Flapping sail near top of mast on a beam reach

[simonpickard]

Hello all,

As the topic says really.
I've noticed that when on a good beam reach there's a flap happening near the top of the mast. Can't remember it being there when I first got the boat. I have a fully batterened main and it looks to be where the top car (about 1.5m below the very top of the sail) joins the mast.

It's like some weird vibration starts happening when I hit a certain angle with it.

Any ideas how to stop this?

Regards,
Simon



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[Delancey]

Needs leach cord would be my first guess. Otherwise, the top of the sail is falling off too much, you're luffing and need to trim.

[Suijin]

Kinda hard to speculate as your description is rather vague. You say it's where the batten meets the mast, which makes it sound like it's along the luff. That would be a halyard tension issue unless you have some sort of fault at the car for the batten or other slide. If it's along the leech then as Delancy mentioned tightened the leech line, although if that were the cause I would not expect it to be so localized. Or maybe you just need to put some vang on.

A picture would be worth a thousand words.

[chris95040]

Excessive twist? Maybe tighten up your mainsheet (but ease out the traveler to keep the same angle of attack on the rest of the sail.)

[JPA Cate]

The previous writers have it pretty well covered, but I had another idea to add: you might try tightening the top batten, itself. If you have the adjustable cars, we had one fail one time, that made it too loose. So your adjusting mechanism may have bit the dust, or worked loose.

Ann

[Seasick Steve]

I agree with Chris.

First check the halyard tension - no horizontal creases in the luff or crow's feet at the slides.
Then set up the angle of attack with the traveller if you're close enough to the wind.
Then pull the boom down with the sheet to reduce the twist.

If further off the wind the traveller is less useful (it needs to be down to leeward) and you control the angle of attack with the sheet; crank on the kicker to reduce twist.

Not the leech line though - that just controls the extreme edge of the sail.

Or maybe the sail's horribly stretched :-(

(Hope I'm not talking out of my sternport)

[Snore]

What do the tell tales say???


Like many I am on the learning curve. Since adding tell tales, the boat is quicker. Obviously, it is not the boat but a case of better trimming.


YMMV

[Seasick Steve]

The telltales on the main should be on the leech, not on the luff as with the jib. They'll tell you if the airflow is leaving the sail smoothly, which it shoud be of course. If the whole head of the sail is flapping that's a better signal than any telltale!

I've just re-read the OP a bit more carefully. Is it JUST the luff that's flapping/vibrating? If so, changing the halyard tension should sort it out....but it does it every time you hoist it??

[markpierce]

If you don't have one, a boomvang would help.

[simonpickard]

Great advice as always, I think it might actually be the car as someone mentioned. I didn't have the issue before and now I do so something's worked it's way loose. Either that or I'm getting worse at sailing which is entirely possible.

I'll try all these out though next time I'm out there.

Thanks again,
Simon