Telltale Rules

Sailing skills

Olympic coach Michael Blackburn offers advice on placement of these vital pieces of kit.

I once had a 30 minute argument over telltales.

Olympic coach Mike Fletcher is a passionate advocator of wool for this vital piece of kit, because it doesn't stick to the sail when wet and does a good job of flying as needed.

I much prefer spinnaker cloth cut into thin strips because it's more sensitive in light winds – when there is less feel in the boat and you need input from the telltales the most.

However, as Fletch argued, spinnaker cloth will stick to the sail when it's raining.

"Just spray a little McLube on the sail under the telltale," I would say.

"Anyway," I countered, "Wool gets too heavy when it's wet."

"At least it doesn’t stick to the sail," said Fletch. And on it went. ("Sheep stay out in the rain, you know...")

So in light winds and rain the options for telltales are the less sensitive wool or one that may stick to the sail (so don't go sailing in rain and light winds!).

At least we agreed on length and placement: I favour putting two 15cm long sets about 50-60 cm back from the luff and about 60cm up from the foot of a single-sailed boat. Put the starboard telltale an inch higher than the port one to help distinguish them in certain light conditions.

On a dinghy jib, put two sets about 15–30cm back from the luff (and further back as the sail gets bigger). As long as they are not too far back or too close to the luff it doesn't matter too much.

Why? Because the purpose of the telltales is to give you feedback on how the wind is flowing over the sail. Over time you will work out how they should be flowing to get the boat going fast. Remember that!

Then, when you get a new sail, put the tellies in exactly the same position. You will get used to seeing the telltales behave in a certain way when the boat is going well and be able to repeat that trim (assuming similar sail settings, especially luff tension).

Some people put tellies in the top third of their sails or leech and this can be good to indicate twist and angle of attack up there. For steering, however, it's good to use a set of tellies lower down too, so you can shift your gaze quickly between the water ahead and the sail without hurting your neck.

Some boats with jibs don't seem to bother with telltales on the mainsail. I think the more you know about the flow of air over the sails the better – after all, the sails are the only things aboard the boat that make it go forward!

Whether you have one upwind sail or two, it's more important to get the leeward telltale flowing than the windward one. This follows the basic trim guide: "If in doubt let it out" that encourages flow over the leeward side of the sails. Of course, it's also pretty good to have both telltales flowing (or the windward one breaking half the time), but bad to have just the leeward one breaking – it means you've stalled the sail.

On a run, you can largely ignore your telltales and use wind indicator(s) instead to show whether your air is being blocked by another boat and to help you follow gusts dead downwind.

Oh, if you do use the 3-ply wool, at least untwist the strands and just use one strand and you'll have a telltale which is 66% more sensitive!