The thing about that kind of symbolism is that it works best when you don't even consciously notice it. The talk of the boat anchor just primes you into thinking in a certain manner, then the author hits you with the girl-father story and you see it through that lens. Or the symbolism puts you in a particular emotional state which enhances your experience of the book, much like background music in a film.

Unfortunately it's often taught at school as if it's some kind of exercise in decryption.