UV Strip for Furling Sails (2023)

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AUV Strip is essentialprotection for furling sail left exposed to the sun when not beingused.

Ultraviolet rays will drastically reduce the strength of yoursails if they are left exposed.

Whilstyour main sail should be protected with a sail-cover a UVprotective strip is the usual way to keep the sun away fromload-bearing cloth in a furled headsail.

  • Material
  • Measuring the cloth
  • Method
  • Alternatives
  • Your Comments

Unfortunately though,a UV strip will compromise the shape of a reefed sail by padding out theleech and foot, thereby encouraging a fuller luff, which is why trueracing boats never have UV strips.

However, for the average cruisingsailor a lightweight, UV material sewn onto leech of a sail is moreconvenient than stowing the sails at the end of every cruise orhoisting a sock over the rolled sail.

UV Strip Material

UV Strip for Furling Sails (1)

Itis best to use a proper UV resistant cloth if you want it tolast.

You could use an ordinary, rot-proof lightweight material butit won’t last long, depending, of course on the amount of sun it isexposed to.

Acrylic is recommended because it is UV proof, but it isexpensive and heavy.

There is UV protected Dacron, but something like Sunbrellawill last longer, the down side of Sunbrella is that it isheavy.

Don’t forget that any thread you use will also deteriorate,you can get UV resistant thread but it is lot more expensive.

There is also a UV coated sticky-back lightweight Dacron whichdoesn’t need to be sewn.

The sticky-back stuff is more expensive and it does not lastas long as some of the heavier materials.

The other problem with sticky stuff is when it comes toreplacing the UV Strip later, it can be messy.

Also it might be also worth considering the colour of the UVstrip, red pigments, for instance, are notorious for fading.

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Measuringthe cloth

Towork out the amount ofcloth needed you will need measurethe length of the leech and the foot of your sail, don’t forget thefoot.

If you are going to cut you cloth on the bias (crossways),which is best for several reasons, (stretch and sewing smallersections).

Now divide the leach length by the material width to give thenumber of sections required.

Then multiply this by the width of the striprequired.

Repeat for the foot length, which is often a much thinnerstrip.

The width of the strip on the leach will depend on thesize of the ‘roll’ when it is furled.

It should allow for turning theedges under, for some wrap around the leach to protect the edges andfor a reasonable amount of overlap when furled (9 to 10inches?).

The width of the foot strip will depend on how high the clewis when the sail is furled (2 to 3 inches?) or make it the same widthas the leach strip.

My own (very scientific) method for working out things likethat is to take my tape measure with me to the marina, find a similarlooking boat and sail and take my measurements from that.

But if you are replacing the old strip use that as the guidebut add a little so that you are not sewing it through the old stitchholes in the sail.

If you do go have a look at other boats you might notice thatmany of the UV strips are not cut ‘on the bias’ but along thegrain.

So you might be tempted to just cut your material down thelength of the roll.

You could work out the width of you strips based on the widthof the cloth, a 60" wide cloth could be cut into four strips of20”(?).


UV Strip for Furling Sails (3)

If youdo go have a look at other boats you might notice that many of the UVstrips are not cut ‘on the bias’ but along the grain.

So you might be tempted to just cut your material down thelength of the roll.

All very well if you have a sail loft and are working on anice new sail.

But sewing long lengths can be difficult if you are trying todo this at home on a domestic sewing machine.

Many of these cloths, sailcloth in particular, are as slippery and difficult to workwith as a politician, especially if using a domestic sewing machine,(not that I've ever used a sewing machine on a politician, been temptedthough).

So, working on small sections makes life much easier.

And on a large sail the extra stretchiness along the length ofthe strip (from cutting on the bias) helps keep the strain off thestitching.

However, the edges of bias cut material are more likely tofray, so when cutting the cloth use a hot knife, it will seal theedges.

And it is best to turn the edges under, it will make the edgesthicker for stitching but.....

The other thing is that many sails have a ‘hollow’ leech, onethat is slightly curved.

So, if you want to fold the strip around the leach it will beeasier to do in this in short sections.

Asyou doeach section stretch itout on a board or table, pinit or clamp it to keep it flat then use either glue or double sidedtape to hold it in place.

The glue is just to hold it in place while you run it throughthe machine, so preferably a glue that remains flexible when set andallows time for adjustment.

Removing old glue, when it comes to replacing the strip, canbe a problem.

However,one advantage ofa spray on glue over the back of thepatch is that it helps prevent the strip filling with air whensailing.

If you prefer not to use glue then some diagonal stitchingacross the strip will help reduce the possibility of the strip fillingwith air and billowing.

Before you take it to the sewing machine, pull the sail outand stretch it into its normal shape to check that that there is notension in the UV strip.

You'll need to use a reasonably good sewing machine withstrong needles.

Corners, where there are multiple layers of reinforcingpatches will have to be hand stitched.

An alternative possibility is a product called ‘Tedlar®’ thisis a Polyvinyl Fluoride Film which is made by Dupont.

Apparently it is very light weight, flexible and clear so ifyou have colored sail it will allow the colour of the sails to showthrough.

It can also be bought as a narrow sticky tape, which might beworth considering as a way of covering that trailing edge.

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An alternative to a UV Strip is to make a covering tube forthe sail, onethat is hoisted up on a spare halyard, or even something like aspinnaker snuffer to pull down.

The only problem is that you have more paraphernalia up themast, more stuff to go wrong, get tangled etc.

And these bags tend to flap and be noisy when it’swindy.

Of course you could just remove the sail each time and stow itbelow (something everyone should do if the boat is laid up for anylength of time).

But most folk would prefer to lose a bit of sailingperformance rather than lose the convenience that a roller furling orreefing system provides, so a UV Strip is the best answer.

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