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Tacking on a mark, room to keep clear?

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    Posted: 20 May 19 at 4:03pm
Blue (B) clear ahead of Yellow (Y) and slightly to leeward at 3 boats, both boat over the port layline on port. Proper course for both boats is to tack on the mark. 

18 applies before B tacks and Y is clear astern so must give B mark room. Rule 21 exonerates B whilst sailing in her mark room for Section A plus rules 15 and 16.  But, at which point is B tacking and therefore not sailing within her mark room? And at which point are they on port and starboard and so 18 no longer applies?  

Ignoring the mark the boats are going fast enough that Blue can't complete their tack and give yellow room to keep clear, so would either break 13 or 15. But as they are approaching the mark, and B was clear ahead Y should be giving blue mark room right up until position 3 (or maybe after when the tack is complete?)? 

The situation could be on a tight reach to mark your course requires you to tack around or two boat over-standing a port layline.

 




Edited by mozzy - 24 May 19 at 10:58am
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Post Options Post Options   Quote jeffers Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 19 at 4:13pm
18.2b:

If boats are overlapped when the first of them reaches the zone, the outside boat at that moment shall thereafter give the inside boat mark-room. If a boat is clear ahead when she reaches the zone, the boat clear astern at that moment shall thereafter give her mark-room.

 Mark-Room Room for a boat to leave a mark on the required side. Also, 

(a) room to sail to the mark when her proper course is to sail close to it, and 
(b) room to round the mark as necessary to sail the course. 

However, mark-room for a boat does not include room to tack unless she is overlapped inside and to windward of the boat required to give mark-room and she would be fetching the mark after her tack.

Pretty clear to me, Blue cannot tack unless she is going to be clear of Yellow at all times. Yellow is only required to give Blue Mark Room.


Edited by jeffers - 20 May 19 at 4:18pm
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 19 at 4:30pm
But... Blue can go up to head to wind without tacking. Then if the collision happens before head to wind then I guess it's yellow's foul?

So Blue should sail past the mark and wait for Yellow to tack for fear of switching off rule 18 and infringing Yellow? It seems odd that Blues mark room includes a tack when overlapped inside, but not when clear ahead. Why is that?

Could Blue slow down, force yellow outside and overlapped and then she has room to tack included in her mark room?

Or Blue slows down and yellow gets an inside overlap they are not entitled to, blue sails close to mark, but not tacking, forcing yellow to tack out? 




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Post Options Post Options   Quote jeffers Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 19 at 5:39pm
Either of the above is probably OK. The way I was told to do this was to go head to wind until the other boat has gone astern then go through to complete the tack (so like your second option but doing it at the mark). It would depend on tactical considerations for the next leg as to what the best thing to do would be. 

For example it may have been better tactically to let Yellow tack inside and you tack on top to keep a clear lane and yourself in the best tactical position to keep them behind you (depending on which way the next mark was to be rounded).

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Post Options Post Options   Quote ClubRacer Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 19 at 6:12pm
Originally posted by mozzy

  It seems odd that Blues mark room includes a tack when overlapped inside, but not when clear ahead. Why is that?


I Presume it is because if Y was so close to leeward of B that B couldn't tack without the transom stepping out and hitting Y then both boats would be locked until Y bore away to allow B to tack anyway 

Wild guess
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 19 at 7:25pm
That's what I don't really get, do you really take any more room to tack around a mark than gybe, or just head up from DDW to close hauled? I imagine the stern swinging out just as much as in any scenario. So it seems weird that the rule say you don't have room for it. 

It might make more sense if written for a boat that can't go directly to the mark within the 3 boat lengths and instead needs extra space to tack toward it. And so they can only have that space to tack toward it if overlapped inside.  

Just seems weird to not be 'allowed room to tack' when you don't actually need any over the mark room you would require if not tacking. It's not like room for a tack at an obstruction where you need to effectively turn off rule 13 and preemptively warn the other boats around. 
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 19 at 8:16pm
You can go head to wind before it counts as a tack, so unless its howling, in which case no-one should be playing 6 inch apart games anyway, a nice slow tack at the mark should see blue well clear.
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Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 19 at 10:41pm

Sorry guys, but this discussion is yet again highlighting the problems caused by using language that is not in the rules.

The rules do not use the word "tacking" or the phrase "complete a tack", nor do they say that, in any circumstances mark-room "includes a tack".
Originally posted by mozzy


Blue (B) clear ahead of Yellow (Y) and slightly to leeward at 3 boats, both boat over the port layline on port. Proper course for both boats is to tack on the mark. 
18 applies before B tacks and Y is clear astern so must give B mark room. Rule 21 exonerates B whilst sailing in her mark room for Section A plus rules 15 and 16.  But, at which point is B tacking and therefore not sailing within her mark room?

As diagrammed, B is always sailing within the mark-room to which she is entitled.

@3 + delta she will have passed head to wind and rule 18, in its entirety ceases to apply (Case 95).

@2, B is sailing in to the mark.

@3 B is sailing as necessary to round the mark.

Between @2 and @3 B is sailing within the mark-room to which she is entitled, and she can change course to round the mark as hard and as fast as she likes and will be exonerated by rule 21 if she breaks rule 16.

Between @3-delta and @3, as others have said, B can slow her turn and speed as she chooses and force Y to go around her, as long as she does not pass head to wind.



And at which point are they on port and starboard and so 18 no longer applies?

When B has passed head to wind.

Ignoring the mark the boats are going fast enough that Blue can't complete their tack and give yellow room to keep clear, so would either break 13 or 15.

or B would break rule 16 if she comes up so hard that she doesn't give Y room to keep clear.

But as they are approaching the mark, and B was clear ahead Y should be giving blue mark room right up until position 3

Yes. AND keeping clear (rules 12 then 11)

(or maybe after when the tack is complete?)?

No. Mark-room goes off when B passes head to wind


The situation could be on a tight reach to mark your course requires you to tack around or two boat over-standing a port layline.
 



This example, with B on the layline, and able to come head to wind at the mark, contrasts with Case 15, where the boat clear astern was able to pin out the boat ahead,

Case 15
Definitions, Mark-Room
Rule 12, On the Same Tack, Not Overlapped
Rule 13, While Tacking
Rule 18.1(b), Mark-Room: When Rule 18 Applies
Rule 18.2(b), Mark-Room: Giving Mark-Room
Rule 18.2(c), Mark-Room: Giving Mark-Room
In tacking to round a mark, a boat clear ahead must comply with rule 13; a boat clear astern is entitled to hold her course and thereby prevent the other from tacking


Edited by Brass - 20 May 19 at 11:00pm
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Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 19 at 11:21pm
Originally posted by ClubRacer


Originally posted by mozzy

  It seems odd that Blues mark room includes a tack when overlapped inside, but not when clear ahead. Why is that?


I Presume it is because if Y was so close to leeward of B that B couldn't tack without the transom stepping out and hitting Y then both boats would be locked until Y bore away to allow B to tack anyway 
Wild guess


Mark-room never "includes a tack". It may include "room to tack" but this only applies until the boat passes head to wind and mark-room ceases.

The arch-typical example of room to tack Elvstrom gives is, for a boat with a large overlapping Genoa, like a FD, getting room to release the genny, and have it flag out to leeward as she comes up into the tack.

I would be inclined to say that a stern-kick was just a boat sailing to, or around the mark.

Edited by Brass - 20 May 19 at 11:22pm
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 21 May 19 at 8:25am
Originally posted by Brass

Mark-room never "includes a tack". It may include "room to tack" but this only applies until the boat passes head to wind and mark-room ceases. 
Just read case 95. Seems to make zero sense. 

A boat only changes tack when they cross head to wind, up to that moment they are just heading up. Whats the point in including room to tack mark room definition when it switches of the instant it's applicable? 

Blue is free to head up to head to wind anyway, because doing so is within her mark room. Heading up to head to wind is not tacking. 

It would makes sense if the definition was giving an inside overlapped boat room to go from head to wind to close hauled without breaking rule 13, but case 95 contradicts that idea.  

I think it would be good if the rules had a definition for tack the verb. The definition of the noun defines two tacks of which you can be on one or the other, but gives no indication of  period when one might be tacking. 

Rule 13 seems to imply that 'while tacking' includes 'After a boat passes head to wind, she shall keep clear of other boats until she is on a close-hauled course.' 
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