260924 KYC RS21 Thursday Race

Creation: 260925 0609 Last Modified: 260925 0609

Crew

Position	Person
Helm	Sue Fraser
Main	Steve Ellwood
Middle	Anik Karimjee
Bow	Howard Whittaker

Course

SO2 - very short

Weather

6-10 knots from the NE Seemed to be a move to the left, making the port tack the long tack Pressure and puffs on the club side, left.

Race Result

3rd. The two Queen’s races crews beat us.

Race Review

Our race came down to a tactical error at the first windward mark, S. Blue has badly overstood and were coming into the mark reaching with great speed. Nonetheless they were going to get to the weather mark almost as we did.

Lynn took a video of the rounding. This video is below.

Using Anthropic’s Claude Opus 5.5 this video has been converted into a bird’s eye view of events.

Note - something I didn’t have right. The ‘circle’ is defined by the length of the FIRST boat entering the circle, not the longest involved in the event.

RRS Text “The area around a mark within a distance of three hull lengths of the boat nearer to it. A boat is in the zone when any part of her hull is in the zone.”

Opus Response

No. The zone isn’t set by the boat that enters it first. It’s set by the boat nearer the mark, and it is measured separately for each pair of boats.

What the rule says. Your vault copy of the 2025–2028 rules defines the zone as:

“The area around a mark within a distance of three hull lengths of the boat nearer to it. A boat is in the zone when any part of her hull is in the zone.”

What that means in practice

1. It is worked out for each pair of boats. Rule 18 applies between two boats at a time, so for any pair, the zone is three lengths of whichever of the two is nearer the mark.
2. It can change size. If the other boat becomes the nearer one, the zone switches to her length. With two boats of the same length, like two RS21s, it doesn’t change.
3. “In the zone” means any part of the hull, not the centre or the bow.
4. The confusion probably comes from rule 18.2(a), where timing does matter. The mark-room obligation is fixed at the moment “the first of two boats reaches the zone.” That boat is only the trigger. The size of the zone at that moment is still set by the nearer boat’s length. Usually the first boat to reach the zone is also the nearer one, so the two ideas get mixed up.
5. Sailing instructions can’t change it for fleet racing. Rule 86.1(b) bars the notice of race and sailing instructions from changing the Definitions or Part 2. Only certain appendices change the distance: for example, Appendix C (match racing) uses two hull lengths, and another appendix uses four.

Applied to this rounding

Pair	Nearer boat	Zone
Pink and Blue (or any two RS21s)	Either one	3 × 21 ft = 63 ft
RS21 and J80	RS21	63 ft
RS21 and J80	J80	3 × 26.3 ft = 79 ft
RS21 and Abbott 33	RS21	63 ft
RS21 and Abbott 33	Abbott	3 × 33 ft = 99 ft

In the diagram, Pink was nearer the mark than the Abbott when she tacked at about 22 s, so the 63 ft zone was the right one for that tack. When the Abbott later became the nearer boat, the zone between her and Pink grew to 99 ft. By then Pink had already tacked, so it doesn’t change anything in the analysis.

The diagram draws only the 63 ft circle. That’s correct for the Pink–Blue incident but not for pairs where the J80 or the Abbott is nearer. If you’d like, I can add faint 79 ft and 99 ft circles that appear only when one of the bigger boats is the nearer one in a pair.

SJE -> I believe the circle does not change size as a boat passes another boat within the circle - this idea might be incorrect.

Bird’s-Eye Diagram and Rules Analysis (v12)

Animated diagram: a 71-second recording of the diagram, running in time with Lynn’s video.

Opus Response — v12

What the diagram shows

• Blue’s approach: she comes in well above the port layline and fast, overhauling Pink to windward.
• Blue enters the circle first, at 8.05 s.
• Pink enters at 8.55 s, overlapped with Blue. Blue is about 30 ft to windward and 12 ft ahead of her, on the mark side.
• The sequence:
  • At 14 s Pink bears away toward the Abbott’s stern.
  • Blue crosses in front of the mark at 17 s.
  • At 21 s Pink changes her mind and tacks, which forces Blue to tack at 22.2 s.
  • At 23.3 s Pink’s port side hits Blue’s starboard side, about 7.5 ft apart centre to centre.
• Rounding order: J80, Abbott (with Blue overlapped inside), Blue, Pink, then Orange at 35 s.
• Penalty: Pink starts penalty turns at 55 s, turning left. The video ends before the first turn is complete.
• Limits: positions are illustrative, not measured. With Blue higher and nearer the mark, the J80 crossing at 13 s is only approximate: Blue passes just ahead of the J80 as it bears away, rather than cleanly across its bow.

What this means for Pink

1. The mark-room obligation is on Pink. Blue reached the zone first, overlapped inside. Under rule 18.2(a)(1), Pink, as the outside boat, “shall give the inside boat mark-room” and must keep doing so while the rule applies. Pink’s own tack doesn’t end that obligation. It ends only when Blue, the boat entitled to it, passes head to wind or leaves the zone (18.2(b)). In the diagram that is 23.0 s, after Pink has already forced her to tack.

2. The rules Pink broke:

• Rule 13 (the main one). After passing head to wind, Pink had to keep clear of Blue, who was still on port and had right of way. Blue had to tack to avoid her, and a boat that makes the right-of-way boat take avoiding action is not keeping clear.
• Rule 18.2(a), probably. Luffing and tacking into the inside boat beside the mark, instead of giving her room to sail to it and round it.
• Rule 16.1, possibly. It applies to her luff before head to wind, when she was still the right-of-way boat but was changing course.

3. Blue is protected in every direction:

• She is exonerated for anything Pink’s breach compelled her to do (43.1(a)).
• While she was within the mark-room she was entitled to, she is also exonerated for breaking a Section A rule, rule 15 or rule 16 (43.1(b)). That removes any argument that she wasn’t keeping clear as the windward boat.
• She is exonerated for the contact itself under rule 14 if there was no damage (43.1(c)).

4. Pink has no route to exoneration. She wasn’t entitled to mark-room, and nothing Blue did compelled her. (An earlier draft suggested Blue “tacked for the Abbott”. That came from misreading who changed their mind. It was Pink, so that defence never applied.)

5. What would have cleared Pink: only a correct Two-Turns Penalty (44.1, 44.2), meaning two turns in the same direction, each with a tack and a gybe, taken promptly once well clear. Or retiring, if there was serious damage. Turns to the left and then the right are not a valid penalty. If Blue protested, the committee had to find that Pink broke rule 13 and then disqualify her (60.5(c)).

Caveat: Blue’s overlap when she reached the zone depends on Steve’s recollection. If it were disputed, rule 18.2(e) would presume Blue did not get the overlap in time, so Pink’s crew would argue about that point. The rule 13 breach doesn’t depend on the overlap at all.

Comments

Comments from the web site, captured two weeks after the event.

SF — 260925 0919

From the video it looks like the Abbot was outside the zone when pink and blue entered.