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Sails: The basic package

Apr 26, 2010

I have spent many an evening at potluck deck parties discussing the myriad options voyagers consider when selecting the right suit of sails for an offshore sailing vessel: space-age polymers, carbon fiber, construction techniques, aerodynamics, sailmaker warranties and the list goes on.

Even if differences of opinion cause a few sparks to fly, at some point we invariably agree on the same list of requirements for our vessel’s wardrobe.

When we make the transition from club racers and coastal sailors to hardcore offshore passagemakers, our vessel undergoes a parallel metamorphosis into a nearly bullet-proof bastion. We like to think our voyaging boats can sail or safely heave-to in anything short of a hurricane — and many sailing yachts can endure even this torment.

Both the mainsail and the jib, usually in the form of a roller furling genoa, should be relatively new, built of highly durable material, and capable of being repaired offshore. In addition, each of these two sails should be backed up by a spare.

Another must is a storm sail in the form of either a storm jib or a trysail. If you use it only once during a full circumnavigation, as I did in a horrific wind storm in the northern Red Sea, it will have paid for itself several times over.

Light-air sails, such as drifters, bloopers, spinnakers, cruising chutes and asymmetricals, are in a different class of gear and are beyond the scope of this discussion. Suffice to say, though, that carrying an easily deployed and doused light-air sail, my preference being a three-quarter-ounce Dacron drifter, is a useful if not necessary item to include in the sail inventory.


Mainsail design
At the outset of the design phase, you and your sailmaker are sitting before a large computer screen in the loft office studying a CAD/CAM rendering of a stock mainsail for your humble yacht. Generally speaking, at this point the overall shape and size of your mainsail is pretty much a given. But before the loft crew begins laying out the fabric for cutting, you may want to play with some variables. For starters, do you want to reduce the hoist of the main to lessen sail area or to accommodate a modification in the deck or rigging layout?

When my first mate Marilu and I were in Fiji, local sailmaker Allen Marshall cut the head of our main down a foot and added a full batten near the top in order to accommodate the high dodger he built for us. This resulted in very little reduction in sail area and zero whacks in the head from the boom.

Some cruisers order their mainsails cut to the first reef, a strategy offering several advantages. First, when it is time for the initial reef, it is already done. Second, the sail retains its aerodynamic integrity at the foot, or first reef, because there are no wrinkles in the sail. And third, with a lower mainsail head, there is less weight aloft.

Other voyagers point out the unrecoverable power loss in a permanently shortened main. For heavy displacement hulls, this is a valid argument. Our old Cal 30 Saltaire is a bit on the light side, so we rarely have a full main up while sailing offshore. The reduced sail area almost always guarantees more stability and greater speed, except when sailing to weather in an apparent wind of less than 12 knots — which means almost never.

The standard default cut for a mainsail is a cross-cut design, in which the panel seams are perpendicular to the leech. This is fast and easy to build, has fewer stitches than other designs, and is easier to repair than other cuts.

We usually associate biradial and triradial mains with racing yachts, but we’ve seen them cropping up here and there on voyaging vessels, too. In a triradial sail, the panel seams extend from the head, tack and clew and join in the middle of the sail, yielding less stretch and higher performance.

Various cloth weights are combined in radial construction to ensure strength where it is most needed while controlling the overall weight and shape of the sail. Radials are more expensive than cross-cuts, perhaps prohibitively so for the cost-conscious voyager. However, they are a great option for in-mast roller mainsails.

An obvious downside of radial sails is the many seams that may require repair. For the self-sufficient sailor, that could mean sitting atop the cabin roof in a six-foot swell working to mend the sail to put it back into service.

Have you thought of exchanging your traditional mainsail for a fully battened main? Modern yachts with high aspect rigs — that is, a relatively tall mast with a short boom — can benefit from the longer sail life, greater sail area and airplane wing-like performance offered by battens spanning from luff to leech.

A fully battened main is also easier to reef and keeps its shape, no matter how deeply reefed. If you are planning to install this type of design, plan on installing a lazy jack system to make lighter work of reefing and dousing the mainsail.

Does your main still have an old-fashioned rope foot? Consider changing to a main with a modern, sleek, aerodynamically superior loose foot. A loose foot will require laying out a few bucks for extra hardware on the boom to keep the sail adjusted properly, but the advantages will make it worthwhile.


Genoa design
You and your sailmaker alone are the best ones to determine the appropriate dimensions of your cruising genoa, as well as the rest of your canvas arsenal. Headsail design will vary depending on the type of rig (masthead, fractional or cutter), the overall size desired, and how high the clew will be set.

Calculating headsail area is slightly more complicated than for mainsails. In lieu of a fancy equation, try the following method. Think of the jib as two conjoined triangles, each of which is half of a rectangle. The adjoining line between the two imaginary rectangles is the LP, or luff perpendicular, which runs at a right angle from the luff to the clew. Multiply the length and width of each rectangle, divide each by two, add them up and you have the area of the jib, minus the curved drop at the foot.

Mike Taylor of T/A Sails in Wilmington, Calif., says crews of sailing yachts with lengths more than 50 feet LOA can benefit from lighter headsails and sometimes mainsails if they are built of laminate rather than Dacron. The lighter weight allows for a radial design, which would be rendered too heavy with extra stitching if made from Dacron.

Roller furling systems for headsails are all but a given on the modern voyaging yacht, although we have run into a few sailors in the South Pacific who still use hank-on sails and do not mind crawling out onto a wildly pitching foredeck at 0200 in the middle of a squall to change to a storm jib, and then an hour later to switch back to a working jib.

I prefer giving the roller furler a few turns behind the safety of the dodger and then crawling back into bed. But when it really starts honking out there, nothing beats the security of having a dedicated storm sail ready to deploy at a moment’s notice.


Storm sails
The question is not whether to pack a storm sail for your ocean crossing, but what kind to select: a trysail, a storm jib or both. Avoid lulling yourself into thinking a deep-reefed main or genny will do the trick. Even if either sail manages not to shred itself into a feather duster while hove-to many hours or days in 60 screaming knots of merciless fury, you may shorten that sail’s life by many thousands of miles of useful life.

Storm jib designs have evolved from headsails blossoming at the upper end into large genoas. Trysails are quite a different animal, though. While they can sail off the wind with some degree of efficiency, they are used primarily for heaving-to. Oddly, unlike the rest of the sail inventory, a trysail is generally not included in the nautical architect’s design plan for the vessel.

While Marilu and I were waiting out the cyclone season in Mooloolaba Harbour of Queensland, Australia, we commissioned a new storm trysail of 10-ounce Dacron. The sailmaker and I didn’t have a sail design to refer to, so I stood at dockside with a glass of Shiraz in my left hand, wagged my right index finger at a point just a tad above the spreaders and pronounced, “There.”

Then I nonchalantly waved my wine glass at a point slightly forward of a cleat along the cockpit coaming and uttered something like, “Yeah, that looks good.” Thus was born our trysail design, which later kept Saltaire hove-to perfectly and then propelled her downwind during a violent windstorm in the northern Red Sea.



Sailcloth
“The heart of a boat is its sails,” explains Taylor, “and the heart of a sail isn’t the cut. It’s the type and quality of cloth you use.”

The rule for voyaging yachts is fairly simple. For yachts measuring less than 50 feet on deck, Dacron is still the best cloth to use for both main and genny. We can argue about weight, but many experienced voyagers err on the heavy side. If your genoa is too heavy for light airs, then furl it up and put up a light-air sail. I insisted on 8-ounce cloth when we had the genoa built in Fiji, and I have never regretted that decision.

Challenge High Modulus sailcloth, which has a silky smooth feel, is a proven all-around material for building durable mainsails and headsails. It lends itself best to cross-cut designs for low-aspect sails due to its relatively equal strength along the cloth’s warp and fill yarns.

Modern high aspect mainsails are best produced of high-aspect cloth, in which the stress-bearing fill yarns are more numerable and densely packed than the warps. For these long, narrow sails, Challenge High Aspect cloth is one of the most preferred products.

The question of crossing over to a high-tech laminate on a cruising vessel is a matter of size. Taylor explains, “Typically, the loads on a 40-footer do not justify the expense of an exotic laminate.”

On a larger yacht, though, simply because of the sheer weight of the sail, Dacron can be very difficult to handle, especially while reefing during a gale. “A 6-ounce laminate sail will give you the strength of an 8-ounce sail while making it much easier to handle,” said Taylor.   

A biradial or triradial design often renders a sail susceptible to uneven stretch when working with traditional cloth. “If you want a radial-cut sail,” Taylor added, “I would recommend a cruising laminate rather than Dacron because of the differential stretch on the triangular bias.”

The main difference between racing and cruising laminates is the taffeta used to reduce stretch and give the sail more durability. Cruising laminates can contain either carbon fiber or Spectra to ensure the strength we seek in our sails.

North Sails uses its own in-house-designed cloth and laminates to produce its race-winning designs. North’s Spectra/Dyneema Gatorback styles, which include carbon yarns for greater strength and longevity, are designed for long periods of heavy weather at sea, rendering the sails a favorable option for cruising yachts.

North’s Spectra/Dyneema sails are produced as radial designs. This tight, light construction yields easier handling of sails on larger yachts along with world-class high performance, the kind that brings home trophies.


Construction
Once you and your sailmaker have agreed on a specific design and fabric for your new sail, you will want to insist on certain construction details, hardware and accoutrements. Until recently, the typical voyaging sail had three rows of zig-zag stitching with white UV-resistant thread along all seams. The alternative was to go with two stitches and to leave the center space open so that a future repair stitch could bite into cloth hitherto untouched by a sewing needle.

Most sailmakers now use machines capable of a zig-zag triple stitch, which means every zig and zag is comprised of three tiny stitches, adding a huge amount of holding power to the seam. This type of stitch is also wider than a standard triple stitch, so two rows of stitches is generally the rule.

And by the way, sail thread does not have to be white. It is available in a variety of colors from Bainbridge, but the color with the most UV resistance, as we all know, is blue. I am far more concerned with the durability of my sails than with coordinating their seam stitches with my cabin curtains.

All three corners of the sail, plus reef points and cunningham on the mainsail, must be reinforced with enough layers of cloth patches to ensure adequate strength and chafe resistance. Chafe patches will protect those points on the genoa coming in constant contact with the spreaders and deck stanchions. And leather chafe guards at all three corners will shield the cloth underneath from disintegrating due to excessive banging and rubbing.

Some racers and voyagers still insist on having the rings for the corner cringles hand sewn for enhanced strength. For us plebes, though, the industry standard for cruising sails is pressed stainless steel rings. Long web straps at each cringle spread the loads at those critical points, further reducing the potential for ripping along the line where they hinge and flap.

Saltaire’s mainsail has logged more than 30,000 nautical miles of sailing in all kinds of weather, and the sail’s pressed stainless cringles and web straps are still as good as new.

No doubt you have learned through experience that the primary load points on a sail are at the head and along the leech. The head will distribute its holding more evenly across the sail and resist fraying far better if it is sandwiched between anodized aluminum plates rather than if finished with a cringle.

You may want to add an extra layer of cloth along the entire length of the leech on both sails to further strengthen and stiffen that exposed, fragile area. While you’re at it, demand that the leech line, plus the foot line of the genoa, be of either double-braided Dacron, often sold as flag halyard, or even better, Spectra for its higher tensile strength.

While under sail, don’t make the mistake of forgetting to tighten the leech lines and the genoa foot line and secure them in their jam cleats to eliminate flapping. We do this every time we take in or shake out a reef in the mainsail, since each reef point has, or should have, its own jam or cam cleat.

Most of us take telltales for granted on the genoa, yet we study the mainsail’s belly and the flapping of the leech to guide us in determining the best trim of that sail. Ask your sailmaker to add a telltale to the trailing edge of each batten pocket to help you make finer adjustments in mainsail trim.


Reparability
Not to belabor the point, but simply constructed, easily repaired sails are part and parcel of the feeling of independence we draw from offshore voyaging. And to believe our sails will always look and perform like new is pure folly.

That’s why we have handy a set of canvas needles, a spool of waxed nylon thread and a palm aid in the event one of our sails incurs a rip or perhaps a hole from beating against the dodger after one of the reefing lines wiggles itself loose during a storm.

And that’s why, on the opening day of the Baja Ha-Ha, the horizon south of Point Loma, Calif., is lined with a bunting of white Dacron polyester sails. Those folks are going places, and they need to know they can cover a deep slice in the main with a large rectangle of cloth cut from a roll they keep in a lazaret, or replace a reef line grommet with a kit they keep in a tool box — while under sail.

A piece of paper with a warranty written on it does us zero good during a gale in the middle of the Indian Ocean. Our best insurance against disaster is having the best sails we can afford and the means to keep them in serviceable order, come what may.


Circumnavigator Bill Morris and his wife Marilu sailed across the Pacific and up the Great Barrier Reef aboard their Cal 30 Saltaire, learning lessons about food storage and preparation. Bill is the author of The Windvane Self-Steering Handbook.

Calculating the area of a mainsail
Sailmakers use several different formulas to calculate mainsail area, all of which are close approximations at best. The formula below is the easiest to follow:
P = luff
E = foot
In-mast roller mainsail:
P x E x 0.50 = sail area
Standard mainsail: P x E x 0.56 = sail area
Fully battened mainsail: P x E x 0.60 = sail area
Typical catamaran mainsail: P x E x 0.66 = sail area

For a main with a hoist of 50 feet and a foot of 15 feet, a fully battened mainsail yields an extra 30 square feet of sail area compared to a standard mainsail cut. The extra area extends the roach, or the curve of the leech, adding more power to your sail rig.
Bill Morris

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