..::Your code. Feel happy::..
//at start of script, define a vector "tempvec"
Code:
vec_set(camera.pan,vector(hovercraft.pan-90,hovercraft.tilt,hovercraft.roll) );
vec_set(tempvec,vector(-150,0,75));
vec_rotate(tempvec,camera.pan );
vec_add(tempvec,hovercraft.x);
vec_set(camera.x,tempvec);