When rule 22 or 23 applies between two boats, Section A rules do not.
23 INTERFERING WITH ANOTHER BOAT
23.1 If reasonably possible, a boat not racing shall not interfere with a boat that is racing.
23.2 If reasonably possible a boat shall not interfere with a boat that is taking a penalty, sailing on another leg. or subject to rule 21.1. However, after the starting signal this rule does not apply when the boat is sailing her proper course.