Creases in the mainsail - any suggestions?

[AndyL]

Our 2004 Hunter 36 came with a newish mainsail so I know it's not worn out. It's a traditional full battened sail. We have creases that run from the batten cars towards the clew. They extend about halfway to the clew and are worst at the bottom of the sail. We recently had our standing rigging replaced and the rigger says the mast is set to the correct bend as per Hunter's spec. From doing some reading it sounds like the sail's cut doesn't match the mast bend. I can't remember whether we had these creases with the old rig and/or if they were less prominent.

Has anyone experienced this? Could I be doing something wrong with halyard tension or some other control?

Thanks,
Andy

 

[danstanford]

Do they persist when you are sailing? Sounds like the boom angle is too low for some reason but if so you should see them lessen if you hold up on the boom, or get the sail full of wind which will raise the boom anyway if you don't have the main sheet (or vang) on tight.

 

[dlochner]

Photos showing the creases would be really helpful.

 

[AndyL]

I'll try to get pictures but not sure when our next sail will be. Here is a diagram that shows what I was describing:

Yesterday we were out in virtually no wind and the creases were really noticeable - I think they are less obvious in decent wind but still there.

Regarding boom angle - after the standing rigging was replaced I noticed that the boom was a bit higher at the end. With the old rigging, releasing the topping lift and letting the boom sit on the vang would leave it close to the top of the arch. Now it is probably 6" above the arch. I assume that means the mast rake has changed since the vang appears to be mounted in the same place (the vang has no gas strut so it can't be that). Not sure if that is related to these creases because I don't remember what they were like before the rigging was replaced

 

[jssailem]

Creases happen in sails based on how they are stored.
Things to check

1. Is the sail to the top of the mast.
2. Is there adequate tension on the mainsheet halyard.
3. A Cunningham can be used to draw the Luff down. Snug the luff but avoid putting in vertical wrinkles along the luff.
4. Check that the boom is level.

If you want to change out the folds, when the sail is lowered, stand at the mast and reset the way the sail folds on the boom or in the LazyJacks/Sail Pack/Dutchman system.

 

[danstanford]

I'll try to get pictures but not sure when our next sail will be. Here is a diagram that shows what I was describing:

View attachment 217741

Yesterday we were out in virtually no wind and the creases were really noticeable - I think they are less obvious in decent wind but still there.

Regarding boom angle - after the standing rigging was replaced I noticed that the boom was a bit higher at the end. With the old rigging, releasing the topping lift and letting the boom sit on the vang would leave it close to the top of the arch. Now it is probably 6" above the arch. I assume that means the mast rake has changed since the vang appears to be mounted in the same place (the vang has no gas strut so it can't be that). Not sure if that is related to these creases because I don't remember what they were like before the rigging was replaced

The weight of the boom will close the leech and try to stretch the sail as it sags. I would try raising the boom by hand with the sail full of wind and see it they go away. We see similar creases when the wind is light and a bit of Cunningham will help make it look better but I don't think it helps in the light where you want draft a bit further back.

 

[Davidasailor26]

Those creases sure do look like over-bend to me. Pull the main halyard tight to the gooseneck and estimate how much pre-bend there is between the straight halyard and the back of the mast as the most bent spot. You can use the width of the mast to judge the distance. My second guess would be a shrunken bolt rope preventing you from getting the cloth in the luff taut.