Tell tails on a run.

[zz4gta]

When heading downwind at different angles what should the tell tails look like? I was out a bit ago and they were swept forward, pointing toward the mast on a broad run.

Should I let main out more to be more perpendicular to the wind? Should I even pay attention to the tell tails on a broad or dead run?

[Stryker72]

Originally Posted by zz4gta

When heading downwind at different angles what should the tell tails look like? I was out a bit ago and they were swept forward, pointing toward the mast on a broad run.

Should I let main out more to be more perpendicular to the wind? Should I even pay attention to the tell tails on a broad or dead run?

I have been on some boats that had a tell tale on the backstay. I found that to be helpful on any thing greater than a beam reach.

[RichH]

For the sail to be acting like a wing and with good aerodynamic efficiency .... all the tell tales should be streaming 'straight back' on a sail.

Once the tell tales 'go forward' you lose most of the sails aerodynamic efficiency due to stalling etc. of the sail .... the only 'thing' then driving the sail then is 'drag'. Once the sail is being driven solely by 'drag', all you need to do is get the sail 'square' to the wind so that the sail presents the largest cross-section to the wind .... ie.: the boom about 90 degrees to the wind.

By all means if you want to go FAST pull-in the sheets and sail a HIGHER angle downwind. By sailing HIGHER than DDW, the apparent wind will be higher which will allow you to sail FASTER and by sailing FASTER the apparent wind will go FORWARD, etc.
:-)

[sailingdog]

Originally Posted by RichH

By all means if you want to go FAST pull-in the sheets and sail a HIGHER angle downwind. By sailing HIGHER than DDW, the apparent wind will be higher which will allow you to sail FASTER and by sailing FASTER the apparent wind will go FORWARD, etc.
:-)

Of course this works better on some boats, like Multihulls, than others...

[tenuki]

depending on the boat you have north sails usually has amazingly good tips on sail shape.

[RichH]

The faster the boat the better effect in 'tacking' downwind. Tacking downwind wherein the sails are ALWAYS 'flying' under full aerodynamic conditions.

All this was most likely a 'borrow' from the ice-boat fleets in the upper midwestern US where an iceboat going so fast (almost) dead downwind had the tales flying straight back (and sails pulled in tight). Since the upper midwest was also home to the ultrafast sailing ILYA **SCOWs** (Buddy Melges, et al) the practice became 'standard' with soft-water sailors ... and moved on from there. .... ultimately and probably leading to the decline of 'triangular' race courses and the adoption of simple windward-leeward courses.

[Sailormon6]

Generally, on a dead run, or almost a dead run, the telltales on the sail mean virtually nothing. The wind isn't moving across both surfaces of the sail in a laminar flow. It's just pushing on one surface of the sail, driving the boat downwind like a leaf on a pond. As you steer the boat increasingly upwind, from a run to a broad reach to a beam reach, at some point, the wind begins to flow across both sides of the sail in a laminar flow. I can't describe exactly at what point that happens, because it depends somewhat on how your boat is rigged and how you sail it, but when it happens, then the telltales on your sails start to lift and can be used to help you trim your sails again.

[saurav16]

Sorry don't mean to high jack the post but on a down wind run or a broad reach what should the traveller setting be?

[RichH]

Good question and really applies to the subject.

Traveller is set (up or down) depending on how much twist is needed in the mainsail. How to assay? .... If not 'drag sailing' but sailing an angle high enough so that you are getting FLOW accross the sail, look at the telltells especially on the leech. The aim is to get ALL the leech telltales evenlyh flying straight back.

With the traveller set on the centerline, usually the boom is setting too high with the result that the top sections of the sail are stalling, etc. ... as will be seen by the topmost leech telltales being VERY agitated or pointing forwards on the leeside of the sails leech. On such a deep reach and in light to moderate winds the proper setting of (leech, etc.) telltales is accomplished by traveller posiition and sometimes includes tensioning the boom topping lift, etc. No guess work, just look at the telltales (and the speedo). :-)

[Giulietta]

In a dead downwind the apparent wind might be 0 zero, causing the tell tales to do anything.

See photo bellow, look at stbd shroud, there is a wind tell tale there, its dead down, yet we were doing 5 knots boat speed.