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Old 23-02-2015, 14:18   #31
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Re: Weatherhelm Advice, Seeking Balance

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Originally Posted by pete33458 View Post
What does he know???

Let's take a hypothetical where you are using a roller furling headsail and you have furled it all the way up until only 5% or so of the sail is set. Clearly, the CE of the headsail is well forward. Would this move the overall CE forward? I don't think so.

Are there people out there that put a smaller jib on, without changing the main, specifically to reduce weather helm? This goes against my experience and everything I was ever taught, which is to reduce mainsail area first. But I guess I could be wrong. And every boat is a little different. Some boats are a lot different. Pete
here's a depiction of what's going on. The red lines in the picture guesstimate a 150 genoa, the blue star is it's CE and the Red star an approximation of the total CE moving aft, as compared with the original jib.
I guess Ted Brewer knows nothing but this is the way "dummies" like him and other designers have been predicting it for decades...
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Old 23-02-2015, 14:23   #32
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Re: Weatherhelm Advice, Seeking Balance

[QUOTE=RDW;1757235]
Quote:
Originally Posted by D.C.Y. View Post
I have a 1965 Alberg 35. She has a degree of weather-helm.

I may just be too concrete in my reading but 1 degree of weather helm is about as good as it gets. What I think I am saying is that if you have to turn your wheel or tiller 1 degree to sail the course you want, than that is 1 degree of weather helm. Up to 4-5 is fine. The more weather helm the more you have to turn your rudder, the more rudder drag you have i.e. less effecient.
I also think a little weather helm is a little bit of a safety factor. If you become over powered the boat will turn into the wind and loss power.
I am a beginner but in reading about using wind vanes, your boat has to be very balanced to have the vane work good. In acchieving that well balanced sail configuration I think you should expect a little loss of speed.
I would be interested you your experts opinions on my post!!??
RDW
4-6% of weather helm is, in general, optimal. The reason is that the keel of your boat acts like a wing, just like the sail plan, creating areas of low and high pressure. 4-6% creates a low pressure area on the windward side of the keel which helps to reduce leeway through the water.

Above ~6% the positive impact is offset by rudder drag.
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Old 23-02-2015, 14:37   #33
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Re: Weatherhelm Advice, Seeking Balance

Quote:
Originally Posted by Cheechako View Post
here's a depiction of what's going on. The red lines in the picture guesstimate a 150 genoa, the blue star is it's CE and the Red star an approximation of the total CE moving aft, as compared with the original jib.
I guess Ted Brewer knows nothing but this is the way "dummies" like him and other designers have been predicting it for decades...

Your drawing mentions proper sheet leads. One further complication for the OP is that the Alberg 35 sheets lead to the rail so he can't sheet in as tight as he'd like.


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Old 23-02-2015, 15:35   #34
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Re: Weatherhelm Advice, Seeking Balance

ok everybody, i missed the 150 genoa in the original post, so just forget it And I wasn't being serious about Ted Brewer. Take a pill. pete
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Old 23-02-2015, 17:41   #35
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Re: Weatherhelm Advice, Seeking Balance

Thank you for the posts and lively debates. I may see if I can get a new Doyle 2x2 main (with reefing points) to go with the new 100% foresail we found on board. First things first, maybe with a fresh mainsail that has the ability to reef we can see what she really sails like and work on those tuning and trimming notes. Your responses to this post were completely educational, thank you for your consideration and taking the time to share your experience an ideas.
Chad ~ Procyon


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Old 23-02-2015, 18:14   #36
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Re: Weatherhelm Advice, Seeking Balance

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Originally Posted by Tayana42 View Post
Your drawing mentions proper sheet leads. One further complication for the OP is that the Alberg 35 sheets lead to the rail so he can't sheet in as tight as he'd like.


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Not sheet leads. Lead is the term for the distance from the CLR to the CE. See diagram...
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Old 23-02-2015, 18:19   #37
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Re: Weatherhelm Advice, Seeking Balance

So, to carry it to the logical next step...

When the wind picks up, and I notice weather helm developing, some of your ideas suggest that I can make that better by not reefing my main and and instead putting up a genoa with a greater overlap to move the CE aft... Not my experience. YMMV.
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Old 23-02-2015, 19:10   #38
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Re: Weatherhelm Advice, Seeking Balance

Most boats should be in good balance with full sail in around 10 to 12 knots of wind. If at that speed you have excessive weather helm then the forestay length my need to be shortened. As the wind picks up and you start to heel more the only way you are going to keep in balance is to reduce drive from mainsail leech. That inch or two on the forestay is not going to account for much then. You can take the main down and have all the sail up forward, but if you have too much heel you got too much weather helm and there is no changing that correlation. Any body whose been on a beam reach with a spinnaker knows you can dump the main, but there comes a point when it's all over.
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Old 23-02-2015, 19:53   #39
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Re: Weatherhelm Advice, Seeking Balance

D.C.Y.

Good on ya, mate. The new sail should make a huge lot of difference. Your plan for getting to know the boat better sounds good & practical. I would imagine the 150 genoa that you blew out was intended as a light air sail, though one of our boats had both a heavy and a light air 165. Both used as upwind sails. Spinnaker off the wind. on that boat, or wing and wing, when we were lazy.

At this point, it might be useful to check if the headstay turnbuckle is indeed bottomed out. If not, I would not change that until you can determine what the length should be, possibly through the Allberg Owners Club. That's a lot of wire to remove. Do you know the age of the rigging wire? If over 10 yrs., it is common to replace with new 316 1 x 19, and an opportunity to shift to Norseman or Sta-Loks. The next time you replace the wire, the DIY fittings shall have paid for themselves, and they give you the ability to make repairs in remote locations.

Cheers,

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Old 23-02-2015, 20:28   #40
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Re: Weatherhelm Advice, Seeking Balance

Standing Rigging was like new, installed in 2009. The owner was elderly and did not sail often. Procyon had been indoors at Martha's Vineyard Shipyard for 4 years. The Yanmar diesel only had 108 hrs on her and she was also 2009. I am of the understanding that the 100 foresail was new in 2009 also and rarely ever used. The main and the 150 (that blew out in October) seemed to have lots more years and wear on them. No reefing points indicate it was outfitted when the owner was still using the rolling reefing. There were lazy jacks on the boat when I found her. Looking Forward to May!!!



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Old 23-02-2015, 20:48   #41
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Re: Weatherhelm Advice, Seeking Balance

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Originally Posted by sanibel sailor View Post
Not sheet leads. Lead is the term for the distance from the CLR to the CE. See diagram...

Sanibel Sailor, you are right of course. Thanks for the correction.


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Old 23-02-2015, 21:08   #42
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Re: Weatherhelm Advice, Seeking Balance

To the poster who asked about boat speed and wind vane use,

We found that speed through the water was not affected; however, the course was generally less exact than an electronic autopilot, it "hunted" more. Saying that, however, it gave us on our boat with a 29 foot waterline, a long term at sea average of 140 n. mi. per day. And once, of 159.5 on a hurried trip, Noumea to Gladstone, to escape a cyclone.

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Old 23-02-2015, 23:56   #43
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Re: Weatherhelm Advice, Seeking Balance

Definitely considers the sails as suspect first. Old sails go draft aft and severely affect weather helm. Reducing the size of the headsail may actually improve things. Many boats sail with weather helm with only the headsail set in anycase so it is not that simple. I had a Macgregor 65 with old sails that was struggling to do 130 degrees through the wind. The wake aft was off at a 30 degree angle. New sails transformed the boat.

regards

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Old 24-02-2015, 07:50   #44
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Re: Weatherhelm Advice, Seeking Balance

I am still having some difficulty with the physics (and changes to the Ce of the overall sailplan and not just the headsail with different headsails/reefs). Early in my sailing life I had a folkboat that could be balanced to have a completely neutral helm upwind/close reaching with proper sail trim. She would head up in the puffs (short of luffing) and off in the lulls. I had three jibs - a 130%, a 100% working jib and a storm jib. To achieve a neutral helm, I needed a single reef in the main with the 130% and a double reef with the 100 ( I could not achieve a neutral helm with the storm jib, not surprisingly). Regardless, going to a smaller headsail required a corresponding reduction in the mainsail to maintain balance. If I had the 130 without a reef in the main (or the 100 without a double reef), she had slight weather helm.

In any event, I think this also supports the sage advice that in order to maintain balance, one should always reef the main first.

Brad
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Old 24-02-2015, 16:48   #45
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Re: Weatherhelm Advice, Seeking Balance

Somebody already mentioned it earlier, its not so much the for and aft of the CE. It's the heeling that moves the CE outboard to leeward that has the largest effect on weather helm.

As for blown out verses new sails, in Tom Widdens book "ART and Science of Sails" He shows how moving the draft aft towards 50% in the sail actually makes the sail faster, but also narrows the sweet spot of the groove making it harder to keep in. When I was racing I always had my sailmaker move the draft farther aft from where he normally would start out. I don't think draft migrating aft in older sails has anything to do with weather helm. The OP. needs reef points to solve his problem.
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