amazing how many time coros comes up...

everytime i see a broken sail i think, "there goes another flight to coronation beach"

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aeroegnr said..

Gestalt said..
Was a body part involved in the destruction.

A sharp, sail-seeking knee

Would the sail be OK if you put a cork on that sharp knee ?

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mathew said..

MarkSSC said..
I wonder if the most proactive thing we can do is to work out how much life is added to a sail by using the crossply panels. My observation is that there is a substantial increase in the life of a sail simply by having crossply panels

^^ this. Sort of.

X-ply does crack, but those cracks tend to not puncture. Monofilm cracks, then punctures along the crack.

X-ply has one particular downside -> it distorts the view. This never really bothered me until I tried ariel-off-the-lip where I couldn't judge the the whitewater.

I've been saying for a few years now -> what we need is x-ply without the thread. It is the glue-layer that allows the partial cracks to not puncture, while also not being distorted.

Every material has a life expectancy. Fatigue cracking was something peculiar to the aircraft industry when the materials they were using cracked and failed due to the stresses involved in general use. With that in mind, the continual bending, stretching and flexing of the monofilm may be the catalyst for eventual failure. Other factors are also involved, like the brittleness caused by the sun and unexpected large objects (people) impacting the surface. I still think, because there is a lot of variation in how long each sail will last, that stress fatigue has a part to play. I am not sure that your thesis about the laminations is valid, because laminating a surface always leads to greater strength. The advantage with laminations is that one layer can be damaged, but not compromise the structure. A crack always goes through a material, but it does not mean the material will continue to tear. I think you will find that it is not the glue that stops further tearing, it is the other material that has been bonded for that purpose. Effectively, in the case you describe, the cross-ply material has prevented a crack from developing further, maintaining the integrity of the sail.

I bought some monofilm years ago to do some repairs, never used it until recently I ran out of raceboard sails and was forced into giving repairs a crack, worked well, sewed in a whole new window to a 9.5 RB sail. I am sure a smaller freeride sail repair would be easier.

Anyway I bought thick monofilm way back then, it feels so much more durable than the monofilm typically in modern sails, in particular NP and Duotone.

I get monofilm has a used by date but using the thinnest (cheapest) monofilm available is the reason they fall apart so fast

Sails last years in UK
A sailmaker told me 1 hour in Tenerife was like 10hours in UK. If you're in Oz I guess it's trashed as soon as it's out of the bag

Sailmakers only use monofilm because the public want it.

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AUS4 said..
Sailmakers only use monofilm because the public want it.

What are the alternatives? I would also like to know what sort of plastic monofilm is. I have an inkling that it is very similar to the plastic used in Coke bottles.

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MarkSSC said..

AUS4 said..
Sailmakers only use monofilm because the public want it.

What are the alternatives? I would also like to know what sort of plastic monofilm is. I have an inkling that it is very similar to the plastic used in Coke bottles.

It is polyester.

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MarkSSC said..

AUS4 said..
Sailmakers only use monofilm because the public want it.

What are the alternatives? I would also like to know what sort of plastic monofilm is. I have an inkling that it is very similar to the plastic used in Coke bottles.

It is polyester.

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AUS4 said..
Sailmakers only use monofilm because the public want it.

it's very good for windows

i'm not sure it's generally known that UV voids warranties with most sail brands.

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sheddweller said..

MarkSSC said..
What are the alternatives? I would also like to know what sort of plastic monofilm is.

It is polyester.

AUS4 said..
Sailmakers only use monofilm because the public want it.

It would appear that Ezzy don't use monofilm anymore. www.ezzy.com/rig-support/sail-materials/

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aeroegnr said..
Just blew through the reinforced foot on one of my favorite sails. Not quite 2 years but almost. I was thinking, it's just a tack on a small board what could go wrong.

Reminds me of my friend 11 years ago.

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jn1 said..

aeroegnr said..
Just blew through the reinforced foot on one of my favorite sails. Not quite 2 years but almost. I was thinking, it's just a tack on a small board what could go wrong.

Reminds me of my friend 11 years ago.

Wow yeah that looks like almost the same spot. And he fell again! Glad I was closer to shore than it looked like he was.

Yeah, it's a sharky spot. Solid summer seabreezes there though. 30kt solid.