Les livres (et les experts) disent que le bateau est/devient ardent lorsque le "centre de poussée vélique" est un peu trop en arrière du "centre de dérive"
En pratique le bateau gite, lofe et bien souvent, à part de l'inconfort on ne gagne rien. Le bateau est en général aussi rapide et plus confortable si on réduit la gite et qu'on limite la tendance à lofer.
Lofer en anglais se traduit par 'weather helm' et il y a là dessus un très bon fil de discussion sur le Cruiser Forum sous le titre "Weather Helm". En voici une extrait en anglais, accessible en cliquant sur le lien précédent: j'ai la flegme de traduire ...
Poor balance (Weather Helm) increases as the “Centre of Effort” moves aft of the “Centre of Lateral Resistance”, and can also be caused by warped rudders, skegs, and keels/centerboards, or even by baggy sails.
Sail trim to move the C of E forward, and reduce weather helm:
Remove mast rake (or even rake slightly forward).
Reduce wind pressure on the main, or increase the pressure on the head sail. This can be done by shaping (trimming) the sails, and dropping the main to leeward. As the wind increases, shape/position become more critical (should be flatter). If you can, tighten the backstay. This helps to pull the fullness out of the main and will flatten the head sail. The idea is to flatten the sails and keep the draft forward.
Tighten the outhaul to flatten the bottom part of the main. At the same time tighten the Main and Genoa halyard to keep the draft(s) forward. Bottom batten should line up with boom, top batten with masthead. Twist at the top of the mainsail will allow wind to spill.
Move the Genoa lead aft to flatten the lower section and twist off the leech.
Dropping the boom to leeward after shaping will reduce weather helm.
Add a boom vang (helps maintain shape when easing out).
More weight aft and windward, less weight in the bow (move anchor, empty the water tank in bow)
Reef (the main more than the jib).
Il faut aussi lire la suite de la discussion car elle est pleine de bonnes informations ... pour moi au moins.
En pratique le bateau gite, lofe et bien souvent, à part de l'inconfort on ne gagne rien. Le bateau est en général aussi rapide et plus confortable si on réduit la gite et qu'on limite la tendance à lofer.
Lofer en anglais se traduit par 'weather helm' et il y a là dessus un très bon fil de discussion sur le Cruiser Forum sous le titre "Weather Helm". En voici une extrait en anglais, accessible en cliquant sur le lien précédent: j'ai la flegme de traduire ...
Poor balance (Weather Helm) increases as the “Centre of Effort” moves aft of the “Centre of Lateral Resistance”, and can also be caused by warped rudders, skegs, and keels/centerboards, or even by baggy sails.
Sail trim to move the C of E forward, and reduce weather helm:
Remove mast rake (or even rake slightly forward).
Reduce wind pressure on the main, or increase the pressure on the head sail. This can be done by shaping (trimming) the sails, and dropping the main to leeward. As the wind increases, shape/position become more critical (should be flatter). If you can, tighten the backstay. This helps to pull the fullness out of the main and will flatten the head sail. The idea is to flatten the sails and keep the draft forward.
Tighten the outhaul to flatten the bottom part of the main. At the same time tighten the Main and Genoa halyard to keep the draft(s) forward. Bottom batten should line up with boom, top batten with masthead. Twist at the top of the mainsail will allow wind to spill.
Move the Genoa lead aft to flatten the lower section and twist off the leech.
Dropping the boom to leeward after shaping will reduce weather helm.
Add a boom vang (helps maintain shape when easing out).
More weight aft and windward, less weight in the bow (move anchor, empty the water tank in bow)
Reef (the main more than the jib).
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