The phrase "the briny deeps" is often used to describe ocean waters, but there are many other synonyms that can also be used. For example, "the blue abyss" can evoke a sense of the deep, endless expanse of the ocean, while "the saltwater realm" suggests a magical and mysterious place. "The indigo depths" conjures images of the dark and foreboding ocean floor, while "the aquamarine vastness" brings to mind the endless depths of the sea. "The navy blue beyond" captures the idea of exploring uncharted waters, while "the fathomless depths" can suggest the unfathomable mysteries that lie beneath the surface of the water.