I was also surprised of how different she looked in this film. First, her make-up made her look much older than she was at that time (only 43), and second, in general, she seemed to just not care of what people will think of her. She didn't play a sexy femme fatale or whatever, she played a spoiled rich bitch being humiliated on the sand by a fisherman! And even kissing his feet at one scene!
It wasn't a great performance by all means, she was never a great actress, but at least it was honest. And for me, her transition of turning from a bitch to a real woman with human feelings, worked, and that's what matters. It wasn't a well-written character, and the screenplay didn't go deep to her relationship with the skipper, that's why it wasn't a great movie, but it wasn't bad either, I had a good time.