17.1 If a boat clear astern becomes overlapped within two of her hull lenghts to leeward of a boat on the same tack, she shall not sail above her proper course while they remain overlapped within that distance.
The leeward boat had no rights to luff the windward boat and should accept a DSQ, if the windward boat protested and the lee boat did not do her turns.
BUT if the boats have differing "proper courses" say a Dingy and a Cat, and cat passes to the lee of a boat sailing a deeper course, then once overlapped to leeward within 2 boat lengths you are sailing your proper course and windward boat should keep clear. ?????
