ok first dont use a draw event, create an actual object for the thrust thingy.
create it in the ship create event and call it something like
dude = instance_create (self.x,self.y,obj_thruster)
then in the END STEP event of the ship put
Code:
if instance_exists (dude)
{
if dude.x != self.x{dude.x = self.x}
if dude.y != self.y{dude.y = self.y}
}
the reason you put it in the end event of the ship is that if you have the thruster trying to follow in step wit the ship a lag will happen, putting it in the end step of the ship means the ship will move, the ship will move the thruster and then the image will be displayed, the difference is move ship, show, move thruster versus move ship, move thruster, show
and finally when the ship is destroyed you have one line of code before that says
with(dude){instance_destroy()}
that way only the dude you created for the ship when it was created will be the only dude thats destroyed when the ship goes down.
have a great day dude