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#33976 - 06/02/04 06:45 AM Up Wind rudder stall  
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jes9613 Offline
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Austin Lake MI
Hey Guys,
Last nights club races in 15 - 18 winds, I get a great start to find that I am sailing 5 degrees +/- lower than the rest of the competition. I feather up to match ( inland lake with short legs) and the boat justs stops, I can't bring it back as the rudders are turned at 45 degrees with no response (stalled)
I'm thinking that I may be raked too far back. Any thoughts?
John

-- Have You Seen This? --
#33977 - 06/02/04 03:11 PM Re: Up Wind rudder stall [Re: jes9613]  
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Fritz Offline
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Flensburg, Germany
John,
most of the time it is the rudder itself.
Rudders on a Hobie 16 must be extremely stiff to prevent a spin out.
That can only be solved by using slim profile and stiff rudders. Carbon Fibre is the best solution nowadays.
If you have Lexan rudders, okay, you will always have that problem.
If you have the old black EPO rudders, the problem will be less but still existing. The factories do not such a good job on rudders, even with the white rudders you have a too thick profile that let the rudders stall, if you sheet in too tight and move the rudders extreme.
Solutions are there on the market.

Another practical one: Do not move the rudders so quickly, but try and steer softly that may also help.
Raking the mast needs to be "counter" raked with the rudders, you have to rake them forward, so that the weather helm is gone. But rake only is not the problem for stalling.

Hope this helps a bit. Happy to tell you more.

Fritz

#33978 - 06/03/04 07:59 AM Re: Up Wind rudder stall [Re: jes9613]  
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sail7seas Offline
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Could you release the mainsheet or traveller temporarily to relieve the weather helm and unstall/reattach flow to the rudder?

#33979 - 06/03/04 06:06 PM Re: Up Wind rudder stall [Re: jes9613]  
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dannyb9 Offline
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beaufort, sc
what about your jib halyard tension? if you can't point, maybe your jib luff is sagging. extra jib halyard tension is needed to keep the jib luff wire loaded upwind when the wind builds. what looks good on the beach may not be enough out in a 15- 18kn breeze sailing hard on the wind. if the forestay becomes taught going upwind the jib luff will sag and you wont be able to point.


marsh hawk
#33980 - 06/04/04 06:52 AM Re: Up Wind rudder stall [Re: dannyb9]  
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jes9613 Offline
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Austin Lake MI
Jib halyard tension is such that the rig is somewhat loose (some play in the sidestays) and the forestay is tight. Perhaps I should try to tighten the jib halyard much tighter than I am currently running and see where I am.
It's an '84 boat that I have put an additional 5 hole adjuster to the forestay to get the rig raked back.
Upwind I'm block to block. I appreciate the help are there any additional things I may be missing? Maybe I should take the additional adjuster out and run with a little less rake but a tighter rig?
John

#33981 - 06/04/04 08:01 AM Re: Up Wind rudder stall [Re: jes9613]  
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sail7seas Offline
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FL
I had a similar problem (pointing), it ended up being the 2000 jib. Hobie recut the jib in 2002?
My observation was they removed 1 1/2 of Luff curve, Luff is 5 inches higher, and raised clew.
As for mast rake, at Worlds.
Silvy was raked back (3 up from bottom, jib up 3)
Colby was raked forward (6 up from bottom, jib at bottom)

#33982 - 06/04/04 10:38 AM Re: Up Wind rudder stall [Re: sail7seas]  
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dannyb9 Offline
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yes you need a LOT more tension on your jib halyard. the forestay should have NO tension while you are sailing hard to windward. or on any other point of sail. ALL the load should be on the jib luff wire. the purpose of the forestay is to hold the mast up when the jib is not being used. you need the extra forestay adjuster to let the mast lean back enough to achieve block to block sheeting. and a little slack in the sidestays is good because the mast wont rotate freely if they are too tight. but the forestay should carry no load while sailing. when i set up on the beach i have about 8-12" of slack in the forestay, that means if i pull the slack out of the forestay toward the mast, as high as i can reach,there is about a foot of distance between the slack forestay and the jib luff wire. depending on how hard its blowing. when you are block to block sailing hard into 18 kn, your forestay still needs to have a little slack in it so that the jib luff wire is carrying ALL the load of the mast and mainsheet sheeted to the max- so that the jib luff wire is as straight as possible upwind. a curved jib luff creates a fuller sail which is slow upwind. especially when its blowing. when winds are lighter you dont need as much halyard tension because you shouldn't be sheeting as hard. the goal is to be ALMOST block to block with ALL the load on the jib luff wire and NO tension on the forestay. the forestay should be bowed, the jib wire should be as straight as possible : )

Last edited by dannyb9; 06/04/04 11:11 AM.

marsh hawk
#33983 - 06/04/04 11:10 AM coke or pepsi [Re: dannyb9]  
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sail7seas Offline
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>forestay tension and the number of holes in your forestay adjuster are irrelevant as long as you can lean the mast back far enough to achieve block to block sheeting<

Gavin, gave talks at the end of each day at Youth,Women,M, & GM Worlds.
As I intrepeted it, for the higher wind ranges, he said he was raking way forward COMPARATIVELY to everone else for:
more jib wire luff tension
more leech tension,
to flatten the main more:
He said releasing the jib halyard only decreases all the above.
He said he would prefer to let out the jib & main traveller to depower.

Vs Silvy's setup (Gavin called the OLD school of thought) is similar to what you describe.
(So coke or pepsi?)

#33984 - 06/04/04 12:24 PM Re: coke or pepsi [Re: sail7seas]  
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dannyb9 Offline
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uh, did i suggest releasing jib halyard tension? NOT. i recomend maximum jib halyard tension for all the above reasons


marsh hawk
#33985 - 06/04/04 12:46 PM Re: coke or pepsi [Re: dannyb9]  
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sail7seas Offline
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FL
After re-reading it all, my bad, ...where's the coffee. Cheers

#33986 - 06/04/04 01:36 PM Re: coke or pepsi [Re: sail7seas]  
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jes9613 Offline
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Austin Lake MI
Assuming good wind over the weekend or at least for our tuesday night races I'll really honk down on the jib traveler and see where that gets me relative to the competition.
thanks
John

#33987 - 06/04/04 01:53 PM Re: coke or pepsi [Re: jes9613]  
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dannyb9 Offline
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beaufort, sc
you mean jib halyard, i hope?


marsh hawk
#33988 - 06/04/04 02:00 PM Re: coke or pepsi [Re: sail7seas]  
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mmadge Offline
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Thunder Bay ON CAN
was Gavin still sheeting block to block with this set up?
It seems to me that this set up would favour the pre /02 jibs.What are your thoughts on the new jib cuts.Are they a big advantage?

#33989 - 06/04/04 02:14 PM Re: coke or pepsi [Re: mmadge]  
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jes9613 Offline
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Austin Lake MI
jib halyard of course, my mistake
john

#33990 - 06/04/04 02:54 PM Re: coke or pepsi [Re: mmadge]  
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>was Gavin still sheeting block to block with this set up?<

YES, he stressed he liked a flatter main with mast forward (& for more rig tension). Easing the sheet in the puffs, and travelling out to depower.

>It seems to me that this set up would favour the pre /02 jibs.What are your thoughts on the new jib cuts.Are they a big advantage? <
I do not know if it favors pre /02 jibs.
Yes, post '02 jib points higher with flatter entry, and though not obvious it also backwinds the main less.

#33991 - 06/04/04 06:03 PM Re: Up Wind rudder stall [Re: sail7seas]  
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mmadge Offline
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(Silvy was raked back (3 up from bottom, jib up 3)
Colby was raked forward (6 up from bottom, jib at bottom)
these are the side stays you are talking about?
Not sure how he could go that high up with lots of jib tension and still sheet block to block

#33992 - 06/05/04 06:01 AM Re: Up Wind rudder stall [Re: mmadge]  
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Tom Korz Offline
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Syracuse, NY Hobie Fleet 204
yep, the shrouds were short and you pull like [email]H@#%[/email] on the main sheet. Chris's observations are pretty much how it was.

#33993 - 06/05/04 07:52 AM Re: Up Wind rudder stall [Re: Tom Korz]  
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mmadge Offline
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Thunder Bay ON CAN
Maybe these new ideas on mast rake will elliminate the need for older boats to get all the new fancy gear(low profile blocks,high cut jib clews) that was introduced to accomadate all this idea of extreme mast rack.

#33994 - 06/05/04 08:43 AM Re: Up Wind rudder stall [Re: mmadge]  
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dannyb9 Offline
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i am guessing that the mast forward setup was a result of the very windy conditions at the worlds and a desire to induce a lot of mast bend to flatten the main. the wind was around 20 kn for most of the regatta. sail7 said he was sheeting block to block with extreme mainsheet tension so i guess the modern short block system would still be needed. i am definitely going to try the mast bend thang, my crew and i are pretty light and the sea breeze has been kickin!

Last edited by dannyb9; 06/05/04 08:49 AM.

marsh hawk
#33995 - 06/07/04 06:29 AM Heavy air/rudder stall [Re: sail7seas]  
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CMerrell Offline
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Virginia USA
Heavy air: Since opinions on rig set up seem to diverge as wind speeds increase, it is helpful to know the wind and sea state, and also crew weight, for heavy air rig set up. At the Worlds it looked like they had strong, steady winds and big (6 foot) waves. Also, the top teams were probably around the minimum crew weight. In that case, the Galvin set up makes a lot of sense.

In the same conditions with heavier crews, backing off the jib halyard tension a smidge (.5 to 1 inch) would help to power up the sail plan to get through the waves.

An "old school" technique is to back off jib halyard tension a lot (2 to 3 inches) in strong but very puffy wind. The idea is to spill power from the top of the main sail in the puffs.

At some point the sail plan is taking all the wind power it can stand. Above that the sails need to be depowered and there are many techniques that will work and you can have very different set ups boat to boat. Wind, water and weight (3 W's) all need to be considered. Someone should write a book about that!

Rudder stall: Moving crew weight back on the boat can solve the stall problem. I don't know the theory why (rudder "digs in" more?).

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