weather helm, mast rake H25.5

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Jeff Johnston

My H25.5 is a masthead rig with a single backstay. I just put on new sails. Genoa is rollerfurling 135 or 140. the boat sails better than with the old blown out sails. In a stiff breeze yesterday 15 to 20+ I had too much weather helm. I used the usual controls halyard, outhaul, traveler mainsheet to shape and flatten the sail. I could have traveled out a little farther. I reduced the genoa to about a 100 and moved the leads back to spill air. I also single reefed the main thought I need to change out some control blocks because I did not have enough outhaul tension. I still need to reduce some weather helm. I know on a MacGregor 26s that I own that it is popular to extend the leading edge of the rudder with two more inches of glass. Is a rudder modification needed? I do not think I have excessive mast rake but wonder what is normal for a 25.5. I guess I have questions on where the mast should be tuned in general
 
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Joe Boyette

Can you let the main twist? Keep the genoa leads

close in and tight for less twist? Also can you rake the mast forward any more? On my 25.5 I am experiencing weather helm at 15 to 20+ true...you may be seeing what is "normal" for the 25.5. I usually try to spill air from the main first...
 
Apr 19, 1999
1,670
Pearson Wanderer Titusville, Florida
Depower the main

In 15 to 20 kt you should be depowering the main. You had already increased the halyard tension and outhaul tension. Those were good moves. Reducing the headsail area was also smart, but it didn't help balance your sail plan. You didn't mention a cunningham, which is more effective for tensioning the luff of the sail to move the draft forward. I'd try that first. Then increase sail twist by decreasing leech tension. The easiest way to do this is to increase backstay tension and bend the mast. This will also flatten the sail (an added plus). As the sail twists, the top will spill air and reduce heeling force while the lower portion keeps developing power. This may not work very well with a masthead rig but it's worth a try. The third step (which flies in the face of all convention) is to pull the traveler to windward (yes!) while simultaneously easing the mainsheet. This decreases the downward pull of the mainsheet while maintaining the proper angle of attack of the boom. Leech tension is decreased and there is enough slack in the system so the boom can rise in gusts and open the leech even more. There are still a few tricks left. Move your crew to the windward side of the cockpit, or even better out on the rail. If you're sailing with the lee rail buried, you have too much heel. If you're going to be on the same tack for a while, move some of the stuff belowdecks to the windward side. When all else fails, put in a reef. Happy sailing. Peter H23 "Raven"
 
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Anthony Bavuso

Things I did to solve my weather helm problem.

I noticed similar weather helm problems on my 25.5 also. The suggestions given already are good ones. To solve the problem I purchase new sails. That really helped. I also raked the mast further forward by loosening the backstay and tightening the head stay. Actually I think my head stay turnbuckle is tightened up all the way. The other thing I have done is to increase the prebend in the mast. The prebend helps additionally to flatten the main. But I think for me the most important thing to do on a gusty day is to try to keep the boat from healing past a critical angle maybe 20 degrees or so. As the boat heals past the critical angle the weather helm increases dramatically to the point where only a little piece of the rudder is in the water and the boat heads up to windward uncontrollably. I find the way to avoid this is while sailing in gusty winds is to always have the mainsheet uncleated and in my hand. And as I feel the pressure from the gust I pay some mainsheet out, keeping the boat flat and avoiding the chain of events described above. Then when I feel the boat flattening out I take some line in. This is a constant adjustment process. One other note, as the wind pipes up and you feel your weather helm problem increasing, reducing headsail area will only make your weather helm problem worse. The boat's helm properties are determined by the balance of the weather helm created by the main (since it is behind the center of lateral resistance) and the lee helm created by the headsail (since it is in front on the center of lateral resistance). So you can think of it as a see-saw turned on it's side. Decreasing headsail area and hence the lee helm created by the sail will only increase the effect of the weather helm created by the main. The general rule is to reef your main first. Then if you need to, reef your headsail.
 
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