Eriks Kalvins
Posts:29
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| 07/13/2006 12:42 AM |
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I'm finally at the point where I have to put deck hardware back onto 4136. Looking at Plan A, I see a range of spacing for the Jib and Genoa tracks. Is it generally thought better to be further inboard or outboard when installing them? Where do the new boats have them placed?
Thanks
Eriks |
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Rich Taylor
Posts:19
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| 07/13/2006 12:32 PM |
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I'm doing the same process with my boat (http://www.imageevent.com/taylorpix/j24work).
My approach to the genoa tracks was to put them as close to the inboard measurement as possible
since you can always pull the sail out with some sort of rigged barber hauler. The current Ragtime
has U-bolts (aka?) mounted on the curved cabin face for this purpose. Maybe you could go to the
stancion or stern rail base - but those might not be great angles.
For the jib tracks I haven't figured out any strategy - so I'll probably go for the middle of the
measurement range.
Q: What is a good way to correctly measure for jib track locations? The measurement guide doesn't
help much...
- Rich Taylor, #140 |
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Remco van den Berg
Posts:1
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| 08/24/2006 12:39 PM |
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I suggest to go for minimum distance.
Furthermore check the position relatively to the position of the mast and rigging!!
keep your symmetry in your deck lay out.
Remco van den Berg
Netherlands
NED 62 #5280 |
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steven clough
Posts:30
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| 08/25/2006 1:56 AM |
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Rich,
look at the following http://www.j24class.org/usa/pdfs/PLAN_A.pdf
This may help you in the proper measurements for the track.
Steve
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Rich Taylor
Posts:19
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| 08/25/2006 7:02 PM |
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Thanks... The proper measurement ranges are very clear in the class document plans.
Things that aren't clear (and not stated anywhere) are
(a) is the side-to-side measurement between the track middles, inner edges or outer edges?
Based on the way things are drawn I am assuming the middle of each track.
(b) What is a practical mechanism - without building any custom jig - for making sure that
the forward tracks are spaced the correct width and are really parallel? Things are easier for
the rear tracks where both are on a parallel plane with no major obstructions between
them. I have old style hatch rails that block anything like a direct measurement between
the two areas...
Also, for the rear tracks I took the strategy of aiming to minimize the horizontal spacing
with the knowledge that I could rig a barber hauler to pull the jib outward. Is there any
similar approach for the forward tracks?
I will just position them the best I can based on the measurements given in the class docs.
And someday when/if the boat is measured then I'll know that I did it right or I'll have a mess...
- Rich Taylor |
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Stuart Challoner
Posts:3
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| 08/28/2006 3:26 PM |
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| The current trend is to locate the aft tracks max outboard for heavy air and use a different set of genoa blocks with either large shackles or spectra cord to allow the block to trim inside for light air. Its rare that anyone is using a fixed position barber hauler, it does not provide enough adjustment for car location to set up for big air and waves or big air with flat water or maybe your current genoa trims slighlty different than your last. The trend for the forward track is to be max inboard. It will work the same but in reverse, the jib wants to pull outboard so you can adjust with the shackle length. My boat is not setup this way, but some of the good boats have made the modifcation and sail with multible genoa cars. |
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Nils Jannichsen
Posts:65
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| 11/17/2006 11:12 AM |
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As for now it looks like the ITC is going to ban this practise, when you attacht the blocks with cords the blocks get more damaged and are damaged sooner, and this practise makes the sailing on a J24 unneccasery more complex.
regards
Nils Jannichsen |
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jon powell
Posts:3
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| 11/30/2006 2:49 PM |
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| nils i am about to move my tracks out i hadnt heard about banning using extended shackles or ropes, where can i find out about this. |
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Chris McLaughlin
Posts:3
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| 02/11/2007 4:05 PM |
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Outboard is best for aft tracks. Inboard for Jib tracks.
The rules have changed and the bearing surface of the aft track block will have to be no higher than 110mm from the deck, measured when the block is held in an upright position.
Its a shame, because the technique has been used since Ken Read's days. Personally, I believe it would have been better for the class to release the information to all competitors, via the web site rather than introduce the ban. But it was a collective decision.
There is an argument that long strops can make genoa tracking more difficult and penalise the less practised. They also spelt the end for those using the Lopez block technique.
We will mourn their passing on Hedgehog... |
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Eriks Kalvins
Posts:29
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| 02/12/2007 11:56 PM |
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How would this affect the use of Lopez blocks?
The height of the bearing surface of the block from the deck isn't any higher from the deck than a standard turning block... its just the track slide, shackle and block. |
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Chris McLaughlin
Posts:3
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| 02/13/2007 3:00 AM |
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Thats my point. The new rule requires 110mm vertically up from the deck to the bearing surface of the block. If the Lopez system on its installed track and jib cars makes the bearing surface higher than 110mm then it is illegal.
If it does not then happily I am wrong. Perhaps to help, someone would measure it. I don't use Lopez so can't be of assistance.
Chris |
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Eriks Kalvins
Posts:29
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| 02/14/2007 7:00 PM |
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Just measured my Lopez blocks. If I'm understanding the measurement correctly, with the bearing surface being the highest point over which a line would run on the block, so in this case the middle of the 'V' shaped channel of a 57mm Harken Ratchamatic, then that gives me a distance of 80mm from there to the bottom of the track slide... so probably about another 2 or 3mm for clearance above the deck, still leaving quite a bit of vertical distance.
I seem to remember seeing larger blocks used in non-Lopez setups, and would be interested to know how close those come to the limit.
As well, is there really any perceivable advantage that someone using a larger block in a non-Lopez setup would have over the smaller Lopez block, which would be equalized by putting in a longer shackle between the track slide and the block? (3cm difference in my case, minus that which you lose by the angle of the standup)
Eriks |
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Lorne Chapman
Posts:149
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| 02/20/2007 9:59 PM |
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Unfortunately this topic has two subjects. On the most recent - the attachment of the genoa turning blocks to the cars let me make a few comments.
What has been issued is a rule interpretation by the ITC. Rule 7.2 does not allow for the blocks to be attached to the cars in any other way than "directly", and following rule 1.3 there is no permission for using extended strops of fabric or other material. All that is being done is stating how the current rule is being interpreted by the ITC for measurement purposes on an aspect that has not received focus previously, bearing in mind rule 1.3 that basically says that if the rules don't say you can, you can't. There are mechanisms for changing the rules - open to all - so there is an avenue open to those who wish to propose a change.
The 110 mm limit was set after measuring a number of car and block combinations, including Lopez blocks. All that we could find came in at or under that limit. The Lopez blocks measured in the sample were lower than some of the others.
There is no initiative or intention to ban the use of "Lopez" blocks as they do not appear to violate any class rules.
The ITC has been asked to consider attachment of the block to the car using spectra or similar rather than a shackle. We are amending the rule interpretation to allow this, as long as it is an attachment that can not be altered in length while sailing. See the rule interpretation for the revised wording.
Lorne Chapman
Chair, International Technical Committee |
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Ed Putnam
Posts:3
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| 05/08/2007 7:37 PM |
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Back to Eric's question regarding track position, I'm in the process of repairing the deck under the genoa tracks on my boat "1977 Hull 57", which has the orginal 4' long track, in its orginal position. My plan was to cut the track down and move it max outboard and forward per class rules.
The problem/question that I'm running into is that a 2' (610mm) long track and placing it about 3.25" aft of the cabintop bulkhead (just enough spacing to place a car on the track), you exceed the max aft position of the track (1750mm or 68.8976") I called it 69" to be safe. I didn't find a minimum length for the track in the rules. Can you cut down the track to 22" to 23" long? And is this something you want to do? As I don't believe you need the last bit of track for the correct (fast) sheeting angle.
Just want to make sure any changes are legal and fast.
- Ed |
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