Adjustment of the aerofoil

On a Voilier the adjustment of the aerofoil consists in modifying the orientation and the form of the veil S according to the force and of the direction of the wind as well as state of the sea. The objective is that the sailing ship can advance as soon as possible:

while having a maximum driving power, or
while having the best compromise driving power/side force making gîter (to lean) the sailing ship.

Adjustment of the veils

The objective of this adjustment is to obtain a flow attached (not taken off) of the wind on the whole of the veil (to the paces of the meadows and through the wind) or only on the level of the leading edge of the veil (with the bearing paces). The adjustment of a sail consists:

to direct it compared to the direction of the wind (total Chock of the profiles of the veil). One acts as block on the whole of the veil or one modifies this orientation according to the height: it is the twist (variable chock of the profiles, generally decreasing in height: the sail is more " opened in top). This adjustment is most important.
to adapt the hollow (the camber of the profiles) at the request of driving power.

The adjustment of the veil compared to the wind depends on two factors:

of the chock of the profiles compared to the boat, it is the adjustment itself,
of the orientation of the boat compared to the wind (of which the direction fluctuates), it is the role of the cox.

A finer adjustment consisting in adapting the hollow and the twist and, in the case of the spinnaker, regulating its positioning in height, makes it possible to obtain a profit speed which can be assembled to 10-20% the speed obtained thanks to the first adjustment.

The adjustment of the veils must be re-examined in the event of change of management of the sailing ship, if the direction or the force of the wind changes, when the state of the sea evolves/moves (vague stronger, or hollower, change of orientation of the waves). The modification of the wind can be caused by the configuration of the coast or, in regatta, by the presence of close sailing ships.

Control chock, twist and hollow

For making well, these three adjustments should be separate.

It is almost the case for a grand' veil whose hoist of listening is assembled on a transverse rail (bars of listening): the position of the carriage of the hoist controls the chock of the whole of the veil, the tension of listening controls the twist of the veil. One can also act in a separate way on the hollows of the profiles, bellow on the level of the bôme and higher by modifying the curve of the chechmate (the bending of the chechmate flattens the sail).
For a sail of before not held on a bôme (gênois, jib), the adjustment is much more difficult, because three controls are not separate. A modification of the tension of listening modifies at the same time the total chock of the veil, the hollow of the bottom of the veil and its twist… the adjustment of a jib, especially if it is high and narrow (strong influence of the tension of listening on the twist), is particularly " pointu" and a good comprehension supposes what does without.

The orientation of the veil compared to the direction of the wind is carried out using the listening S: listen to jib for the veils of before and listens to mainsail for the sail éponyme. The adjustment is carried out in bordering or shocking listening. When the sail is shocked too much (or that the cox modifies too his road while lofant), it fasseye. The orientation of the pennons allows some paces to locate a flow not attached on the under-surface or the suction face of the veil. The log is also a good indicator, the increase in speed to course and constant wind indicating a priori a better adjustment.

The orientation of the Spinnaker requires the use of a great number of Bout S because of presence of a point of tack " mobile" (the end of the boom). One will be brought to modify the adjustment of the listening of the arm (with the wind), of listening, of hauls-low and the Balancine of Tangon.

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Adjustment of the hollow and the twist

The adjustment of the hollow and the twist is intended to adapt the shape of the aerofoil to the pace as for the first adjustment but also to the force of the wind and the state of the sea.

This adjustment is obtained while acting on:

points of car of listenings which are regulated for the mainsail as for the sail of before by the carriage of listening
the ropes of mainsail and of veil of before
the preventer shroud which acts on the curve of the stay and the mast and thus in by-effect on the tension of guindant sail of before and of the mainsail
the nerve of falls which act on the fall

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