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 Post subject: Rudder popping up....
PostPosted: Sun Jul 06, 2014 6:38 pm 
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Location: Nepean S.C. Ottawa, Canada
Laura and I stayed in to watch Djokovic claim his Wimbledon title. Some of the greatest tennis I've seen in years.
Both he and Federer brought their 'A' game. Time for some real sport - sailing !

It was warm this afternoon, sunny, 26C, winds WSW 14 - 17 knots, gusting up to 25, 1/8 cloud, and we're off....
For the first mile or so, I was pinching like crazy, getting used to the gusts. Then I settled on 14" of traveler,
cracked off about 15 degrees, and we beat upriver for nearly four miles. My buddy on his NACRA 500 screamed past us,
heading back to the Club in a cloud of spray, and I cursed myself for leaving the trap harness on shore. Oh well, we have wings.
We tacked, locked the traveler at 20", and set a course of about 120 degrees true, and started to run. We picked up speed, holding 20 mph without trouble. This was fun sailing!

Then a rudder popped up.... Yikes.... I managed to turn the SX18 into the wind, we locked the rudder down, and zoomed off once more. It happened again, this time to both rudders, so I decided to let out another 6" of traveler. That seemed to solve the problem.

No, the water is deep here, and its freshwater, so there is no kelp. The only thing I can figure is that the 'sideways' pressure on the rudders was huge. Is this a traveler adjustment thing, or do I tighten up the delrin screws?

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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: Mon Jul 07, 2014 12:51 am 
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Location: Bowie, MD
First step is to try tightening the delrin screw. You can get to the point where the delrin screw is so tight that the plastic rudder cam will not pop "up" when you raise the rudder arms/rudders, it will stay locked in the down position. I have never been able to get my rudder tension to work properly for high speed sailing. Either it is too light to hold the rudders locked at high speed, or it is too tight and the cams won't release. I have resorted to tightening the delrin screw as far as I can and still have the cam release and using bungee cords around the rudders (idea stolen from SRM) to hold the rudders down. I am thinking about trying to re-drill my rudders to see if a better hole geometry solves the problem.

Jim


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PostPosted: Mon Jul 07, 2014 5:22 am 
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Thanks Jim, that's what we'll do.
Expect more 'speed reports' in due course.

If our son had been with us, I might have flown the kite... there's always next time.

cheers

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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: Mon Jul 07, 2014 7:23 am 
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Location: Jersey Shore
No kelp in fresh water?? The fresh water lake we used to sail at often had ton's of kelp/weeds in the summer time.

Anyway, it is also possible that you don't have the slider plate in the upper casting adjusted properly. If the slider is too far forward for your rudder rake setting, it won't allow the cam to fully lock down (i.e., the cam will rotate and may hold lightly, but won't be fully engaged in the plunger). Just another thing to consider.

Otherwise tighten up the cam tension screw. And yes, I am a pretty strong believer in bungee cords to help hold the rudders down.

sm


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PostPosted: Mon Jul 07, 2014 9:28 am 
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srm, i just went through this process - and think I finally have it figured out: it was the slider plate that had fallen out of adjustment. Perfect now at high speed. Just out of curiosity - what is the bungee cord trick you refer to for holding the rudders down?

Thanks,
Jim


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PostPosted: Mon Jul 07, 2014 11:42 am 
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Location: Jersey Shore
You take a piece of 1/4" bungee and wrap it around the rudder and rudder pin to help hold the rudder down. Murrays sells washers/guides that bolt onto the outside if the lower casting to help hold the bungee in position. I also use a plastic hook on one end of the bungee so i can disconnect it when not sailing so the bungee lasts longer.

sm


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PostPosted: Thu Jul 10, 2014 6:11 am 
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Location: Nepean S.C. Ottawa, Canada
Before last night's club racing, tightened up the Delrin's a bunch, which was good.
WSW wind 9 knots gusting 16, sunny, 21C, and my son and I sailed the best we've ever sailed.
The T's beat us, but only by about 150 yards, so yes, I'll kill them on handicap.
Can't wait until next week.

Thanks for the advice. I checked, the plates are all the way forward.

Only once, in a gust, running under spin at well over 25 mph, did one rudder pop up, which we quickly locked down.

On the second downwind run, we were hit by a gust under spin, and took water up to the front cross bar.
Released the spin sheet, turned downwind, and we carried on without a problem.
Wow, the H18 has huge volumes in the front of the hulls, what a sweet ride!

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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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