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Rule 10 while RoW boat is changing course - Appendix E
Johan Bergkvist
Nationality: Australia
0
Two boats are beating upwind. As Yellow boat sails in front of Blue boat, a large wind-shift to the right leaves Yellow boat with flapping sails and loss of speed. Yellow boat turns right while Blue boat also turns right to adjust for the new wind direction. While both boats are turning, Blue hits Yellow. There is no damage.
Does Blue break R16.1? If so, is Yellow exonerated from R10 by R43.1(a)? This did happen, but is not the subject of a protest or appeal.
Created: 24-Apr-13 12:26
Comments
John Porter
Nationality: United States
Certifications:
National Judge
Club Race Officer
2
Yes, blue breaks 16.1. Yellow breaks Rule 10. Yellow is exonerated by 43.1.
Of course, it needs to be proven in the hearing that indeed there was a lift, that blue changed course, and that yellow would have crossed in the absence of Blue's luff.
Created: 24-Apr-13 14:41
Ted Everingham
1
I agree with John.
Created: 24-Apr-13 15:30
John Christman
Nationality: United States
Certifications:
Club Race Officer
National Judge
National Umpire
1
If you take a look at US Sailing Question 33, I think you will find your answer. Blue's desire to follow the lift requires her to comply with rule 16.1 as she is changing her direction or compass course. In position 1 Yellow is sailing a course that will not require Blue to maneuver to avoid her and therefore she is keeping clear at that instant. As the situation progresses, Yellow reaches a point where she is committed to continuing straight to continue to keep clear of Blue. She can no longer tack or duck Blue. If Blue alters course and, as a result of that course change, Yellow can no longer continue to keep clear, then Blue has broken rule 16.1. Blue can "unbreak" rule 16.1 by continuing to alter course and giving Yellow the room she needs to continue to keep clear of Blue. See WS Case 147.
Another way to think about this is that whenever a boat changes course she must give all the keep clear boats a way out, they have to have a way to keep clear.
I'm not sure how Appendix E fits in here. There are no rule changes there that would change this answer.
A helmsperson on a beat to windward may be focusing on the state of their tell-tails and shape of her jib's luff and not realize she has "changed course" to windward/leeward as she keeps her boat "on the wind". This is especially true if there is no shoreline with clear landmarks.
Depending on the amount of weather-helm she's sailing with, a boat will change course with little or no input from the helm. In that case, it might take significant inputs from the helm [sailing the boat "off the wind"] to 'hold course'.
In my discussions with some sailors, I have found that some sailors believe that, in these P/S to windward situations, riding up a lift while holding helm is 'holding their course'.
I was in a P/S protest a while back .. I was the protestor S. I held course and had to alter to leeward to avoid 1/2 BL from P. During the hearing, P stated they saw me turn my wheel as we approached each other and asked me if I held my wheel steady or if I turned my wheel. My response was that I was holding my course on the shoreline and turning my wheel to maintain my course. Also on my boat, my wheel has an approximately 9:1 turning ratio Wheel -> Rudder. So a +/- 2 degree movement at the rudder (4 deg total) looks like a 36 deg movement of my wheel.
To someone used to sailing a tiller, that might appear to be large rudder inputs when it's actually not (depending on the wind and seas).
But the point being 'not changing course' (holding course) is often a 'deliberate action' which takes attention and intent. One sometimes cannot just stay "on the wind" and at the same time 'not change course'
Created: 24-Apr-14 12:52
Johan Bergkvist
Nationality: Australia
0
Thanks for clarifying that for me!
What about if the PC had decided that Yellow would not have cleared Blue had both boats maintained their original courses (as indicated in positions 1)? I'm guessing Yellow broke R10 with no exoneration and Blue broke 16.1, even though Blues course change did not affect the outcome?
Created: 24-Apr-15 11:06
P
Angelo Guarino
Certifications:
Regional Judge
Fleet Measurer
0
Johan re: "What about if the PC had decided that Yellow would not have cleared Blue had both boats maintained their original courses (as indicated in positions 1)? I'm guessing Yellow broke R10 with no exoneration and Blue broke 16.1, even though Blues course change did not affect the outcome?"
When we talk about PC's in this context, we talk about PC's doing 3 things...
Find (and then declare) what the pertinent facts are about the incident
Conclude what if any rules were broken by which boats and if those boats are exonerated for breaking those rules
Decide what the appropriate penalty is for any unexonerated breaches of the rules and if a penalty is to be applied by the PC (sometimes a boat already took the appropriate penalty).
So, following that guideline let's look at your question (which no longer aligns with your OP drawing). Let's assume the following Facts Found.
FactsFound
Blue on S and Yellow on P were on a beat to windward on converging courses during the 1st windward leg.
Both boats were J/105's traveling at 6kts in 10kts of breeze (10.5m/34.5' BL, 3890kg/8576lb min-WT).
Had both boats each held their course when Blue was 2 BL's from Yellow, Blue's bow would have made contact with Yellow's starboard rear quarter 1 foot forward of Yellow's stern.
From when the boats were 1-3/4 BL's apart until they were 1 BL apart, Blue altered course to starboard and Yellow altered course to port [starboard] in response to a wind shift. This moved the course-intersection point forward to mid-ships on Yellow's starboard side.
Blue's bow made contact with Yellow's starboard side at mid-ship.
From 1 BL separation until contact occured, neither boat altered course.
Contact caused a 5"x4" indentation in Yellow's hull at the toe-rail with fractures in the fiberglass skin. There was no damage to Blue. There were no injuries on either boat.
OK .. these are the FF's for your new scenario. Anyone want to take a stab at the Conclusions and Decision?
Created: 24-Apr-15 11:45
P
John Allan
Certifications:
National Judge
Regional Race Officer
0
Conclusions
Y on port tack did not keep clear of B on starboard tack. Y broke RRS 10.
B, a right-of-way boat changing course did not give Y room to keep clear. B broke RRS 16.1.
Y, sailing within the room to which she was entitled was exonerated for breaking RRS 10 by RRS 43.1(b).
It was not reasonably possible for Y to avoid contact. Y did not break RRS 14.
It was reasonably possible for B, acting no sooner than it was clear that Y was not keeping clear, to avoid contact and she did not do so. B broke RRS 14.
Decision B is disqualified in Race n.
Comments I don' think Angelo's FF 2, beyond saying that boats were on a collision course is relevant, and its a brave protest committee that states a point of collision with 1 foot from 2 BL out.
When a right-of-way boat changes course, the keep-clear boat is required to act only in response to what the right-of-way boat is doing at the time, not what the right-of-way boat might do subsequently.
Stepping back:
When [boats ar so close that] a right-of-way boat needs to take avoiding action (Case 50), and does so by changing course, the give way boat has already broken the relevant right-of-way rule, so the right-of-way boat’s change of course is not denying her room to keep clear, and the right-of-way boat does not break RRS 16.1.
So unless the protest committee concldes that , whe the right-of-way boat changed course, boats were so close that the right-of-way boat needed to take avoiding action, and that changing course as she did was avoiding action, RRS 16 applies when she changes course.
In this case B changing course to windward and reducing the space between herself and Y cannot be characterised as taking avoiding action and B is left on the hook for RRS 16.1
Created: 24-Apr-15 12:56
P
Angelo Guarino
Certifications:
Regional Judge
Fleet Measurer
0
John re: "I don' think Angelo's FF 2, beyond saying that boats were on a collision course is relevant, and its a brave protest committee that states a point of collision with 1 foot from 2 BL out."
That was needed to satisfy Johan's requested condition for scenario change. He wanted us to establish that they would have made contact if both boats held course at position 1.
Created: 24-Apr-15 12:59
P
Angelo Guarino
Certifications:
Regional Judge
Fleet Measurer
0
John re: "converging course", "collision course" and stating as a fact where contact would have occurred
John, you bring up a protest-decision writing style point which is interesting but maybe a bit off topic.
For me, I personally shy away from the phrase "collision course" in decisions because I personally feel that "collision" implies damage and also it doesn't convey where contact would have occurred.
So personally, I use "converging course" to first establish that boats are sailing toward each other. Then in a separate statement, I like describe where contact would have occurred on the boats had one/the-other/neither boat altered course from a stated distance.
It's my personal feeling that this gives an Appeals Committee or subsequent PC the ability to lay the models out or make a drawing depicting the conditions we assumed.
If you think this topic is worthy of further exploration, maybe we should open a separate thread and invite others to chime in?
Created: 24-Apr-15 13:18
P
John Allan
Certifications:
National Judge
Regional Race Officer
0
Ang, I agree that I usually prefer to say 'converging courses'.
But 'collision course' quite often gets a run in the Case Book.
While I wouldn't usually use the phrase in a written protest decision, I sometimes find the concept of 'risk of collision' as defined in IRPCAS useful, particularly when determining when a RRS 16 obligation starts
In determining if risk of collision exists the following considerations shall be among those taken into account: (i) such risk shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change;
Created: 24-Apr-15 14:03
Johan Bergkvist
Nationality: Australia
-1
Restating the second scenario and using Angelos approach... Facts Found:
Blue on starboard and Yellow on port were on a beat to windward on converging courses.
Both boats were DF95 (2kg) in 5 kts of breeze.
Had both boats each held their course when Blue was 2 BL's from Yellow, Blue would have hit Yellow aft of midships.
From when the boats were 1-3/4 boat lengths apart until they were 1 boat length apart, Blue altered course to starboard and Yellow altered course to starboard in response to a wind shift. This moved the course-intersection point forward to mid-ships on Yellow's starboard side.
Blue's bow made contact with Yellow's starboard side at mid-ship.
From 1 boat length separation until contact occurred, both boats continued to alter course to starboard.
There was no damage to either boat.
Yellow performed a 360 penalty turn.
Conclusions
Yellow on port tack did not keep clear of Blue on starboard tack. Yellow broke RRS 10.
...?
I feels odd that Yellow might get exonerated just because Blue altered course. I get that Blue can't hunt Yellow, but to disregard R10 seems wrong?
Created: 24-Apr-16 09:08
P
John Allan
Certifications:
National Judge
Regional Race Officer
0
Digging a little deeper into the reasoning.
In the OP scenario, Y is initially keeping clear, and B ceases to give Y room to keap clear @2-delta, as B continues to change course and there is insufficient time and space for Y to change course to windward and tack away.
In the latest example, @1, Y is only keeping clear because boats are not yet close enough for B to need to take avoiding action.
There is nothing to constrain Y from tacking away to keep clear, and if she acts promptly at this point by tacking she can keep clear.
So from the time risk of collision exists, Y has all the room in the world to tack away.
Anybody think ì should revisit my conclusions on Scenario 1B?
Created: 24-Apr-16 10:25
P
Angelo Guarino
Certifications:
Regional Judge
Fleet Measurer
0
Johan, thanks for finding my mistake/typo. I didn't intend to change their turning directions from your OP image. (Fixed now in my comment)
John, I don't think my mistake would change you writeup. IMO Blue is committed to moving forward and so needs to keep moving quickly forward by keeping her sails driving .. but maybe you want the opportunity to edit it.
Being J/105's 6kts is ~ 3m/s so a little over 3 sec per BL. A "fast tack" is 3-4 sec's. Where a tack that optimizes height and exit-speed is more like 5-6 sec's in that breeze.
Created: 24-Apr-16 10:50
P
Angelo Guarino
Certifications:
Regional Judge
Fleet Measurer
0
Johan, it's all about the time until contact vs time it takes to tack. That's the point John's starting to describe.
So, I'd ask 2 Q's
In 5kts of breeze, how fast does a DF95 travel in terms of secs/BL?
How many sec's does it take a boat to do a 'fast tack' and a 'normal tack'?
Created: 24-Apr-16 11:05
Johan Bergkvist
Nationality: Australia
1
Angelo, I'd say Y could not tack away in time. Add that to Johns comments and I now see why Y would be exonerated.
As a thank you! to both of you, here's a treat for any PC; the OP situation in full color! I'm including it for your amusement, not necessarily to continue the discussion. ☒
Created: 24-Apr-16 11:20
P
John Allan
Certifications:
National Judge
Regional Race Officer
0
Not sure if I was clear in my last post.
OP scenario, Y initially keeping clear by passing ahead of B, ie, not on a collision course.
B' change of course deprives Y of room to keep clear, and Y has no time to tack away. B breaks RRS 16.1 and Y is exonerated.
Last scenario, initially boats are on a collision course, Y has to do something to keep clear, there is both space and time for Y to tack away. B's change of course doe not affect the room available to Y to keep clear by tacking. B does not break RRS 16.1, Y breaks RRS 10 and is not exonerated.
The mark room to which Y is entitled us out there on her port side, and she's not sailing within it.
Created: 24-Apr-16 11:47
P
Angelo Guarino
Certifications:
Regional Judge
Fleet Measurer
0
John, do we have a case or appeal that describes this? It's sort of case 50 in a way, but not.
2 boats P/S on a beat to windward on intersecting courses which would bring them together if both boats held course and speed ... (that's not a horrible turn of phase) ..
Q: When does port fail to keep clear? A: Case 50 says it's when P scares S enough for S to take avoiding action (to steal Sandy and Ric's descriptor).
How are you describing the moment P is not keeping clear when S is turning in a direction which is not avoiding P up until they are 1 BL apart?
Created: 24-Apr-16 13:24
Diego Ravecca
Nationality: Argentina
0
The initial state was 'not in a collision course', but what happen when the boats are subject to sudden speed change because they are too light? The problem could be similar to a nose diving in a downwind high speed catamaran port/tack cross, where initial calculations are not enough taking only the course angle in the formula.
Created: 24-Apr-16 14:31
John Christman
Nationality: United States
Certifications:
Club Race Officer
National Judge
National Umpire
0
A few thoughts:
Unless the boats are sailing absolutely parallel to each other, all courses are 'converging', the course lines will cross somewhere, just a question of where. The description of a 'collision' course gives you the idea that at some point, presumably soon, the boats will be trying to occupy the same space at the same time. Adding where the contact would occur gives you a bit more context. The notion of a collision course to me says that the keep clear boat will have to take some sort of action before they reach that point.
There is a match racing call (2021.001 Question 3) that says: Rule 16.1 is a limitation on Blue to allow Yellow to continue to fulfil its requirement to keep clear when Blue changes course. Rule 16.1 can only be broken when Yellow is keeping clear before Blue changed course. In this case, Yellow was not keeping clear prior to Blue changing course; therefore, Blue did not break rule 16.1. This covers the question about rule 16 when Blue alters course and Yellow is already not keeping clear and breaking rule 10. Note that Blue could still be found to have broken rule 14.
Changing speed is not a change in course unless you change between going backwards and forwards. That is a change in the course that you are sailing. Changing speed happens all the time as boats surge, surf, or plane on waves. The keep clear boat is required to expect that a ROW boat may do that in the existing conditions. It's about the only thing in the rules where the keep clear boat is required to anticipate what the ROW might do. When boats submarine, which happens often in RC boats, and in not even that strong a breeze, the boat is generally changing course as they pivot and 'fall over'. You might be able to make an argument that they were changing course and didn't give the other boat room to keep clear. That would be an interesting case but I would hope that the rules gods would not go for that argument.
In addition to Case 147, there is also case B3 in The Call Book for Radio Sailing, that talks about a boat "unbreaking" rule 16.1. That is a very interesting case as rule 18.3 doesn't apply because P never completes her tack. But that is another thread.
Created: 24-Apr-16 18:16
P
John Allan
Certifications:
National Judge
Regional Race Officer
0
Diego Ravecca said Created: Today 14:31 'What happens when boats change speed but do not change course?'
The initial state was 'not in a collision course', but what happen when the boats are subject to sudden speed change because they are too light? The problem could be similar to a nose diving in a downwind high speed catamaran port/tack cross, where initial calculations are not enough taking only the course angle in the formula.
This discussion is all about whether B, the right of way boat, that does change course breaks RRS 16.1 and whether Y is exonerated because she is entitled to room. Whether Y breaks RRS 10 is never in question.
If the right of way boat does not change course, then RRS 16.1 does not apply at all, and, in this simple P/S crossing scenario, there is no avenue of exoneration open to the give way boat.
Created: 24-Apr-16 21:14
P
John Allan
Certifications:
National Judge
Regional Race Officer
0
Ang, 'Collision Course' and 'risk of collision'
I don't think we need to get phobic about using the phrase 'collision course', at least in discussions.
As I've said, it's quite commonly used in the Case Book.
I think the objection to using the term in FF 2 of a protest decision is that that fact is a 'scene-setting' fact, when boats may be some considerable distance apart and before the protest committee has laid out it's logical analysis of whether they are at risk of collision or contact, or not.
When we are discussing a scenario where risk of collision (in the IRPCAS sense) exists, that is if the compass bearing of an approaching vessel does not appreciably change, or in other words, 'if each boat maintains it's course and speed boats will collide', I think 'collision course' is an unobjectionable and useful term.
Created: 24-Apr-16 21:26
Gordon Davies
Nationality: Ireland
Certifications:
International Judge
0
re: "converging course", "collision course"
I believe that this debate started at an event where the jury had too much time on their hands. The fruit of these elucubrations was that the term 'collision course' was, for reasons that escape me, a conclusion. It was then decided that 'convergent course' was not a conclusion. Logically, both of these are conclusions based on the same set of facts - when boats are on non-parallel courses sailing in the direction of the intersection and the relative bearing between the two is constant. I would argue that we frequently use such conclusions - for instance stating that a boat is on port tack is a conclusion based on the facts that the side of the boat that is or, when she is head to wind, was away from the wind, is on the starboard side - except that when sailing directly downwind or by the lee her mainsail is on the starboard side. Therefore her windward side is her port side (conclusion), therefore she is on port tack (conclusion).
Created: 24-Apr-23 16:42
John Christman
Nationality: United States
Certifications:
Club Race Officer
National Judge
National Umpire
0
It is better when the sailors keep us too busy to go down these rabbits holes!
Created: 24-Apr-23 16:48
Gordon Davies
Nationality: Ireland
Certifications:
International Judge
0
John Chrisman mentioned case B3 in The Call Book for Radio Sailing, that talks about a boat "unbreaking" rule 16.1. That is a very interesting case as rule 18.3 doesn't apply because P never completes her tack. The term 'unbreaking' is not helpful. A boat may comply with RRS16.1 by changing course a second time to give the other boat room to keep clear - see, for example TR Call B4, or D3, in which a RoW boat changes course to comply with RRS15. In RS Call B3 RRS 18.3 does apply because P has passed head to wind from port to starboard and S was fetching the mark on starboard since entering the zone. However, RRS 18.3 never comes in to play in this incident, except that it means that P, who becomes inside boat, when she passes head to wind,, is not entitled to mark room. At 2 P is in a position to keep clear by tacking. As she is luffing to head to wind and passing head to wind S changes course and is now on a collision/converging course. P manoeuvres promptly in a seamanlike way by continuing to bear away. S is required to give P room to keep clear, which includes room not to touch the mark. In B3 question 3, S complies with RRS 16.1 by luffung to give P room to keep clear.
Created: 24-Apr-23 17:01
John Christman
Nationality: United States
Certifications:
Club Race Officer
National Judge
National Umpire
0
Gordon - while you might not like the term 'unbreaking', I would argue that it is appropriate. When a ROW boat alters course and is no longer giving the KC boat room to keep clear, she has broken rule 16.1 at that moment. That is what the words of the rule say. However, if the ROW boat continues to change her course and later is giving the KC boat room to keep clear then we say that she has met her obligations overall. The rule was 'broken' and then 'unbroken'.
Of course, it needs to be proven in the hearing that indeed there was a lift, that blue changed course, and that yellow would have crossed in the absence of Blue's luff.
Another way to think about this is that whenever a boat changes course she must give all the keep clear boats a way out, they have to have a way to keep clear.
I'm not sure how Appendix E fits in here. There are no rule changes there that would change this answer.
https://www.sailing.org/tools/documents/2022SupplementtoTheCaseBookFinal-[27834].pdf
Now up the Case 150.
Ang, Paul, any chance of getting those cases up on rrs,org?
DONE
We had Case 148 up already .. so just added Cases 149 and 150.
I had an old thread examining and playing with that question here ..
Of course as we course through the possibilities, we understand "course", in due course ..
A helmsperson on a beat to windward may be focusing on the state of their tell-tails and shape of her jib's luff and not realize she has "changed course" to windward/leeward as she keeps her boat "on the wind". This is especially true if there is no shoreline with clear landmarks.
Depending on the amount of weather-helm she's sailing with, a boat will change course with little or no input from the helm. In that case, it might take significant inputs from the helm [sailing the boat "off the wind"] to 'hold course'.
In my discussions with some sailors, I have found that some sailors believe that, in these P/S to windward situations, riding up a lift while holding helm is 'holding their course'.
I was in a P/S protest a while back .. I was the protestor S. I held course and had to alter to leeward to avoid 1/2 BL from P. During the hearing, P stated they saw me turn my wheel as we approached each other and asked me if I held my wheel steady or if I turned my wheel. My response was that I was holding my course on the shoreline and turning my wheel to maintain my course. Also on my boat, my wheel has an approximately 9:1 turning ratio Wheel -> Rudder. So a +/- 2 degree movement at the rudder (4 deg total) looks like a 36 deg movement of my wheel.
To someone used to sailing a tiller, that might appear to be large rudder inputs when it's actually not (depending on the wind and seas).
But the point being 'not changing course' (holding course) is often a 'deliberate action' which takes attention and intent. One sometimes cannot just stay "on the wind" and at the same time 'not change course'
What about if the PC had decided that Yellow would not have cleared Blue had both boats maintained their original courses (as indicated in positions 1)? I'm guessing Yellow broke R10 with no exoneration and Blue broke 16.1, even though Blues course change did not affect the outcome?
When we talk about PC's in this context, we talk about PC's doing 3 things...
So, following that guideline let's look at your question (which no longer aligns with your OP drawing). Let's assume the following Facts Found.
Facts Found
port[starboard] in response to a wind shift. This moved the course-intersection point forward to mid-ships on Yellow's starboard side.OK .. these are the FF's for your new scenario. Anyone want to take a stab at the Conclusions and Decision?
B is disqualified in Race n.
Comments
I don' think Angelo's FF 2, beyond saying that boats were on a collision course is relevant, and its a brave protest committee that states a point of collision with 1 foot from 2 BL out.
See Case 92
Rule 14, Avoiding Contact
Rule 16.1, Changing Course
Rule 16.2, Changing Course
When a right-of-way boat changes course, the keep-clear boat is required to act only in response to what the right-of-way boat is doing at the time, not what the right-of-way boat might do subsequently.
Stepping back:
That was needed to satisfy Johan's requested condition for scenario change. He wanted us to establish that they would have made contact if both boats held course at position 1.
John, you bring up a protest-decision writing style point which is interesting but maybe a bit off topic.
For me, I personally shy away from the phrase "collision course" in decisions because I personally feel that "collision" implies damage and also it doesn't convey where contact would have occurred.
So personally, I use "converging course" to first establish that boats are sailing toward each other. Then in a separate statement, I like describe where contact would have occurred on the boats had one/the-other/neither boat altered course from a stated distance.
It's my personal feeling that this gives an Appeals Committee or subsequent PC the ability to lay the models out or make a drawing depicting the conditions we assumed.
If you think this topic is worthy of further exploration, maybe we should open a separate thread and invite others to chime in?
But 'collision course' quite often gets a run in the Case Book.
While I wouldn't usually use the phrase in a written protest decision, I sometimes find the concept of 'risk of collision' as defined in IRPCAS useful, particularly when determining when a RRS 16 obligation starts
In determining if risk of collision exists the following considerations shall be among those taken into account:
(i) such risk shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change;
Facts Found:
I feels odd that Yellow might get exonerated just because Blue altered course. I get that Blue can't hunt Yellow, but to disregard R10 seems wrong?
In the OP scenario, Y is initially keeping clear, and B ceases to give Y room to keap clear @2-delta, as B continues to change course and there is insufficient time and space for Y to change course to windward and tack away.
In the latest example, @1, Y is only keeping clear because boats are not yet close enough for B to need to take avoiding action.
There is nothing to constrain Y from tacking away to keep clear, and if she acts promptly at this point by tacking she can keep clear.
So from the time risk of collision exists, Y has all the room in the world to tack away.
Anybody think ì should revisit my conclusions on Scenario 1B?
John, I don't think my mistake would change you writeup. IMO Blue is committed to moving forward and so needs to keep moving quickly forward by keeping her sails driving .. but maybe you want the opportunity to edit it.
Being J/105's 6kts is ~ 3m/s so a little over 3 sec per BL. A "fast tack" is 3-4 sec's. Where a tack that optimizes height and exit-speed is more like 5-6 sec's in that breeze.
So, I'd ask 2 Q's
As a thank you! to both of you, here's a treat for any PC; the OP situation in full color! I'm including it for your amusement, not necessarily to continue the discussion.
OP scenario, Y initially keeping clear by passing ahead of B, ie, not on a collision course.
B' change of course deprives Y of room to keep clear, and Y has no time to tack away. B breaks RRS 16.1 and Y is exonerated.
Last scenario, initially boats are on a collision course, Y has to do something to keep clear, there is both space and time for Y to tack away. B's change of course doe not affect the room available to Y to keep clear by tacking. B does not break RRS 16.1, Y breaks RRS 10 and is not exonerated.
The mark room to which Y is entitled us out there on her port side, and she's not sailing within it.
2 boats P/S on a beat to windward on intersecting courses which would bring them together if both boats held course and speed ... (that's not a horrible turn of phase) ..
Q: When does port fail to keep clear?
A: Case 50 says it's when P scares S enough for S to take avoiding action (to steal Sandy and Ric's descriptor).
How are you describing the moment P is not keeping clear when S is turning in a direction which is not avoiding P up until they are 1 BL apart?
Rule 16.1 is a limitation on Blue to allow Yellow to continue to fulfil its requirement to keep clear when Blue changes course. Rule 16.1 can only be broken when Yellow is keeping clear before Blue changed course. In this case, Yellow was not keeping clear prior to Blue changing course; therefore, Blue did not break rule 16.1.
This covers the question about rule 16 when Blue alters course and Yellow is already not keeping clear and breaking rule 10. Note that Blue could still be found to have broken rule 14.
If the right of way boat does not change course, then RRS 16.1 does not apply at all, and, in this simple P/S crossing scenario, there is no avenue of exoneration open to the give way boat.
I don't think we need to get phobic about using the phrase 'collision course', at least in discussions.
As I've said, it's quite commonly used in the Case Book.
I think the objection to using the term in FF 2 of a protest decision is that that fact is a 'scene-setting' fact, when boats may be some considerable distance apart and before the protest committee has laid out it's logical analysis of whether they are at risk of collision or contact, or not.
When we are discussing a scenario where risk of collision (in the IRPCAS sense) exists, that is if the compass bearing of an approaching vessel does not appreciably change, or in other words, 'if each boat maintains it's course and speed boats will collide', I think 'collision course' is an unobjectionable and useful term.
I believe that this debate started at an event where the jury had too much time on their hands. The fruit of these elucubrations was that the term 'collision course' was, for reasons that escape me, a conclusion. It was then decided that 'convergent course' was not a conclusion.
Logically, both of these are conclusions based on the same set of facts - when boats are on non-parallel courses sailing in the direction of the intersection and the relative bearing between the two is constant.
I would argue that we frequently use such conclusions - for instance stating that a boat is on port tack is a conclusion based on the facts that the side of the boat that is or, when she is head to wind, was away from the wind, is on the starboard side - except that when sailing directly downwind or by the lee her mainsail is on the starboard side. Therefore her windward side is her port side (conclusion), therefore she is on port tack (conclusion).
The term 'unbreaking' is not helpful. A boat may comply with RRS16.1 by changing course a second time to give the other boat room to keep clear - see, for example TR Call B4, or D3, in which a RoW boat changes course to comply with RRS15.
In RS Call B3 RRS 18.3 does apply because P has passed head to wind from port to starboard and S was fetching the mark on starboard since entering the zone. However, RRS 18.3 never comes in to play in this incident, except that it means that P, who becomes inside boat, when she passes head to wind,, is not entitled to mark room. At 2 P is in a position to keep clear by tacking. As she is luffing to head to wind and passing head to wind S changes course and is now on a collision/converging course. P manoeuvres promptly in a seamanlike way by continuing to bear away. S is required to give P room to keep clear, which includes room not to touch the mark. In B3 question 3, S complies with RRS 16.1 by luffung to give P room to keep clear.