Since even a Tigresses mass does not collapse its own bubble, there is no reason that a 500k+ jump gate (a starship actually) would effect the jump. A ship of even 1M dtons is infinitely small when compared even to a small moon. Even if a micro, micro gravity field were created, I am sure this can be calculated and compensated for with a core/10 computer.
Because it is (kind of by definition) inside the jump bubble. The jump gate isn't, or it'd go with it.
Drop tanks make a jump more difficult because they are mounted outside if the ship that is actually making the jump and can distort the warp bubble.
Not at the point it jumps, they aren't. They are forcibly ejected during the jump process and are lying around in space nearby, not actually inside. High Guard:
Jumping is a delicate procedure, which is greatly complicated by having big empty fuel tanks flying around in close proximity to the jump bubble.
The mass of a jump gate is lower than a planet but it's also a hell of a lot closer; the 100 diameters rule takes into account the size of the object and I'd imagine it's going to be difficult to pass through a gate without being within 100D of it.
The actual density is going to be more than a small moon - granted it's got hollow spaces but it's also going to have a shedload of exotic alloys that make iron look like cotton wool. Even the density of contemporary steels is about 40% more than the average density of the planet earth.
Admittedly, as you note, a mega-dton ship is infinitesimally small compared to a planet, and as such its 100D volume is also infinitesimally small, but you are specifically goint into that region in order to use it.
Not saying it's not possible, but it will be harder than normal and hence I suggested a negative DM on whatever autosystems run the jump calculation to take that into account. If you want to stuff the computer running the calculations full of sufficient expert programmes to counteract this, fine (they're your credits).
One other point, you'd probably want to add some arbitrary percentage to the size of the jump drive.
The jump bubble isn't something you can just 'fly into' or else when drop tanks are caught be the expanding bubble, they'd be brought with you into jumpspace rather than being destroyed. Equally, Grandfather's ship flying into a jump bubble to join yours is one of the "
what teh krunk?" moments in Secrets of the Ancients.
There's nothing wrong in theory with creating the jump bubble around the target ship; we haven't seen a jump drive that does that previously but equally have seen nothing that says that's impossible.
However, I'd postulate a bigger, more convoluted jump drive required to create a bubble not centred on the drive for the same reason most unidrectional projectors - lasers, directional antennae, heat pumps etc, are more complex than the equivalent omnidirectional equivalent - light bulb, wire, radiator.
My thoughts are that if you implement jump on non jump capable ships < 1000 dTons, then you should be wary of creating a game imbalance caused by being able to fling (generally) more powerful SDB's around your sector. Also, if you jump SDB's to systems that don't have a gate, then they effectively become stranded unless you get a carrier capable of picking them up to them, etc. I would think these gates, would effectively change the makeup of a lot of the smaller subsector fleets, and would become major assets to those that owned them, or wanted them.
They would indeed, but as noted, it's a one-way trip and (unlike a battle rider carrier) a squadron doesn't all arrive together, so it has its disadvantages as well.
