Ships – Watercraft with means used in providing sailpower – Having specifically defined hull shape
Patent
1986-06-20
1988-09-27
Basinger, Sherman D.
Ships
Watercraft with means used in providing sailpower
Having specifically defined hull shape
114 90, 114 97, 114109, 254375, B63H 910
Patent
active
047733454
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The development within the windsurfing area is towards higher and more narrow sails, especially for funboards, which require higher masts, usually with an extension of the mast from previously 4.50 m to about 4.90 m, which can be achieved with a mast extender arranged at the lower end of the mast. Furthermore, new stiffer materials are used for the sails, such as "Kevlar" and "Mylar". Such new sails are less extensible and require the use of larger forces for stretching the sail along the mast and along the boom (fore or mast leech and boom leech).
SUMMARY OF THE INVENTION
According to this invention these problems are solved by arranging in or at the lower end of the mast or a mast extender intended to be arranged at the lower end of the mast a force amplifying device for stretching and locking the fore end of the sail, i.e. the fore leech. With said force amplifier a fairly small force applied by hand can be amplified, for example with at least 50%, preferably at least 200% and especially at least 300% or 500%.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial cross section through a mast extender according to a first embodiment of the invention;
FIG. 2 is a partial cross section view of a preferred embodiment of the invention arranged in a mast device;
FIG. 3 is a side view of the embodiment according to FIG. 2;
FIG. 4 is a view in the axial direction of the mast of the embodiment according to FIG. 2;
FIG. 5 is a partial cross section view of a further preferred embodiment of the invention;
FIG. 6 is a side view of the device according to FIG. 5 viewed in a direction perpendicular thereto;
FIG. 7 is a view in a direction perpendicular to the view directions of FIGS. 5 and 6 of the device according to FIG. 5;
FIG. 8 is a side view of the device according to FIG. 5 arranged on a sail-boom;
FIG. 9 is a side view of the device according to FIG. 5 arranged on a sail-boom; and
FIG. 10 is a side view of the device according to FIG. 2 arranged for tensioning a sail.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferably the force amplifier is arranged within the lower part of the mast or the mast extender. One such device is shown on FIG. 1 which is partly a section through a part 1 of a mast or mast extender and comprises a two-fold purchase with a fixed block 2 with 4 wheels 3 arranged in parallel on the same axis 4 which extends through holes in the mast (or extender) 1 and cooperates with a similar second block 5 with 4 wheels 6 arranged on the same axis 7 which extends through two longitudinal openings 8 in the mast. The two blocks 2 and 5 are connected with a rope 9 in the usual way for such a per se known device, and one end 10 of said rope extends through an opening 11 in the mast at which there is arranged a pulley wheel or a similar device which permits passing the rope out from the inside of the mast with a low friction. The movable block 5 is provided with a fastening means 13 for one end of a second rope 14, the other end 15 of which extends through an opening in the mast, preferably via a first pulley wheel 16 and a second pulley wheel 17 arranged at an opening 18 in the mast. The outer end 15 of the ropes 17 is secured to the tack 19 of a sail as is shown sketchily on the figures. A force applied in the direction of arrow 20 will thus cause an amplified force acting in the direction of the arrow 21 on the sail.
FIGS. 2-4 show a preferred embodiment of the invention according to which a mast extender 1 or a mast end is provided with a rope drum 2 with a cylindrical part 4 on which a rope 5 which is secured to the drum can be winded up by turning the rope drum 2. The rope drum may be provided with end flanges 3, 3' but these are not absolutely necessary and the drum may consist of a straight, preferably cylindrical shaft. The rope drum can be turned with the aid of a crank 6 or a fulcrum which is arranged on the outside of the mast extender or mast and is connected to the rope drum. According to the figure this connection is provided by a shaft 7 on w
REFERENCES:
patent: 2561253 (1951-07-01), Wells-Coates
patent: 2919108 (1959-12-01), Buechting
patent: 3228372 (1966-01-01), Ridder et al.
patent: 3452700 (1969-01-01), Horgan, Jr.
patent: 3867896 (1975-02-01), Merry
patent: 4469040 (1984-09-01), Gougeon et al.
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