Forum: Rule 18 and Room at the Mark
Giving mark room
In this scenario boats are entered the left gate zone on starbord tack, overlapped, Blue has mark room under 18.2, Yellow is ROW under R 11, and Blue is staying clear, and Yellow is required to give mark-room.
Blue claims mark room and Yellow gyps at 1 to 1,5 boats lengt from the left gate and round the right gate.
After that, if Yellow is clear ahead of Blue at the zone of the right mark,
Is Yellow is braking RRS 18.2 at the left mark ? and required to give more mark-room.
Created: 25-Jun-28 20:36
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This is interesting.
First, I will say that diagrams are great when discussing rules. Your diagram helps so much with your question. What software did you use?
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As for your question, I think it is easiest to forget about the right gate mark for the moment. Perhaps, the inclusion of the right mark rules is confusing things a bit.
So, at the left mark zone, Blue is inside/overlapped, and entitled to mark-room for the left mark. By the definition, the mark-room is to sail to the mark from her position when rule 18 turned on (position 1).
Looking at the diagram, Yellow is preventing Blue from sailing 'TO' the mark throughout. Yellow should have been giving mark-room from the moment she entered the zone (3 boat lengths from the mark). Not only at 1.5 boat lengths.
Yellow, should have borne away, sailed by-the-lee or even gybed to give Blue that room much earlier then.
Blue could have pushed her case harder, by bearing off a little. In doing so, she would have broken RRS 11, but would be exonerated by RRS 43.1(b). Even if there was contact, she would have broken RRS 14, but if there was no damage or injury, would be exonerated by RRS 43.1(c).
So in answer to your question then since Blue claimed mark-room then, "Yes! Yellow broke RRS 18.2 at the left mark. She was required to give more room."
I hope that helps. Let's see what anyone else says.
Easy tactical solution. Agree with Benjamin that the squeeze-luff in the zone breaks 18.2.
Olafur, All, I also highly recommend calling these marks "starboard' and "port" related to the rounding side (right and left get confusing depending on how you view the situation (diagram or boat).
I do not agree with Tim O'C. There is no way to get this timing right on the water. 18.2 e is specifically designed to discourage this and will be used without mercy to DSQ people who try it.
There isn't any space for error.
Blue is not in a position to "take" her room and turn down first as Blue's leeward rotation and closure towards Yellow takes away Yellow's stern-swing space. (Blue would have more control and options if Blue was bow-out on Yellow)
In this OP ... with this specific geometry ... Yellow has to move first in this scenario and her obligation is to clear a lane for Blue as soon as Yellow reaches the zone .. so that's when she has to start to maneuver to give Blue her MR.
The software for the diagram is called boats.exe and is available for free download from
http://boats.sf.net
John
Y does what is required of her and is clear ahead at pos. 4.
B could have easily rounded the left-hand mark if they had chosen to do so.
'Proper Course' is not relevant here.
So, what is “mark room course of straight to the mark”? What rule might this be?
John Ball says it clearly in the post below.
(Note, my comments will all make more sense if you use the new "Nested view")
I look at it this way. From the moment Yellow touched the zone, Blue was overlapped and entitled to mark room.
The definitions for mark room and proper course apply.
Mark-Room Room for a boat
(a) to sail to the mark when her proper course is to sail close to it,
Proper Course A course a boat would choose in order to sail the course as quickly as possible in the absence of the other boats referred to in the rule using the term.
So I imagine a corridor for Blue staring when Mark room started - and it is reasonable to say represents Blue's proper course. Yellow makes no effort to allow Blue to sail her proper course and pushed Blue out of that corridor.
John
The diagram clearly shows that she sailed "to the mark" although not perhaps in the tactical way she might have preferred.
In my opinion, Blue is TOAST!
I based my opinion largely on OP's fact, "Blue claims mark room..." I took that to read that Blue was not happy with the situation and wanted to be in a better position. When exactly, we don't know.
I also imagined the scenario at a local club regatta!! - I pictured a lot of shouting between the helms, with the inside boat becoming increasingly frustrated as they got closer to the mark. I did not picture a quiet tranquil approach like we might envisage looking at the diagram on a computer.
You essentially ask two questions.
1. When does the outside boat have to act to give room?
2. Can Outside claim as an r18 defence she was 'ready to give room' if Inside took it?
1. When does the outside boat have to act to give room?
I remember discussing many years ago whether a boat required to give mark-room should anticipate her obligation!! And here we are again. History repeats itself, eh?!
Her obligation is created by her entering the zone outside-overlapped. From this moment onwards, she must give room to the inside boat. That's what the rule says.
Equally, Inside's rights to room only start when rule 18.2 is activated.
So I think I have always concluded that Outside does not have to create the space before her obligation. She must commence doing so at the instance her obligation is activated. So when she entered the zone, she should act promptly so that the inside boat can take that room 'promptly' per the definition of room.
I prefer this rather than saying, '2 seconds'.
2. Can Outside claim as an r18 defence she was 'ready to give room' if/when Inside took it?
As for your second muse it's interesting. Again, discussed over the ages.
Rather than a case 147 concept, I take a Case 50 philosophy in favour of the inside boat.
In other words, I don't think the inside boat needs to sail in a risky way (or god forbid, make contact) in order to make her own space or prove her point.
The space should be afforded to her to sail into. In which case, Outside cannot claim, "I was watching and ready to keep clear!", if there is a chance that Inside was apprehensive whether room was going to be given.
Imagine again the scenario... Outside shouting 'no overlap', inside yelling 'overlap', hands waving wildly, hot red faces. If so, then I could say that Inside had reasonable apprehension that room was not about to be given.
Well, on the contrary, if 10 boat lengths out, Yellow calmly, in a nice voice, said, "Hey Bob. How are you doing? How's the family? Nice day out, right? Look, I can see you're inside-overlapped, so I'll give you room when you need it. I'm watching you carefully. Don't want to scratch your lovely boat. Have a good drop and rounding. Take care, buddy. See you at the bar," then perhaps.
But how often does that happen? You get what I mean.
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Tim,
The 'hard bear-away' tactic is technically sound and may work in an umpired match race, but in a club fleet race it is quite hard to nail in reality, since no one really knows where the zone is!! If I was Yellow, I wouldn't count on that kind of move working out on the water or in the protest room!
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David,
I agree with JohnB's explanation that Blue's proper course was (for diagrammatic purposes) to sail in that corridor 'to' the mark.
(OK - in real life, say with an asymmetric kite, she may have wanted to hold a little speed and then bear away for a spinnaker drop, but let's agree for the sake of discussion that at some point she wanted to sail directly to the mark. With a symmetrical spinnaker, the deeper course is even more convincing.) Its sometimes easiest to stick to worst case / 'most room' needed for discussion.
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It's possible that you're suggesting that Yellow did in the end, let Blue sail to the mark after she was clear ahead at position 4, therefore complying with 18. However, this reasoning couldn't be sensible.
Mark-room is to allow for orderly rounding of marks. It's like a 'pause / time-out' in the tactical game, to get round the mark, and restart on the other side. Yellow when required to give mark-room, cannot sensibly gain tactical advantage during that 'pause'. What's to stop her luffing Blue all the way to the edge of the zone, before gybing and claiming the same?!
No. Blue is entitled to mark-room to sail to the mark. Yellow should 'pause' her tactical game and yield the space.
Good chat folks.
But you (Bob) finished your quote from Case 75 just before the most important bit (in our situation) which says:
My 10 cents worth (ie. a dime or a a couple of pennys) goes to case 21 which says that "there is no maximum or minimum amount of space that she must give". The diagram and the commentary both suggest that B got to the mark without any silly manoeuvres and could have rounded it in a seaman-like manner if they had chosen to do so.
Case closed!
As for the rest - well, a man can dream, you know?
Most don't really understand. But when it ends up in the protest room, having made these clear calls makes a difference.
I disagree. There is nothing in this OP which implies action on Blue's part to sail outside the mark-room she is entitled to for a tactical rounding. In this case, with the boats in close proximity to each other such that Blue's path is actively restricted by RRS11 from position 1, Yellow needs to start turning down to give Blue a corridor as soon as Yellow hits the zone.
[Update] I probably shouldn't have said "Blue is TOAST!" as that suggests that B may have broken a rule which I believe she did not. I am simply suggesting that Y gave B the room required and that B has nothing to protest.
Angelo: Y didn't need to start considering MR until she hit the zone. Thereafter she needed to act "promptly" (ref: def:Room) but not necessarily 'immediately'. The OP did not describe the conditions so it is not possible to to come to a clear conclusion on this one without that context. [Update] That is, were they travelling at 1 second per boat length [s/BL] or 10 s/BL (eg. a 4m dinghy at 8kts|4m/s versus a 20m keelboat at 4kts|2m/s).
[Update] Check out cases 21 & 118.
[Update] BTW, overlapping zones - as shown in the original diagram - are a big "no-no"! So, throwing back to the OP, how can this be considered a valid situation for consideration? And then taking it to the extreme, maybe the race should have been ABN and the RO is 'TOAST' ...
syn of prompt:
in a prompt manner : without delay : very quickly or immediately
So I would say that they do need to act immediately after entering the zone. Also overlapping zones while not recommended are not a no-no. You really think that this is a case for abandoning the race and labeling the RO as TOAST?
I have no doubt that those who wrote def:Room understood the nuanced difference between the words "promptly" and "immediately". To me 'promptly' means "without unnecessary delay". On the other hand, some may consider the two words identical. I expect a lawyer would have a problem with this interpretation.
You seem to have forgotten that I mentioned "taking it to the extreme ...". In my opinion having operlapping zones only confuses the matter and derails the discussion. And while I like to see a good diagram, it seems to me that the actual distances between the boats may have been greater than what is shown. As I have mentioned before we seem to be missing a lot of the relevant 'facts' in this case.
1. Was the mark-room adequate? Was Y afforded toom to 'sail to the mark' (proven by the fact that Blue eventually got there) or should Y have given room for Blue to sail the direct route?
2. When does mark-room have to be available Is it 'immediately' - is it that the moment her hiull touches the zone, room must be there? Or 'promptly' - Y may start acting when her hill reaches the zone? How fast must she act?
3. Overlapping Zones - Are they a no-no?
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OK. I'll address the mark-room issue first.
1. Most people (including myself) have asserted that Y did not act sufficiently and mark-room was for Blue to sail the direct route (in the corridor) to a position close to the mark.
David Taylor suggested an alternative conclusion.
I rather think Dave confused the matter quite markedly in doing so, especially by stating that 'proper course has nothing to do with the matter'. We (I) couldn't work this out since 'proper course' is written there in the definition of mark-room! What could he mean?
After some lateral thought, I think I have worked out where Dave was going.
Dave touches on the fact that Blue is not entitled to make a 'tactical (a.k.a.' proper course') rounding, since Blue does not have right of way. This I agree with.
Dave's interpretation geos on to apply then, that it was not Blue's PC to sail 'close to the mark'. It was her (and every boat's) proper course to make a wide-in approach here.
At this point, we remind ourselves of the 3-part definition of mark-room.
In which case, the first part of mark room drfinition - room to sail to the mark when her proper course is to sail close to it - did not apply. So forget it.
Dave's conclusion is that the only remaining entitlements from the definition of mark-room - room to round or pass the mark on the required side, and to leave it astern.
Well, Blue indeed was given room to do those things, wasn't she?
Dave, correct me if I see this wrong.
I must admit, I have never considered this interpretation before. Now I think about it, it seems valid.
Yet, there is something about it which doesn't seem to fit comfortably. Why did many of us not assert this initially?
Let me know which way you saw this? Am I the only one?
Actually, to clarify, I agree with everything you say.
My post (before my short flight) was simply trying to re-present DavidTaylor's argument as I understood him. I thought about including my own disagreement to it (for same reasons you present) but decided not to in hope to see what people thought.
Well, landed now. Here's what I composed during the flight! I think we're on a similar page.
The problem is the condition in the definition 'when her proper course is to sail close to it'.
David discounts this provision, because as we know, any good tactician would prefer not to sail close to the mark. "Wide-in," is what they say. Thus he concludes , the condition for entitlement to sail 'to the mark' is not met.
In that world, the (a) of the definition is applied only to the approach segment of the mark-rounding process. It doesn't include the rounding part.
However, it seems that in the official interpretations, the case book at least, the sentence is consistently applied with refereence to any part of the entire rounding process.
Well, if the approach is the first half, the other half of a tactical rounding is the rounding. "Wide in, tight out" is what they actually say.
When the whole rounding is considered, at some point it is normally the boat's proper course to sail close to the mark.
(In contrast, as a test, can anyone think of a case where it is never the boats proper course to sail close to the mark? Some instances, but very few.)
So, in the official cases, the mark-room to sail close to the mark (in the direct corridor) comes into play if at some time in the rounding (without being too specific when) a boats proper course will be to sail close to it.
Case 75 describes the mark-room being the direct corridor, but also goes on to strongly hint that the boat's PC in that case was wide-in.
"That space was a direct corridor from S1 to a position close to and alongside the mark on the required side. P gave S that room."
Case 118 specifically highlights that the exact time when it was her PC to sail close to the mark was not crucial. Just that it was part of the rounding 'at some point'.
"Therefore, her proper course was to sail close to the mark at some point in her turn."
In fact, no case in the casebook describes a situation where it was not a boat's proper cours to sail close to the mark. Is that because it is essentially a given fact in any mark rounding that a boat would need to sail close to the mark... at some point?
We can apply this to OPs case.
At some point in her rounding Blue's PC would be to sail close to the mark. In which case, Blue is entitled to mark-room to promptly sail to the mark - the direct corridor. In which case, Yellow did not give that mark room.
I wonder what David's response would be.
Let's start with the question of proper course. In the definition of room 'proper course' is simply a constraint that must be met for the definition to apply. That said, it implies no particular entitlement to sail such a course.
What's the question?
I think it boils down to this: Does that first condition of mark-room apply to the phase of the rounding she is on at the time, or any part of the rounding?
I think the confusion also comes in that def: MR previously stated a boat's MR included room to pass or round as necessary to sail the course. I think people commonly replaced the phrase "as necessary to sail the course" with "proper course" in their minds. That was a mistake, as they were different.
But that said, that phrase is no longer in the rule, and the proposed inclusion of proper course in the new def: MR did not make it.
So proper course in def: MR is a "test, apply and forget" modality.
In this OP, with this specific geometry, Blue's PC is to sail close to the left gate. Therefore her MR includes room to sail to the mark on its proper side. Though we do not have updated Case 75 yet, this portion of def:MR did not change. Assuming Case 75 does not change that portion of the discussion, Blue's MR is a corridor directly to the mark from the edge of the zone to proper side of the mark.
Yellow is in a position when she reaches the zone to provide that corridor, so she needs to maneuver promptly to do so, as soon as her obligation comes into existence.
def:Mark-Room(a) is really interesting: It says "Room for a boat (a) to sail to the mark when her proper course is to sail close to it".
But what does this really mean? What does it mean to "sail to the mark"? Surely this means getting closer to the mark moment by moment ... as opposed from moving away from it. I think of this in simple geometrical terms in that we are either moving 'to' the mark or 'from' it. So, even during a 'tactical mark rounding' we are always getting closer to the mark at all times, right? It's effectively a short spiral in to the mark where we come in fat and go out thin ... also known as a Jenny Craig rounding in some circles (ie. come in fat and go out thin).
The 'corridor' concept mentioned in case 75 is interesting too. It says that it starts from position S1 but fails to deal with the fact that the opening of the corridor can really only begin once R15 turns off [ref. case 53 where I really like the "newly obligated boat" concept which is apparently implicit in R15].
My Conclusion: From the available evidence I conclude that B was never prevented from "sail[ing] to the mark" so Y did not break any rules here.
Here is the def: Mark-room in its entirety.
Please note the "and". (a), (b) and (c) are all elements of def: MR. The "when .. proper course" condition only applies to and limits the application of (a). It has no effect on (b) and (c).
It's my opinion that Case 75's "corridor" is often too broadly applied. The corridor comment is made in Case 75 about a specific boat given the specific geometry of the scenario.
That said, it just so happens that the OP has a close enough geometry to Case 75 that the corridor concept is very applicable (IMO).
I think it's a mistake to apply RRS 15 concepts to mark-room obligations. RRS 15 is only about a boat becoming ROW except then it is acquired by the other boat's action. It has nothing to do with a boat becoming obligated to give mark-room.
The physical geometry of the boats ... Yellow bow-out on Blue in such close proximity of each other ... prevents Blue from turning toward the mark to "take" her MR. The rotation of Blue's bow toward Yellow's stern and the resulting converging course would quickly lock Yellow out of any room to turn. Blue must wait for Yellow.
I also have problems with the 'corridor' concept introduced in case 75 because:
(i) the case clearly points out that the 'corridor' is not relevant to the case because the boat is ROW and is not required to follow the 'corridor';
(ii) the concept is not fully explored or explained given its lack of relevance; and
(iii) it is not mentioned in the Rules or in any other Case.
In my opinion the 'corridor' concept is half-baked at best.
On the other side, I like case 53 which says "Allowing adequate time for response, when rights and obligations change between two boats, [it] is implied in rule 15 by its requirement to allow a newly obligated boat ‘room to keep clear’." This is the way I think of it but obviously not aligned with your view.
In my world:
And specifically on R15 ...
Case 53 makes it clear that R15 applies "when rights and obligations change".
"while maneuvering promptly in a seamanlike way" is a part of "room". A ROW boat that becomes obligated to give room or mark-room to another boat, does not themselves become entitled to "room" to do so.
The only "out" for MR for an outside boat is 18.2(d) and the conditions of that rule do not apply for the OP. Other than RRS 18.2(d), there are no other "get out of jail free cards" for a boat obligated to give mark-room to another boat, if she does not do so (no exoneration under RRS 43 for breaking RRS 18 without a boat compelling her to do so). Yellow is not being compelled to break 18.
In Case 53 both boats maneuvered "immediately". That is what myself and the folks on the "DSQ Yellow" team are saying.
Yellow's obligation to provide Blue MR occurs the moment her bow reached the zone. When Yellow's bow reached the zone, Yellow did not act immediately to provide Blue a corridor to the mark.
Case 75 is applicable here. My point about Case 75 is that people misapply the corridor in situations where the boats are not close to each other. Yellow and Blue are close enough to be limiting each others maneuverability ... therefore Case 75's corridor is very applicable.
I agree that the wording in some of the cases is "unfortunate and confusion-generating" as you note. Some 'rules' in the RRS could also be similarly described. This is most unfortunate but it is our world today :-(
Personally, I believe that Case 53 makes sense and is really important here.
As I have previously proposed:
Is this not how the rules should be applied in our sport?
Thank you for that comment. IMO it's not only that. It's easy to find places where people are expressing divergent views ... but the level of camaraderie, patience and respectful dialog here ... I really think is unmatched ... which says a lot about our forum members.
Were the Roos Robbed in Portsmouth? We discuss the Race 6 Penalty with SailGP's Chief Umpire: T4:45
AUS is outside GBR and required to give room to GBR.
Mitchell explains how they expect the boat required to give room to proactively act to give room first - rather than the boat entitled to room making the first move.
(Let's not get into a discussion on the incident. It's the room principal, I'm highlighting.)
Similarly, when entering the zone, the outside boat can't rely on a defence that 'they were waiting for the inside boat to take the room'. The outside boat should be making the room first.
(See my discussion earlier in this thread: "2. Can Outside claim as an r18 defence she was 'ready to give room' if/when Inside took it?")
But as you say, it's only slight connected to our situation particularly given that it specifically relates to rule 19 (and 15?) whereas here we are dealing with rule 18 and (possibly) 15.
I also note that Craig (the chief umpire) mentions that anticipation is not required under the rules but that he also mentions there are special considerations involved in high speed sailing. So are we talking here about grandpa driving his Volvo to church on Sundays or an F1 driver racing in a Grand Prix. I like to think that the Racing Rules of Sailing apply to the majority of us who sit somewhere in the reasonable middle of this spectrum but not close to either end of it.
My view is:
We can all argue the toss, but the umpires decision should be final and we all need to accept it :-)
BTW, I'd love to be a fly on the wall at the next 'teams debrief'.
Dare we say that, at least in SailGP, a boat must "anticipate"? (.. and once the word was uttered ... it began raining frogs)
So, does that change anyone's position?
I am far from the most experienced judge here but I do feel vindicated and perhaps a little emboldened ;-)
Even without that wording, I don't see any other obvious interpretation of RRS 18. It includes "Room to sail to the mark". That includes space to maneuver promptly and in a seamanlike way. Given Blue's approach here, I don't know if anyone would argue that they could round that starboard mark in a seamanlike way given the room they have received.
2021-2024 CASE 75
The mark-room that P was required to give S was the space S needed in the existing conditions to sail promptly to the mark in a seamanlike way.
That space was a direct corridor from S1 to a position close to and alongside the mark on the required side. P gave S that room. However, because S had right of way she was not required to remain within that corridor; she was permitted to sail any course provided that she complied with rules 16.1 and 18.4.
2025-2028 CASE 75The mark-room that P was required to give S was the space S needed in the existing conditions to sail promptly in a seamanlike way to the mark (see Case 118). P gave S that room. However, because S had right of way she was permitted to sail any course provided that she complied with rules 16.1 and 18.4.
The sentence "That space was a direct corridor from S1 to a position close to and alongside the mark on the required side." was removed.
The phrase "she was not required to remain within that corridor;" was also removed.
Let's all be clear that these two changes mean that the word 'corridor' no longer exists anywhere in The CaseBook or ni the RRS.
BTW, the phrase "permitted to sail any course provided that she complied with rules 16.1 and 18.4." is the same in both CaseBooks. So, when a boat acquires mark room she may sail an course but she is still required under 16.1 to give the other boat room to keep clear.
The drawing is such that we might need more FF's to determine if Blue was given room to sail to the mark (which gives her the right to the space required to sail promptly to it).
The reason I say we'd maybe need more FF's is by flipping the question a bit.
Let's say ...
Is Blue exonerated under 43.1(b)?
I would say yes. She is sailing in the room she is entitled to.
PS: Which goes back to the additional FF's. We don't want boats to think that they need to have contact with each other just to prove their point.
It seems to me that blue tried to play the rules and lost by playing a bad tactical game.
And you are absolutely right Angelo, there are other FFs that we need to make a reasonable decision on this one.
Could you give us one or two examples where you think that the direct corridor was not applicable?
To me, it really only has meaning when the boats are close enough to effect each other's course. Misapplying the corridor in inappropriate scenarios can lead people to determine that MR has a "use or or loose it" quality.
Take Case 12 for instance. At position 1, OL enters the zone ... but the boats don't engage each other until just before position #4. At that point they close enough to effect each other and be engaged by the rules. Talking about the corridor at position 1+ doesn't inform anything.
In addition, there is another thread somewhere (if someone can find it that'd be helpful) where John Christman and I were on the same page in how we were talking about it. There were lots of examples as I recall in there.
Thoughts on how this has clarified or otherwise?
I think we ended by trying stress, "Don't consider that as anything more that thinking out loud. Wait for the Casebook."
Anyway, whatever was said or the best, I think the Casebook is pointing to a 'corridor' - but with a more standard phraseology. (I'm not as alarmed by the change in Case 75 as everyone seems to be.)
Let's consider Case 75 flipped
B, on port does not keep clear of Y on starboard. B breaks RRS 10 and 14.
With the 'corridor' approach, B is way outside her corridor, Y is giving B all the room in the world to sail in the corridor, B is not sailing within the mark-room to which she is entitled and is not exonerated for breaking RRS 10 and 14. If Y breaks RRS 14, because she is the right-of-way boat and there is no injury or damage she is exonerated, and she breaks no other rule.
With the 'dynamic' approach, we have to determine when B 'engages' with Y (or use whatever other language you like for 'engages', 'affecting her course' maybe?). I'd say that was round about @2.5. That would be shown by the black line.
EDIT: fixed diagram, Thanks Angelo, Y remains on Stbd, steady course throughout.
In this case, I think that B has still got outside the room to which she is entitled and is not exonerated
In contrast to the 'corridor' approach, this is much more 'rubbery' and I'm not too comfortable with it.
If the Case Working Group was going to knock out the Direct Corridor reference, then It would have been helpful if they had provided a positive example.
Note, that while Case 118 defines the boundary between sailing to the mark and rounding the mark, as 'when the mark is abeam of her bow and she is close to and on the required side of the mark', it is about rounding the mark, not sailing to the mark.
Agree.
But this aspect of mark room is unclear to me.
Is it a reasonable statement that in my left hand sketch the green shading is a reasonable representation of the mark room that a boat at position 1 is entitled to?
And I think there's consensus that there is no requirement for her to sail that track if she can do so without breaking other rules.
In the second two sketches we seem to have consensus that the 2A/2B is not sailing within her entitlement to mark room.
One interpretation, shown in the middle sketch, especially from the old case wording, is that the 'corridor' is fixed, and even though the 3A has turned down and is now sailing to the mark, she is still outside the original corridor and thus outside her mark room.
The other alternative, in the right hand sketch, is that mark room is always available from where a boat is, so that there is a new 'corridor' of room from 2B's position, so 3B is now sailing within her mark room.
My impression is that by removing the word corridor, which has implications of something fixed and unmoving, the revised case is more in lines of the 2B/3B sketch.
On the other hand, if the intention is that a boat sailing to the mark has mark room, and one not sailing to the mark does not, would it be clearer to say so in the rule or a case?
I must admit, I think this word 'corridor' and its removal, is being a little over-thought. I think the Casebook is still suggesting the middle diagram (2A/3A) and that is still to old-school nerds, a corridor.
Case 118 clarifies that room is "the space to sail promptly in a seamanlike way to the mark".
The word 'promptly' is defining. The phrasing must be interpreted to mean 'promptly after the moment mark-room is owed'. Thus, the boat entitled to mark-room would not be exonerated if she dilly-dallied and aimlessly (unseamanlikely) wandered about the zone on her way to the mark - and broke a rule.
I don't think the removal of the term 'corridor' is such a big change as being made out.
'The space to sail promptly to the mark from the boat's position at the moment mark-room is owed' defines a pathway from the boat directly to a position close to the mark with no unseamanlike deviation from that route. The width of the path is 1 boat width (+ a little extra only to allow for the non-expertise ability of the crew).
I think this geographical pathway could still be described as a called "a corridor" - as in your diagrams. We often use analogies to help explain rules in a 'language' which non-nerds may be able to relate to.
The Casebook writers probably simply wanted to standardise the phraseology and leave analogies to us on the educational shop floor.
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I think the key question is; if Blue was to bear away and sail to the mark and there was contact would you exonerate Blue because she was sailing within the mark room to which she was entitled, or DSQ her under rule 11?
DSQ Blue for rule 10/11 and 14. Not exonerated.
I think this problem arises from some people having a misconception that a boat entitled to mark-room is required to keep within that mark-room.
We know that that's plain not right.
Obviously, the rectangle represents the corridor from where B entered the zone to the mark.
In this case, @2.5, the boats are more widely separated and arguably have not yet engaged. I think that point comes a bit later, about @2.8, and the Black line again, shows B's course to the mark from that point.
In this case, it is far less clear that B is outside her mark-room. By the diagram, I'd say that she is just outside, but with conflicting evidence in a protest hearing it would be very hard to resolve.
Now let's consider Jim's diagrams.
First, the 'corridor' never went any further than a position 'close to and alongside the mark': there's no corridor past the mark. I think mark-room with a corridor is more like a frying pan, or an inverted comma. So the corridor isn't L shaped.
Just playing with language, in Jim's 2A and 2B positions, the boat is sailing away from the mark, so, pretty clearly she's not sailing to the mark, and isn't in her mark-room.
Jim and Ben: Nothing in Case 75 ever said that the corridor was narrow. Maybe 1 boat width, plus a little bit, maybe 2 boat widths would be better. What about a boat sailing along with her inside gunwale just inside the boundary of the corridor? Once again, if you're going to get down to feet and inches, you're going to have massive evidential difficulties in a hearing.
Ben
Gosh yes. Firstly Mark room ends when the mark is left astern, presumably only about a boat's length past the mark, and secondly, if I read correctly, there seems to be no restriction on the course a boat may take. No requirement to be on the rhumb line, a proper course or anything, just to be leaving the mark behind.
And at position 2 when B reaches the zone they are not that far apart, maybe one boat length more than in the Case 75 diagram.
Facts
Two boats, S and P, were sailing directly downwind towards a leeward mark to be left to starboard. They had been overlapped for several lengths with P inside and slightly ahead. As P entered the zone, she luffed. As her bow came abreast of the mark she bore away to gybe, and there was contact, but no damage or injury. S protested P under rule 10 while P protested S under rule 18.
Decision
Existing conditions may increase or decrease the time/distance.
Added note:
The keep clear boat entitled to mark-room does not have to remain in that 'corridor'. She can sail outside that corridor if she wants, but if she breaks a rule, she is not protected - so no exoneration.
I go back to the first facts in Case 75 ... (note: drawing shows both boats flying symmetrical spins)
The facts establish that the boats in Case 75 can sail directly DW to the mark. In this instance the space is a direct corridor directly downwind.
Here is my question ..
This would allow all the other factors to come into play that allow us to define that space .. without us jumping to drawing 2 straight parallel lines to the mark in our minds.
Factors..
Let's look at John's last drawing. I agree with him here that depending on all the items above Blue may or may not be sailing within her room because we do not know their speed or how they get through a gybe ... wind .. sea-state, etc.
Looking at the moment of a rule-breach by the room-entitled boat (that may/may-not be exonerated under RRS 43.1(b)) ... ask the question:
We factor in all the elements above ... then if answer is:
PS: Asking and answering this question comes to the same outcome of Case 75 both regular and flipped.
That does seem to be a rather good rule of thumb for a PC.
1. Did the boat entitled to Mark Room break a rule?
2. Did she have enough room given to avoid breaking that rule?
perhaps a third question:
3. Was she sailing directly to the mark?
I think the problem is something to do with the fact that the primary function of mark-room is room to sail to the mark with protection for limited (Section A, 15, 16, 31) breaches, not room to avoid breaking all Part2/31 with possible getting to the mark.
Jim - why not just have Q1 and 3?
That said ... I haven't thought of a circumstance in which my Q doesn't work.
Let's try to break it.
Regarding your Q3 .. my point is that sailing directly to the mark is not part of def: mark-room ... the word "directly" is not part of the rule. A boat often needs to sail a path not directly to the mark to sail to the mark for a variety of reason (which I listed some).
BTW .. If you ever receive a private email from me, you'll see my signature block on the bottom ..
;-P