Lee helm

Submitted by aposner on Sun, 07/25/2010 - 08:00
I'm having a strange problem with my FS and hope someone can give me a few suggestions. I have a snug rig with North sails. Crew weight is about 320 lbs and we're sitting on the rail. I find that in winds over 15 kts, not only am I overpowered, but the boat develops lee helm. i.e. when I heel too much and try to feather into the wind and let out the main, the boat "falls off" rather than "heads up" and I have to push the tiller to lee just to keep it from continuing to fall off. Finally when the wind puff lets up the boat finally heads up. In heavy conditions I have the boom vang tight, the outhaul tight, the Cunningham tight, and the jib lead blocks as far aft as they go. The board is all the way down. I've had some near capsizes because of this action (and of course it slows me down), so I'm quite concerned. In light air the boat sails like a dream. Please help.
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Comments

Maybe you don't have enough rake.

Submitted by glbennett on Sun, 07/25/2010 - 11:43.
Maybe you don't have enough rake. What is your rake measurement?

28.

Submitted by aposner on Sun, 07/25/2010 - 11:49.
28.5 inches

Also, check the tension on the forestay.

Submitted by sawyerspadre on Sun, 07/25/2010 - 18:39.
Also, check the tension on the forestay. About how old is your boat? is the rudder in the normal configuration, or altered? When the boat "falls off" is it staying heeled or flattening and rolling to weather as you leave the main out? I would agree that rake seems to be the culprit. Also, is you board going all the way down? If the cable is too short, the boat likely won't hunt up into the breeze. How is your pointing? Phil Scheetz FS 4086

Phil Scheetz

FS 4086

Fleet 163, Nockamixon Sail Club

Thanks for the responses so far.

Submitted by aposner on Sun, 07/25/2010 - 18:57.
Thanks for the responses so far. The forestay tension is about 80 lbs. The boat was bought new about 3 years ago. When it falls off it actually heels more (that's what's so scary). The board does go all the way down. It's doesn't point well at all. The only other Scot in my fleet points much better. Do you think I should increase the rake to less than 28.5 inches (which is what is recommended by North Sails? Alan

Alan, I think what you describe is more common when sailing wit

Submitted by Dave812 on Sun, 07/25/2010 - 20:03.
Alan, I think what you describe is more common when sailing with light crew weight. I sail at about 305 lbs and have experience the same thing. Sounds like your rake is fine and you know the board goes fully down. Also if the boat is well balanced in 10 to 12 knots your rake is probably ok. Here is what we do; when a puff comes that causes more heel than we want I will ease the main. When this happens the slight (and normal) weather helm increases a little especially if I let the boat heel. Assuming I ease the main promptly and prevent excess heeling the helm may lighten up a little. As the wind builds up you reach a point when only easing the main results in lee helm and more heeling than ideal. How quickly you reach this point depends on crew weight. So once the lee helm starts my crew eases the jib in the puffs along with the main. A little jib ease goes a long way, it doesn't take that much to keep the boat balanced. If you are sailing in very flat water you may be able to ease less and pinch up in the puffs, but that is not so good in chop. Hope this helps.

Dave, Thanks for the advice.

Submitted by aposner on Sun, 07/25/2010 - 22:19.
Dave, Thanks for the advice. Glad to hear it's not just my boat. I'll give your suggestion about easing the jib a try. Alan

One other thing to check is the centerboard "full" down position

Submitted by karafiath on Mon, 07/26/2010 - 13:14.
One other thing to check is the centerboard "full" down position. Going widward, the boat pretty steering much balances on the centerboard. To reduce leward helm you want the underwater part of centerboard as far forward as possible and the above part where the rollers are as far back as possible. This increases the moment arm associated with mainsail forces and decreases the jib moment arm. On my boat, when lowered, the centerboard tends to stop with the rollers right at the bottom of the curved part of the trunk. The rollers can come back further on the flat part of the centerboard trunk another two or three inches. Head into the wind a bit and then the crew can easily maneuver the rollers back. make sure that you have enough line on the centerboard uphaul. If not, take a turn off the drum. You can check all this out while at the dock with no sails up.Gabor FS 3512

Lee helm when overpowered in heavy air is probably a technique p

Submitted by Jay Lott on Fri, 07/30/2010 - 06:43.
Lee helm when overpowered in heavy air is probably a technique problem, not a rigging problem. First, do everything else you can to keep the boat flat, like maxing the outhaul, cunningham, vang and then hike hike hike...only then do you start easing the main to keep the boat flat. When sailing upwind, if the mainsail is eased so far as to luff it all the way back to the leech, then you will experience lee helm. It's important to keep at least the leech of the main full of wind, in order to keep pressing downwind on the aft end of the boat, which creates weather helm. To avoid this problem, anticipate the puffs, luff your main (partway so the leech is not luffed) immediately when the puff hits or just before, increase your skill at "feathering" the boat upwind (the closer you sail to the wind the less you will need to luff the main) and if all that fails and you are experiencing lee helm, ease the jib (probably not all the way) along with the main until the boat flattens, then feather the boat again, trim in and go. For really big puffs you could do what a previous poster suggested, ease both the jib (a little) and the main (a lot) just when the puff hits. With practice you will be able to keep the pressure on the leech of your main in more and more wind. Jay Lott FS 5698

Jay, Thanks for your suggestions.

Submitted by aposner on Fri, 07/30/2010 - 06:54.
Jay, Thanks for your suggestions. Actually you're right. The severe lee helm I notice usually occurs when I let the main "all the way out" i.e. entire main is luffing. Can't wait to try these techniques. Unfortunately the winds are predicted to be zero kts. here this Saturday.