Ships – Keels – Vertical adjustment
Patent
1985-12-30
1987-11-03
Peters, Jr., Joseph F.
Ships
Keels
Vertical adjustment
114138, B63B 4100
Patent
active
047037083
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention pertains to the general field of sailing boat keels and more particularly to a keel having a stationary keel section and one or two rotatable sections that are independently controlled from the boat deck.
BACKGROUND ART
The art of designing keels for sailing boats has progressed from weighted bulky structures as used on ancient reed boats and Columbian era boats to todays keel designs that employ aerodynamic fins.
Current fin keels are basically designed to achieve optimum laterial resistance with minimum drag and to optimize the aspect ratio of the keel so that the heeling forces are minimized. The resulting drag curve for these current designs is very steep at speeds between 5 to 8 knots. Therefore, the upwind speed is severly limited. In general, it can be said that prior art keels are designed primarily for boat stability rather than to achieve an increase in speed.
A search of the prior art did not disclose any patents that read directly on the invention. However, the following U.S. patents are considered related and indicative of the prior art:
______________________________________ PATENT NUMBER INVENTOR ISSUED
______________________________________
768,085 Stromborg 23 August 1904
398,900 Martin 5 March 1889
367,771 Witmer 2 August 1887
______________________________________
The Stromborg patent discloses a double-balancing safety-keel apparatus for use on sailing vessels. The apparatus is comprised of two vertically stacked fins or blades that pivot about a vertical axis located at the longitudinal center of the vessel. Each blade may be horizontally rotated on its axis independently of the other or both may be rotated or tuned simultaneously.
The Martin patent develops a steering gear apparatus for use on small sailing vessels. The apparatus is comprised of two in-line blades that are designed to be used both as rudders and centerboards. One blade is located at the aft end and the other at the forward end. Each blade may be extended or retracted independently of the other and the blades may be operated together or singularly. When the vessel is running before the wind, the forward blade would be retracted out-of-use leaving the aft blade to serve as the sole rudder.
The Witmer patent discloses a combined double-action steering and braking apparatus for use on sailing vessels. The apparatus is comprised of two retractable rudders, one located near the forward end and the other near the stem of the vessel. The posts of the rudders are connected by cross-cables so that both rudders may be operated simultaneously. When the rudders are turned, with respect to the centerline of the keel, they function as conventional steering rudders. However, when they are positioned normal to the keel a breaking action is produced.
DISCLOSURE OF THE INVENTION
The steerable keel is presented in two embodiments, the first is a keel design employing an upper stationary section and one rotatable section while the second embodiment has an upper stationary section and two rotatable sections. In either design the amount of rotation desired is independently controlled by a tiller or set of tillers depending on the embodiment. The keels in either case have an aerodynamic foil cross-section and extend below the boat hull for a total of 12 feet (3.66 meters). Because of this length a means is provided that allows the steerable keel to be retracted to allow the boat to dock and navigate is shallow waters.
The steerable keel is designed to be used with sailing boats and in particular high-speed sailing boats. The purpose of the keel and its primary object is to maintain lateral stability and thus gain an increase in speed. Lateral stability is achieved when the keel produces a below water lifting force that tends to equalize the wind force and the reacting below water counterforce on the keel. The amount of equalizing force applied is dependent on the amount of boat heel, the wind force and the sail conditions. Whatever the level of the applied force, it is controlled by se
REFERENCES:
patent: 433955 (1890-08-01), McPartland
patent: 768085 (1904-08-01), Stromberg
patent: 3946693 (1976-03-01), Brown
patent: 3990384 (1976-11-01), Reynolds
patent: 4000933 (1977-01-01), Derman
patent: 4067280 (1978-01-01), Serfess
patent: 4226206 (1980-10-01), Wilson
patent: 4316425 (1982-02-01), Guido
patent: 4376416 (1983-03-01), Carver
patent: 4543069 (1985-09-01), Koayashi
patent: 4563971 (1986-01-01), Carver
Bartz Clifford T.
Cota Albert O.
Peters Jr. Joseph F.
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