Your mainsail is the workhorse of the sailing rig , therefore it tends to get the most use and abuse. Four leading sailmakers – Steve Cruse, a sales consultant with North Sails, Robbie Doyle, founder and president of Doyle Sails, Butch Ulmer, president of UK-Halsey Sails and Bob Pattison, co-owner and technical director of Neil Pryde Sails – were asked to explain what goes into the decision-making process when buying a new mainsail. Their opinions vary but their advice will no doubt help guide you when the time is right.
How can you tell when the time has come to replace your mainsail?
Steve Cruse: Every sailor has different needs and expectations for his mainsail. In general, a sail should be replaced when you are forced to make frequent repairs or when the draft of the sail has stretched so much that it is baggy, which results in reduced lift and increased weather helm.
Robbie Doyle: You should replace the main when you can't stand to look at it anymore. Racers will know it is time when they see performance suffer. Laminated sails will show signs of shrinkage at the leech and luff. Dacron sails will get baggy in the middle. And cruising sails will begin to wear out from use and UV damage.
Butch Ulmer: It all depends on how the boat is going to be used and where it is going next. If you sail the southern latitudes where UV is a problem as opposed to the northern regions, a sail will have a shorter lifespan and will have to be replaced more often. You can tell when it is time to replace the main when it has stretched out of shape. We have a downloadable program on our website that will analyze digital photos of your sail and rate its shape (see link).
Bob Pattison: When your repair cycle starts to increase you will know the sail is getting tired and needs to be replaced. You can also have a hard look at the sail when the wind is up in the 15-knot range. If there is a crease from the clew to the head at the inboard tips of the battens, then the sail has become baggy and the draft has moved aft to more than 50 percent of the boom's length.
For coastal and offshore cruising and rally sailing, what are the most essential qualities built into your new mainsail?
Steve Cruse: Offshore and rally sailors will need more durability and performance built into the mainsail than daysailers and coastal cruisers. That means either using a high end Dacron or going with a high quality laminated sail. In both cases, solid construction and UV protection are important qualities.
Robbie Doyle: The key element of a new mainsail is how well it fits your mast, boom and reefing systems. Even a well built offshore quality sail will not last long if it fits poorly. For the sailmaker, the measurements are critical as is knowing the boat and how it will be sailed. If you can't get a sailmaker onboard, take as many digital pictures of the sail as possible and take the old sail to your sailmaker.
Butch Ulmer: The force of the wind on sails varies with the square of the wind's increase in velocity so if the wind increases from 10 to 20 knots the force increases by a factor of four. For offshore sailors, who are likely to see stronger sustained winds, the mainsail has to be strong and durable. That means the sail cloth should be one or two ounces heavier than for coastal cruising.
Bob Pattison: You have to know how you are going to use your boat and where you will be sailing it. In the end, the key is the cloth you and your sailmaker choose for the sail. There are something like 500 different fabrics available to the sailmaker. I recommend that an offshore cruiser carry fewer high quality sails that are good through the widest possible wind conditions.
What type of sailcloth do you recommend for cruising?
Steve Cruse: We would look at the customer's needs first. In most cases the durability and lower cost of Dacron will be attractive. For boats over 40 feet, we often recommend higher-tech sails, such as a Spectra laminate, for this type of sailing since it holds its shape better than Dacron. If you choose to go with a Dacron sail we recommend using a higher-end cloth that has a tighter weave and is more resistant to stretch.
Robbie Doyle: For most cruisers Dacron will be the cloth of choice. There is a wide variety of cloths and price ranges. The more expensive square weave fabrics are durable and hold their shape well. Old fashioned tight weave fabrics also work well. If you are going offshore, spending a little more money on better cloth really adds to the sail's performance and durability. Laminated sails will help those who want better windward performance but they don't really make a difference sailing off the wind.
Butch Ulmer: Woven Dacron will be the best value and most durable cloth for offshore sails. For offshore sailing, often with a small crew, sail handling will be an issue, so we recommend that cruisers stay away from heavily resined fabrics, which are harder to handle and more likely to tear than softer cloth that may not offer the peak of performance but will be easier to handle.
Bob Pattison: Dacron remains the best bang for the buck in a new cruising sail and there are a lot of options to consider. At Neil Pryde we have established standard coastal and offshore specs as a starting point. One thing to remember is that out there cruising, you are more likely to find someone who can repair Dacron than someone who can fix a laminated sail.
Laminated mainsails, such as this 3DL Marathon Sail, hold their shape better than Dacron sails. Modern laminates, sandwiched between layers of Dacron taffeta, will have lives of five years or more.What are some of the other options in sailcloth?
Steve Cruse: For those who want a higher performance sail, laminated sails will be the choice. North builds 3DL Marathon sails, which are molded and aramidfiber-reinforced laminates that are sandwiched inside layers of Dacron taffeta for durability and UV protection. These sound like high end sails, but they have proven to be practical for performance cruisers who want a top-of-the-line mainsail.
Robbie Doyle: If you are going to a laminated sail, I really like Vectran fibers. The fiber is a liquid crystal polymer that can be tricky to laminate but we have had good success with it. Vectran has pretty good UV resistance especially when the laminate is covered with Dacron taffeta. A high-quality Vectran laminated sail should give at least five years of good service. Another option for extended offshore sailing is Hydranet, which is tough and has good long-term shape retention.
Butch Ulmer: For those wanting a performance edge, there are a variety of upgrades from woven Dacron that will reduce stretch. We would upgrade first to UK's TapeDrive sails, which are very durable and offer good performance. TapeDrive sails can be built with a range of options that will affect durability, stretch, weight and price. Then we would look at string laminate sails.
Bob Pattison: There are so many choices, that your options for building durable performance sails are wide open. For cruisers wanting to build a performance sail, they can go with high quality Dacron or move up to cruising laminates or even go with Kevlar-Mylar laminates. We often recommend Pentex laminated sails that have proven to be very durable with a useful year-round working life of five years or more.
On a slab reefed mainsail, what batten system do you recommend?
Steve Cruse: I like batten systems that are simple with few moving parts so the sail is easy to hoist and drop. We prefer flat fiberglass battens and high-quality slides and mast fittings. We offer both front- and rear-entry batten pockets. For sailors heading offshore, we recommend front loading pockets since they are more durable and reduce wear and bulk at the leech end of the batten.
Robbie Doyle: I like to use full-length battens for the top two or three battens that are supporting the leech of the sail. The bottom two or three can be partial length–about 40 percent of the chord–to save weight and cost in the sail. Also, UPS has an eight-foot restriction on packages, so we try to work within that limit.
Doyle developed Nylatron donuts for reef clew fittings while building sails for Mirabella V.Butch Ulmer: If you don't have a big mainsail, you don't really need full battens. On bigger boats, over 40 feet or so, full battens with a Dutchman or another system make the sail much easier to handle. On full batten sails you need to go with a good low-friction mast track and slide. The STRONG Track system works well on boats up to 45 feet. Above that Antal and Harken and others make good systems.
Bob Pattison: We recommend slab reefing and like full-batten mainsails for cruising. Wear and tear is the biggest problem with mainsails. A full batten system acts as a kind of shock absorber that reduces flogging and luffing and will lengthen a sail's useful life.
What sort of sail controls, such as lazy jacks, do you recommend?
Steve Cruse: I am not a big fan of lazy jacks since they tend to catch on batten tips when you are raising the sail and you always have to handle them when you are putting on a sail cover or rigging an awning. North offers the QuickCover, which is a variation on lazy jacks and combines a detachable sail cover that can be removed if you are racing. I also like the Dutchman, which works well if it has been set up well.
Robbie Doyle: We developed the StackPack years ago and it still works well. The good thing about it is you can reef or furl the sail and it will always lie on top of the boom. We also like the Dutchman system, although building a sail cover to go around it can be a problem.
All the experts recommended two deep reefs instead of three shallow reefs to save weight and cost.Butch Ulmer: We have no particular preferences here. We'll lay out the options to the customers and let them decide which is best for them.
Bob Pattison: We build a lot of mainsails with lazy jacks/Lazy Bag combinations as well as Dutchman reefing systems. Both work well and are relatively simple to rig and maintain.
How many reef points do you recommend for a wide range of conditions?
Steve Cruse: First I like to keep the whole reefing system as simple as possible. That's why I don't usually recommend single-line reefing set ups. For coastal and offshore sailing, I suggest building in two deep reefs instead of three reefs. The third reef is rarely used and only adds weight and cost to the sail. I do like to see clew blocks at each reef, which makes hauling in the clew lines much easier. Harken Air blocks work well.
Robbie Doyle: I prefer using two deep reefs instead of three shallower reefs because you save both weight aloft and cost. When we were building the sails for Mirabella V, we developed Nylatron donut fittings that are sewn to the leech instead of building in cringles. The sail keeps a better shape and the reefing lines run easily through the donuts. For those sailing well offshore, a storm trysail is a safety net if you damage your primary sail.
Butch Ulmer: For coastal sailors we often recommend building in only one reef point, since most coastal sailors avoid strong wind and will stay inshore. For offshore sailors we recommend two deep reefs. And, we recommend carrying a storm trysail that can be rigged on its own track and hoisted easily. A trysail is really part of the boat's safety pack.
Bob Pattison: I always recommend two deep reefs in a sail instead of three. A third reef adds weight, chafe problems and cost to a sail and is seldom used. If you are heading offshore, we will always recommend a trysail and we suggest that an extra track for it be attached to the mast so the sail can be left hanked on and ready to go. The Offshore Racing Council publishes recommended sizes for trysails but we like to build them smaller, about 75 percent of the ORC sizes.
For in-mast furling mainsails, what batten system do you recommend?
Steve Cruse: Vertical battens are the way to go since they can be rolled right into the mast and around the mandrel. We have worked hard to make the batten pockets as unobtrusive as possible. We build the pockets so flat battens slide in from the bottom. This reduces cloth at the leech, which can bulk up or jam when the sail is reefed and furled.
Robbie Doyle: We developed the horizontal SwingBatten system for in-mast mains but only recommend it for racers who need as much performance as possible. For most sailors, vertical battens will give you a bit more roach and more sailing power.
Butch Ulmer: There has been some interest in full-length vertical battens but we do not recommend them. Instead we like short vertical battens that support some roach in the sail. We like to position the battens so the lower ends overlap the batten below it a bit. The battens have to be parallel to the mast so the sail will reef and furl easily.
Bob Pattison: An in-mast furling mainsail loses about 20 percent of the potential sail area. With vertical battens you can gain back about half of that sail area, and that will make your boat sail better and point higher. The system we developed for Beneteau USA's in-mast furling mainsails has proven to be durable and effective.
How can you further optimize the performance of a new in-mast furling mainsail?
Steve Cruse: By building the sail of a higher performance laminate, we have found the sail has a better shape and reefs and furls more easily than Dacron. We also recommend coating the sail with SailKote, which retards incidences of mildew and makes the sail slippery so it rolls and unrolls more easily.
Robbie Doyle: Since you can't adjust mast bend, you really need a high quality sail to add any performance. This is a good use for Vectran laminated sails since they will have better sail shape. Also, inlaid fiber sails, like the Vectran laminates, will roll better because they are flatter and smoother than Dacron.
Butch Ulmer: There is not much you can do beyond vertical battens to improve performance. But you can improve longevity by adding small patches to the leech that strengthen the sail at the points of loading at various reefing depths. And you can strengthen the leech since it gets extra loading from the vang and mainsheet.
Bob Pattison: Building a good sail will be half the battle but the sail will be flat since it must roll inside the mast. To adjust sail shape all you have is the outhaul and the halyard. The outhaul can really affect the lower two-thirds of the sail and add or reduce power. The main halyard will often be set up at the start of the season and forgotten. But, by easing or increasing halyard tension, you can add or decrease the draft in the sail. The main halyard should be checked regularly anyway. The main halyard should always be tight before furling to ensure proper furling, so if you have eased it some, take it back up before your roll the sail away.
For in-boom furling sails, how can you make the new sail as trouble free as possible?
Steve Cruse: This is a hot topic and we have seen the in-boom furling systems improve a lot over the years. For those interested in performance, in-boom systems allow us to build really nice full-battened sails. The sailmaking for these systems is very important. I would say 98 percent of new larger cruising boats have in-boom systems. Nearly 100 percent of the sails we build for these systems are laminates that stretch less than Dacron. That keeps the sail's dimensions in place and makes reefing and furling easier.
Robbie Doyle: This is another good use for in-laid fiber sails that are flat and smooth and hold their shapes well. For battens, we like to use S-glass and carbon laminates since they are lighter and stiffer than fiberglass battens
Butch Ulmer: It is critical for the sailmaker to follow the boom manufacturer's instructions very carefully, and they all vary. The tack angle and batten angles are critical. If the sail and battens don't roll into the boom perfectly parallel to the boom, the sail can jam or tear.
Bob Pattison: We do a lot of in-boom mainsails and have seen the boom makers really get the kinks out of their systems. Two key points make in-boom systems trouble free. First, it is imperative for the sailmaker to follow the manufacturer's specs carefully. If the batten angles are off, the system won't reef or furl. Second, UV protection is often ignored. The boom has to have an effective cover over the slot and the head of the sail, which is often left slightly hoisted. If this is the case, it needs acrylic patches just like the leech and foot of a roller genoa for protection. An in-boom system and mainsail are substantial investments and should be protected.
TOMORROW: The Experts on Headsails
A version of this story originally appeared in Blue Water Sailing magazine.