UV Protection For Roller Furling Sails

Several readers have asked how to best protect the exposed part of headsails when they are roller furled.

The traditional answer to this problem is to sew a strip of UV-resistant Sunbrella along the leach and foot. But I have an abiding hate, going back over 40 years to when I was a sailmaker, for this solution. Here is why, along with some better ideas: 

  1. Six Reasons To Leave The Cockpit Often
  2. Don’t Forget About The Sails
  3. Your Mainsail Is Your Friend
  4. Hoisting the Mainsail Made Easy—Simplicity in Action
  5. Reefs: How Many and How Deep
  6. Reefing Made Easy
  7. Reefing From The Cockpit 2.0—Thinking Things Through
  8. Reefing Questions and Answers
  9. A Dangerous Myth about Reefing
  10. Mainsail Handling Made Easy with Lazyjacks
  11. Topping Lift Tips and a Hack
  12. 12 Reasons The Cutter Is A Great Offshore Voyaging Rig
  13. Cutter Rig—Should You Buy or Convert?
  14. Cutter Rig—Optimizing and/or Converting
  15. Cruising Rigs—Sloop, Cutter, or Solent?
  16. Sailboat Deck Layouts
  17. The Case For Roller-Furling Headsails
  18. UV Protection For Roller Furling Sails
  19. In-Mast, In-Boom, or Slab Reefing—Convenience and Reliability
  20. In-Mast, In-Boom, or Slab Reefing —Performance, Cost and Safety
  21. The Case For Hank On Headsails
  22. Making Life Easier—Roller Reefing/Furling
  23. Making Life Easier—Storm Jib
  24. Gennaker Furlers Come Of Age
  25. Swept-Back Spreaders—We Just Don’t Get It!
  26. Q&A: Staysail Stay: Roller Furling And Fixed Vs Hanks And Removable
  27. Rigid Vangs
  28. Rigging a Proper Preventer, Part 1
  29. Rigging a Proper Preventer—Part 2
  30. Amidships “Preventers”—A Bad Idea That Can Kill
  31. Keeping The Boom Under Control—Boom Brakes
  32. Downwind Sailing, Tips and Tricks
  33. Downwind Sailing—Poling Out The Jib
  34. Setting and Striking a Spinnaker Made Easy and Safe
  35. Ten Tips To Fix Weather Helm
  36. Running Rigging Recommendations—Part 1
  37. Running Rigging Recommendations—Part 2
  38. Two Dangerous Rigging Mistakes
  39. Rig Tuning, Part 1—Preparation
  40. Rig Tuning, Part 2—Understanding Rake and Bend
  41. Rig Tuning, Part 3—6 Steps to a Great Tune
  42. Rig Tuning, Part 4—Mast Blocking, Stay Tension, and Spreaders
  43. Rig Tuning, Part 5—Sailing Tune
  44. 12 Great Rigging Hacks
  45. 9 Tips To Make Unstepping a Sailboat Mast Easier
  46. Cruising Sailboat Spar Inspection
  47. Cruising Sailboat Standing Rigging Inspection
  48. Cruising Sailboat Running Rigging Inspection
  49. Cruising Sailboat Rig Wiring and Lighting Inspection
  50. Cruising Sailboat Roller Furler and Track Inspection
  51. Download Cruising Sailboat Rig Checklist
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bill koppe

Hi John,
I had a sleeve on a 45 ft cruising yacht with a short mast.
The sleeve needed the sheets tied around the sail so it could go over them.
With the sheets bent on with bowlines this was a problem and often need a boat hook to assist .
The sleeve was tightened by a line passing through alternate loops.
With high winds the sleeve would flap, even after retightening.
There was an area at the head and foot that still was subject to sunlight, partly as a result of the large diameter mentioned above for the sheets.
I would not recommend sleeves.
For a genoa I would have a strip and like you would stick with dacron.
For a staysail there is a lot to be said for a hanked on sail and a deck sail bag.
Bill Koppe

Marc Dacey

This is what we have, a nanked-on stay sail. Lives in a knotted bag in the anchor well and seems in good shape. I am considering either replacing our yankee-cut jib topsail (with the dreaded Sunbrella trim in Nova Scotia next fall, so it’s good to have an implicit endorsement for area around Halifax. The 303 spray tip is most welcome, and easily done.

Dick Stevenson

Hi John,
Good advice, nicely put. We do as you do for the reasons you describe.
Another thing about Sunbrella, for the use you describe and especially those who use it for a mainsail cover, is that it loses its capacity for UV protection over time, usually less time than one supposes. Hold a few-year-old piece of Sunbrella up to the sun and it will become apparent. If the piece has been in the tropics, you might get a sunburn through it and your mainsail will certainly suffer. A few-year-old Sunbrella will also allow water through making the sail sit soggy and wet and allow dirt through. Dan Neri in his excellent book, “The Complete Guide to Sail Care and Repair” (although it may be dated now) speaks to Sunbrella breakdown in more detail as well as do other authors.
For the last 13+ years or so I have used vynilized Sunbrella for my mainsail cover (no longer available, I believe). It has been bulkier and heavier, for sure, but even as ratty as it is, it remains perfectly opaque and so does the job of keeping sun off the mainsail. It is falling apart at the edges, so I am getting a new one made and will go with Sunbrella Plus: a fairly new product in the Sunbrella line which promises better attributes for UV and waterproofness. It will be easier to handle and lighter and I will see how it holds up. I plan to “303” at least yearly: maintenance un-necessary with the vynilized Sunbrella.
303 is a great product (although not inexpensive) with many uses on a boat and has served Alchemy well.
When I last had sails made, the Gore-Tex thread came up as an option (not sure now whether it was the same thread you refer to), but the sailmaker reported that the thread was so abrasive and tough that it ate up his machines and needles, so we went with more conventional thread. This has been fine as we have been up north.
I had never seen the “sleeves” until sailing in Europe. Watching skippers putting on the sleeve, especially in a bit of the late afternoon breeze, was always entertaining. And, not infrequently, the top few inches were left exposed.
My best, Dick Stevenson, s/v Alchemy

Marc Dacey

Having a newish mainsail cover, I wonder if there’s a way to, post-purchase,”vinylize” the inside of it to preserve the opacity? Some sort of “mackintosh” process, which was essentially rubber-coated cloth that didn’t crack. Like you, I’m not so concerned with the ratty-looking part as I am about keeping the mainsail sequestered from mould and sun when stowed away.

Dick Stevenson

Hi Marc,
Some I know have, after a few years, sewn an extra layer of Sunbrella on the inside of the mainsail cover just on the top 2/3rds of the cover that gets the most intense sun. I know of no vinylizing that would work (but have never looked into it). I do know that the vinylized Sunbrella was mostly used for Bimini tops and full enclosures for the most part. I believe they have a new product to meet these demands but it felt too much like plastic to me, so I am going with the new Sunbrella Plus which has some coating on the inside (polyurethane, I believe) which is modest enough to allow the material to be handled like regular Sunbrella.
My best, Dick Stevenson, s/v Alchemy

Marc Dacey

Dick and John, thanks for the replies. A “petticoat” of more Sunbrella makes sense…and avoids the mildew aspect.

Dick Stevenson

Hi John,
Agree, especially if the sails are laminate. One of the considerations when I went for HydraNet radial cloth was that it was a woven product and would do more breathing, With the vinylized mainsail cover, when the sail was damp/wet, I just draped the cover over the sail leaving the whole underside un-attached and open. In this way, over 3-4 seasons now (mostly in damp & wet UK) I have not had any mold or mildew. I think laminate sails would have a harder time.
My best, Dick Stevenson, s/v Alchemy

Brian Smith

No, it doesn’t need to cause mildew. I (and now several of my sailing friends) have been using 100% vinyl boom covers for about 30 yrs, what’s more I weld the seams making them completely air and water proof. The trick is to make them sit like an inverted U. I attach quick release plastic buckles along the inside equator which firmly hold the cover in place but leaves the bottom of the sail open to the air and breeze, thus well ventilated but out of sun and rain.It’s a little heavier to fold away than brella etc but very quick and easy to deploy.It also lasts years, and years, and years.

The boat right next to mine in the marina ( hadn’t been used for 12 months ) removed his conventional boom cover last week to reveal a mass of mould, so the climate here is far from dry……

Philip Waterman

I had my “sacrificial” protection replaced with a vinyl coated acrylic weave last year. I don’t know the brand but it wasn’t Sunbrella. The sailmaker said is will outlast the sail – even in the vicious Southern Med. sun and heat – time will tell. It was expensive compared with an acrylic only fabric and is a fairly stiff material. This seems to help the sail shape but does add bulk to the furl.

I have used Tenara thread (which is suposedly UV/heat stable) for my spray-hood, sail covers, etc. It is too early to see if it does what it says on the tin and outlasts the Sunbrella. I would expect Gore Industry’s to be pretty honest with the spec. so it bodes well. There are fabrics woven with Tenara. I have only seen heavy weaves for use as a stuctural fabric, for example in the roofs of sports facilities where there is a desire for minimal weight and maximum transparancy to daylight. A lighter woven Tenara fabric might be an interesting prospect for UV protection. Now if the fabric was suitable to make a sail they would really be on to something.

Ted Scharf

I raced on a boat that used a sleeve and it worked well. It had a zipper so had no open spots. I also liked that there was no way a sail was going to open in the wind with it on. With 2 people it was easy to put on and one person could do it. Just a little more work. Each to their own.

Jim Ferguson

We have been in Europe the last ten years and now that we are in the Med, we have found our sleeve to work wonderfully during winter storage. Every third year we leave both it, the genoa, and the mainsail with a local sailmaker for an inspection and tuneup. So far no complaints.

Dick Stevenson

Hi Jim,
I have never been able to nail down estimates from Sunbrella and their vendors, but I would want you to consider that your sleeve’s usefulness for UV protection as a winter cover in the Med may be quite compromised after only a few years. I also wonder whether it is good for a sail to have that kind of halyard tension on at all times. Perhaps you “relax” halyard tension when not in use: something I do on a regular basis even during the season.
My best, Dick Stevenson, s/v Alchemy

Steve

John,
I don’t know if I heard this 100% correctly, and your North friend didn’t make mention of it. However, when we were at Annapolis’s Cruisers University one of the Presenters said that the new All Carbon sails – though 2-3X more expensive had three big advantages – much lighter than any other sail, 100% UV resistant and it will never lose shape – period. Its only enemy as in all sails is Chafe.
North is touting its Carbon 3Di has done 50,000 miles on one of the big French performance Tri’s – the name escapes me – and is doing its 3rd race on the same Main around the world.
We have ordered a boat perf/cruising cat and 3Di is the sail we are going to specify for most of the inventory – having seen the shape loss in other ‘performance cruising sails’ on friends Cats – with less than 10,000 miles -the upfront expense seems justified by shape holding, weight savings (40% lighter), and UV resistance all equating to 2-3X longer service.
I would still of course cover the Main, and will look into the ‘Sticky’ solution on the Headsail – but a sock seems the better solution – as long as it is cut ‘tight’ to avoid the afore mentioned flapping – we will pull it up with the Spin Halyard so the top will be fully covered as will the bottom of the sail. On our current race boat, with ‘delicate’ laminated sails I had the sock made to fit snug and have 3 -2″ wide and ..75″ thick full length foam inserts glued into the interior – more to keep the cover from direct contact and heating the Mylar laminate – which degrades it quicker than direct sunlight according to our sailmaker here (not North). We race/sail 3-4x a week so we leave our Mylar Headsail up so we can get to the start line on time and the Bar sooner – so protection is crucial in So Cal sun so we put a a sock on it – and without help it takes literally 2 minutes.
Thanks for the continual flow of great information

Simon Wirth

Hei John
While I cannot comment on sails from North Sails, my family and I have been using North Sails Windsurfing sails for a good 3 decades now, so basically since they started to change over to foil sails. What I can tell from personal experience using them in the sand and sun of the Mediterranean is that their UV resistance drastically improved over that period.
I had the luck to get a chance to try out one of their prototype sails they built from sailboat materials about 6 or 7 years ago, and this sails basically spend their time in the open sun all season. The current generation of sails seems to survive 1-2 seasons out in the sun all day long without noticeable degradation from UV. It’s now actually the way you describe it, that the stitching tends to break first.
All in all, I’d also be skeptical about any 100% resistance claims, but it now seems to be a general “aging” problem, comprised of a combination of just age, heat and UV that kills the materials, and not just the UV “cooking” the sail to bits.

Ralf

John,
on the Genoa of my previous boat (sailing in the Baltic) I opted for another solution that met most of my needs, with not being cheap as a downside. My sailmaker in Germany called it Coverbrush ( https://www.segelwerkstatt-stade.de/coverbrush-uv-schutz/ ). It’s a system where they print some layers of UV resistant paint on the area the UV protection is usually stitched on. It worked well, I didn’t have to get the paint repaired or renewed in the three years until we sold the boat and bought our Flora, Though still being in contact, I heard of no complaints from the buyer who now sails the boat in Italy, so it should still be working.

John Neal

John,
Have you heard of Top Gun, a polyester duck (acrylic-coated) fabric intended for boat covers and sun awnings? We’ve been averaging 50,000 miles and 5 years in both tropical and high-latitude sailing WITHOUT having to restitch or replace, twice what we’ve ever had out of UV-coated Dacron sailcloth or Sunbrella. It is rated for 16,000 abrasions. We use it for: UV genoa cover, chafe protection sewn over where any batten can chafe on shrouds and for our full boat cover. Our boat cover is now 15 yrs old and the Top Gun is no longer waterproof where it has rested and rubbed on the dodger and boom, but still protects from UV and debris. Sailrite has a good selection and good prices.

Francis Clouston

Our sailmaker recommended we use Swiss-made Stamoid Light by Ferrari Textiles when we replaced our genoa in 2011. It’s a PVC/polyester fabric made with different weights and levls of UV-resistance for a variety of applications such as sailcovers, biminis, etc. It’s heavier than Weathermax (300 vs 250 g/m sq.) but it doesn’t seem to be so heavy to misshape the sail. We’ve been sailing eight years now with these sails and the strip looks almost like new.
Don’t know about the price but I did’nt get a price-sticker shock when I got my sailmaker quote (something rare in the boating business, as you know) and I assume it is relatively to sew on.
Unless my sailmaker suggests otherwise next time my sails need to be repaired or replaced, I’ll probably use the same product again.

Marcelo

John
I have the sticky-back dacron on my head sail and it is now in need of cleaning (it is white). It is also all “cracked”. I could not find a proper way to clean it and I was thinking of replacing it, but not sure if I can remove it without damaging the sail.
You mentioned that “Either way, most of us will probably need a complete rehab of a Dacron sunshield once in the life of a headsail…” Do you know of a workable way to remove the damaged one? Or, can you just stick a new one on?
Also, another purpose for the 303 Aerospace Protectant – spray it on a cloth and rub on the opening port rubber gasket to prevent it from sticking and prolong the gasket life.
Cheers
Marcelo

Drew Frye

After numerous conversations with both sailmakers and paint manufactures, This summer I started trials on paint for UV protection. This includes many test panels, as well as sail trials, and will take years. More than a few low-budget sailors have turned to house paint (probably not the best choice) as an alternative to a new ($$) fabric cover, particularly if the sail shape was already beginning to go. To them, it made more sense to save the money towards a new sail. We are also seeing painted sails on VOR boats and the like, which is really for advertising more than protection, but they are claiming both. Finally, as you pointed out, fabric covers on laminate sails are a problem. The cover can make a hinge where tears like to start; this is the real inspiration for the project. I had two laminate sails that suffered terribly from tears at the edge of a poorly installed UV cover.

A few early observations, my own and from others:
* I’ve used paint on an inflatable, and it held up well to flexing.
* I’ve used paint on awnings. A white top really cuts the heat.
* Dark colors block a LOT more UV than white. This is true of paint and all fabrics. The sole exception is aluminum paint, which is opaque.
* Adhesion is better on taffeta than Mylar.
* Paint is lighter than even UV Dacron… but when multiple coats are considered, not quite as much as you might think.

I’ve not been impressed with UV Dacron for cruising sails. I’ve had the covers burn off a few sails, though it did take 10 years. Perhaps it is because I am farther south. Certainly I don’t log enough miles–I should be wearing the sails out faster, althrough these were exceptionally well made. The UV blocking is also, I believe something like 1/2 that of dark Sunbrella. My observations, and everything is compromise. My most recent sail purchase has SA UV Dacron, over laminate, proving I’m not hard-line.

And yeah, the 100% UV resistance comment is BS. I’ve had carbon sails, and although the fibers are durable, as you correctly pointed out, that is seldom what actually fails. It is the Mylar and the glue.

Drew Frye

I just checked some of my panels (8 months). I was not surprised to see house paint (Benjamin Moore) beginning to flake in spots. The sail paints and inflatable paints were all adhering tightly and did not crack when flexed and folded hard.

My intention is after ~ 2 years, to set then as flags on the roof of my car and drive around for a while. This is crude flutter test, but one I have used successfully before. Untreated cloth is the control.

Neil McCubbin

We started with a sleeve when we changed from piston hanks to roller furling in 2010. It was a PITA. Hard to set up, flapped in strong winds and bulky to stow. Too tempting to not use it every day. We had a Sunbrella strip sewn on in 2014, and find it OK
Our 2004 Sunbrella Dodger made by Hallett in Maine, is now about shot, after 6 month/year use, from Maine to the Arctic to the tropics. We have fairly heavy stuff, and have just asked Hallett to replace it.

Denis Foster

Hello,

Thank s for all this practical real world information, always so useful.

When I look at our furling genoa I see a 10cm wide strip of UV protection. Then on the leech there is a 2cm wide ribbon that is stiched over the actual UV protection (Sunbrella, Weathermax etc….)

This small and thin ribbon on the very leech of the sail seems to be the first suffering from UV and wear. What do you recommend for this leech ribbon?

Thank s

Denis

Denis Foster

Thanks John for your Reply.
It seems to be some lightweight Dacron. The seem thread was probably chafed by the end of the spreader. It seems ton contain the leech tensioner “ nerf de chute”.
I could send a picture but I don t know the procedure.
Regards
Denis

Patrick Genovese

What happens when the stickyback UV protected dacron needs replacing? Does it come off easily?
Rgds
Patrick