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Tacking on a mark, room to keep clear? |
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GML
Groupie Joined: 24 Jul 11 Online Status: Offline Posts: 94 |
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Topic: Tacking on a mark, room to keep clear? Posted: 24 May 19 at 9:17am |
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18.1(a) applies at a passing mark, upwind gate or upwind finish whereas 18.1(b) may not.
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Brass
Really should get out more Joined: 24 Mar 08 Location: Australia Online Status: Offline Posts: 1146 |
Post Options Quote Reply Posted: 22 May 19 at 2:00pm | ||
Would it be worth talking/reading tactics from planet multi to get some ideas?
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Post Options Quote Reply Posted: 22 May 19 at 7:58am | ||
Thanks The slow tacks in the 800 change the boat on boat strategy quite a bit in terms of where you need to be relative to other boats to complete. It changes some of the 'set moves' from the 200 quite a bit.
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Brass
Really should get out more Joined: 24 Mar 08 Location: Australia Online Status: Offline Posts: 1146 |
Post Options Quote Reply Posted: 21 May 19 at 10:31pm | ||
Without bursting my boiler trying to think of a counter example, I'm inclined to think that you 're right and that rule 18.1b does all the work that rule 18.1a does. I think the reason for rule 18.1a is that it has always been there, it is simple and memorable. Rule 18.2b was added later to solve problems with close reaching marks. I'm not the Racing Rules Committee, I don't 'interpret' rules. I just apply them. I don't see any problem with the diagrammed scenario. @4 Y has passed head to wind, and loses her entitlement to mark-room because rule 18 ceases to apply (rule 18.1b), Y is required to keep clear of B (rule 13). B is not required to give Y room to keep clear because B acquired right of way because of Y's action in tacking (rule 15). Looks to me like Y has caused her own problem by sagging down below the layline: she would have done better to hold her lane close to the mark and wiped B off on the mark. I'm not really familiar with HP dinghys, but I think it's up to you to devise tactics that work for your boats: I don't think the rules are 'causing' the problem.
Edited by Brass - 21 May 19 at 10:39pm |
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Fatboi
Posting king Joined: 09 Aug 16 Location: Hampshire Online Status: Offline Posts: 189 |
Post Options Quote Reply Posted: 21 May 19 at 3:31pm | ||
It is all sounding very situational... Mainly depending on how close the boats are on the way in.
The tacking boat only has to get to close hauled and they are then right of way boat again. You do not have to be back to full speed or sailing, so even if doing 2kts close hauled, technically you are right of way. All you need to do is give room to keep clear - they could duck you. I guess it is all risk management. Do you need to take that risk that there will be an incident? Probably not, if so and its tight, let them round and then follow round... If you are the boat following, can you prove you had an overlap at 3, or can you prove they had not completed the tack? If not, follow round... If you hit them while they tack and your trying to avoid - they didn't give you room to keep clear. The other point is as soon as you realise you are getting into this scenario up the beat, take a high mode to ensure they need to follow your line in directly behind you. At 3 BL hail 'no room', I am sure they will back off. If not, a slow head up into the wind as you get to the mark will show their intentions. If they come inside you they have no right... Don't tack, just slowly head up... They will probably hit you and/or the mark and they are clearly in the wrong. Hopefully when you hail no room, they will back off and either follow in or bear away, so that they can get a good tack and rounding. Edited by Fatboi - 21 May 19 at 3:34pm |
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Post Options Quote Reply Posted: 21 May 19 at 2:18pm | ||
18 is is turned off as soon as you cross head to wind. So no, as soon as you cross head to wind the boat following in does not have to give you mark room.
Yes, they are on starboard. But, despite being instantly on starboard they are keep clear boat (rule 13 - While taking) until on a close hauled course. Then when they get to close hauled they acquire right of way... but are subject to rule 15 so have to still give the port boat room to keep clear.
The boats are about 5m long then crews will be 3.5 off centre. So you'd need to do about 8.5m in the time it takes them to close the gap on you.
Looking at a few tack on the entry we drop dramatically from 10 to 2 knots. So taking a high average of 6.5 knots it would take 2 second to clear the distance you need. In 2 seconds a boat doing 12 knots will do 12m... Edited by mozzy - 21 May 19 at 2:32pm |
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Post Options Quote Reply Posted: 21 May 19 at 1:45pm | ||
Thank you for the history. 18.1 turning off rule 18 for boats on opposite tacks on a beat makes complete sense. It stops port boats coming in on the layline. I know that happens at leeward marks, but there starboard boats can just bear away a little to afford room. Up wind they cannot head up without stopping and causing a pile up. However, the way it's worded seems to have some strange implications for boats reaching in to mark they shall tack around. 18.1 a) specifically makes the opposite tacks exemption for boats on a beat to windward... but then 18.1 b) seems to make opposite tacks exempt all the time. Does the diagram below change your rules interpretation? And if not, then what is the purpose of rule 18.1a)? |
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Fatboi
Posting king Joined: 09 Aug 16 Location: Hampshire Online Status: Offline Posts: 189 |
Post Options Quote Reply Posted: 21 May 19 at 1:14pm | ||
"18.2 Giving Mark-Room
(a) When boats are overlapped the outside boat shall give the
inside boat mark-room, unless rule 18.2(b) applies.
(b) 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."
Made the important part red. Does this not mean that the boat clear astern (Not overlapped at 3) shall give mark room and therefore allow the leading boat room to round? As the leading boat tacks and they are on a close hauled course, they are then on STBD, and so the following (Port) boat must still keep clear. If you are coming in on a 'fat lay' they surely would not be overlapped and would be following you in, so shouldn't really be too much of a drama. I am assuming your overstood and reaching in, so you would pass the mark while heading up to a close hauled course/tacking and for them to actually get to you, they would have to go through the mark.
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Post Options Quote Reply Posted: 21 May 19 at 1:02pm | ||
I found this in the 200 where you if you were clear ahead the boat would need to be really close behind for you not to be able to complete the tack and give them room to avoid. So you could just do a slow head up in to the tack, giving away 1/4 of a boat length to force them outside. If they're further back than that you can probably get your tack in and give them room to keep clear. But, in the 800 when you're reaching in on a fat lay at 12 knots and when you stop so much in a tack you feel quite vulnerable. Typically you'll slow to 2-3 knots and it'll take 1-2 second to go from head to wind to close hauled. A boat chasing in on the lay could be two boats lengths clear astern and still get a piece of you whilst tacking. Slowing down two boat lengths within a 3 boat length zone isn't a subtle manoeuvre and slowing down that much before a tack is a recipe for getting stuck in irons. So you effectively end up giving mark rounding position back to a boat 2 boats lengths clear astern for fear of breaking rule 13 or 15. Really, the boat clear astern should be able to pre-empt you tacking and avoid you in a similar way as they can pre-empt a gybe drop at a leeward mark and the closing speeds are even greater there. It's not like half way up the beat where they will have no idea you are about to make a significant course change and need the protection of rule 13, 15 and 16 to give them room to keep clear. Rule 18 specifically turns off those rules for roundings anyway? |
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Rupert
Really should get out more Joined: 11 Aug 04 Location: Whitefriars sc Online Status: Offline Posts: 8956 |
Post Options Quote Reply Posted: 21 May 19 at 12:45pm | ||
In general, you don't have to process it all. Much of it is logical, like in inside boat having room, but not at the very last moment, as that wouldn't give the outside boat a clear picture as the mark is approached.
And if you are just ahead of someone, they can't really avoid you if you suddenly turn 90 degrees, so you aren't allowed to do it. Hence, you turn the boat a little first to change the situation and make the tack possible. After all, we use the rules to win, but they are there to prevent crashes too, and we are all very good at finding new situations to meet other boats. |
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