Not seeing a big difference here.
But what about 18.4 being turned off?
An inside boat, having been given room to round, need no longer gybe to her proper course!

Could be a gate mark

I do not understand the reference to 18.2(F) it seems inapplicable in the current rules.
I do not understand the reference to "Proper course" this has no relevance to "Room" except in Match Racing.
 when Mark room has been given 18 is off so there is no new 18.1(a). for a boat jumping in.
Mark room currently has been given when:-
A boats proper course no longer takes the boat to the mark.
The boat has room to round the mark.

Thanks Mike,
I should have referred to 18.2(c)(2).This requires a boat that obtains an inside overlap, as per my diagram, gives the boat entitled to  mark-room room  to sail her proper course while they remain overlapped. My point is that if 18 no longer applies then nor does 18.2(c)(2) or for that matter  18.4 as mentioned by Philip. My concern is not with the current rules, but how we decide mark-room has been given and 18 turns off in the new rules, when that room has not been taken and the boats have not necessarily passed the mark on the way to the next mark assuming it is upwind in my diagram.
 In my diagram I believe Blue will infringe under the current rules but will not under the new rules.
 I am happy to be persuaded differently!

I do see the reference now.
I still do not see the infringement now or under the next rule and neither did you when I looked at the original post.
Assuming (as she bore off later) she had to go above her proper course at 5 (yellow) she was outside the mark-room she was entitled to and with 16.1 not entitled to force the other boat onto the mark.
I did try to cover when mark-room had been given.
Somewhere between 3 and 4 yellow passed the point when if she headed up to a closehauled course she would pass close by the mark. As she passed that point she had been given mark-room.
As I see it up to that point she is always able to change course (especially if R O W) to claim her mark-room.

John, Rob O hinted that this was coming during the analysis of this scenario/thread (not too diff from yours).

 https://www.racingrulesofsailing.org/posts/274-contradiction-in-rule-18

Rob’s post (inc history and background) is near the bottom. 

Thanks Ang,
The change to 18 does resolve the situation covered in your link as in my scenario Blue  will  not  get mark-room under 18.2(a). 
There does appear to be some agreement that mark-room has been given by Blue somewhere between positions 3 and 4
I think this may now create a scenario  that encourages Blue to have a go for the gap that is currently discouraged by 18.2(c)(2) but will not be discouraged next year as 18 will not apply if it can be argued room has been given..  
If Blue can get her nose in Yellow will be governed by 16 when 18 turns off so she will not be able to close the door. Not sure yet if this is good or bad and maybe, as others have said, it may not be any different except that the discussion will soon be about whether mark room has been given and not if a boat has room to sail her proper course!
I do find the change made in appendix C2.9 gives a clear cut off.  Yellow would be entitled to mark-room in my scenario as the mark is not astern of her. There must be some reason why this has not been introduced for fleet racing.
This would also resolve Philip's 18.4 issue as Yellow would likely not be on the next leg so 18 would still apply.
The continuing joys of rule 18!!!

When the boat entitled to mark-room has been given that mark-room, 18.2(c)(2) ceases to apply also under the current rules, according 18.2(d). So, i see no difference between old and new rules about this.

Of course, since there is a change in definition mark - room, that affects some of Rule 18 scenarios. The way I see it, under the new rules, a boat entitled to mark-room is always entitled to room until the mark is astern of her, regardless of the direction of the next mark.

In the meanwhile, since the new definition explicitly states that mark room includes room for a boat to pass the mark as necessary to “sail the course”, thus to pass the mark on the required side, I see no reason why the definition keeps reffering also to room to leave a mark on the required side. I believe it is an unnecessery repetition to an already complicated rule.

Furthermore, according the new wording of 18.1, I find it also frustrating. 

Thus, in a Rule 18.3 situation, since Rule 18 will no longer apply between boats when the boat entitled to mark-room, under 18.3, has been given that mark-room, we have to assume that seases also the obligation of the boat that passed head to wind from port to starboard tack in the zone of a mark to be left to port, not to cause a boat that has been on starboard tack since entering the zone to sail above close-hauled to avoid contact. An obligation which is however irrelevant to the obligation to give that boat mark-room, if she becomes overlapped inside her.

 

Also, we have to assume that when a boat entitled to mark-room has been given that mark-room, will sease also the obligation of the inside overlapped right-of-way boat who must gybe at a mark to sail her proper course, not to sail farther from the mark than needed to sail that course until she gybes. 

Was that the intention of the rule makers?

 

In Submisssion 131-19 the US proposed to re-define mark room:
"The addition of the words 'and her course is no longer influenced by it'
at the end of Mark-Room (b) extends the application of mark-room 
beyond the point where the boat has completed passing the mark for 
those situations when she continues to need the protection of rule 18"
[for drift, etc.].
This would also have solved the 18.4 issue, since the position of the mark
would continue to influence her with a gybe obligation, even if she had 
physically passed the mark.
That US proposal was not adopted by WS, however.

I do not agree about the mark being astern of her. This may be a match race norm but there is nothing to add it to fleet racing.
If in this scenario the yellow boat is sufficiently to leeward I believe she has had mark room even when the mark is not astern.

The last sentence of rule 18.1 is simply a clarification of a principle that has been around forever:  if a boat is entitled to room to do something, her rights under that entitlement go away after the maneuver is completed.  Both John and Mike are saying, in effect, if a boat entitled to mark-room dilly-dallies while taking it, she "has been given that room" as soon as the time arrives when she could have gone around the mark; but common sense and new rule 18.1 say no, she has been given the room when the maneuver has been completed, in this case, when she has passed the mark, leaving it on the required side.  

There are good reasons for not using John and Mike's interpretation -- consider, for example, a boat that enters the zone of a leeward mark clear ahead and then drops her spinnaker into the water.  She comes to a dead stop while retrieving her chute.  Suppose a boat comes in to that mark a minute later.  Can they claim the "gave her mark-room" and therefore she no longer is entitled to that room?  Surely not.  

John and Mike's interpretation might even prevent the normal "wide and then tight" rounding, as that surely takes longer than a tight seamanlike rounding.  John's original diagram shows Yellow dropping well down below the mark, but suppose she had simply started her turn two lengths or so away from the mark?  Could Blue than "go in" and claim she had given Yellow mark-room and therefore rule 18 no longer applies when yellow "closes the door"?  Surely not.

I see nothing in the new wording that changes the application of Case 63.
Yellow left room and Blue takes that room at her own risk.
Mark room for Yellow has ended after P4 as her proper course is no longer close to the mark. Yellow as ROW may luff up above close hauled after P5 but is subject to R 16.1. 
John

Rob, 
I may be required to give you something but I cannot force you to use it. After I have given it I have fulfilled my part of the bargain.

I do not read the new wording of 18 to imply that the rule applies until the manoeuvre has been completed. It states that 18 no longer applies between boats when mark room has been given. 

The definition requires a boat gives:

Room to sail to the mark – Given in my scenario

Room to pass the mark as necessary to sail the course without touching it. – given in my scenario.

I think Blue has complied with all the requirements by position 3½ so all of 18 turns off.

This may not be a desirable interpretation, but it is nevertheless an interpretation. 

My intention when starting this post was to clarify my understanding and come up with a way to explain the new wording and reasoning to sailors in a way that gives a consistent and correct interpretation.

 I am not yet there! 

Rob
I think you have misrepresented my position.
Under what I said, 18 would be on in each of your scenarios.
I said if you sailed so far from the mark that if when you headed up you could not pass close to it because you had effectively left say 3/4 length to the mark (enough for another boat) you had been given mark room.
This does not stop wide out close in as you pass close to the mark.
I do not see the problem.

Mike, you're right, and I misunderstood your response.  I apologize. I agree completely with what you say. 

John,  I agree that the distinction between "has been given" and "has taken" is a problem, and the alternative interpretation you give is legitimate in terms of language.  However, it is definitely not the interpretation intended, and, as I wrote in my earlier response, is not a practical interpretation because in many cases it's impossible to determine when exactly a boat has given sufficient room if the other boat hasn't yet taken it.  In your diagram, it seems to me that if Yellow were to try to close the door on Blue at position 6 she would have to sail above her proper course, but in your discussion you indicate that you are addressing a scenario where, were Yellow to luff to "pinch mode", Blue would break rules 11 and 18.2.  I believe that in such a scenario the game has not changed.  The way I plan to teach this is:  When Yellow luffs to a proper course and gets fouled by Blue, Yellow is sailing within the room to which she is entitled (see rule 18.2(c)(2)) and therefore is exonerated under rule 43.  If Blue argues that she gave Yellow mark-room, Yellow's response is, clearly not, as we were taking that mark-room when you fouled us.  

I think that introducing an alternative interpretation of rule 18.1 would not be helpful in presenting the rules to sailors, even if that interpretation is semantically correct..  

Thanks Rob,

I have no problems with what you say but I think we all cringe a bit when we have to say or are told ‘that’s not what we intended’. I would still find some difficulty in a hearing justifying that mark room had not been given at position 3.5. 

I think it could change the game as, after 18 is off, Yellow becomes subject to rule 16 and if Blue is able to get her bow to the mark before she interferes with Yellow then I think Yellow would have to give room for Blue to avoid the mark as it is not seamanlike for Yellow to force Blue into the mark.

As you are aware, I have been involved in writing/developing rules in the past and I appreciate it is not easy but I have never liked rules that have more than one valid interpretation – even if one of them is undesirable.

Sailors and judges need certainty and something that can be applied consistently. I do not think it has been achieved on this occasion. 

The new wording in C2.9 is clear. Rule 18 no longer applies between boats when the boat entitled to mark-room is on the next leg and the mark is astern of her.

Applying this to my scenario there is no doubt that Yellow is entitled to mark room throughout. 
I must admit that I have yet to analyse the ‘what ifs’ when more that two boats are involved but my initial thoughts are that this is far easier to explain and understand than the ‘when room has been given’ statement.

I would be interested to know the reason why this would not work in fleet racing.

 

There doesn’t seem to have been any consideration in this string re the definition of Mark Room, which together with the word “given” may add a temporal limit to the right to exoneration. Case 21 may also be relevant: “The phrase ‘manoeuvring promptly in a seamanlike way’ ... addresses the inside boat, saying she is not entitled to complain of insufficient space if she fails to execute with reasonable efficiency the handling of her helm, sheets and sails while manoeuvring”.  Does this add weight to John’s concerns?