US3820493A - Sailboat improvements - Google Patents

Abstract

A fore-and-aft rigged sailboat that has a sail made of flexible material, and includes a flap portion that is adapted to lie on the deck when the sail is in the close-hauled position so as to prevent any substantial flow of air laterally under the sail from the windward to the leeward side thereof. The sail may be either a jib or a mainsail and some embodiments have a transparent panel to provide visibility.

Description

United States Patent 1191 f 1111 3,820,493 Amick June 28, 1974 SAILBOAT IMPROVEMENTS 103.

[76] Inventor: James L. Amick, 1464 Cedar Bend Ann Mlgll" 58105" Primary Examiner-Trygve M. Blix [22] Filed: Oct. 26, 1972 Assistant Examiner-Stuart M. Goldstein [21] AppL No: 301,231 Attorney, Agent, or FirmOlsen and Stephenson [52] U.S. Cl 114/102, 114/39, 114/103 [51] Int. Cl B63h 9/04 [57] ABSTRACT [58] Field of Search 114/39, 102, 103

A fore-and-aft rigged sailboat that has a sail made of References Cited flexible material, and includes a flap portion that is UNITED STATES PATENTS adapted to lie on the deck when the sail is in the close- 2,499,59s 3/1950 Maurer et al. 114/103 hauled Position as any Substantial flow of 3,438,349 4/l969 Curtis et al. 114/102 air laterally under the Sail from the Windward 10 the leeward side thereof. The sail may be either a jib or a FOREIGN PATENTS OR APPLICATIONS mainsail and some embodiments have a transparent 83,3l3 l/ 1963 France 114/103 panel to provide visibility OTHER PUBLICATIONS New on Water; Mar. l956; Popular Science, pg. 12 Claims, 4 Drawing Figures PATENTEDJUNZB I974 (820,493

SHEET 2 BF 3 I SAILBOAT IMPROVEMENTS BACKGROUND OF THE INVENTION The present invention relates to improvements in sails of the type used in fore-and-aft rigged sailboats.

In the use of conventional sails a gap exists between the foot of the sail, often fastened to a boom, and the hull. This gap has a detrimental effect in the sailboat performance, because it allows air to flow through it from the high pressure or windward side of the sail to the low pressure or leeward side. It is known from observations on airplane wings that such a flow at a lateral edge of a wing induces a flow in the opposite direction ahead of the wing causing the so-called induced'drag, so that in the case of a sail, the relative wind which the sail experiences comes from closer to the bow than it would if there were no gap flow. A relative wind closer to the bow produces a sail force which has a smaller forward component, and therefore, less propelling capacity.

The gap between the foot of the sail and the hull is also detrimentalfrom the standpoint of the desirability of minimizing the overturning moment produced by a given sail force.

SUMMARY OF THE- INVENTION The present invention has overcome some of the inadequacies existing in fore-and-aft rigged sailboats, and particularly in the construction of the sails of such boats.

According to one form of the present invention, a fore-and-aft sail is provided comprising a sheet of flexible material that. is secured at its upper end to the mast of the sailboat and extends downward to the deck to form an upright portion and then extends inboard or inward to form a flap portion that is adapted to lie on the deck when the-sail is in the close-hauled position so as to prevent any substantial flow of air laterally under the sail from the windward side to the leeward side thereof. The flexible material preferably includes a transparent panel located in the upright portion immediately above the flap portion to improve visibility. This construction and arrangement reduces the induced rag acting on the sail by preventing air flow from the windward side of the sail to the leeward side between the sail and the hull. It also provides an improved ratio of the sail force relative to the overturning moment by filling the usual gap at the bottom of the sail with a downward extension of the sail which develops additional sail force with comparatively little overturning moment.

Thus, it is among the objects of the present invention to provide an improved sail in which induced drag is re duced by elimination of the gap between the bottom of the sail and the hull so as to prevent air flow from the windward side of the-sail to the leeward side between the sail and the hull, the sail-hull juncture being sealed by means of a flap portion which consists of an extension of the sail, part of the flap portion lying in a generbeing had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fore-and-aft rigged sailboat which includes a mainsail embodying one form of the present invention;

' FIG. 2 is a fragmentary perspective view of a foreand-aft rigged sailboat which includes a jib embodying another form of the present invention;

FIG. 3 is a fragmentary perspective view of a modified form of the jib shown in FIG. 2; and

FIG. 4 is a fragmentary perspective view of a modified form of the mainsail shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein. is for the purpose of description and not of limitation.

Referring now to the drawings, the embodiment of the invention illustrated in FIG. 1 will be described first. The fore-and-aft rigged sailboat 10 has a deck 12, a mast 14, a swivel 16 mounted on the deck 12, and a boom 18 connected at one end to the swivel 16. The mainsail 20 is connected at its forward edge to the mast 14, and it has its clew or first attachment means 22 connected to the aft end of the boom 18. The mainsail 20 is contoured so as to have an upright portion 24 which extends from the peak 26 to approximately the level of the clew 22, and an integral flap portion 28 which extends inwardly from the upright portion 24 so that it can lie on the deck 12 to prevent substantial flow of air laterally under the mainsail 20 from the windward to the leeward side thereof when in the close-hauled position. The flap portion 28 has second attachment means 30 in the form of a sleeve extending along the after edge of the flap portion.

Securing means 32 are provided for positioning the after end of the boom 18 and the flap portion 28 in their proper locations. The securing means 32 includes the pulley 34 mounted on the end of the boom 18, and a transverse traveller 36 mounted on the hull of the sailboat 10. A line 38 is connected at one end to the traveller 36 by a clasp 40 which is adapted to slide on the traveller 36. The other end of the line 38 passes through the pulley 34 and from there through a guide tube 42 mounted on the boom 18. The line 38 then extends fromthe opposite end of the tube 42 to the pulley 44 which is also supported on the boom 18, and then extends to the jam cleat 46.

Preferably, the mainsail 24 has a window 48 of thin transparent plastic to provide increased visibility which has been reduced from the conventional sails because of the position of the flap portion 28. The flap portion 28 may be a simple extension of the upper portion of the sail 24, folded over to lie flat on the deck 12. A smoother transition between the curved main part of the sail and the flap portion can be produced by sewing tucks in the flap, as can be seen in the drawings. In addition, the flap 28 may be made of elasticized material to allow for changes in the sail curvature under varying conditions.

The sleeve 30 through which the line 38 passes is positioned so that its end nearest the boom is farther from the mast than its other end, which comprises the aft inboard corner of the flap portion. Therefore, tension on the line 38 causes the inboard corner of the flap portion to move as far inboard as possible. After this comer reaches the traveller 36, further inboard movement of the boom 18 causes the flap portion 28 to arrange itself in fore-and-aft folds.

To move the mainsail 24 from one side of the boat to the other, the line 38 is released and the boom and flap portion merely lifted overhead and placed on the other side. The flap portion 28 will remain on the starboard side of the boom 18 when the boat is on either a port or starboard tack, but in either situation the flap portion 28 will be urged by the wind against the deck 12 when in a close-hauled position such as is shown in FIG. 1. The guide tube 42 through which the line 38 moves between the two boom pulley 34 and 44 prevents the line 38 from being heldinadvertently by the hand that grasps the boom to lift it overhead.

Attention is now directed to FIG. 2 of the drawings for a more detailed description of the invention as applied to a jib. The sail or jib 50 includes an upright portion 52 in which is located a window 54 made of trans parent plastic material which provides improved visibility, and an integral flap portion 56 extending from the upright portion 52 and contoured so that it extends inwardly therefrom to lie on the deck 58 of the sailboat 60 so as to prevent substantial flow of air laterally under the sail 50 from the windward to the leeward side thereof, when in the close-hauled position.

The sailboat 60 includes the mast 62 to which the sail 50 is attached at its upper end. The sail 50 also includes the attachment means or clew 64 located at the after edge of the sail adjacent to the lower end of the upright portion 52. The flap portion 56 has an attachment means 66 at its inboard after end and a securing means 68 is provided for maintaining the flap portion in the proper position. In the illustrated form of the invention the securing means includes the cleat 70 and the auxiliary line 72. A line 74 is normally connected to the clew 64 and passes through the pulley 76 on the deck 58 to the winch 78. Similar cleat 80, pulley 81 and winch 82 are provided on the port side of the boat 60 to be used in conjunction with the sail or jib 50 when the latter is positioned on the port side of the sailboat. In the conventional manner, a tack 84 is provided for securing to the forward end or attachment means 86 of the jib or sail 50.

- When the sail 50 is close hauled, essentially all of the flap portion 56 is in contact with the deck 58. As the sail is' let out, less and less of the flap portion 56 remains on the deck. The point at which a gap begins to show between the aft part of the flap 56 and the hull of the boat 60 depends upon how wide the flap portion 56 is made.

From the foregoing descriptions of the two illustrated embodiments, it will be understood that a sail embody ing the present invention differs from the usual sails in that it extends downward to the deck, and when close hauled, contacts the deck in such a manner as to substantially prevent air flow between the sail bottom and the deck. This is accomplished by having the lower part of the sail turned inboard as a flap portion which is more or less horizontally disposed on the deck. The pressure difference between windward and leeward sides of the sail tends to seal this flap portion against the deck.

FIG. 3 shows a modified jib 88 which has an upright portion 90 and a flap portion 92, but in this form of the invention a clew 94 is the only attachment means provided at the after end of the flap portion 92. A securing means 96 comprising the line 98, pulley 100 and winch 102 is provided for securing the flap portion 92 as well as the remainder of the after end of the jib 88 in a desired location.

FIG. 4 shows a modified mainsail 104 which has an upright portion 106 and a flap portion 108, and again, this modified sail has only a clew for securing the after end of the mainsail 104 and its flap portion 108 to the boom 112.

In operation, the jib 88 and the mainsail 104 will function essentially the same as the corresponding jib 50 and mainsail 20 illustrated in FIGS. 2 and 1, respectively.

It is claimed:

1. In combination, a sailboat that has a mast and a deck, and a fore-and-aft sail comprising a sheet of flexible material that is secured at its upper end to said mast and extends downward to said deck and is contoured to form a flap portion of a sufficient dimension to lie on the deck substantially its full fore-and-aft dimension when the sail is in the close-hauled position so as to prevent any substantial flow of air laterally under said sail from the windward side to the leeward side thereof, said sail being a jib that has first attachment means at its forward lower end for fastening a tack, second attachment means at the lower after end of said upright portion for fastening a jib sheet, and a third attachment means at the inboard after end of said flap portion for fastening an auxiliary line.

2. The combination that is defined in claim 1, wherein said flexible material includes a transparent panel located in said upright portion immediately above said flap portion.

3. A fore-and-aft rigged sailboat having a deck, a mast, a swivel on said deck aft of said mast, a boom connected at one end to said swivel, a mainsail connected at its forward edge to said mast and having its clew connected to the other end of said boom, said mainsail being contoured so as to have an upright portion extending from its upper end downward approximately to the level of said clew and a contiguous flap portion extending inwardly therefrom to a position lower than said boom to lie on said deck to prevent substantial flow of air laterally under the mainsail from the windward to the leeward side thereof when in the closehauled position.

4. The fore-and-aft rigged sailboat that is defined in claim 3, wherein said flap portion has attachment means at its after end, and securing means are fastened to said attachment means for positioning said flap portion.

5. The fore-and-aft rigged sailboat that is defined in claim 3, wherein said mainsail has a transparent panel located in said upright portion.

6. A fore-and-aft rigged sailboat having a deck, a mast, a swivel on said deck aft of said mast, a boom connected at one end to said swivel, a mainsail connected at its forward edge to said mast and having its clew connected to the other end of said boom, said mainsail being contoured so as to have an upright portion extending from its upper end downward approximately to the level of said clew and a contiguous flap portion extending inwardly therefrom to lie on said deck to prevent substantial flow of air laterally under the mainsail from the windwardto the leeward side thereof when in the close-hauled position, said flap portion having attachment means at its after end, a securing means fastened to said attachment means for positioning said flap portion, said attachment means comprising a sleeve extending along the after edge of said flap portion, and said securing means including a line passing through said sleeve.

7. The fore-and-aft rigged sailboat that is defined in claim 6, wherein said securing means also includes a pulley on the end of said boom, and a transverse traveller mounted on said sailboat, said line being connected at one end to said traveller by a clasp adapted to slide on said traveller, the other end of said line passing through said pulley for controlling the position of the mainsail. 8. The fore-and-aft rigged sailboat that is defined in claim 7, wherein a second pulley is mounted on said boom forward of the first pulley, and a tube extends lengthwise of said boom, and said line extends from said first pulley through said tube and said second pulley.

9. A fore-and-aft rigged sailboat having a deck, a mast, a sail connected at its apex to said mast and having a clew, said sail being contoured so as to have an upright portion extending from its upper end downward approximately to the level of said clew and a flap portion extending inwardly therefrom to lie on said deck to prevent substantial flow of air laterally under the sail from the windward to the leeward side thereof when in the close-hauled position, first securing means connected to said clew, said flap portion having attachment means spaced from said clew at its inboard after end, and second securing means connected to said attachment means for fastening said flap portion with its inward edge on said deck.

10. The fore-and-aft rigged sailboat that is defined in claim 9, wherein said first and second securing means comprise lines releasably attached to said deck.

11. The fore-and-aft rigged sailboat that is defined in claim 9, wherein said sail has a transparent panel located in said upright portion.

12. A fore-and-aft rigged sailboat having a deck, a mast, a sail connected at its apex to said mast and having a clew, said sail being contoured so as to have an upright portion extending from its upper end downward approximately to the level of said clew and a flap portion extending inward therefrom and dimensioned to lie on said deck to prevent substantial flow of air laterally under the sail from the windward to the leeward side thereof when in the close-hauled position, said flap portion terminating at its after end at said clew, and securing means connected to said clew and to said deck holding said clew and said flap portion in close proximity to said deck.

Claims (12)

1. In combination, a sailboat that has a mast and a deck, and a fore-and-aft sail comprising a sheet of flexible material that is secured at its upper end to said mast and extends downward to said deck and is contoured to form a flap portion of a sufficient dimension to lie on the deck substantially its full fore-and-aft dimension when the sail is in the close-hauled position so as to prevent any substantial flow of air laterally under said sail from the windward side to the leeward side thereof, said sail being a jib that has first attachment means at its forward lower end for fastening a tack, second attachment means at the lower after end of said upright portion for fastening a jib sheet, and a third attachment means at the inboard after end of said flap portion for fastening an auxiliary line.

2. The combination that is defined in claim 1, wherein said flexible material includes a transparent panel located in said upright portion immediately above said flap portion.

3. A fore-and-aft rigged sailboat having a deck, a mast, a swivel on said deck aft of said mast, a boom connected at one end to said swivel, a mainsail connected at its forward edge to said mast and having its clew connected to the other end of said boom, said mainsail being contoured so as to have an upright portion extending from its upper end downward approximately to the level of said clew and a contiguous flap portion extending inwardly therefrom to a position lower than said boom to lie on said deck to prevent substantial flow of air laterally under the mainsail from the windward to the leeward side thereof when in the close-hauled position.

4. The fore-and-aft rigged sailboat that is defined in claim 3, wherein said flap portion has attachment means at its after end, and securing means are fastened to said attachment means for positioning said flap portion.

5. The fore-and-aft rigged sailboat that is defined in claim 3, wherein said mainsail has a transparent panel located in said upright portion.

6. A fore-and-aft rigged sailboat having a deck, a mast, a swivel on said deck aft of said mast, a boom connected at one end to said swivel, a mainsail connected at its forward edge to said mast and having its clew connected to the other end of said boom, said mainsail being contoured so as to have an upright portion extending from its upper end downward approximately to the level of said clew and a contiguous flap portion extending inwardly therefrom to lie on said deck to prevent substantial flow of air laterally under the mainsail from the windward to the leeward side thereof when in the close-hauled position, said flap portion having attachment means at its after end, a securing means fastened to said attachment means for positioning said flap portion, said attachment means comprising a sleeve extending along the after edge of said flap portion, and said securing means including a line passing through said sleeve.

7. The fore-and-aft rigged sailboat that is defined in claim 6, wherein said securing means also includes a pulley on the end of said boom, and a transverse traveller mounted on said sailboat, said line being connected at one end to said traveller by a clasp adapted to slide on said traveller, the other end of said line passing through said pulley for controlling the position of the mainsail.

8. The fore-and-aft rigged sailboat that is defined in claim 7, wherein a second pulley is mounted on said boom forward of the first pulley, and a tube extends lengthwise of said boom, and said line extends from said first pulley through said tube and said second pulley.

9. A fore-and-aft rigged sailboat having a deck, a mast, a sail connected at its apex to said mast and having a clew, said sail being contoured so as to have an upright portion extending from its upper end downward approximately to the level of said clew and a flap portion extending inwardly therefrom to lie on said deck to prevent substantIal flow of air laterally under the sail from the windward to the leeward side thereof when in the close-hauled position, first securing means connected to said clew, said flap portion having attachment means spaced from said clew at its inboard after end, and second securing means connected to said attachment means for fastening said flap portion with its inward edge on said deck.

10. The fore-and-aft rigged sailboat that is defined in claim 9, wherein said first and second securing means comprise lines releasably attached to said deck.

11. The fore-and-aft rigged sailboat that is defined in claim 9, wherein said sail has a transparent panel located in said upright portion.

12. A fore-and-aft rigged sailboat having a deck, a mast, a sail connected at its apex to said mast and having a clew, said sail being contoured so as to have an upright portion extending from its upper end downward approximately to the level of said clew and a flap portion extending inward therefrom and dimensioned to lie on said deck to prevent substantial flow of air laterally under the sail from the windward to the leeward side thereof when in the close-hauled position, said flap portion terminating at its after end at said clew, and securing means connected to said clew and to said deck holding said clew and said flap portion in close proximity to said deck.

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