought of trying to move containers horizontally using grav plating. I haven't seen that specifically anywhere, but when you are already magically manipulating gravity I suppose it's reasonable.

You'd still want to maintain a grav field fir cargo within the containers though - for most loads at least. They won't be secured to the floor/wall/ceiling like a perfect box. Most would still be palletizing for easier moment and loading/unloading. Making it zero g would be... messy for many loads. Though one could shrink wrap items to the pallet to maintain load consistency and togetherness and that would solve some problems.

The unloading part might be a bit of a challenge to move them lime that though - your dock would need at least that much space already emptied and then would have to process them to free up space to reload. There's efficient and then there is TOO efficient.

How would you handle stacked units? It sounds like your idea would have the forward portion of the ship capable of loading 4 to 5 containers wide and high?

 

[Nelphine]

Yeah i think the 5 minutes per dton is assuming a standard cargo bay door thats only one floor tall and 2-4 containers wide.

 

[MasterGwydion]

Gullwing doors would make for faster access, and in a 3-d environment you'd be able to put access on all sides. The limitation there is in a vacuum you'd have to make every load sealed against vacuum as well (depending on cargo) zero-g. So that gets us back to either space-worthy containers or else something down the middle. I had done some container write-ups before and come up with a one-time lining for a container to maintain vacuum integrity - opening it up would rip the seal. But I figured that was a relatively cheap way to use a standard container not meant for vacuum in a vacuum environment. That would offer you more way to access your load as long as the loads would accept that limitation.

Moving cargo around in-transit is possible - but also means you'd have to either have the space available (i.e. not running fully loaded) or else you leave the space available at all times to do that. Then if you used some sort of overhead system and played the tetris game in-transit you'd be able to move cargo around while in jump. You'd have to figure out your ship design to determine just how much wastage space would need to be reserved to do it. Assuming your loading/moving machinery was capable of it, your super-cargo could just program in the parameters and let the system do all the grunt work. Even if it took 3-5 days to do so you'd have more than enough time while in jump. There'd be additional wear and tear (i.e. maintenance costs that every merchant hates). Game-wise it's covered, but merchants skimp on maintenance as much as they can as it's credits not going into their pockets. That's been a truism since merchants were first created.

I'd think the UNREP system wouldn't work - mostly because that's not what its meant for. Yah, you can move stuff, but it's really meant to move from Ship A to Ship B - and not vice-versa. If you look at UNREP systems today you'll see that in every case the loading of ship A (the origin of the supplies) doesn't use UNREP to load itself. And the amounts moved while underway (excluding pumped fuel) are not huge. Ships don't resupply large quantities of anything other than fuel (Sacramento class AOE were replaced by Supply class... terrible name for the class if you ask me!). In space you don't have the same challenges you do with weather and waves, so I'd think it'd be more of extensible bridges from the supply ship to the receiving ship, and then just float/roll the pallets of equipment. Warships would not be loading 10Dton sized containers, but rather 1/2/3 dtons or even palletized cargo in 1/2dton increments. They are warships after all, not cargo ships. Plus I don't recall ever having seen a deckplan with the idea of placing cargo bays and reloading areas where you'd actually expect to see them to facillitate it. Real naval vessels don't do it either aside from the locations where you attach your fuel and lines for winching the loads across.

Again, most of this has nothing to do with the game. It's just providing background with an eye towards the details. Probably gonna be lots of handwavium and moving on the pew-pew or the talky-talky part that most games are all about.

I would have to agree with the handwaviam on the exact details of how a 53rd century UNREP system works just based on it's description. It moves a non-specified quantity of items by general volume per hour. It states that it moves basically everything. This implies to Me that Our understanding of 21st century UNREP technology has no bering on how 53rd century UNREP systems work, because you are correct. By Our understanding of current UNREP technologies, it makes no sense. It also shows that none of the artists who build deckplans have any idea of how to move cargo with current UNREP systems. lol

 

[J. L. Brown]

That's a clever way of doing things. I had not thought of trying to move containers horizontally using grav plating. I haven't seen that specifically anywhere, but when you are already magically manipulating gravity I suppose it's reasonable.

It is part of the 'Inertial compensator' function of grav plating. At higher TLs the grav plates can completely negate 6+ Gs of acceleration or random buffeting; but the implications of the ability to 'bias' the inertial compensators like this is (like many things in sci-fi) completely over looked. Another one is valves for handling fluids simply cease to be a thing when gravitics is reliable and cheap enough.

You'd still want to maintain a grav field fir cargo within the containers though - for most loads at least. They won't be secured to the floor/wall/ceiling like a perfect box. Most would still be palletizing for easier moment and loading/unloading. Making it zero g would be... messy for many loads. Though one could shrink wrap items to the pallet to maintain load consistency and togetherness and that would solve some problems.

Modern sea-freight containers lock together to form rigid structures; there are simple mechanical 'locks' facing each direction at all the corners. They are manually activated, and keep containers immobile in rough seas -- but they need to be released before cranes can move them. It is the very much the same concept as shrink-wrapping pallets. I think that by the time we are routinely using gravitics technology, we will be packing for cargo to be handled by gravitics technology; and sufficient packing material inside the container is probably part of that.

The unloading part might be a bit of a challenge to move them lime that though - your dock would need at least that much space already emptied and then would have to process them to free up space to reload. There's efficient and then there is TOO efficient.

If there is no room on the dock, then the mega-freighter is not unloading because there is nowhere to unload to. Note that the dock might choose some other orientation to accelerate the cargo; steering it around to an appropriate warehouse or processing area. This sort of stuff truly seems trivial at TL 9; and if I am paying 25000 Cr for 4.5m^2 of floor space it damn well better be worth it.

How would you handle stacked units? It sounds like your idea would have the forward portion of the ship capable of loading 4 to 5 containers wide and high?

I chose these numbers out of the air; I figured a single cargo bay with 100k dTons of containers. If each cargo container is 3m wide and 3m tall, then the block of containers is 24 wide & tall; and 72m length gives ~25000 dTons -- so the cargo is four 25k cubes linked together end-to-end.

 

[Nelphine]

My initial thought for megafreighters is much longer and not as tall, under the assumption that stations want to accomodate ships of all sizes without wasting docking bays when a megafreighter isnt there.

So the smallest container is 3 long x 1.5 wide x 1.5 tall.

One floor is 3m tall, so, 1 dton of container(s) is 3 long x 3 tall x 1.5 wide.

Under my earlier discussion, im assuming that the small world stops on the way will need to be able to use 500 dtons. So the smallest block a megafreighter will use is 500 dtons. These are for class b starports, so they cant handle much height.

So 6 m tall (2) 15m wide (10) 75m long (25).

These class be starports also probably cant accomodate 75m long at once except at a final warehouse, so its probably broken further into 15m long chunks. Any corridors they need to go into to get to final warehouse wont accomodate 15m wide, so it may further be broken into 3m wide chunks.

I agree completely on the mechanical locks at the corners of each container, although id assume they are operable from a distance, so that the 3m width doesnt impact unloading.

So that means the smallest you're actually unloading is 100 dtons at a time, 6m tall x 15m wide x 15m long.

But, by having remote locking mechanisms, you can change the size of the unloading chunk based on yhe starport you're at.

500 dtons is 6x15x75.

1000 dtons is either 12x15x75 or 6x30x75.

That means 2000 dtons is a natural block as well at 12x30x75.

That means my 10k freighter, probably isnt 10k. Its, whatever size gets 8k cargo hold, for 4 2000 dton blocks, with a cargo hold 12x30x300.

Then the megafreighter is 12 times that, 96k cargo hold, with 48 2000 dton blocks, 24x60x900.

Hurrah! Ive figured out the dimensions of my megafreighter, as well as the tonnage, instead of using an atbitrary 10k and 100k dtons!

 

[Condottiere]

You have to keep in mind one thing.

Do we build the infrastructure to accommodate containers, or design containers to fit within existing infrastructure?

 

[J. L. Brown]

My initial thought for megafreighters is much longer and not as tall, under the assumption that stations want to accomodate ships of all sizes without wasting docking bays when a megafreighter isnt there.

I do not envision mega-freighters using docking bays at all; they are simply too big. And every minute not spent in J-space is a minute of time wasted not-making-money -- so waiting for a docking bay, maneuvering into it, waiting for the doors to seal, and all that is simply avoided. The mega-freighter just docks to the exterior of the highport in those odd cases where it is not docking directly to a dedicated cargo-handling port 100d trailing of a major fuel source.

So the smallest container is 3 long x 1.5 wide x 1.5 tall.

One floor is 3m tall, so, 1 dton of container(s) is 3 long x 3 tall x 1.5 wide.

The subsidized merchant, and some other common tramp freighter designs IIRC, use double-height cargo decks, so containers up to 6m tall are possible. I tend to think that containers would be big, and tramps would tend to handle uncontainerized cargo -- while mega-freighters are likely to ignore any cargo of less than 100 dTons, and are almost certainly not going to be built to handle 1 dTon containers since they are optimized for bigger stuff.

Under my earlier discussion, im assuming that the small world stops on the way will need to be able to use 500 dtons. So the smallest block a megafreighter will use is 500 dtons. These are for class b starports, so they cant handle much height.

So 6 m tall (2) 15m wide (10) 75m long (25).

These class be starports also probably cant accomodate 75m long at once except at a final warehouse, so its probably broken further into 15m long chunks. Any corridors they need to go into to get to final warehouse wont accomodate 15m wide, so it may further be broken into 3m wide chunks.

A starport which is designed to handle cargo will be designed to be able to move the cargo between ship and warehouse without excessive changes in the configuration of the cargo. Since it is not unusual for a few worlds in each subsector to need to handle millions of dTons per day, 15m wide corridors will be common, and probably a bit small for cargo handling purposes.

My mega-freighter example earlier was nothing of the sort -- it delivered only 100k dTons (four 25k dTon cubes) of cargo. An actual mega-freighter would deliver ten times as much, and the question then becomes whether or not dinky little 25k dTon cubes are worth messing with.

I agree completely on the mechanical locks at the corners of each container, although id assume they are operable from a distance, so that the 3m width doesnt impact unloading.

So that means the smallest you're actually unloading is 100 dtons at a time, 6m tall x 15m wide x 15m long.

But, by having remote locking mechanisms, you can change the size of the unloading chunk based on yhe starport you're at.

500 dtons is 6x15x75.

1000 dtons is either 12x15x75 or 6x30x75.

That means 4000 is a natural block as well at 12x30x75.

That means my 10k freighter, ptobably isnt 10k. Its, whatever size gets 8k cargo hold, for 2 4000 dton blocks, with a cargo hold 12x30x150.

Then the megafreighter is 12 times that, 96k cargo hold, with 24 4000 dton blocks, 24x60x450.

Hurrah! Ive figured out the dimensions of my megafreighter, as well as the tonnage, instead of using an atbitrary 10k and 100k dtons!

It's good that you have a standard which works and makes in-universe sense for you; having this sort of background detail worked out helps make the universe a bit more 'real' to the players, even if they never encounter it directly. That said, I tend to think that standard freight loads will not be much bigger in their largest dimension than they are in their smallest -- if nothing else than to minimize the cross-section of the freighters, warehouses, and cargo handling equipment.

For example, the 12x30x75 (2000 dTons) is six times longer than it is tall; you could halve the floor space required by making it 24m tall (24m x 30m x 37.5m). Wrapping a corridor or warehouse around the short one requires (12x30 + 12x30 + 30x75 + 30x75 + 12x75 + 12x75) = 7020m^2 of material; the taller 'cube' requires only 5490 m^2. The game abstracts this away, but I think the real economics would tend to favor the taller stacks -- especially since gravitics technology is so widespread and inexpensive at the 'Imperial Average' of TL 12.

 

[Nelphine]

Hum. While I've designed 12 million dton ships, i tend to think of them as the exception - that particular ship was specifically a luxurious tourist trap (complete with pools, movie theatre, opera theatre).

Given warships are 'standard' at less than 100k dtons, i wouldnt expect freighters to absolutely dwarf them. And i wouldnt expect there to be that many worlds that can even justify the 96k dton of cargo. So to me, anything larger than that is going to be highly specialized, for a specific pair of planets. With specialization, and cargo at that scale, the infrastructure would also be custom designed around it.

The 8k and 96k ive described are intended to be the generic ones that can go between any pair of billion+ planet AND still dock at every million+/class B starport along the way.

Its the intention to match with the little ones that im using as the basis for this. Im trying to design the uniquitous freighter that would be a common sight all over charted space.

 

[phavoc]

Keep in mind that the idea of containerization is to minimize additional costs when moving the cargo. Giant containers seem like a good idea for some things, but not for others. A good question to ask yourself is how would you get that thing down to the planet, loaded on a cargo delivery vehicle and then get it to the local Galactic Discount Warehouse so the goods on board can be sold? There are some ways to get it down, and one could do all translating in orbit. But from the methods that have been created over the last 4-5 decades there seem to be some operational gaps.

I know that containers use manually installed twistlock to link/lock a container on a trailer or to each other. They are cheap and easy to handle manually. I suppose maglocks or some physical lock mechanism could be used in their place. So long as costs were equivalent then I see no reason not to assume they have become standard.

All good ideas though. Very interesting discussion.

 

[Nelphine]

So ive designed my 8k freighter. However, i think ive made it overly luxurious. Its 12k total, because i like round numbers. If you made a 12k freighter how much cargo would you end up with?

 

[J. L. Brown]

I'm working with the assumed shipping containers being 3m wide, 3m tall, and either 6m, 9m, or 12m long -- for 4 dTon, 6 dTon, and 8 dTon sizes.
I am ALSO assuming that the corner locks in use are structurally very strong, and groups of containers which are locked together are essentially one solid object, and loading/unloading operations tend to handle large blocks of containers rather than individual containers -- individual containers are handled only to tear-down or assemble 'cubes', which are things done in a warehouse.

An eight container wide by eight container tall square would be 16 deck-squares or 24m wide; if it was the same length then it would be a 1024 dTon cube. If we figure that 2.4% of that volume is wasted as container material and gaps between containers, then we have 1000 dTons of cargo -- which seems like a neat place to standardize medium-size freighters. A mega-freighter would probably want to avoid fiddling about with small units, and would probably prefer to arrange these 1000 dTon cubes of attached containers into a 3 x 3 x 3 'cube of cubes' -- which hold 27000 dTons of containerized cargo and are 72m along each edge.

Going that route, I tried to design a J-3 M-1 Freighter to haul 3x 1000 dTon cubes in an internal cargo bay, with a 1.5 meter access walkway around three sides of each cube (about 1175 dTons per cube) -- with 8 dTon containers, that means being able to access and inspect every single container while in jump-space. My design is 6000 dTons, is heavily automated with robots and repair-drones substituting for most crew, and carries up to 12 people (including crew) in double occupancy middle passage staterooms. It is not a perfect design; a J-2 ship would probably be more efficient.

 

[Nelphine]

Hum. So you have 3 cubes, that are.. lengthwise? So 24x24x72?

I dont like the height and width being so high for a standard block, i just dont see smaller starports being able to accomodate that easily, but i get the overall goal. And since my standard block is 500 tons instead of 1000 (and then my standard chunk for a freighter is 4 such blocks fit into a 2000 ton rectangle)t, its reasonable to have a different view.

Id personally do 4 cubes in a square, so 24x48x48, rather than 3 long (assuming we ignore my previous concern about height/width), but thats based on my 500/2000 standard block/chunk design.

My 12000 is J2, and has 440 tons of tetris space plus 8000 tons of actual expected cargo space in a line 12x30x300. So 66-70% effeciency. Implies ~1200 tons of stuff that isn't directly cargo space or jump fuel.

Yours is 6500, J3, has .. 933 tons of tetris space if i understand correctly (i don't like the layout though, inspection without the ability to move it isnt worth it for me. Instead i would take that space and clump it big enough that i could move something if needed. Minor nitpick), and 3000 tons of actual cargo, in a line 24x24x72. So 45-60% effeciency. Implies 700 tons of things that arent directly cargo or jump fuel.

I think you could reduce extra space you've added. Ive only added like 6% of my cargo hold for tetris space, youve added almost 30%. You could almost fit a full block instead.

My ship is almost twice the size, so lots of perctage based equipment will be bigger, so 700->1200 seems reasonable.

So maybe mine doesnt have as much waste as i was afraid of.

Edit: no its 600, not 700 for yours. And since J3 is a big chunk of that, it isnt doubling going to my ship (only J2). Maybe i do have too much extra 'luxuries'.

 

[J. L. Brown]

Hum. So you have 3 cubes, that are.. lengthwise? So 24x24x72?

I dont like the height and width being so high for a standard block, i just dont see smaller starports being able to accomodate that easily, but i get the overall goal. And since my standard block is 500 tons instead of 1000 (and then my standard chunk for a freighter is 4 such blocks fit into a 2000 ton rectangle)t, its reasonable to have a different view.

Id personally do 4 cubes in a square, so 24x48x48, rather than 3 long (assuming we ignore my previous concern about height/width), but thats based on my 500/2000 standard block/chunk design.

My 12000 is J2, and has 440 tons of tetris space plus 8000 tons of actual expected cargo space in a line 12x30x300. So 66-70% effeciency. Implies ~1200 tons of stuff that isn't directly cargo space or jump fuel.

Yours is 6500, J3, has .. 933 tons of tetris space if i understand correctly (i don't like the layout though, inspection without the ability to move it isnt worth it for me. Instead i would take that space and clump it big enough that i could move something if needed. Minor nitpick), and 3000 tons of actual cargo, in a line 24x24x72. So 45-60% effeciency. Implies 700 tons of things that arent directly cargo or jump fuel.

I think you could reduce extra space you've added. Ive only added like 6% of my cargo hold for tetris space, youve added almost 30%. You could almost fit a full block instead.

My ship is almost twice the size, so lots of perctage based equipment will be bigger, so 700->1200 seems reasonable.

So maybe mine doesnt have as much waste as i was afraid of.

Edit: no its 600, not 700 for yours. And since J3 is a big chunk of that, it isnt doubling going to my ship (only J2). Maybe i do have too much extra 'luxuries'.

Yeah, I have definitely chosen some non-optimal options. I have 510 dTons of J-fuel (enough for a 1 parsec jump; I am building at TL 15 and took 'decreased fuel' three times) in a dedicated tank. I then have two separate 510 dTon capacity fuel/cargo tanks -- so I can fill them with fuel for J-3, or use one for tetris cargo & J-2, or use both for tetris cargo and J-1. That added flexibility costs me ~50.5 dTons.

Likewise, the access-ways around the cubes costs me a bunch. Doing away with those entirely would save me 464 dTons, which is pretty huge -- but I like them to account for clearance when moving the cubes in and out, and because being able to get at a potentially problematic container mid-flight seems like a good idea. Still, it is a big performance hit, and it almost certainly is not worth the credits... although I am looking at a 2 GCr+ ship, so protecting that investment also seems prudent. I guess this comes down to how often a ship is lost to something that access to containers would have prevented. I have 10 single beam turrets just as a defensive option. There are NO auxiliary craft, or considerations for redundancy or prtotection against anything but small-time piracy.

I have common areas, emergency low-berths, and biosphere for every passenger on board -- which is not strictly necessary, but the biosphere does lower operating costs. Repair drones handle most Engineering and Mechanical tasks, and I have two one over-crowded brigs with no life support for storing the off-duty utility/steward/whatever robots. I think a dedicated J-2 ship with less wasted space could come in below 5k dTons for 3k dTons of cargo.

My one concession to optimization is using Advanced Batteries to power the Jump Drive; that lets me get by with a smaller Power Plant, as long as I have 4 hours (easily done while still in jump) to charge the batteries between jumps. And, of course, the idea that all of the 'cubes' can be safely loaded or unloaded with simple gravitics in less than a minute -- the 'tetris' cargo will be a real pain, though. I wanted to work out a scheme whereby I could use the space in the fuel/cargo areas for another cube instead of tetris cargo, but I have not managed it yet -- adding 2 dTons to each would mean another cube could just barely fit. Hmm, maybe I will need to try it out....

So, if I make the fuel/cargo bays 512 dTons each, I get a few extra weeks of general operation fuel for the powerplant, and a fourth cube will just barely fit -- but there is no access to the sides, or to the rear-echelon containers at all. Some fuel processors have been swapped out for UNREP, so the ship can purify 520 dTons of fuel per day, or take on 520 dTons of fuel per hour. Fully fuelling the ship will take ~3 hours, during which time the cubes can all be unloaded (and others loaded if they were waiting), and passengers disembarked. If refined fuel is available, then new passengers can embark and the ship is ready to depart -- else it parks somewhere out of the way for three days refining fuel before leaving.

 

[Geir]

I think I already mentioned that I think standard containers should correspond with the sizes of freight and speculative trade lots: 5- and 10-ton, with 1-ton lots being "irregular". Whether these would need to be 10 or 20 squares on a deck plan is possibly an overly literal approach though, and given the convention of representing a 4-ton standard stateroom as 6 squares, perhaps it would make sense to make the "standard" 5-dton container 8 squares (2 x 4) and the 10-dton 16 (2 x 8). If deck height was actually 3 metres (maybe less because of ceiling and floor considerations), it is also likely (or convenient) that the containers corresponding more in height to the current "standard" 2.59 or 2.9 metre tall containers. Plus, it would be almost exactly a 20-foot or 40-foot container in length if we go with 6 or 12 meter lengths (and make them physically somewhere between the 'standard' 2.44 metres and 3 so they fit through a 3 metre-wide hatch).

This is convenient for designing Adventurer-class starships and deck plans. Megafreighters, may be another story, but why not stay consistent?

The T5 standard container illustrated is a 3 dton model, but that doesn't work with MgT v2 trade rules... and I don't exactly know how to use T5's trade rules, but it seems to assume everything is one ton... and I can't find anything that indicates anything else... no, I really don't get it.

 

[J. L. Brown]

Speculative trade lots, and quite a bit of freight that tramp vessels deal with, is not usually containerized at all; mostly it is break-bulk, weirdly shaped packages and crates, individual herd animals, or (at best) palletized -- very much a 'play tetris in order to get it stowed' type of cargo. As the author of the thread posited, it is the mid-scale and mega-freighters which deal in heavily containerized cargo; and those (mostly off-screen) 'big fish' of the cargo trade are the ones who shape the standards.

4 dTon staterooms include corridors, galleys, common areas, life support, and so forth -- they represent all 'the living space for the crew and passengers'; so the three dTons allocated on deck plans reflect that.