Assumptions:
-Downwind finish and this is the finish (orange and blue flags are confusing)
-The class rules haven't specifically included the sprit or foils in the definition of finish. 

Neither has finished. 

green

Reading the q&a, green yes, yellow no. 
https://www.sailing.org/tools/documents/QA2021.002v3-%5B27236%5D.pdf

Agreed John, the flags ARE confusing! When any part of the racing craft, in it's natural position breaks the plane. Both have finished...long before the diagram.

If we ignore the flags! I agree Green has finished as part of her hull has crossed the line. Yellow has yet to finish as only the bowsprit has crossed and under the new definition is not part of the hull.

I suspect the confusion here may be over use of the term "wing" in the Q&A highlighted by Juuso. I'm pretty sure that when the Q&A talks about "wings" it means racks, as in extensions of the deck that allow the crew to position themselves outboard of the hull. If that is what the black blobs in the diagram are intended to represent then Green has finished but not Yellow.

If on the other hand the black blobs are intended to represent the hydrofoils that allow the skiffs to "fly", then in my view those are hull appendages but not part of the hull itself, and in that case neither boat has finished (c.f. definition of hull appendage, wing and foil in the ERS).

@John Porter: Class rules cannot change the definition of Finish, but might possibly be able to say that the term "hull" as used in the definition of Finish is to be interpreted as including the bowsprit and/or foils.

@Robby Hill: You might like to read the new rules. A boat does not now finish until part of her hull crosses the finishing line.

https://www.sailing.org/tools/documents/QA2021.002v3-[27236].pdf

ERS for 2021-2024 amended the definition of "foil" to "hydrofoil":

So a bowsprit is a spar (unless otherwise defined in class rules, per Q&A) and the hydrofoils are hull appendages per ERS. Neither are part of the hull.

Under 2017-2020 rules both have finished (equipment in normal position has crossed) but under 2021-2024 rules neither have finished (hull has not crossed).

If one plays with the required preciseness, I would also be more precise about the requirement of  J2.1(5) descriptions of the starting and finishing lines, which is as standard, described in APP S 11.1 as : "The finishing line will be between a staff displaying a blue flag on the race committee vessel and the course side of the finishing mark."  

I can see where using a blue flag would be helpful when the start and finish lines are separate, especially when they're on either side of a committee boat that bounds both (and in that case I can see where the committee boat would display both a blue and an orange flag). But for races with one common S-F line is the RC really going to switch out flags on the pin between the start and the finish? Or just define it away in sailing instructions?

The orange and blue flags might indeed be flown from the same staff, according to "the Daves."

The QA posted above is interesting. The class rules or rating rules determine if the ERS definition of hull is used. This is also backed by the introduction in the ERS where its applicability is stated.

So to answer the threads question we have to ask which rules and definitions apply.
notice of race -> class/rating rules -> ERS or otherwise defined


I want to also point out that "wings of a skiff" are not the same as a hydrofoils or winglets (when the ERS apply).

Example: IMOCA 60
‘Bold’ refer to an ERS definition. 'Italics' refer to CR Definitions.

Foil: A hull appendage primarily used to produce lift and/or affect leeway or stability or elevation or righting moment.
D.2 Dimensions
(c) The beam of the hull shall not exceed 5850 mm.

This results in the foils, as hull appendage, not being considered as part of the hull.
But how can any race officer know all the different class rules and their definitions you may ask. For most one-design-class regattas it is not so difficult. And in the multi class events you can define your interpretation of hull in the rating rules.

Sorry for the long winded answer. For most classes yellow and green have not finished.

Forget the flags......i swear it's a FINISH LINE.

Neither has finished. 

Catalan,
may I ask which class this is? Because from the pictures I can't be quite sure whether the black things are hydrofoils or wings of a skiff (like 49er wings).

So good point Hans !!!!
.....exactly this is what i am studying with my friends at the club !!!

WINGS OF A SKIFF Iand HYDROFOIL are  THE SAME ????

In this picture we can see the wings of a skiff (like 49er wings).

 It is there in the Q&A. In ERS says that deck superstructue is part of the hull.