This engages rules 11, 12, and 17; and 17 is the applicable rule at overlap.

Hello Curtis,

The rules involved are:

When the boats are not overlapped - rule 12 - the boat clear ahead is ROW
When the boats are overlapped - rule 11 - the leeward boat is ROW

As you can see, the ROW changes instantly at the moment the boats become overlapped.

A short definition of when boats are overlapped - when neither boat is clear astern of the other. See definition of Clear ahead - Clear astern in the definition section in the front of the rule book.

However, another rule begins to apply at the very instant ROW changes ( when an overlap is established.) - rule 15. Have a look at 15. When a boat becomes ROW by its own action (say by establishing a leeward overlap from clear astern) it must initially give the newly obligated boat (the windward boat) room to keep clear and thereby comply with its new obligation to keep clear under rule 11.

But the “initial” period leeward must give to windward does not last very long, just long enough for windward to respond promptly (like straight away) and sufficiently by manoeuvring and keeping clear. If windward acts promptly and keeps clear no rule is broken. If windward does act promptly and adequately but can’t keep clear, then leeward breaks rule 15.

Judges and umpires recommend sailors make or otherwise purchase little boat models with a moveable mainsail booms, small enough to carry in one’s pocket, that can be manoeuvred around on a table top to create hypothetical rules scenarios and thereby more easily study how the rules work in practice. It’s also good practice for when one has to explain a situation to a protest committee.

I also recommend studying the Definitions very carefully because these apply in all the rules in all situations and can’t be changed by sailing instructions.

I hope you find  this helpful., but never delay asking questions.       Phil.

Hi Phil very well explained.
 As member of protest committee or Jury I always carry a set of boat models. Found it useful, besides protests, for discussion of rules situations with young sailors. Kind of generates more interest as it is visually more appealing and facilitates understanding.

PS. Thanks John,

I neglected the limitation imposed by rule 17, which introduces the principle of proper course.

Rule 17 says;
If a leeward boat’s overlap was established from clear astern and within 2 of her boat lengths of the windward boat, she (the leeward boat) shall not sail above her proper course.

There is, as you might expect, a Definition of proper course. You’ll need to study the definition carefully to understand it properly, because there can be more than one proper course. But generally speaking its a course the leeward boat boat would sail to finish as soon as possible, and it’s the leeward boat’s proper course, not the other boats course.

So back to Curtis’ question. Let’s call the boat that was astern at the beginning, Yellow, and the other boat, Blue. 

When Yellow becomes overlapped to leeward, Blue must respond by keeping clear. (Rule 11). Yellow must “initially” give Blue room to keep clear (rule 15) and, if the overlap was established from clear astern and within 2 lengths, Yellow may not sail above her proper course (rule17).
If Yellow sails above her proper course after establishing the overlap, Yellow breaks rule 17, and If after the rule 15 “initial “ room period finishes Blue fails to keep clear, Blue breaks rule 11 with no exemption available under rule 43.

Phil.

.In addition, Yellow must initially give Blue room to keep clear and comply with
                              Yellow must comply with rules 12, 15 & 17
                              Blue must comply with rule 11
           

And I would add that 11 and 17 can be infringed at the same time since 17 can be infringed by Yellow even if Blue is not affected by her change of course and 11 can be infringed by Blue if she does not keep clear of Yellow even if she is sailing above her proper course.
Which is not the case with rules 11 and 15 since if Yellow infringes rule 15, then Blue is exonerated from infringing rule 11 by rule 43.1(b).
JPvC

Very good! Covers the scenario and also the ancillary complexities. Proper Course was the intangible as the winds were light and variable giving the leeward boat an advantage using prompt and proper trimming.

Great idea Tribhuwan Jaiswal to have a set of boats for demonstrating. I found a magnetic set that will do well.

Jean-Pierre, re: “.. since 17 can be infringed by Yellow even if Blue is not affected by her change of course..”

Yes.  To put some meat on the bones here,  can you share some examples where a boat was penalized under 17 for sailing above their PC but when they did so they had no effect on the other boat?

In the protest room, the jury has established the following facts :

· boat L, faster than boat W, establishes an overlap at a boat length to leeward of boat W.
· boat L lufs above her PC.
· boat W does not respond claiming for boat L to sail her PC.
· boat L bears away and avoid the collision.
· both boats protest.
· none takes a penalty.
Conclusion : boat L infringed rule 17; boat W infringed rule 11.
Decision : both boats are disqualified.
JPvC

In this case, Boat L maintained PC without luff.
Boat W incorrectly claimed ROW after overlap was established and drifted down on boat L causing contact.
Boat L bared off to accelerate and avoid further contact.

Hey Curtis,

In your example above, leeward should have born away to avoid contact and so avoid breaking rule 14 - which she may have done if she is adjudged by a PC to have not acted to avoid contact as soon as it became clear that windward was not keeping clear.

This is the value of using the little models, setting them up and asking one self; what if? And slowly going through the rules applicable to the situation as you move the models around.

Cheers,     Phil.

Thanks Phil.
 It's unfortunate that a boat could take an action causing a Rule 14 infraction after they should know that they will certainly be protested out for their own previous actions.

We are going to go with a white board and boat shaped flexible refrigerator magnets that also work with white board markers.

Interesting and informative conversation.

I think the discussion has gone beyond the intent of rule 17. 17 says that: If a boat clear astern becomes overlapped to leeward within two of her hull lengths to leeward of a boat on the same tack, shall not sail above her proper course while they remain on the same tack and overlapped within that distance, unless she promptly sails astern of the other boat. Here the proper course for the lee boat is to stand clear of the windward boat.  When the overlap was established to leeward of the clear ahead boat, the lee boat gave up her rights as leeward boat and her proper course to the mark is not relevant. Rule 17 allows for this in providing the leeward boat to sail astern the other boat to reassert another course.    

John Wade, re: “Here the proper course for the lee boat is to stand clear of the windward boat.”

Your reply highlights an important point to understand when evaluating a rule that uses “proper course”.

Def: “Proper Course” [emphasis added]
“A course a boat would choose in order to sail the course and 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 coursebefore her starting signal. ”

Rule 11 doesn’t use the term proper course. If we are talking about Rule 17, then when analyzing what the leeward boat’s proper course would be that she can not sail above, you must remove the windward boat from the scenario.  
 
If the windward boat was not there, what course could leeward be reasonably sailing to finish as soon as possible?

WOW!  Thank you Angelo. I have been sailing for years thinking the windward boat was free of harassment by a lee boat coming from clear astern; but I can see that the subtlety of the definition does not provide that freedom.  So, what is the intent of Rule 17, if the lee boat has lost none of its rights, and can go anywhere it chooses, claiming proper course? I can see a boat sailing an asymmetrical spinnaker, intentionally sailing below a boat with a symmetrical spinnaker for the sole purpose of sailing high to collapse the windward boat's spinnaker, claiming proper course.  And why would the the rule provide the "...sails astern of the other boat."  clause if there is no restriction on the lee boat?

John.
WS Cases 7, 13, 14, 46 and 134 are authoritative interpretations of the racing rules and are worth reading when trying to understand how a rule works. 

Canada Appeals CAN8, CAN39, CAN50, CAN54, US Appeals US4, US13. US70 and RYA Cases , provide valuable insight, although not authoritative interpretations. Remember they are written by the same people who listen to the appeals, so good luck ignoring an MNA Appeal or Case.

John, speaking from an asym racer POV, if I’m overtaking a sym boat from clear astern, the last place I want to be is below her, unless im trying to establish an inside overlap before the zone or unimpeded for my next gybe soon to come.  I’m usually yelling “I’ll be past you as quickly and painlessly as I can!!” and head to windward.

That said, addressing your scenario, remember RRS 17 does not apply until there is an overlap to leeward from clear astern.   Before that, a faster, overtaking asym can sail whatever course she likes as long as she keeps clear of the sym boat ahead.

Also, depending on the wind range, an asym boat can have a very wide range of sailing angles with nearly the same VMG. 

So, as you suggest, an approaching asym boat might decide that she’ll sail lower than her optimum course while approaching a sym boat to establish an inside overlap, and then head up to her VMG course after the overlap. 

The thing to remember is that, when looking at RRS 17, it is the leeward boat’s proper course that is the measure, in the absence of the windward boat, only after the overlap is established. 

The subtle point that Jean-Pierre is making is that RRS 17 does not convey any rights to the windward boat, RRS 17 only limits the leeward boat. Therefore, if you are the windward boat and think a leeward boat is sailing higher than her RRS 17 limit, let her and then protest.  DO NOT PREVENT THEM IF YOU HAVE THE ABILITY TO KEEP CLEAR . 

You are still obligated to keep clear by RRS 11.  Your option is to protest them and make them justify their course before a PC if you think they are sailing too high. 

Thank you all for the clarification of Rule 17. As I said earlier I have always thought lee boat rights were suspended under Rule 17, and that the lee boat's proper course was that of the windward boat, and that lee boat must stand clear of her.  So, what is the reason of the requirement to pass astern the windward boat if the leeward boat has lost none of her rights?

John re: " ..what is the reason of the requirement to pass astern the windward boat if the leeward boat has lost none of her rights?"

See the pic below.  As Jean-Pierre inferred in his example, Blue is sailing above their proper course at #3, but in this different scenario, Blue does not break RRS 17 because she promptly takes the stern of Yellow.

... and while I'm at it, here is Jean-Pierre's scenario in picture form where Yellow stands firm and Blue does not take Yellow's stern.

A leeward boat is entitled to luff to her proper course, even when she has established a leeward overlap from clear astern and within two of her hull lengths of the windward boat. If rule 17 applies to the leeward boat when she luffs above proper course she breaks rule 17. At position 3 Yellow luffs above proper course and passes astern of Blue. Green luffs above proper course and does not pass astern of Red. Green breaks rule 17, Yellow does not.

Thank you Mark.  You are saying the same thing I said. The diagrams you presented appear to me show the proper course for both boats to be that of the windward boat.

John, I don't agree with your interpretation. I would encourage you to read WS Case 46 and Case 14.

A leeward right-of-way boat’s actions are limited by rules 16.1 and 17. The leeward right-of-way boat is entitled to luff to HER proper course, even when she has established a leeward overlap from clear astern and within two of her hull lengths of the windward boat. The windward boat must keep clear under rule 11, even if she has to sail above her proper course.

Yes, Mark I fully agree with you. As soon as W does not respond to any luff of L, she is infringing RRS 11 as keep clear boat. She cannot be exonerated even if she can demonstrate that L was sailing above her proper course. In any case, W has to keep clear of L, that's the basic rule 11.
Your drawing is perfect : on the left, Yellow is not infringing 17; on the right, if Red and Green have the same proper course, then Green is infringing 17 in position 3 but, in the next position, Red should be luffing to be keeping clear of Green otherwise rule 11 would also apply.

Thanks Angelo for your last drawing; Yellow is infringing RRS 11 but, since Blue, leeward boat, is sailing with a gennaker while Yellow has a symmetrical spinnaker, Yellow will have a great difficulty to prove that Blue was sailing above her proper course. If your drawing his validated during the hearing, Yellow will be DSQ for infringing RRS 11 and no penalty on Blue.

Thanks Jean Pierre .. yea .. I tried to merge your description with John's sym v asym scenario and it was a bit of a stretch.  

I agree (and as I mentioned to John previously), asym's can have a broad range of True-Wind-Angles's with very similar VMG's.

Thank you all for your comments and wisdom. I will hence forth assume leeward boat has ROW regardless of Rule 17. However, can someone explain the purpose and intent of Rule 17? Why is it even addressed in the RRS if it has no authority?

John, Rule 17, On the Same Tack; Proper Course is one of the rules in Section B General Limitations. The rule limits the course a leeward right-of-way boat can steer. The rules writers decided that it was a bad idea to allow a boat to gain a leeward overlap and luff the windward boat head to wind.

When considering how the rules apply it is important to consider all the rules that might apply, and then apply those that do. Begin with the Right-of-Way rules in Part 2, Section A, then decide if any of the General Limitations in Section B apply, as well as the exoneration rules in Part 4, Section A (see rule 43, Exoneration).

 

Thanks again Mark.  I have read through he cases recommended, and can see that there are other sailors who interpret Rule 17 same as I, and some race committees as well.  Maybe another look at Rule 17, in four years would be in order, to clarify or make it more easily understood.  It is at present too subtle, too clouded with perceptions not intended. I really enjoy these forums and learn a lot from them. Thanks to everyone participating.