All things stretch under load and have different acceptable tolerances. Lines, Wire, Sails. Stretch them within their limits and they return to normal. Stretch things beyond their limits and Lines and Wire snap, and sailcloth tears.
Sailcloth stretches in higher wind, and/or more tension of the halyard, outhaul, mainsheet, cunningham. I believe the sailmaker cuts the sail to fit between the black bands at a certain wind speed, say 8 or 10 knots. In areas known for higher winds, he may cut the sail flatter and to reach full hoist in 15 knots? Below that, the halyard can be a little slack to prevent the vertical wrinkle behind the mast that kills flow and indicates over tension. Ease a little halyard and cloth smoothes out. Short horizontal wrinkles from head to tack are OK in light winds, called speed wrinkles. As wind increases, the halyard can be tensioned to keep the draft forward of 50%, until the head reaches the upper black band. If more luff tension is needed, the Cunningham is employed to remove any horizontal wrinkles, smooth the sailcloth and pull the draft forward. Tip: mark main and jib halyard, cunningham, outhaul; to prevent overtension, and prevent damage to your sails. One method, make a black line with a laundry marker, around the line where it intersects the winch drum or cam cleat. Make at least three marks per line; Low, Med, High settings. Tip: don't tension a halyard when loaded up. Instead, tension the halyard when it is lightly loaded or in the middle of a tacking maneuver when the wind is on both sides of the sail. Chuck Resolute 1990 C&C 34R Atlantic City, NJ ----- Original Message ----- From: "Josh Muckley" <muckl...@gmail.com> To: cnc-list@cnc-list.com Sent: Sunday, August 18, 2013 12:02:36 PM Subject: Re: Stus-List Cunningham Hmmm...thanks Chuck, I never considered the sail maker cutting the sail longer than the band. I'm pretty sure mine cut it to fit the bands and explained that there would be room for it to stretch (to the band). Additionally if it were cut long and then stretched it could stop or jam in the masthead. Josh -- When privacy matters. http://www.secure-my-email.com On Aug 18, 2013 11:41 AM, "Russ & Melody" < russ...@telus.net > wrote: Thanks Chuck for making this important point regarding the upper black band. A well measured racing main will reach the black band with only low moderate tension on the halyard (for maximum area). No kidding.. foaming at the mouth racers believe even a few centimetres can make the difference. When more luff tension is required it is taken on with the cunningham. The old Harken "Magic Box" , at 8:1 purchase, was made for this purpose. Cheers, Russ Sweet 35 mk-1 At 07:18 AM 18/08/2013, you wrote: <blockquote> Nicely written Josh. I would add the main halyard setup properly, can only be tensioned to raise the sail to the black band. As wind increases, the draft of the mainsail will move aft and the Cunningham is used to add a little more tension along the luff and bring the draft forward into the proper position, 45 to 50%. The Cunningham needs to be eased if the wind dies or turning downwind reduces the pressure on the sail. On bendy rigs like our three spreader rig, adding backstay tension shortens the P dimension, reduces the tension on the main halyard, so we add Cunningham to compensate. We ease the Cunningham before easing backstay as they are related. Easing backstay increases the P dimension and doing so without easing Cunningham or halyard can rip the mainsail. Lesson learned the hard way. Chuck Resolute 1990 C&C 34R Atlantic City, NJ From: "Josh Muckley" < muckl...@gmail.com > To: cnc-list@cnc-list.com Sent: Sunday, August 18, 2013 12:23:16 AM Subject: Re: Stus-List 1985 C&C - 33 Missing Cunningham What do you mean missing? Do you mean you have a jammer that is labelled Cunningham that doesn't have a line running through it? The cunningham opposes the main halyard by pulling down on the tack of the mainsail. So, you can tension the main by pulling up on the head or down on the tack. Usually it is easier and more controlled to use the cunningham but you risk having odd sail shapes if pulled too far. Additionally it is usually desired to hoist the main as high as possible, not down. So, a tight halyard tends to be preferred and the Cunningham is used when tightening the halyard is too difficult or unsafe, such as when the wind pipes up and on a close reach. On your mainsail you should find a metal Cunningham eye about 5-6 inches above the tack ring. Different makers provide different attachments but what I have found works well for me is to create a 2:1 advantage by running a line through the eye and attaching it to the reefing hook/horn just outboard of the tack ring. (Alternatively you could also tie it to the boom.) By pulling down on the free end of the line you will be pulling down on the Cunningham ring with 2x the power. The PO had this free end led to the mast base and back to the cabin top jammer. I regularly had to use a winch to tighten the Cunningham. When I replaced the line I added a 4:1 block and tackle. The 2:1 bitter end stops just below the boom and is finished with an eye. The 4:1 hooks on the eye and attaches to the mast base. The free end of the block and tackle is then led back the the jammer. The 4:1 pulls down on the 2:1 for a total of 8:1. I also used a hook between the 2:1 and 4:1 so that it is easy to disconnect the 4:1 and reattach it to the reefing eye when reefing. Our mainsail has "floppy rings" or "dog bones" that pass through the reefing eye in the sail. They are made of nylon webbing running through the reefing eye and finished off on both ends by stainless rings larger than the eye. Traditionally when reefing you would let the sail down and hook one of the floppy rings to the reefing horn. The ring on the other end of the "dog bone" prevents the nylon webbing from pulling out of the reefing eye and now the main halyard can be pulled tight. While sailing, if you find that there is not enough tension on the halyard you can unhook the Cunningham 4:1 from the 2:1 and re-hook it to the "lazy" ring in the dog bone. You once again have an 8:1 Cunningham, but now on a reefed sail. Arguably, a Cunningham could be considered a fix for a poorly tightened halyard...at least on our "big boats". On some smaller boats the cunningham is the only thing holding the tack ring. But those cunninghams are also held forward ensuring proper foot tension. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD -- When privacy matters. http://www.secure-my-email.com On Aug 17, 2013 12:22 PM, "Raymond Macklin" < ray.mack...@gmail.com > wrote: I purchased a 1985 C&C - 33 and I am missing the cunningham. Does anyone have a diagram of where it runs on the boat or could explain it to me. Thanks, Ray Macklin Libertyville, IL LakeHouse _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com </blockquote> _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
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