Last time I talked about the meaning of the term “proper course”. This month I want to talk about its use in the rules. It is not uncommon for me to hear in a description of an incident one boat claim that the other “was not sailing her proper course”. Many times when I hear this I give a slightly confused look and ask what rule requires the other boat to sail her proper course. Technically there are no rules that require a boat to sail her proper course. There are several rules that use term. Most of them provide limits, but they usually allow some other courses other than just the proper course. Often when I hear this from a boat involved in an incident, none of these rules apply. The first lesson therefore is that unless some specific rules apply (which we will discuss here), boats are not limited to sailing their proper course.
The first rule in the book that refers to proper course is rule 17.
17 ON THE SAME TACK; PROPER COURSE
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.
This rule limits some leeward boats to sailing no higher than their proper course. Please note that it does not prevent the leeward boat from sailing lower than her proper course.
(click on the diagram to see a larger cleaner version)
In the diagram the blue boat establishes an overlap to leeward from clear astern. From the time she establishes the overlap (just before position 2) to the time she is no longer overlapped (position 5) she is not allowed to sail above her proper course. We sometime say she does not have “luffing rights” though that term does not appear anywhere in the Racing Rules of Sailing. This limit only applies to boats who establish their overlap this way. Most other leeward boats do have “luffing rights”. They are allowed to sail above their proper course.
The next rule that refers to proper course is rule 18.1(b)
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,
This rule does not require anyone to sail a proper course, it just describes a situation where the mark room rule does not apply. Rule 18.1(a) and (b) together say that there is no mark-room between boats on opposite tacks at a weather mark.
The next rules that refers to “proper-course”, though indirectly are rule 18.2 and 18.3(b). Both rules establish which boats are entitled to mark-room. Rule 18.5 then exonerates boats who are entitled to mark room and break another rule while taking it. The definition of mark-room and rule 18.5 use the term proper course.
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.
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.
16 CHANGING COURSE
16.1 When a right-of-way boat changes course, she shall give the other boat room to keep clear.
This rule is the closest to telling a boat that she has to sail a proper course.
(click on the diagram to see a larger cleaner version)
In the diagram the white boat is inside overlapped as they approach the windward mark. She is entitled to mark-room which is room to sail to the mark (positions 3 to 5) and then room to sail her proper course while at the mark (position 5 to 7). At position 6 she bears off to round the mark. This is what she would do in the absence of the other boat so it is her proper course. While doing so, her stern swings out toward red and she makes contact with the red boat. She is the leeward boat, so she is right-of-way. Rule 16.1 says that when right-of-way boat alters course she shall give the other boat room to keep clear. White has broken this rule, but since she is entitled to mark-room and she is rounding the mark while sailing her proper course she is exonerated by rule 18.5. The red boat would be penalized for not giving mark room. If white was not sailing her proper course she would not be exonerated. She could not be protested for not sailing her proper course. In fact she has “luffing rights” since Red established the overlap to windward from clear astern. White could continue at position 5 and not bear off. Rule 18.5 only applies when she does sail her proper course while rounding the mark.
Next month we will continue with the other rules that refer to proper course. Those are rules 18.4 and 23.2.
© Copyright 2010 Andrew Alberti