Sail With Air Envelope and Contour Shaping Parts

This invention relates to sails, and more particularly to the forming of an air envelope in a sail and the shaped parts for the contouring of sails.

In the building of sailboats, much effort is devoted to improving the contour of the sails and reducing the resistance or wind drag of the rigging. A well known prerequisite of sailboats is that the craft must utilize the atmospheric wind from two sides.

The use of a contour mast with a mast contour that extends sternward beyond the usual streamline form of the fixed mast is a well known approach to improving the contour of the sail and enabling the craft to utilize atmospheric wind from two sides. The contour mast generally has a rotatable arrangement and can be run with a semirigid sail or with a lath sail as described in Segler Lexikon published by Joachim Schult Verlag Klasing and Co. GmbH, Bielefeld 1978, Second Edition, page 311. In many instances the rigid sail parts have a streamlined form with concave and nonvariable arches on both sides. Rigid sails, however, have not been widely accepted because they cannot be given a slight but often critical twist which at any level above the water gives the sail the correct angle of incidence that corresponds to the wind gradient of the atmospheric wind at an increasing level of the surface of the water (cf. The Sail-Jeremy Howard-Williams, German edition published by Klasing and Co., Bielfeld and Berlin 1969).

Other known sail arrangements such as the rigging for a sail plank or surfboard with a sail as disclosed in German Pat. No. 1,914,604 and a wind propelled vehicle as disclosed in Australian Pat. No. 46552/79 relate to the attachment of the mast on a sail plank or surfboard as well as the connection between the mast and two outwardly curved main booms. The German Pat. No. 1,914,604 further teaches that the fore leech of a sail for a sail plank or surfboard can be formed as a hem into which the mast is introduced. However, it has been found that no fundamental improvement in the contour of the sail is achieved as long as the mast remains the edge of wind attack of the main sail.

It is thus desirable to provide a sail which is not dependent on the mast to form the edge of wind attack of the main sail.

Accordingly it is an object of the invention to dispose the mast and/or the stay in the sail such that the contour of the sail is not dependent upon or dictated by the curvature of the mast and/or the stay. A further object of the invention is to utilize lightweight contour forms and an inflation of a contour envelope of the sail by relative wind effects to form a contour in the sail favorable for sailing vessels.

In accordance with the present invention, the sail includes a tubular air envelope portion at a front of the sail for running on a mast and/or stay. A plurality of telescoping contour sleeves are disposed in the tubular portion to sheath the mast and/or stay when the tubular portion is run on the mast and/or stay. Each of the contour sleeves have a perforated baseplate, and a flexible tension member such as a cord is passed through one of the perforations in each of the baseplates. Knots provided in the cord above the below the baseplates hold the contour sleeves in a predetermined telescopically extended position when the sail is run on the mast or the stay. A sail mouth opening in the tubular portion receives air to inflate the tubular portion thus forming the air envelope of the sail.

Certain portions of the rigging can also be sheathed by the contour sleeves to reduce the wind resistance of the rigging. As the contour sleeves are lightweight, mobile and streamlined contour parts, the wind resistance can be reduced substantially. Thus a greater increase of speed can be obtained without the need for greater inclinations of the sailing vessel. Consequently there is optimum wind utilization of the sails. Other features and advantages of the invention will be apparent from the following description.

A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily understood by reference to the following detailed description when considered in connection with the accompanying drawings in which:

FIG. 1 shows a rigging with contour sails for mast conduction, incorporating one embodiment of the present invention;

FIG. 2 is a section taken on the line 2--2 of FIG. 1;

FIG. 3 is a fragmentary view of the contour sleeves thereof in telescopically extended position;

FIG. 4 is a perspective view of a contour sleeve thereof with a baseplate;

FIG. 5 is a fragmentary view of the contour sleeves telescopically extended for stay conduction in accordance with another embodiment of the invention;

FIG. 6 is a perspective view of a contour sleeve thereof with an oval baseplate for stay conduction;

FIG. 7 is a section taken on the line 7--7 of FIG. 6;

FIG. 8 is a fragmentary side view of a sail cap;

FIG. 9 is a plan view of the sail cap;

FIG. 10 is an enlarged fragmentary section through a mast double boom connection taken on the line 10--10 of FIG. 1;

FIG. 11 is a section taken on the line 11--11 of FIG. 10;

FIG. 12 is an enlarged fragmentary section through a stay double boom connection taken on the line 12--12 of FIG. 5;

FIG. 13 shows two sails set on the stay and support mast on a relatively large boat with a splay mast incorporating a further embodiment of the invention;

FIG. 14 schematically shows a rigging for contour sail conduction of a yacht according to FIG. 13;

FIG. 15 is a section through a mast with streamlined rotatable jacketing taken on the line 15--15 of FIG. 14; and,

FIG. 16 is a section through a double boom with sail taken on the line 16--16 of FIG. 1.

Referring now to the drawings, wherein like reference characters depict identical or corresponding parts throughout the several views, the rigging for a sail 1 is shown in FIG. 1. The rigging includes a mast 2 sheathed by contour sleeves 4 with baseplates 5 that are bonded to the contour sleeves 4. The contour sleeves 4, as shown in FIGS. 3 and 4, are connected together in telescope fashion and are formed of any suitable lightweight elastic foam material that will float easily.

The sail 1 is hoisted on the mast 2 between a double boom 8 that surrounds the sail as most clearly shown in FIG. 16. The tubular portion of the sail 1 is thus pulled over the mast 2 and the contour sleeves 4. Such pulling is facilitated by opening a pair of zippers 18, 19 provided at opposite sides of a bottom portion of the tubular part of the sail 1. The zippers 18 and 19 open from the bottom up.

Battens or sail edges 29 are provided in lath pockets 30 that extend through the tubular part of the sail to extensions 28 of the baseplates 5. The sail edges 29 are pivotally secured to the extensions 28 by means of bolts, as seen in FIG. 2, for pivotable upward and downward movement with respect to the baseplates 5.

FIG. 10 shows the connection between the mast 2 and the double boom 8 by means of a strut 10 and a clamp 9 such as sold in Germany under the trademark NIROSTA. The clamp 9 is preferably made of a rust-proof and acid-proof steel alloy and extends through one of several openings in the sail 1, such as the sail mouth 35, and embraces the mast 2. The clamp 9 has opposite extending legs fastened at both ends to the double boom 8 and a screwable bolt as shown in FIG. 11. A sliding ring 12 with a bore 13 serves to guide a turbulence cord 14 (FIG. 1).

While FIGS. 1-4 show a novel rigging for mast conduction, FIGS. 5-7 show corresponding parts for stay conduction. Contour sleeves 21, as utilized for stay conduction, are shown round, although their baseplates 22 may be oval according to FIG. 6 or round as in FIG. 7. The baseplates 22 have respective bores for the conduction of the stay 3, as well as a telescope cord 6 and a downhaul 7. As shown in FIG. 5, the contour sleeves 21 have their greatest diameter at the level of the double boom 8. The baseplates 22 are bonded to the sleeves 21, which are also preferably made of foam material.

The telescoping of the contour sleeves 4 and 21 is accomplished by means of the telescoping cord 6, a flexible tension member, which has knots above and below each of the baseplates 5 and 22 to form a connection with said baseplates and thereby hold the sleeves in a predetermined telescopically extended position. The contour sleeves 4 and 21 as shown in FIGS. 4 and 6 include cutouts 31 in the aft-leech direction which guide the lath retention extensions 28 of the next baseplates 5, 22 when the contour sleeves 4, 21 are collapsed.

Referring to FIGS. 5 and 12, the double boom 8 is connected with the stay 3, which is shackled in on the underside of a plate 11 such as sold in Germany under the trademark NIROSTA. The plate 11, which is preferably of a material similar to that of the clamp 9 protrudes through the sail mouth opening 35 of the sail 1 and has bores for guiding the stay 3, the telescoping cord 6 as well as the up and down hauls.

The sail shown in FIG. 13 is hoisted with stay conduction between a sail shoe 24 and a sail cap 25. The sail cap 25 as shown in said view in FIG. 8 and in plan view in FIG. 9 has a hole 26 at its center to receive a swivel 27 which receives the halyard. The telescoping cord 6 and a downhaul 7 are disposed at an inward prolongation of the swivel 27 in the sail cap 25. Zippers such as 18 and 19 of FIG. 1 may also be provided at the sail shoe 24.

FIG. 14 shows in schematic fashion a rigging for contour sail conduction of a yacht, with the known mast stiffenings being dispensed with for ease of description. The main sail is run, as in FIG. 13, by means of a wire stay 3, the foresail on a mast support 32. If on relatively large boats the rigging is changed by displacing the mast from midships sideways as a splay mast against the board walls, by omission of any mast struts, the best propulsion values are achieved especially on rough sailing courses.

FIG. 15 is a section through a round mast 33 from the head to the lateral board walls. In FIG. 15 the mast 33 has a streamlined rotatable sheath 34.

Some advantages of the invention evident from the foregoing description include an air envelope and shaped parts for the contouring of a sail so as to decrease the wind resistance and correspondingly lead to an increase in speed without the need for greater inclinations of the vessel. Thus the sail as disclosed herein provides for optimum wind utilization, and the contour of the sail is not dependent upon the contour of the mast or limited by its support on a stay. Thus, in accordance with the invention the wind resistance can be reduced to one seventh.