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post #11 of 18 Old 06-22-2009
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I also have a swing keel.. We had a problem with the line that held our swing rudder in the down position.. it would drift up and do what you describe with just a 5deg heel.. I was constantly stepping over the back of the boat and pushing the rudder straight down.. finally got around to drilling out and replacing the line, Problem Solved !!


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post #12 of 18 Old 06-22-2009
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The advice so far is missing something. Your rudder is losing flow easily. Could be bad design. When you lose flow the rudder stalls and you round up=no fun. As a work around, try pumping the tiller hard several times and I mean hard as soon as you start to feel a puff. This should help reattach the flow. Short term solution to what might be a long term problem.
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post #13 of 18 Old 06-22-2009
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Another variable that could be causing you to 'round up is how full your mainsail is. A bellying sail on a reach, especially if it's bellying at the top, creates a lot of pull, and can swing your center of effort (there's that expression again!) behind your center of lateral resistance. In a centerboard boat, raising the board a bit could help balance the two forces better. In your case, with a swing keel being (you hope) fixed down, tightening the boom vang might help flatten the sail and reduce the heeling moment that may be swinging you into the wind. Cranking in the vang when on a reach might be worth trying. Let us know what works!
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post #14 of 18 Old 06-22-2009 Thread Starter
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Thanks for all of the great responses! It could be that what I'm experiencing is simply weatherhelm. 20 years ago I spent a lot of time sailing my Flying Scot. My International 23 is a very different boat. I'll have to spend more time sailing her and figuring this out.

The weatherhelm does occur when pointing up into the wind and the sheets pulled tight, we start to heel more than 15*, get a gust of wind and around she goes! I probably need to start letting the sheets out when the wind picks up.
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post #15 of 18 Old 07-07-2009
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As stated above, you are experiencing Weather Helm. This is where the boat wants to turn itself into the wind while sailing/heeling. The opposite is Lee Helm where the boat wants to turn "away" or "down" wind while sailing/heeling. This is a Sail/Mast/Rig Tune Up problem. It may also be a result of your swing keel not being lower properly or all the way down in the keel/centerboard trunk.
1) Make sure your mast is vertical side-to-side. Duct tape a tape measure to your Main Halyard. Hoist the tape and halyard up to the top of the mast. Place the lower end of the tape measure at the base of your side stay/shroud turn buckle on the Starboard side. Make note of the measurement. Do the same on the Port turn buckle. Is the measurement the same? If not, adjust your side stays until the measurements match. Once done, you are confident the mast of vertical side-to-side.
2) Adjust the mast Fore and Aft (front to back). If you are experiencing Weather Helm (where you must put the tiller to windward while sailing in order to keep the boat from rounding up into the wind) you need to tilt the entire mast rig Forward. Experiment until the weather helm stops. This means loosening your backstay(s) and shrouds and tightening the forestay a 1/4 or so at a time until the boat is tuned and the weather helm all but dissapears. What is ideal? When there is just a slight bit of weather helm. Some weather helm is necessary as a safety element; if you really get knocked by a blow, you want the boat to round up into the wind and luff to safety.
3) Also check your swing keel. All of the above is to be done with the swing keel lowered all the way down. If it is stuck, the boat will not sail or perform as designed. If you have clear water, lower the keel and swim under the hull with a dive mask and inspect to make sure the keel is all the way down. Finally, and if you ahave a "kick up" rudder that it remains in the down position while underway. They sometimes tend to lift up at higher speeds. This will greatly effect your Tuned Boat performance. Be sure rudder is locked in the down position.
P.S. These elements of tuning effect what is called Center of Lateral Resistance (CLR). If you want more technical specifics read about CLR in a good sailing book.

A finely tuned boat nearly eliminates skipper fatigue at the helm and is a joy to sail!
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post #16 of 18 Old 07-08-2009 Thread Starter
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Thank you BradleyK!!

I'm certain my keel is all the way down, so I'll check into the other things you detailed. Thanks again!
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post #17 of 18 Old 07-08-2009
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Most swing keels swing down and forward; if they aren't lowered all the way, the boat will exhibit LEE helm rather than WEATHER helm. The nose will head DOWN. On badly overpowered, mainsail-biased boats like our Bucc18, the swing centerboard must be raised about halfway to stop it rounding up in higher winds -- it moves the CLR aft. This is not always a good idea on boats with ballasted swing keels, however. Depends on the boat.

You say the rounding occurs on a "close reach". That's interesting. You may indeed be stalling the main. Try sheeting out until the luff pocket gets 'soft'. Oversheeting on reaches is a common practise. Trim the jib to the wind and the main to the jib.

Does your main have reef points? I bet your boat would behave very well with about 40" taken out of the foot of the main. May even sail faster, because fighting the tiller is SLOW. Fifteen knots is about where we reef the SJ21, and the helm goes right back to neutral. As others have mentioned, your rudder may be damaged or of a non-foil design. I've seen some that are just slabs of wood; knew one guy who couldn't get his boat to steer because the PO had bolted the rudder blade on backwards! A rudder that is inefficient requires more aggressive tiller work, which leads to stalling and flow that detaches too early. Kind of a feedback loop.

One possibility that hasn't been mentioned is hull trim. Does your boat sit level on her lines? If she is down in the bows (like if you just added a bunch of anchor chain or are sailing below designed crew weight) she will tend to dig in up front & slew wide at the stern. Subtly different feel than a rounding up. Let us know what you figure out!

Buccaneer18, Grainnia
SJ21, Diarmuid
Albin Ballad 30, Fionn

Last edited by bobmcgov; 07-08-2009 at 06:14 PM.
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post #18 of 18 Old 07-08-2009 Thread Starter
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Thanks Bob, I'll also take your advice into consideration!
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