|This is a topic that pops up from time to time; many people will be thinking about this as winter-discount time approaches. I thought this was a good response as it offers some reasonable tests you can apply to the structure of a sail (another one I learned a long time ago is that if you push a sailmaker's needle through dacron and the threads break instead of moving aside, you're way past the 'replace-by' date).
Assessing the shape of a sail that appears to be superficially acceptable is harder than assessing the structure. My suggestion is to take the sail to a sailmaker. Despite what many think, sailmakers tend to be generous and won't recommend a new sail if they think you're reluctant unless your sail is really, really shot. I'd like to reinforce two points (one of which he did not make explicitly): letting sails drag across the spar or rigging is pointlessly harsh - don't let your headsail back beyond a third of its length when tacking and fit shroud rollers on the forward lowers to minimize the abrasion. Also, if you have roller furling, take to heart what he says about securing roller-furling sails; I once saw a sail destroy itself in a squall because the owner hadn't rolled it tight - a sail-tie around the headstay is good insurance.
Thanks to Dave Flynn, cruising consultant at Quantum Atlantic,
Annapolis, MD, for permission to reproduce.
How Long Do Sails Last?
By Quantum Sails
One of the most often asked question to any sailmaker is "how long will the sails last?" While there are many factors, our cruising expert Dave Flynn dives into what causes a sail to fail and what you can do to ensure you get every hour out of you sail!
This is a loaded question! The answer every cruising sailor wants to hear, of course, is ‘forever’ (or at least, ‘a very long time’). In reality, the answer is more complicated, but there are two key factors in the life of your sail: structure and sail shape.
The first thing to consider is the structural integrity of your sails. Structurally, sails gradually lose their integrity as the materials and stitching fail under the influence of the sun and use. UV causes woven polyester materials (Dacron®) to gradually lose tear strength. If you can take an existing tear and easily extend it by pulling with moderate pressure, it’s over. You can fix the tear with a patch, but it will just keep on tearing in other places, often at the edge of any repair.
Likewise, if you can run your fingernail across the stitching and pick it off easily, the sail needs re-stitching. It is normal for the stitching to rot before the material in the sail; that’s why it's important to examine sail stitching periodically and re-stitch areas as needed.
The life of your sail's structure depends on sunlight exposure and how strong the UV is. Other factors include the breeze your sails are used in and how much flogging, chafe, and other abuse they receive.
A better way to think of the structural life of your sails is in terms of hours of use. A reasonably well-treated woven polyester sail that is maintained regularly will last 3500-4000 hours.
A typical weekend cruising sailor using his boat two weekends a month, plus two weeks of cruising, over a five-month season will accumulate roughly 240 hours per year – those sails will last for 16 years! At the other extreme, a person living aboard their boat and cruising the Caribbean extensively will use their sails as much as 12 hours per day, 12 days per month, all year round, for a rough average of 1,728 hours a year. This sailor will be replacing sails every 2.5 years.
The second thing to consider is shape-life. This is more difficult to assess since sail shape deteriorates gradually with every hour of use. The effect of this is harder to judge than the condition of the cloth. Sails that stretch too much become too full and can't retain airfoil shape (having a distinct rounded entry and flat, straight exit). This loss costs you in subtle ways.
Full, stretchy sails rob power in light air, but more critically, they create heel and weather helm just when we want control. At some point, we have to sail upwind – usually at the least convenient times. If sails don't have proper shape and the materials and structures are not designed well enough to resist stretch, the boat will not be able to go upwind effectively.
Unfortunately, shape-life degrades more rapidly than structural life. Sails will be triangles long after they cease resembling anything like a critical airfoil. Shape-life is very dependent on harshness of use, but even when treated well, sails can only be expected to retain good shape for only half to two-thirds of the structural life of a sail – that’s roughly 1,700 to 2,700 hours of use. Periodic recutting helps. As long as the material is in decent condition, excess shape can be removed and an effective airfoil shape restored.
Relative to much of the gear on your boat, sails do last a long time, but – unfortunately – not forever.
When you do decide to replace your sails, you'll be pleasantly surprised. Your boat will come alive as dramatically as if you had put a new engine in your car. There will be spring in her step. When the wind is up there will be a greater sense of control, and going to weather might be fun again (at least for short periods of time).
To help protect your sail investment, here are some suggestions:
Protect your sails from unnecessary exposure to sunlight and heat.
Avoid prolonged luffing and flogging.
Motor with your sails down unless they can be filled.
Never back a genoa against the spreaders when tacking.
Use the correct halyard tension. Halyard tension changes as a function of apparent wind velocity. Add just enough tension to remove horizontal wrinkles as the apparent wind increases. Ease when the apparent wind velocity drops.
Protect from chafe. Make sure spreader and chafe patches are on and in the right place.
Take sails off the boat when not in use or out of the water for any extended time period.
Periodically rinse with fresh water. Annual professional servicing and washing is recommended.
Store sails dry.
Be sure roller furling sails are well secured when leaving the boat.