i get a slight creasing along the middle of my sail when i am windsurfing.

the sails look fine when i rig them, the creases appear only when i have wind in my sail.

does anyone know if this a rigging issue, i have tried fine tuning it, but to no avail, and since it happens on several sails i have tried, i am thinking its something to do with the mast?

any advice is appreciated, cheers,
Brock

Can you elaborate on "Along the middle"?

Diagonal ones in the upper panels are normal. I think the technical term is 'breaking'.

Like Gestalt's sail in this picture?

i remember that day it was bloody windy, i think everyone's sails had creases like that

I had same as Gestalts when not sailing, but only in panels around the boom and perpendicular angle to those. Not the little creases around the battens, actually in the panels. They would disappear when I let downhaul off completely. Looked like needed more outhaul to remove, but sail was then flat. Sail is a camless freeride sail.

I've noticed the same creases in ad for Fanatic on a North sail, so possibly a common tuning issue?

I have only just recently added a little more batten tension, like a 3/4 twist to bottom 3, and creases have gone. Sail is also performing better, (even) more power and stability.

as a reply to swoosh's diagram, well drawn by the way, yes the creasing is in a diagonal direction, but i have noticed them mainly in the main panel at boom level. there is mainly one large crease.

could it have something to do with the stiffness of the mast?

another factor, i tend to use a larger sail than most under the same conditions.

i usually get the creasing on my 5.7

most people are out with 5.0 or 5.2 when i use that sail, so maybe the mast is bending/flexing too much?

It depends on the design of the sail- from sailing with Gestalt I know he tends to go a little bit underdownhauled but it still would not change the breakup of that KA much. Look at the 3rd batten up in the sail it has a fair bit of pre-shape in that it is still hooking around... great for bottom end and gusty conditions (and also probably why someone as tall as me has his boom set so low). All that shape is in the sail, as the top 2/3rds of the sail wants to twist open it has to fight that shaping thus the creases form. To help avoid this you need flatter panel sections in the head and more in built twist ie more like a race sail. Here is 1.7m bigger sail in same wind with no creases at all-

If I hit a big bit of chop the sail twists off more rather than folds, the downside is reduced bottom end and a much less forgiving feel to a more freeride sail.

ka43 said...

Oh to have flat water and wind like that, jealous

Its a novelty for us too bar about twice a year.

There is some blurb on the KA site about creases that appear when sailing, but I'm buggered if I can find it now. Talks about how they'll never put form above function again.

jeez, i was a lightweight last year in that photo..... 12 months forward and another child and the toes aren't so obvious when i look down.

KA design their sails to break like in the image. i also think the non cambered sails do it more than the cambered.

the photo was a 40knot day. i was on a 4.7 kaos and a 70lt wave board. the sail was originally rigged for pete who i borrowed the setup from. so some tweaking was needed to get the settings right. (mainly boom). my boom is too low in that image. arms too bent. should have raised it another 2 inches. i do remember lowering it that day to gain more control and then raising it a bit after lowering it to far.

creases running in other directions or in the sail while lying on the beach to me mean wrong mast or incorrect rigging.

panda - some of the KA sails 5+ years back had small creases in them when rigged. that was the result of the sail shaping and didn't adversely affect the performance. hence the function over form thing.

mk - underdownhaul..... we used a winch on the sail in the photo.

edit** yesterday i bought the sail in the photo....

NotWal said...

Gestalt said...

jeez, i was a lightweight last year in that photo..... 12 months forward and another child and the toes aren't so obvious when i look down.

You been having babies again Gesty? You should get Sarah to do it. That's what girls are for.

the deal is, once the child is born all weight from the mother is then transferred to the father. now that's sharing.

mkseven said...

Where do you find all these 40knot days and can you please share them with the rest of us

Think about what MarkAus said about you're turban. Unless you've set a new qld speed record that is.

here ya go mate.

www.bom.gov.au/climate/dwo/200712/html/IDCJDW4050.200712.shtml

just look towards the end of dec [}:)]


edit** here are a couple more

http://www.bom.gov.au/climate/dwo/200802/html/IDCJDW4050.200802.shtml
www.bom.gov.au/climate/dwo/200803/html/IDCJDW4050.200803.shtml
www.bom.gov.au/climate/dwo/200811/html/IDCJDW4050.200811.shtml

if we set the limit at 30-35 then every month is a winner.

so glad i got that 4.7

mkseven said...

Your 4.7 is wasted money mate, having owned 4.5's etc every single time i've used the twice and that has been it... no more, no point.

sorry brock i will delete that post one of the youngins at the beech showed me how much downhaul u need and showed me how to set up properly so ill delet that post
im to inexperienced to give advice at the moment the best thing for me is just to listen and learn.