Rule 17 and the definition of proper course

Originally posted by Presuming Ed

Originally posted by Presuming Ed

Originally posted by jeffers

They could argue whatever they like, the definition of Proper Course is 'in the absence of other boats' so PW's actions are immaterial. 

[Pedant hat] Minor point, but it's "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 take this scenario below, and saying that 17 applies between yellow and blue. When determining yellow's proper course, we can "remove" blue and see what that does to yellow's course. But yellow's proper course is to avoid green, so even though she sails higher than before, she doesn't sail higher than her proper course, and doesn't break 17. 
[/Ph]

Seeing as how we've got our pedant hats on, Y's obligation is not to 'avoid' G.  It is to keep clear of G.

But Y's proper course is not only the course necessary to keep clear of G:  it is the course she would sail to best speed.

Y could sail somewhat hotter than as illustrated so as to avoid turbulence from G (or indeed, to avoid tempting G to luff aggressively), and that would still be her proper course.