Cargo Capacity and volume and mass

[Rupert]

That works, and gives roughly neutral buoyancy. It is way past overloaded for most wheeled and tracked ground vehicles in Mongoose Supplement 6 Military Vehicles, which cannot drive on normal roads past around 450kg/m^3, depending on the exact configuration.

1 tonne per m^3 will result in substantial empty space when carrying heavier things like mined ore, but will allow lighter things like manufactured goods to be stuffed in as tightly as can be managed. That is good information, thank you.

A historical rule of thumb for non-containerised general cargo was one ton per 100 cubic feet, or about a tonne per 3 m³.

For what it's worth, this is what GURPS Vehicles, and thus GURPS Traveller assumes. This gives about 5 tons (or tonnes, we're not being precise here) per displacement ton (which is also about 500 cubic feet, which is convenient given GURPS' insistence on using US customary measures).

I tend to look at the 1 tonne per cubic metre of Striker, MT, & TNE as a maximum safe load - more than that and the referee gets to start doing evil things to your ship. Likewise if a very high density load (gold, uranium, etc.) is stacked up in one spot, over-stressing the deck. Most cargo is going to be well under the density of water, just as most is today (note that a fully loaded 20-foot container is less dense than water).

 

[TamsinP]

The WW2 Liberty Ships had a cargo hold volume of 4380 NRT* (12,404 m^3) with a DWT of 10865 tons; if the hold is completely filled, that would be a maximum of 2.48 tons per NRT.

* 1 NRT = 100 cubic feet.

 

[whartung]

Well, according to this diagram:

Modern density is 336kg/m^3.

 

[Rupert]

The WW2 Liberty Ships had a cargo hold volume of 4380 NRT* (12,404 m^3) with a DWT of 10865 tons; if the hold is completely filled, that would be a maximum of 2.48 tons per NRT.

* 1 NRT = 100 cubic feet.

DWT includes fuel, water, etc. though (and they had a 1,700 ton fuel capacity). Also, their actual total cargo volume was 562,608 ft3 'grain' (i.e. for things like grain that flow into all the spaces between frames, etc.

 

[Rupert]

Well, according to this diagram:

Modern density is 336kg/m^3.

That's for a 40-foot container. The maximum gross weight for almost all ISO standard containers is about 30.5 tonnes, and the maximum per the ISO standard is 36 tonnes for all. Thus the smallest (the 20-foot) is the densest at ~940 kg/m^3 using exterior dimensions (which is what the carrier cares about).

 

[Condottiere]

 

[kilemall]

That's for a 40-foot container. The maximum gross weight for almost all ISO standard containers is about 30.5 tonnes, and the maximum per the ISO standard is 36 tonnes for all. Thus the smallest (the 20-foot) is the densest at ~940 kg/m^3 using exterior dimensions (which is what the carrier cares about).

So shipping black holes might be a problem.

 

[coliver988]

So shipping black holes might be a problem.

well, if they can open a wormhole they could be self-shipping!