Re: Ship sizes - was: staircases are major headaches!

On Fri, Jun 02, 2006 at 04:30:18PM +0100, Dreamer wrote:
> In <URL:news:local.spelljam> on Fri 02 Jun, Johannes Werner wrote:
> > On Thu, Jun 01, 2006 at 12:58:49PM +0100, David Shepheard wrote:
> > > >From: Johannes Werner <joe@???-?????.de>
> [snip]
> 
> > > >> (BTW: I'm not sure if the spelljamming helm works on weight or mass, but
> > > >> for arguments sake, I'll say it works on mass and you don't drop like a
> > > >> stone when your ships weight suddenly jumps above 50 tons.)
> 
> SJ Helms work on volume, but the structure of the ship still
> needs to be able to handle its own weight or mass.  It seems
> likely that a Helm supports a ship at least as well as floating
> it in water does.

Ah, that was what I remembered. The considerations about the structure
are the reason why of every ton of ship only a certain fraction is
available as storage space.

> > > >Would make sense to me...
> > > 
> > > Actually, after doing a tiny bit of Googling to look for nautical terms it 
> > > looks like ships tons could be a measure of volume rather than a measure of 
> > > weight or mass:
> > > http://en.wikipedia.org/wiki/Ton#Units_of_volume
> > > "One freight ton or measurement ton is equal to...40 cubic feet."
> > > 
> > > I say "could" because Wikipedia also has a displacement ton and a 
> > > deadweight ton:
> > > http://en.wikipedia.org/wiki/Ton#Units_of_mass
> > > 
> > > "A displacement ton is...the mass of 35 cubic feet of water." and a 
> > > deadweight ton is the same as a long ton (2240 pounds). Either of these 
> > > types of tons may have been used by the original designers of Spelljammer. 
> > > (This might cause a mathmatical error to anyone trying to convert sailing 
> > > ships from other RPG products!)
> > 
> > Hm, wasn't there something in the core rules that one ton was equal to
> > (some amount) of (I don't remember)?
> 
> One spacial ton is 100 cubic yards or 2700 cubic feet - a lot
> bigger than a displacement ton as used in nautical settings.  It
> is very definitely a messure of volume, not mass or weight.
> 
> It took me _ages_ to get this straight for myself!

Thanks for reminding me!
Is this documented on BtM or the temporary conversion page? It would
certainly help a lot...

> This makes the one ton Flitter a vaguelly credible craft, which
> if it was a cube would be 14 feet on a side.  Seeing as it has to
> be at least 25 feet long to have a gravity plane, it could be
> about 25'x10'x10'.
> 
> 
> > But since this discussion has been
> > going on for a while (and keeps popping up in connection with ship
> > sizes), I don't really know. For a conversion of ships, I usually just
> > take a ship from the rulebooks that has more or less the same properties
> > and then just change it around a bit. This _can_ be a quick process (but
> > does not have to).
> 
> That was how most traditional ship design was done - take
> something that works and change it around a bit to try and
> improve the things you want.  I understand that proper
> hydrodynamics (astrodynamics?) was only really settled in the
> early to mid 20thC.  Dragging models through a tank of water was
> quite popular.

Well, trial and error does work...

> > To accelerate discussions, one of my old gaming
> > groups had a sand glass (1 minute?) that would be turned around by the
> > person being sick of the discussions. Time stops -> discussion stop.
> > Yes, it _did_ apply to players _and_ GM...
> [snip]
> 
> Fun! [grin]
> 
> -- 
> Dreamer
> dreamer@??????.?????.??.uk
> http://www.romsys.demon.co.uk/
> 
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