The magic keel

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In the last twenty-five years, architects and boatyards have increased the volume and the comforts of cruising sailing yachts, which became vaster, better equipped, but also heavier than their forebears, without losing performance (except to windward). To improve speed, cruising sailboats would have to receive the same injection of power as racing ones, but without such costly construction and devices (as multiple hulls or pivoting keels). This is precisely what the Magic Keel promises - with, on top of it, a minimized draft in harbour.

Imagine a cruising yacht - actually, she can be one of an existing class, since the Magic Keel can be installed without hull modifications. In harbour two details distinguish such a Magic Keel-equipped yacht from her sister-ships with a normal keel. First, her rig is much bigger, with some 35 to 50 % more sail area. Second, she can drop her anchor in much less water because her draft is reduced by 40 to 50 %. Out of the water, this sailboat doesn't need a cradle, since the Magic Keel then acts as a twin-keel. When sailing, the crew may chose between comfort and performance. In the first case, they'll reduce the sail early and go at the same speed as the others with half the heel - the pleasure of a monohull with the comfort of a catamaran ! In the second case, they'll benefit, for the same heeling angle, from 35 to 50 % more propulsive power, and hence a vastly increased speed.

The Magic Keel is a moving keel shaped like a bow. At the moorings, the bow is centred under the hull, earch portion protruding equally, like a twin-keel. When sailing, this bow-keel slides on rollers to move to the upwind side of the hull. Not only is the weight of the keel then in a favourable position to increase stability, but also the whole surface of the bow-keel acts as a centreboard, with a 30 % increased draft compared to a usual keel. When tacking, an electric motor powers the Magic Keel from one side to the other in some ten seconds. At his speed, electric consumption remains amazingly low : between 0.2 and 0.3 amps per tack for a 1-Ton Magic Keel. A 12v/200 amps battery will be enough to tot up 400 or 500 tacks before becoming discharged.

The Magic-Keel is the end-result of a long research. At the start, there is the invention of a technician in love with sailboats, Daniel FIDELLE, who dreams of a monohull less heel-prone than the others, and invents a system of sideways moving ballast under the hull. This invention wins a national competition organised by Oséo-Anvar, a delegation from the French Ministry of Research and Technology. She receives the help from an office of the Nord-Pas de Calais region, the MITI, and from the hydrodynamicists of the French Direction Générale de l'Armement (DGA). All this allows her to finance in-depth technical researches.

Other than the Magic Keel, four other types of keels allow for a draft reduction while increasing stability on sailboats from 5 to 40 meters.

The French research centre for mechanisms, CETIM, computes and optimizes the Magic Keel drive system.

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