CABIN MOTORBOAT WAS RETURNING TO OWNER'S DOCK  FROM DAY OF FISHING. DUE TO DARKNESS, OTHER BOATS IN THE VICINITY, OPERATOR ATTEMPTED TO STAY IN THE CHANNEL & AWAY FROM WEEDS IN CHANNEL. ANOTHER BOAT BLOCKED CABIN MOTOR BOAT'S RADAR FROM DETECTING CHANNEL MARKER. BOAT COLLIDED WITH CHANNEL MARKER CAUSING DAMAGE TO THE BOAT.
STURGEON BAY                  