I saw from port a vessel steer

I saw from port a vessel steer, The skies were clear, the winds were fair, More swiftly than the hunted deer, Upon her snowy wings of air, She flew along the silv'ry water, As fearlessly as if some sprite, Familiar with the deep, had taught her, A spell by which to rule the might Of winds and waves, when met to try Their strength, up midway in the sky.