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gordon View Drop Down
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Posts: 1037 		Post Options Post Options   Quote gordon Quote  Post ReplyReply Direct Link To This Post Topic: Proper Course
    Posted: 05 Dec 13 at 2:28pm
I really feel that we are making life too complicated. A boat, as far as the rules are concerned is a sailboat and her crew. I can find no reference in the rules to a boat including windshadow, bow wave, stern wave or whatever.

If there are no cases on a rule that is usually because there are few, if any, protests involving that rule.

In this case, if the leeward boat was that close to the windward boat I would be looking more at rule 16.1 than 17.

Windward boat is required to keep clear (even if rule 17 is on) and leeward boat is required to give room to keep clear if she changes course.

If windward could not keep clear while manoeuvering in a seamanike way then leeward has broken rule 16.1. If she can  keep clear all well and good and there is unlikely to be an incident to protest.
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Posts: 8956 		Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 13 at 8:34am
Sailing to the waves is what you would do whether the other boat was there or not. The only problem I can see with that is that you do have to give the other boat time to keep clear, and sailing to the waves is very time critical, so if they are a different class (maybe a heavier one, which makes less use of the waves) then communication could be rather vital if you want to keep sailing fast, rather than crashing into another boat.
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Andymac View Drop Down
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Posts: 852 		Post Options Post Options   Quote Andymac Quote  Post ReplyReply Direct Link To This Post Posted: 05 Dec 13 at 2:21am
Originally posted by Brass

The external wave would have come along whether the windward boat (that must have been there to get us into rule 17 territory in the first place) was there or not:  the change in conditions would have occurred in the absence of the windward boat, responding to the wave would be leeward's proper course.



Since waves have been brought into the discussion.

In the same context of apparent wind changes due to the windward boat, I would assume the same logic would also be applied to a change in sea state caused by the windward boat (i.e stern and bow wave)? This could be relevant in semi-planing/surfing conditions.



Edited by Andymac - 05 Dec 13 at 2:23am
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Brass View Drop Down
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Posts: 1151 		Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 13 at 6:43pm
Originally posted by sargesail

Originally posted by Brass

Originally posted by flaming

   It is surely always a boat's proper course to come up and try to fill their kite when it collapses due to a lack of wind.

Sorry, absolutely NOT.  A boat's proper course is what the Definition says it is

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.


So let's just say that there is a wave (nothing to do with W - some chump umpiring another race and driving too fast?), which slows L, bounces the kite, and that the response is to head up.


Absolutely no problem so far except that a CHUMP would never do that:  CHUMPS can do no wrong <g>.


You surely accept that from the moment the boat slowed it's proper course changed?


Yup.


The external wave would have come along whether the windward boat (that must have been there to get us into rule 17 territory in the first place) was there or not:  the change in conditions would have occurred in the absence of the windward boat, responding to the wave would be leeward's proper course.


Because your earlier call book example seemed to make proper course an enduring thing, but actually it changes moment by moment as the conditions change.


Certainly proper course can change moment by moment, depending on wind strength and direction, waves, position on the race course and so on.


If you're talking about the sample umpire dialogue I made up, it actually does give an example of wind lifting and proper course changing.


Taking that on - what if the trimmer over eases the sheet and the boat slows, before L enters the windshadow....At that point the course that meets the definition includes hardening up to bring the apparent forward.


Yup.


Not a problem:  that's what the boat would have done in the absence of the windward boat.


Consider also the example of a close hauled boat passing to windward of both boats:  she would cast a wind shadow, and responding to that wind shadow would be quite ok:  the close hauled boat is not involved in the rule 17 situation ('referred to in the rule') and that's what the leeward boat would have done if the windward boat had not been there.


The problem only arises when the leeward boat responds to a change in wind speed or direction that would not have happened if the windward boat had not been there.

Originally posted by sargesail

Originally posted by flaming

Imagine a boat with an autopilot set such that it always steers the best course by its polars.  You would agree that in open water this boat is always steering its proper course.  But if this boat overtakes another boat to leeward the clever autopilot, which knows nothing of the existence of the other boat, will heat up when the blanketing effect hits.  

I would argue that it's still sailing it's proper course as it's still just trying to sail to polars with respect to the wind hitting the boat, .

How do you account for this?

The 'blanketing effect' would not be there 'in the absence of the other boat'



Edited by Brass - 04 Dec 13 at 8:35pm
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Posts: 1151 		Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 13 at 6:16pm
Originally posted by sargesail

It's only clear cut if you take the boat to include it's wind shadow - that's a big step.  

Originally posted by flaming

But my boat with its autopilot is still sailing the course it would take to get to finish fastest in the absence of other boats.

It only isn't if you take the wind shadow to be part of the other boat.  Which is a new definition on me.  I don't see anything in the rules that defines a boat to include her wind shadow.

Originally posted by sargesail

Brass - to me it's you that is adding something not us.....you are extending 'the boat' to be the boat and it's wind shadow.  

Originally posted by andymck

The wind shadow is clearly part of the boat. It has always been part of the rule. 

Guys, I have never said the wind shadow is part of the other boat.

That would be plain silly.

JimC has it

Originally posted by JimC

If the boat is there then its wind shadow is there. 
If the boat is not there its wind shadow is not there. 

The rule says the absence of the boat. 
If the boat is absent the wind shadow is absent. 

The wind shadow only exists because of the other boat.

It would not exist in the absence of the other boat.

Try this:

IF

The windward boat casts a [significant] wind shadow

AND

The leeward boat bound by rule 17, and previously sailing her proper course, sails into that wind shadow

AND

The leeward boat changes course to windward to respond to the lessening of wind in the wind shadow (and not any change in the prevailing wind)

THEN

The leeward boat has sailed above the course she would sail to finish as soon as possible, had the windward boat not been there (in the absence of the windward boat), that is, has sailed above her proper course.
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Posts: 397 		Post Options Post Options   Quote andymck Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 13 at 4:49pm
The wind shadow is clearly part of the boat. It has always been part of the rule. It can not be argued to exist in the absence of the boat that creates it.
This was never an issue until the use of assymetrics on displacement boats. We then started to hear the argument that rule 17 does not apply to me because I am an assymetric. I often used to give a copy of the rules to such skippers and ask them where in the book that exception was? The bottom line is this argument was just as invalid for assymetrics boats as it was for all other types of boat. The crux would be to look at the course before and immediately after, the Classic was the head low, hit the shadow, luff hard, then head low again. Quite clearly the luff was only there because of the windward boat. The bottom line is that the winners will keep well clear, on either side so they don't get luffed if they go to windward, or sail low enough to break through with minimum fuss.

Brass has this one spot on. There does not need to be a case, as the rules a very clear, and confusion only occurs when people try to add their own definitions or aww buts.


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jeffers View Drop Down
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Posts: 3048 		Post Options Post Options   Quote jeffers Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 13 at 3:58pm
Originally posted by flaming

My question is simple - when constrained by 17 can I luff to my proper (VMG) course for the wind as I experience it in the wind shadow of the windward boat?  


No because that is not your proper course as defined in the definitions section of the rules.


Edited by jeffers - 04 Dec 13 at 4:06pm
Paul
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rogerd View Drop Down
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Posts: 1076 		Post Options Post Options   Quote rogerd Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 13 at 3:24pm
Interesting discussion guys. Keep it going. I am no sea lawyer but I am with Jim C and Brass on this. The wind shadow would not have been there if the W boat wasn't there so luffing up to fill your kite would be above what your proper course would have been if the W boat and hence its wind shadow wasn't there.

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Posts: 41 		Post Options Post Options   Quote flaming Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 13 at 2:17pm
Originally posted by jeffers



It would be interesting to see the Facts Found by the PC as this is what they would have based their decision on.


This wasn't a pertinent issue to the recent protest, the facts found simply state "no evidence to suggest X sailed above her proper course"

Which was rather expected given the GPS track.

Ok let us break this down again....in to even simpler terms.

If Flaming is Clear Ahead or Clear Astern they can luff up to fill the spinnaker as they are not bound by the Proper Course restriction.

If Flaming was overlapped when they entered the wind shadow they may only luff of to theirproper course as the overlap was established from astern.

Is that clear enough?

So the questions to Flaming are:

1) Were you overlapped when you luffed up? 

2) If yes to number 1 did you luff above the course you would have luffed if your wind was not affect by the other boat?

If the answer to both is yes then you sailed above your proper course IMO.


There's no issue at all with the understanding of how 17 works.  

My question is simple - when constrained by 17 can I luff to my proper (VMG) course for the wind as I experience it in the wind shadow of the windward boat?  

Which seems to come down to "is the wind shadow part of the boat as referred to in rule 17?"
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Posts: 3048 		Post Options Post Options   Quote jeffers Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 13 at 1:49pm
Ok let us break this down again....in to even simpler terms.

If Flaming is Clear Ahead or Clear Astern they can luff up to fill the spinnaker as they are not bound by the Proper Course restriction.

If Flaming was overlapped when they entered the wind shadow they may only luff of to their proper course as the overlap was established from astern.

Is that clear enough?

So the questions to Flaming are:

1) Were you overlapped when you luffed up? 

2) If yes to number 1 did you luff above the course you would have luffed if your wind was not affect by the other boat?

If the answer to both is yes then you sailed above your proper course IMO.

It would be interesting to see the Facts Found by the PC as this is what they would have based their decision on.

Anyway.....that is enough entertainment for today, lets go sailing?
Paul
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