The SI's are amended to include the possibility to change a leg in the event a mark is blocked by dredging operations. 17. Change of the Next Leg of the Course If the Race Committee displays the “C” code flag, all classes will sail the changed course. In case more or more of the fixed marks are blocked by dredging operations, the race committee will drop an 8' yellow tetrahedron on a new bearing to the left or right, and provide the new coordinates on the water over VHF 69. The course distance will not change.