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Month Index: June, 1996

From:     Leroy Van Camp III <van891@??????.edu>
Date:     Tue, 18 Jun 1996 18:55:19 -0700 (PDT)
Subject:  Re: Air Consumption...

    Note:  The consumption rates come courtesy of Static, who has them
posted on his web peg.  Thanks, Eugene.
    Here in a couple of weeks I will be starting up a Spelljammer campaign
(woohoo!), so I have been going back and reading most of the books.  And,
out of boredom, I decided to take some of the rules and see if they pass a
reality check.
    Of course, this is Spelljammer, and most of the rules are not based on
reality.  Which is one of the reasons I love it so much.  But, one of the
rules that always seemed a little off was the air consumption rules.
According to the Concordance of Arcane Space (COAS), each ton of a ship
provided enough air for one man to breathe for eight months, with the last
four of these being at a lower quality (fouled).  So, if their are 60
people on a 60 ton ship, they will have air for 8 months.  If one person
is on this same ship they will have 480 months of air.
    This seemed a bit high, so I decided to pull out my HP48GX and do
some math.

    Now, each ton of a ship represents 100 cubic yards, which is 2700
cubic feet.  So, a 60 ton ship is 162,000 cubic feet.
    Going from the figures from the COAS, to find out the volume of a
ships air envelop in wildspace simply multiply the ship's volume by 27
(3^3).  Thus our ship would have an air envelope of 4,374,000 cubic feet.
But not _all_ of this spaceis going to hold air.  Things like decks,
weapons and masts take up space.  So we will assume only one half of the
ship can be counted to hold air.  This drops volume to 4,293,000 cubic
    Not all of this air is going to be available for breathing, though.
Some will be consumed in small fires (i.e.  cooking and lamp fires).
Plus, at some point the breathable air will be spread through the rest of
the air, and will be thin enough not to be usable.  So, I will assume
only half of the volume is usable.  Thus the volume of breathable air is
2,146,500 cubic feet.
    According to Static's figures a person uses .5 cf of air while
sleeping, 1.0 during an average non-exertive period, and 1.8 during light
labor, per hour.  So, if a person spends 8 hours per day asleep (4 cf),
eight hours at light labor (14.4 cf), and eight hours doing little but
relaxing or very light work (8 cf), they will consume 26.4 cubic feet of
air.  We will round this up to 30 for convenience.
    (Note that the above are approximations.  There will be times when the
crew will be working harder, but their will also be times when they are
working much less, such as when travelling in a straight line at
spelljamming speeds. )
    So, sixty men on a ship will consume 1,800 cubic feet of air a day, or
54,000 cf a month.  This means a 60 ton ship should carry enough air for a
crew of sixty for 39.75 months.
    So, it looks the SJ figures are off, but on the other side of the

    I am not a mathemtician, so there may be some critical mistakes in my
logic.  Which is why I am posting this to the list.  Any ideas?

	     		  Leroy Van Camp III
  	  owner-mystara-l@??.com         van891@??????.edu
     "You know, not kneeing you in the groin is a constant struggle."

Previous Message: More Realmsspace!Waterdeep cont.
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Month Index: June, 1996

SubjectFromDate (UTC)
Air Consumption...    Leroy Van Camp III    19 Jun 1996 01:55:19
Re: Air Consumption...    phantom@????.????.???.edu    19 Jun 1996 16:42:50
Re: Air Consumption...    Deviant    19 Jun 1996 20:25:10

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