Differential control of jib and main
Posted: 02 May 2004, 17:57
With an arm winch (or with a spectacular sort of drum on a drum winch) it is possible to intentionally make the jib behave differently from the main: sheet out at a somewhat faster or slower rate at close-hauled, for instance. Is this acceptable practice? I don't see what prohibits this, though there is nothing that permits it either (or permits perfectly simultaneous jib and main action, for that matter).
I notice that the 2003 Rules omit the requirement that was at C.7.7(a)(1) saying that sheets "shall be worked simultaneously and without any means of independent and/or automatic trim." (I speculate that perhaps this was done because no existing boat really had a perfect relationship of jib and main that did not involve differential in their movement, simply because the relationships of boom angle, and locations of hull-mounted sheet post or eye and the attachment point on the boom always vary from jib to main, and cannot be perfected; but that's not my main point.)
A couple of the questions posed for interpretations, issued as 3 and 4.15, dance around this issue, wiithout broaching it outright.
If you want to visualize the technical issues, I encourage you to look at the following articles by Lester Gilbert:
http://www.onemetre.net/Download/Sheeting/Sheeting.htm
http://www.onemetre.net/Download/Armwinch/armwinch.htm
However, it's possible to do the same thing using a crooked, two-ended winch arm, where the jib end is not opposed directly to the main end, but angled somewhat from the continuation of its axis.
Comments?
I notice that the 2003 Rules omit the requirement that was at C.7.7(a)(1) saying that sheets "shall be worked simultaneously and without any means of independent and/or automatic trim." (I speculate that perhaps this was done because no existing boat really had a perfect relationship of jib and main that did not involve differential in their movement, simply because the relationships of boom angle, and locations of hull-mounted sheet post or eye and the attachment point on the boom always vary from jib to main, and cannot be perfected; but that's not my main point.)
A couple of the questions posed for interpretations, issued as 3 and 4.15, dance around this issue, wiithout broaching it outright.
If you want to visualize the technical issues, I encourage you to look at the following articles by Lester Gilbert:
http://www.onemetre.net/Download/Sheeting/Sheeting.htm
http://www.onemetre.net/Download/Armwinch/armwinch.htm
However, it's possible to do the same thing using a crooked, two-ended winch arm, where the jib end is not opposed directly to the main end, but angled somewhat from the continuation of its axis.
Comments?