Assuming that mark is to be left to starboard, as it appears to have been drawn, rule 18.3 does not apply. If you mean they are both going to "shoot" up to pass the mark to port, I'm not sure that's even possible based on the drawing. But, under those circumstances, I don't think rule 18 really is in play. Once blue is leeward she can luff up to round the mark. 18.3 doesn't apply because yellow did not enter the zone on Starboard fetching the mark.

Hi Catalan, I agree with Anthony - as it appears the Mark has to be left to starboard. The one rule that could be in play is rule 13 - blue has to keep clear of yellow while tacking.  A bit more of a description always helps for people to judge the situation as you picture it. 

Blue’s original mark room ends when Yellow passes HTW and they are on opposite tacks R 18.1a(1).

Yellow may break R 13 as she tacks.

Blue is subject to R 13 while she tacks.

It may be possible for Yellow to head-reach around the mark without tacking, and so R18.3 could apply when Blue tacks – but we do not know yet.

R 18.2(a)(1) does not apply after the tacks as the ‘reaches the zone’ is not satisfied.

To me, the question is whether R 18.2 (c) is turned on after Blue completes her tack? As neither boat appears to be fetching the mark, it makes no sense to try to apply R 18 – just the rules of Part 2.

John

I'd bet dollars to donuts that our friend Catalan's intent is that he wants us:

You may be right, Angelo. I included that possibility in my post. But even if yellow qualifies for "fetching," the other requirement of 18.3 is not met (she didn't enter the zone on Starboard). 
So, 18.3 would not apply. 

Anthony re: "the other requirement of 18.3 is not met (she didn't enter the zone on Starboard). So, 18.3 would not apply. "

That is an important change in the wording of 18.3 in 2025.  In the other recent thread I wrote it out in this comment.

If you conclude that Yellow is fetching the mark, then 18.3 applies in Catalan's scenario, it's just that Yellow is not entitled to MR from 18.3(b).

The significance of the new wording for 18.3 is that when it applies it turns off all of 18.2.
So my question is that if we conclude that if Yellow is not fetching the mark, and the conditions for 18.3 do exist and it does not apply and so does not turn off 18.2, then do the conditions exist that turn on 18.2(c) and grant mark room to Blue (as soon as she passes HTW to stbd).

John

Position 2 is ambiguous as to which hull broke the plane of the zone first. Blue is still clear astern yellow, even in position 2. However, yellow has gone through head-to-wind inside the mark. We don't really know if either boat is accelerating or slowing down. Port rounding -- yellow is short of the mark, so NOT "fetching" proper course. Starboard rounding, so it looks like an emeregency tack to try to salvage the mark and without giving the blue time to respond (we don't know if there was any communication), both could be guilty of any number of transgressions, and like so many of these speculative adventures would depend on testimony at the protest.

Yes, I agree, Angelo. I was not clear in my statement. We are making a lot of assumptions about what the OP really meant. Yellow could be said to be fetching if she doesn't have to tack to round (not at all clear from the diagram, but let's assume she can do so). 
In that case, rule 18.3 states that 18.2 does not apply. Blue is not entitled to mark room. However, once the tack is complete, blue is leeward and would have luffing rights. 18.3 a and b do not apply because yellow did not enter the zone on Starboard. 
The way I interpret the new rule 18 concerning tacking in the zone is that

Anthony .. on your 1,2,3 .. with my suggested [additions] and subtractions ...

Joseph .. being only 1/2 BL below the layline, there is the possibility that Yellow could use her speed/momentum to get around the mark without changing tacks.   I think many judges would be satisfied that Yellow meets the definition of fetching at #3.  Is she "clearly fetching"?  No. 

If she was a full BL below or greater, IMO then that's more clear that she is not fetching.  It's a grey-area judgement call.

I think there is a basic misunderstanding in your posts. There is NO requirement in the first part of18.3 that the stbd boat has to have entered the zone on stbd; only that one of the boats is on stbd and is fetching the mark. That stbd boat could have tacked from port inside the zone. Having been on stbd since entering the zone only applies to the IF section that activates 18 (a) & (b).

Robin .. whose posts is your comment directed to? - Ang

EXACTLY ANGELO!!
YOU READ MY MIND

I'd bet dollars to donuts that our friend Catalan's intent is that he wants us:

Isn't it as simple as - both boats enter on port tack into the zone - so their is no other boat on starboard tack.... as 18.3 requires. So it boils down to rule 18.2 not being intor effect for neither of them. Rules 10, 11, 12, 13 and 15 will apply for what continues. There is no Zone, there is no 18.2 - both are tacking in the zone and turning 18.2 off. 
From the picture it appears as Yellow made a clean tack to starboard, Blue has to give RoW. Blue is entitled to luff Yellow when overlapped. But Blue cannot tack.

That is how I see it now if the mark is to be left to Port