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Old 08-11-2013, 10:55   #1
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Light Air Sailing?

Some texts I read recommend powering up by easing the luff and outhaul thereby creating more draft when sailing upwind. Others recommend flattening the sails to reduce drag.

Which have you found to be more successful when sailing in lighter air up to 7kts?
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Old 08-11-2013, 11:08   #2
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Unless the boat is an ultralight or a light multi I would ease the downhaul and the jib halyard to get more draft. With these adjustments you would need to sail a bit lower when pointing but will make up for the extra distance by sailing faster.
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Old 08-11-2013, 11:11   #3
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Re: light air sailing?

You want more shape to the sail, not flatter. Ease the luff and outhaul a bit. ease the sheet until it luff then bring it back in just a touch.
Flattening the sails does work well, just start up the "iron reacher" and flatten the main!
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Old 08-11-2013, 11:30   #4
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Re: light air sailing?

Cruisers don't know how or won't bother because most heavy boats with smaller sail areas simply don't sail well, if at all in really light winds but whoever told you to flatten the sails in "really" light air is correct. That said in normal light air then you will want a deeper draft and you can do this by reducing the halyard tension and putting little speed wrinkles in your sails.
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Old 08-11-2013, 11:42   #5
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Re: light air sailing?

7kn is not light air... Try racing in 1kn as measured.

In steady light air of 2-3kn then a deep draft sail is going to generate more power. On those days when the air is still, and just every now and then you feel a touch of movement board flat sails with tight everything can generate power where a deeper sail won't even fill with the available wind.

Frankly, unless you a re racing there is no reason to even try to sail in these conditions, and the best thing to do is just turn on the motor. If racing, well we carry a 1kn drifter, which is a super flat cut 105% (compared to our light air 155%) made from .25oz nylon. It will explode in 5kn steady breaze, but the small sail plus light cloth plus flat cut allows us to keep moving (if barely) on almost dead still days.
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Old 08-11-2013, 11:48   #6
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Re: light air sailing?

The sail is like the wing on an a commercial jet. For slow speeds/light winds, you want it with lots of fullness/curvature for maximum lift/driving force. Drag isn't a big concern because of the low airspeed over the sail. The lift to generate forward momentum out weighs the drag created. An aircraft wing is designed with slats and flaps to increase the curve and the resulting lift for low speed work. You accomplish this with a sail by easing the sheet, outhaul and halyard.
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Old 08-11-2013, 13:04   #7
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Re: light air sailing?

under 10 kts is light air for my boat!!!! up to 10 kts we drift, over 10 kts winds we sail somewhat...
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Old 08-11-2013, 13:14   #8
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Re: light air sailing?

Quote:
Originally Posted by Stumble View Post
7kn is not light air... Try racing in 1kn as measured.

Frankly, unless you a re racing there is no reason to even try to sail in these conditions, and the best thing to do is just turn on the motor. If racing, well we carry a 1kn drifter, which is a super flat cut 105% (compared to our light air 155%) made from .25oz nylon. It will explode in 5kn steady breaze, but the small sail plus light cloth plus flat cut allows us to keep moving (if barely) on almost dead still days.
Actually we are racing and the wind is light around here this time of year (November-December) and given we race club boats without much help in the way of good sails or inventory, or the opportunity to go out and really get to know a particular boat, any suggestions are appreciated.

Races don't usually get underway if there isn't at least 3 knts of wind but we're not expecting more than 5-6 tops.
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Old 11-11-2013, 15:37   #9
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Re: Light Air Sailing?

Lower the bimini.

Understand convection heating. From land, to water, from water to land. Cloud shadows also apply.

Read about where the downdraft is on cloud lines, you can sail under them in a 50 yard wide area on one side of them... on most windless days. The cold air falls down to the ground off of them on one side and warm air rises on the other side.

It helps to know which way the pressure zone you are in, is rotating. Very seldom are they totally still... You should have a morning shift and afternoon shift, based on convection heating of the high or low pressure zone within its boundaries.

As far as the boat goes:

Downsize your jib sheets to as small as you can hold onto. Cow hitch them, do away with the snap shackle.

Put up the largest sail that will stay set for that point of sail. If you have a paper thin 100% working jib, you might find that is your best light air sail into the wind. I have never understood why the 180% Genoas need to be stiff as a board laminated carbon, that takes a lot of wind for them to set. If it won't stay set, try going down a size instead of up.

Try to lash the helm on centerline. 5 degrees of rudder angle is enough that you may as well be going backwards. Steer by moving weight around on the boat, and sail trim. Not your rudder. If you steer with your rudder, you'll go down wind with the sails set but you won't be making any speed.

Hold onto your lines by hand, ease them when the pressure starts to drop. Bring them in when it starts to pick up, until the pressure starts to drop.

Use your topping lift to pick up the boom if you are in very light airs, the weight of the boom pulls the sail flat midway through the head. You want it baggy, even with a touch of twist, if you suspect there is wind sheer between your ears and the windicator.

Also a barberhaul on the boom to hold it down if you have a bit of leftover swell coming around can be helpful. If it is luffing on each roll and heave, holding it down can keep it set a bit better. Combined with the topping lift you can make the sail shape about whatever you want it. Telltails in the front third of the sail can help quite a bit.

Cassette tape works very well as telltail material when there is no wind to speak of.

It will tell you when your boat speed is approaching wind speed, and when you need to start sheeting in because boat speed is the apparent wind direction. You can't run the speed of the wind until you start sheeting in accounting your boat speed, or start coming on to a reach.

Heel the boat to leeward, if possible. Also if you have a strap on the tack to see under it, try taking it out and getting the jib or genoa down as close to the deck as you can. You increase the efficiency with deck sweepers.

If you are bored... If you have a wire or fancy rope luff on your jib, you can try flying it free as a poor mans blooper in tandem to your spinnaker.

Zach
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Old 12-11-2013, 17:29   #10
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Re: Light Air Sailing?

Over the last 50-60 years summer cursing East and West coast when the wind is less than 10k about 98% of sailboats have a motor running with or without sail. Unless you are racing or are without motor or fuel tiring to get a heavy under sailed cruising boat moving in light air is wasted effort. On my light high performance sloop or on my previous tri I could and do sail in light stuff. I do ease the sails and head off until I build some speed then I experiment with flattening sail and if beating come up.
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Old 13-11-2013, 19:44   #11
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Quote:
Originally Posted by Zach View Post
Lower the bimini. Understand convection heating. From land, to water, from water to land. Cloud shadows also apply. Read about where the downdraft is on cloud lines, you can sail under them in a 50 yard wide area on one side of them... on most windless days. The cold air falls down to the ground off of them on one side and warm air rises on the other side. It helps to know which way the pressure zone you are in, is rotating. Very seldom are they totally still... You should have a morning shift and afternoon shift, based on convection heating of the high or low pressure zone within its boundaries. As far as the boat goes: Downsize your jib sheets to as small as you can hold onto. Cow hitch them, do away with the snap shackle. Put up the largest sail that will stay set for that point of sail. If you have a paper thin 100% working jib, you might find that is your best light air sail into the wind. I have never understood why the 180% Genoas need to be stiff as a board laminated carbon, that takes a lot of wind for them to set. If it won't stay set, try going down a size instead of up. Try to lash the helm on centerline. 5 degrees of rudder angle is enough that you may as well be going backwards. Steer by moving weight around on the boat, and sail trim. Not your rudder. If you steer with your rudder, you'll go down wind with the sails set but you won't be making any speed. Hold onto your lines by hand, ease them when the pressure starts to drop. Bring them in when it starts to pick up, until the pressure starts to drop. Use your topping lift to pick up the boom if you are in very light airs, the weight of the boom pulls the sail flat midway through the head. You want it baggy, even with a touch of twist, if you suspect there is wind sheer between your ears and the windicator. Also a barberhaul on the boom to hold it down if you have a bit of leftover swell coming around can be helpful. If it is luffing on each roll and heave, holding it down can keep it set a bit better. Combined with the topping lift you can make the sail shape about whatever you want it. Telltails in the front third of the sail can help quite a bit. Cassette tape works very well as telltail material when there is no wind to speak of. It will tell you when your boat speed is approaching wind speed, and when you need to start sheeting in because boat speed is the apparent wind direction. You can't run the speed of the wind until you start sheeting in accounting your boat speed, or start coming on to a reach. Heel the boat to leeward, if possible. Also if you have a strap on the tack to see under it, try taking it out and getting the jib or genoa down as close to the deck as you can. You increase the efficiency with deck sweepers. If you are bored... If you have a wire or fancy rope luff on your jib, you can try flying it free as a poor mans blooper in tandem to your spinnaker. Zach
Excellent points, I highly concur.

If your sailing coastal, yes the motor works. In the doldrums, or other dead zones, it isn't an option.

Jeff
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Old 13-11-2013, 19:55   #12
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Excellent points, I highly concur. If your sailing coastal, yes the motor works. In the doldrums, or other dead zones, it isn't an option. Jeff
Why? You take the prop off when you sail through the doldrums? Almost everybody uses the engine to get through the doldrums.
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Old 13-11-2013, 21:15   #13
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Everyone is correct in mildly light air, fuller = better. Ultra light air fuller = stall. To continue the airplane with flaps analogy, once the airflow becomes too slow it plummets into the ground (plummets!!, not just can't maintain altitude, which in sailing terms would mean goes slower). If the flow can't stay connected to the sail then it becomes useless. An ultra light smallish flat jib (or staysail) in racing jargon - wind seeker, is often the only choice. Not racing, just put away the annoying flogging sail and wait, if engine not possible, or turn on the engine if patience runs out.
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Old 14-11-2013, 11:11   #14
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Re: Light Air Sailing?

Quote:
Originally Posted by Zach View Post
Lower the bimini.

Understand convection heating. From land, to water, from water to land. Cloud shadows also apply.

Read about where the downdraft is on cloud lines, you can sail under them in a 50 yard wide area on one side of them... on most windless days. The cold air falls down to the ground off of them on one side and warm air rises on the other side.

It helps to know which way the pressure zone you are in, is rotating. Very seldom are they totally still... You should have a morning shift and afternoon shift, based on convection heating of the high or low pressure zone within its boundaries.

As far as the boat goes:

Downsize your jib sheets to as small as you can hold onto. Cow hitch them, do away with the snap shackle.

Put up the largest sail that will stay set for that point of sail. If you have a paper thin 100% working jib, you might find that is your best light air sail into the wind. I have never understood why the 180% Genoas need to be stiff as a board laminated carbon, that takes a lot of wind for them to set. If it won't stay set, try going down a size instead of up.

Try to lash the helm on centerline. 5 degrees of rudder angle is enough that you may as well be going backwards. Steer by moving weight around on the boat, and sail trim. Not your rudder. If you steer with your rudder, you'll go down wind with the sails set but you won't be making any speed.

Hold onto your lines by hand, ease them when the pressure starts to drop. Bring them in when it starts to pick up, until the pressure starts to drop.

Use your topping lift to pick up the boom if you are in very light airs, the weight of the boom pulls the sail flat midway through the head. You want it baggy, even with a touch of twist, if you suspect there is wind sheer between your ears and the windicator.

Also a barberhaul on the boom to hold it down if you have a bit of leftover swell coming around can be helpful. If it is luffing on each roll and heave, holding it down can keep it set a bit better. Combined with the topping lift you can make the sail shape about whatever you want it. Telltails in the front third of the sail can help quite a bit.

Cassette tape works very well as telltail material when there is no wind to speak of.

It will tell you when your boat speed is approaching wind speed, and when you need to start sheeting in because boat speed is the apparent wind direction. You can't run the speed of the wind until you start sheeting in accounting your boat speed, or start coming on to a reach.

Heel the boat to leeward, if possible. Also if you have a strap on the tack to see under it, try taking it out and getting the jib or genoa down as close to the deck as you can. You increase the efficiency with deck sweepers.

If you are bored... If you have a wire or fancy rope luff on your jib, you can try flying it free as a poor mans blooper in tandem to your spinnaker.

Zach
All really good ideas and have tried them all while racing in light summer air.
If you have weight to move around and are bored shift it to the downwind side, if the boat has a little heal going on the sails will basically hang in a foil shape and really take advantage of the extra shape you've already produced by loosening things up. When racing I've used crew to do that, of course I've also had to wake them up from napping on the rail to shift during a tack on a long, light wind race.
Holding the sail by hand is a neat trick when racing, even on the 38 or 40 foot boat but i'm not sure you'd want to do that for long periods when cruising, unless of course you had a beer in the other hand.
Is that a new definition for "feel the wind"?
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Old 14-11-2013, 14:00   #15
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Re: Light Air Sailing?

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Why? You take the prop off when you sail through the doldrums? Almost everybody uses the engine to get through the doldrums.
Jedi, not everybody.... Depends on how the ITCZ is as you approach; one time we sailed the whole way. Another, we motored some. Crossing the ITCZ is like lots of other deals sailing, it all depends on the conditions when you get there. But I'll bet you're right, most people are adequately goal-oriented these days, and carry enough fuel, and don't care too much about the costs, and I'd not be surprised if they all motored. I'll also bet that if you expect to motor, you're more likely to motor than someone who sets out to sail it. [Expectations and experiences interact.]

Ann
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