Need of an explanation: Tonnage of ships

[mike wightman]

Originally posted by Straybow:
Like I said, they originally used the jargon "displacement" without any evidence of a real technical definition.

They didn't define how the maneuver drive worked until MT, and then they changed it for TNE . Then there are magic inertial compensators and grav plates, magic sensor and weapon systems etc, all of which are not defined until later rulesets (then contradicted in the next ) . At least the displacement ton was defined by 2nd edition CT, where ever it came from.

Even with more detailed design procedures there are still huge gaps in functional roles of mass vs volume.

Only for CT/MT/T20. TNE/T4/GT ship designs all use mass as well as volume to rate final drive performance.

Using the term "displacing [tonnage]" in reference to internal divisions of hull space is even worse. You aren't going to find naval architects (or shipwrights) speaking that way, unless maybe in revising the design and moving one thing to make room for another.

You are in the Traveller Universe

I never saw any official deckplans, but a reverse-engineering explanation might be right on: "We want the ship to be this big on the deckplans, but we've already declared it to be 100 tons."

While I may or may not believe in the "hey, did you notice that 2 deckplan squares are nearly exactly equal to the volume of 1 tonne of liquid hydrogen" coincidence, I know that officially you are allowed 20% leeway on the deckplans and also at least one official deckplan is completely wrong.

Maybe it's a new saying for the TU, "what came first, the dt or the deckplan?"

 

[TheEngineer]

Hi !

Taking a look at my old "The Traveller Book", they expicitly describe displacement tons as the 14 m3 LHyd volume.

Well its only a rule compilation of 1982.
Are there any similar statements in the original LBBs ?

 

[TheEngineer]

Hi !

Taking a look at my old "The Traveller Book", they expicitly describe displacement tons as the 14 m3 LHyd volume.

Well its only a rule compilation of 1982.
Are there any similar statements in the original LBBs ?

 

[TheEngineer]

Hi !

Taking a look at my old "The Traveller Book", they expicitly describe displacement tons as the 14 m3 LHyd volume.

Well its only a rule compilation of 1982.
Are there any similar statements in the original LBBs ?

 

[Straybow]

TheEngr, the original 3 LBBs did not. TTB is a compilation of materials from the basic 3 and several LBB supplements, and the 14 m³ definition was set in a LBB supplement. Somebody said it was Striker.

Sigg, unless TNE/T4/GT have redefined cargo and pricing by mass and volume, at least one gap still exists. In terms of economics and running any campaign other than pure military hack-n-blast, the gap is positioned at the point where a realistic mechanism is most needed.

The only statement so far is that TNE recommends allowing 10-15 tons per dT of cargo. A cross section of shipping (for the last few centuries, at the very least) would average closer to 5 tons per 14 m³. This is also the typical mass:volume ratio for loaded surface ships and land carriers.

Therefore pricing is initially set too low, by a factor of 2-3. The engines and fuel required for a given level of performance consume more space and impose more mass to boot. Resetting that alone would double-to-treble cargo revenues and make standard designs profitable.

 

[mike wightman]

Straybow mused:

Somebody said it was Striker.

It may have appeared in an early Journal . It was certainly in use for 1st edition High Guard 1979.

 

[mike wightman]

Straybow mused:

Somebody said it was Striker.

It may have appeared in an early Journal . It was certainly in use for 1st edition High Guard 1979.

 

[mike wightman]

Straybow mused:

Somebody said it was Striker.

It may have appeared in an early Journal . It was certainly in use for 1st edition High Guard 1979.

 

[TheDS]

In RL, ships are described in terms of mass, because that is the most important factor. You can have ultra-light yet thick hulls, and spars going everywhere, so long as you don't exceed a certain mass. Mass determines how fast you can go and how hard you'll hit something if you don't stop, and also how much fuel you use to get where you're going.

However, once you have something that cares about VOLUME instead of mass, then you have to know what that is, and rate to it. That something is the Jump drive. It doesn't care about mass (within reasonable limits, I'm sure) to determine how much fuel it will take to travel. It cares about volume. Pull in those spars, save fuel. Thin up the hull and make it tougher and denser, save lots of fuel.

The usage becomes so important that it bleeds over to places where it doesn't necessarily belong. Non-starships still care about mass, but most of them have such a low need for endurance that it doesn't matter.

But mass is still important, because it still regulates how fast your ship can travel out of jump. So in keeping with TNE's move away from the "pull a value out of your a$$" method and toward the real physics method, the design sequence takes your ship's mass into account. Ships with extremely thick hulls (which are really dense too, btw) are going to get an appropriate penalty on their speed and endurance. It's good to know that you're not going to face some totally unrealistic (yet not entirely consistent) behemoth, and also serves to stem the flow of munchkined designs. (No more moving neutronium hulls with the same engines required to move paper hulls.)

 

[TheDS]

In RL, ships are described in terms of mass, because that is the most important factor. You can have ultra-light yet thick hulls, and spars going everywhere, so long as you don't exceed a certain mass. Mass determines how fast you can go and how hard you'll hit something if you don't stop, and also how much fuel you use to get where you're going.

However, once you have something that cares about VOLUME instead of mass, then you have to know what that is, and rate to it. That something is the Jump drive. It doesn't care about mass (within reasonable limits, I'm sure) to determine how much fuel it will take to travel. It cares about volume. Pull in those spars, save fuel. Thin up the hull and make it tougher and denser, save lots of fuel.

The usage becomes so important that it bleeds over to places where it doesn't necessarily belong. Non-starships still care about mass, but most of them have such a low need for endurance that it doesn't matter.

But mass is still important, because it still regulates how fast your ship can travel out of jump. So in keeping with TNE's move away from the "pull a value out of your a$$" method and toward the real physics method, the design sequence takes your ship's mass into account. Ships with extremely thick hulls (which are really dense too, btw) are going to get an appropriate penalty on their speed and endurance. It's good to know that you're not going to face some totally unrealistic (yet not entirely consistent) behemoth, and also serves to stem the flow of munchkined designs. (No more moving neutronium hulls with the same engines required to move paper hulls.)

 

[TheDS]

In RL, ships are described in terms of mass, because that is the most important factor. You can have ultra-light yet thick hulls, and spars going everywhere, so long as you don't exceed a certain mass. Mass determines how fast you can go and how hard you'll hit something if you don't stop, and also how much fuel you use to get where you're going.

However, once you have something that cares about VOLUME instead of mass, then you have to know what that is, and rate to it. That something is the Jump drive. It doesn't care about mass (within reasonable limits, I'm sure) to determine how much fuel it will take to travel. It cares about volume. Pull in those spars, save fuel. Thin up the hull and make it tougher and denser, save lots of fuel.

The usage becomes so important that it bleeds over to places where it doesn't necessarily belong. Non-starships still care about mass, but most of them have such a low need for endurance that it doesn't matter.

But mass is still important, because it still regulates how fast your ship can travel out of jump. So in keeping with TNE's move away from the "pull a value out of your a$$" method and toward the real physics method, the design sequence takes your ship's mass into account. Ships with extremely thick hulls (which are really dense too, btw) are going to get an appropriate penalty on their speed and endurance. It's good to know that you're not going to face some totally unrealistic (yet not entirely consistent) behemoth, and also serves to stem the flow of munchkined designs. (No more moving neutronium hulls with the same engines required to move paper hulls.)