Vehicle Construction - Size vs Mass

[Aroooo]

[This is more a design question than a rules question...]

When adapting, or even just creating, a vehicle, when determining the size (cost), should you use the vehicle's dimensions or mass as the primary governing factor?

More specific (to help understand the question) example: I'm writing up B5 starships. I have length (and width in a few cases) and mass of the ships. When 'fitting' those numbers into the size chart, sometimes there is a great disparity between dimension and mass, in terms of where the ship fits in the size chart. An Explorer class ship is about 3000 inches long, but only 37 megatons. The size chart would make it either a cost of 175 points - based on length, giving the ship a mass of 3.2 gigatons; or it would be a cost of 145 points - based on mass, giving a length of only 800 inches.

Which should I use?

Aroooo

[Chaosliege]

Originally posted by Aroooo
[This is more a design question than a rules question...]

When adapting, or even just creating, a vehicle, when determining the size (cost), should you use the vehicle's dimensions or mass as the primary governing factor?

More specific (to help understand the question) example: I'm writing up B5 starships. I have length (and width in a few cases) and mass of the ships. When 'fitting' those numbers into the size chart, sometimes there is a great disparity between dimension and mass, in terms of where the ship fits in the size chart. An Explorer class ship is about 3000 inches long, but only 37 megatons. The size chart would make it either a cost of 175 points - based on length, giving the ship a mass of 3.2 gigatons; or it would be a cost of 145 points - based on mass, giving a length of only 800 inches.

Which should I use?

Aroooo

I think you can adjust the length up or the mass down, so it would simply be peronal prefernce.

[Agent Escafarc]

Hey Aroooo,
The term tons(I've also seen it spelled tonnes) when used with ship size is not a unit of weight but a unit of volume (the amount of water displaced by the hull) so a 1000 tons wooden ship is the same size as a 1000 tons metal ship though the dead weight of each is different. It's one of those confusing old English measuring systems. I'm suddenly blank on the exact size in cubic meters but only number in my head this early in the morning is 4 cubic meters but that seems too small

[Monolith]

Sometimes it is impossible to match up stats with items, but keep in mind that the item you are trying to create was designed by a scriptwriter, not a scientist. If a vehicle engineer were designing the Explorer class it might be far lighter or heavier.

But to make things match all you have to do is buy some extra STR and Knockback Resistance for the vehicle; SFX being that it is heavier (works just like Density Increase, only we do not buy DI always on any more).

[Syberdwarf2]

My biggest hang-up (the only one actually), with the Vehicl rules was not a question of Mass. It was a question of Height.
SIZE provides for length and width (Area). It doesn't touch on height (l*w*h). For example; I started working on a writeup for the Andromeda Ascendant. I've figured the L x W, in game terms. But how tall would it be? How many deck levels? etc.

[Agent Escafarc]

Originally posted by Syberdwarf2
My biggest hang-up (the only one actually), with the Vehicl rules was not a question of Mass. It was a question of Height.
SIZE provides for length and width (Area). It doesn't touch on height (l*w*h). For example; I started working on a writeup for the Andromeda Ascendant. I've figured the L x W, in game terms. But how tall would it be? How many deck levels? etc.

Just like Bases each deck's L x W are added together to figure the total area.

[Talon]

TUV answers this question, but I can't remember what the answer is. I think the default is to base the Size stat on the vehicles length (or longest dimension).

[Aroooo]

Originally posted by Agent Escafarc
Hey Aroooo,
The term tons(I've also seen it spelled tonnes) when used with ship size is not a unit of weight but a unit of volume (the amount of water displaced by the hull) so a 1000 tons wooden ship is the same size as a 1000 tons metal ship though the dead weight of each is different. It's one of those confusing old English measuring systems. I'm suddenly blank on the exact size in cubic meters but only number in my head this early in the morning is 4 cubic meters but that seems too small

I understand displacement tons. I got the impression that SH was dealing in mass, not displacement. But then you get into the old habit of trying to fit everything in the volume of a ship

Like others have suggested, I've just gone with length in most cases, and disregarded the mass column where it is 'off' from the 'real world' stats I have. In those few cases where I have length and width, I've used area as the basis for the vehicle's size.

I keep having to remind myself its about the effect, not the 'hard' reality

Aroooo

[Syberdwarf2]

Originally posted by Agent Escafarc
Just like Bases each deck's L x W are added together to figure the total area.

So to use my ealier example;
The Andromeda measures in at Length (657 hexes), Width (164 hexes, and Height (493 hexes). Assuming 1 hex= 6.5 feet, that's 4270.5, 1066, and 3204.5 feet respectively.
With L x W to figure SIZE that's an area of107748 square hexes. Cost for that much area (closest figure in SH expanded vehicle chart is 125000 sq hexes) is 135 points.
Now the juicy part,......
The height is 493 hexes. Assuming that the average deck is 10 feet tall (approx. 1.5 hexes to make it easy), that would give the Andromeda..... 328 decks!....
Okay, so let's whittle that down. Make the average deck height 2 hexes; 246 decks.

Now (only if all decks are the same size), 135 points times 246 decks comes to 33,210 character points. ugh.........

[Chaosliege]

Originally posted by Aroooo

Like others have suggested, I've just gone with length in most cases, and disregarded the mass column where it is 'off' from the 'real world' stats I have. In those few cases where I have length and width, I've used area as the basis for the vehicle's size.
I keep having to remind myself its about the effect, not the 'hard' reality
Aroooo

Another thing to remember when talking about starships. There are no 'real world' stats. It's still just a game.

[Agent Escafarc]

Originally posted by Aroooo
I understand displacement tons. I got the impression that SH was dealing in mass, not displacement. But then you get into the old habit of trying to fit everything in the volume of a ship

Like others have suggested, I've just gone with length in most cases, and disregarded the mass column where it is 'off' from the 'real world' stats I have. In those few cases where I have length and width, I've used area as the basis for the vehicle's size.

I keep having to remind myself its about the effect, not the 'hard' reality

Aroooo

L x W is fine for a vehicle with a single "deck" but for larger ships with multible decks you should add the area of each deck to come up with the vehicle size. HERO does use mass for it's size charts, but most outside sources use displacement for ship/starship descriptions.

[Aroooo]

Originally posted by Agent Escafarc
L x W is fine for a vehicle with a single "deck" but for larger ships with multible decks you should add the area of each deck to come up with the vehicle size. HERO does use mass for it's size charts, but most outside sources use displacement for ship/starship descriptions.

Oh, I agree. When you're designing star ships from scratch, or adapting ships that have a lot of data available (like deck plans), its easy to get l*w*h and number of decks. But when you're working with only partial info, its hard.

Aroooo

[Chaosliege]

With the size you're obviously talking about, I'd buy it as a base. I've never tried anything like that, but there must be a way.

[Agent Escafarc]

Originally posted by Syberdwarf2
So to use my ealier example;
The Andromeda measures in at Length (657 hexes), Width (164 hexes, and Height (493 hexes). Assuming 1 hex= 6.5 feet, that's 4270.5, 1066, and 3204.5 feet respectively.
With L x W to figure SIZE that's an area of107748 square hexes. Cost for that much area (closest figure in SH expanded vehicle chart is 125000 sq hexes) is 135 points.
Now the juicy part,......
The height is 493 hexes. Assuming that the average deck is 10 feet tall (approx. 1.5 hexes to make it easy), that would give the Andromeda..... 328 decks!....
Okay, so let's whittle that down. Make the average deck height 2 hexes; 246 decks.

Now (only if all decks are the same size), 135 points times 246 decks comes to 33,210 character points. ugh.........

From your example your total number of hexes would be 26,506,008 sq hexes which would 195 pts you don't have to by each deck separtly

[Syberdwarf2]

Originally posted by Agent Escafarc
From your example your total number of hexes would be 26,506,008 sq hexes which would 195 pts you don't have to by each deck separtly

Let's see......657 times 164 times....... yup. What you said. Thank you, thank you, thank you.