SECTION D OTHER RULES
When rule 21 or 22 applies between two boats, Section A rules do not.
21 STARTING ERRORS; TAKING PENALTIES; MOVING ASTERN
21.1 A boat sailing towards the pre-start side of the starting line or one of its extensions after her starting signal to start or to comply with rule 30.1 shall keep clear of a boat not doing so until she is completely on the pre-start side.
21.2 A boat taking a penalty turn shall keep clear of one that is not.
21.3 A boat moving astern or sideways to windward through the water by backing a sail shall keep clear of one that is not.