General Math Sucks: Cargo Containers

[whartung]

However, weight is the enemy of aerospace performance.

However, the Traveller universe is not an "aerospace" problem. It powers right through aerospace. Lightweight is no longer king in a Traveller setting.

Doesn't mean the containers are made of lead, but just that it's simply not the primary problem to solve.

 

[Rigel Stardin]

@aramis This is what I came up with using the Gurp info gain from @Tjonesio.

​

I'm not going to go into all the math I did to come up with these figures. I just going to give you an overview.

The designer at GURP decide 445 kg was a good number for determining the weight of the container by cubic meters.
I subtract .2m from the Exterior Measurements to get the Capacity because this was the difference I saw in real world container.
The weight of the container is 445 kg times the length, doubled if the container is wider than 2.4 meters.
I settled on 2.7 because it allow something like a pallet jack/forklift to get under the container and still have room for lighting without raising the deck.

Modern: Based on Modern Cargo Containers.
Seen in Game: Up until this post, these were the two common type containers on deckplans.
My Design: I'm not sure about the 1 Ton Container being my design but I'm sure 1/2 ton is. It allow you two stack to containers in one space without raising the ceiling.
Modified GURP: I subtracted .3 from the height.

I rounded all numbers to the closest decimal one place out?

 

[tjoneslo]

Cargo Container/meta - Traveller

wiki.travellerrpg.com

I put these together using GURPS Vehicle Builder and GURPS Vehicles rules if you would like to compare with your math. They are, to the best of my abilities, the detailed version of the containers from GT:Far Trader.

 

[Rigel Stardin]

After thought: This just popped into my head. 1.5 by 1.5m square of floor space could technically hold 4-5 Metric tons using these stats. This would allow that 16 ton G-Carrier to be parked in your cargo hold.

Math: up to 6 tons per square.

 

[Rigel Stardin]

@tjoneslo I'm trying to post some ships at the moment. That's enough math for me at the moment. Plus, I dont have a GURP's Traveller rulebook.

 

[Grav_Moped]

Each container is supposed to allow at least 5 deep vertical stacking, so they have to be stressed for the frame to handle about 141,000 kg. Note that some modern postpanamax stack upwards of 9 deep... for just shy of 254,000 kg on the frame... in theory. (In practice, it's possible to have latches.
Plus, some of the wells are 45', with bars that the containers can lock into at 2.5' in from the end.

And they're designed for a 1g environment, for obvious reasons.

Far Future TEUs will need to be able to handle up to 6G briefly and 2G sustained, in at least two orientations. Unless artificial gravity and inertial compensation are a side-effect of the maneuver drive function...

 

[Condottiere]

I don't think there is a golden mean for containerization, but there is the eighty/twenty rule.

So the containers should be sized to fit eighty percent of likely cargo.

One difference in Traveller is that what might be suitable for whatever goes for road or rail transport, is likely a subcontainer for space transport, and that likely scales up a couple of more categories.

 

[aramis]

And they're designed for a 1g environment, for obvious reasons.

Far Future TEUs will need to be able to handle up to 6G briefly and 2G sustained, in at least two orientations. Unless artificial gravity and inertial compensation are a side-effect of the maneuver drive function...

Not a side effect; a designed in portion. At least, in Mega and later. Separate system, needs to be installed. G's compensated are TL minus nine.

 

[Rigel Stardin]

If someone can compile a list of the height of the cargo holds of every ship's design as cargo vessel in travel we would have our answer. And the ships I'm talking about are the ones listed in the LBB.

Standard Deck Height: 3 Meters
Empress: 4.5 Meters
Subsidized Merchant: 6 Meter

The ones missing are:

Far Trader (Beowulf)
Subsidized Liner

If these two turn out to be the same height I've already seen then, we'll have our answer.

 

[AnotherDilbert]

I would allow loading 10 tons per Td, myself, based upon TTNE's recalculation threshold... with the resulting payload being max-tare.

TNE explicitly uses 1 tonne/m³ = 14 tonnes per displacement ton:

TNE FF&S, p14:
Calculate two masses, loaded and empty. Loaded includes a full load of fuel, full load of cargo (assume 1 tonne per m³), and all carried craft and vehicles on board.

The default assumed mass of a spacecraft (incl. very light fuel) is 10 tonnes per displacement tonnes, but recalculation threshold is 14.5 tonnes per displacement ton:

TNE FF&S, p69:
Spacecraft require (for the sake of simplicity) 10 tonnes of thrust per displacement ton to achieve an acceleration of 1G. Spacecraft with a final mass of more than 15 times (rounding fractions to the nearest whole number) their hull rate (in displacement tons) should recalculate their acceleration based on the actual thrust-to-mass ratio, dividing thrust (in tonnes) by mass (in tonnes) to determine acceleration in Gs.

Cargo in TNE, just as in MT and CT Striker, is assumed to be a nominal 1 tonne per m³.

 

[Spinward Flow]

Far Trader (Beowulf)

I thought the Beowulf was an A1 Free Trader, not an A2 Far Trader.

At the very least, the LBB S7 Far Trader has a 3 meter deck height cargo hold. The deck over the cargo hold is the fuel tank, and the ship only has 2 decks.

 

[Rigel Stardin]

Yeah you're right. Sorry for the mistake.