Windward boat

The International Regulations for Preventing Collisions at Sea (i.e. the NON racing rules) still have an "overtaking boat keeps clear", but the racing rules only have clear astern / clear ahead and windward / leeward rules.

The windward boat has to keep clear. But windward doesn't need to anticipate the need to keep clear until the overlap exists. Once the overlap is created, they have to keep clear (luff / tack etc.) If the change of course they make while keeping clear (stern swinging) hits leeward boat, then leeward is in the wrong (not giving enough room).

What do you mean by "luff"? L can sail her proper course, which may be higher than W's proper course. L can't put the tiller down hard, which is what is usually meant by a "luff".

I'm not too sure the rules have changed in this respect. What did fundamentally change a decade ago were the rules around what L could do if threatened by W, with the demise of the "mast abeam" curtailment of luffing rights.

It's a little simplistic to say there is "no overtaking rule". Rule 17 discusses what a boat which establishes an overlap to leeward from astern can and cannot do. Establishing an overlap from astern is "overtaking" even if that word isn't used.

My understanding was always

If boats are racing, whether or not they are in the same race, shared the same start or sailing the same course, the RRS apply.

A racing yacht has right of way over a cruising yacht under the collision regs. (in days gone by, a square burgee indicated a racing yacht, a triangular showed cruising)

Non-racing yachts are governed by the collision regs.

No doubt someone will tell me if I'm wrong.

Ian