Whirlpool

Just a snippet:

She was flung viciously, haplessly, dizzily round the lip of the thirsty maw. Suddenly the whirlpool disappeared, leaving her staring raggedly at an inky sea.

She watched as splintered shards of her little boat began to surface, tinged by the dying golden rays of the westering sun. There was no hint of land in sight. any sense of direction had been snatched away by the vertiginous whirling.

Just as she was remembering the sun's direction, it gave a last piercing green flash and sank into the mountainous, frigid waves. It would be a long night of treading water.