SailNet Community

SailNet Community (http://www.sailnet.com/forums/)
-   Seamanship & Navigation (http://www.sailnet.com/forums/seamanship-navigation/)
-   -   Proper car location in track for Jib (http://www.sailnet.com/forums/seamanship-navigation/74420-proper-car-location-track-jib.html)

TSAKUS 05-13-2011 03:42 PM

Proper car location in track for Jib
 
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

Boasun 05-13-2011 04:18 PM

may want to move your fair lead block forward a tad bit. Experiment with moving it for a reduction in the flutter and where the sail will draw well.

nolatom 05-13-2011 04:30 PM

If moving the car fore or aft doesn't affect the leech flutter, then likely the leech is blown out or stretched. then you'd need to see your sailmaker for a fix, if indeed the remainder of the sail is still in stable 'shape'.

Faster 05-13-2011 05:09 PM

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.

Hudsonian 05-13-2011 05:24 PM

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.

AdamLein 05-13-2011 06:45 PM

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.

heyross 06-01-2011 07:52 AM

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

puddinlegs 06-01-2011 08:04 AM

Quote:

Originally Posted by heyross (Post 736202)
The best advice given to me for finding initial car position is:
1. Fold the sail in half along the leach


Luff I'm guessing...no?

SVAuspicious 06-01-2011 11:19 AM

Quote:

Originally Posted by Hudsonian (Post 730135)
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).

Flybyknight 06-13-2011 08:27 PM

Leech?
 
Quote:

Originally Posted by puddinlegs (Post 736207)
Luff I'm guessing...no?

Yes, I was thinking the same thing.

Dick


All times are GMT -4. The time now is 03:14 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012