far-trader said:
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Presuming that's how gravitics work of course and if you're talking the lifters or the thrusters or a combined maneuver drive package. Just how does it work in your take?
Ah... you know that is a slippery slope my friend, regardless of the local gravity gradient! :wink:
Well, my take from long ago is simple (yeah right) - gravity has a particle/wave duality. The anti-grav part works by neutralizing the gravitons (virtual or otherwise

) acting on a body (but not the other way around - in other words, the gravitic device still has mass and affects other bodies). (This results in a trackable neutrino signature, IMTU.)
Likewise, the gravitons can be generated (or at least a field that acts like such) to simulate gravity and counteract acceleration.
The propulsion part works by acting upon ubiquitous gravity waves that are part of the space-time continuum (queue dramatic overture...). However, it is limited by 'gravitonic harmonics' - while power requirements go up fairly linearly (arg = design rules related to EPs), larger volumes are harder to accelerate. Obviously this was for accounting for the 6G limit and lower spec M-Drives - this, fortunately works for MgT's small craft designs.
As I said, my take is pretty old (early CT days, in fact - haven't thought about it since) - however, in CT, and even MgT that I am aware, there is nothing that would indicate that gravitics wouldn't work underwater. They obviously work in atmo (and plasma, IMTU) - there is nothing stating they don't work in liquid atmo's and underwater as well, to my knowledge. Not to say that currents, like atmo, wouldn't make piloting a challenge. This is supported by the rule mechanics in air. Structurally, I'd limit starships underwater as far as pressure goes (water is a whole lot denser than air). If they are unarmoured, probably less than 100 m. Their 'speed' and acceleration would be drastically reduced. Hypersonic is fine in upper atmo - in lower atmo, the speeder and air/raft set the example, I think. For underwater, a similar limit would seem advisable (like 36 knots or less cruising - maybe only 2-12 for unarmoured ships - max 55-80 for brief stints when armoured [my d6 thinking rears its head

] ).
As to lifters and thrusters - never used them (not part of the original CT that I ever owned). Of the MgT books I have, they aren't part of the rules, as far as I know. However, I
do like bright lights for maneuvering ships, so I resorted to 'optical thermal radiators' for that special Hollywood touch!
P.S. - thanks for the backing on my 'slip' but I must confess to being unaware of the common nomenclature.
A slash combination can be ambiguous and since all star ships are spaceships, I figured the OP might be trying to clarify larger spaceships vs. small craft and not remembering the 'official' terminology. I tried to use 'starship' to be unambiguous.
Mithras was right, and I was wrong in not clarifying I meant my posts when referring to the 'thread' as a whole.