In last months article we started to talk about tacking too close. The examples last month were nowhere near the weather mark. This month we will talk about one boat tacking at the weather mark. The first thing to understand is that rule 13 still applies, so if the boat on starboard has to alter course before the tacking boat completes her tack, then the tacking boat has broken the rule.
There more restrictions on the tacking boat when the tack happens near the weather mark. Those restrictions are found in rule 18.3
13 WHILE TACKING
After a boat passes head to wind, she shall keep clear of other boats until she is on a close-hauled course. During that time rules 10, 11 and 12 do not apply. If two boats are subject to this rule at the same time, the one on the other’s port side or the one astern shall keep clear.
18.3 Tacking When Approaching a Mark
If two boats were approaching a mark on opposite tacks and one of them changes tack, and as a result is subject to rule 13 in the zone when the other is fetching the mark, rule 18.2 does not thereafter apply. The boat that changed tack
(a) shall not cause the other boat to sail above close-hauled to avoid her or prevent the other boat from passing the mark on the required side, and
(b) shall give mark-room if the other boat becomes overlapped inside her.
(click on the diagram to see a larger cleaner version)
In the diagram, the red boat is set to cross in front of the yellow and green boats. She tries to tack in between the two. At position 4 she has completed her tack and neither boat has had to alter course to avoid her so she has complied with rule 13. Since red has changed tacks and has been subject to rule 13 within the zone, rule 18.3 applies. Yellow ends up establishing an overlap inside red so even though yellow was neither clear ahead of nor overlapped inside red when she got to the zone, she is entitled to mark-room from red. Red has to give her room to sail to the mark and to sail her proper course at the mark. Yellow was right on the lay line but has to pinch up to get around the mark. As long as she can do it without passing head to wind she is “fetching” the mark. Red has to give her room including room to pinch up. In the diagram red does this so she does not break a rule relative to yellow.
Green is a little above the lay line. When red completes her tack she is directly in front of green, but green is sailing faster. Green alters course to sail above red. If there was no mark involved there would be no rule broken here, but green ends up sailing above a close hauled course to avoid hitting red. Red therefore breaks rule 18.3 (a).
(click on the diagram to see a larger cleaner version)
In the second diagram the blue boat had overstood the mark. She has to alter course after the red boat tacks but this time her alteration of course is up to close-hauled but not above it. Red has technically not broken a rule. I will however say that red is taking a risk. It is hard to prove that blue was not above close-hauled. Her jib will probably luff since it was trimmed for a slightly lower course. Tacking at the mark is always a risky choice.
© Copyright 2010 Andrew Alberti