I was sailing on another person's boat. After raising the loosefooted main in sub 10 knot wind, and after making all the "normal" sail trim adjustments, there was a persistent diagonal wrinkle stretching from the clew to a point on the mast about one third of the way up from the tack. When the breeze picked up to 10-15 apparent, it didn't go away. Sails dated to 2008 but appeared quite fresh and well maintained. Any ideas?
Diagonal crease in mainsail
- Thread starter haddad126
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Without a picture hard to say, but they may be infact, an intended part of the sail design. They are sometimes called "speed wrinkles" See Tip #5 at:
http://www.sailingworld.com/experts/little-things-that-make-a-big-difference
http://www.sailingworld.com/experts/little-things-that-make-a-big-difference
Another possibility is that the luff bolt rope is shrinking. Easy fix for any sail loft or someone with enough sewing skills to open the luff seam and re-set the bolt rope. I had SailCare do mine when I sent the sail in for cleaning. This worked wonders for the shape of my main a few years ago.
Creases or 'girts' that develop in a sail are the result of the concentration of tension on the head, tack and clew.
On a cross cut sail - one with all the panels running along the horizontal plane - with a perfectly raised/tensioned and 'shaped' sail if such 'girts' develop from the clew and run to about 50% of mast height ... thats OK !!!! What is happening is the 'material' is simply becoming stretched on its 'bias'. The 'better' (costly) the sail material the better the 'bias stability and less creases/girts formed in the fabric.
In woven fabric there are vertical threads and horizontal threads ... such girts develop because the sum of the resultant forces are at 45° from the up and horizontal threads - on a 'diagonal' or bias.
Usually most/many sailors simply raise a dacron sail to 'just up' ... and the result is the aft end of the boom will sag toward the cockpit ... and which sometimes causes the 'girts' that form along the 'diagonal' to lower than 'halfway' up the mast. Also can happen if the outhaul is 'too tight' and for the exact same reason.
Suggest that your friend first correctly RAISE the dacron sail: so that the sail takes its 'as designed' shape ... then make the proper outhaul adjustment (controlling the 'amount' of draft) http://forums.sbo.sailboatowners.com/showthread.php?t=120970 - post #1
;-)
On a cross cut sail - one with all the panels running along the horizontal plane - with a perfectly raised/tensioned and 'shaped' sail if such 'girts' develop from the clew and run to about 50% of mast height ... thats OK !!!! What is happening is the 'material' is simply becoming stretched on its 'bias'. The 'better' (costly) the sail material the better the 'bias stability and less creases/girts formed in the fabric.
In woven fabric there are vertical threads and horizontal threads ... such girts develop because the sum of the resultant forces are at 45° from the up and horizontal threads - on a 'diagonal' or bias.
Usually most/many sailors simply raise a dacron sail to 'just up' ... and the result is the aft end of the boom will sag toward the cockpit ... and which sometimes causes the 'girts' that form along the 'diagonal' to lower than 'halfway' up the mast. Also can happen if the outhaul is 'too tight' and for the exact same reason.
Suggest that your friend first correctly RAISE the dacron sail: so that the sail takes its 'as designed' shape ... then make the proper outhaul adjustment (controlling the 'amount' of draft) http://forums.sbo.sailboatowners.com/showthread.php?t=120970 - post #1
;-)
I agree with more halyard tension. I have the same problem with mine. Its an older sail and I get the same diagonal wrinkle if I don't put enough tension on the halyard. It took me a while to figure this out. I learned to make sure the main sheet and the boom vang had to be loose in order to get the halyard tight.
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