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Upwind
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Автор: Денис   
26.11.2009 16:12
Индекс материала
Lee Bow
Push to layline
Upwind penalty
Upwind Pin
Top mark hunt
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PUSH TO LAYLINE

A common strategy for a leading boat on an upwind leg is the 'push to layline'. There are many advantageous to this strategy. When a leading boat uses its advantage to push an opponent to a layline, it is able to maintain its choice of the side of race course, keeping any tidal stream, wind strength or persistent wind shift advantage it has found. The leading team also ensures that there is little separation between itself and the opposition, reducing the chance the trailing boat will make a big gain on an unexpected wind shift.

In this example, every time Blue tacks towards the middle, or left side of the race course, Yellow tacks in a position that forces Blue to tack again, pushing the Blue boat towards the starboard tack layline. Yellow achieves this either by tacking in a 'lee bow' position, or, if the lead is larger, by tacking directly upwind of Blue, in both cases blocking or disturbing the wind that reaches the trailing boat. Blue needs to tack away immediately, often forced into a 'downspeed tack' which further extends the advantage to Yellow. The leading boat can build to full speed before tacking again.

Once at the layline, the leading boat can simply lead its opponent in to the windward mark, and will usually make another slight gain by forcing the other boat to sail in its 'bad air', or making the other boat overstand the mark, sailing a longer distance to find 'clean air'.

The trailing boat has few options in this situation. Blue can choose to initiate a tacking duel, always tacking back towards Yellow as quickly as possible. This is an aggressive option, with the intention of making a gain either by outworking the other crew, or forcing a mistake by the leading boat. It has the advantage of not allowing too much time on one tack, making it less likely the boats will reach the layline early. Of course the risk of a mistake or gear failure is increased for the trailing boat too.

Occasionally, the performance characteristics of the two boats are such that the trailing boat may simply turn through the water more quickly, allowing it to make a tiny gain with each tack. This is often enough to discourage the leading boat from continuing the push to layline.



Обновлено 26.11.2009 16:51