The rules of Part 2 apply between boats that are sailing in or near the racing area and intend to race, are racing, or have been racing. However, a boat not racing shall not be penalized for breaking one of these rules, except rule 22.1. The International Regulations for Preventing Collisions at Sea or government right-of-way rules apply between a boat sailing under these rules and a vessel that is not, and they replace these rules if the sailing instructions so state.
A boat has right of way when another boat is required to keep clear of her. However, some rules in Sections B and C limit the actions of a right-of-way boat.
10 ON OPPOSITE TACKS
When boats are on opposite tacks, a port-tack boat shall keep clear of a starboard-tack boat.
11 ON THE SAME TACK, OVERLAPPED
When boats are on the same tack and overlapped, a windward boat shall keep clear of a leeward boat.
12 ON THE SAME TACK, NOT OVERLAPPED
When boats are on the same tack and not overlapped, a boat clear astern shall keep clear of a boat clear ahead.
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 shall keep clear.
14 AVOIDING CONTACT
A boat shall avoid contact with another boat if reasonably possible. However, a right-of-way boat or one entitled to room
(a) need not act to avoid contact until it is clear that the other boat is not keeping clear or giving room, and
(b) shall not be penalized under this rule unless there is contact that causes damage.
15 ACQUIRING RIGHT OF WAY
When a boat acquires right of way, she shall initially give the other boat room to keep clear, unless she acquires right of way because of the other boat's actions.
16 CHANGING COURSE
16.1 When a right-of-way boat changes course, she shall give the other boat room to keep clear.
16.2 In addition, when after the starting signal a port-tack boat is keep clear of a starboard-tack boat, the starboard-tack boat shall not change course if as a result the port-tack boat would immediately need to change course to keep clear.
17 ON THE SAME TACK; PROPER COURSE
17.1 A boat clear astern that becomes overlapped to leeward and within two of her hull lengths of a windward boat shall not sail above her proper course while the boats remain overlapped and less than that distance apart, unless as a result she falls astern of the windward boat.
17.2 Except on a beat to windward, while a boat is less than two of her hull lengths from a leeward boat or a boat clear astern steering a course to leeward of her, she shall not sail below her proper course unless she gybes.
When a Section C rule applies, the rules in Sections A and B continue to apply unless the Section C rule modifies them or states that they do not apply.
18 PASSING MARKS AND OBSTRUCTIONS
18.1 When This Rule Applies
Rule 18 applies when boats are about to pass a mark they are required to leave on the same side, or an obstruction on the same side, until they have passed it. However, it does not apply
(a) at a starting mark or its anchor line surrounded by navigable water from the time the boats are approaching them to start until they have passed them, or
(b) between boats on opposite tacks when they are on a beat to windward or when the proper course for one of them to pass the mark or obstruction is to tack.
18.2 Giving Room; Keeping Clear
(a) When boats are overlapped before one of them reaches the two-length zone, if the outside boat has right of way she shall give the inside boat room to pass the mark or obstruction, or if the inside boat has right of way the outside boat shall keep clear. If they are still overlapped when one of them reaches the two-length zone, the outside boat's obligation continues even if the overlap is broken later. This rule does not apply if the outside boat is unable to give room when the overlap begins.
(b) If a boat is clear ahead when she reaches the two-length zone, the boat then clear astern shall thereafter keep clear. Rules 10, 11 and 18.2(a) do not apply, and after the starting signal rule 16 applies only if the right-of-way boat changes course away from the mark or obstruction. If the right-of-way boat passes head to wind, rule 13 applies and this rule no longer does.
(c) If there is reasonable doubt that a boat established or broke an overlap in time, it shall be presumed that she did not.
If two boats were on opposite tacks and one of them tacked within the two-length zone to pass a mark or obstruction, rule 18.2 does not apply.
The boat that tacked
(a) shall not cause the other boat to sail above close-hauled to avoid her or prevent the other boat from passing the mark or obstruction, and
(b) shall keep clear if the other boat becomes overlapped inside her, in which case rule 15 does not apply.
When rule 18.2(a) applies and an inside overlapped right-of-way boat must gybe at the mark or obstruction to sail her proper course, she shall pass no farther from the mark or obstruction than needed to sail that course.
18.5 Passing a Continuing Obstruction
At a continuing obstruction, rule 18.2 is modified so that while boats are passing the obstruction an outside boat's obligation ends if the overlap is broken, and a boat clear astern may establish an inside overlap provided there is room at that time to pass between the other boat and the obstruction. If she does so, her obligation under rule 18.2(b) ends.
19 ROOM TO TACK AT AN OBSTRUCTION
19.1 When safety requires a close-hauled boat to make a substantial course change to avoid an obstruction and she intends to tack, but cannot tack and avoid another boat on the same tack, she shall hail for room to do so. Before tacking she shall give the hailed boat time to respond. The hailed boat shall either
(a) tack as soon as possible, in which case the hailing boat shall also tack as soon as possible, or
(b) immediately reply 'You tack', in which case the hailing boat shall immediately tack and the hailed boat shall give room, and rules 10 and 13 do not apply.
19.2 Rule 19.1 does not apply at a starting mark or its anchor line surrounded by navigable water from the time boats are approaching them to start until they have passed them or at a mark that the hailed boat can fetch. When rule 19.1 applies, rule 18 does not.
When rule 20 or 21 applies between two boats, Section A rules do not.
20 STARTING ERRORS; PENALTY TURNS; MOVING
A boat sailing towards the pre-start side of the starting line or its extensions to comply with rule 29.1 or rule 30.1 shall keep clear of a boat not doing so until she is completely on the pre-start side. A boat making penalty turns shall keep clear of one that is not. A boat moving astern by backing a sail shall keep clear of one that is not.
21 CAPSIZED, ANCHORED OR AGROUND; RESCUING
If possible, a boat shall avoid a boat that is capsized or has not regained control after capsizing, is anchored or aground, or is trying to help a person or vessel in danger. A boat is capsized when her masthead is in the water.
22 INTERFERING WITH ANOTHER BOAT
22.1 If reasonably possible, a boat not racing shall not interfere with a boat that is racing.
22.2 A boat shall not deliberately interfere with a boat making penalty
turns to delay her.