86 COACHING FUNDAMENTALS
CE AND CLR
In order to change direction we lean the rig back to steer upwind and forwards to steer downwind. The
lift created by the flow of air over the sail is best represented by a point in the middle of the sail above
the boom and is called the centre of effort (CE).
With some of the lift from the sail pushing the board sideways the board opposes this sideways force along its
length. This unwillingness of the board to slide laterally is known as its lateral resistance and the mid point of this is
essentially in the middle of the board or on the daggerboard and is known as the centre of lateral resistance (CLR).
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When the CE is directly above the CLR then the board will travel forwards in a straight line as the equipment is
in balance
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Leaning the rig backwards puts the CE behind the CLR and the board will turn upwind (heading up). The back of
the board is pushed downwind as the board pivots in the middle
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Leaning the rig forwards puts the CE forwards of the CLR and the board turns downwind (bearing away). The front
of the board is pushed downwind as the board pivots in the middle.
Further, in order to steer downwind effectively, we must lean the rig towards the wind as well as forwards. When I am
running the early phases of instructor training I always ask the candidates why they think the rig needs to be leaned
towards the wind as well as forwards yet I seldom procure the correct answer. So lets look more closely at this.
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WIND
SURFING