Sunday, 22 March 2009

Zoning Laws

Yesterday, at the Heiner Team Racing Winter series final, I had a conversation with the other umpires about ‘the zone’, specifically when boats of different length are rounding the same mark.

Lots of events locally are multiclass events were this can happen. Now, this is not something new, it happened just as frequently under the 2005-2008 RSS. But because the sharp ‘border’ at which rule 18 switches on and because the zone has become bigger, it might be more of an issue.

This is the situation and questions we asked ourselves:

Yellow is a 8 meter Regenboog and Blue is an Optimist, sailing toward a leeward rounding mark to be left at port. The Optimist is closest to the mark when she reaches the zone of the Regenboog. By the time the Optimist has almost reached her zone, the Regenboog as overtaken her and enters that zone first.

If any, which boat has mark-room and from where? Which rules apply? Which zone applies and why? Has any boat broken a rule? Anyway, you get the drift, a purely hypothetical case.

We did come up with an answer, but I’m not going to tell you. Please consider this in your own time and leave a comment. After a couple of days I’ll do the same or post our answer in a blogpost.


  1. The definition of zone reads 'three lengths of the boat nearest to it"
    Until position 3, or slightly before the Opi is 'nearest' but as she is not within three lengths 18 does not apply.
    18.2(b) does not apply because when the bigger boat entered 'her' zone she was not the first boat.
    I would apply 18.2(a) and the big boat gets room!

  2. @1 Opti is nearer to the mark and zone is defined by Opti. Opti is certainly CAHD, but rule 18 does not apply.

    @2 Opti is nearer to the mark and zone is defined by Opti. Boats are certainly overlapped. Opti is nowhere near the zone: rule 18 does not apply.

    @2.5 8m is nearer to the mark and zone is defined by 8m. The 8m has 'reached' the zone. Boats are certainly overlapped. Rule 18.2(b) applies and the Opti must give the 8m mark-room, and continue to do so.

    @3 and @4 the Opti must continue to give the 8m mark-room.

    Just before and after @2.5 is where potential for confusion arises. Up to the instant that the 8m's bow draws ahead of the Opti's bow, the Opti is ROW boat with no obligation to give mark-room, so the ant can attack the elephant. The Opti can luff on port towards the 8m and the 8m must respond, except that, as the much slower Opti luffs towards the 8m, the 8m's bow will, inevitably come ahead of the Opti's bow and the 8m will become entitled to mark-room, and will need to bear away pronto. This is reminiscent of Bryan Willis' contention that an outside boat not quite at the zone, must pre-emptively steer sufficiently outside the direct course to the mark so that the inside boat will, at the instant the first of them reaches the zone, have her mark-room.

    Supposing I am wrong and that the 8m's zone is not correctly 'switched on' by her bow drawing ahead of the Opti's bow @2.5. In this case

    @3, the 8m reaches the zone defined by the Opti's length, and not later than then, the 8m becomes entitled to mark-room. So there is, at worst about half a boat length (of the 8m) of time and space during which there is any legitimate uncertainty.

  3. I tend towards Brass' idea that the Regenboog switches her [larger] zone on between 2 and 3.

    But then 18.2b says 'if boats are overlapped when the first reaches the zone'. Looking back at the larger zone, this wasn't the case here so the Regenboog should be giving the Optimist mark room.

    Having said that, a wise Optimist sailor would let the Regnboog get round the mark first and not have her coming through to windward at the beginning of the beat.

  4. Andrew

    I can understand the logic but it will become very difficult if we say the zone changes from the small to larger zone between positions 2 and 3 (when regenboog becomes nearest)and sailors then have to think back to what the relationship was at position 1.
    Hours of fun for the Protest committee.

  5. Interesting problem. Kinda feel for the kid in the Opti. 18.2(a) takes over giving the inside overlapped boat the right to mark room if 18.2(b) doesn't apply.

  6. Looks like the first boat to enter the zone is the 8 meter and as inside boat is entitled to mark room. 18.2.b. no zone can apply until a boat gets there and the zone is controlled by the closer boat. This is initially the optimist but later becomes the 8 meter. If the optimist could not give room then 18.2.e could apply. No rules appeared to be broken.

  7. This sounds like fun so I will give this one a try.

    At pos 1.The Zone is defined by the Opti (she is nearer to the mark) but neither boat has entered the Opti’s Zone and 18 is not turned on.

    At pos 2. The Zone is still defined by the Opti (she is still nearer to the mark) but still, neither boat has entered the Opti’s Zone and 18 is not turned on.

    At pos 3 the Opti has not reached the Zone (her Zone), but now, the 8 meter is nearer the mark so the Zone is now redefined by the 8 meter. And since the 8 meter is in the Zone (his Zone) 18 is on, per 18.1. And as Brian says, 18.2(a) applies and the Opti must give the 8 meter Mark Room. Move over kid.

    So does the definition of Zone say?

    “If you enter your Zone before the other boat mentioned in the rule enters your Zone, when the other boat is a greater OAL than you, you are the Zone definer (herein after called the “Zoner”). But if the other boat mentioned in the rule is a lessor OAL than you, and he enters your zone before you enter your Zone you are not the “Zoner” any more, he is, or might be, if no other boat of greater or lessor OAL passes him bow to bow. And, if another boat, of greater OAL than you, enters your Zone before you do then that boat is the “Zoner” retroactive to when he entered his Zone after you.

    I have to give credit to the rules writers for saying in only 18 words what I have taken 118 words to say.

  8. Brain has, in his first comment, the right solution. Rule 18.2(b) is never switched on, so only 18.2(a) is to be applied. And 18.2(e); if the optimist is unable, then she doesn't have to give mark room.

  9. In this case, when does the 8m become entitled to mark-room?

    Surely not @1.5, when the 8m is 3x8m lengths from the mark? We know that is not the 'zone' because the zone is defined by the length of the boat nearest the mark.

    Is it when the bow of the 8m first becomes nearer to the mark than the bow of the Opti?

  10. I believe it is either when the opi enters her zone (as the boats would be overlapped at this time) or when the 8m becomes closest to the mark (this is when her zone turns on and the boats are overlapped and in the zone)
    ie whenever one of the zones becomes effective.
    Whichever is the first (in this case when the 8m becomes closest.


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