Hunter 23 weather helm

[ChrisM]

Learned quite a lesson in rig tuning this past weekend! Ever since I started sailing my H23 it has demonstrated considerable weatherhelm, to the point where any time I was heeling over more than 5-10 degrees I would have to put considerable effort on the tiller, and actually steer hard toward leeward just to keep from rounding up into the wind. Besides the fatigue from putting so much effort on the tiller, I also was losing considerable speed due to the extra resistance of the rudder in the water, and if the wind would die down suddenly I would turn leeward rather quickly. I mentioned this to another sailor in the marina, Tom, who bought his Catalina 25 in 1978 and has been sailing it ever since, and he commented on how he and some of the other sailors had just been commenting on the rake of my mast, and how I had to be having that problem. He suggested that I shorten my forestay and lengthen my backstays by adjusting my turnbuckles. I set out to do just that last Sunday. After loosening my shrouds and backstay, I went to the anchor locker to tighten my forestay. I was dismayed to find out I did not have a turnbuckle to tighten. A roller furler is installed, and I went off to find Tom to ask his advice.

Tom appraised the situation and quickly came to the conclusion that needed to remove a metal extender that was on the forestay, and install extenders on the split backstay. These amounted to about 1-1/2"of shortening/lengthening. Once I moved everything around and tightened the stays and shrouds, I headed out for the water.

Wow what a difference! The boat handles TOTALLY different when heeled over. Instead of trying to round up, it digs in and accelerates (or continues to heel even more until I adjust the sheets ) I made 7.4 MPH on my garmin that afternoon with my 150 genoa out. I am going to make some fine adjustments this weekend, I may have too little weatherhelm, and possibly some leehelm, but I'll figure that out. I had my daughter (age 11) on the tiller late Sunday and she heeled the boat over a couple of times to where the stanchions were in the water a couple of inches. A little disconcerting, but exciting.

Cheers,

Chris

 

[Alan]

It's all about rig tuning. Rather than play the guessing game, set your mast rake at 1%. That should be a reasonable setting. On your boat 1% is 3.5". Then go ahead and tune the rest of the rig. You should have a small amount of weather helm when finished. That is a good thing and a safety factor. Lee helm is dangerous.

 

[C Jones]

Also check the leading edge of your rudder, if it cracks and starts to delaminate it feels like weather helm. It isnt but it feels like it. You can hardly hold it with 2 hands. I know, mine did.

Alan, thanks for that 1% info. After my roller furler was installed 3.5" is what I ended up with.

 

[Alan]

C Jones,

That (1%) should give you just a slight weather helm. If you sail in light conditions you could increase the rake and you will notice that the boat will point much better. Up to 2% should still be quite manageable. I use nearly 3% on my boat but the deep fin keel is a factor. The rigging numbers are just a guide and are variable for different boats and conditions.

 

[C Jones]

Alan, Thanks for the 2% tip on getting it to point better in low wind. These shallow wing keels are good for speed and shallow water but point badly. The Catalina's and Bene's with them point as far off as I do or worst.

 

[isaksp00]

How do you measure the mast rake?

Once (if) I get my outboard running, I'll be launching a '91 H23 soon (the first time for me - bought it a few months ago). This thread on tuning is very interesting, but I don't see how you can measure a 1 or 2% rake - how do you determine that the masthead is actually (say) 3.5 inches aft of vertical? What measurement technique do you use?

 

[Alan]

Good question! Hang a plumb bob (or some pointy weight) off the main halyard so that it is suspended just above the boom. Measure back from the back edge of the mast to the center of the weight. That will give you a measure in inches. Divide that number by the height of the mast from the gooseneck (the "P" is close enough). In the case of the H23 it's 25' 8". Round it off the 26' or 312 inches. Multiply that number by 100 to get the percent of rake. Roughly 3.25" is a 1% rake. If it's close to that you can leave the adjustment alone. If you sail in relatively lighter airs you can increase that number to 2% for a better performance. The determining factor is how much weather helm builds up as a result of the rake increase. The more rake the better performance but a corresponding increase in weather helm.

 

[isaksp00]

Thanks! I can use the plumb line to check mast angle side-to-side as well.

What's the theory here? Does added rake bend the mast to be more of a curve, or just lean it back? Is the idea that a flatter (less curvy) luff keeps the main flatter (less like an airplane wing) and thus generating less power, so there is less weather helm - an obvioulsy vice-versa, sail with more curve is more powerful? Mine has a rolling furling jib (no turnbuckle on forestay), so I'm not sure whether the split backstay turnbuckle is actually effective in adjusting rake.

 

[Alan]

Rake is adjusted on a straight untensioned mast. Prebend will distort the rake measurement. I had a look at the pictures of 23's on this site and cannot see a forestay turnbuckle. However there must be some way to adjust the length to set mast rake. Rake is adjusted with all shrouds loose. Then the mast is adjusted for in column(or side to side). Last the tension is applied to the shrouds equally. After tuning the mast sighting up the luff grove should reveal a perfctly straight grove that may curve aft. The backstay has nothing whatever to do with mast rake. A backstay tensioner is used to bend the mast back which flattens and de-powers the main in heavier air. If you had a jumper strut on the mast of a fractional rig the backstay tensioner would simultaneously flatten the main and tension the forestay flattening the headsail also.