Sail trimming is a vital skill as you learn to sail or improve speed performance of your boat. Telltales can be very useful, low-tech tools to overcome wind’s invisibility that makes it tricky to determine if your sails are trimmed properly.
Telltales are not required and some say it is better to learn to sail without them, but those who take racing seriously are usually big fans of these small helpers.
The main benefit of using telltales instead of watching for the sail to flap is that they are more sensitive.
Telltales can:
- Tell you how wind is flowing over the sail
- Tell you when wind shifts
- Tell you if you can sail higher or if you are pinching too much
- Tell you if you are over- or under-sheeted or well-adjusted
- Tell you if your sail twist is correct
- Tell you how much kicker to have on off-the-wind
How Telltales Work
Telltales are loose lengths of nylon, yarn, or sailcloth attached near the luff of the sail. The telltales should be in contrasting colors to your sails so their movement is easily seen. Their purpose is to help you visually detect wind flow around the sails so that you can know how to adjust your sails or be confident they are well-trimmed.
What to Do About Telltale Movements
If both telltales stream straight back, it means the wind is flowing smoothly over both sides of the sail.
If the windward telltale (the one closest to side the wind is coming from) is fluttering, either sheet in (pull in) the jib toward the telltale OR or bear away (turn the boat away) from the telltale until it streams straight back indicating wind is flowing smoothly.
If the leeward telltale (the one farthest away from the wind’s direction) is fluttering, ease the sail toward the telltale OR bear away (turn the boat away) from the telltale until it streams straight back indicating wind is flowing smoothly.
