Ask Your Sailmaker | Cruising World

Ask Your Sailmaker

How Long Do Sails Last? And the corollary: What Can I Do To Take Care of Them? David Flynn from the Quantum Sail Design Group weighs in.

Quantum Sail Design Group

David Flynn of Quantum Sail Design Group recommends polyester composite sails for a Valiant 40 and a more high-tech fiber composite for the Passport 545.

Courtesy of Ralph Naranjo

How Long Do Sails Last? And the corollary: What Can I Do To Take Care of Them? The first is a loaded question. Let me start with the politic answer, the one every cruising sailor wants to hear from their sailmaker: why forever, of course. Well, maybe not forever, but for an awfully long time!

In reality, the answer has two parts. The first is from a structural standpoint, or, how long will it remain intact as a triangle? The second half of the answer relates to sail shape. How long will the sail function as a critical airfoil, capable of driving the boat well and being effective upwind? This is the tougher part of the answer. As a triangle, sails will last for a surprisingly long time. It is not uncommon to find sails still in use that are 10-15 years old. Structurally, they gradually lose their integrity over time, principally as the materials and stitching fail under the influence of the sun. UV causes woven polyester materials (referred to generically by the trade name 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, so it can be re-stitched, and should be periodically during its lifetime.

How long this process takes is obviously heavily influenced by how much sunlight, and how strong the UV is to which they are exposed. Other factors come into play, including amount of breeze in which they are used, how much flogging, chafe, and other abuse. Ultimately, a better way to think of the structural life of a sail is in terms of hours of use. A reasonably well-treated woven polyester sail that has been maintained regularly will last 3500-4000 hours. This means that if you are the average New England cruising sailor, who each year uses their boat two weekends each month of a five-month season, with an additional two full weeks of cruising thrown in, for a total of roughly 240 hours per year, your sails will last for 16 years! At the other extreme, live aboard your boat and cruise the Caribbean extensively and you might use your sails as much as 12 days per month (12 hours per day) all year round, for a rough average of 1728 hours a year, and you will be replacing sails every 2.5 years. Do the math and you’ll get the idea.

The shape-life of a sail is more problematic, since it deteriorates gradually with every hour of use, and the effect on performance is much harder to judge than that of a sail which won’t stay in one -piece. Sails which stretch too much, become too full, and will not retain a critical airfoil shape (with a distinct rounded entry and flat, straight exit), cost you in more subtle ways. Let me read your mind; I know what you are thinking. “I’m just a cruising sailor, I don’t care about performance.” Actually, you do, it’s just that “performance” is based on a different set of criteria. Yours is not the quest for another tenth of a knot of boat speed or one degree of pointing. But it is critical to control heel. Full, stretchy sails, rob power in light air, but more critically, they create heel and weather helm just when we want control. Also, lets face it, at some point, we all have to sail upwind; (usually at the least convenient moments). After all, a bathtub with a sheet can go downwind. One of the real luxuries of a good cruising boat is the ability to go upwind when necessary, and for most cruising boats this goes against the grain of much of their design criteria. If sails are not shaped properly, and their 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 good sail shape can only be expected to be only half to two -thirds of the structural life of a sail. How much deterioration you are willing to accept is largely a subjective matter. Periodic recutting helps. As long as the material is in decent condition, excess shape can be removed and an airfoil shape restored.

The good news is that relative to much of the gear on your boat, sails last a long time. They do not, unfortunately, last forever. However, you will be pleasantly surprised when you replace them. 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 just be fun again (at least for short periods of time).

To help protect your investment, here are a couple of thoughts:
· 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 to remove horizontal wrinkles) tension 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.

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