Why Blue?

[Praxinoscope]

May need to renew the UV strip on my Genoa soon and I started to wonder why all these strips (or most of them) are blue, as the intention is to filter out the harmful UV (which on the spectrum is just beyond the blue).
It seems to me that it would be more logical for the strip to be in the yellow part of the spectrum which would filter not only the UV but also the upper end of the blue portion of the spectrum, far more efficiently than a blue strip.

 

[Tranona]

Bl;ue is just tradition - very nautical!. Mine is grey to match the sprayhood. You can have any colour you want out of the range of the fabric being used. There are 40 different colours in the Sunbrella range that is commonly used. Don't think the colour makes much difference to the UV protection of the sail, but might affect the strip itself.

 

[Porthandbuoy]

Mine is white. The only problem is the number of people pointing and telling me “You need a UV strip on that.”

 

[Dipper]

Mine's also white.

 

[ashtead]

The issue with blue ones is once the sail has been cleaned they look rather tired. We also have grey and seem fine after 6 years even if the original quality of the sails is not that great as by Elvstrom. If you don’t like strips maybe investigate socks as they have on Maxi1300 and such like but would seem to be a hassle to hoist after every sail.

 

[Neeves]

The Cat next to us has a yellow UV strip, I've not been privy to the life, nor have noticed - but it seems no better worse than any other colour (mostly blue, one yellow, one green and a few red, lots of white (as is ours).

Jonathan

 

[Caraway]

This refers to polyester material

Dye colors that have longer wavelengths react with UV light, which comes from the sun, in negative ways. These colors have less energy, causing the chemicals in the dye to break down.

Red is the color that tends to fade the most, followed by orange and yellow. Red has the longest wavelength of all the dye colors. It will lose its vibrancy faster because it absorbs more of the UV rays from the sun.

What Color Fades the Least in Sunlight?
Dye colors with shorter wavelengths have more energy. These colors have a greater tendency to resist fading. They also have more energy and don’t absorb as much UV light.

Purple and blue will fade the least in sunlight. Purple dye has the shortest wavelength of all the colors, followed by blue and green. While green doesn’t fade as much as red, orange, or yellow, it isn’t as resistant to fading as blue or purple.

The UV resistence is a different issue. Sunbrella materials still fade. That is the pigment issue in dyes.

UV covers are strips of sacrificial fabric (we use a specific Sunbrella fabric) that absorb the UV rays and keep them off of your sail. UV covers are commonly used on furled headsails and on heads or clews of mainsails that stick out when furled in mast or in boom.

The Invisible Sail Killer: UV Rays

 

[HissyFit]

The UV strip is not acting to filter UV light, it just blocks it. Any material will do, but some materials will do better as they will not sacrifice themselves too quickly.

As for colour, I'd go for a mid grey as it is the colour of the dirt/salt spray that will cling to it, so it won't show the dirt. This is why silver and grey cars are more popular than black or white ones (certainly with me).

 

[thinwater]

The simple answer is to Google Sunbrella UV Transmission.

 

[Eeyore]

+1 for white. Mine is Weathermax 80.