The Stormy Sea

You are at sea.  Your ship is sound, having passed all pre-departure checks with flying colors.  The waves are calm, beating a slow, low rhythm against the hull.  You climb the rigging and reach the crow’s nest for another long, boring day of keeping watch along the horizon for any signs of trouble.  Hours of this go by with no end to the plainness of the blue-on-blue horizon line of water meeting sky.  Then suddenly, a small patch appears to the west.  You think nothing of it for a while, but...