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PostPosted: Thu Jun 21, 2012 2:30 pm 
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Joined: Mon Jul 04, 2005 10:13 am
Posts: 662
Location: Nepean S.C. Ottawa, Canada
Weds night racing, round the buoys...first two races were the usual....Tornado's were 1-2-3, and we lagged behind. By the third race, my son and I were 'dialed in', and I gave him the hot stick. A good start, a good line upwind, and off we went. At the downwind mark, Matt's crew slipped and fell off and I gave a whoop of joy....here was our chance to beat a Tornado!

Never fear, Matt came back, and over beers afterwards, we agreed my son did extremely well to come as close as we did. On corrected or handicap time, we won that race....

Then we talked some more...how tight or loose should the mast rotator be?
Most of the literature says that the tail of the rotator should be pointing towards the shroud. We actually run it tighter than that, and we may be losing some optimization. Mostly, we sail in light winds....thoughts?

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1989 Hobie SX18 Sail # 1947
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'


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PostPosted: Thu Jun 21, 2012 4:29 pm 
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John, you didn't indicate a point of sail. My notes say point at the shroud when sailing upwind in light, medium and heavy breeze. Downwind: 90 to 100 degrees in light to medium breeze and 70 to 80 degrees in heavier air. But then you're sailing with an entirely different rig, an SX mast with a custom flattop sail. I suspect your sweet spots are going to be different. Is your SX stick solid aluminum or does it have a comp-tip? What are you using as a Portsmouth number for that rig?


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PostPosted: Fri Jun 22, 2012 6:14 am 
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Joined: Mon Feb 09, 2004 10:08 pm
Posts: 139
Location: Ottawa, Canada
The mast rotator is the primary control for sail fullness. The mast is thinner sideways than front to back. So if you allow it to rotate more it will bend more under mainsheet pressure and the middle pushes forward and takes fullness out of the sail. Seems counterintuitive to allow the mast to rotate more to make the airfoil flatter, but there it is.

Upwind before the start look at your middle telltale, half way up, half way back, and move the rotator enough that you start to pick up the inside telltale. The mast will bend until it is limited by the diamond wire. Diamond wire tension, for a box stock 18, your mileage may vary, is crew weight dependant. With your palms on either side of the mast against the diamond wires, press inwards until they touch the mast. This should happen three feet above the diamond wire attachment point for minimum weight crews (295 pounds), two feet if you're 15 pounds over or so, one foot if you're ... gifted in this regard.

Downwind we used to just blow the adjuster off and worry about other things. You'd like the rotator to go forward of the front crossmember if it will go. I guess that's 100 degrees in the other response. Try full rotation with full traveller on the beach and tie a knot in the rotator adjuster line. If it goes far enough it can try and pry the gooseneck apart.

So ... recap ... set it for upwind on the day, blow it off downwind, have the crew reset it within a microcentimeter while pushing the boards down, resetting the outhaul, resetting the jib cars, sheeting in moving back, and hooking on.

Have a nice day.


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