Your question is a very topical one because one of the most interesting relationships in this book, in my opinion, is that between Santiago and the sea. Note that his explanation of how the gender of the sea greatly impacts the way that people view it. The younger sailors who seem to be more materialistic refer to the sea using the masculine article, "el," and this causes them to speak of the sea as a contestant in a struggle that they are engaged in or even as an enemy that they fight against. However, for those like Santiago, thinking of the sea as feminine seem to have more of a deeper relationship and understanding of the sea that is the source of their livelihood:
But the old man always thought of her as feminine and as something that gave or withheld great favours, and if she did wild or wicked things it was because she could not help them. The moon affects her as it does a woman, he thought.
Thus it is that the younger generation of sailors, by regarding the sea in masculine terms, view the sea as an enemy or the place of conflict. The older sailors, like Santiago, seem to have a deeper understanding of the fickleness and the capricious nature of the sea because they refer to it using the feminine article, "la."