I want us to focus on position number one.
And I appreciate your patience as I continue to consider this case.


Blue's proper course is TACK, so the definition of Mark-Room Room is off.

Mark-Room Room for a boat
(a) to sail to the mark when her proper course is to sail close to it.....

Then, Red has the right of way under Rule 11 and DOES NOT HAVE TO GIVE Mark Room to blue.
...... so in position N°1 rrs-18 WOULDN'T APPLY ?

18.1 When Rule 18 Applies
(a) Rule 18 applies between boats when they are required to leave
a mark on the same side and at least one of them is in the zone.

Robert "My review of RRS 86.1(a) indicates no issues with this change."

An argument against that assertion might be that 86.1(a) forbids changes to rules of an appendix that changes Part 2 and Def's and that doing what you suggest .. in effect ... changes those Appx-rules by inserting a "however-clause" exception and then inserts the starboard language.  

What I am saying is that it is more complicated than simply having a gravitational force component parallel to the local surface of the water.  Surfing, as a general phenomena, is defined and understood.  Where it isn't defined is in the RRS.  Unfortunately, this forum is not the place for the very long and very deep dive explaining the physics of surging, surfing, and planing.  But to me, the take away is that we need to understand the difference between surging, planing, and surfing and when each of these is possible to be able to properly interpret and apply RRS 42.

Wow Paul ... that must have been a lot of work (and moving forward as the working out the kinks phase begins). 

Congratulations!

Ang

Thanks Ben ... yea .. you asked how the reasoning would go and I obliged :-)