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Forums IJCA Forums
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IJCA Forums
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Lorne Chapman
Posts:158
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| 09/11/2007 6:38 PM |
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Rule Subject: Forestay length
Description: The intent of the current rules is to ensure the sail plan placement on all boats is equalized. To be equalized, sail plan placement must be equalized relative to the location of the keel. Because the measurement point for the keel (stern) and the sailplan (bow) are different the intent of the rule is not realized.
Current Rule: 3.5.3(c) “With the forestay in place, the distance measured in a straight line form the fixing point on the mast bracket to the intersection of the stemline and the sheerline shall not be more than 8670mm or less than 8595mm.
Proposed Rule: 3.5.3(c) Rule can be just omitted completely or could be change to read “The forestay may be fitted with and adjustable turnbuckle”.
Reasons:
a) It is known today that the overall lengths of J24’s in existence vary as much as 55mm. This difference, combined with today’s rules effectively moves the sail plan foreword on longer boats and backwards on shorter boats.
b) It is an overwhelmingly accepted belief based on 25+ years of racing that longer forestays and longer J’s are one key to performance success. This would mean that longer boats are penalized with respects to this performance dynamic.
c) The #1 principle held by participants of One Design sailors is that all participants regardless boat ownership are afforded equal opportunity to prepare their boat the same as others. This is not the case today with respect to this rule.
ITC Position: Currently under discussion.
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stephen estes
Posts:11
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| 10/20/2007 7:35 PM |
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I had to think the logic through, but this is true.
If longer in the stern, pulls keel back.
If longer in bow, pulls mast forward.
Or, some combination of the two.
How widespread of a problem is this?
What is the statistical distribution of variance in boat length?
Are most boats pretty close to the same length, with just a few aberrations?
Or, out of all boats, is there a more general distribution of lengths, within the 55 mm (~ 2 3/16") difference in boat lengths?
(55 mm seems like a lot.)
I don't see any problem with removing the forestay limits.
It seems like the real result is to remove a somewhat artificial limitation on experimentation.
Without the limit, teams are able to experiment, and find the setup they feel works best for them.
Can it be changed during a regatta, like moving the mast butt, or changing rig tension?
That would seem to complicate sailing, which seems a little counter to the intent of the Class Rules.
I can just picture trying to tighten the headstay in between races, in rough seas, because the wind came up, and I want less weather helm.
Sounds exciting!
I have personally been burned under the existing rule, when I purchased a new headstay that initially measured 2mm short of max length, and later was too long.
(I think there is some initial stretch, or elongation that takes place on a new headstay.)
Just offering some thoughts -- no strong opinion one way or the other. |
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Nils Jannichsen
Posts:65
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| 11/14/2007 5:18 PM |
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I think this is a speed related item, and also a cost related item, and about complexity to sail a J24.Oone of the complex things on sailing a Flying Dutchman is to determine how much rake you use, a part of an inch makes a big difference in speed and height. I think on the J24 adding 7 cm off extra forestay lenght would create different sailing
Sail makers would come with an extra feature in their tuning guides and will come with more different shapes sails for light crews using more rake and heavy weather sails also to be used with a different amount of rake then the light weather version, top crews will probably show up with more sets of sails and decide on the latest moment which set to use.
When omitting this rule we will make measuring a little bit less difficult but we would add a lot of opportunities for boat makers and sail makers to add more complexity, which is not good for the class, I think
It is unfortunately that we have to live with minor differences between different builders, we must work hard that differences between boats are not getting bigger
Nils
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Paul Beaudin
Posts:8
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| 02/07/2008 7:42 AM |
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| It is a great idea it should have been done years ago. If we removed the forestay length we would go to a full height mast and it could involve new rigging for some. It could help equalize the stock boats from those that were shaved in the ends. |
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