Is a Mylar window a good idea?

Thread starter #1
Hello all,

First post here. Thank you to all the contributors. I have learn a lot in the past few days!

I am about to buy a new NeilPryde sail for my Sunfish. Just for fun and leisure. With 30-40 hrs of sailing per years, I am hoping it will last 10 years. The possibility to add a window sounds appealing. Living in Canada, I am wondering about its durability. A NeilPryde rep is telling me that Mylar may becomes brittle and cracking in cold weather. But cold is relative. I doubt I will be sailing below 10C (50F). Am I ok with a Mylar window?

Also, I am not 100% convince that even in warm weather, the UV protection on it will last a decade.

Any experience to share?
 

beldar boathead

Well-Known Member
#2
I think only Neil Pryde uses mylar so there won't be much info on that, but windsurfer sails - the clear ones - are mylar and I think they last a long time.
 
Thread starter #3
Thank you beldar, this is very appreciated. I will ask around on a windsurfer forum.

EDIT: you now make me wondering! Why are they the only one using Mylar then? Is this a non-compliant class rule upgrade for leisure sailors... or a downgrade?
 
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andyatos

Active Member
#4
The clear material you see on windsurfing sails is monofilm which is quite strong and has very little stretch. There's also X-Ply reinforced monofilm for areas where there is a lot of tension, like the luff of a windsurfing sail.

The problem with monofilm though is if it is folded, it leaves a permanent crease in the material that can fatigue over time and crack. That's why all windsurfing sails are rolled and put in bags when stored.

The windows you see in Sunfishes and Lasers tend to be vinyl which is a much more pliable clear material that can be folded and not crease. I just got a brand new Intensity Sunfish sail ($125) a couple of days ago and the window feels like it's vinyl.

In any case, if your window wears out, it's a pretty easy matter to have the window replaced by someone at a sail loft. Here's a video on how to do it.

Cheers,

- Andy
 

andyatos

Active Member
#7
The Neil Pryde web site says, "X ply laminated mylar" when referring to their Sunfish sail window. So, yes... that's the "black cross stitching".

- Andy
 
Thread starter #8
NeilPryde confirms that it must be loosely rolled, never folded.

I imagined myself stressing out every time I put the sail and mast in the rig sleeve at the end of the day and decided to go without it. I never had one so I won't know what I am missing.

Thank you all for your inputs. Great community.
 

L&VW

Well-Known Member
#9
Hello all,

First post here. Thank you to all the contributors. I have learn a lot in the past few days!

I am about to buy a new NeilPryde sail for my Sunfish. Just for fun and leisure. With 30-40 hrs of sailing per years, I am hoping it will last 10 years. The possibility to add a window sounds appealing. Living in Canada, I am wondering about its durability. A NeilPryde rep is telling me that Mylar may becomes brittle and cracking in cold weather. But cold is relative. I doubt I will be sailing below 10C (50F). Am I ok with a Mylar window? Also, I am not 100% convince that even in warm weather, the UV protection on it will last a decade. Any experience to share?
Before it tore in a violent cell-storm, I had an official vintage racing sail from Florida. The window eventually turned yellow :(, then an opaque dark brown. :confused: (And this, in the northern-tier state of New Hampshire!)

SunfishBlousedMainsail.jpg
 

beldar boathead

Well-Known Member
#10
Have you considered a sail other than Pryde? While offering fewer colors, aps and Intensity offer vinyl windows and the price is great.

I've seen many, many, many older Sunfish sails with vinyl windows that are fine. Light and Variable seems to have had a very unusual case of bad luck with his window.
 
#11
I second the Intensity sail recommendation. Not race legal, but the sail I purchased (w/ window) is very well made and has held up well.
 
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