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Up Wind rudder stall

Posted By: jes9613

Up Wind rudder stall - 06/02/04 12:45 PM

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
Posted By: Fritz

Re: Up Wind rudder stall - 06/02/04 09:11 PM

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
Posted By: sail7seas

Re: Up Wind rudder stall - 06/03/04 01:59 PM

Could you release the mainsheet or traveller temporarily to relieve the weather helm and unstall/reattach flow to the rudder?
Posted By: dannyb9

Re: Up Wind rudder stall - 06/04/04 12:06 AM

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.
Posted By: jes9613

Re: Up Wind rudder stall - 06/04/04 12:52 PM

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
Posted By: sail7seas

Re: Up Wind rudder stall - 06/04/04 02:01 PM

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)
Posted By: dannyb9

Re: Up Wind rudder stall - 06/04/04 04:38 PM

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 : )
Posted By: sail7seas

coke or pepsi - 06/04/04 05:10 PM

>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?)
Posted By: dannyb9

Re: coke or pepsi - 06/04/04 06:24 PM

uh, did i suggest releasing jib halyard tension? NOT. i recomend maximum jib halyard tension for all the above reasons
Posted By: sail7seas

Re: coke or pepsi - 06/04/04 06:46 PM

After re-reading it all, my bad, ...where's the coffee. Cheers
Posted By: jes9613

Re: coke or pepsi - 06/04/04 07:36 PM

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
Posted By: dannyb9

Re: coke or pepsi - 06/04/04 07:53 PM

you mean jib halyard, i hope?
Posted By: mmadge

Re: coke or pepsi - 06/04/04 08:00 PM

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?
Posted By: jes9613

Re: coke or pepsi - 06/04/04 08:14 PM

jib halyard of course, my mistake
john
Posted By: sail7seas

Re: coke or pepsi - 06/04/04 08:54 PM

>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.
Posted By: mmadge

Re: Up Wind rudder stall - 06/05/04 12:03 AM

(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
Posted By: Tom Korz

Re: Up Wind rudder stall - 06/05/04 12:01 PM

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.
Posted By: mmadge

Re: Up Wind rudder stall - 06/05/04 01:52 PM

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.
Posted By: dannyb9

Re: Up Wind rudder stall - 06/05/04 02:43 PM

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!
Posted By: CMerrell

Heavy air/rudder stall - 06/07/04 12:29 PM

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?).
Posted By: mbounds

Re: Heavy air/rudder stall - 06/07/04 06:42 PM

Wind conditions at the 16 Worlds were rarely above 15 kts in the Open event.

There were big waves which necessitated a lot of power in the rig, especially if you were significantly (>10 lbs) over minimum weight.

All kinds of tricks were done with the mainsheet blocks to get more rake - smaller triple block on the boom, bitter end of the sheet led under one side of the cleat support arm on the ratchet to allow the blocks to 2-block closer together.

We took over one boat from Juan I. Maegli (4th overall). They were at minimum weight and were carrying 20" of rake (measured with the main halyard). The jib clew plate was touching the front crossbar. Shrouds were in the 3rd hole from the bottom in the adjuster.

Fluffy & I reset the rig since we were a little heavier (295#) - moved shrouds up one hole, 16" of rake. During the next race, the conditions were about 10 kts (crew trapezing, skipper hiking) and big waves. We were travelled off about 4" on the main to keep the leech from stalling and about 4" out on the jib to keep the slot open. Mainsheet was two-blocked. We ended up 10th in the race. Our upwind speed / pointing ability was as good or better than anybody else's. Downwind we were a rocketship. We would have done better if I hadn't misjudged the layline to the weather mark, requiring a double tack in traffic.
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