Wave skills

Waves. They are our friend downwind and our enemy upwind. They add another layer of technical skills and it’s little wonder that waves separate the fleet very quickly.

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Anytime you are sailing far enough from shore, or in a seabreeze, we are exposed to waves. The size of the waves often determines the type of rig set-up. Although the Laser has a simple rig, we still have the ability to pull a particular shape into the sail.  For example, in flatter water, we may want a flattish sail that is set up for low drag and to control whatever the wind strength is. However, in choppy water, we want a sail that is more forgiving to changes in steering angles, but still has enough ‘torque’ to push through waves upwind. The sail will look (and feel) very different for 8 knots flat water compared to 8 knots choppy water. So here is a clue straight away…..ask yourself, are you setting the sail for flat water or for choppy water? Well now you have to have a definition of “choppy water”.

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 I think the definition of chop is when going upwind, that the waves either make you change direction (by slapping the bow away) or slowing you down (by slamming into the bow). Either of these situations is damaging to speed and height and we now have to steer more aggressively around the waves. But now the rig must accommodate this extra steering range. It must be broadened in its ability to be efficient both when (momentarily) high and low. How? Add more depth to the entry. That is Cunningham. Most people are reluctant to use this as we associate it with depowering on a windy day. This is true. So we need to apply just enough Cunningham to add entry depth, and no more. Similarly, we use soft vang to achieve the same result. A straighter mast also means a deeper entry so we make sure we are not too hard on the vang in winds less than say 12 knots.  With a softer vang, we now have full control of sail shape with mainsheet tension alone. It becomes very simple. In bigger waves, ease a touch of sheet. This straightens the mast, adds depth and power and relaxes the leech a little. Perfect for finding that extra punch in bigger waves on lighter wind days. As the wind strength increases, just add more and more downhaul and vang in equal portions.

 

Update: The new MarkII sail differs slightly. It has more power with firmer leeches.  The Cunningham does not change sail shape as much as it did with the MarkI. For the new cut sail, when you are over-powered, you have to rely on more vang and then ease/play sheet as the main too for power management. It makes the new sail slightly labour intensive and expect the arms to get as tired as the legs, especially on gusty/shifty days.

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© Brett Beyer