Displacement Ton

[Xoph]

What is a Displacement Ton? After some research on the boards and an articles on Freelance Traveller (Included both answers as did most sources) I came up with two different yet equally strange answers:

1) Displacement Ton = 14 cubic meters

• a) cubic meter = 1 meter by 1 meter by 1 meter
  b) Displacement Ton = 14 meter by 14 meter by 14 meter

(example) using this version a 4 ton stateroom is 14 meters tall 28 meters by 28 meters.

2) Displacement Ton = 3 meter by 3 meter by 3 meter

• a) Displacement Ton = 2 map tiles
  b) map tiles = 1.5 meter by 1.5 meter by 1.5 meter

(example) using this version a 4 ton state room is about 5 squares to get a reasonable ceiling of 2.5 meters, but this needs to include the hallway to get to the stateroom. making a stateroom 3 meters by 3 meters by 2.5 meters plus 1.5 meters by 1.5 meters by 2.5 meters of hall. that is a pretty small room especially if it includes a refresher and a bed and desk and chair.

So which is right? Is there another option?

 

[TrippyHippy]

Displacement Ton, I think, is an old naval term refering to the volume of seawater set to the equivalent mass.

In Traveller, however, they've established the term as representing liquid hydrogen instead (where a d-ton is equivalent to 14 cubic meters).

 

[EDG]

What is a Displacement Ton? After some research on the boards and an articles on Freelance Traveller (Included both answers as did most sources) I came up with two different yet equally strange answers:

1) Displacement Ton = 14 cubic meters

• a) cubic meter = 1 meter by 1 meter by 1 meter
  b) Displacement Ton = 14 meter by 14 meter by 14 meter

(example) using this version a 4 ton stateroom is 14 meters tall 28 meters by 28 meters.

Nope.

14 cubic metres means "a volume of space that has a total volume of 14 cubic metres", not 14x14x14 metres (I suppose it'd be better to call it "14 metres cubed"). So to find out the real volume of a displacement ton, you can take the cube root of 14 and you get a cubical volume that's about 2.4 x 2.4 x 2.4 metres.

Or, interesting enough, that is equivalent to a spherical volume that has a radius of about 1.5 metres (volume of a sphere is 4/3*pi*r³, so the volume of a 1.5m radius sphere is 14.14 m³).

 

[rust]

Oops, there must have been a misunderstanding. :shock:

Fourteen cubic meters are fourteen times one cubic meter, for example a
volume of 14 m x 1 m x 1 m, or 7 m x 2 m x 1 m, or 3.5 m x 2 m x 2 m.

A volume of 14 m x 14 m x 14 m would be 2,744 cubic meters.

Edit.: Ah, and again EDG did draw faster ... :lol:

 

[Xoph]

Thanks rust and EDG!

Okay so what are the the dimensions of a 4 dton stateroom then?

My figuring sets the ceiling at 3 meters with deck width I suppose.

Making a stateroom 3x6x3 meters and a bit or a total of 8 squares with two squares high.

Does this sound right?

 

[EDG]

A 4 dt room is 56 cubic metres (14 x 4). That's a cube that's just over 3.8 metres on each side, or if you think of each dt as a sphere of 3m diameter (14 m³) then that's a room that contains 2x1x1 spheres, so 6x3x3 metres (and a bit left over).

So yes, you're right.

 

[rust]

A 4dt stateroom would have 56 cubic meters, and with a height of 3 m
this would leave a value of 18,66 to be divided into the other dimensions,
for example 6 m x 3.11 m.

So, yep, 3 m x 6 m x 3 m fits very well.

Edit.: Ah, and he did beat me again ... :lol:

 

[Xoph]

So then here is the pain in my ass. I just designed a ship using dton squares; meaning that every square according to EDG is 2.4x2.4x2.43055 repeater making dimensions little strange.

How do you guys deal with deck width? or hull thickness?

I hope this stuff is in High guard.

 

[rust]

I use the "traditional" Traveller system of two squares of 1.5 m x 1.5 m
each, and assume a height of 3.11 m including the deck, for 1 dton.

In my setting the deck with the various cables and pipes and whatever in
it is about 61 cm high / thick, which leaves a room height of 2.5 meters.

If you use 1 square = 1 dton, things indeed become a little more difficult.
You could decide to make each square 2.5 m x 2.5 m, which would leave
you 2.24 m for the height. If you assume a deck thickness of 24 cm, still
a plausible value I think, you would arrive at a room height of 2 meters.

 

[Xoph]

Yes I would like to use the traditional squares too. I guess It will take a bit to do the conversion. Arg... oh well.

 

[Ishmael]

I use the idea that 1dton=13.5m^3
When using 1.5m squares on maps, and assuming 3m high, 2 squares is one dton.
1.5m is also pretty close to 5ft so its easier to guesstimate english measurements too.

my 4 dton stateroom is around 6 squares 3mx4.5m or 10ftx15ft and the remaining 2 squares allocated for passageways/commons/lockers/etc.

I also figure about .5 m deck thickness ( enough room for conduits/ducts/pipes/stuff ) so ceiling heights fall in just under 8 1/2 feet.

the difference from the 14m^3 per dton is close enough and mapping always gives wiggle-room....especially in odd shaped hulls and sloping/low ceilings

 

[hdan]

What Ishmael said - two map squares per ton. For staterooms, the whole inhabited area just needs to add up to the right number.

For example, 10 4-ton staterooms would take up 80 squares, which each actual room maybe getting 6 squares and the remaining 20 squares going into the common area and hallway.

 

[GypsyComet]

There are two "traditional" methods used by Traveller. Which you decide to use is up to you, as long as there is a scale on the drawing.

1.5m grid with ~3m deck spacing. This maps to two squares representing a displacement ton.

2m grid with 3.5m deck spacing. This maps to one square representing a displacement ton.

Which to use? The 1.5m grid is very close to 5ft, which is a measurement us antiquated Imperial measures types are comfortable with. The 2m grid, on the other hand, can be mentally converted for movement and weapons ranges a little more easily.

Note that you don't have to be slavish about staying on the grid lines for starship walls, etc, and the entire stateroom volume is not necessarily *in* the stateroom. That volume can also include hallways, lounges, kitchen facilities, etc.

 

[StephenT]

As a comparison, I had a look at acommodation on cruise ships.

Assuming one grid square is 1.5m or 5 feet per side, which is 2.25m² or 25 square feet:

• A deluxe passenger cabin on the QE2 is about 200 square feet, which means eight gridsquares.
  A standard outside cabin is 150 feet, which is six grid squares.
  An inside stateroom is 100 square feet, or four grid squares. It has bunk beds.

And by contrast, US Navy regulations state that the recommended size for an officer's stateroom in a large ship is 50 square feet, or two grid squares. The ship's captain gets 90 square feet (almost 4 grid squares). Ordinary crewmen are crammed into bunkbeds stacked three high with just enough room to squeeze past them - and if they're unlucky, there's only one bed per two sailors so they have to share...

 

[captainjack23]

As a comparison, I had a look at acommodation on cruise ships.

Assuming one grid square is 1.5m or 5 feet per side, which is 2.25m² or 25 square feet:

• A deluxe passenger cabin on the QE2 is about 200 square feet, which means eight gridsquares.
  A standard outside cabin is 150 feet, which is six grid squares.
  An inside stateroom is 100 square feet, or four grid squares. It has bunk beds.

And by contrast, US Navy regulations state that the recommended size for an officer's stateroom in a large ship is 50 square feet, or two grid squares. The ship's captain gets 90 square feet (almost 4 grid squares). Ordinary crewmen are crammed into bunkbeds stacked three high with just enough room to squeeze past them - and if they're unlucky, there's only one bed per two sailors so they have to share...

Good stuff ! There was, IIRC, a fairly reference heavy thread on this during the playtest - I'd search and link but I'm needed at the dinner table...

 

[GypsyComet]

The last hotel room I was in (nominal capacity four people) was just about 6 displacement tons by eyeball.

It can be eye opening to map your own house in 5ft grid. Also recommended is to find a quiet park or street and pace out the exterior dimensions of a Scout/Courier. If possible, map the Scout's interior (main deck) and make sure a car is in the spot for the air/raft garage.

 

[EDG]

It can be eye opening to map your own house in 5ft grid. Also recommended is to find a quiet park or street and pace out the exterior dimensions of a Scout/Courier. If possible, map the Scout's interior (main deck) and make sure a car is in the spot for the air/raft garage.

It's funny because I was literally just thinking about that myself - I was looking around my apartment thinking "how many 3m diameter spheres can I fit in here", and it's really "eye-opening" as you say . My own bedroom is 3 x 3.5 x 2.6 m, which is almost exactly 2 displacement tons. A 4 dt stateroom would be huge!

 

[Vile]

I can't remember what the TMB says, now, but in CT those 4 dtons also went to contribute to corridors and other common spaces. So, your actual stateroom might only be 6 square (as shown on most old deckplans) or even 4 squares. You can easily fit everything a stateroom needs into 4 squares, which actually allows you to design the rest of the deckplan without going over the +10% tonnage fudge factor.

 

[simonh]

I think it's been said, but it's worth repeating that the 'stateroom' space doesn't have to all be in the room itself. If you look at most deck plans, the room itself tends to be either 4 or 6 squares in size, leaving another 2 or 4 squares for corridors and shared recreation spaces. Note that if you have two 6 square rooms opposite each other, the corridor between them takes up either 2 or 3 squares depending on orientation, leaving 1 or 2 squares left for shared space. That's a useful rule of thumb when working out deck plans.

Simon Hibbs

 

[ninthcouncil]

Traditionally, Traveller doesn't assign any space to life support machinery, so that should really come out of stateroom volume too. But then traditionally it hasn't shown up on ship plans either, and I've tended to handwave it into the tween-decks.