Sorry all about the mangled table - it started out as fixed width plain
text.

David Jaques-Watson wrote:
 > Has anyone mentioned limiting thrusters by “gravitational drag”
 > (or similar handwave)?

Yes.
So drives have an upper limit of delta-v, for whatever reason.
One question is how well 6G thrusters compared to 1G ones.

 > I always figured that if thrusters are magic-tech, it should be
 > easy enough to “un-magic” them…

There is a very large can of worms in the way.
Getting them to obey conservation of energy has big implications for all
the design rules.

Free kinetic energy is being obtained from somewhere with the rules as
written. This has implications for the rest of the setting unless
perpetual motion machines can 'only' work out in space.

 > Which could be 1% of lightspeed for a 1G drive, up to 6% of
 > lightspeed for a 6G drive.

With the rules as written, distance traveled over a one week trip equals
6AU per G thrust.
At 6G thrust, peak velocity before starting deceleration is very close
to 6% of c.
The required power is on the order of 84MW per kg of vehicle mass,
assuming 100% efficient conversion of input energy to kinetic energy.

Kelly St. Clair wrote:
 > Any form of travel energetic enough to get the PCs from point A
 > to point B in a reasonable amount of time can probably be
 > converted, somehow, into a big enough BOOM to absolutely ruin a lot
 > of people's days.

Agreed, to a point.

We can redefine 'reasonable' to avoid violating conservation of energy
or relativity calculations.

The reduction of delta-v available would increase the rate of in-system
jumps and/or the role of low berths.

It would also change space combat and likely eliminate the need for
gravitic laser focusing, among other handwaves.

Dan/Grimmund wrote:
 > OTOH, ships are multi-million credit investments. Presumably there
 > are some safety interlocks involved in the operating system.

The PC ship is analogous to the small aircraft flown by bush pilots or
tramp freighters/"The African Queen".

So there's some safety features built into the vehicle. In more
populated areas there's traffic control and enforcement of 'road rules'.

The final, most important level of safety is the training of the
operator. Sadly most PCs eschew this.

Rob O'Connor