We all know what they're for, or do we? If you don't have telltales (on your sails), we urge you to get some. You can buy a set, or just tape some 6" pieces of yarn onto (each side) the jib, about a foot back from the luff.

Let's start with how we use the jib telltales. Going to weather, the leading edge of the jib, or the luff, should be splitting the apparent wind. (The apparent wind is the wind over the deck, a combination of the true wind and boat speed.) If so, then both telltales should be streaming horizontally. If the inside one flops around, you're pointed too high, and vice versa.

Having two or three sets of telltales spaced up the luff is helpful, especially on a reach, as they will show whether the luff is uniform. All the telltales should break together. If not, there may be too much twist in the sail. On a reach, the crew can apply a little down pressure on the sheet by hand to cure the "twisties".

Note that on a broad reach it's almost impossible to keep the inside telltale flowing smoothly. Don't worry about it, the outside one is the more important one, and it must be kept streaming.. If you can't, maybe you're headed too far off the wind, and should set the pole. Downwind, while wing and wing, the telltales are useless, and should be ignored.

You should have a single telltale on the leech of the mainsail, at the top batten. This tells you whether the main is "breathing". If it hangs down, you're probably over-sheeted. I like to let out the main just enough to fly the telltale, but not so far as to make the main luff, although a little bit of backwinding is okay. It's better to have the main too far out than too far in. One of the most common mistakes for beginners is to oversheet, especially in light air.