I think that there has to be some common sense. Is the whole planet a vehicle that can be slowed or grabbed? Where does it end?
I like the idea that for something big, you're only attacking one piece of it. Just like, if you attack a rock you're not attacking the whole planet. Likewise, maybe you can slow the ship's rudder (which makes turning more difficult), but even slowing a piece of the keel (if you can target it) or a piece of one of the sails isn't going to do anything.
I like the idea that for something big, you're only attacking one piece of it. Just like, if you attack a rock you're not attacking the whole planet. Likewise, maybe you can slow the ship's rudder (which makes turning more difficult), but even slowing a piece of the keel (if you can target it) or a piece of one of the sails isn't going to do anything.