Ships – Apparatus held by or attached to rider to control sailboard... – Foot strap means
Patent
1991-07-05
1993-12-21
Basinger, Sherman
Ships
Apparatus held by or attached to rider to control sailboard...
Foot strap means
114 91, 114103, 114105, B63H 906
Patent
active
052713490
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a wing sail structure of a type which comprises a mast, or supporting spar, mounted rotatably on a boat, and a sail which can be lowered.
More particularly, but not exclusively, the invention relates to a wing sail for boats, and throughout this specification reference will be made to such field of application for simplicity of illustration.
2. Background Art
Some special boats usually intended for racing events have been recently rigged, as is known, with rigid sails commonly called wing sails on account of their sectional profile duplicating basically that of an airplane wing.
It has been observed that this type of sail can improve the aerodynamic qualities of a sailboat and afford higher cruising speeds to be attained and maintained. It has, however, a fault in that it is difficult to handle and troublesome to lower.
To overcome this drawback, the prior art has proposed a solution described, for example, in USSR Patent No. 1034945.
That document discloses a wing sail of the rigid type comprising a plurality of segments with essentially airfoil sectional shape which are arranged on top of one another, on opposed sides with respect to a mast extending vertically upwards.
The segments are interconnected in pairs, on either sides of the mast. The adjacent sides of each segment pair are hinged together, whilst their end sides are guided slidably along the mast such that the sail structure can be folded down into two separate packs at the mast base.
The sail working arrangement consists of ropes or "lines" connected to the end segment, and sail area is reduced by decreasing the number of the segments hoisted.
This prior approach, while substantially achieving its objective, still has some shortcomings as pointed out herein below.
In the first place, sail area cannot be reduced, or the sail be reefed down, in a continuous fashion. Further, the airfoil shape of the sail can only be achieved effectively with the various segments fully extended vertically.
Further shortcomings originate from the excessively complicated construction of the sail, which is also the cause for high cost and low reliability.
A second prior technical solution is known from another USSR patent, No. 1159829, relating to a biplane wing sail made up of two parallel portions, symmetrical about the mast and each comprising like rigid airfoil segments which are structurally independent and aligned vertically above one another.
Each of said segments is hinged centrally to the free end of an arm which cantilevers perpendicularly out from said mast. Corresponding parallel segments are hinged to respective, opposed arms jutting out from a slide guided for sliding movement along the mast and whereto they are connected rotatably.
By first rotating the airfoil segments through 90.degree. and then their supporting arms on each slide, such wingsail segments can be disposed with their axis parallel to the boat's deck, and each pair can be lowered by hauling down its corresponding slide.
This approach is also complicated and expensive to implement. In addition, the sail in the lowered condition is quite bulky and interferes with the normal handling of the boat.
The technical problem that underlies this invention is to provide a wing sail structure having a uniquely simple and functional construction whereby it can be reefed down or lowered altogether, according to necessity, with few operations, and at the same time obviate the shortcomings mentioned above in connection with the prior art.
DISCLOSURE OF INVENTION
This problem is solved by a wingsail structure as indicated being characterized in that said sail comprises a plurality of ribs encircling the mast and being guided slidably along said mast, and a fabric skin wrapped around said ribs.
In a preferred embodiment, said mast is provided with at least two opposed, parallel longitudinal grooves forming respective guides for running carts attached to the ribs.
The features and advantages of the wing sail structure according to the invention w
REFERENCES:
patent: 3381647 (1968-05-01), Keeler
patent: 3580203 (1971-05-01), Martin
patent: 3724412 (1973-04-01), Blecker
patent: 4341176 (1982-07-01), Orrison
patent: 4386574 (1983-06-01), Riolland
patent: 4624203 (1986-11-01), Ferguson
patent: 4685410 (1987-08-01), Fuller
patent: 4909170 (1990-03-01), Smart
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