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post #1 of Old 04-29-2004 Thread Starter
Brian Hancock
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Considering a New Mainsail

Sail shape is the most obvious indicator of whether or not you need a new mainsail. If the sail is wrinkled along the leech and baggy in the center, chances are you need a new one.
Here's a common scenario this time of year: Let's say your old mainsail has developed a familiar, soft feel from many years of good use. From a distance, the shape still looks OK, but the problem is that up close you can see those wrinkles radiating out from the corners, and when the light is just right, the sun shines through the stitching holes. You're thinking seriously about a passage to Bermuda or even Mexico next summer and it's natural to wonder if your "old friend" will be up to the trip. So how do you know when it's time to replace your mainsail and invest in a new one? And what do you need to look for in the new sail? The process can often be more daunting than buying a new car, and for bigger boats, just about as expensive.

First let's take a closer look at your old sail just to be sure that it's actually past its prime and ready to be turned into duffel bags for the crew. The most obvious indicator is sail shape. If your sail has developed those middle-age symptoms from which most of us suffer—a fat belly and a tight leech—it's either time for a recut or for a new sail. But deciding what option to take can be difficult. It's hard to gauge how much life is left in old sails, but there are some things you can do to determine the sail's essential value.

Generally, the first thing to go with old sails is the stitching. The UV rays in sunlight rot thread, and when combined with frequent chafe, it turns these strands into the weak link in the sail. Take an awl, or some implement with a sharp point, and poke it between the stitching and the fabric. If the threads break easily, you probably need a new sail. If you have to pull at them and there is some resistance, your sail probably has another season left in it—unless of course you are headed offshore for some blue water passage-making, in which case you probably don't want to take the chance.

Even high-tech laminated sails will suffer from UV deterioration, so check the stitching and see what shape it's in.
Next, take a look at the fabric. Most DacronTM sailcloth has a life of three stages. When it's new, it has a firm feel from the resin that fabric makers use to impregnate the yarns as a way of combating bias stretch. After a season or two the resin breaks down and flakes out, and the sails develop a softer feel. The yarns settle in, the fabric stops stretching, and for the next few years you have a nice, stable, manageable sail. Then UV starts to take its toll. It's a slow but sure process, which over time makes the fabric stiff and brittle. Again, take your awl and poke a hole in the sail. If the yarns have some elasticity and move aside for the point of the awl, then your sail has some life left in it. If the yarns are brittle and break, it's time you got a new one.

Assessing the life left in a laminated sail is a little more difficult. The stitching remains the weak link, so you should perform the same test as you would on a DacronTM sail. If the stitches are rotten, then the sail is no longer useful. The most obvious sign that the fabric is nearing its end of its useful life is if you see delamination; otherwise, on principle, you should replace the sail once it starts to look old and tired.

"Once you have a better idea of your goals, it will be easier for you to get the right mainsail for your needs."
OK, let's say you've made your decision and you're going to get a new mainsail. Now, consider if you want one just like the old one or if you want to take advantage of new ideas and new technologies. The first step is to ask yourself these two important questions: What kind of sailing do I plan to do, and what is my budget? Both answers will influence your purchase decision. Do you normally stay close to the coast and take short day trips, or do you head for distant horizons and blue water, or even race occasionally? There are subtle differences in the design and engineering of sails depending upon how they will be used, and you want to be sure that you take full advantage of what's available. Once you have a better idea of your goals, it will be easier for you to get the right mainsail for your needs.

Next, ask your sailmaker about fabric choices. This will be the single, most important feature of the new sail and will determine the panel layout and price. In an earlier article (Panel Layout and Fabrics), I discussed the merits of woven DacronTM and laminated PentexTM, and how the fabric choice determines the panel layout. It's worth pointing out again that an investment up front in better fabric and better sail engineering will pay dividends down the road, so be sure that you have all the facts before you make your decision. Laminated fabrics are used radially in the sail and have better strength and stretch characteristics than DacronTM. And with these fabrics, the sailmaker can engineer the sail to be lighter and more manageable. This becomes more evident and necessary in bigger boats where the loads are higher and heavy sails more difficult to manage. As a rule of thumb, boats bigger than 40 feet should start giving serious consideration to a laminated fabric, especially if they're heading offshore.

If you are getting a new sail, consider one with additional area in the roach (upper leech) like the one on the author's own boat here. It can be a good move particularly if your boat suffers from a lack of weather helm.

Once you have decided on fabric, spend some time thinking about sail size and handling techniques. It may be that your old sail was perfect and you want to duplicate it. If that's the case, pull out your tape measure and start measuring. Get accurate luff, leech, and foot dimensions, and pass them along to your sailmaker. Measure the reef heights and take note of the luff attachments. The more details you gather, the easier it will be for the sailmaker to build an identical sail. Remember, however, that this is the time to improve on the old sail, so give some thought to new ideas.

How is the helm on your boat? Is it balanced or can you use more weather helm? Or ask yourself if there are there other indications that your boat could stand more sail area. If you add area to the roach of the mainsail you can increase the performance of the boat, but you will also increase the weather helm. Also, if you have weather helm, ask yourself if it's because the old sail is too full; or lee helm because the old sail is too flat? And don't forget, it's the back of your mainsail that works with your keel to provide lift when you are sailing to windward. It's critical that the leech stands straight and does not cup to weather. Also, what about reef heights? Does that first reef sufficiently reduce sail area? Is a single, large reef better than two small ones for the kind of sailing you ordinarily do? And how about adding a third reef for that transatlantic passage that's still a few years down the road? Considering the answers to all of these questions can help you define your new sail, so ask them and answer them, and then run them by your sailmaker.

Another feature to consider is having full-length battens in the upper leech of the sail. This sail could benefit from that application.

Once you have probed the questions of sail size and shape, think about handling. Unless you are seriously considering the possibility of using the foot of your mainsail for catching fresh water in the tropics, I recommend that you consider a loose-footed sail. This arrangement can provide more adjustment and you'll have less of an issue with slides breaking. Also, adding lazy jacks or another system to make dropping the sail easier is something to think about. And new luff hardware might be an option you'd like to think about so that the sail slides up and down more easily. Another consideration is having full-length battens up high in the sail to support the roach and take the flap out of the sail when reefing and dousing.

There are many new ideas that you can incorporate into your new mainsail. It's principally a matter of asking the right questions, but if you understand clearly what your objectives are, you will end up with a sail that better serves your needs and lasts many seasons. Don't forget, it's called the mainsail because it is, after all, the main sail in your inventory.

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