Section D contains rules that apply in special situations that arise on the race course (rules 21–23). Again, these rules contain times when a right-of-way boat may find herself with a temporary obligation to keep clear of, or other- wise avoid, a keep-clear boat. An example is if you are on port tack shortly after the start and a starboard-tack boat is sailing back to the line because she was over early, rule 21.1 (Starting Line Errors; Taking Penalties; Backing a Sail) requires her to keep clear of you because you have started correctly, even though she is on starboard tack and you are on port tack. In this case you become the right-of-way boat and she the keep-clear boat for as long as the rule requires her to keep clear. Another example is that all boats are required to avoid a boat that is capsized, whether holding right of way over her or not (rule 22, Capsized, Anchored or Aground; Rescuing).
P R E AMB L E T O S E C T I O N D When rule 21 or 22 applies between two boats, Section A rules do not.
This preamble clarifies that whenever rule 21 (Starting Errors; Taking Penalties; Backing a Sail) or rule 22 (Capsized, Anchored or Aground; Rescuing) applies, it takes precedence over the basic right-of-way rules in Section A. Note, how- ever, that the rules of Section B still apply, which most significantly means that rule 16 (Changing Course) applies to a boat given the right of way in rule 21.
