Vehicle size...

[alqualonde]

What is the size of 1 volume (vl) unit? On page 223 it is stated that 1 vl = 10 liters...
A battledress is 300vl (3kl) and a simple car is 2000 to 5000vl (20 to 50kl). This seems to be too large IMHO.
Normally a battledress is between 200 & 400kg & a car is often below 2 tons (and both have a density superior to 1... They don't float well...)
a single vl should only represent 1 liter. Am I correct?

 

[tjoneslo]

Sigh....

VLs are an abstraction that represents both weight and volume. The problem comes when you try and convert VLs to weight (kg) or volume (kl) or both, as none of the conversion work properly. If you change the conversion so one works properly (VLs to kl, VLs to kg), the other breaks. I've seen (and devised) several conversion that work better for some cases, but not others.

My suggestion is to put it down and back away slowly, as this has the tendency to spontaneously ignite into a flamewar.

 

[veltyen]

Known things. Storage of vehicles on a spaceship requires no extra space at all. Therefore the VL rating of 10 litres per VL is an external rating, a definition of how much space the vehicle will fit into, rather then how much space is in the vehicle.

The TA's redefine a vl to being 5 litres, which is probably a better size for internal space. As tjoneslo points out however VL is an abstraction for both size and mass so that both don't have to be calculated continuously. While it is simpler it is never going to be satisfying for purists. Armour and batteries will be much denser then free cargo space for example.

Battledress at 300 VL means that you can stand 4 fully assembled suits into a dTon crate. Each takes up a space 1.5 x 1 x 2 metres approximately. On the face of it that should be about right, if anything slightly too small for battledress.

A small car at 2000 vl takes 20 cubic metres of storage. 2m high 2m wide 5m long, almost the exact dimensions of most 4WD vehicles. Looking at a small car such as the Mini Cooper which is 3.635 x 1.688 x 1.408. Add a small amount of space as a buffer and you are certainly in the right ballpark. Note that since the units are not directly related (as VL also encompasses some concepts of mass as well as volume, where dTon is purely a volumetric measurement) ballpark is all you are really looking for.

Lastly, its a game, and this is just an abstraction in that game to make things run smoother.

 

[archhealer]

Of course, then it also states that a normal human being is approx. 100vl... If 1 vl = 10 liters, that's 1000 liters! Now, I know i'm not the best spacially, but isn't that one BIG fella?

 

[far-trader]

Actually the way I've come to interpret the 110vl for people in vehicle design is that is the requirement for comfortable safe enclosure INSIDE a vehicle. So it includes the seating, crash protection, doors, space to move around (getting in and out), and all that. Of that just 10vl is the actual person.

So the 10vl "saddle" requirements for vehicles where the person rides EXTERNAL to the vehicle has no real seating, crash protection, doors, or the rest.

The 10vl (being 100L and/or 100kg) fits pretty good as a gross definition to cover all people and carried/worn gear.

Now then, I have arguments with calling "classic" BD a vehicle rather than armor, and being 300vl I see the T20 BD more as a small walker vehicle and thus you should need the Vessel (Ground - Legged Vehicle) feat and not the Armor Proficiency (Battle Dress) feat.

I also believe, among other errata in the vehicles, the Grav Belt is designed wrong and should be much smaller. It should be built using a "saddle" (more of a saddle and harness) and thus require only 10vl for the operator, not the 110vl listed as designed, and the control system would be calculated as a local remote (as was done but not needed since the 110vl for the operator includes controls). The Grav Belt in the book is more of a Grav Sled design, and enclosed ultrasmall vehicle. Possibly an upright egg shape of clear plexisteel with a small seat, or maybe it would be recumbant, in any case that's my pov.

 

[mike wightman]

I agree with Dan that 110vl is closer to the volume for a workstation/cockpit type control station where the occupant is seated.

In battledress the occupant is wearing it like a second skin, and so should use the 10vl control requirement IMHO.

 

[veltyen]

Of course, then it also states that a normal human being is approx. 100vl... If 1 vl = 10 liters, that's 1000 liters! Now, I know i'm not the best spacially, but isn't that one BIG fella?

The space a person fits in rather then the actual size of the person.

1000 litres is only a cubic metre. About the same size as a coffin (which tend to be 2.1 * 0.8 * 0.6 or so).

I suppose you could go smaller if you wanted to remove the ability for the person to get in and out, to move at all or to operate any controls.

Remember that 110 VL is the basic seat + space for the person. At 200 VL you actually have a full supporting seat as well. Bench vs Bucket

The 10vl (being 100L and/or 100kg) fits pretty good as a gross definition to cover all people and carried/worn gear.

I doubt it. Having just measured myself (get your mind out of the gutter

) I would fit in a rectangular prism of 200 * 75 * 50 cm (0.75 cubic metres). If I lost a bit of paunch I might be able to get that last figure down to 40cm or so. As for weight when I was my fittest I weighed well over 150kg (amateur bodybuilding can do that). I must admit that I am at the large end of the human size scale, but there are people both taller and heavier then I.

Depends on what you are looking for in your Marines I guess. Meaty, over 6 foot tall and under 100kg don't really mix that well.

Checking a more normal shaped person (my wife) she would fit into a rectangular prism 170*50*35 (0.3 cubic metres).

Lastly to answer your statement in the affirmative the sport of cramming would fit more with your space dimensions, but I sure as hell wouldn't want to travel that way.

 

[mike wightman]

But people aren't rectangular prisms - rounding all of the corners saves a lot of volume

The human body has an average density similar to water, therefore a form fitting suit of armour like battledress requires a space for the occupant in litres equal to their mass in kg - roughly.

150kg marine would require 15vl inside his battledress.

 

[far-trader]

Originally posted by veltyen:


Remember that 110 VL is the basic seat + space for the person. At 200 VL you actually have a full supporting seat as well. Bench vs Bucket

Excellent visual there. Yes the basic seating is like a tight bucket seat. Roomier seating could be made by doubling the basic vl and cost. The Passenger Couch is actual a different idea entirely. I see it as a bucket seat with ejection/parachute(or grav) capability (hence the higher cost, note the description).

The 10vl (being 100L and/or 100kg) fits pretty good as a gross definition to cover all people and carried/worn gear.

Originally posted by veltyen:

I doubt it. Having just measured myself (get your mind out of the gutter

) I would fit in a rectangular prism of 200 * 75 * 50 cm (0.75 cubic metres). If I lost a bit of paunch I might be able to get that last figure down to 40cm or so. As for weight when I was my fittest I weighed well over 150kg (amateur bodybuilding can do that). I must admit that I am at the large end of the human size scale, but there are people both taller and heavier then I.

As Sigg points out you're smaller than you think

I also think you converted badly or something. 150kg is about 330# so unless you were maybe a heavy framed giant that's a bit over the healthy weight. Except for a bodybuilder or heavy weight class lifter. That's about the top of the class there.

I stick with the assertion that 100L and 100kg (10vl) is about right for most (all was a poor choice above) people. 75kg (165#) is a healthy weight for an average framed male of 180cm (6'). That leaves a little play room for taller and heavier and even bulky clothes.

Originally posted by veltyen:


Depends on what you are looking for in your Marines I guess. Meaty, over 6 foot tall and under 100kg don't really mix that well.

See above. The "average" Marine is likely to be 75kg at 6' tall. What's more the military likes (or did) to put the smaller recruits in the vehicles where size is less of an issue for the person and more of an issue for the vehicle. The "big boys" get to be grunts stuck with the heavy MG.

Anyway, that's my take

 

[veltyen]

Not that much smaller unless I'm in a custom designed form fitting seat, or the position is infinitely adjustable. Battledress early on vs Battledress later on. If there is enough space to move my legs and arms to prevent health problems (what I would want as a minimum) then that space is needed. Deep vein thrombosis, circulatory problems, breathing problems really start adding up.

Looking at the notes on telephone booth cramming and the competition guidelines. Assuming that people competing are selected for size and flexibility (like duh!). A telephone booth is approximately 1m by 1m by 2.2m or 220 VL (as pure volume). The record is 25 people, but that only required that they be at least half in the booth, so from a complete person standpoint it is probably closer to 15 people (or even more probably less then that). This is for short term only and there is no space between people. So that's an answer, and 10VL isn't that far off. Assume 11 complete people and its at 20VL.

I guess thats an answer to how many starving refugees you can cram into a space if you don't mind several dieing.

I also think you converted badly or something. 150kg is about 330# so unless you were maybe a heavy framed giant that's a bit over the healthy weight.

No bad conversion, though I have no idea about the pounds value. I'm 196cm tall (6'5"?) and heavy set. I certainly would be possibly considered as affected by giantism if I was significantly outside the bounds of the rest of my immediate family (the guys are are all over 190cm and medium or heavily built).

As I said, I am an outlier. For some racial groups (polynesians come to mind) that kind of height/weight isn't uncommon. For the imperium (with varying gravities and wildly varying genetics) you may end up with even more problems.

I suppose the Marines can always select based on whether the recruit would fit in the type-1 standard battledress

 

[Tekrat04]

Originally posted by veltyen:
Known things. Storage of vehicles on a spaceship requires no extra space at all. Therefore the VL rating of 10 litres per VL is an external rating, a definition of how much space the vehicle will fit into, rather then how much space is in the vehicle.

You are right that the rule make no alowance for the real volume needed to store a vehicle within another vehicle. It's a major flaw in the rules that dates all the way back to CT.

The ideal that vl is supposed to represent the volume needed to store an object is an assumption on your part. If you read page 235 of THB it clearly states that the vl ratting is the internal volume of the vehicle.

The Chassis determines how large a vehicle is, and is the maximum limit to the size of equipment, personnel and cargo it may carry or have installed within.

Another fact that contradicts your assumption is the design specification of each and every vehicle that make no allowance for the shape of the vehicle. Also note that every officialy publish design 100% of the vl get used in the design.

It has been my observation that the design rules both vehicular and spaceship/starship suffer from a sever lack of common sense. They were not properly thought through and contain a lot of false assumptions. When the readers do not question the laps in common sense in the rules, more false assumptiona ultimatly get made.

In the THB the only direct definition of vl is on page 223.

Volume is given in vl, which represents about 10 liters of volume or 0.01 cubic meters of space.

Weight is define separately.

Weight is in grams (g) or kilogrames (kg).

Unfortunatly there are a few table within the rules that confused the two. This has lead to the assumption on the part of many that 1vl equals 1kg. In TA 3, 6 and 8 the definition of vl was redefined to make this formal. A vl is now 5 liters and 1 kilograme.

Trying to combine volume and mass in a single unit of measurement is bad ideal. There are to many varibles to make it work.

Taking two vehicles at opposite end of the spectrum a tank and a blimp. A blimp needs to mass less than 1kg per cubic meter of air it displaces in order to fly. A tank has a desity of 1200 to 1500 kg per cubic meter of air it displaces. A blimb is a lot bigger than a tank and yet it weigh a lot less. If we use volume to define the vl the blimp would have a big vl than the tank. If we use the mass to define the vl the tank would have the big vl rating. If we compromise all we get is confusion.

The design sequence is suppose to handle all vehicle type without having to create special rules for each type. The units of measure are supposed to represent this. Combining volume and mass as a single unit of measure make this impossible.

 

[SanDragon]

MegaTraveller design rules make allowances for berthing vehicles within vehicles.

Vehicles up to 270kl volume require 150% of their volume to berth.

Small craft of 270kl to 1350kl volume require 130% of their volume to berth.

Starships and spacecraft of 1350kl+ require 110% of their volume to berth.

 

[veltyen]

T20 uses a similar system to the MT one, with the explicit statement that vehicles (of any size) only take up 100%. Spacecraft carried inside other spacecraft do have an assigned extra volume required to carry (which is zero for vessels under 1000 dTon, 10% or 30% in other cases). The distinction is that the additional space required is dependent on both the carried vehicle class and the carrying vehicle class.

 

[SanDragon]

Hmm... Well, if they only need 100%, how do they move out of the parent vehicle, and how are they secured? I had assumed the seeming 'excess' space was for freedom of movement and tie-downs.

 

[far-trader]

I tend to picture it as a kind of rough measure. And so a small craft (under 100tons) will fit within a large craft (over 1000tons) at it's rated size. As well a vehicle (under 10tons) will fit within a small craft at it's rated size (and of course also fit easily within appropriate cargo space on a small craft or larger. Cargo containers are treated as vehicles for size and fit.

It's not the best way, just the easiest that works with the rules.

Rules which I agree seem a bit broken. For example carrying a 95ton Shuttle on a 2000ton ship requires more room than carrying a 100ton Scout/Courier on a 2000ton ship. That's 123.5tons for the Shuttle hanger and 110tons for Scout/Courier hanger. Since when does carrying something smaller require more space?

So for MTU I ignore the size requirement calculations entirely. Anything carried only requires it's size, period. Internally or externally; vehicle, small craft or large craft; no matter the configuration. My caveats are that only vehicles and cargo containers fit in cargo or vehicle holds. Small and large craft hangers will only accomodate the specific type of small or large craft they are designed for; other uses are subject to problems. Externally carried small and large craft grapples will accomodate any craft of that size or smaller. Basically, gotta run

 

[mike wightman]

Since when does carrying something smaller require more space?

When the something smaller requires access to external panels etc. for maintenance?

I've always viewed the 100t ships, with their 20t "bridge" requirement to be fully maintainable from the inside for routine tinkering, but small craft need to have external panels opened etc.

 

[far-trader]

That makes sense, and I could more easily see it if mention of repair or maintenance were made

Or differences in the size of components were there between say a 4ton maneuver drive or power plant in a small craft and the same item in a large craft.

I figure the repair difficulties are the same in both cases. There's room factored into the size of small and large craft for internal access to routine maintenance and emergency repairs can be made. Full maintenance or permanent repairs require external access in both cases.

Vehicles are external access for most work but there's room around it within it's size to do simple stuff.

 

[Tekrat04]

Originally posted by far-trader:
Vehicles are external access for most work but there's room around it within it's size to do simple stuff.

Not true. A vehicle size is actually the volume within its hull including the hull. That means that if you only allocate the size of the vehicle as the size of its hanger there is zero room to work arround it. As a matter of fact there is less then zero room to work arround it.

Lets use the modular cutter as an example of how to design a hanger. A cylinder 6m in diameter, 28.5m long with a hemispereical bow and a reduction in diameter near the rear. Doing the math taking into account all of its diferent shapes you get a volume 50dt.

Right away there is a problem if you only allocated 50dt for the hanger, a strait 6m diameter by 28.5m long cylinder takes up 60dt. And you still do not have any room to work on the out side of the craft.

So lets make the cylinder with a diameter of 7.5m and the lenght 30m. This gives us some room not to dent the cutter nor the mother ship every time the cutter fly in and out. It also give us the space to allocate for the bulkheads and pressure doors, but not for means of pressurising and de-pressurrising the hanger. This cylinder now take up 95dt and you have about the same ammount of space arround the cutter as you have between car in a typical parking lot.

Deck are flat and the cutter is essentially a cylinder lying on its side. This means that we have to factor in the wasted space between the cylinder and the normaly flat floor and ceiling. It's much easier to wlak on a flat surface and in this case the wasted space in the ceiling can be used to store the pumps and pressure containers to pressurise and de-pressurrise the hanger. We now have a box 7.5m wide by 30m long by 7.5m high of a total space of 125dt.

After you factor in the bulkheads you only get about 60cm of manuvering room to work arround the cutter. That is not enough room load and unload the cutter. So lets increase the width and lenght of the hanger by 1.5m. Now the box is 9m wide, 31.5m long and 7.5m high for a total volume of 157.5dt.

So in the end in order to have a reasonable hanger for a modular cutter we need to allocate more than 3 times the volume of the modular cutter.

Shape is a bigger factor in determining the volume required for a sub craft then its size.

If we were to apply the same logic that was used to calculate the volume for the modular cutter to say the CT S/C, the hanger would take up 400dt to 550dt depending on how much room is allocated to arround the ship. With a 95dt shuttle it would be even more due to the wings and tail.

I'll try a work out some gidelines as to how much space should be allocated for different ype of hanger and sub-crafts for a latter post.

 

[far-trader]

No worries on doing all the math on my account

I'm quite aware of it and argued for it many times before. There may be others who will find it interesting though. I've just decided to take a different approach for T20 (since no amount of typing on my part alone is going to make it canon) and chuck some small bits of reality in the interest of playing within the rules.

One of them will not be allowing the players to look at deckplans and say; "Oh, that Cutter hanger is 6m square x however long so while it's 50tons in the design we can still fit 300tons of cargo in there, or redesign it and drop in 75 staterooms."

 

[far-trader]

Originally posted by Tekrat04:
</font><blockquote>quote:</font><hr />Originally posted by far-trader:
Vehicles are external access for most work but there's room around it within it's size to do simple stuff.

Not true. A vehicle size is actually the volume within its hull including the hull. That means that if you only allocate the size of the vehicle as the size of its hanger there is zero room to work arround it. As a matter of fact there is less then zero room to work arround it. </font>[/QUOTE]Well, actually some of it is and can be exernal to the hull/chassis. Parts of the drive train in many cases are. And in fact the actual hull itself is a zero sum item as far as weight and volume go in the rules. So we can toss realism out right at step one

Ah, that's probably where you mean the "less then zero room to work arround it" applies.


Besides I tend to call vehicles 1ton per 1000vl (when in the rules it is 1400vl) when figuring room to park it inside. That gives me lots of room around the vehicle for the odd shape and size issues. And if the players are desperate for the lost volume they can cram soft goods in around it to fill the voids. Same thing with my cargo containers. A 1ton cargo container IMTU is 1000vl and there's a little room around it for squeezing by and tie downs and such.