Hi all

Any thoughts on what is causing the creases in the main

Regards Don

Not really overbend creases, more like the lower roach is collapsing. Hang on, I have to go back to the pic.

Yeah, definitely some batten poke, mainly on the top short batten, a bit less on the next one down. Main has probably got a bit deep in the back over time . Some good full battens would get in looking a glamour probably.

Main luff curve not matched to mast bend.
Beginner error
Looks like mainsail made for a different boat with a stiffer mast maybe carbon section
Need to increaser the luff round

At first glance it looks like the luff round is in correct. The second set of creases half way up though look like the panels were glued down with mismatched edge tension.

Looks stretched to me. Where the battens are it looks fine.

A main with a square top like that should have full length battens to support the body of the sail when there's leech tension.

As best i can see from the pic, it doesn't....

(as i just saw jethrow said)

More halyard tension or cunningham may help...

or or maybe the rig tension is out and needs a tune up...

Or the material may be stretching or stretched along one axis only with the material bias..

I know that look, in my case I can peak up the gaff a bit to get rid of the creases but then I end up with a nasty cupped leach. I've been running a line Cunningham fashion from the 1st reef point to the tack, all the crease gets gathered in the tack area. A recut would help and full length battens but ! $&@$&?

i know that look to my sails always look like that

2 reasons:

old sail that that is stretched. Needs to be fully battened as someone has already pointed out.

They are overbend creases to make sure your sailing with no backstay in those conditions and retune your mast to fit the luff curve of the sail

I am with Ramona on this, not luff round as the creases also lead near the hounds. Looks like a sail with unequal loading of the radial panels. Take the pics to the sailmaker at Kettering and get him to unpick and resew it. Cheers

looks really crap dosnt it ! .....too much out haul for the like air ?

Before doing any of the above remove the clew and release the roach line if fitted,
host main with halyard tension and down haul Cunningham adjustments and take some more pictures preferably on mooring or Marina berth with low winds.
its possible the roach line is too tight and the clew/boom is hanging from roach.

So many opinions about one sail! OK, here is one more:

There appears to be no backstay tension which is fine as in both shots it is clearly light air and the boat is headed downwind.

The wrinkles in the main are not doing much damage as the flow over the sail is minimal on this point of sailing.

But upwind, it will be a different matter. However, I expect that some backstay tension applied upwind will create enough mast bend to draw the wrinkles out as the luff is drawn forwards.

Some Cunningham Eye tension may also be required but that should also be slack for sailing downwind.

Like Jethrow, Ramona and Kankama (and they include the only trained sailmaker amongst us, I think) I don't believe it's overbend wrinkles. They radiate more consistently from the clew. Ian Short describes overbend creases as "quite pronounced creases running diagonally from the luff to the leech". These creases aren't continuous like overbend wrinkles tend to be - above the bottom batten, for example, the wrinkles start from an unwrinkled patch of cloth.

Also the mast has little bend in it in the pics and one can't imagine any sailmaker designing a sportsboat sail with almost no luff curve. IMHO it's just an ageing sail with batten poke. Note the jib has similar issues at the low batten.

Ok, thought you all might like to know what the issue was and how we resolved it.
I had a little inside info as i kknew the boat and knew that the older main that now had the creases like the one in the pics, did used to set fine so I didn't think it was sail related.
Upon seeing the pics I thought it was the sail being over tensioned between the hounds and flew, OR being under tensioned between the leech and tack/lower luff.
The boat has an adjustable forestay so what we found was that the owner wasn't pulling enough on the forestay and when we pulled enough to get good rig tension it took some of the prebend out up high.
Basically the adjustable forestay is for loosening off at the dock, or going from tight to bloody tight!
We then loosened the lowers a bit as the bottom section was very straight, this helped the mast have a nice smooth prebend once the forestay was pulled on tight.

Owner sailed a twilight tonight with the old main as it was blowing but said it set better than it ever has!

By the way I'm a rigger down this way, so if you need anything done you know where to find me ;)

Hi all

Here is the old main during tonight's race after Rumblefish had a play with it today









And this is the boat that beat it in tonight's race

Although be fair to Mick we started 15 mins ahead of him and finished 12 minutes in front of him so he managed to make 3 minutes on us tonight in his 73 minutes of sailing

More main halyard tension and a tighter vang needed Donk!!
I was looking at that boat this arvo and the vang looks very under purchased.
On the Elan we have double that purchase then going to clear either side of the cabin, would be a good upgrade for that boat.
With the square top and a fwd mainsheet position (and no trav) you need lots of vang to get leech tension

Thanks for the pics though:)

Hi Rumblefish

Thanks for the hints

It was blowing 20 knots at the start and we had a the main halyard tight but it dropped down to 15 knots after the first lap and the around 10 knots at the end

During the race we eased the main halyard as the wind dropped off but let it go a bit to far and Jeff suggested at one point that we tension it a bit more but at the time we had the head sail sheet on the winch behind the halyard clutch and were going to do it after we tacked but we forgot to do it

Mick is really happy with the changes you made to the Elliott today

Regards Don