Reaching 90-115 degrees
If pole height is important when running and broad reaching, it is critical when reaching as it changes the shape of the sail both vertically and horizontally. The airstream is attached, and telltales can be very useful to indicate the optimum height. In fact, when reaching, telltales mean the trimmer does not have to curl the luff to determine
the correct trim, which keeps the projected area as high as possible so therefore faster.
If the pole is too high, the bottom telltale breaks first, as will the lower luff break also. As the pole goes up it changes the horizontal shape by allowing the leeches to spread apart, and the sail becomes flatter.
If the pole is too low, the top telltale breaks first, as will the upper luff break first also. As the pole goes up it changes the horizontal shape by allowing the leeches to come together, and the sail becomes fuller.
Lowering the pole also tensions the luff – and makes the luff more stable since the luff curl is progressive and easily controlled. On a really tight reach, lifting the pole can flatten the sail enough for you to get there, but…….the trimmer will have no ability to stop the curl easily and the spinnaker may collapse completely. The sail will be
overtrimmed and be heeling the boat a lot. This works mainly in light winds, and in heavier winds the chance of a broach is very high – the genoa or on a jib-boat, a Code 0, may be a better option.
Unlike running and broad reaching, the pole should be over squared by about 10 to 15 degrees. (It is actually the same rules concerning the vertical seam – it will be vertical, but it is now very difficult to see). An oversquared pole, set low, with the tweaker off, and the sheet position well aft is the best way to trim a spinnaker in heavy airs. In this set-up the sail look very much like an asymmetric, which is exactly what you want!
We can use these lines to move the sheet position back and forward – just like the headsail cars. In light conditions pulling tweaker on moves the sheet lead forward, and the sail gets fuller, and with less twist. In heavier conditions the tweaker is eased, the sheet lead position goes aft, the sail gets flatter, and twists the sail open.