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Old 18-12-2015, 07:12   #76
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Re: Going hard to wind, main sail trim.

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Originally Posted by ozskipper View Post
Its inefficiency by having a lump of rolled sail on the leading edge is what I am talking about.
Like I said, decreasing performance was the reason to roll up the jib some.

As for the lump of rolled up sail, it really doesn't matter if you are wanting to sail slower and closer to the wind (if the reason is simply to get to his mooring)

Some racers on boats with rotating masts many times will over rotate to depower. The over rotation breaks up the air flow over the main allowing the boat to sail closer to the wind

In lighter air, you rotate properly so the mast appears to be a part of the sail......for clean air flow over the main

Mast rotation and prebend:

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Old 18-12-2015, 09:28   #77
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Re: Going hard to wind, main sail trim.

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Originally Posted by OldFrog75 View Post
Is "downhaul" synonymous with Foreguy and/or Cunningham or is it something different?
Not really synonymous, though any of the following may be used to increase luff tension.

Mainsail Downhaul. Usually connected to sliding boom goose neck. Primary purpose is to set the main sail tack height at the lower black band on mast.

Mainsail Halyard. Connected to main sail head. Primary purpose is to raise the main sail head to the upper black band on mast.

Cunningham. Connected to cringle above mainsail tack. Primary purpose is to ease luff tension downwind and increase luff tension up wind, to maximize effective sail area, without going outside black bands (main sail max luff dimension).

When a downhaul (or halyard) is used to increase luff tension, it could pull the luff beyond the black bands, disqualifying a racer.

When a Cunningham is used to increase luff tension, the luff remains within the black bands. Additionally, the main sail leach is looser (more open).
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Old 18-12-2015, 10:16   #78
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Re: Going hard to wind, main sail trim.

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Originally Posted by ramblinrod View Post
Not really synonymous, though any of the following may be used to increase luff tension.

Mainsail Downhaul. Usually connected to sliding boom goose neck. Primary purpose is to set the main sail tack height at the lower black band on mast.
.
Thanks for that. So technically a downhaul is a different piece of equipment than a cunningham. Now that you mention it, I remember reading that somewhere or seeing a picture; just never seen a boat rigged that way so I forgot about it.

So confusion arises when people refer to the cunningham (or foreguy) as a downhaul, although I think perhaps downhaul is sometimes defined and used generically to mean any control that puts pressure on the luff of a sail by pulling the bottom lower.
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Old 18-12-2015, 15:55   #79
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Re: Going hard to wind, main sail trim.

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Originally Posted by monte View Post
Sailing to windward, what's that?
Motoring?
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Old 18-12-2015, 16:37   #80
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Re: Going hard to wind, main sail trim.

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Motoring?
Good point.

(But) Upwind sailing though especially when another evenly matched boat is involved does make you think



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Old 18-12-2015, 20:42   #81
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Re: Going hard to wind, main sail trim.

[QUOTE=OldFrog75;1990962]
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Originally Posted by ozskipper View Post

I think you mean CE forward but I understand what you're saying. We're both waiting for the answer.

Oops. Yeh typo. The CLR will be aft of the new CE.
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Old 18-12-2015, 20:49   #82
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Re: Going hard to wind, main sail trim.

[QUOTE=thomm225;1990975]Like I said, decreasing performance was the reason to roll up the jib some.

As for the lump of rolled up sail, it really doesn't matter if you are wanting to sail slower and closer to the wind (if the reason is simply to get to his mooring)

Some racers on boats with rotating masts many times will over rotate to depower. The over rotation breaks up the air flow over the main allowing the boat to sail closer to the wind

In lighter air, you rotate properly so the mast appears to be a part of the sail......for clean air flow over the main

End Quote__________________________________-

Yes, I grew up racing boats with Rotating masts. They provide various inefficiencies in varied conditions. A partly furled genoa with a baggy luff wont do anything like a rotating mast. As the main on a rotating mast is still in shape. A partly furled sail isnt in shape, thats why its the last choice when looking for efficiency.
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Old 18-12-2015, 23:20   #83
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Re: Going hard to wind, main sail trim.

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Originally Posted by ozskipper View Post
Yes, I grew up racing boats with Rotating masts. They provide various inefficiencies in varied conditions. A partly furled genoa with a baggy luff wont do anything like a rotating mast. As the main on a rotating mast is still in shape. A partly furled sail isnt in shape, thats why its the last choice when looking for efficiency.
Yeah… I really doubt a bagged out, part rolled headsail is going to get anyone closer to the wind, or make pinching up any easier. Pretty much the opposite actually. Rotating mast is a completely different proposition.
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Old 19-12-2015, 05:05   #84
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Re: Going hard to wind, main sail trim.

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Originally Posted by ozskipper View Post
A partly furled genoa with a baggy luff wont do anything like a rotating mast. As the main on a rotating mast is still in shape. A partly furled sail isnt in shape, thats why its the last choice when looking for efficiency.
Now you are mixing the two things up to try and prove your point. It happens a lot here.

The point in the first example was depowering by decreasing jib size (decreasing it's efficiency) and flattening the main etc to point up to the mooring.

The rotating mast example was simply a way of showing how racers sometimes depower by overrotating the fat part of the mast directly into the wind which slows things down (depowers the main) to allow the boat to point higher

In lighter winds, you rotate the mast for good smooth airflow over the main as if it is a part of the sail

I raced boats with rotating masts for around 15 years. We could rotate our masts, adjust downhaul, mainsheet tension, and traveler position all from the trapeze.

Between races we could make changes to the prebend if necessary while out on the water.


Speaking of racing: (this is a pretty awesome prestart and first leg upwind)


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Old 19-12-2015, 06:23   #85
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Re: Going hard to wind, main sail trim.

[QUOTE=thomm225;1991790]Now you are mixing the two things up to try and prove your point. It happens a lot here.

The point in the first example was depowering by decreasing jib size (decreasing it's efficiency) and flattening the main etc to point up to the mooring.

The rotating mast example was simply a way of showing how racers sometimes depower by overrotating the fat part of the mast directly into the wind which slows things down (depowers the main) to allow the boat to point higher

In lighter winds, you rotate the mast for good smooth airflow over the main as if it is a part of the sail

I raced boats with rotating masts for around 15 years. We could rotate our masts, adjust downhaul, mainsheet tension, and traveler position all from the trapeze.

Between races we could make changes to the prebend if necessary while out on the water.


Speaking of racing: (this is a pretty awesome prestart and first leg upwind)

End Quote.

But the OP doesnt want to reduce performance.
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Old 19-12-2015, 06:25   #86
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Re: Going hard to wind, main sail trim.

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=ozskipper;1991827
But the OP doesnt want to reduce performance.
Sure he does, he's trying to point into 20 knot winds.

That's why he was flattening the main etc to reduce it's power.

Or as others have pointed out reefing the main which is definitely reducing performance
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Old 19-12-2015, 06:43   #87
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Re: Going hard to wind, main sail trim.

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Originally Posted by thomm225 View Post
Sure he does, he's trying to point into 20 knot winds.

That's why he was flattening the main etc to reduce it's power.

Or as others have pointed out reefing the main which is definitely reducing performance
Flattening sail does not reduce performance in heavy winds. It increases it!
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Old 19-12-2015, 07:02   #88
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Re: Going hard to wind, main sail trim.

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Originally Posted by ozskipper View Post
Flattening sail does not reduce performance in heavy winds. It increases it!
Now you are playing word games. Okay!

You flatten the mainsail to depower which reduces it's efficiency while give the boat better upwind performance toward the mark.
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Old 19-12-2015, 07:56   #89
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Re: Going hard to wind, main sail trim.

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Originally Posted by MollyJo View Post
Hi All
Returning to my mooring, the last 3 nm's is always hard to wind in 20 kts. My boat is 30ft, 3.5 tone sloop. She travels well to wind but I wonder if I could be doing better. The set up....., pointing as high as possible, some minor back winding in the top third of the main, traveller hard to windward, main sheet hard on, vang firm, out haul hard, down haul hard, very healed over, ie gunnel awash, and more weather helm than desirable but making 6 knots in the right direction. Occasional uncontrolled rounding up in big gusts. If I ease the main and hold the course it begins to flog. If I dump the traveller, same thing.
Should I drop a few degrees off the wind and add a tack later or stay close hauled? Is there a better way to set the sail when sailing as close as you can go to windward? I have to say I'm pretty happy with 6 knts but the rig is pretty loaded up and the first mate is a little uncomfortable with the heal but getting better all the time. Thanks for your thoughts


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Heeled hard over and, especially, "uncontrolled rounding up" (!), means you are way overpressed and definitely sailing slower than you could be, and with more effort and risk.

The degree of heel which would be right under the circumstances depends on your boat -- certain hull shapes tolerate it better than others and only you can know. Modern hulls with higher aspect keels tend to hate it. My boat starts to sail badly -- weather helm, leeway, etc. -- after only 20 degrees, and I have to reef if I can't get the heel under that by other means. But my old boat with a longer keel liked heel up to about 30 degrees, so it really depends on the boat.

Others have told you to take in a reef. Maybe. Probably.

But there are a few things to think about before reefing.

I'm assuming you've got the headsail trimmed right -- you didn't ask about that. Is it oversheeted? Is the sheeting position right? Can you get the sheeting position further inboard? My boat benefits from barber-hauling the headsail sheet inboard, when hard on the wind.

When you turn your attention to the main, first of all, this should be shaped right, and then, it should be pointed in the right direction. By 20 knots, my own boat will not require reefing quite yet, but the main must be flattened into a lower-drag shape. I don't know what kind of condition your sail is in, but if it's old and baggy, you might not be able to achieve such a shape, and in that case, then you will need to reef earlier. If you have a good sail, you will be able to flatten it to the point where it starts to lose power ("put it to sleep"), and you can play with it to find the optimum deepness, not "put to sleep", still making power, but with minimum drag. This is more and more important, the stronger the wind. Then when you have the right shape, you have to start thinking about the right angle of attack ("point it in the right direction") with the traveler. Every boat is different, but I have never seen a boat that wanted the traveler hard awindward in 20 knots of wind. On my boat in those conditions, the traveler will likely be let down a bit leeward of center, and will get let down all the way in the gusts. If you have an overlapping headsail, then a little backwinding of the luff of the mainsail is inevitable and is not really a problem, but you should adjust the angle of attack so that the air stream gets reattached and flowing smoothly not to far aft of the mast. If you have trouble with that, then the headsail may be oversheeted. Do not, however, just put the traveler up until the bubble disappears. That would be the wrong angle for the main part of the mainsail, just for the sake of getting air onto the luff. Too high an angle of attack will produce extra weather helm and extra heeling.

You asked whether you're pointing too high. This is a key question. The easiest way to answer it is to get the sails trimmed right, then calculate VMG to windward at different angles. The right angle is the one which gives you max VMG to windward. Different boats, and different sails, are very different. With my old baggy sails, I needed to crack well off -- about 37 AWA was optimum for the conditions you describe.

The reason for that is this -- pointing is a battle of lift versus drag, and baggy sails will have a lot of drag you just can't get rid of. The drag will slow you down, then kill you with leeway, because of a vicious combination of two factors -- first of all, the drag vector of the forces on your rig sets you off to leeward, and second, the less speed you have, the more a given rate of being set off to leeward, opens up the angle between heading and COG, which is the definition of leeway. So you need speed at all costs and you crack off. I found that with my old baggy sails, it paid not to overtrim them, but allow them to have a bit of shape and concentrate on speed. Optimum VMG to windward, with my old sails, was not far from the angle at which I had optimum boat speed. Very different with my new sails. YMMV.

With better sails, you can get up closer and you can even afford to go a bit slower, but closer to the wind. With my new sails (carbon laminate) it's about 28 degrees in the conditions you describe, assuming sea conditions are reasonably mild; more if it's choppy. Boat speed at optimum VMG to windward, with my new sails, is fully a couple of knots below best boat speed when cracked off even just a bit, say 40 AWA. At 40 AWA in 20 knots I can reliably do hull speed (9.5 knots); at 28 this will go down to 7.5 or so, but I'm making more VMG to windward. I will be tacking in about 100 degrees over ground, maybe 95 on a really good day.

The real obvious sign of pinching is when leeway spikes up. On some boats, with some sails, leeway goes up so fast that COG even starts to go backwards, and surprisingly early. But contrary to the case of leeway, you can't say for sure you're pinching, just because you are losing speed. Some boats are still gaining VMG to windward even as speed has fallen well off. Other boats not. You have to experiment.


Good luck and let us know how you get on. Sail trim upwind is a bit of a black art, with enough variables to make it incredibly complicated (which also makes it fun). I am still fumbling around with it, but getting slightly better every year.
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Old 19-12-2015, 08:06   #90
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Re: Going hard to wind, main sail trim.

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Originally Posted by Muckle Flugga View Post
Yeah… I really doubt a bagged out, part rolled headsail is going to get anyone closer to the wind, or make pinching up any easier. Pretty much the opposite actually. Rotating mast is a completely different proposition.
Amen! What racing boats do, is often not translatable to what we do.

I reef main first, and only in desperate situations do I reef the headsail. I have a blade jib which can be put up instead of the yankee, if there are enough strong bodies on board to do it.

It's better with new sails, but even with them, you can pretty much forget making a lot of progress upwind, once you start to reef the headsail.

Not applicable to the OP, but if you have in-mast furling, like I do, reefing the main has little effect on its shape (someone might say it's just as crappy reefed, as it is not ). The main drawback of the reefed main when hard on the wind is that you lose a disproportionate amount of drive, because the part of the main which is in clean air is the part out closest to the backstay (same reason why roach is so important). So you might roll it in by only 25%, and lose 50% of the drive from the mainsail.

This is not really tragic because by the time you get to wind strong enough to require that, the unreefed headsail is already providing as much power as your boat can use. Let the headsail have its way -- the headsail is the real engine of a cruising rig. My boat actually sails pretty well upwind with the mainsail completely put away.
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