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Optimizing Your Downwind Performance

This article was originally published on SailNet in August, 2000.

An asymmetrical cruising chute can be a cruising boat's best friend when the wind is aft of the beam.
Trade-wind sailing. Three simple words that have the power to conjure images of beautiful boats with billowing sails bound for exotic tropical destinations. Who hasn't dreamed of a trade-wind passage? You know how it goes, a warm quartering breeze, sails drawing nicely, and a starry dome overhead. You're at the helm of a stout cruising ketch, the boat occasionally surfing down a gentle ocean comber, the miles rolling under your keel day after day. This is the stock fantasy that convinces otherwise sane people to sell the house, buy a boat, and set off for far away places with names that are hard to pronounce.

Fortunately for those that sell boats and dreams, the two are interchangeable: the image of trade-wind sailing usually doesn't include the harsh clanking and worrisome banging as booms and running gear slam from side to side and headsails collapse and fill with sudden violence. The image also doesn't include pictures of the crew clutching anything permanent as the boat rolls from gunwale to gunwale, all the while cups, plates, dividers, binoculars, laptop computers, even the plastic flowers that were once velcroed in place slide back and forth across the cabin sole in a cacophonous trade-wind symphony. Ah yes, downwind sailing is not always what it is cracked up to be.

Let’s be fair, it really isn't the trade winds that are to blame; the problem is that few cruising boats are designed or set up for efficient downwind ocean sailing, especially when the trades are on the light side of moderate—10 knots. Downwind sailing at sea is always a challenge. Even on a peaceful night the ocean is alive, haunted with restless motion.

I was recently in Antigua, chatting with two professional skippers at the Pub in Neslon's Dockyard. They had both delivered fairly large boats across the Atlantic this winter, following the classic route from the Canary Islands to Barbados. When I mentioned what a nice trade-wind ride that is, both moaned and mentioned that the trades were a bit lighter than usual. "How did you keep the boat moving?" I asked.

"Well mate," said one of the skippers in an unmistakable South African accent, "we used that time-honored trick of turning on the engine.

Besides," he added somewhat embarrassed, "it was the only way to keep the bloody boat from rolling. What with the solar panel arch, wind generator pole, and radar, we’re so damned top heavy."

The additional speed that would almost certainly be derived from a cruising kite could help this vessel make its destination before the weather turns foul.
Motoring downwind is more common than it should be, why? First, in many ways the nature of cruising has changed; we're all on a schedule of some sort, and keeping up the daily dosage of miles is part of the passaging equation. Secondly, an amazingly large number of boats are simply not prepared for downwind work, and the situation is compounded in light air because so many cruising boats are overloaded with the latest equipment. When the wind is light, motoring is often the only downwind option. Let's look at some alternatives to internal combustion for keeping your boat moving in light to moderate trade-wind conditions.

The first consideration is to design a downwind system specifically for your rig. Cutter rigs and furling headsails are found on many cruising boats these days, and while they're efficient for across the wind sailing, they are not very effective when broad reaching or running. A cutter rig requires that the jib, or headsail, be rather high cut, and a yankee style jib that combines with the staysail to fill the fore triangle usually sets best. However, when you ease farther off the wind, it is difficult to satisfy the sails. The main blankets the staysail, the yankee—which is also blanketed by the staysail—is too small to fill easily, and the clew is often too high to pole out efficiently. A simple solution would be changing headsails. However, the truth is, most cruisers resist changing furling headsails underway. It just isn't as easy as it looks, especially for a cruising couple since a third pair of hands would really help guide the luff up the foils of the furler. Few cruisers, myself included, relish the prospect of rounding up to douse and hoist a new sail. Even in moderate trade wind conditions this is often a wet task. The result is that most boats tack downwind at angles that add a lot of miles to the course. A better idea is to use a drifter or cruising spinnaker for downwind work when your primary headsails are roller furled.

Poling out a genoa or jib can be an effective method of gaining more downwind speed.
I used a drifter to literally pull me across the Atlantic a few years ago while delivering a 38-foot Jeanneau that had been set up as a cutter. The nylon drifter was slightly larger than a 150 percent genoa but at 1.5 ounces, much lighter and easier to fill. It had a wire luff and although it could have been set flying, it worked better when I improvised some parrel beads with nylon webbing and a crew member's juggling balls. (He magnanimously allowed me to drill holes through them.) The parrel beads wrapped around the rolled up headsail and back through the head shackle as the drifter was hoisted on the spinnaker halyard. When the going turned really light, I set the drifter to leeward, running the sheet through the end of the main boom which was secured in place with fore and aft preventers and acted like a pole. I then used the whisker pole to support the yankee on the opposite side. We ran like this for days, more or less wing and wing, managing to keep the boat moving at five plus knots. The rig was pretty well balanced, allowed the autopilot to steer, and kept the mainsail, which was lying peacefully on the boom from slamming about—we even rigged up a sun awning on the boom. Another advantage of this downwind rig is that when the wind pipes up a bit, it is easy to shorten sail by rolling in the yankee. It is important to set up a block on the boom end to keep the drifter sheet from chafing. It is also wise to prevent the whisker pole from moving fore and aft so that you can utilize the furling gear without worrying about the pole slamming forward.

Speaking of poles, most cruisers would be better served to carry a lighter whisker pole than a heavy-duty spinnaker pole. Unless you intend to fly broad-shouldered, symmetrical chutes, the weight and trouble of a spinnaker pole are unnecessary. On a recent delivery from the islands, I had to pole out the headsail of a Swan 44 with the massive stump of aluminum Swan provides for a spinnaker pole. It was an exhausting task hefting the pole into position even with the help of the topping lift, and also a dangerous one when it was time to drop it as the wind increased. A whisker pole, or as some call it, running pole, can be permanently mounted on the mast with a track, slide/car, pulleys, and a lift. My brother-in-law, Trevor Richards, who sailed single-handed around the world, swears that twin headsails, each set on a pole, are the most stress-free way to make miles in the trades. This system works best with twin forestays. Unfortunately, the stays need to be close together and the technique is not well suited for roller-furling systems, which induce forestay sag and need adequate spacing for the drums.

The best way to set a whisker pole while underway is to maintain course and roll in most of the headsail. This requires a bit of muscle because the sail will still be filled. Be sure that you maintain good control of the sheet. With the boat slowed down but still under control, use the pole lift to deploy the pole and run the sheet, which has little or no tension at this point through the outboard pole end. Use an after guy, or preventer, to keep the pole from running forward as you unroll the headsail. This preventer also allows sail to be shortened with the pole in place, although it usually needs to be repositioned afterward. Removing the pole is easy—just roll the headsail back in, relieving all sheet tension, release the preventer, and lower away.

This symmetrical spinnaker is the perfect sail for these spotty conditions, particularly since setting it on a tack pennant like the one above helps keep the kite out of the lee of the mainsail.
While I have used drifters with success, and veteran cruisers Lynn and Larry Pardey recommend them, I prefer a cruising spinnaker. Yes, even for offshore work, cruising spinnakers are just much more efficient than drifters or poled-out headsails. While cruising spinnakers have a variety of trade names, they are generically referred to as asymmetrical, which means that like other headsails they have a longer luff than leech. Typically they're about twice the area of a 150 percent genoa and around 25 percent less than a conventional chute. They are set without a pole, using a tack pennant usually run forward of the bow pulpit. Like a drifter, they can be set loose luffed, and often are; however, I prefer to keep the head close to the forestay. Maintaining control of your sails is vital when sailing offshore and by keeping the cruising spinnaker connected to the forestay it is not only less likely to cause trouble, but it also sets better.

There are three keys to keeping a cruising spinnaker in line when it is being used day after day. First, use parrel beads on the upper snap shackle allowing the sail to be hoisted over your furling headsail and a control line or fiberglass Tacker (made by ATN) to keep the lower part of the luff in line. Of course, you can't unfurl the headsail until the spinnaker has been doused or you'll send the beads scattering. Second, run the tack pennant, or downhaul, through a block that lets the sail fly forward of the stay—the farther forward, the better you can mount it. Thirdly, and most importantly, be on the lookout for chafe. Change the halyard tension frequently, if for no other reason than to eliminate chafe. Do the same thing with tack pennant and the sheets. Spinnakers exert a lot more sheer loading on the lines and cause chaff much faster than standard headsail loads.

On a lazy passage from the Canaries straight through to the Virgin Islands, the so-called 'ladies trades,' I once flew a cruising spinnaker 18 consecutive days and nights. By keeping the wind angle between 120 and 150 degrees, the little 33-foot Neptunian ketch made nice use of the 10 to 15-knot early summer trades. The only problems encountered were a chaffed spinnaker halyard and a small tear along the foot where the chute snagged one of the running lights on the pulpit at night. On a passage from Chile to San Francisco in a Contessa 32 sloop, we flew our cruising chute at every opportunity. Without it, I might still be sitting in the equatorial doldrums. While delivering an overweight Morgan 45 ketch across the Atlantic, the cruising spinnaker doubled as our therapist as we encountered day after day of light conditions. There are times when only two things will keep the boat moving, a spinnaker (even a cruising spinnaker) or an engine. For me it's an easy choice.

Suggested Reading:

Refining Your Downwind Sails by Brian Hancock

Using the Asymmetrical Spinnaker by Brian Hancock

AirForce Sails

John Kretschmer is offline  
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