Skiron07
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I think you’ve got it right.  As the water becomes cold or more viscous it creates more drag and your ski moves through it more slowly.  To combat this effect you can decrease wing angle which decreases drag.ÂÂ
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I think the confusion comes from defining cold water as “fast†which would infer you should add wing angle to slow down the ski.  But fast in this context refers to the sensation or perception of the skier feels.  Because you are moving slower through the water it is easier to get narrow in the course, there is less time for the pre-turn or turn and as a result things “feel†fast.
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This analogy may not work for you, but when I’m skiing into the wind the combination of the wind speed and my speed give me the sensation that I’m traveling very fast when in fact the wind is actually slowing me down.