Can't see any rule broken. Clear ahead and leeward, N has every right to alter course as long as she gives S room to keep clear (16). Once S responds by taking a course to leeward, N is still clear ahead and can alter course (again, as long as rule 16.1 is not broken, which it wasn't in this case. Once S is overlapped to leeward, she can sail proper course and does so. 
Unless I'm missing some nuance in this, it seems like fair sailing.

Any hints Tim?

Seems no rule broken.

What are you getting at?

Juan, assume S was still a few boat lengths astern when N headed up, and N resumed her course when it was clear that S would pass to leeward of her. 

Also assume that when N headed up she put the boats on converging courses & if S had maintained course it's likely that contact would have resulted. 

A ROW boat (N) altering course such that it would result in contact if S didn't alter course is fine, provided S has room to keep clear after N's course change. Clearly, based on the setup and further clarification, rule 16 is not infringed. If pointing your boat on a collision course and forcing another boat to give way were agains the rules, most boats would be thrown out during pre-start. What rule do you think is being infringed and by which boat?

Can these two boats, sailing in different classes with separate starts, be considered to be on the same leg of the course? 

If not, what obligation does that impose? 

I don't see where which leg they are on matters. "The rules of Part 2 apply between boats that are sailing in or near the racing area and intend to race, are racing, or have been racing. "
and "A boat is racing from her preparatory signal until she finishes and clears the finishing line and marks or retires, or until the race committee signals a general recall, postponement or abandonment."

Clearly, they are both racing. So, the rules of part 2 apply. I think even the broadest definition of fair sailing would allow a boat to protect their wind in order to sail the course as fast as possible. 
What obligation (in addition to the rules we've discussed), do you think that imposes? 
I'll admit that, while sailing a 45 footer with an approaching Trans-Pac winner astern, I've decided to foot off and let them go quickly, thinking that I would get around the course faster than trying to hold them off. But, I don't see an obligation to do so in the rules. 

See RRS 23.2. Wondering if people think it applies to this scenario. 

23.2

I think the term "reasonably possible" is doing a lot of work here. I always interpret that as "Don't be a jerk when someone's race doesn't affect you." 
To pose another scenario: what about a boat rounding the weather mark on Starboard and bearing off to sail her course to the leeward mark. Are you suggesting that a port-tack windward boat could protest under 23.2 if she has to alter course to avoid the starboard down-wind boat? 
I don't think so. I think both in your scenario and the one i propose, the ROW boat change of course is reasonable for their race. 
That said, as I already indicated, I may opt to just get out of the way of BADPAK if she's bearing down on me. 

As long as the boat going downwind is sailing her proper course to the leeward mark she's fine under 23.2. But if she alters from her proper course for the purpose of screwing with the upwind boat then yes, the upwind port boat could protest (but would still be obligated to keep clear). 

In my scenario, it's made clear that N changed course for the express purpose of causing S to change course.

Part of my question here is if the boats are sailing legs bounded by the same marks but are in different classes with separate starts, are they on the same leg, or different legs?

I agree that if the downwind boat alters course to "screw with" the upwind boat, the protest could be upheld. But, what if the downwind boat alters course because of other boats on her leg and in so doing requires the port upwind boat to change course (e.g. comes up to protect wind from a boat that rounded after her and is clear astern). That's not "proper course," because it is not the course she would sail if there were no other boats around. Neither is it in order to screw with the upwind boat. 
Coming up to protect your wind against a boat not in your fleet I believe is reasonable. Bearing back off to proper course (and not interfering with the boat now passing to leeward) is also reasonable, in my opinion. But, it's an interesting discussion. I haven't searched cases. Have you found any relevant ones? 

 Hi Tim
I think you have just got to the essence of the scenario. It all comes down to proper course.
 
22.2 ends with

……However, after the starting signal this rule does not apply when the boat is sailing her proper course.

So I think if a boat deliberately goes outside her proper course to interfere with another boat, as in your scenario, she not only breaks 23.2 but also breaks fundamental rule 2.

Paddy

There's another point we haven't addressed, which is whether 23.2 applies at all in your scenario. I think it's an open question as to whether they are "sailing on another leg." There is no definition of "leg" provided. 22 does not mention "sailing in a different fleet." 
They are sailing the same direction between the same two marks. My default would be to apply the rules of section B and C if two boats encounter each other going the same direction between two marks. I don't think it's reasonable to strip a clear-ahead boat of luffing rights because the boat about to roll her is in a different fleet. 

Anthony,that’s the essences of my question. I haven’t seen any relevant cases. My feeling is that different classes with different starts are always sailing on different legs, even if they’re happen to be bounded by the same marks. But I’m interested in what the community thinks.

And I think the scenario I posed happens often enough on the water that it matters.

 Leg 1 is from start to W1.  Leg 2 is from W1 to L2.   Both boats are sailing on the same leg of the course, which is leg 2.
The only rule to apply is Corinthian 1. "A big boat shall not sail above a small boat".
As the big boat sailed below the small boat, all is good and jovial times were enjoyed at the bar post race.

OK. A couple of variations then:

1. S’s course is S - W2 - L2 and so on, N’s course is S - W1 - L2 …. N doesn’t necessarily know what S’s course was, she just knows she’s about to get rolled.

2. S and N are in different regattas with different start lines. So S’s course is S1 - W1 - L2 …. N’s course is S2 - W1 - L2 …. So they’re both on their first downwind which goes from W1 to L2.

You can find some inspiration from MR call L7 q2 regarding if it’s ok to try to get around the course as fast as possible and L9q3 on what is meant with “same leg”. I know these are  match calls, but as the situation is close to same and the rules regarding match and fleet are in this similar, we can learn something from these calls, especially if we can’t find anything from case book.

Hi guys.
my view: to say if boat were on different legs, we hv to assume that, in a W/L course, boat N, that stared earlier, might be, say,  on leg 4, and S on leg 2.
Rule 23.2: "reasonably possible" : agree, lot of room to quibble.
I would give also importance to the word "interefere", which meaning, as per Collis Dictionary, is:
.. If you say that someone interferes in a situation, you mean they get involved in it although it does not concern them and their involvement is not wanted. ..
In the proposed case, the situation do concern boat N, because S was about to slow her. 

Anyway, different leg or not, 23.2 or not,  If action of N was ment to slow S, rather than mantain her own speed,  then that would have been infringement of RRS 2, because N scoring will have nothing to do with final position of S.

Aldo, looking at Case 126, Answer 3, I read that as not differentiating between leg 2 or 4 if they are both leeward legs, in that it is the character (W/L/offset) of the leg and not the number.  I think the Case implies that 2 boats sailing the from the windward to the leeward mark are both on the “leeward leg”, even if one boat is on her 2nd time around. 

Thoughts?

Case 78 lists when it is acceptable for a boat to hinder another. Here there can be no advantage to N as far as her benefitting from the hindrance so none of case 78 would prevent her breaking R2 if it's found she did deliberately hinder S.
However, she is perfectly entitled to protect her wind as that benefits her. So no rules broken.

I think the cases cited (good work finding those) indicate that same leg is the "character" of the leg. So, in Tim's original example, 23.2 would not apply.
I'm still curious about "reasonable." Let's take the case I mentioned:
Two boats overlapped on a downwind leg, both on starboard. W's overlap came from clear astern, so L is entitled to sail above proper course to protect her wind. She does so; no contact occurs. 
I think we all agree up to this point that no rules have been violated. 
Now add a port tack boat on an upwind leg. Assume L's luff puts both boats on collision course with the upwind Port boat. But, Port has plenty of room to avoid and does so.
The downwind boats are clearly on a different leg from Port Upwind and clearly not sailing "proper course," as neither of them would be sailing that course if other boats were not present. 
So, does rule 23 require the SL boat to hold course and let SW roll her? Is that "reasonable?" 
I would argue that it is not "reasonably possible" for the downwind boats to avoid causing the port upwind boat to change course in that avoiding such interference could materially affect the finish positions. I don't think rule 23 was meant to limit the ROW boats that way. 

Tim: this is different from the new scenarios you present, but clearly establishes "different leg" and not on "proper course." I think that lets us talk about what's "reasonable." 
Does rule 23 require a ROW boat with luffing rights to give those up if exercising those rights would force a port tack boat to adjust course? 

Case 126 establishes that a boat is on the leg of the course according to where she is sailing to.  Both boats are sailing towards the leeward mark and therefore on the same leg.  
What if two boats are sailing on the downwind leg to a gate? Are they on different legs if one is sailing toward the left gate mark and one toward the right gate mark?

Anthony makes a good point.  It is not reasonably possible for W to avoid interfering with P because she must luff to keep clear of L.  However, it is reasonably possible for L to curtail her luff and thus avoid interfering with P.
Would W have a case to protest L for a breach of 23.2 if L did not curtail her luff?

"Character of the leg" rather than leg number is definitely different from the way I was thinking about it, but I guess that works. It certainly gets rid of the problems I was contemplating in making the original post.

Since proper course definition depends on which boats and which rules, I think it's different between different pairs of boats with different rules applying between them.

With respect to W and L, rule 11 is in effect between them. L's proper course, in the absence of W, would be lower but she's permitted to sail above it. 

W's proper course is to respond to L's luff and I think this is true whether PU is there or not, so I think W is permitted to sail the higher course even if it interferes with PU.

In the case of L vs PU, rule 23.2 applies between them (so L and PU are the boats referred to in the rule, and L can consider the presence of W in choosing her course). If PU were not there L would come up to prevent being rolled by W. So with respect to PU and RRS 23.2, I think L's higher course is her proper course - it's the course she would sail if W was present and PU was not. 

I agree with your interpretation of proper course. I think that's the simplest interpretation of the definition in that it would be the course L would sail if PU were not there. 
We had a race where two different authorities were using the same bridge pier as mark. It was a windward for one course and a leeward for the other.  Both were required to round leaving the pier to port. You can imagine the headaches that caused, especially since it wasn't always obvious who was in which race. 

Anthony, US97 touches on just such a situation. - Ang

Hi Angelo; answer 3 does not refers to a leg 2/ leg 4 situation (or 6 - 9 as per my example below). 
Answer 3 refers to a course  S - mark1 (w) - mark 2 (offset) - mark 3 (L). 
S - mark1 = leg 1; 
mark 1 mark 2 = leg 2, 
mark 2 mark 3 = leg 3
Boat X was on leg 3, while the boat that missed mark 2 and is sailing upwind to take it, she's, practically, between mark 1 and 2, so she's running on leg 2. That's why they're on different legs.

But say the course was S - 1 -2- 3 -1 -2 - 3 - 1 - 2 -  F (Finish at mark 3), legs would be S - 1= leg 1; 1 - 2= leg 2; 2 - 3= leg 3; 3 - 1= leg 4; 1 - 2 = leg 5;  2 - 3 = leg 6,  and so on.
Two boats may be sailing together,  between marks 2 and 3, with one boat being on leg 6 and the other on leg 9, and 23.2 apply.
Well, that's how's it has been taught to me.

Is there maybe a question to WS in this, asking for a clarification of "another leg" in the context of 23.2?

I think Angelo's interpretation solves a lot of potential problems like the one I posed, but I'm not sure I see that in either black-letter rules & cases or in commonly understood definition of "leg".

And I definitely see Aldo's point. If a course is S - W - L - W - F, most sailors would say that the course has 2 windward legs, not one windward leg sailed two times.

Tim, I think we can get a lot out of Case 126

First, in Q/A 2, L missed the offset and headed to the leeward-mark and 126 states she was on the leg to the leeward mark. 

Next in Q3, L realizes her mistake and turns back to windward. 126 says that now she’s on the leg to the offset mark.  

So in the middle of a leg, one second she’s on one leg and the next she’s on another leg based upon where she is going … not based upon what her “string rule” dictates. 

Aldo, I see your point too.  Case 126 does not answer that question clearly. 

I am not sure of the reasonableness to expect a boat to keep track of which lap other boats are on … especially In fleet racing.  Seems for the sake of effective application of the rules in real-time on the water, the determination needs to be straightforward. 

It is interesting that US97 never mentions “interference”, and solely focuses on the application of 18.   US97 is dealing with boats in different race circles in the same event  (thus diff fleets) using a common mark. 

Angelo I get what Case 126 is telling us but I don't think it gets to the questions. 

Is a boat on her first upwind leg "on another leg" from a boat on her second upwind leg?

Is a boat in class A on her first downwind leg "on another leg" from a boat in class B on her first downwind leg? Does it make a difference whether the classes started together or separately? Does it make a difference if they rounded the same windward mark or different windward marks?

I think the "character of the leg" theory says that all boats on any downwind leg are on the same leg for the purposes of 23.2 but as I say case 126 doesn't definitively get you to that. 

Tim I agree that Case 126 does not definitively answer the question. 

It's been a long-standing feature of the RRS that they enable a boat being overtaken to 'defend her clear wind'.

I don't think we should be searching after interpretations of the rules that take this ability away.

The consequences of preventing a small boat from defending her wind from large boats overtaking her (particularly when those large boats are a whole fleet in succession) are extremely seriouos and unfair to the performance of the smaller boat.

The appication of the rules in this scenario depends on how we construe an apply two words:  'leg' and 'interfere'.

We can apply broader or narrower constructions on those words.

Firstly 'leg'.

It is true that Case 126 does not specifically address the case where boats may sail the track defined by two marks on more than one occasion in a race or when boats sail a track so defined, but in different races.

However Case 126 does use words, without qualification, telling us what 'sailing on a leg' means:

Headnote

a boat is sailing on the leg which is consistent with her course immediately before the incident and her reasons for sailing that course.

Answer 1

a boat is sailing on the leg which is consistent with the course she is sailing before the incident and with her reasons for sailing that course.

I think that a broad, or liberal application of these interpretations to rule 23.2 leads to saying that a boats in different races (or boats in the same race but on different laps) are nevertheless sailing on the same leg whenever they come together while sailing the track between the same two marks [in the same direction].

Unfortuneatly these wordings do not address the case where the boats in question are sailing similar courses but on legs that are coincident or almost coincident, such as on a WL course with a Distant and a Close Windward Mark, specified for larger and smaller boats.

In these cases, I can only argue by extension and analogy from the arguement above to say that they should be treated as if they were on the same leg, because the unfair consequences to the small boat are so severe.

Now for 'interfere'.

We might define 'interfere [with B]' to mean 'to cause B to take some action, or to diminish or make worse the performance of B'. 

Juan posted a question asking whether or not boats were overlapped when the boat ahead (A) changed course to windward, but deleted his post, without pursuing the issue.

I think it does matter.  If A is overlapped to leeward of B and changes course to windward, causing B to fall astern and bear away to leeward of A, there's no way that you can say that A did not 'interfere' with B.

However,  If, while B is clear astern of A, a changes course to windward, and then resumes her previous heading, so that she is now on a similar course but to windward of the course of B, there has been no change in right of way:  until such time as B becomes overlapped to leeward of A, A has always been clear ahead with right of way, but in fact, B has had no 'need' to take any action to keep clear of A (unless A left it very late so that boats were very close and B immediately had to take action to keep clear of A when A changed course.

When A resumes her courses to the leeward mark, now to windward of B's course, again, provided that B is not too close, A is not casting a wind shadow on B or otherwise affecting B's performance.

If A gets a reasonable distance to windward fo B's course, B still has no need to change course or take any other action to keep clear of A before they are overlapped or in order to initially give A room to keep clear when they become overlapped.

So, if these conditions are fulfilled A has not interfered with B and has not broken rule 23.2.

If this argument about the meaning of 'interfere' holds water, it will work for the case where boats are not sailing on the same leg, but are sailing on coiincident or very similar legs. 

John re: “If this argument about the meaning of 'interfere' holds water, it will work for the case where boats are not sailing on the same leg, but are sailing on coiincident or very similar legs. ”

I thought I understood from your comments below that you were arguing that “coincident or very similar legs” resolved to “the same leg” when testing 23.2’s applicability.  

John wrote: 

“Unfortuneatly these wordings do not address the case where the boats in question are sailing similar courses but on legs that are coincident or almost coincident, such as on a WL course with a Distant and a Close Windward Mark, specified for larger and smaller boats.

In these cases, I can only argue by extension and analogy from the arguement above to say that they should be treated as if they were on the same leg, because the unfair consequences to the small boat are so severe.”

Angelo and All,

Before going much further, I'd like to see some feedback about whether people find the arguments I advanced convincing or not.

As it stands, the argument about 'interfere' only works where B is sufficiently far astern of A that B is not immediately required to take any action in response to A's change in course, otherwise, A does interfere.

The problem is resolved more globally if people agree that different incidences of one leg and coincident or similar legs are the same leg, but I don't know if I've won that one.

John, re: “The problem is resolved more globally if people agree that different incidences of one leg and coincident or similar legs are the same leg, but I don't know if I've won that one.”

That’s the argument that I’ve been making and I think Case 126 doesn’t quite walk us to the door, but at least it drops us off at the corner for that one. 

I'm increasingly having trouble with that definition. It leaves it up to competitors on the water and/or a PC to guess the boundaries of "coincident" or "similar."

I think I'd rather make a more narrow definition of "leg". I would say that legs are unique to the ordered course and sequence in the course, so a windward leg for class A sailing Course 1 is different from a windward leg for class B sailing course 2, even if both courses use the same marks. And the first windward leg on course 1 is different from the second windward leg on course 1. That way a competitor always knows whether they're on the same leg or a different leg from a competitor.

With that definition, it's still possible in my original scenario for N ahead to defend her wind from S overtaking. N simply needs to head up early enough and substantially enough that S will pass astern & to leeward without changing course. N has deviated from her proper course but she has not interfered with S. No rule broken.

If S then heads up to continue to try to overtake to windward causing a further course change by N to defend, then S has deviated from her proper course and interfered with N on a different leg breaking 23.2.

Thoughts?

The Cambridge dictionary definition of "interfere" :

If N feels compelled to luff and defend her position, is she involving herself in a situation?  Or is it that she is already involved in that situation brought about by S's choice of course?  
Certainly, when S deviates from her proper course in an attempt to pass to windward of N, she is creating, and therefore involving herself in, the situation in which N feels she needs to defend.  By luffing, N is not involving herself in the situation to which she is already involved.
In this case, I would say that S has interfered with N, but N has not interfered with S.

Honestly, I think everyone is obsessing about a definition of "leg" and "interfere," which as we have seen are not set out clearly in the definitions, when the better approach is to look at the phrase "when reasonably possible."
As far as I can tell, the only other place that phrase appears other than rule 23 is in rule 14, where it is used to limit the responsibility of a ROW boat in avoiding collisions: "A boat shall avoid contact with another boat if reasonably possible."

You don't see "when reasonably possible, a port-tack boat shall keep clear of a starboard-tack boat," for example. 
I think the fact that the term is only used in these two rules sets them apart and we should treat them as such. If a collision occurs and the ROW boat did not avoid, they have not necessarily broken rule 14 because it may not have been reasonably possible for them to avoid. 
What does it mean to act "reasonably" in a situation when a larger boat is overtaking you? Are we saying it's "reasonable" to expect the smaller boat not to protect its wind?  

I don't think it is. 

Anthony,

Firstly, you cannot expect every single word to be defined in the RRS definitions.

It would certainly be nice if the final condition, presently stated as 'if reasonably possible' were somewhat more liberal.  Words like 'consistent with ... trying to win her own [race]', as are found in the Match Racing rules, RRS C2.23, would be helpful.

Unfortunately, those words that would qualify 'if reasonably possible' are not there.

Your argument is based on what is 'reasonable', not on what is 'reasonably possible'.

I don't think that it's possible to read down 'reasonably possible' to just mean 'reasonable'.

Of course not everything can be defined. So, we have to use common sense definitions and get clues from other context. 
Applying an adverb-adjective combination generally means that both roots are satisfied. That is, "reasonably possible" means both "possible" and "reasonable." If the rule had said "safely possible," I would interpret it to mean that it's "possible to avoid by performing a maneuver that is safe." I read "reasonably possible" to mean "possible to avoid by a maneuver that is reasonable."
Perhaps you don't think it works like that. But, that's how I interpret the words. 
But, what meaning of the word "reasonable" should we use?
Here I go to the fact that the word is hardly ever used in the rules. Port/starboard; windward/leeward; even mark room: none of these come with the restriction "reasonably." So, I interpret that to mean that I should not view rule 23 the same way as all the others.

Let's look at the Racing/Not Racing part of rule 23. 
It's 1-minute before the start for boat A who is on port. Air is light and A is 10 boat lengths below the line. B is on Starboard and needs to start making her way toward the line for the next start. She has kept a good distance from the start line, as noted, during A's sequence. She has done, in my view, what is reasonably possible to avoid interfering with boats that are racing. 
But, now she is on a collision course with A. It's certainly possible for B to avoid A. How does "reasonably" modify it? It must modify it somehow, or it wouldn't be there. Since you don't agree with my interpretation of adverb/adjective combinations, how would you say it modifies "possible" in this case?
If avoiding takes B farther from the line and makes her late to the her own start, should she have to do that? If she, the starboard tack boat, holds her course and A has to change course to avoid, has B violated rule 23?

Match racing rule C2.13 (adding new rule 23.3) tends to reinforce my opinion that the "character of the leg" interpretation isn't correct. It would seem to indicate that the rules consider, for example, that the first windward leg for Match 2 is a different leg from the 2nd windward leg for Match 1, and the boats should avoid interfering with each other unless it's consistent with complying with a rule or trying to win their own matches (analogous to sailing a proper course in fleet racing). 

I think I'd tend to interpret "reasonably possible" as a) not impossible; b) not requiring an unreasonable (unsafe, unseamanlike, defying laws of physics, etc.) action. Conversely, "not reasonably possible" includes "impossible" and "possible only if an unreasonable action is accomplished."

Deciding what would or would not have been reasonably possible for a boat to accomplish in a specific incident is why judges get paid the big bucks ;-)

Tim re: MR C2.13

I saw that too ... but where it is certainly reasonable (and necessary) for 2 boats in a match-race to keep track of one another .. , it is a harder prospect in a fleet race with potentially large fleets and potentially mixed-boat handicap racing.   

Also in match-racing  you will have umpire boats in close pursuit .. even more obviously ID'ing these 2 boats as something apart and ID'ing them as being in the same event with each other and in a different event from other boats.

Ang

Angelo, I agree but in my conception boats in different classes (different starts) are always on different legs. It's generally not too hard to keep track of whether another boat in the same class is on the same leg as you or not.

I  think Tim is on  the money with his both boats can break rule 23.2 idea.

That just creates more problems, because in each instance of the rule 23.2 breach, there is no room or mark-room involved, and the other boat cannot be said to have compelled the breach, so no exoneration is available:  If both boats break rule 23.2, then both should be penalised.

That, of course, assumes that the boat ahead (A), luffs to defend her wind, and interferes with the boat behind (B), but not successfully, so that B  gets over theh top of A, and then interferes with her.

I follow Tim's argument against coincident or similar legs not being the same, and agree that MR rule 23.3 supports that idea.

I also understand Angelo's ideas about practicability, but I'm not sure that that is a valid consideration in interpreting the rules (No, Angelo, I don't think it goes as far as absurdity <g>).

Anthony,

I'm not familiar with your grammatical proposition about adverb-adjective combination, but I don't think it holds true in this case.

'Reasonably' modifies 'possible'.  I think that should be construed as 'possible within the bounds of reason', not 'reasonable within the bounds of possibility'.

The test of reasonableness applies to the possibility, not to the action that may be possible.

That's how we apply 'reasonably possible' in, for example rule 14.

I think Tim's analysis of 'reasonably possible' is useful here.

As to you example about boats below the starting line, so B has taken some action to avoid interfering with A, but is still likely to interfere with her.  The question I would be asking is, 'is there anythig more that B could [possibly] do to avoid interfering with A that is not unreasonable. 

John, It is not my grammatical proposition. It is the way adverbs work. The modify verbs or adjectives. In this case, the adverb limits possible to things that are reasonable. 
As for "possible within the bounds of reason," could you please provide an example of something that is possible, but not possible within the bounds of reason? I genuinely don't understand what you mean. 
You pose the question "is there anythig more that B could [possibly] do to avoid interfering with A that is not unreasonable?" 
That is exactly the test I would use (though, I would replace "not unreasonable" with "reasonable." Double-negative constructs are clumsy). 
 Is it unreasonable to expect a right-of-way boat to give up a good start, or give up places in a race, to avoid a give way boat because they are in a different class?" 
I don't think it is reasonable to expect that (or, I think it is unreasonable to expect it). We may just disagree on that.

Anthony, I'd respectfully suggest you're overthinking this. In the case of the pre-start example you propose, Boat A is racing, and has been since her prep signal. Boat B is not, and one minute before A's start, it's unlikely that B will be racing for another two minutes or more (when her prep signal is displayed). It is "reasonably possible" (possible within the bounds of reason, or not requiring an unreasonable action) for Boat B to avoid Boat A, and she must do so, per RRS 23.1.

It seems to me that you're including B's interest in getting a good start among the things that prevent B's avoidance of A from being "reasonably possible", and I submit that gives B far too much latitude to ignore 23.1. B can easily avoid A, and A is the only one of the two of them racing, so B must avoid her. (If A is still loitering around the start line after B's prep signal, the situation will change dramatically!)

Tim, I submit that the situation on a leeward leg is entirely different. Both boats are racing, even if they're not racing each other. Both boats are going in the same general direction, and in many of the examples given above, are headed for the same mark. I submit that it makes no difference if one is coming from a weather mark that is farther away than the other - if they are going to the same place, and coming from the same direction, they are on the same leg, and if they're both racing in a similar direction on legs bounded by completely different marks, they still have the same rights and obligations as they would if they were on the same leg.

In the latter (downwind) case, unless a boat becomes overlapped to leeward from behind within two boat lengths of lateral separation, RRS 17 doesn't apply, and there is no limitation that prevents a ROW boat from sailing above her proper course. If clear ahead, she may alter course as she likes, and if overlapped to leeward, she may luff as she pleases, as long as she gives the keep clear boat room to keep clear (BTW, a boat cannot be both clear ahead and to leeward - being to leeward requires an overlap, so the terms are mutually exclusive, as defined). In the case where those same two starboard tack downwind boats encounter a port tacker coming upwind toward them, their obligation not to interfere with the port tacker (who is on a different leg) is limited by what they're doing to avoid one another (recall that proper course is defined as the course the boat(s) "would choose ... in the absence of the other boats referred to in the rule using the term." The "other boats" in this case is the port tacker, not the boat to windward or clear astern of the downwind starboard tacker. If you have right of way over me and are avoiding another boat's wind shadow, and your course takes you into my way, I'm still the give way boat, and you are still sailing your proper course in relation to me.

With due respect to all, I submit that the MR Calls under discussion exist for different reasons, and are a distraction here. As you know, match racing is usually conducted in a round robin or knockout format with several races on the same short race course at once. All of those boats are competing with one another, even if they may be in separate matches at a given moment. That means that one boat may make a short maneuver to mess with another boat's position in a different match in service of their own position in the round robin or knockout, and the calls are intended to prevent such surprise attempts to torpedo a competitor in a different match, because they're dangerous. Note the limitation on the prohibition against such maneuvers is that a ROW boat may act as she pleases in aid of winning her own match, as long as she complies with RRS 16. An example of such a maneuver might be to use her right of way to prevent a boat in a different match from blanketing her on a downwind leg and allowing her match opponent to pass and beat her (a loophole that can get much bigger in a match race, since RRS 17 is deleted).