Part 2 - WHEN BOATS MEET

(a) Rule 18 applies between boats when they are required to leave a mark on the same side and at least one of them is in the zone. However, it does not apply

• (1) between boats on opposite tacks on a beat to windward,
• (2) between boats on opposite tacks when the proper course at the mark for one but not both of them is to tack,
• (3) between a boat approaching a mark and one leaving it, or
• (4) if the mark is a continuing obstruction, in which case rule 19 applies.

(b) Rule 18 no longer applies between boats when mark-room has been given.

(a) When the first of two boats reaches the zone, (1) if the boats are overlapped, the outside boat at that moment shall give the inside boat mark-room; (2) if the boats are not overlapped, the boat that has not reached the zone at that moment shall give the other boat mark-room. When a boat is required to give mark-room by this rule, she shall continue to do so for as long as this rule applies, even if later an overlap is broken or a new overlap begins. (b) Rule 18.2(a) no longer applies if the boat entitled to mark-room passes head to wind or leaves the zone. (c) When rule 18.2(a) does not apply and the boats are overlapped, the outside boat shall give the inside boat mark-room. (d) If a boat obtained an inside overlap from clear astern or by tacking to windward of the other boat and, from the time the overlap began, the outside boat has been unable to give mark-room, rules 18.2(a) and 18.2(c) do not apply between them. (e) If there is reasonable doubt that a boat obtained or broke an overlap in time, it shall be presumed that she did not.

If a boat passes head to wind from port to starboard tack in the zone of a mark to be left to port, rule 18.2 does not apply between her and another boat on starboard tack that is fetching the mark. If the other boat has been on starboard tack since entering the zone, the boat that passed head to wind

• (a) shall not cause the other boat to sail above close-hauled to avoid contact, and
• (b) shall give mark-room if the other boat becomes overlapped inside her.

When an inside overlapped right-of-way boat must gybe at a mark to sail her proper course, until she gybes she shall sail no farther from the mark than needed to sail that course. Rule 18.4 does not apply at a gate mark.

Rule 19 applies between two boats at an obstruction except when rule 18 applies between them and (a) the obstruction is the mark, or (b) the obstruction is another boat overlapped with each of them. However, at a continuing obstruction, rule 19 always applies and rule 18 does not.

(a) A right-of-way boat may choose to pass an obstruction on her port or starboard side. If a right-of-way boat changes course when choosing on which side to pass the obstruction, she shall give the other boat room to keep clear. (b) When the boats are overlapped, the outside boat shall give the inside boat room between her and the obstruction, unless she has been unable to do so from the time the overlap began. (c) While boats are passing a continuing obstruction, if a boat that was clear astern and required to keep clear becomes overlapped between the other boat and the obstruction and, at the moment the overlap begins, there is not room for her to pass between them, (1) she is not entitled to room under rule 19.2(b), and (2) while the boats remain overlapped, she shall keep clear and rules 10 and 11 do not apply.

A boat may hail for room to tack and avoid a boat on the same tack by hailing ‘Room to tack’. However, she shall not hail unless

• (a) she is approaching an obstruction and will soon need to make a substantial course change to avoid it safely, and
• (b) she is sailing close-hauled or above. In addition, she shall not hail if the obstruction is a mark and a boat that is fetching it would be required to change course as a result of the hail.

• (a) After a boat hails, she shall give a hailed boat time to respond.
• (b) A hailed boat shall respond even if the hail breaks rule 20.1.
• (c) A hailed boat shall respond either by tacking as soon as possible, or by immediately replying ‘You tack’ and then giving the hailing boat room to tack and avoid her.
• (d) When a hailed boat responds, the hailing boat shall tack as soon as possible.
• (e) From the time a boat hails until she has tacked and avoided a hailed boat, rule 18.2 does not apply between them.

When a boat has been hailed for room to tack and she intends to respond by tacking, she may hail another boat on the same tack for room to tack and avoid her. She may hail even if her hail does not meet the conditions of rule 20.1. Rule 20.2 applies between her and a boat she hails.

• (a) When conditions are such that a hail may not be heard, the boat shall also make a signal that clearly indicates her need for room to tack or her response.
• (b) The notice of race may specify an alternative communication for a boat to indicate her need for room to tack or her response, and require boats to use it.