This question relates to a Hobie 16 with the comp tip mast.
1. I have a 6:1 downhaul system installed on the mast. How much downhaul tension is required/recommended? I notice that with some effort, I can create quite a bend in the top of the mast.
Thanks
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Karl, Captain of Stayin' Thirsty
2011 Hobie 16SE
Atlanta, GA
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Downhaul on a Hobie 16
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- Rank: Mate
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Posted: Aug 08, 2011 - 10:42 AM
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- Rank: Lubber
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Posted: Aug 08, 2011 - 12:18 PM
The downhall (cunningham) relates to your sail shape. The more wind the more outhall and downhall you should put on. When cunningham is applied if flattens the sail and also creates a bit of backward mast bend. This allows air to spill off the sail essentially making you slower. So be carefull how much is applied. As a rule of thumb I apply enough cunningham to pull the wrinkles out of the sail, which disturb wind flow. In heavier winds, if the boat is heeling hard, instead of easing off the traveller or mainsheet, I would apply more downhall and outhall to allow wind to spill off the sail and keep the boat flatter. When you ease off of your mainsheet on a beat it affects the ability of your boat to point. I suggestion playing around with these adjustments in different wind conditions while looking at your sail shape and how they affect boat speed.
I hope this answers your question.
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Alex
Prindle 16 "Shake & Bake"
Portland, Oregon
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Posted: Aug 08, 2011 - 12:23 PM
There are many variables (wind, waves, boat/crew weight, etc.) that affect sheeting and downhaul, but the short version is 1) more wind calls for more downhaul to flatten and depower sail, and 2) you're mainly trying to get the wrinkles out.
Longer version.....Upwind, the downhaul is used in conjunction with main sheet to provide a nice, smooth sail surface appropriate for the conditions. Stronger wind calls for a flatter sail. You sheet harder, but that causes wrinkles that point aft and down toward the main blocks......add downhaul to further flatten sail and remove wrinkles. It is very normal for the Hobie 16 comp tip, in fact the whole mast, to be significantly bent for high winds (it's a good thing!). As the wind lightens and you reduce sheet tension, you will have wrinkles that point forward and down toward the down haul. Ease downhaul to remove. Down wind you generally want downhaul loose, but I'm not convinced there's a tremendous gain in doing so on the Hobie 16.
I highly recommend Rick White's book "Catamaran Racing for the 90s" for this and many other intermediate level boat tuning and handling issues.
Didn't I read where you're going to Juana's Good Time Regatta? If so, I'll see you there!
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Jerome Vaughan
Hobie 16
Clinton, Mississippi
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