Saturday, March25, 2017

When Boats Meet

Below is the section of 2009-2012 rules dealing with when boats meet. I start with the definitions, which are at the end of the rule book for some strange reason. It is a lot easier to understand the rules if you know what the words mean first.


A term used as stated below is shown in italic type or, in preambles, in bold

italic type.

Abandon A race that a race committee or protest committee abandons is

void but may be resailed.

Clear Astern and Clear Ahead; Overlap One boat is clear astern of another

when her hull and equipment in normal position are behind a line abeam

from the aftermost point of the other boat's hull and equipment in normal

position. The other boat is clear ahead. They overlap when neither is clear

astern. However, they also overlap when a boat between them overlaps both.
These terms always apply to boats on the same
tack. They do not apply to

boats on opposite tacks unless rule 18 applies or both boats are sailing more

than ninety degrees from the true wind.

Fetching A boat is fetching a mark when she is in a position to pass to

windward of it and leave it on the required side without changing tack.

Finish A boat finishes when any part of her hull, or crew or equipment in

normal position, crosses the finishing line in the direction of the course from the
mark, either for the first time or after taking a penalty under rule 44.2 or,
after correcting an error made at the finishing line, under rule 28.1.

Interested Party A person who may gain or lose as a result of a protest

committee's decision, or who has a close personal interest in the decision.

Keep Clear One boat keeps clear of another if the other can sail her course

with no need to take avoiding action and, when the boats are overlapped on

the same tack, if the leeward boat can change course in both directions

without immediately making contact with the windward boat.

Leeward and Windward A boat's leeward side is the side that is or, when

she is head to wind, was away from the wind. However, when sailing by the

lee or directly downwind, her leeward side is the side on which her mainsail

lies. The other side is her windward side. When two boats on the same tack

overlap, the one on the leeward side of the other is the leeward boat. The

other is the windward boat.

Mark An object the sailing instructions require a boat to leave on a specified

side, and a race committee boat surrounded by navigable water from

which the starting or finishing line extends. An anchor line or an object

attached temporarily or accidentally to a mark is not part of it.

Mark-Room Room for a boat to sail to the mark, and then room to sail her

proper course while at the mark. However, mark-room does not include

room to tack unless the boat is overlapped to windward and on the inside of

the boat required to give mark-room.

Obstruction An object that a boat could not pass without changing course

substantially, if she were sailing directly towards it and one of her hull

lengths from it. An object that can be safely passed on only one side and an

area so designated by the sailing instructions are also obstructions. However,

a boat racing is not an obstruction to other boats unless they are required to
keep clear
of her, give her room or mark-room or, if rule 22 applies, avoid

her. A vessel under way, including a boat racing, is never a continuing


Overlap See Clear Astern and Clear Ahead; Overlap.

Party A party to a hearing: a protestor; a protestee; a boat requesting

redress; a boat or a competitor that may be penalized under rule 69.1; a race

committee or an organizing authority in a hearing under rule 62.1(a).

Postpone A postponed race is delayed before its scheduled start but may be

started or abandoned later.

Proper Course A course a boat would sail to finish as soon as possible in

the absence of the other boats referred to in the rule using the term. A boat

has no proper course before her starting signal.

Protest An allegation made under rule 61.2 by a boat, a race committee or a

protest committee that a boat has broken a rule.

Racing A boat is racing from her preparatory signal until she finishes and

clears the finishing line and marks or retires, or until the race committee

signals a general recall, postponement or abandonment.

Room The space a boat needs in the existing conditions while manoeuvring

promptly in a seamanlike way.

Rule (a) The rules in this book, including the Definitions, Race Signals,

Introduction, preambles and the rules of relevant appendices,

but not titles;

(b) ISAF Regulation 19, Eligibility Code; Regulation 20, Advertising
Code; Regulation 21, Anti-Doping Code; and Regulation

22, Sailor Classification Code;

(c) the prescriptions of the national authority, unless they are

changed by the sailing instructions in compliance with the

national authority's prescription, if any, to rule 88;

(d) the class rules (for a boat racing under a handicap or rating

system, the rules of that system are 'class rules');

(e) the notice of race;

(f) the sailing instructions; and

(g) any other documents that govern the event.

Start A boat starts when, having been entirely on the pre-start side of the

starting line at or after her starting signal, and having complied with rule 30.1

if it applies, any part of her hull, crew or equipment crosses the starting line

in the direction of the first mark.

Tack, Starboard or Port A boat is on the tack, starboard or port, corresponding

to her windward side.

Zone 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.

Windward See Leeward and Windward.




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 23.1.

When a boat sailing under these rules meets a vessel that is not, she

shall comply with the International Regulations for Preventing Collisions

at Sea (IRPCAS) or government right-of-way rules. If the sailing

instructions so state, the rules of Part 2 are replaced by the rightof-

way rules of the IRPCAS or by government right-of-way rules.



A boat has right of way when another boat is required to keep clear

of her. However, some rules in Sections B, C and D limit the actions

of a right-of-way boat.


When boats are on opposite tacks, a port-tack boat shall keep clear of

a starboard-tack boat.


When boats are on the same tack and overlapped, a windward boat

shall keep clear of a leeward boat.


When boats are on the same tack and not overlapped, a boat clear

astern shall keep clear of a boat clear ahead.


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





A boat shall avoid contact with another boat if reasonably possible.

However, a right-of-way boat or one entitled to room or mark-room

(a) need not act to avoid contact until it is clear that the other boat

is not keeping clear or giving room or mark-room, and

(b) shall not be penalized under this rule unless there is contact

that causes damage or injury.


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.


16.1 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 keeping

clear by sailing to pass astern 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 continue keeping



If a boat clear astern becomes overlapped within two of her hull

lengths to leeward of a boat on the same tack, she shall not sail above

her proper course while they remain on the same tack and overlapped

within that distance, unless in doing so she promptly sails

astern of the other boat. This rule does not apply if the overlap

begins while the windward boat is required by rule 13 to keep clear.



Section C rules do not apply at a starting mark surrounded by navigable

water or at its anchor line from the time boats are approaching

them to start until they have passed them. When rule 20 applies,

rules 18 and 19 do not.


18.1 When Rule 18 Applies

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

(a) between boats on opposite tacks on a beat to windward,

(b) between boats on opposite tacks when the proper course at the

mark for one but not both of them is to tack,

(c) between a boat approaching a mark and one leaving it, or

(d) if the mark is a continuing obstruction, in which case rule 19


18.2 Giving Mark-Room

(a) When boats are overlapped the outside boat shall give the

inside boat mark-room, unless rule 18.2(b) applies.

(b) If boats are overlapped when the first of them reaches the zone,

the outside boat at that moment shall thereafter give the inside

boat mark-room. If a boat is clear ahead when she reaches the

zone, the boat clear astern at that moment shall thereafter give

her mark-room.

(c) When a boat is required to give mark-room by rule 18.2(b), she

shall continue to do so even if later an overlap is broken or a

new overlap begins. However, if either boat passes head to

wind or if the boat entitled to mark-room leaves the zone, rule

18.2(b) ceases to apply.

(d) If there is reasonable doubt that a boat obtained or broke an

overlap in time, it shall be presumed that she did not.

(e) If a boat obtained an inside overlap from clear astern and,

from the time the overlap began, the outside boat has been

unable to give mark-room, she is not required to give it.

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.

18.4 Gybing

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.

18.5 Exoneration

When a boat is taking mark-room to which she is entitled, she shall

be exonerated

(a) if, as a result of the other boat failing to give her mark-room,

she breaks a rule of Section A, or

(b) if, by rounding the mark on her proper course, she breaks a

rule of Section A or rule 15 or 16.


19.1 When Rule 19 Applies

Rule 19 applies between boats at an obstruction except when it is

also a mark the boats are required to leave on the same side. However,

at a continuing obstruction, rule 19 always applies and rule 18

does not.

19.2 Giving Room at an Obstruction

(a) A right-of-way boat may choose to pass an obstruction on

either side.

(b) When 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, she is not entitled to room under rule 19.2(b). While the boats remain overlapped, she shall keep clear and rules 10 and 11 do not apply.
20.1 Hailing and Responding When approaching an obstruction, a boat sailing close-hauled or above may hail for room to tack and avoid another boat on the same tack. After a boat hails, (a) she shall give the hailed boat time to respond; (b) the 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; and (c) when the hailed boat responds, the hailing boat shall tack as soon as pos
20.2 Exoneration When a boat is taking room to which she is entitled under rule 20.1(b), she shall be exonerated if she breaks a rule of Section A or rule 15 or 16.
20.3 When Not to Hail
A boat shall not hail unless safety requires her to make a substantial course change to avoid the obstruction. Also, she shall not hail if the obstruction is a mark that the hailed boat is fetching.

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