The old man is the ego. The girl is the soul. The ocean is the world. The boat is the physical body. The guests that come fishing are the thoughts. The bow is the consciousness. The young man is the supreme Self, Atman.
The act of shooting the arrow from the bow is the act of meditation, an act where the consciousness is perfected, united and becomes an unstoppable power.
The dual functions of the bow - as a weapon that has an overwhelming power yet it is also an instrument of art and beauty - represent the two aspects of the consciousness - Cit and Ananda, Cit = consciousness (arrow) and Ananda = beatitude (music).
The way the old man was protecting the girl is the fight of the mind to keep the soul pure and intact. The visitors (impure thoughts) were attempting to spoil the purity of his soul while he was protecting it with the bow (his focused consciousness, or could be by a state of meditation, because in a meditation the mind becomes as focused as the arrow shot from a bow).
The fortunetelling is a meditation where the soul is providing answers to mind. The answers first appear in the soul, in a state of meditation (the shooting of the bow). Then the soul (the girl) shows the mind the answer.
The moment when the girl was rejecting the old man's hand at night is the moment when the ego is alone, separate from his soul, in a dark night of suffering that is necessary for it to understand his mistakes.
The old man's attempt to stop the girl leaving by sacrificing his life is the sacrifice of the ego that is necessary for the soul to become free. Only after the ego completely sacrifices itself, can the soul become free to discover the supreme self, Atman.
The death of the old man was the death of the dual mind and ego. The girl's orgasm is the ecstatic expansion of the soul and that marks the moment of supreme Liberation. The arrow plays the role of the consciousness that penetrates the soul and makes it expand with infinite joy into a state of union with the supreme Self - represented here by the young boy who was holding the girl.
The sinking of the boat represents the death of the physical body. The girl leaving together with the boy represents the life after the supreme Liberation, where the soul is together with the supreme Self (or with God).