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I've had a few rigging adjustments suggested to me and would like some input from some of the old heads here concerning their potential benefits and drawbacks. 

It was suggested to me to loose foot the main.  I have done this and as far as I can tell it sure didn't hurt my light air performance.  The first thing that I noticed was that I got a real nice airfoil shape all the way to the foot of the sail.  I gotta believe that this alone will help the main pull  better.  At the same time I rigged an adjustable outhaul to the main.  This seems logical on its face.  It wasn't any problem to rig and is pretty handy for tweeking the sail shape.  My main concern is whether this will put additional stress on the boom.  Now that all the force is concentrated on each end of the boom will it be subject to breaking easier than before? 

It was also strongly suggested that I move the attachment for the forestay forward a few inches.  I didn't get an explanation as to why that would help.  What should I be looking for as far as changes to my performance if I try this?  I intend to go ahead with this change, but would like to know what to look for as far as improved performance. 

It was also suggested that I run my self tending jib on a traveler.  This seems reasonable.  Has anyone tried this, and what was the outcome?

Al

(07-07-2012, 07:32 AM)Al Stead link Wrote:My main concern is whether this will put additional stress on the boom.  Now that all the force is concentrated on each end of the boom will it be subject to breaking easier than before?

Greetings Al,

My guess is that by moving the sail loads to the end of the boom next to the attachment point of the main sheet tackle, you have reduced the boom to a simple column. By eliminating all of the bendy forces, your boom now only has to handle compression forces, and should be less stressed overall.

Cheers,
Tom

A loose footed main draws well in light to moderate wind strengths, but progressively gets worse as winds build up, causing the sail to shake and tear itself up. A sail designed to have an attached foot is cut differently than a sail with a loose foot. This means if you make the change one way or the other, the sail doesn't set as well. I like loose footed sails, but wouldn't own one on a deep water boat that could see big winds.

A loose footed boom is under more strain than an attach foot boom. This is because all the forces are localized at two points. The attached foot sail spreads the loads along the full length of the boom.

In short, if you have an attached foot sail, you should leave it this way, or have it recut to remove the foot round and "tuck" in the lower panels. If you have a loose foot sail, it's easier to make it an attached foot, but again the lower panels need rounding and tuck put in by a sail maker, so it'll have good shape, across a wide range of wind strengths.

As to the headstay move, I'm not sure of the logic there.

A self tending jib needs a traveler to get better purchase angles on the boom. This can be done several different ways; a horse, a bridle, and up and back tackle arrangement, etc. each has good and bad things to consider. It's often a good idea to have a length of line dangling from the clew, so you can use it as a "Barber Hauler" on the occasions you want to move the traveler over it's natural "set".

I used a combination on Fat Chance.  The sail was made to fly with a loose foot, but it actually set a bit better when I laced the first 18" or so of the foot to the boom.  This also allowed the outhaul to be more effective.

By moving the forestay forward a bit you will be moving the CE of the sail plan forward a bit, reducing weather helm.

I think instead of adding a traveler to the club foot, if you really want to improve performance, toss the club foot overboard and sheet the jib with two sheets with blocks you can adjust to help control the twist in the jib as the wind builds.

Or just rig a Barber hauler . . . I agree the best thing you can do it toss the boom and use a 100% or 110% jib for the working sail and maybe a 130% for light air. Moving the headstay a few inches will not really effect the CE that much (about a 1/4 of a percent), but a longer sprit with the headstay moving a foot or more will. The vast majority of time, complaints of weather helm (all boats) can be traced to a few common issues, none of which has anything to do with the rig or location of the CE. With gaffers, it's almost always poorly setting sails or over sheeting issues, not actual weather helm. The first thing I check with weather helm complaints, is the rudder deflection on a close hauled course in 10 knots of wind. Of course all the while with an eye on sail trim.

As an example a buddy got a good deal on an old 1/4 ton IOR boat. It was in good shape and he complained of the awful weather helm. We went for a ride and I let him sail as he usually did. 8 knots, with occasional gusts to 12, perfect to check her out. The sails were worn, but okay in this wind strength. Rudder defection was 3 degrees close hauled. So, I looked around and the windward tells were dancing on the main and the upper and lower leeward tells on the jib were dancing, plus the traveler was midship. I asked if he used the traveler and he said hardly ever. The boat was doing about 6 knots. I took the helm, eased the jib a touch and depowered a by moving the jib track car. The boat picked up to 6.1 knots. I then eased the main and adjusted the traveler and the boat picked up to 6.3 knots. This was a 5% increase in boat speed and the boat's heel angle decreased a couple of degrees. The helm instantly eased and still showed 3 degrees of deflection. Now, I was pretty familiar with this old Peterson 25, having owned one years ago, but the same results could have been had by any one reading the tells and adjusting the traveler to windward. No weather helm just worn sails that were overly "powered up" and over sheeted, for the wind conditions, causing excessive heel and partial stalling on both sails. Once the boat was in the groove, he could hold it there with little difficulty (this boat has a fairly fat groove). I gave him a little "cheat sheet" about reading tells and if he memorizes it, he'll be a much better sailor.

Paul,

I've noticed that if I am having trouble with weather helm I can simply plop my butt out on the combings and she will stand right up and the weather helm will all but disappear.  My thinking is that hull shape in the water has a lot to do with how hard I have to manhandle the wheel.  Do you think that the hard chine of my flat bottomed boat has an effect on this more  so than a rounded bilge hull? 

Al

By getting up on the rail, you decrease the asymmetric shape of the waterline, as it passes through the water. As a boat heels over (assuming it's reasonably well balanced), it picks up a natural tendency to steer up into the wind, which you fight by pulling the helm the other way. The more she heels over the worse this gets, regardless of hull shape, though some hull shapes are not as good as others. Hard chine designs can be "hard mouthed" in this regard, because of the drag associated with a deeply immersed chine, though round bilge boats also suffer from this. In a nut shell what's happening is, the wider stern is getting pushed into the water, so it fights back by levering the bow around  and the boat tries to 'round up. Double ended hulls are better at this, but can have their own unique issues in this area.

On a Boat like a Weekender, you can slide you butt around, to make adjustments. We experts call this the organic CB (Center of Butt) and it's the difference between good dinghy and small boat skippers and race winning sailors. Sliding you butt forward will cause the boat to trend into the wind further, while sliding you butt aft will cause the boat to bear away from the wind. In fact, you can steer the boat with a level of precision this way. Of course if you want to tack, you have to run from the stern to the bow and when the boat comes through the eyes of the wind, you have to run back to the cockpit. That's a bit more work then most are willing to preform, but it works.

Lastly, boat's generally shaped like yours will prefer to sail upright, with limited angles of heel, for best results. This means you do everything it takes to keep her "on her feet" and at optimum heel angles. If you find you're jumping up on the rail a lot, it's obviously time to reef or check sail trim (over sheeted). Over sheeting will cause the boat to heel more and sail slower, although it seems like you're going faster. All boats have a "sweet spot" or what we call the groove, whee she does her best in the given wind strength and point of sail. Make a mental note of this things and try to keep her "in the groove" as best as you can. The skippers that win Americas Cups aren't better than other skippers so much, as they've kept their boat in the groove longer than the other guy. All sailing is meandering in and out of the groove. Those that can hold it longer, go faster and further.

Thanks Paul,

The reason I asked is that when I was breaking in my new outboard, I found that with no sails up and the rudder locked in neutral, I could steer the boat by standing in the cabin leaning on the boom and merely shifting my weight from one side to the other.  I found that the boat would veer away from the side that had the chine digging into the water.  The farther I forced the chine down, the quicker she would veer away.  It was kind of fun.  I passed a couple other boats standing around in the cabin and I'm sure the were thinking Who's driving that boat.

As I was going along it occured to me that the water was impacting the curved side of the bow on the side that was down and being deflected causing pressure on that side moving the bow away from it.  Right? Wrong?

Al

It's more complicated than that, but it's good enough for a basic explanation.