Follow up: I have been told that Q&A 2008-002 covers this. While I think Part 1 doesn't (as it is about whether 'normal position' also applies to the the hull), the answer in Part 2 about to the crew states: "Yes. It is normal for dinghies to capsize and therefore a capsized dinghy and its crew in the water are in a normal position." — If one follows that argument, also a mast top in the water is in the normal position (for a dinghy) and, hence, the crossing of the mast top counts.

This has happened to me a number of times - as a sailing question, not a judging/rules question.

My first challenge has always been to right the boat and get it sailing again. My second challenge was to convince the race committee that capsized WAS my normal position and the top of the mast should indicate my finish. Usually they, and the rest of the fleet, are laughing by then and happy to agree. I suspect the members of the 2008 Q&A Panal had shared my experiences.

Unlike easing out the spinnaker halyard and sheets, it would be difficult to sucessfully argue that the capsize was on puporse and to gain an advantage. But, if the race committee came to that conclusion, I would recommend they took the first hull fitting as the finish moment and let the boat ask the protest committee for redress.

I can remember a slide shown at an IRO seminar a while back of a multihull going bow down just in front of the finish line and one of the crew being thrown forward. The body of the crew was crossing the line while in the air ahead of the boat but still managed to have a hand attached. The boat was deemed finished at the first instance the crew crossed the line as he was in the normal position for a boat catapulting.

What is “normal position”? If the mast is still in place, it is in it’s normal position. If the boat is capsized, is it normal for the mast to be in the water while capsized? For me, the answer would be yes, the mast is in it’s normal position for a capsized boat, and if that is the first part of the boat that crosses the line, then I would give it a finish at that time.

Was not a multihull, but a 49er.  Photo in question:

And the consensus was: that's normal for a 49er in heavy air.  (2008 Olympics medal race.)

As somebody who sailed an International Canoe a long time ago, I can testify that the capsize position was normal for me.  https://www.sail-world.com/photo/177620

At the 2017 29er Worlds we had to ask one competitor their sail number as the floated across the finish line upside down.

Q&A 2008-002 link

http://www.sailing.org/tools/documents/QA%202008%20002-%5B5782%5D.pdf

Question 2
With respect to the definition of Finish, the Terminology paragraph of the Introduction and the second part of rule 47.2, does a capsized boat correctly finish if she crosses the finishing line when:
a) all of the crew members are (somehow) on board even though the boat is capsized,
b) some of the crew members are not on board but are very close to the boat and trying to straighten it out , and
c) some of the crew members are not on board because they have become disconnected from the boat and its equipment, but are swimming to reach the capsized boat?
Answer 2
Yes. It is normal for dinghies to capsize and therefore a capsized dinghy and its crew in the water are in a normal position. It follows that a boat finishes correctly in all of the conditions stated in the question.
Also, the boat does not break rule 47.2 while the crew are making all reasonable attempts to recover the boat and get back on board provided they are not making any attempt to progress the position of the boat in the race. If they attempt to ‘swim’ the boat across the finishing line, they would break both rule 47.2 and rule 42.1, and possibly rule 2.

If I may mention a private matter, I was eager this topic becomes an object of discussion.
1. ISAF E 004 Q&A 2015.011 says as follows;
Question 1
If a boat is capsized and the hull crosses the finishing line, is she considered as finishing the race?
Answer 1
Yes. See the definition Finish.
Question 2
If the answer to question 1 is yes, must the crew be in physical contact with the boat?
Answer 2
The definition Finish does not include any requirement about the crew being on board, however, rule 47.2 requires that any crew that has left the boat either by accident or to swim must be back on board before the boat continues in the race. A capsized boat that crosses the finishing line will finish as per the definition, but will break rule 47.2 if the crew are not in contact with the boat, except when they are in the water trying to right the boat. See answer 3.
Question 3
After part of the boat's hull crosses the finishing line, the crew get back on board. The boat returns to the course side and then crosses the finishing line again. Is this now a finish for the boat?
Answer 3
Yes. Her original crossing of the finishing line is no longer relevant, because she has continued to sail the course - see the definition Finish, (c).

2. ISAF Q&A 2008-002 says as follows;
Question 1
With respect to the definition of finish, does the condition "in normal position" refer also to the hull?
Answer 1
No, the normal position refers to crew or equipment only. The commas before and after “or crew or equipment” in normal position limit the normal-position requirement only to the crew and equipment.
Question 2
With respect to the definition of Finish, the Terminology paragraph of the Introduction and the second part of rule 47.2, does a capsized boat correctly finish if she crosses the finishing line when:
a) all of the crew members are (somehow) on board even though the boat is capsized,
b) some of the crew members are not on board but are very close to the boat and trying to straighten it out, and
c) some of the crew members are not on board because they have become disconnected from the boat and its equipment, but are swimming to reach the capsized boat?
Answer 2
Yes. It is normal for dinghies to capsize and therefore a capsized dinghy and its crew in the water are in a normal position. It follows that a boat finishes correctly in all of the conditions stated in the question.
Also, the boat does not break rule 47.2 while the crew are making all reasonable attempts to recover the boat and get back on board provided they are not making any attempt to progress the position of the boat in the race. If they attempt to ‘swim’ the boat across the finishing line, they would break both rule 47.2 and rule 42.1, and possibly rule 2.
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3. My study-1;
I know well that the Q&A service is not to be used as a 'substitute' appeal process, but is simply to provide considered opinions on questions on the RRS.
As compared with both Q&As, I think that it is not necessary the crew must be back on board. Because it is normal for dinghies to capsize and therefore a capsized dinghy and its crew in the water are in normal position. I am convinced that the old Q&A 2008-002 is correct.
　
4. My study-2;
In case of Windsurfing, when a "board" is capsized and the hull crosses the finishing line, is she considered as finishing the race?
If Q&A 2015.011 is valid, must the crew be in physical contact with the windsurfing board?
And must the board return to the course side and then must crosses the finishing line again?
No. Because rule 47.2 is deleted in WCR 2017-2020 B4.
Therefore, the Q&A 2008-002 is much better and fair than Q&A 2015.011.

Thanks.

Is there anybody who notices the Racing Rules Committe recommendation

to the next RRS 2021-2024 on the World Sailing website?

There must be RRS 47.2 revised edition. It may serve as a reference.