2006

Invented in Nantes by naval architect French Fran1cois LUCAS, the principle of the keel 3D is simple and consists of equipping to all the joint keel-bulb 3 degrees of freedom. This allows besides the tilted lateral motion since they make for example the VOR70, a longitudinal adjustment forwards or backwards, as well as an adjustment according to the vertical axis allowing the change of incidence of the keel on the direction of advance of the boat.

For it the keel rests on a joint with sphere form that acts like a pivot and on which can be oriented the joint keel-bulb with 30º of angle to each lateral side and with 15º in the longitudinal axis. Around 1 meter of displacement of stern prow!

The possibility of fitting the keel forwards or backwards is realized by means of a hydraulic piston and their changes of support allow to change the longitudinal seat of the boat. With loose winds he is very advantageous to advance the keel to take off the stern of the water and to limit the resistance and the drag by wet surfaces being advanced the center of drift of the boat. When little wind also blows is placed the keel to leeward to force lists a little it of the boat and therefore to reduce the wet surface of the careening.

With lifting winds and of the traverse, the keel positions everything to stern to seat the boat, to avoid the nailed ones of prow in the waves and to delay the drift center. Obvious one moves laterally to leeward to increase the adrizamiento and to maintain the flattest boat and with more power in the candles. If it refreshes the time, acting on the hydraulic piston during about 20 seconds, we will be able to delay to the bulb of 300 kilos towards the stern, increasing the course stability. Whatever longitudinal direction, the bulb always is parallel to the waterline by means of an ingenious system based on articulated axes.

The adjustment of the incidence is very useful during the fitted ones since the positive incidence that can be given the keel causes that this acts as an airplane wing and increases to the sustenation of the aileron reducing the drag. The result is that the discouragement of remarkable form falls. On the contrary, with lifting winds a negative incidence occurs to the keel forcing to the sailboat to a a little lateral movement (like the crabs) which allows to luff a little more and therefore to favor the laminar flow of the wind on the candles, and therefore to increase the speed, with truly impressive results.

Each of these three adjustments (pendular, longitudinal and angle of incidence) are independent of the other, and the modification of one of them does not imply the misalignment of the other two, facilitating the global adjustment. During the past edition of Transat 6.50, this new advance in naval technology was proven on the prototype nº 231 patroneado by Nicholas Bunoust.