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

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.


> > >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!

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.


> 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/