Keel wooden boats is a long beam constitutes an important element of the structure. But because of its low height compared to Overall, the keel is not an anti-drift sufficient (except rear). Indeed, a bate in with the wind on his front undergoes a side effect, the de bank, he thwart his ut pa r surf aces vertical submerged. On older boats, the hull is mainly used to plan anti-drift. Its effectiveness depends on its form.
This photo of Grand Léjon and Pauline the stranding shows available to their bowling: single beam on the front half, much deeper at the rear. The draft, the more strong in the back than the front, lets go upwind satisfactorily. If the plan-drift is not sufficient, especially on flat-bottomed boats can be added, on small boats, a lift to drift pui ts in the axis of the boat: Small vessels without ballast, called dinghies, have a retractable vertically (dagger), they may only sail near the coast and in sheltered waters. Others drift which pivots in the longitudinal direction. This solution is adopted for dinghies, but also weighted dinghies, which are seaworthy boats. The ballast keel is some shallow, which axis is pierced with a permeable slit thin drift (plate or metal plate). This soution ery was spread on the plywood sailboats of the 1960s, such as those designed by JJ Herbulot (Capri, etc.) or by Philippe Harle (Muscadet, Cabernet ...). Others, called dinghies full have a ballast built into the bottom of the vessel and forming a sole grounding, drift, adjustable in the longitudinal direction, is thicker than in the previous case and shaped. This solution is adopted for many cruising sailboats or small ways.
This image shows two dinghies failed. The small, a Blue Djinn is polyester, has funds rather flat, a shallow draft and a lifting rudder. The largest, a UFO , aluminum, has a deeper keel and funds V. Notice the chine above the waterline. 
Tara is one of the largest dinghy : We see above how easy this boat, designed to navigate through the ice and "ask" on the ice, may fail flat. Another solution, adopted by the English for the Thames barges and especially by the Dutch, is that of lateral drifts : it lowers drift to leeward when sailing upwind .
This photo of Dutch barge (tjalk) shows the lateral port in the raised position. The direction of this drift, often gave a near vertical position at the cottage as is the case for the small Dutch cutter below, which we can see the 2 drift noted.
Finally, many modern boats, keelboats called, have a deep keel, independent of the structure of the boat and bolted ed through the bottom of it. The keel may be terminated by a bulb, whose weight has a neck ple recall that limits the cottage.
There are boats BIQUILLES (a keel on each side ).
Surprise This is a modern biquille; its 2 pins are at their end, bulbs used as ballast. A grounding, the boat rests on his bowling and his saffron. The racing yachts have a most modern steerable keel from side to side , system that was difficult to make reliable, but limits the cottage and provides better performance closely.
Above we see BritAir , the 60 feet of Armel Le Cleac'h, rising to nearly starboard tack (that is to say that the wind comes from the right). The keel is clearly visible thanks to its red color, is directed to starboard. Note also that the rudder is inclined and out of the water, the port rudder, completely submerged, is vertical and thus has a more effective performance management. 
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