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Using the Asymmetrical Spinnaker

When the wind is abeam or abaft the beam, you can make some serious headway with the use of an asymmetrical spinnaker.
There is nothing quite like a day in the trades with a warm wind at your back and the open arms of the horizon ahead stretched in a wide arc waiting for you. Imagine romping downwind with every inch of sail set, your boat rollicking and reveling in the conditions while you hang on tight with a knot the size of a monkey fist in your gut. If you're like me, you maintain a love-hate relationship with sailing downwind—you're afraid that the boat will get out of control or something will go wrong, but you also prize the thrill of the ride, so you keep the sails set. Welcome to a place where all offshore sailors have been, the place between fear and fabulous sailing.

In my previous articles, I have discussed the working sails in your inventory, as well as the fabric and sail engineering that goes into making them. Now it's time to ease sheets, let the wind come aft, and set some offwind sails. It's time to learn what choices you have and how to overcome your fear (or at least trepidation) of spinnakers.

So what are your choices? Well, the answer depends upon your boat, the size of your crew, and how you like to sail. Are you a single-hander who likes to go fast? I am. Not too long ago I sailed across the Atlantic alone and managed to sleep while sailing with a big asymmetrical set. My instruments recorded a top speed of 15 knots while I dozed, oblivious to the spray flying. A few months later I sailed to the Caribbean and never set a spinnaker because the crew wasn't confident in their ability to get it down; or perhaps they were simply being prudent. Whatever your situation, there is an offwind sail suited for your boat.

Let's assume you are a cruising couple who have some blue-water experience, a well-found boat, and a yearn for additional performance. And let's say that your boat came with all the bits needed to set a spinnaker, but you are not sure if it's a good idea. My outlook is that if you're sailing during the day when you can see the weather coming your way, why not hoist a spinnaker? (At night, with cooling air and warm water, you're likely to get small localized squalls which can thump you when you least expect them, so for now let's concentrate on spinnaker sailing during the day, and set something a bit more conservative for the dark hours.)

The most popular spinnakers these days are asymmetrical in shape, and although they were developed for racing sailors, they have quickly become an integral part of cruising inventories. In many ways they are more suitable for sailing off the wind than a conventional symmetrical spinnaker. This is true not only because they are easier to set and douse, but because, except in those rare occasions where you are sailing dead downwind, the wind flows across the sail and the asymmetrical shape provides more drive. Only once the wind has come way aft does it start to flow down the sail, but until then the asymmetrical shape works best. On my recent trip from Spain to the Azores, the wind was dead astern for part of the trip, and when it was that far back I set the asymmetrical on the spinnaker pole and rotated it aft just as you would do with a regular symmetrical spinnaker.

Having an adjustable tack line on an asymmetrical—like that seen here—is a critical feature for performance. Essentially you ease it for deeper angles and tighten it when you're sailing closer to the wind.

Before we get ahead of ourselves let's discuss asymmetricals in more detail. As their name implies, they are asymmetrical in shape, meaning that they can only be set one way, like mainsails and headsails. The beauty of asymmetrical spinnakers is that you do not need a spinnaker pole and all the associated hardware and running rigging to fly these sails. An asymmetrical simply tacks either to a bowsprit if your boat has one, or to a fitting on the bow. The advantage of the sprit is that it allows the sail to be set away from the rest of the sail plan and out of its lee. It also allows you to have a slightly larger sail. You can set the sail on a regular spinnaker halyard and sheet it aft just as you would a conventional spinnaker, but it's a good idea to have an adjustable tack so that you can tighten the luff when close reaching, and ease it off to rotate the sail around when running (see sidebar).

Asymmetrical Variations    There are two kinds of asymmetrical spinnakers: the regular asymmetrical which covers the broadest wind range and is the most common, and the Asymmetrical Reaching Spinnaker, a sail designed and built for close-reaching. The ARS is cut with less shape and less sail area (it has the same hoist, but a narrower girth) than an conventional asymmetrical, and is more of a purpose-designed sail. It can be set and doused with either a spinnaker sock, or in some cases if the sail is flat enough, it can be set and doused using a roller-furling unit. If a furling unit is to be used, a strong, low stretch line is sewn in the luff of the sail so that it can be snugged up tight against the furling drum and masthead swivel. (These sails don't have foils like you'd find on a regular furling unit.) The ARS can be used from 50 degrees apparent wind angle AWA to about 110 degrees. A "regular" asymmetrical has a wind range of roughly 60 degrees AWA to around 145 degrees AWA, and is designed to be forgiving and easy to trim. Because of its asymmetrical shape and the wind flowing across the sail, it actually works much better than a conventional spinnaker set on a pole, except, as already pointed out, when the wind is way aft and the flow is down the sail. For the most part, either because you don't have the equipment or don't want to bother with a pole, you will need to sail higher wind angles to keep the sail full and pulling. This in turn will lead to more jibing, but the good news is that jibing is easy, especially if you have a spinnaker sock—you simply douse the sail with the sock, re-lead the sheet and tack lines, and reset the sail on the other side.

Using a spinnaker sock, like the one shown bunched up at the masthead here, makes setting and dousing an asymmetrical kite a piece of cake.

Spinnaker Socks    The spinnaker sock is one of the great sailhandling innovations that has evolved from the single-handed sailing arena. First developed to help single-handers set and douse their spinnakers, socks have since been refined and no cruising sailor should leave home without one. In my opinion, there's only one spinnaker sock product that always works perfectly—the ATN. The fabric used and the design of the hoop allows the system to work properly, but there are a few key points to note before using one. These points will make it easier and safer to set, and more importantly, to douse your sail.

If you've had no prior, or very little, experience with the spinnaker sock, I'd recommend experimenting with it on a calm day when the wind is light so that you can get used to it and its control lines. It is important to mark the tack line and the sheet with reference points so that when you are setting the spinnaker you are able to duplicate the position of the sail. In other words, before you hoist the sock and the spinnaker fills with air, you want to be sure that the tack line is tight enough and your sheet is set just about right. If the sheet is too loose the spinnaker will flap and might wrap around the forestay. If the sheet is too tight it will cause you to round up and possibly broach. Using a piece of tape and whipping twine mark your running rigging against a reference point on the boat such as where the sheet goes through the block or where it meets the winch.

The second most important thing you can do is run the sock control lines through a ratchet block that is fixed securely to your deck. With this arrangement, you will be pulling up from the deck when dousing the sail rather than pulling down, which might put you off balance and cause you to fall down. The ratchet block has two purposes. First, the ratchet makes it easier to control the line and secondly the noise of the ratchet will tell you which way the line is running through the block, and consequently, if you are pulling the line to douse the sail or the line to set it. This is particularly useful at night or when you have to douse in a hurry. Finally, always remember to use the dead air in the lee of your mainsail to your advantage. Have the person at the helm run off to a broad angle so that you can pull down the sock while the spinnaker is in the lee of the mainsail. You also might want to take note of the wind angle that works best so that the next time you need to drop the sail you have an additional reference point. Never try and get the sail down on a reach—it will flap out to leeward, making it impossible to douse. When the boat is on the proper wind angle to blanket the spinnaker behind the main, release the tack line and let the sail float toward the main where you will easily be able to snug it with the sock.

With a little patience and a little practice you will get the hang of asymmetrical spinnakers and spinnaker socks, and your enjoyment of sailing off the wind will increase dramatically. Instead of starting the engine and motoring home once the wind dies and comes aft, you will be able to glide effortlessly on a smooth sea providing a treat for yourself and those watching you.

Asymmetrical Accessories

There are several ways to fit an asymmetrical spinnaker to your boat. One arrangement I recommend is a device called The Tacker, which assembles around your headstay as a tack fitting, allowing the sail to be sheeted tightly up against the stay rather than a few feet to leeward. Having the sail sag off centerline limits its range and causes a lot of unnecessary leeway.

Another good feature is using a single, long spinnaker sheet that loops around the clew fitting by way of a cow hitch (or lark's head) so that you don't have to use knots, which might catch on the headstay when you jibe. 

Adding a sock to your asymmetrical will make it easy to hoist and douse, especially if you're shorthanded. I recommend those supplied by ATN. Both of the above products are available through the SailNet online Store.

Brian Hancock is offline  
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