Oppostie Gybes, leeward Mark

Relevant parts of Rule 18.2 states:
Giving Mark-Room

(a) When boats are overlapped the outside boat shall give
the inside boat mark-room, unless rule 18.2(b) applies.

(b) If boats are overlapped when the first of them
reaches the zone, the outside boat at that moment shall
thereafter give the inside boat mark-room.

Ok so what else do we need to know, Mark Room:

Room for a boat to sail to the mark, and then room to
sail her proper course while at the mark. However, mark-
room does not include room to tack unless the boat is
overlapped to windward and on the inside of the boat
required to give mark-room.

and the important piece in this is proper course,

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 to help with deciding what a boats proper course is at
a leeward mark where it might gybe the ISAF made 18.4

When an inside overlapped right-of-way boat must gybe at
a mark to sail her proper course, until she gybes she
shall sail no farther from the mark than needed to sail
that course.


The way that I read all of this is, as a assy boat on
stb, coming in hot, I can sail no further from the mark
than to gybe round it and drop, I cannot sail well past
it gybe drop and round once in the zone I must sail the
fastest course (one I would sail to get to finish
quickest)

Originally posted by gordon There is special exception for boats that are designed not to be able to sail straight downwind.

Gordon means NO special exemption of course. Typo I expect.
RS 400s and things sail dead downwind perfectly happily. They just don't do it particularly quickly.
I agree, the meaning of the rules in question is straightforward enough, but if you struggle hard enough you can find a hidden meaning in anything. If you're Dan Brown you can even make a lot of money out of it.

I can remember many years ago, being in a PC that was steadily misleading itself into a complete misinterpretation of a rule. Happily the offending party was much more sensible and retired before we could make complete idiots of ourselves!



Edited by JimC

That's right, and I was thinking quite wrong: it is 3 of her hull legnths as a circular zone around the mark you must not go outside, and once at the mark you must not sail longer into than you need to.

You could think of it as a truncated circle with the area beyond the gybe or lee mark being cut off due to 18.4 and the definition of "mark room"

Anyway, if you come in on starboard in lightish winds, on the LHS of the Leeward mark, I reckon you can sail a hot angle on STB , gybe to windward of the mark in the 3 boats zone and sail TO the mark on a new reaching angle (while probably taking your kite down)



I consider you have the luxury of doing this because 1. you have the port boats on 10  2. you have overlap on port boats on your beam and behind atleast
3. You then have "mark room" and can gybe by 18.4, taking no more room than required to sail that course
4. You are not sailing beyond your proper course before you are AT the mark  ie at the point you should harden up at a LM.

The crux of the interpretation is in "sail to the mark" ("mark room" definition) and "sail that course" 18.4

For an RS400 to "sail that course" in the abscence of other boats, it would be reasonable to sail hot angles and gybe near the mark to keep her speed: but here we lack " sail her proper course TO the mark" in the definition.

It is therefore vague and I interpret it differently to Gordon.

Whatdyyathink?

Originally posted by damp_freddie here is my escape plan Jim C: probably happens at many RS400 or 200 events.You come in towards the zone on a assy' gybe angle typical for light winds on STBYou pin out port boats at the zone and then continue on rule 10 with rule 18.1 also in hand, until you gybe BEFORE you are AT the mark or out the zone: you are allowed to gybe under 18.4 which resticts you to doing this in good time, not in angle of attach.The difference being now that 3 boat legnths is a bigger area to manoevre in than 2, giving you 1.5 boat lengths of radius each side of the mark, and a maximum cord of say 2 boat legnths.Thinking about it being so tight and r18.4 I don't see that you have to fall off before you gybe

I think you might have miss read your rule book, its not
3 boat length diameter its a 3 boat length radius from
the mark.... meaning a 6 boat length diameter.

here is my escape plan Jim C: probably happens at many RS400 or 200 events.

You come in towards the zone on a assy' gybe angle typical for light winds on STB

You pin out port boats at the zone and then continue on rule 10 with rule 18.1 also in hand, until you gybe BEFORE you are AT the mark or out the zone: you are allowed to gybe under 18.4 which resticts you to doing this in good time, not in angle of attach.

The difference being now that 3 boat legnths is a bigger area to manoevre in than 2, giving you 1.5 boat lengths of radius each side of the mark, and a maximum cord of say 2 boat legnths.

Thinking about it being so tight and r18.4 I don't see that you have to fall off before you gybe