Move the sail towards the telltale that isn’t streaming: if the windward one lifts, pull the sheet in; if the leeward one droops, let it out. When close-hauled, with the jib already in tight, steer instead: bear away if the windward one lifts, head up if the leeward one droops.
The rule for jib telltales is to move the sail towards the side whose telltale isn’t streaming.
- Windward telltale lifting: the sail is too far out. Pull the sheet in until it streams.
- Leeward telltale drooping: the sail is too far in and has stalled. Ease the sheet until it streams.
- Both streaming: leave it.
If you are not sure where the sail should be, ease the sheet until the windward telltale just starts to lift, then pull it back in a little. That is where the sail works best. The over-trimmed jib is the commoner mistake, because a sail pulled in too tight still looks full and powerful, and the boat may even heel more, but she is slower.
Close-hauled, the jib is already pulled right in and can’t be trimmed any further, so you steer by the telltales instead:
- Windward one lifting: you are too close to the wind. Bear away slightly.
- Leeward one drooping: you have turned too far away. Head up slightly.
Small, gentle movements of the tiller or wheel are all it takes. Watch the telltales and the water ahead, and respond before the boat slows down.
The pairs at different heights also tell you about the jib’s twist. Ideally all the pairs break at about the same time as you head up. If the top windward telltale lifts well before the lower ones, the top of the sail is too open: move the jib sheet car forward. If the lower ones lift first, move the car aft. On boats without adjustable cars, trim for the middle pair.
The wind shifts and changes strength all the time, so a good crew keeps the jib sheet in hand and watches the telltales continuously.
More in the book: Chapter 5, Trimming the sails