Traveller Tons vs. Cubic

[RossWinn]

I am working on my Traveller Universe and the idea of using hydrogen displacement tons seems inappropriate. It also seems very inexact and much more difficult to design deck plans for. Has anyone ever converted the Traveller ship construction rules to cubic meters?
What do you see as pros and cons?
Any additional suggestions?

 

[McPerth]

Megatraveller based the volume in kiloliters (that is another way to say cubic meters)...

While the register on it is still on tonnage, the design system uses the kl at 13.5 kl/ton. So, a scout is registered as a 100 dton ship, but all design numbers are done based on its 1350 kl

 

[mike wightman]

That's because the MT folks based their dt definition on the dimensions of the deckplan "cube" rather than the volume of 1000kg of liquid hydrogen.
The 14 cubic metre displacement ton (or 500 cubic feet) is at least based on actual displacement - you can not fit 1000kg of liquid hydrogen in 13.5 kl.

Fire Fusion and Steel for TNE would be my recommendation.

 

[TamsinP]

That's because the MT folks based their dt definition on the dimensions of the deckplan "cube" rather than the volume of 1000kg of liquid hydrogen.
The 14 cubic metre displacement ton (or 500 cubic feet) is at least based on actual displacement - you can not fit 1000kg of liquid hydrogen in 13.5 kl.

Fire Fusion and Steel for TNE would be my recommendation.

Strictly speaking, you can't fit 1000kg of liquid hydrogen in 14 m^3 either (you need 14.114 m^3), even without taking into consideration the volume required for the pressure tank walls, insulation, pipe-runs, etc.

 

[mike wightman]

14 is within wiggle room for 14.11433, 13.5 isn't.

You can use FF&S and then calculate actual fuel tankage by 14.11433.

 

[Baroun Tardis]

Strictly speaking, you can't fit 1000kg of liquid hydrogen in 14 m^3 either (you need 14.114 m^3), even without taking into consideration the volume required for the pressure tank walls, insulation, pipe-runs, etc.

This provides a nice fig leaf for the "deck plans within x%" rule....

 

[mike wightman]

The 500 cubic feet "cube that GT uses is closest - 14.11433 cubic metres is 498.44286 cubic feet.

 

[Timerover51]

As my aged and enfeebled mind still thinks in Imperial units, I just view it as four 5'X5'X5' cubes. That makes things much simpler for using my cargo loading data, which uses either measurement tons or register tons.

 

[mike wightman]

GURPS Traveller uses 5'x5' squares with a 10' ceiling height.

 

[Grav_Moped]

As my aged and enfeebled mind still thinks in Imperial units, I just view it as four 5'X5'X5' cubes. That makes things much simpler for using my cargo loading data, which uses either measurement tons or register tons.

I wouldn't exclude the possibility that this was where it all started. Combat system/maps using 5' squares, rounded to the nearest plausible metric equivalent. Volume of 1000kg of L-H₂ is close enough to 5'x5'x10' for plausibility, and there you have it: a way to measure volume for ship construction. And the numbers for fuel tanks are simple.

Or 10'x10'x10' (as used in other systems) gets you 10 Gross Register Tons... but 10GRT units aren't granular enough, and 1GRT blocks are too small. And neither are easily converted/rounded into metric.

 

[Dragoner]

It is losing all the legacy deck plans that hurts the most.

 

[mike wightman]

Most of them are wrong in some way, no big loss.