@Blackpatriot & MajorD: The shuttle then would have to take it's warp engines offline if it were to park itself inside it's counterparts warp field, that way, there shouldnt be two warp fields trying to work on two seperate objects.
That's not true, we've seen ships align warp fields before, like Enterprise and Columbia, they aligned their warp fields to allow Columbia to transfer Trip, then they used Columbia's engines to sustain Enterprise whilst Trip fixed the warp core. I'm not sure why it was necessary for Columbia to sustain them though, shutting down the warp core would have simply cut power to the warp engines, and the ship should have just slowed down to impulse. I suppose there could have been a design flaw in the NX class, since it wasn't actually designed to go at the speeds that Enterprise was, so perhaps the nacelles wouldn't have been able to handle the sudden loss of power, and they couldn't ramp it down because of the Klingon virus.
They need to have their engines going in the first place to maintain the warp field that is being sustained, unless they are running on pre-charged warp engines. Ships in Trek also have absurdly long ranged sensors. In an episode of DS9 a runabout detected another ship 20 light years away, I don't think it was at warp either.
I prefer to interpret that as they were able to detect the warp signature of the ship from that distance, not as the actual sensors could scan that far. That lends some evidence to the idea that long range sensors are passive, with large restrictions on both the range and accuracy of active sensors, not to mention the fact that it'd increase the sensor profile of the scanning ship. The best analogy would be submarines, if they use their active sonar then they can detect other ships within a certain range, however the ping from their sonar can be detected far beyond the range that they can pick up the echos. But they can also pickup loud engine noise from great distances, that's why they have to travel relatively slowly to remain undetected. In the same vein if the warp engines were barely being used, such as when maintaining a warp field, then that would give the ship a very small sensor profile, which would blend into the background radiation of the universe at a distance. If the ship had to change direction though I would assume that doing so would increase their warp output, which in turn makes them more detectable.
The problem is to compensate for the changes in field structure I would expect you would need to be able to create that strength of field in the first place. If that's the way ships turn, by creating differently balanced fields. But, perhaps it's a matter of using normal thrusters and the field just being reoriented with the ship. If that's the case, then the warp sustaining shuttle would not be able to turn a sustained warp field, because it is not generating the field continuously, only keeping it going. If it turned, then it might only fly sideways at warp. That could even be how the Enterprise-D pulled off the on a dime turn without being mentioned to drop from warp. It could have turned its warp engines to a sustainer mode, turned on its axis, then re-engaged the engines
Well there really isn't any evidence one way or the other, though I do recall impulse engines being off at warp, but that might have been my imagination, or an FX error. If I had to guess I'd say that the warp engines modify the geometry of the field momentarily, enough to change the heading of the ship, and then return the field to normal once the maneuver is complete. I'd also say that the warp coils (the coils are in the nacelles, and they're huge. I'm looking at you Enterprise...) in the nacelles are physically oriented so as to produce a field in a certain way to get the best economy from the engines, and that the turning rate of the ship is limited by the energy that can be pushed through the coils, as well as the ability of the structural integrity field to keep the nacelles on the hull, can't be easy to balance the stresses of rotating a starship at several hundred times the speed of light.
Following that line of reasoning I've actually had an idea that I've been working on for a while for a class of ship that would incorporate both variable geometry nacelles (not the pylons, the actual nacelles, including the coils) along with a sort of stealth armor, designed to absorb energy emissions, much like the acoustic paint and rubber tiles on submarines. I will admit that the design has more than a passing similarity to the Normandy from Mass Effect, with good reason, that ship is awesome. The basic idea is that the ship is coated in the armor, and as long as there's a charge running through it it will absorb radiation, preventing the ship from giving away it's position. It would also fool active sensors, though I'd assume that if the scanning ship got too close then they'd be able to overwhelm the armor with high intensity scans. The variable geometry nacelles would allow the ship to have a stealthy warp profile but a limited top speed and fuel economy in the closed position but in the open position they would allow for a very high warp speed, and good economy, at the expense of making the ship as visible as any other.
Is it just me or do the posts in tech related subjects just get longer and longer...