I think the 'fiery ringlets' are the little waves around the prow of his boat, caused by the prow pushing quickly through the water. They are startled from their sleep as it were, by this unexpected boat (after all, it's night). As for the 'pushing prow', I think it simply refers to the front of the boat landing on the beach.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.