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SteveB00 View Drop Down
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Posts: 24 		Post Options Post Options   Quote SteveB00 Quote  Post ReplyReply Direct Link To This Post Topic: Proper Course
    Posted: 30 Nov 13 at 11:31pm
Hello.This is my first post here, and I'm looking for some clarification of rule 17. Here's the situation:

2 boats are broad reaching under spinnaker in consistent breeze, the faster boat (L) is clear astern and to leeward of the slower boat (W). L forms an overlap within two hull lengths to leeward of W and continues to sail faster than W until she is ahead, but still overlapped, at which point her wind becomes variable and light and her spinnaker starts to collapse. She responds to this by coming up.

Is this a proper course? L would argue that, even in the absence of W, had the wind become variable and light, she would have responded by coming up (to create more apparent wind). W would argue that L's wind only became variable and light because of the affect of W's sails on L, so that, in coming up, L is sailing above a course she would have sailed in W's absence.

Who's right?

Thanks in advance,
Steve  = : ^ )

P.S. This isn't academic; it happened to me yesterday.
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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: 01 Dec 13 at 3:19am
Welcome.

You have obviously grasped the relevant concepts and issues in rule 17.

The solution to your problem depends on a matter of fact:  Was the change in apparent wind affecting L caused by W or not?

You described W and L broad reaching, presumably with AWA between 90 and 135 degrees aft.

You then say L sailed through W's lee  'faster than W until she is ahead, but still overlapped', so, presumably L gets about half a boat length advanced on W.

If boats were sailing hot, up towards 90 degrees AWA, I would be fairly confident that, at that time, if L was half a boat advanced on W, L was sailing in breeze that was not (or no longer) substantially interfered with by W, any change in wind strength or direction was not a result of W and luffing to maintain pressure by L was sailing her proper course.

OTOH, if boats were sailing deep, at 135 or more degrees AWA, W's wind shadow will be projecting off her leeward bow and will probably still be having some effect on L, although, at half a boat length advanced, L's headsail should be in clear air.

If W brought evidence to a protest hearing that she observed the breeze was consistent in strength and direction throughout, then the protest committee might infer that any change in wind experienced by L was as a result of W, and that here change in course would not have been made in the absence of W.

OTOH, if W could not bring strong affirmative evidence that the wind remained steady, and L gave evidence that it changed and weakened, then there would be a good chance that the protest committee would accept L's version and conclude that her luffing was what she would have done in response to a wind change in the absence of W.
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SteveB00 View Drop Down
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Posts: 24 		Post Options Post Options   Quote SteveB00 Quote  Post ReplyReply Direct Link To This Post Posted: 01 Dec 13 at 3:46am
Thanks for the thorough reply. I think we can be confident that, at least in some measure, the weakening of L's wind was due to the presence of W, and that I owe someone an apology. :-[

Thanks again,
Steve  = : ^ )
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sargesail View Drop Down
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Posts: 1459 		Post Options Post Options   Quote sargesail Quote  Post ReplyReply Direct Link To This Post Posted: 01 Dec 13 at 9:20pm
Brass.

Interesting.  I have previously heard the definition:

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.

As applying to the boat itself, but not to its effect on the wind.  The way you express this does create seem to create some oddities:

1.  Clear astern approaching from position behind and to L with Assym, sails gradually converging course and becomes  becomes L, and is not permitted to respond to the change in wind direction....

2.  Yet Clear astern approaching from dead astern can bear away below proper course to avoid the obstruction and then return to her PC with a luff....

But I'll give you the fact that your last para is the relevant it - it would be for W to prove the wind was steady...
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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: 01 Dec 13 at 9:32pm
The question is, what was the course the boat would have sailed to finish as soon as possible if the other boat had not been there?

1.  There is nothing to stop L responding to any change in the prevailing wind.  What she cannot do is hot up in response to the decrease in pressure in W's wind shadow.

I'd normally expect W to let it slide if L got her nose in front and hotted up across W's bow, as long as L didn't interfere with W, (but not in match racing, particularly now the Elliotts have got Asys).

2.  No problem with L sailing below her proper course then coming back up to it.


Edited by Brass - 01 Dec 13 at 9:47pm
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sargesail View Drop Down
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Posts: 1459 		Post Options Post Options   Quote sargesail Quote  Post ReplyReply Direct Link To This Post Posted: 01 Dec 13 at 10:54pm
Originally posted by Brass

The question is, what was the course the boat would have sailed to finish as soon as possible if the other boat had not been there?

1.  There is nothing to stop L responding to any change in the prevailing wind.  What she cannot do is hot up in response to the decrease in pressure in W's wind shadow.

I'd normally expect W to let it slide if L got her nose in front and hotted up across W's bow, as long as L didn't interfere with W, (but not in match racing, particularly now the Elliotts have got Asys).

2.  No problem with L sailing below her proper course then coming back up to it.

Sorry I still don't follow how the interpretation in point one follows from the defintion....she is not hotting up because the other boat is there - she is hotting up because the wind has decreased.

Off to the Call Book now!
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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: 01 Dec 13 at 11:00pm
If the prevailing wind decreases fine.

But if the wind L experiences is lessened because it is in the wind shadow of W, then the there would have been no decrease in wind 'in the absence of the other boat'.
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sargesail View Drop Down
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Posts: 1459 		Post Options Post Options   Quote sargesail Quote  Post ReplyReply Direct Link To This Post Posted: 01 Dec 13 at 11:18pm
Brass,

I understand what you're saying, but had previously understood another interpretation to be the case.....that it applied only to the boat and not to its effects.

I don't see how L - who may not be able to see wind and water to windward of W is expected to be able to say it is not a lull in the wind.

How would you make a call as an umpire?  The Call Book is no help.  Might need to be given Assyms on Elliots!

Bed time so not going to look at Cases just yet.
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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: 01 Dec 13 at 11:51pm
Umpires are supposed to have decided what the proper course for both boats is at the beginning of the leg.

Umpires Manual
E 12 Proper Course
Downwind protests involving proper course are common. It is therefore essential for
the umpires to establish the boats’ proper courses as soon as possible after they
begin their downwind leg. Observing the masthead wind indicator and the angles at
which both spinnaker poles and main booms are being set all give a good guide.
When the boats are gybing downwind it is also essential for the umpires to be aware
of the angle to the next mark (or finish line), as this may dictate when a boat must
gybe to avoid sailing above its proper course.

Proper course falls into the same category as head-to-wind, mark touching and early
pre-start entry: accurate judgement can be difficult (and at times impossible) so
penalties must be given only when the breach is clear-cut.

You would tend to assume that W was sailing the proper course, and if W (and L) were sailing deep of what the umpires thought their proper course was, the umpires should have noticed it.

Dialogue might go like this:

Give Astern.

Agree, if you hook me 17 will be on.

Agree.

Right Leeward, 17 on.

Agree, keeping clear, You sailing your proper course?

Negative.  I'm deep of my proper course, I can come up

Agree

Luffing, giving room

Luffing, keeping clear, I'm above my proper course, 17 on you

Negative, Wind has lifted

Agree, I'm Give Windward, on proper course, 17 on you

Agree

Luffing, giving room

Luffing, keeping clear, above my proper course 17?

Agree, I'm above proper course

Y Flag on W

17 Penalise L
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JimC View Drop Down
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Posts: 6662 		Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 02 Dec 13 at 8:17am
Originally posted by sargesail

to be the case.....that it applied only to the boat and not to its effects.


Never ever heard that one, and to me it seems a very very strange idea. My answer, I guess, put brutally, is that if you don't know where the wind shadow's going to be you should not be pushing the rule so hard. I'd say that if W hasn't slowed the wind hasn't dropped ought to be a reasonable guide.

I wonder who spread such a bizarre corruption of the meaning of the rule?


Edited by JimC - 02 Dec 13 at 8:21am
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