Walt wrote:

o Rule 18 now applies in some circumstances when both boats tack
around a mark. (the current rule states that if the proper course
for either boat is to tack, rule 18 is out. The new rule says one
but not both.) I think this needs to be read carefully, because
at first read it appears to say more than it does. My initial
take is that this change only makes a practical difference in a
situation where two boats are on opposite tacks and the proper
course for both of them is to tack. This would seem to be an odd
occurrence (i.e. boats in different races that share a common mark).
I welcome more discussion on this - I'm not sure I've read it
correctly...


Where there would be a change is where both boats are on starboard
tack (at a leave-to-port windward mark) and neither boat can fetch the
mark. Under RRS 2001-04 rule 18 cannot apply since both need to tack.
Under RRS 2005-08 rule 18 can apply since both must tack. This is an
inconsequential change in my view.


I don't follow your reasoning here. Since both boats are on
starboard, they're not on opposite tacks. I don't see any changes to
rule 18 at all that affect overlapped boats on the same tack.

The reason for the change was a rare situation at leeward marks. Two
boats enter the zone on port but the only proper courses for the next
mark require both to tack immediately after passing the mark. Under
RRS 2001-04 wording rule 18 wouldn't apply even though except for the
tack after the mark it would be a typical rounding. Under RRS 2005-08
rule 18 will apply since both boats must tack to sail a proper course.

Again, you've lost me. Two boats enter the zone on port. What part
of RRS2001 says that rule 18 doesn't apply?

I lost you because I wrote too quickly and was WRONG. The situation is
relevant when boats are on OPPOSITE tacks, not the same tack (as you
pointed out). Sorry for the confusion.

The second clause of 18.1(b) is a bit obscure. The clause (when the
*proper course* for one or both of them to round or pass the *mark* or
*obstruction* is to tack) is intended to cover the situation where
boats are on a leg to a reach mark and one boat has misjudged the mark
(for example because of current) and must sail for a while on the
other tack in order to round. As a result, that boat will be sailing
in to the mark on starboard tack while the other boat is approaching
the mark on port tack and will simply tack around the mark. Since the
boats are not on a beat to windward, the first clause of 18.1(b) does
not apply and without the second clause rule 18 would apply.

See http://www.racingrules.org/misc/18-1(b)_2ndclause.gif

The problem some folks (not me) saw in the 2001-04 rule occurred when
two boats were coming in to a leeward mark (on OPPOSITE tacks) and the
only proper course for both boats was to tack immediately after the
mark. Since the proper course for both would be to tack rule 18
wouldn't apply between the boats at that leeward mark. NOT what was
intended but a somewhat rare circumstance.

[I will now point out the problem with the 2005-08 rule. If the boat
that misjudged the reach mark then misjudges the layline and tacks
short then both boats must tack (P once, S twice more) and rule 18
will apply between them. Not intended, but again a rare circumstance.]

Art Engel
e-mail: artengel123 (at) earthlink.net
Web: http://www.racingrules.org