SAIL DESIGN: The Art of Asymmetricals
By Richard Bouzaid, Head Sail Designer,
DOYLE SAILS
PART ONE
As sailors, what is it we look for in an asymmetrical spinnaker? While a racing program may look for some extra features, many of the same principles are desirable in both a racing and cruising asymmetrical. And although computing power has developed such that upwind sails can now be reasonable well simulated on desktop machines, downwind sails are far more difficult. Even with such useful tools as wind tunnels, taking a sail that tests well in a wind tunnel and turning that into a sail that will perform, not only in straight line speed but also be durable and be forgiving to trim in changing wind angles, is the challenge and art.

Materials have a big effect on downwind sails and due to the relatively low apparent wind speeds that the sails see compared to working sails can have a big effect on the life of the sail. Most spinnakers, asymmetricals included, are built from nylon-based fabrics. These materials are light and range from .5 oz through to 2.2 oz. While nylon-based materials are relatively stretchy, which allows them to flap and be taken in relatively high wind speeds, overloading these materials does cause them to become more porous and reduces their strength considerably. Most people will admit to being caught over range with a spinnaker up or in a big broach with the spinnaker flapping and the boat on its side. Most people will also be surprised that the sail didn't break at that time, and then some time later while sailing along in nice conditions the sail breaks for what seems to be no reason at all.

A good guide for wind strengths for different materials that will keep the sails out of the dangerous overloading range is below. Note that these are apparent wind speeds, not true wind speeds. Also, these wind speeds should be lowered if the sail is old or has been overloaded in the past.

• .5oz cloth 10 knots Apparent Wind Speed
• .75oz cloth 14 knots AWS
• 1.5oz cloth 18 knots AWS
• 2.2 oz cloth 21 knots AWS

Whilst nylon is a good material for asymmetrical spinnakers, other fabrics have more recently been developed for closer reaching designs that overcome the problem of the stretch and overloading of nylon. As the sails become smaller and flatter for sailing at closer angles, the yacht's stability has typically been the limiting factor and nylon sails have historically been strong enough. Now, with many of the more modern racing yachts with either water ballast or canting keels that have high stability and can carry reaching asymmetrical sails in much higher winds and at much higher boat speeds, alternative higher strength materials have been developed. Fabrics utilizing polyester and Spectra, Kevlar, and carbon fiber are common for high performance race yachts that carry only asymmetrical spinnakers. While these fabrics are considerably more expensive than nylon materials, they are much stronger and lower stretch.
CLICK HERE FOR COMPLETE INFO ON DOYLE ASYMMETRICALS
Coming in Art of the Asymmetrical, Part Two: From the Wind Tunnel to the Water

SPEED TIPS : Winning in a Beneteau 36.7...From the Bottom Up!
By Mark Ploch, DOYLE PLOCH SAILS
A winning campaign is always a product of preparation! With the Beneteau 36.7 that starts with the bottom. Be sure that all the through-hulls are faired into the hull to be as smooth as possible. The keel comes in pretty good condition from the factory, but it also will need some smoothing and sanding before it is truly race-ready. As always, some keels start off better than others, and on mine all I needed was a thick barrier coat and some good wet-sanding.

Now that the bottom is a smooth as possible with the orange peel in the bottom paint sanded out, it's time to look at the deck layout. It is very important to be able to control the sails and make changes to optimize the sail shapes for changing conditions. We took the main traveler purchase blocks off the traveler and moved them to the jib tracks--this increased the purchase on the jib car, and made a nicer place for main trimmer to sit! The main traveler controls were changes to bullet blocks bolted along side the traveler; I did not move the cleats to the side of the boat from the car, but I think if I step on the traveler line and uncleated one more time I would! The other important control to bring closer is the backstay. This should be led so that it can be easily adjusted by the main trimmer.

Sailing the Beneteau 36.7 fast is not as easy as you may think. It is very important to get up to full speed out of the tack as quickly as possible, and this usually means have the jib and main only trimmed to about 85%. Once you increase close to the target you can trim to 100% or whatever is appropriate for the wind and sea conditions to maintain your target speed. In very light air and lumpy water you rarely trim more than 85%-- I found very quickly that sailing above the target speed upwind is a NO-gainer! In fact, in smooth water the biggest gains are to sail pinched! Keeping the main with all telltales flowing is also very fast, a tight leech -- especially in big puffy breeze -- is very slow and hard to steer straight. Plenty of backstay, a flat main, and not too high up on the traveler is good. The genoa is not sheeted to a very close angle and therefore it is not so important to bring the main much over center.

We also keep our weight very packed together on the rail, with one person hiking in front of the shrouds. This crew location also works very well downwind -- until you get winds over 20 knots, when you'll want to slide aft! We did not change down to the #3 until the wind was a solid 18 knots. You can get by with the genoa in 20 knots of breeze, but it is very hard on the main. You will be just as fast and maybe higher if you go with the #3 and keep the main trimmed, instead of flogging, most of the time!
CLICK HERE FOR COMPLETE INFO ON SAILS AND TUNING FOR THE BENETEAU 36.7

SUPERYACHTS: Speed and Style Reign!
By Kristen Heissenbuttel, DOYLE SAILMAKERS
A little fog can't stop a superyacht! Three months after its southern counterpart in St. Barth's, a crowd of superyachts converged on Newport, RI, last July to race in the Newport Bucket. Similar to the St. Barth's bucket, this year's Newport Bucket saw a record number of entrants, ranging in size from the 168-foot Perini Navi Perseus to the 56-foot Tripp-designed Brigadoon. However, unlike the Caribbean event, Newport's "bucket" was not blessed with perpetual sunlight and breeze. But the weekend was still, "No worries, mon!" afloat and at the social events ashore.

Racing began on Saturday morning in a thick fog and a light breeze. Needless to say, the fog made racing interesting...the low visibility meant that one moment you felt alone on the racecourse and a minute later a 100-foot yacht suddenly emerged from the mist! Radar was essential and foghorns came in handy during close maneuvering, but the fleet remained upbeat. The fog continued on Sunday and, thanks to a good rating system, so did the close competition. The boats ranged widely not only in size but in speed, with Tree of Life, a classic 75-foot schooner, on one extreme and the speedy Wally 77 Carrera at the other end. However, the finishes remained close and competitive, with Avalon taking the Bucket for the weekend, followed by Whitehawk and Zingaro.

Doyle representatives in attendance included Robbie Doyle and Tyler Doyle, sailing on Rogue (a Trehard 98-footer powered by a DOYLE D4 Vectran/Carbon main and genoa); Glenn Cook and Richard Bouzaid on Symmetry (a Frers 96-footer with a DOYLE DVC Paneled Vectran/Carbon rollboom mainsail and DOYLE DVC roller-furling staysail and genoa); and Kristen Heissenbuttel and Peter Grimm on Perseus (a Perini Navi 164-footer soon to receive a full inventory (rollboom main/mizzen, genoa, staysail) of DOYLE DVC Paneled Vectran/Carbon sails. Other Doyle entrants included Anny, a Baltic 90, and Paraiso, a Fontaine/Alloy 108-footer with a DOYLE DVC Paneled Vectran/Carbon rollboom mainsail and DOYLE DVC roller-furling staysail and genoa. Thanks also to the project managers of Paraiso (MCM) and Symmetry (Doug Fredericks) who have helped Doyle create sail inventories worthy of these first-class superyachts!