ah, so your seeing the ship as the projectile.
one major problem. the 'coils' would have the same effect working on them as the ship. remember the law 'for ever action there is an equal and opposite reaction' that means if the ship is accelerated along a coil, the coil will will accelerate in the opposite direction. the change in the speed which the two move are inversely proportional to the difference in their weight. if the "coil" is 4 times heavier, it will move away from the start poing 1/5 as much as the ship does. at the other end the recieving coil will have to assorb the speed, which will cause it to accelerate along the path. there would be no saving of applied thrust, only transfering it from the ship to coils.
also there is friction in space, mostly from the photons but also from the very weak solar wind. watch a vidio of a comet some time. its tail is caused by photonic pressure.
