How destructive is this?

[Norade]

If you wanted to hit an FTL target with something like a turbolaser you wouldn’t try to track it. You’d do what infantry are supposed to do when shooting at fast moving aircraft. Predict a point it will pass through, and have all weapons aim at one point and fill it with a barrage. Given a dense enough cone of fire you will score hits, in fact with perfect tracking and weapons accuracy you might have every single shot hit a big target from one salvo. You only get one engagement opportunity, but that’s more or less a given in a sublight vs. FTL matchup, unless the FTL target comes directly at you.

Good answer. If you don't mind, I'll tell you why it's not 100% relevent.

The problem is, that your rifleman isn't trying to fire while he's restrained. The turrets of a star destroyer are restrained by relativity. They might get off a lucky shot, but they will never be able to follow as fast as an FTL projectile can tack across relative bearing.

Your best bet, is like you said, to try and predict the relative motion of the projectile. If your projectile is evading, in a truly random motion, then good luck. Really. Luck will be the decisive factor.

I designed this as a hypothetical defensive weapon for this reason. At long range, the empire can simply hyperspace away or spam the corridor.
This would be a defensive weapon. The ISD has to attack your habitat.
At short range, the warp style FTL has some small advantanges.
1. It's FTL with realtime manuevering. Mostly, the warp field is just used as a combined storage canister/launchtube/booster.
2. The warp field is arguably less affected by gravity wells. (LESS |= NOT) The interdictor might be a decent defence, but I'm starting to doubt the ISD's infallibility to defend against C projectiles too.
3. The warp field is capable of carrying things like this projectile via the mass lightening property. The same property which makes warp kamikaze futile. It's one or the other I'm afraid.

Your projectile is going to be predictable thank to the fact that has to fire towards a known point and can only release from so many exit points and still hit that target. Not to mention that the ISD can track it from beyond Trek's sensor range so they have guns trained on where it will be before Trek even knows they're there.

1. It really isn't that hard to track as it still has a fixed object that it's orbiting and the ISD can fire at it from beyond your sensor range.
2. The ISD isn't infallible versus projectiles as C so long as they know the ISD is coming before it knows what they're up to.
3. The warp field still requires energy to maintain and those energy cost will go up with larger projectiles and, I'm not up on my treknology, but it should also get more costly as the speed increases.

[Soontir C'boath]

Ok, let me go over this and bring a different take to this as I truly should've.

Procedure: You drop the projectile on close flyby, catch it with warp drive, and drop it again and again until it has the energy you need.
Each time it does a flyby, it is going to gain momentum. Actually one star/hole will do if you use warp. With warp technology, you can keep "dragging" and dropping the projectile around the stars until you have the kinetic energy you want.
Once the projectile is up to high relativity speeds, Put it in a warp bubble "treadmill" torpedo. Since warp 1, is lightspeed, this should be no problem for any trek power. The nice thing about warping space, is that the treadmill should be able to orient the projectile in any direction without actually touching it.

So basically, you want the projectile to slingshot out of the binary and then catch it with a warp field (if that's even possible), turn it around and throw it back into the stars to slingshot again.

Think about that for a moment and realize what actually happens. Sounds like you're just playing tennis.
________

Continuing on and let's say this works somehow, you're going to be relying on the tangent velocity as a result of the rotations it goes through and slingshots out in one vector. Keep the bold in mind.

So a warp engine is fitted on a torpedo that must be be near or enclosed the projectile to provide warp 1 and I presume means there are also thrusters on it to change the direction.

BUT, we have never known a vessel go to warp in a direction different than what its real space velocity is. We never see ships entering or exiting warp going the opposite velocity. We do see ships gaining velocity and or maneuvering towards coordinates to go to warp. So it is pure wank and out of your ass to presume they can make objects go to warp in other directions than its real-space velocity. If anything it'll tear the projectile apart considering it's going one way and all of a sudden into another. Though it can perhaps be done in a way in which the projectile can be scooped and warped in a vector towards the system you want to defend. Still doesn't change its vector though.

By the way, considering a treadmill means the person(projectile) and the tread (carrier moving projectile) are going in two different directions. Once the tread mill stops (comes out of warp) and if I'm still running, I'll be running into the dashboard and not out the back.