What jib is best for very light winds

[cousineddy]

Forecast today is < 2 kts of wind. I am thinking that my giant 163% 3Di genoa will have a high windage to lift ratio compared to a dacron 105%, or even a lighter weight 140% upwind. Like, wind that light may not flow completely across the sail and exit cleanly. It would just be swirling half way back. Also, would need a much higher angle of attack than a jib, so pointing way lower. Is there any merit to this?

 

[dlochner]

In light air keeping the sail full is the challenge. Light air jib sheets and weight to leeward help. Otherwise I think the sail that has the best shape is the choice, probably the 3Di.

And if the RC tries to start a race in those conditions, they should be severely chastised at the club afterwards. The wind at the start will be so disturbed, no one will get off the line. Starting a race in under 5 kts is simply an exercise in frustration. I hope the SIs have a time limit.

 

[garymalmgren]

2 knots i not a lot of wind and nothing much could go wrong .
Stick em up and se what happens.
That is the only way you ill know.

 

[cousineddy]

Its redneck racing here. The race committee are also the racers. We do timed Bermuda starts which is pretty cool. Lots of racers drive from 2 hrs away. So, they don’t usually cancel races. Except when I am ahead, then they will. (My luck)

One of my previous boats (Evelyn 26) came with a drifter, but it was only 100%. I was like, whats this for? Didn’t have guts to use it in a race. Always used the largest genoa in light light conditions. But, it got me thinking now.

 

[dlochner]

Its redneck racing here. The race committee are also the racers. We do timed Bermuda starts which is pretty cool. Lots of racers drive from 2 hrs away. So, they don’t usually cancel races. Except when I am ahead, then they will. (My luck)

One of my previous boats (Evelyn 26) came with a drifter, but it was only 100%. I was like, whats this for? Didn’t have guts to use it in a race. Always used the largest genoa in light light conditions. But, it got me thinking now.

Interesting question. The Evelyn and the J30 are both fractional rigs, so the main driving force is the main sail. A smaller light sail might have a slight advantage going to weather allowing the boat to point up a degree or two.

What kind of course is being sailed? White sails only or Spinnaker. If the course is W-L or there is an off wind leg or two the larger 3Di will have a big advantage in a white sails race. You might lose a little upwind, but gain big down.

Shape, weight, sail and boat trim will be most important. In light air we would put crew below on the leeward bunks and keep make the crew lie down on the leeward rail to keep the slot clean. Reducing movement on the boat was essential, every move slow and easy so as to not disturb the air and water flow.

 

[cousineddy]

Im short on crew, either I am single handed, or have one helper. So, no spinnaker. But, the course is short enough that I am still competitive without the spinnaker. Depending on the wind direction, it can be W/L or triangle. We race on a river, even though it’s called a lake. Usually its W/L when the wind is straight down the river.

Off the wind, the mainsail is definitely dominant on this boat. Just not sure how dominant. There are two races. Maybe I use the 3Di in the first race, the 105 dacron in the second, if the race isnt called.

 

[dlochner]

There are two races. Maybe I use the 3Di in the first race, the 105 dacron in the second, if the race isnt called.

That will give you a couple of good datapoints. I'd be interested in hearing how it comes out.

 

[cousineddy]

Actual wind speed was 4-6 kts. The wind models were all wrong. So flew the 163% both races and did well. So, next time we get drifter conditions, I’ll try it. Happens alot around here.

 

[dlochner]

Actual wind speed was 4-6 kts. The wind models were all wrong. So flew the 163% both races and did well. So, next time we get drifter conditions, I’ll try it. Happens alot around here.

With winds that light, local conditions can vary quite a bit from the forecasts. Forecasts are most accurate when they are based on weather systems. In light air under a high pressure system it is a crapshoot.

 

[cousineddy]

It was cloudy with sprinkles. I bet those unexpected showers may have helped. It did drop to 0 kts a couple times. Fortunately, was between races.

 

[dlochner]

It was cloudy with sprinkles. I bet those unexpected showers may have helped. It did drop to 0 kts a couple times. Fortunately, was between races.

Probably, the rain cools some of the atmosphere and creates some convection currents, which brings on some wind. OK, so wind might be an over statement.

 

[shemandr]

Glad you did well but the 105 might have too. In very light wind a very flat sail will hold attached flow better than a deeper sail. In addition the smaller sail may allow better flow in the slot - better for up wind. 'Course downwind you'd want the 160 and probably some outboard sheeting - short sheet, whisker pole or reaching strut.
J30 is typically sailed with a crew of 5 or so. In super light wind 3 should be swimming behind the boat (Rules only say you have to finish with the crew you started with.). OK I'm kidding there. But at least they should be sitting over the keel, maybe in the cabin on more or less the lee side.

 

[Joe]

I'm in shemandr's camp with this. Smaller, flatter, lighter. My wire luff tall staysail (a sail intended for spinnaker augmentation) has worked quite well in conditions under 5 kts, especially when there are swells, since I'm in the ocean 95% of the time. I determined that its tall, narrow aspect and relatively flat cut combined with the lightweight cloth, allowed the sail to keep the breeze attached consistently. The detached luff helped as the AWD moves aft, rounding the sail a little more but not too much to loose flow. But the real deal is the 145 genny was just too much sail for light air, the 110 cloth weight was too heavy. I was struggling that day and pulled the staysail out because I had no more options. Steady quiet helm, no herky jerky moves, the air slowly evolves and the lifting increases. Cool.

 

[cousineddy]

J30 is typically sailed with a crew of 5 or so. In super light wind 3 should be swimming behind the boat (Rules only say you have to finish with the crew you started with.). OK I'm kidding there.

So I posted on the J30 website about this. J30 is notoriously blah in light air. The forums say put the crew forward and on the lee side. But swimming behind is the key. I have been doing well against a J100, J92 and other fancier race boats in the light stuff. I think low crew weight is why. But, I guess telling your crew to find another boat to sail on or go home is not cool at all. But, I’d probably be giving them the stink eye when we get passed. ( not really )