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Sam.Spoons View Drop Down
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 20 at 10:03pm
Originally posted by JimC

Like a lot of these angels dancing on a pin questions I suspect the answer is simpler than its portrayed.
The only time the inside boat doesn't get mark room is if one boat was clear ahead when she reached the zone. Yes, the zone magically expands when the longer boat overtakes the shorter boat. But so what. The boats are overlapped. The shorter boat reached the zone when the longer boat got closer to the mark.

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Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 20 at 10:49pm
Originally posted by JimC

.
The only time the inside boat doesn't get mark room is if one boat was clear ahead when she reached the zone.
Not quite right.

If boats were overlapped when the first of them reached the zone, the boat inside at that time is entitled to mark-room and continues to be entitled to mark-room even if later the overlap is broken or a new overlap begins (rule 18.2c(1)).  That's the very nature of rule 18.2b 'enduring' mark-room.

But the question we have to answer here is whether boats were overlapped when 'the first of them reached the zone'.

Originally posted by JimC

 Yes, the zone magically expands when the longer boat overtakes the shorter boat. But so what. The boats are overlapped. The shorter boat reached the zone when the longer boat got closer to the mark.

'Overtakes' is not a word used in the rules? <g>

I don't agree that the Opti 'reached' the newly defined zone at the instant the NP got bow out on her:  Arguably, the Opti had already reached that zone some time before.

My inclination is to say that neither boat was clear ahead when she reached the zone, and boats were not overlapped when the first of them 'reached' the zone:  rule 18.2b does not apply, but boats are overlapped in the zone therefore rule 18.2a does apply and whoever is inside is entitled to mark-room.

That is to say, firstly, whoever is overlapped inside initially, is entitled to mark-room but if the overlap is broken, mark-room goes off, and is a new overlap subsequently begins, whoever is overlapped inside on the new overlap then gets mark-room.  I would have thought that once the NP got her bow in front of the Opti it would be
  • very unlikely for the Opti, initially overlapped outside, to ever get around the NP into an inside berth because the starting point, surely is that the NP is going faster because she is carrying way and has the taller rig and the Opti wouldn't be able to accelerate and get around the NP?
  • unlikely that the the Opti, initially overlapped inside will either have the acceleration to draw clear ahead of the NP, or, if she falls behind, can then accelerate outside the NP.
Otherwise I don't think this interpretation is problematical.

From the Opti's POV, while she is bow out, she knows that she has not reached her zone and isn't entitled to mark-room, so at the instant the NP gets bow out, the Opti shouldn't have been expecting to have mark-room.

If the Opti had an ounce of sense, she'll be defending her wind like crazy, because if the NP gets over the top of her, she's going to die the death, so arguably if she lets the NP inside her, she's got nobody but herself to blame.
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 20 at 10:15am
I think you're uncharacteristically counting angels mate, but I don't mind having a go.
Yes, I was being a bit sloppy. The zone doesn't change when one overtakes the other, it changes when one is closer to the mark than the other, but it matters not, they are overlapped, and the rules don't distinguish between overlapped A slightly ahead and overlapped B slightly ahead anyway.

So when does a boat reach the zone? Now, I submit that there is no definition of reaching the zone, the definitions states a boat is in the zone or not, and she's in the zone when any part of her hull is in it.



So, in the L diagram the zone is the blue circle. No boat is in the zone, so no boat has reached it. In the R diagram a second later the orange zone applies, both boats are in the zone, so both boats have reached it. So that's the point at which clear ahead, clear astern applies. They reached the zone when the zone expanded.

If you really want to dance on pins, if you consider boats gybing downwind that must gybe to make the mark, then it is possible to imagine blue being clear ahead and entitles to mark room when orange becomes closer to the mark and the boats have reached the newly expanded zone.



But really, its not any different from any other situation where a boat clear ahead is further from the mark. The fact that the zone expanded doesn't seem to me to change anything.

Actually the more complicated situation, it seems to me, is if the shorter boat becomes nearer to the mark, and the zone contracts such that neither boat is in the zone. But in practice that's still pin dancing, because if the boats are overlapped there isn't a problem, and if they are not overlapped there probably still isn't a problem, and in any case there's always 18.2.e

Edited by JimC - 12 Jan 20 at 10:49am
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 20 at 10:45am
From what I can work out, in practice it actually doesn't matter. Even with my Moth/Rater scenario where the Moth would be, potentially, quite capable of accelerating past the Rater. I can't think of a situation where the change in the size of the zone would change the rights/obligations of the two boats.
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Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 20 at 11:12am
Reminded me of an incident some years ago on Lake Garda, Oppi race going on, when a fleet of performance sail boats steamed through middle of Oppi race. Vaguely recall performance boats were German.
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 20 at 3:53pm
Just a related thought, new rules next year and somebody mentioned that they had seen a reference to changing the overlap/finishing requirement to be hull only rather than, as at present, hull and appendages. I haven't come across anything like it but does anybody know if there is going to be a change?

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Post Options Post Options   Quote jeffers Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 20 at 4:02pm
Originally posted by Sam.Spoons

Just a related thought, new rules next year and somebody mentioned that they had seen a reference to changing the overlap/finishing requirement to be hull only rather than, as at present, hull and appendages. I haven't come across anything like it but does anybody know if there is going to be a change?


I doubt we will know much until June time when the new rules are usually released. Unless someone from the rules panel fancies giving us a preview.
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Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 20 at 8:33pm
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 20 at 9:54pm
So it does appear they are going to change the 'overlap' def to hull only. Should discourage assy boats from barging in at a leeward mark  LOL

Interesting that Windsurfers don't have a zone at all, seems like a bargers charter to me.....
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Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 20 at 10:00pm


Originally posted by JimC

I think you're uncharacteristically counting angels mate,

I hope you are saying I'm usually practically minded.  If so, thanks.

but I don't mind having a go.

And I'll try answering you.  I'm inclined to agree that this is real angels dancing stuff, with some semantic and geometrical sophistication that I'm not sure I'm in command of, and I'm not sure the rules contemplated.

Yes, I was being a bit sloppy. The zone doesn't change when one overtakes the other, it changes when one is closer to the mark than the other, but it matters not, they are overlapped, and the rules don't distinguish between overlapped A slightly ahead and overlapped B slightly ahead anyway. 
Yup.
So when does a boat reach the zone?
Agree that's the key question.
Now, I submit that there is no definition of reaching the zone, the definitions states a boat is in the zone or not, and she's in the zone when any part of her hull is in it. 
Agreed.


So, in the L diagram the zone is the blue circle. No boat is in the zone, so no boat has reached it.
Agree.
In the R diagram a second later the orange zone applies, both boats are in the zone,
Agree
 so both boats have reached it. So that's the point at which clear ahead, clear astern applies. They reached the zone when the zone expanded. 
Here's where the semantics and geometry kick in.
I would say that a boat 'reaches' the zone when the point on the boat nearest the mark is neither inside nor outside the zone.  Consider the tangent to a circle.
I would say that because of the instantaneous 'expansion' of the zone, this point never occurs.  At one instant Orange is no nearer the mark than Blue, and (by last point of certainty), Blue defines the zone (and neither is in it), the very next instant, Orange is bow out and Orange defines the zone, and both are in it.  The point of 'reaching' the zone has never occurred.
I really don't feel competent to take the argument any further than that.  If a Case came out (which is unlikely because the situation is so artificial, and because at least rule 18.2a will apply and will work uniformly most of the time), that said the opposite, I wouldn't be at all upset.
If you really want to dance on pins, if you consider boats gybing downwind that must gybe to make the mark, then it is possible to imagine blue being clear ahead and entitles to mark room when orange becomes closer to the mark and the boats have reached the newly expanded zone. 
Disagree.  When a clear astern boat reaches the zone first, rule 18.2b does not apply and rule 18.2a does.  And that's what I've been saying.
<blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;">
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<div ="row"="" style="-sizing: border-; margin-right: -15px; margin-left: -15px; color: rgb51, 51, 51; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; : rgb255, 255, 255; font-weight: bold; margin-bottom: 10px;"><div ="col-sm-2="" -xs="" nowrap="" text-right"="" style="-sizing: border-; text-align: right; : relative; min-height: 1px; padding-right: 15px; padding-left: 15px; : left; width: 211.438px; white-space: nowrap !imant;"> 
<div ="row"="" style="-sizing: border-; margin-right: -15px; margin-left: -15px; color: rgb51, 51, 51; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; : rgb255, 255, 255; font-weight: bold; margin-bottom: 10px;"><div ="col-sm-2="" -xs="" nowrap="" text-right"="" style="-sizing: border-; text-align: right; : relative; min-height: 1px; padding-right: 15px; padding-left: 15px; : left; width: 211.438px; white-space: nowrap !imant;"><span ="glyphicon="" glyphicon-plus"="" style="-sizing: border-; : relative; top: 1px; display: inline-block; font-family: "Glyphicons Halflings"; line-height: 1; -webkit-font-smoothing: antialiased;"></span>
<div ="col-sm-12="" mb10"="" style="-sizing: border-; : relative; min-height: 1px; padding-right: 15px; padding-left: 15px; : left; width: 1238.66px; color: rgb51, 51, 51; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; : rgb255, 255, 255; margin-bottom: 10px !imant;"><b style="-sizing: border-;"><div ="trix-"="" style="-sizing: border-; line-height: 1.5;"><div style="-sizing: border-;">Rule <a ="rule-popover"="0" -trigger="manual" -placement="auto" -="true" -title="Rule: 12" data-url="/rules/643?xformat=fleet" style="box-sizing: border-box; background-color: transparent; color: rgb(51, 122, 183);">12</a>, On the Same Tack, Not Overlapped 
<div ="col-sm-12="" mb10"="" style="-sizing: border-; : relative; min-height: 1px; padding-right: 15px; padding-left: 15px; : left; width: 1238.66px; color: rgb51, 51, 51; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; : rgb255, 255, 255; margin-bottom: 10px !imant;"><b style="-sizing: border-;"><div ="trix-"="" style="-sizing: border-; line-height: 1.5;"><div style="-sizing: border-;">Rule <a ="rule-popover"="0" -trigger="manual" -placement="auto" -="true" -title="Rule: 14" data-url="/rules/879?xformat=fleet" style="box-sizing: border-box; background-color: transparent; color: rgb(51, 122, 183);">14</a>, Avoiding Contact 
<div ="col-sm-12="" mb10"="" style="-sizing: border-; : relative; min-height: 1px; padding-right: 15px; padding-left: 15px; : left; width: 1238.66px; color: rgb51, 51, 51; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; : rgb255, 255, 255; margin-bottom: 10px !imant;"><b style="-sizing: border-;"><div ="trix-"="" style="-sizing: border-; line-height: 1.5;"><div style="-sizing: border-;">Rule <a ="rule-popover"="0" -trigger="manual" -placement="auto" -="true" -title="Rule: 15" data-url="/rules/878?xformat=fleet" style="box-sizing: border-box; background-color: transparent; color: rgb(51, 122, 183);">15</a>, Acquiring Right of Way
<div ="col-sm-12="" mb10"="" style="-sizing: border-; : relative; min-height: 1px; padding-right: 15px; padding-left: 15px; : left; width: 1238.66px; color: rgb51, 51, 51; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; : rgb255, 255, 255; margin-bottom: 10px !imant;"><b style="-sizing: border-;"><div ="trix-"="" style="-sizing: border-; line-height: 1.5;"><div style="-sizing: border-;">Rule <a ="rule-popover"="0" -trigger="manual" -placement="auto" -="true" -title="Rule: 18.2" data-url="/rules/682?xformat=fleet" style="box-sizing: border-box; background-color: transparent; color: rgb(51, 122, 183);">18.2</a>(a) & (b), Mark-Room: Giving Mark-Room
<div ="col-sm-12="" case-index-abstract"="" style="-sizing: border-; : relative; min-height: 1px; padding-right: 15px; padding-left: 15px; : left; width: 1238.66px; font-style: italic; margin-bottom: 10px; color: rgb51, 51, 51; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; : rgb255, 255, 255;"><span style="-sizing: border-;"><div ="trix-"="" style="-sizing: border-; line-height: 1.5;"><div style="-sizing: border-;"><i style="-sizing: border-;">If the first of two boats to reach the zone is clear astern when she reaches it and if later the boats are overlapped when the other boat reaches the zone, rule 18.2(a), and not rule 18.2(b), applies. Rule 18.2(a) applies only while boats are overlapped and at least one of them is in the zone.
</span>
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But really, its not any different from any other situation where a boat clear ahead is further from the mark. The fact that the zone expanded doesn't seem to me to change anything.

Actually the more complicated situation, it seems to me, is if the shorter boat becomes nearer to the mark, and the zone contracts such that neither boat is in the zone.
That's Sam's foiling Moth scenario.
In that case, I think, Orange, the longer boat reaches 'her' zone first, ahead of Blue, the smaller foiler, and rule 18.2b clicks on, without a doubt.  When Blue travelling faster, becomes nearer the mark, it might be thought that the zone 'contracts', but I think the 'thereafter' in rule 18.2b and rule 18.2c(1) save the day, and mean that whichever boat got mark-room when Orange reached her zone continues to be entitled to mark-room.
But in practice that's still pin dancing, because if the boats are overlapped there isn't a problem,
Agree if the boats remain overlapped in inside/outside relation as they initially became overlapped..
 and if they are not overlapped there probably still isn't a problem,
I agree that in many cases once a boat breaks an overlap within the zone, she will be off and gone, but you could have, for example surfing conditions, where overlap changes are possible.
The difficulty or difference between rule 18.2b and rule 18.2a is where the overlap is broken and then boats again become overlapped, with a different boat inside::
  • under rule 18.2b, the boat previously outside, but now inside must continue to give mark-room, 
  • under rule 18.2a, the boat that now gets inside gets mark-room.
 and in any case there's always 18.2.e
Indeed there is.



Edited by Brass - 31 Jul 20 at 11:17am
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