Diana swims through rough water

Diana felt the cold water beyond the boundary engulf her fully.  The sea had her now, and it was not friendly.  The current seized her legs, dragging her down, a massive rolling force, the barest shrug of a god.  You have to fight it, she realized, demanding that her muscles correct her course.  She’d never had to work against the ocean.
She bobbed for a moment on the surface, trying to get her bearings as the waves crested around her.
...
Another wave rose, a great gray mountain.  Diana dove beneath it, kicking hard, then surfaced, searching, bits of lumber and fiberglass everywhere, impossible to sort one piece of flotsam from another