Maybe its just my impression but I feel Imperial Clipper power plant is harder to hit than other big ship PP. Makes me not bothering targeting the PP at all since most times its hull pops earlier.
Ditto, but I still target it. Most of the time I get the pwr. plant down to 0 before the hull reaches 10. The soft underbelly and side of the clipper are most vulnerable where pwr. plant is concerned.
To the OP, If you can get to it's side and turn while it's passing, you can get back in control. It's hard to do but often the attempt will frustrate it's lock on you.