Q1 After calling you tack the windward boat is responsible.
Q2 She had room to tack and tacked. Then sh became windward boat and should keep clear, this is after the tack so no exoneration.
Q3 se before here no problem.
Q3a room is to tack not to get to a close-hauled course.
Q3b no she must proceed in a seamanlike matter the essence of Room.

Hi Angelo,
is it also worth adding a question about what room to tack means? 
Is it room to start to tack ie to pass htw? 
Or is is room to complete the tack to a close hauled course?
John

Room to tack is to tack, that is pass head to wind.
No right to go down to a close-hauled course.

Tack as a verb is not defined.  Rule 13 gives a clue, 'while tacking' is after passing head to wind until on a close hauled course.  If room to tack is only room to pass head to wind, that is little different to luffing to head to wind, which yellow could do without recourse to rule 20.

Here is a variation. The question is " Did Blue give Yellow room to tack"?

Oxford dictionary
Tack
an act of changing course by turning a boat's head into and through the wind, so as to bring the wind on the opposite side.

Nothing about close-hauled course.

I think these questions illustrate the need for a defined term: "Coming about". I think we discussed this before as well, and this sorta solidifies it.

IMO, room to tack includes room to come all the way through the tack to close-hauled. If it were just room to cross head-to-wind, it wouldn't be much better than the leeward boat just going up to HTW to begin with.

Also, I will repeat my comment that RRS 20 is to make racing more fun and fair, and isn't really about safety, as most of the time, the leeward boat could simply slow down or luff up and accomplish the same safety goal (but would be losing ground to do so).

I totally agree with Niko.

I think “tack” is a nautical term and we should consult sailing texts and sailors before going to a dictionary.  Unfortunately I haven’t found anything quotable from sailing books.  I think the best approach would be to ask a large number of sailing instructors what they mean when they teach their students how to tack.  I’m pretty sure it would be something like “a maneuver that takes a sailboat from close hauled on one tack through head to wind and down to close hauled on the other tack.”

I’d also like to note that “tack” is used in rule 44.2. It defines a one turn penalty as “each turn including one tack and one gybe.”  If the turn had the gybe first then by Michael’s definition, the penalty would be complete upon passing head to wind. I don’t think that’s generally accepted but have seen no authoritative discussion.  I have seen videos of radio sailing windward marks where a port tacker crash’s the starboard tack line-up, breaking rule 10 and then spins into a gybe, briefly passes head to wind and then pops back onto starboard and carries on.  I don’t think that should be allowed but with no definition of “tack” as a verb who’s to say.

 
Revision: I guess the rule 13 title does imply that, nautically speaking, bearing away to close hauled takes place “while tacking” even though the title is not a rule.  I’d still like the first half of a tack to be included in a definition.

When Yellow hails for room to tack, she is saying that she understands that under R 13 she will be the keep clear boat after passing HTW until reaching close hauled but cannot do it unless permitted under R 20. In addition, Blue, by following R 20.2 and hailing ‘You Tack” is saying that she will not interfere with Yellow while Yellow is subject to R 13. 

My conclusion is that room to tack is using the R 13 concept of ‘beyond HTW until close hauled’.

John

Before going to the dictionary, so you could check it. 
I was at a merchant navy training school for five years.
It was there in seamanship classes we were told what a tack is.
There were no implications because there were no applicable rules.
It is putting this in rrs that causes a problem for some, but I have never experienced it.
I f the rrs  does not define, is the default not what I have done?

What of the gybe, wind from one side to the other taking the stern through the wind.

In fleet racing no need for the sail even to be full.

I disagree 13 just defines when rrs deems you should keep clear.
If It did not do this rights would change earlier.
Consider
Tacking to starboard
Or tacking in front of another boat.
13 is neded to push back a change of row.
And switch off 10 11 and 12.

First, nice job Ang for pursuing this.

I have my own opinions on each question answer. But they have already been given in one form or another in this thread. So no need to repeat. 

It does seem that there are multiple valid interpretations / meanings of the word 'tack '.  (Such is the beauty of the English language.) Yet, we only want only one.

Then a learned opinion (Q&A) or even a definitive interpretation (casebook case) may be needed. 

When two possibilities are about equally plausible, a focusing will only go so far. Have we reached that point yet? 

Definition of port tack is that the wind is on her port side. Tacking is therefore a split second while the boat is head to wind (neither port or starboard tack). Consider a leeward boat doing a hard luff to windward. A windward boat must keep clear but if the leeward boat reaches head to wind it is tacking and must keep clear.
I am advocating that tacking is a slit second and does not last from close hauled one direction to close hauled on the other. However to avoid doubt and protests it seems good to have your main setting on a particular side to prove the wind was on the opposite side and the tack was complete. This is a lot higher than close hauled.
Note rule 20.2(c) provides not only room to tack but adds “and avoid her” (also in 20.1)
So to relate to the questions in this thread:
1. John’s question, blue did give yellow room to tack but probably not “to tack and avoid”. Avoid does include room to dip
2 Angelo’s questions:
      1. Blue failed to give room to tack
       2.  Blue did give room to tack and also gave room for yellow to avoid her (by luffing)
       3. Same as 2
       3a. Yes
      3b.   No, or at least not from close hauled starboard to close hauled port. Yes, for the split second she is actually tacking
On the seamanlike reference, I note that luffing head to wind is common practice (eg start line or windward boat keeping clear) so a normal sailing practice, not unseamanlike.

In the diagram for Questions 2, Yellow still has some room before reaching the obstruction. What obligation does Yellow have to time her tack to keep clear of Blue? There is plenty of room for Yellow to time the tack to avoid Blue. Blue's hail of "You Tack" clouds the issue, as she should have just tacked. Now there is the expectation that Blue need to keep clear. Never the less, I don't see how the expectation that Blue must keep clear absolves Yellow of her obligation to keep clear of other boats until she is on a close-hauled course.

I do find it extraordinary that there is a view being expressed hear contrary to every thing I have ever heard on this subject, which removes any need to have a Rule 20!

But I also agree that the RRS need a definition.  And I would suggest that it should follow from Rule 13.

It's fascinating isn't it Matt?

I almost added to my last post another possibility...

The notion that it really isn't an issue.

Consider this:

There are two valid interpretations. Both work, and generally fit into the rule book.

If Sailor A's Club applies interpretation #1, and Sailor B's Club B, 8000km away applies interpretation #2, it is plausible that a SailorA could go a lifetime using  Interpretation #1, never considering the alternative.

Even Sailor A goes to Club B and races, but there is not an incident which raises this topic. He goes home having enjoyed the event thinking nothing of it. It goes like this for years. 

Is there a problem which needs fixing?

Then as the Internet use becomes more prominent, 8000kms separation fizzles into irrelevamce.

Sailor A and Sailor B one day meet in an internet chat forum, proposing the other has been wrong all their lives. Is there a problem now?

Is it worth the time effort and already 260 page casebook real-estate to fix this issue? That's for the rule-makers to decide. Perhaps not.

OK, the rule-perfectionist in me would like this resolved from top down. But, I do wonder what the chance of this landing on my protest desk is.

Incidentally, some people have mentioned the need for a new 'definition' of the verb 'to tack'.

As I see it, definitions are used to deviate/specify a word's meaning for RRS use from general/nautical use.

Our problem is multiple valid interpretations (simply, is it the complete move or the action of passing HTW?) - so casebook, not a definition.

I find the examples somewhat strange as blue responded "you tack" when they had no need to do so.  As it appears they were intending to tack, then all they needed to do was tack in a timely manner and then Yellow would tack to follow them.

Typically a boat responding "you tack" would duck rather than tack.
 

I went back to the Case book and looked at Case 35. To me, it is clear that when a boat hails for room to tack and the hailed boat responds you tack, the hailing boat can tack from a close hauled course on starboard to a close hauled course on port (or visa versa) and avoid the hailed boat. The case uses "seamanlike way" when it discusses the hailing boat avoiding the hailed boat. So in the example #1 and #2 originally proposed, Blue did not met her obligations under RRS 20.2(c). Example #3, Blue did.

The 1993-1996 rules had a definition for tacking and close-hauled:

Tacking  A yacht is tacking from the moment she is beyond head to wind until she has borne away to a close-hauled course.

Close-hauled  A yacht is close-hauled when sailing by the wind as close as she can lie with advantage in working to windward.

The 1997-2000 rulebook included many updates. The definitions tacking, close-hauled and gybing were removed.  Rule 41 in the 1993-1996 rulebook became Rule 13 in the 1997-2000 rulebook.  Rule 13 describes the restrictions on a boat while tacking and releases those restrictions when the tacking boat comes to a close-hauled course. 

Yes we all have to follow ws definitions. When they are at variance with the accepted definition it is good they are removed. Rules like 13 which defines when you get row back are good. The rule title is bad.

Regarding the claim that Rule 20 only lets a hailing boat sail just past head-to-wind, and not to close hauled, here are some thoughts.

Definition of Room:

When Rule 20.1 is invoked, the hailing boat is asking for room, i.e., manoeuvre in a seamanlike way. If a hailed boat only lets the hailing boat head up to just past head to wind, and not close-hauled, the hailing boat will eventually begin sailing backwards, lose control, and possibly collide with the obstruction they were trying to avoid and/or another boat.

I'm struggling to see how sailing backwards, out of control, is seamanlike.

Common usage of Tack:

Much of this hinges on the definition of the verb "to tack", it may be beneficial to examine the common usage of the term by actual sailors, and not just imprecise dictionary definitions written by non-sailors. Looking at the search results for how to tack a sailboat, every video and description has the boat ending on close-hauled on the opposite tack. None of the videos has the boat ending up a past head-to-wind.

So, from that, the common usage of the term "to tack" indicates that the tacking maneuver ends with the boat on close-hauled, not just past head to wind.


Rule 14 and Rule 20:

Looking at John Ball's fourth example, when Blue holds starboard and forces Yellow to turn back to their obstruction, that seems to be a violation of Rule 14.3: Blue is causing contact between Yellow and the obstruction (e.g., a pier) that "should be avoided".

So, even if someone ignores common usage of the word "to tack", only letting a boat go one degree past head to wind is a violation of Rule 14.3, assuming Yellow couldn't reliably duck Blue.

Intent of the rules:

This is admittedly a fuzzier argument, but there is the intent of the racing rules. Rule 14 indicates the rules' intent to minimize contact between boats and objects to be avoided. 

If Rule 20 only gave a hailing boat to go one degree past head to wind, and presumably hold that heading as long as they could, they would soon drift backways, lose control, and then either make contact with whatever they were trying to avoid, or another boat on the course. That appears to contradict the intent of the rules as indicated by Rule 14.

Perhaps there is a case that sheds more light on this?

Look take rrs out ot this they have their own agenda.

To tack is to change from the wind on one side to the wind on the other, period.

Same as I have said for gybe 

Anything else is ws confusing reality.

Rrs 13 is explicit and useful.

DO NOT CONFUSE THE REAL DEFFINITION WITH WS USEAGE 

mike