checked the chart carefully for any off lying danger off the cape and thought I could safely round it half a mile off in safety.  As I approached the cape a favorable current was carrying us along nicely.  I noticed what I though was a tide rip ahead, but it looked out of place with the surrounding water.  Through the binoculars I saw a low brown object in the water.  For a moment I thought it was a whale, but there was no movement, the water was rushing past and over it.  A rock awash!