Re: Tons, tons and more tons - Was: Are Attached files ok?

From: "Charles Taylor" <nerik@?????????.?????.??.uk>
Sent: Tuesday, October 09, 2007 4:54 PM
Subject: Re: [SPELLJAMMER] Tons, tons and more tons - Was: Are Attached 
files ok?


David Shepheard <david_shepheard@???????.com> wrote:

<big snip>

>> Good luck getting this on BtM. I don't want a copy at the moment, as I am
>> very busy and have a big backlog of other stuff I haven't looked at.
>> However, I would like to see this later.
>>
>Well, I'm still working on it ATM - mostly trying to see if the mass
>of data I've accumulated is telling me anything useful!

The only questions I actually think you need to get answered from your 
calculations:

1) How long is the air going to last?
2) How much cargo can you fit onto that type of ship?
3) How much tax is a port liable to charge the ship?

<snip>

>> Do you remember off-hand if the HackJammer ton relates to internal cargo
>> capacity or air envelope size? If HackJammer tons are ship cargo 
>> capacity,
>> they could actually be used *alongside* Spelljammer tons instead of
>> replacing them.
>
>Fortunately, I have the book here: 1 HJ ton is equivalent to a 10' ×
>10' × 10' cube. 1 ton means enough air for 1 man-sized creature for 4
>months.
>
>From calculating the volumes of their ships, at least the easy to
>calculate ones, like the beholder doomship (a cone) does tend to match
>the ships volume assuming 1 ton is a 10' cube.
>
>Beholder Doomship: cone 200' long by 40' diameter or 20' radius.
>Cone volume is pi/3 × height × radius².
>So, thats pi/3 × 200 × 20² = pi/3 × 200 × 400 = pi/3 × 80,000 = pi ×
>26,666 2/3 = 83,775.8 cubic feet.
>
>Divide by 10×10×10 to get volume in HJ tons = 83.78 tones.
>
>Actual listed tonnage = 80 tons - which is close enough.

Very good calculations, but I didn't actually ask for a conversion rule. I 
actually asked if HJ tons were based on cargo capacity. Are you saying that 
80 tons is the cargo capacity of a Beholder Doomship? Or is 80 tons supposed 
to be the entire volume?

>> We could even go the full distance and give three types of tons for every
>> ship:
>>
>> * A "spacial tonnage" that tells us the amount of air in a ship's air
>> envelope and therefore its crew capacity*,
>> * A "cargo tonnage" that tells us the amount of cargo a ship can carry** 
>> and
>> * A "mass tonnage" that tells us the total weight of the ship***
>>
>> * = The relationship between "spacial tonnage" and total ship length, 
>> height
>> and width is why I always ask if people have used mast heights or ram
>> lengths when calculating ship volumes. Maybe I didn't get the importance 
>> of
>> this across before.
>
>Thats one of the reasons I'm posting this spreadsheet - I've included
>estimated (or scaled or diagrams where possible) mast and/or wing
>lengths to produce a set of 'overall' dimensions, as well as the hull
>dimensions.

Thanks for those numbers. They should help a lot of people.

Having looked at this again, I now think that "spacial tons" are the (gross) 
amount of air that the ship displaces - not the displacement *plus* the air 
around the ship. (This means that, depending on the efficiency of the 
design, the "net spacial tons" or useable space would be some number less 
than this.)

As I said to Paul, I think that it might be worth calculating the water 
displacement caused if a spelljamming ship lands in the sea.

And as I also said to Paul, I think that the tons (of mass) would be useful 
to know if a ship was deliberately crashed into a target.

>> Given that we have three meanings for tons, I think it might be worth
>> finding alternative terms that can be used instead of the word ton. Or if 
>> we
>> really don't want to do that, we should at least use the word in
>> co-ordination with a second word that clarifies the sort of ton we are
>> talking about.
>
>I agree about this - but I don't have any good ideas at the moment!

I think a "spacial ton" or a "spacial tonnage" are fairly good for any 
numbers that fit into SJ equations.

If we need to use the sort of tonnage normally used on an ocean (by any sort 
of method) I'd suggest that we have spacefarers call this a "groundling ton" 
and talk about "groundling tonnage". (I think that groundling tonnage is 
probably only relevant if you want to have land based governments that tax 
ships based on their tonnage. If they were groundling governments, they 
wouldn't use "spacial tons".)

(When referring to the cargo capacity, I think that it would be easy to copy 
the way that min and max crew are quoted and list a second tonnage for 
useable cargo space.)

As for mass, maybe we could use a different weight measurement. Maybe we 
could talk about something like a "hundred-weight" instead.

"Pay no attention to the kender behind the curtain."
David "Big Mac" Shepheard
Virtual Eclipse Role Playing Club
http://uk.groups.yahoo.com/group/virtualeclipselrp/links/d20_system_001071937434/Spelljammer_001071430476
http://www32.brinkster.com/virtualeclipse/