Re: FT cargo/aux ships.

On Thu, 19 Aug 1999, Ryan M Gill wrote:

> On Thu, 19 Aug 1999, Tom Anderson wrote:
> 
> > otoh, since the cargo bays aren't tied to the drive assembly, you
don't
> > have your expensive components (the ones in the tug) sitting in port
for a
> > day or two while the ship is loaded - if trips between ports are on
the
> > order of weeks and layovers are on the order of days, you have 10-15
% of
> 
> Why not? If you are transporting bulk cargo, you're going to have a
big 
> volume freighter. Use sublight lighters to transport the material
planet 
> side. To get it up to orbit, you use a rail gun on low grav worlds. 

on first reading this paragraph, i thought you were disagreeing with
mne;
now i think it's support. someone agreeing with me? impossible! :)

> What about the palettized container ship concept. Small orbital
shuttles 
> (ala the trucks) transport the cargo up to the ship, they are attached

> (internal or external) to the freighter. 

it would be more mass-efficient to use the shuttles to carry containers
which are loaded on the freighter, rather than attaching entire
shuttles.
otoh, it is less time-efficient. this is the crux of the difference
between hold-type and tug-type frighters. otgh, if the containers are
huge
(a few thousand tonnes each), they would be very quick to load and
unload.

> I don't know that a Tug would be the same as a cargo freighter. In the

> case of the tug, its extending its drive field around a separate
craft. A 
> freighter would already have the drive field emmitters placed at 
> strategic locations around the ship to warp the space around it and
jump 
> to light. 

it's true that the freighter has a more deterministic load, and one that
can be better balanced around the ship:

#=# bits of ship
* carried stuff

freighter:

 ******
#======#
 ******

tug:

#=======#
  ****
  ****
  ****

> Whether it had entirely internal cargo holds or attachment points, I 
> don't see why it would count as a tug. Its always transporting the
same 
> volume of objects. 

that's quite true - a tug's ftl drive is less efficient than a standard
ftl drive. in this case, you could probably say that the lighters were
effectively part of the ship when carried (provided they were quite
small), and claim standard ftl efficiency. there is still the cost of
the
lighters' systems to deal with, though.

> This has me thinking about my idea for PT boats and an associated
tender 
> for them. Essentially a ship just like a Landing Ship Tank that trucks

> around LCMs and LCIs (or what ever) for the actual interface to the 
> surface. The PT boats would stay in system and get shuttled about to 
> other systems with the tender. They'd get transported in the bays of 
> the tender and be size 6-8 with no FTL drive. But the tender wouldn't
have 
> to be costed out like a tug (just like the auxillary ships that move
the 
> interface craft around). Still it'd be merchant like and not a good 
> combatant. 

i understand that this is essentially how the IF operate.

> There benifit would be small, handy craft hardly worth A Batt shots at

> that moved pretty fast, but not as fast as fighters. The'd have pds, a

> torpedo and a 8 thrust engine to make maneuver easy. The perfect thing
to 
> operate in systems that were in contention or that were transfer
points for 
> merchant ships. The tender wouldn't necessarily have to be insystem
all 
> the time, just when they needed to make a strategic move. 

like star destroyers in star wars (at least, the computer games).

tom