light wind rigging quandary

[konajoe]

You just disagreed a few posts ago.

[techno900]

I don't think I have contradicted myself, but this is what I am saying:

1. Less downhaul = a fuller sail with a deeper draft & tighter leach
2. More downhaul = a flatter sail with less draft and a loser leach.
3. Less outhaul = a slightly fuller sail, little change in the leach.
4. More outhaul = a slightly flatter sail, little change in the leach.
5. Add downhaul and the outhaul lines slack a bit, but the sail will be flatter with less draft than before the downhaul.
6. Take the slack out of the outhaul and the sail will be even more flat.

When rigging my cambered sails, you do let off the downhaul to snap on the cambers, because the increased draft allows you to rotate the cam in such a way that it snaps on the mast with ease. Trying to snap on the cams with the sail fully downhauled is impossible, which is why the cams won't come off the mast with full downhaul while sailing. Too much or too little downhaul and the cams won't rotate.

[isobars]

My head's already reeling. All this camtalk emphasizes the question, "Why would anyone focused only on light air subplaning sailing even want to fool with cambers, whose main contribution is stability in high winds?" More planing? Better wetsuit for more wintertime sailing. More fun in light air? Simplicity.

[konajoe]

OK Techno900, here's the deal. What we've been talking about in recent posts on this thread is that your statements for more and less downhaul are wrong. Changing only the downhaul won't change the fullness of the sail in the boom area when under load, because you haven't changed the distance between the leading edge of the mast and the loops in the outhaul lines. So, under a load, the clew grommet will be the same distance from the mast. So, your point 5. is also wrong.

The only one you got right is 6. For 3 and 4, outhaul has a big effect on fullness. Outhaul can also affect the leach quit a bit, depending on the amount of outhaul changes. Reducing outhaul makes the distance between the tip of the mast and the clew grommet shorter, which puts less tension on the trailing edge of the sail, and vice versa. You said you use adjustable outhaul. Have a friend hold up your rig like he's sailing on land. Stand where you can line up the clew grommet with the mast. Have the person 'sailing' the rig let out a bunch of outhaul. Notice how the trailing edge has moved farther away from the mast when looking from clew grommet to mast.

Aren't you one of the folks who never adjusts their downhaul?

[swchandler]

I have to say that I generally agree with techno900, particularly with rigging and unloaded sail on the beach. That said, what we really haven't been talking about is how the sail changes under dynamic load, and how that influences control and handling. When it comes to the downhaul/outhaul balance, I think that the folks that are on the lighter end of the scale tend to prefer a flatter foil and positive outhaul. The bias is for control. For folks on the heavier end of the scale, they usually prefer a fuller foil and negative outhaul. In this case the bias is for power.


"Aren't you one of the folks who never adjusts their downhaul?"


Konajoe, are you a heavier sailor?

[techno900]

joe, go to: http://www.bing.com/videos/search?q=race+sail+rigging&FORM=VIRE6#view=detail&mid=F3EE92B41BD696F35FB9F3EE92B41BD696F35FB9

Watch this and tell me I am wrong. Go to 4:50 and see the subtle flattening when finishing the downhaul, which Phil says is at the minimum. Then to 10:00 and watching closely as he let's off the downhaul while de-rigging - foil getting flatter? - I think not!

These sails don't change shape under dynamic load, except the twist in the upper/middle leach. Pretty much a fixed foil shape regardless of wind. I have been using these sails since Barry Spanier started his own loft 10 years ago.

Iso is right, these sails are not designed for light wind cruising, but there are cammed sails that do work well for light wind cruising. They have a clean foil shape in very light winds and don't need wind to "fill them in" to create an efficient foil.

[konajoe]

Techno900, please read this thread. I'm not sure why you're not.

I'm not EVEN going to look at the video you suggested. But let me guess: It shows a guy changing the downhaul with the no wind load on the rig.

We've all been agreeing (except you) that if you increase your downhaul with the booms attached, and the rig laying on the beach, you'll notice the outhaul line going slack. But, if you don't change the outhaul setting, the draft at the boom will be the same when sailing because the distance between the leading edge of the mast and the clew grommet hasn't changed.

[Gorge_R_and_D]

You guys are hilarious!

The guy is NOT planing! The best advice given so far is to get on a sail designed for sub planing.

Ittiandro, sell your other sails to fund this purchase. Suggestions have already been given here & on other forums about suitable sails. You may even be better off finding something old & vintage on E-bay around 6.5-7.5 with a tight leach.

Have fun!

[techno900]

I give up with Konajoe.

An example where technology and design maybe haven't made that much progress for light wind cruising is my 1985 Mistral Superlight and it's original triangle regatta sail. Dacron, light as a feather, three short leach battens and about 6.3 meters. The draft is moderately deep, and it takes almost no wind to fill it out into it's most efficient shape. I rig it on a 430 mast and a an old carbon formula long boom, which leaves a lot of sail down low near the water.

I have raced the rig numerous times over the last 30 years where the wind didn't show up at a regatta. While the Superlight hull is rounded and pretty efficient in light wind, the sail is amazingly efficient in winds under 10 mph. Obviously the shape isn't very stable, but it is fast (relatively speaking). I almost always am in front of 7, 8 & 9 meter sails on newer longboards.

The down side is that it has very little range. Once the wind kicks up some white caps (about 12 mph), the sail starts to become less and less stable (pocket moves around). Over 15-18 mph winds and it's not much fun. The board doesn't plane either, just plows ahead with the nose up so there is a lot of drag, so the sail becomes overpowered somewhat quickly.

[konajoe]