We designed swing keel systems for yachts of different sizes. Among those was a 68 ft yacht from GRP (composite construction) with a 14 t heavy keel foil. The draft of this keel is 3,85 m if the foil is extended. If the foil is up, the draft is reduced to 1,55 m. These are remarkable values, which allow this yacht to sail almost in every marina or waters.
Swing keels are good choice with deck house yachts, that have a raised seating arrangement, since the keel system can be placed usually not visible under these arrangements. The hydraulic system though has to provide a little more power, since the keel foils are moved around big bearings and a geometric solution is required.
Additionally an opening behind the foil if in sailing position results when the keel is down. It requires to be closed, since the dynamic of the seawater can result in noise and resistance when expanding in this opening. We therefore designed a clothing mechanism that automatically closes this opening when the keel is lowered and it opens again fully automatically if the keel is raised.
All our keel systems work without any problems for years now.
We designed lifting keels for different size yachts. One advantage of a lifting keel is that the hydraulic system has to overcome only the weight of the system, the weight of the bulb and some friction.
The major difference in lifting keel systems is the length of the keel box, which can reach from hull bottom to the deck, providing the maximum lift possible. We designed other systems that disappear in the galley area in a counter and do not disturb the open layout of the interior arrangement. The lift – depending of the size of the yacht – is about 70 cm. Our keel systems are calculated with sufficient reserve in strength and have safety device, that make a loss duringn normal use – so to say – impossible.
All our keel systems work for many years without any problems.
The need and the demand has always be present, but has been increasing, because climate changes show influence even in the use in sailing and in storing yachts.
Therefor it is not anymore only the need to sail in shallow bays and marinas. It is even more important to be able to leave the yachts berth and return to it at all under the given conditions.
The telescopic keel system is especially useful for new existing designs, since the interior arrangement needs not to be changed. The existing interior structure can remain, since moments and keel weights and loads can be matched to the existing fixed keel design. An overload of the interior structure can be avoided. Also, aim is, to maintain size and position of the keel bolts.
The concept is a telescopic keel system, that can be fitted to many existing designs. This means that yachts of about 40 to 60 ft length can reduce the draft by about 70 cm. Meaning, that yachts with a total draft of about 2.50 m can reduce the draft to about 1.80 m.
We calculate the amount of draft reduction and keel design for every yacht individually.
Every keel system contains safety devices, that a loss of the keel under normal operation conditions is not possible.
Also the system contains reasonable safety factors.