A word in italics (or bold italics) in the Racing Rules of Sailing for 1997-2000 (the RRS) has a special meaning that is given in the Definitions section of the RRS. To properly understand a rule that uses a defined word you must separately consider and understand the special meaning of the defined word. Only those defined words used in the r-o-w rules, Part 2 (When Boats Meet), are discussed here or in Selected Definitions - Part 2. Abbreviations, such as r-o-w, are explained in the Introduction.

Clear Astern,
Clear Ahead,
Overlap
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's hull and equipment in normal position. The other boat is clear ahead. They overlap when neither is clear astern or when a boat between them overlaps both. These terms do not apply to boats on opposite tacks unless rule 18 applies.


Overview Clear ahead, clear astern and overlap all relate to whether or not two boats are overlapped (and many of the rules vary depending on whether an overlap exists). Used in: Rules 11, 12, 17.1, 17.2, 18.1, 18.2, 18.3, 18.4, 18.5 and Keep Clear.
Basic In determining whether two specific boats are "overlapped" under the definition you must first consider whether the terms of the definition can even apply to them. Clear ahead, clear astern and overlap do not apply to boats on opposite tacks unless Rule18 (Passing Marks and Obstructions) applies because the boats are "about to pass" or are passing a mark or obstruction. Thus, even though two boats may be physically overlapped, unless Rule 18 applies both boats must be on the same tack to be "overlapped" under the definition.
Next, if two boats are either on the same tack or "about to pass" (or passing) a mark or obstruction (so Rule 18 applies) then to determine whether they are "overlapped" you must decide whether they satisfy the "physical test" of overlap. First, one boat is clear astern of another if she (meaning her hull and equipment in normal position) is totally behind a line drawn perpendicular to the other's aftermost point (including hull and equipment in normal position). In Diagram 1, if no part of B is ahead of the dotted line (which is perpendicular to the centerline of A and through her aftermost point) then B is clear astern of A. If one boat is clear astern then the other is clear ahead, so A is clear ahead of B. Second, two boats overlap if neither is clear astern of the other (or if each overlaps a boat that is in between them). In Diagram 1, A and C overlap since C is not clear astern of A (some part of C's hull and equipment in normal position is ahead of the dotted line through A's aftermost point).
In deciding whether an overlap exists, it is important to look from the viewpoint of the stern of the boat ahead and not the bow of the boat behind. See Example 2 below.
Advanced If boats are on opposite tacks then "overlap" (and "clear astern" and "clear ahead") do not apply unless Rule 18 applies. Since Rule 18 does not apply to boats on opposite tacks at a windward mark (see Rule 18.1), this means that boats on opposite tacks at a windward mark cannot be "overlapped."
An overlap is created in one of three ways, (a) from clear ahead or clear astern, (b) when a boat changes tacks so that both boats become on the same tack or (c) when boats are on opposite tacks and Rule 18 (Passing Marks and Obstructions) begins to apply.
The idea in the IYRR definition that an overlap automatically terminates or commences when a boat changes tacks, crosses the starting line or comes within a certain distance of another boat is eliminated (though certain rules do not apply to overlapped boats when they are more than two hull lengths apart). Thus, if two boats on the same tack are subject to Rule 18 and one of them gybes then the same overlap will continue to exist. Note that how an overlap was created is only really important with respect to determining whether Rule 17.1 (On the Same Tack; Proper Course) applies.
Examples In Example 1, B is overlapped with A because they are both on port tack and part of B's hull and equipment in normal position is ahead of a line drawn through the aftermost point of A's hull and equipment in normal position. C is not overlapped with either A or B because neither of them is on the same tack as C.
In Example 2, D and E are on the same tack. However, E is clear astern of D, and thus not overlapped with D, because she is completely behind a line drawn at right angles to D's centerline through the aftermost point of D's hull and equipment in normal position. This true even though sighting at right angles from E's bow (solid red line) the two boats might appear to be overlapped. It is the line drawn through D's stern (not E's bow) that is relevant.
In Example 3, P and S are about to pass on the same side of an anchored boat. P and S are overlapped because although they are on opposite tacks Rule 18 applies to them. Rule 18 applies because both boats are about to pass a mark or obstruction on the same side. See Rule 18.1.

In Example 4, P and S are approaching a windward mark to be left to port. P and S are not overlapped because they are on opposite tacks and Rule 18 does not apply. Even though P and S are about to pass a mark or obstruction on the same side, Rule 18 does not apply because one of them will have to tack to pass the mark (Rule 18 does not apply at a windward mark). See Rule 18.1.
Finish Finish
A boat finishes when any part of her hull, or crew or equipment in normal position, crosses the finishing line in the direction from the last mark either for the first time or, if she takes a penalty, after complying with rule 31.2 or rule 44.2.


Overview Finish determines when a boat finishes the race for timing purposes but not whether she is done racing. Used in: Proper Course and Racing.
Basic Under this definition you "finish" when you cross the finish line from the direction of the last mark after taking any penalty turns that you may wish to take under either Rule 31.2 (Touching a Mark) or Rule 44.2 (720 Turns Penalty) as a result of breaking a rule.
Advanced Whether you receive a sound signal from the RC is not relevant as to whether you have properly finished. And, under Rule 86.1 (Rule Changes) the definition of "finish" may not be changed by the sailing instructions or otherwise. This means that if the sailing instructions say to "finish" in a manner different from the definition you are supposed to ignore the sailing instructions and finish in accordance with the definition. See the Example below.
Example In Example 5, the RC has set up a finish line between X and the RC boat. The sailing instructions say that boats must leave all marks to port, specifically including X. To finish in accordance with the sailing instructions, A would need to "round" X and cross the finish line heading back toward the last mark (performing a "buttonhook" turn to cross the finish line). To "finish" properly, A must ignore the sailing instructions and cross the finish line from the direction of the last mark (leaving X to starboard).
Related What if you hit a finish mark after you have crossed the finish line but before you have cleared the finish line and marks? Under the definition of "racing", you are still "racing" until you have "clear[ed] the finishing line and marks." And, while you are still "racing," Rule 31.1 (Touching a Mark) continues to apply. So although under the definition of "finish" you have officially finished the race, you are still subject to protest and DSQ under Rule 31.1 for touching a mark while "racing." You may, however, exonerate yourself by taking the penalty provided in Rule 31.2 by doing a 360 turn, returning completely to the course side of the finish line and "finishing" again.
Keep Clear Keep Clear
One boat keeps clear of another if the other boat 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 could change course without immediately making contact with the windward boat.


Overview Keep clear determines whether a giveway boat has met her obligation to keep clear of the r-o-w boat. Used in: Preamble to Sec. A, Rules 10, 11, 12, 13, 14, 15, 16, 18.2, 18.3 and 20.
Basic If a r-o-w boat can sail her course without taking any "avoiding action" then the giveway boat has kept clear. "Avoiding action" certainly includes any course change by the r-o-w boat that is necessary to avoid the giveway boat (e.g., where P fails to act to avoid a converging S and S is thus required to change course to avoid hitting P). In addition, it includes any continuation of course by a r-o-w boat when she wants to change course but cannot because the giveway boat refuses to "promptly" act to keep clear (e.g., S and P sailing side by side downwind with S on the left-hand side of P; S hails P that she wants to luff but P refuses to respond "promptly in a seamanlike way" to give S room to do so).
Advanced If a r-o-w boat takes avoiding action that a PC later determines was reasonable in the circumstances then I believe the PC should find that the giveway boat did not "keep clear," even if in hindsight it appears that the avoiding action was not strictly necessary in that situation. In other words, the giveway boat must do more than avoid hitting the r-o-w boat, she must stay far enough from the r-o-w boat so that the r-o-w boat has no reasonable apprehension of collision with the giveway boat.
Where a r-o-w boat (L) and a giveway boat (W) are on the same tack and overlapped then W keeps clear of L only if she is far enough from L so that L can change course without immediately making contact with W. This does not mean that L is entitled to enough room to do a "sharp luff" but W should allow L enough room to make a course change in either direction that is more than minor.
Example In Example 6, W and L are on the same tack and overalpped and sailing on courses that are slowly converging. Eventually, W is sailing so close to L that if L were to make more than a minor course change she would immediately make contact with W. W has not "kept clear" of L within the meaning of the definition of "keep clear" and has therefore broken Rule 11. See Rule 11.
Related Under the preamble to Section A, when one boat is required to "keep clear" of another, the other boat is said to have "right of way."
Leeward,
Windward
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.


Overview Leeward and windward determine which will be the windward and leeward sides of a boat, or which will be the windward and leeward boats when two boats are on the same tack and overlapped. Used in Rules 11, 17.1, 17.2, Keep Clear and Tack, Starboard or Port.
Basic The leeward side is the side away from the direction of the wind and the other is the windward side except in two special circumstances: (1) when a boat is head to wind (in which case the former leeward and windward sides remain so) and (2) when a boat is sailing directly downwind or by the lee (in which case the position of the mainsail, not the direction of the wind, determines windward and leeward; the side of the boat that the mainsail is on is leeward).
Mark Mark
An object the sailing instructions require a boat to pass on a specified side, excluding its anchor line and objects attached temporarily or accidentally.


Overview Mark determines which objects will be "marks" under the rules for purposes of Rules 18 (Passing Marks and Obstructions), 28 (Sailing the Course) and 31 (Touching a Mark). Used in: 18.1, 18.2, 18.3, 18.4, 19.2, Finish, Racing and Two-Length Zone.
Basic A mark is any object that according to the sailing instructions must be passed on a particular side, including the marks which indicate the ends of the starting and finishing lines. The anchor line of a buoy that is a mark (similarly, the underwater area around an island that is a mark) is not considered part of the mark.
Advanced An object temporarily attached to a mark (such as a dinghy tied to the stern of a vessel serving as a mark) is not part of the mark so touching such an object would not break Rule 31.1 (Touching a Mark). Moreover, Rules 18 (Passing Marks and Obstructions) and 19 (Room to Tack at an Obstruction) would apply with respect to such an object (although they may not with respect to the mark itself).

Additional defined terms are discussed in Selected Definitions - Part 2.

First Edition, March 1997
Copyright © 1997 Arthur Engel, All Rights Reserved