drLaser
Member
In a private letter to drLaser, an interesting question was raised. The letter is reproduced below with the consent of the author:
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From: Finn Hassing
Date: Thu, 18 Mar 2004 19:46:05 -0500
Dr Laser:
I have studied the clew tie-down design consisting of stopper balls spaced with plastic tubing. While this seems like a good way to reduce friction, the legality of the design is questionable in my mind - as the rule book states "simple balls or tubing", which strictly interpreted, would not allow "balls and tubing."
Can my mind be put at ease before I invest time and money in implementing this design.
Finn Hassing
177009
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The clew tie-down rig Hassing refers to is the one described in the (ILCA members-only) article titled "drLaser's Clew Tie-down" published in the "Maintenance & Fitness" and "Class & Racing Rules" sections of the drLaser web site.
The related ILCA Rule is:
3(g)ii. The clew tie down may be passed through simple balls OR
tube/tubes to reduce friction.
Clearly, the linguistic question is whether the OR is an INCLUSIVE or
EXCLUSIVE "or" (as posed in mathematics).
Using set theory notation, does "A or B" mean
A U B (the "inclusive" case)
or does it mean
(A U B) - A ^ B (the "exclusive" case) ??
Or in plain English, if a rule allows "A or B", there are two possible ways of interpreting this:
1. Things that are A and things that are B are allowed, as well as things that are both A and B; or
2. Things that are A and things that are B are allowed, but things that are both A and B are not allowed.
What does "or" mean to ILCA's World Council?
In the case of Rule 3(g)ii, the "drLaser opinion" must be obvious, since such a tie-down rig is published as a legal rig in the drLaser web site since 18 May 2002. But a general discussion is important for correctly (and consistently) interpreting ALL such ILCA rules where the word "or" is used. And there are many!
Shevy Gunter
Member, ILCA-NA
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From: Finn Hassing
Date: Thu, 18 Mar 2004 19:46:05 -0500
Dr Laser:
I have studied the clew tie-down design consisting of stopper balls spaced with plastic tubing. While this seems like a good way to reduce friction, the legality of the design is questionable in my mind - as the rule book states "simple balls or tubing", which strictly interpreted, would not allow "balls and tubing."
Can my mind be put at ease before I invest time and money in implementing this design.
Finn Hassing
177009
-----------------------------------
The clew tie-down rig Hassing refers to is the one described in the (ILCA members-only) article titled "drLaser's Clew Tie-down" published in the "Maintenance & Fitness" and "Class & Racing Rules" sections of the drLaser web site.
The related ILCA Rule is:
3(g)ii. The clew tie down may be passed through simple balls OR
tube/tubes to reduce friction.
Clearly, the linguistic question is whether the OR is an INCLUSIVE or
EXCLUSIVE "or" (as posed in mathematics).
Using set theory notation, does "A or B" mean
A U B (the "inclusive" case)
or does it mean
(A U B) - A ^ B (the "exclusive" case) ??
Or in plain English, if a rule allows "A or B", there are two possible ways of interpreting this:
1. Things that are A and things that are B are allowed, as well as things that are both A and B; or
2. Things that are A and things that are B are allowed, but things that are both A and B are not allowed.
What does "or" mean to ILCA's World Council?
In the case of Rule 3(g)ii, the "drLaser opinion" must be obvious, since such a tie-down rig is published as a legal rig in the drLaser web site since 18 May 2002. But a general discussion is important for correctly (and consistently) interpreting ALL such ILCA rules where the word "or" is used. And there are many!
Shevy Gunter
Member, ILCA-NA