Trimming jib down wind

[Slayer]

At what point of sail do you stop relying on telltales to trim the jib and rely on sail shape. I have read that on a down wind course the wind is pushing the sail rather than "lifting" it, and the tell tales are not a good indication of trim. Does this apply only when on a run, or also a broad reach? Or is it different with each boat?

[Sailormon6]

When the wind is no longer creating a laminar flow over the surface of the sails, aerodynamics is irrelevant, and the telltales are no longer helpful.

I have occasionally been able to keep the aerodynamic flow going until the boat was on a very broad reach, but the telltales stop working somewhere between a very broad reach and a run.

Also, in light air, there is a point when the wind is so light that it can no longer lift the weight of the telltales. At that time, the telltales become useless, and you have to resort to some other method of trimming the sails. Usually the best way is to ease the sail until it begins to lift at the leading edge (the luff), and then trim it back in a skosh, until it lays down.

[sailingfool]

Originally Posted by Slayer

At what point of sail do you stop relying on telltales to trim the jib and rely on sail shape. I have read that on a down wind course the wind is pushing the sail rather than "lifting" it, and the tell tales are not a good indication of trim. Does this apply only when on a run, or also a broad reach? Or is it different with each boat?

my experience is that lift disappears in the transition from a beam to a broad reach, as you can no longer ease the sails to maintain the necessary air flow. The telltales tell you that fact...

[nolatom]

Also, at some point on a deep broad reach, the jib becomes blanketed by the main to the extent that it's not doing too much anyway. The concept of 'perfect' jib trim at that point is more theoretical than real. That's why we have spinnakers, or head up a little to where the jib draws better.