Rules Answer for Tillerman

Tillerman asked a Rules Question on his blogpost today:

Here's a question for all you Racing Rules of Sailing experts out there…
When do you have to sail your proper course?


There are five rules where proper course is mentioned.
Most sailors will know the first one:

Rule 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.

The rule does not restrict your course in sailing lower then your proper course….. therefore in answer to the question: You don't have to sail your proper course.

Rule 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
(b) between boats on opposite tacks when the proper course at the mark for one but not both of them is to tack,

Again, it does not say you have to sail your proper course….

Rule 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.

This rule restricts you distance to the mark…
You have to gybe if you are inside overlapped right-of-way boat. You can sail higher or even to the wrong side if you want… So agian, in answer to the question, you don't have to sail your proper course….

Rule 18.5 Exoneration
When a boat is taking mark-room to which she is entitled, she shall be exonerated
(b) if, by rounding the mark on her proper course, she breaks a rule of Section A or rule 15 or 16.

Again, no restrictions, but if you break one of the rules mentioned, you better be on a proper course. But if you don't break any of the rules, you can sail wherever you want…

Rule 23.2 Except when sailing her proper course, a boat shall not interfere with a boat taking a penalty or sailing on another leg.

Interfering with a boat on another leg or taking a penalty may only happen if you sail on your proper course. But nothing in this fifth rule, restricts you from sailing another course…. as long as you don't interfere with another boat.

In answer to the question I would have to say: According to the RRS, you don't have to sail your proper course…. there's always another (worse) course if you want it.