Gravity in space?!?! Umm... as with all things moving in space, something must either push it or pull it. Missles and torpedos would act like those today in Earth's atmosphere, a small rocket propells them thru the air, the little fins on the back of the missle control its direction. In space, instead of fins, the nozzle of the small rocket engine moves up/down/ left/right to control direction. Bombs would also have small rockets or thrusters to move them thru space. Zero G is zero G. The only time you have gravity in space is either artificially produced or a rotating platform at such a rate that it produces gravity on its surface in the direction of rotation, and on the opposite ends of the rotation. Dropping bombs in space, no such thing. Fireing bombs in space, that is possible, like fireing a rocket in space.
A very strange way of delivering ordinance to a target. The enemy could in effect deflect that by producing opposite gravitational forces focused and aimed at the torp, in effect 'push' it away or off course. I think that "Skipper" torp the cats had in WCIII would have better chance, since it cloaks often. But then again, if you have cloak sensors, thats useless, like putting cloaks on ships, then you can see them! What would be better is a weapon that actually "shifts" in and out of space time so that not only would it dissappear, but be undetectable unless you shifted to the same space time as the torp did. Program that puppy to shift out of current space time, fly to target, then re-appear 50 or so clicks away from target! BOOM!
They had anti personnel mines in an episode of Deep Space Nine, The Siege of AR-58 i think. The mines would hover in subspace and would randomly reappear in normal space and if someone was near, kablooey.
I would bet that idea for that episode came from the game ST Final Unity. That "unity device" would shift out of space time and not return for 450,000 "balchacks", the Chodak measurement of time. If a weapon such as a torpedo could do that, it would be a very difficult task to protect or escort large slow moving ships.