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Proper car location in track for Jib

14K views 12 replies 12 participants last post by  heyross 
#1 ·
Hello,
The wife and I are working out the kinks on a new boat for us (and fairly new to sailing to boot). We have a Newport 33 and the other night on the water noticed that when close hauled we had a lot of fluttering of the leech on the jib (telltales seemed to be streaming just fine). I am assuming that we may have the cars in the wrong location on the tracks for the jib sheets and any help on determining what the proper location would be, or if the problem is likely something else any suggestions would be appreciated. Thanks
 
#4 ·
Try to see how relatively 'round' or curved the foot is between tack and clew compared to the leech. If the foot seem's stretched flat and the leech is fluttering then it may only be lead car setting that's the issue.

As a starting point, drawing an imaginary line from the block through the clew it should intersect the luff at it's midpoint between tack and head.
 
#5 ·
The jib car position controls the amount of twist in the sail. When the wind picks up the jib stretches and the top twists open. If the top is too open the jib may flutter and you won't be able to point well. To close the top of jib you need to pull the clew down (towards the center of the earth). To pull the clew down move the car forward. When the wind eases the jib stretches less and the top of the jib will be closed too much. To open the top of jib you need to pull the clew down less, therefore, move the jib car aft. If the top is too closed you will be slow.

If the leech is stretched as Nolatom suggested, you may be able to to reduce the fluttering by tightened a leech control line.
 
#9 ·
If the leech is stretched as Nolatom suggested, you may be able to to reduce the fluttering by tightened a leech control line.
+1 to Hudsonian. The leech doesn't even need to be stretched to flutter. Fact of sail trim. Be sure to ease the leech line again in light air to avoid cupping the leech (think parachute).
 
#6 ·
Just imagine yourself holding the clew in your hand and trying to pull it one direction or the other to make the foot tighter or the leech tighter. Fluttery means loose, so you'd pull down more if the leech is fluttering, back more if the foot is fluttering.

Now position the jib car so that the sheet is pulling in exactly the direction you determine. Moving the car forward pulls down on the clew, moving aft bulls back on the clew.
 
#7 ·
The best advice given to me for finding initial car position is:
1. Fold the sail in half along the leech
2. Put a small felt mark there
3. Use a straight edge (tight piece of cord etc) from the felt mark through the centre of the leech to the clew where the jib sheets attach to the jib. On all my jibs I have drawn about a 2 ft felt line through the clew.
4. Adjust your jib car so your jib sheet forms a straight line with the felt line on the sail. This will result in evenly pulling on both the foot of the jib and the leech of the jib. Remember both the leech and the foot are curved!
5. If the wind is not strong enough, you want to close the leech and capture the wind in the jib. Moving the car forward pulls down on the leech, shortening the curve and closing the jib up. This also releases pressure on the foot making the foot more curved (giving the jib more belly) and thus powering the sail up
OR
If the wind is too strong, you want to open the leech to get rid of the wind. Moving the jib car aft puts less pressure on the leech making it more curved, opening it up and allowing excess wind to escape. Also the sheet now pulls more on the foot of the jib flattening the foot curve and and the sail overall.
6. Each of these changes alters the pressure along the leech and the foot. The pressure may be altered sufficiently to cause either the leech or the foot to flutter. This fluttering has little effect on boat speed, its just very annoying. After each alteration of jib car position I alter the leech and luff cord accordingly to take the flap out of the sail. My leech and luff cord are attached to Velcro ends allowing for easy adjustment.

Hope this helps
Regards
Ross
 
#12 ·
To set your jib lead position correctly, sailing closehauled, head up:
- if the upper windward telltale lifts first, move the block forward,
- if the lower windward telltale lifts first, move the block aft.

In light air you may want to adjust the proper position a little forward for fullness, in heavy air, a little back to flatten the bottom of the sail.

If your leech is fluttering with the correct jib position in use, correct it with the leech line, if you cant then the jib needs to be worked over by a sailmaker.
 
#13 ·
Dear all,
I stand corrected. Part 6 should read leech cord and FOOT cord. SVAuspicious raises a good point in that too often, especially in a heavy race, we all want to pack up quickly often resulting in things like the leech chord setup for heavy weather sailing and it may now only be blowing 15 knots. Every time you pull your sails up, let all the fine tuning devices off and start all over again.
 
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