Sailing Downwind


Downwind Groove

by Steven Jung

I've been sailing (and racing) for some 16 years and you know what…. I learn something new every time I go sailing. I suspect that this trend will never end.

From a racing prospective, I think that downwind sailing is what separates the men from the boys. In other words, downwind sailing is the toughest point of sail compared with any other point of sail. What's the trick? It's the combination of doing the right things with the following adjustments given the existing conditions.

1) Sail Trim

The theory for setting up your sail trim applies equally for both the main and jib but I'm going to concentrate on setting up the main at this time.

The key for setting up your sail is to create the proper amount of "twist" in your sail. Here's what I mean. First, sheet your sail in tight as if you were sailing upwind. The entire sail from the top to bottom is pretty much parallel to your hulls. Now, ease your sail and look at it closely from top to bottom. You'll notice that the top falls away from parallel much quicker that the bottom of your sail. Continue easing until the sail comes in contact with your shrouds. The top half is pretty much perpendicular to your hulls while your boom is only about 45 degrees. This is the twist which you want to control with your mainsheet..

The following rough guidelines for setting up sail trim applies only to downwind point of sail described in the "Steering" section 3 described below.

For moderate wind, (a) set the traveler just beyond your hiking strap and (b) ease your mainsheet so that the space between your boom and rear crossbar is about 2 feet. I use 3 telltales on my main - one (1) on the second panel from the top about a foot from the luff, one (1) on the trailing edge of the sail one panel down from the first telltale, and one (1) on the same panel as the numbers about a foot in front of the trailing edge of the sail. There is no exact science for trimming the sheets when sailing downwind but try to get all three of those telltales to flow. If there's one telltale which is most important to keep flowing, I think that it's the one on the trailing edge. That's when you know that you've got the proper amount of twist in your sail.

When you have found what you think is the proper shape of your sail for downwind sailing, memorize it - for it's the same shape whether it's light, medium, or heavy wind. The difference is main sheet tension because of the different wind strength on the sail. In light winds, you can literally let out all your mainsheet to properly trim your sail. In heavy winds, I would bring your traveler inside your hiking straps and bring your mainsheet in so that your boom is less than 2 feet from the rear crossbar. Believe it or not, your sail will have the same basic shape despite the difference in sail trim just because of different wind strengths.

2) Crew Position

The basic rule for downwind sailing is to keep your weight forward. If you hear a gurgle coming from the stern of your boat, then you're probably too far back. Besides keeping your weight forward you should always try to keep your weight close together (as opposed to opposite corners of the trampoline). As the wind strength increases you can move your weight back. You will know when to move back when your bows start to get buried in the odd wave.

The exception to this rule is when you are doing the "wild thing". That's when you purposely fly a hull while sailing downwind. The crew positions themselves leeward of the centerline of the boat and halfway back and the skipper positions themselves pretty much at the rear beam at the centerline. You can do the wild thing only when wind strength is adequate to fly the hull which is approximately 12 - 15 knots and up.

3) Steering

The first thing that you do when setting up your boat is to putting a wind indicator or cassette tape on your bridle wires. Look around at the other boats and you'll get a good idea of what works best.

The optimum point of sail for Hobies when sailing downwind is 90 degrees apparent. Without getting into the physics of this, it's when your wind indicator is 90 degrees to the hulls while under sail. At this point of sail, you are NOT sailing directly downwind. Just as you beat (close hauled) back and forth when sailing upwind you sail downwind back and forth roughly 45 degrees to the true wind.

Here's the difference between upwind and downwind. It's just the opposite of sailing upwind because your apparent wind is the most significant factor. When a puff hits when sailing downwind, you will accelerate if your sails already properly trimmed. When you accelerate, your apparent wind will move forward and so you either steer further downwind or sheet in to correct your heading to 90 degrees apparent. In most conditions, you steer further downwind. If done properly you will feel the boat accelerate. Generally, don't sail below a 90 degrees apparent wind. Likewise, when in a lull, your boatspeed slows down and your apparent wind moves back so you head up to correct your sail heading. You steer an "S" pattern just like upwind. Try to anticipate the puffs and lulls so that you make your steering adjustments before you slow down. Only when you get a humungus puff in which you swear will cause a pitchpole do you bail out by heading up and sheeting out. Never let go of the main sheet.

Here's a tip that I learned from Paul Hess a few years ago. He was competing with Curt Christensen and he yelled out to Curt "How do you sail downwind so fast?" Curt's response was not a word but raised both hands in the air. Either he didn't know or he meant to put his hands in the air. Whenever possible, let the boat steer by itself - literally let go of the tiller. The fastest point of sail is the course of least resistance - in the puffs and lulls. If you need to head up or head down, do it smoothly without any jerky motions on your tiller.

I hope this helps and remember it's the "feel".

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