SECTION D - OTHER RULES
When rule 20 or 21 applies between two boats, Section A rules do not.
20 STARTING ERRORS; PENALTY TURNS; MOVING ASTERN
20.1 A boat sailing towards the pre-start side of the starting line or 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.
20.2 A boat making a penalty turn shall keep clear of one that is not.
20.3 A boat moving astern by backing a sail shall keep clear of one that is not.