US3866558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mast for sailing yachts and method
Assignee: Individual
•
Filing: 1973-09-05
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Granted: 1975-02-18
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Expires: 1993-09-05
Abstract
Abstract Reduction of drag and wind resistance offered by a mast coupled with increased sail efficiency is achieved in a mast having a non-circular cross-sectional shape and a plurality of rows of projections on the surface on opposite sides thereof and on the front side thereof and extending substantially throughout the length of the mast. Air flow passing around the mast undergoes turbulence and separates from the mast as a turbulent boundary layer and reattaches to the sail in a manner whereby the detached air flow between the mast and the sail is significantly less than that achieved by conventional mast constructions. Reattachment of air flow on the mast is enhanced by forming the rear side of the mast with a wedge-shaped enlarged slot for receiving the luff edge of the sail permitting the sail greater movement to either side of the mast to permit the air to reattach to the sail at a point closer to the mast than has been accomplished with conventional mast constructions. Preferably, the projections are integrally formed on an adhesive tape of metal, cloth or plastic which, in turn, is adhered to the opposite sides and the front of the mast. Additionally, a T-shaped slot is formed in the front side of the mast for accommodating fittings for a spinnaker pole or sails.
Inventors
- 👤 Lars Rune Bergstrom
- 👤 Georg Sven Olof Ridder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:00
CPC Classifications
B; B63; B63B; B63B15/00; B63B15/0083
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
197 words
A mast for a sailing yacht or similar watercraft to be propelled by the lift effect by the wind on the sail; the mast comprising an elongated body having a front end and a rear end and means for attaching a sail to the rear end, and first means including individual projections on the leeward side of the mast and raised from the surface of the mast and distributed substantially throughout the length of the mast for causing air flowing around the mast to separate as a turbulent boundary layer to ultimately reduce unattached flow of air between the mast and the sail when the mast is in use, and wherein there is further included second means including individual projections positioned on the windward side of the mast and raised from the surface of the mast and distributed substantially throughout the length of the mast and wherein there is further included third means including individual projections on the front end of the mast and raised from the surface of the mast and distributed substantially throughout the length of the mast, said second and third means also being for use in creating a turbulent boundary layer as aforesaid.
Claim 2
Dependent Claim
197 words
A mast for a sailing yacht or similar watercraft to be propelled by the lift effect by the wind on the sail; the mast comprising an elongated body having a front end and a rear end and means for attaching a sail to the rear end, and first means including individual projections on the leeward side of the mast and raised from the surface of the mast and distributed substantially throughout the length of the mast for causing air flowing around the mast to separate as a turbulent boundary layer to ultimately reduce unattached flow of air between the mast and the sail when the mast is in use, and wherein there is further included second means including individual projections positioned on the windward side of the mast and raised from the surface of the mast and distributed substantially throughout the length of the mast and wherein there is further included third means including individual projections on the front end of the mast and raised from the surface of the mast and distributed substantially throughout the length of the mast, said second and third means also being for use in creating a turbulent boundary layer as aforesaid.
Claim 3
Dependent Claim
19 words
The mast defined in claim 1 wherein the front end of the mast has a generally elliptical surface shape.
Claim 4
Dependent Claim
21 words
The mast defined in claim 2 wherein the opposite sides of the mast are surface-shaped as opposed arcs of a circle.
Claim 5
Dependent Claim
47 words
The mast defined in claim 3 wherein the opposite sides of the mast adjacent the rear end converge towards the rear end of the mast as opposed arcs of a circle having a greater radius of curvature than the arcs on the opposite sides of the mast.
Claim 6
Dependent Claim
47 words
The mast defined in claim 4 wherein the radius of curvature of the opposite sides of the mast adjacent the rear end of the mast is less than the radius of curvature of the opposite side portions of the mast adjacent the front end of the mast.
Claim 7
Dependent Claim
30 words
The mast defined in claim 1 wherein said projections are provided in a plurality of rows extending generally at right angles to a diametrical plane taken transversely through the mast.
Claim 8
Dependent Claim
21 words
The mast defined in claim 1 wherein said projections extend approximately one to one-half millimeter from the surface of the mast.
Claim 9
Dependent Claim
49 words
The mast defined in claim 1 wherein said projections on the leeward and windward sides and on the front end of the mast are provided in a plurality of rows at each of the locations on the windward and leeward sides and on the front end of the mast.
Claim 10
Dependent Claim
75 words
The mast defined in claim 8 wherein the front end thereof has a generally elliptical shape and the opposite sides thereof at the midsection thereof are formed as opposed arcs of a circle and wherein the opposite sides thereof adjacent the rear end coverage towards the rear end thereof as opposed arcs of a circle having a greater radius of curvature than the arcs of the opposite sides of the mast at the mid-section thereof.
Claim 11
Dependent Claim
63 words
The mast defined in claim 9 wherein the rear end of the mast body has an elongated geneRally V-shaped slot therein for receiving the luff edge of an associated sail and for permitting the sail to move further to opposite sides of the mast to decrease unattached flow of the air between the mast and the sail when the mast is in use.
Claim 12
Dependent Claim
37 words
The mast defined in claim 10 wherein the front end of the mast has an elongated generally T-shaped slot formed therein substantially throughout for receiving fittings for attaching a spinnaker pole or other sails to the mast.
Claim 13
Dependent Claim
39 words
The mast defined in claim 11 wherein there are a plurality of tapes adhered to the opposite sides of the mast and to the front end of the mast respectively and wherein said projections are formed on the tapes.
Claim 14
Dependent Claim
180 words
A mast for a sailing yacht or similar watercraft to be propelled by the lift effect of the wind on the sail; the mast comprising an elongated body having a front end and a rear end and means for attaching a sail to the rear end, and first means on the leeward side of the mast and raised from the surface of the mast and distributed substantially throughout the length of the mast for causing air flowing around the mast to separate as a turbulent boundary layer to ultimately reduce unattached flow of air between the mast and the sail when the mast is in use, and wherein said means on the leeward side of the mast is raised from the surface of the mast and includes a plurality of projections on the surface of the mast distributed substantially throughout the leeward side of the mast and wherein there is further included an elongated tape adhered to the leeward side of the mast and extending substantially throughout the full length thereof and wherein said projections are formed on said tape.
Claim 15
Dependent Claim
180 words
A mast for a sailing yacht or similar watercraft to be propelled by the lift effect of the wind on the sail; the mast comprising an elongated body having a front end and a rear end and means for attaching a sail to the rear end, and first means on the leeward side of the mast and raised from the surface of the mast and distributed substantially throughout the length of the mast for causing air flowing around the mast to separate as a turbulent boundary layer to ultimately reduce unattached flow of air between the mast and the sail when the mast is in use, and wherein said means on the leeward side of the mast is raised from the surface of the mast and includes a plurality of projections on the surface of the mast distributed substantially throughout the leeward side of the mast and wherein there is further included an elongated tape adhered to the leeward side of the mast and extending substantially throughout the full length thereof and wherein said projections are formed on said tape.
Claim 16
Dependent Claim
120 words
A mast for a sailing yacht or similar watercraft to be propelled by the lift effect by the wind on the sail; the mast comprising an elongated body having a front end and a rear end and means for attaching a sail to the rear end, and means projecting from the leeward side of the mast for causing air flowing around the mast to separate as a turbulent boundary layer to ultimately reduce the unattached flow of air between the mast and the sail when the mast is in use, and wherein there is further included sheet material attached to the leeward side of the mast and wherein said means projecting from the mast is formed on the sheet material.
Claim 17
Dependent Claim
120 words
A mast for a sailing yacht or similar watercraft to be propelled by the lift effect by the wind on the sail; the mast comprising an elongated body having a front end and a rear end and means for attaching a sail to the rear end, and means projecting from the leeward side of the mast for causing air flowing around the mast to separate as a turbulent boundary layer to ultimately reduce the unattached flow of air between the mast and the sail when the mast is in use, and wherein there is further included sheet material attached to the leeward side of the mast and wherein said means projecting from the mast is formed on the sheet material.
Claim 18
Dependent Claim
36 words
The mast defined in claim 14 wherein said means projecting from the mast is located rearwardly of the mid-section of the mast measured between the opposite sides of the mast at the widest width dimension thereof.
Claim 19
Dependent Claim
31 words
The mast defined in claim 14 wherein there is further included second means projecting from the front end of the mast for use in forming the said turbulent boundary layer aforesaid.
Claim 20
Dependent Claim
131 words
A mast for a sailing yacht or similar watercraft to be propelled by the lift effect by the wind on the sail; the mast comprising an elongated body having a front end and a rear end and means for attaching a sail to the rear end, and means projecting from the leeward side of the mast for causing air flowing around the mast to separate as a turbulent boundary layer to ultimately reduce the unattached flow of air between the mast and the sail when the mast is in use, and wherein said means projecting from the mast includes at least two rows of projections distributed along the longitudinal dimension of the mast with the projections in one of the rows being staggered relative to the projections in the other row.
Claim 21
Dependent Claim
131 words
A mast for a sailing yacht or similar watercraft to be propelled by the lift effect by the wind on the sail; the mast comprising an elongated body having a front end and a rear end and means for attaching a sail to the rear end, and means projecting from the leeward side of the mast for causing air flowing around the mast to separate as a turbulent boundary layer to ultimately reduce the unattached flow of air between the mast and the sail when the mast is in use, and wherein said means projecting from the mast includes at least two rows of projections distributed along the longitudinal dimension of the mast with the projections in one of the rows being staggered relative to the projections in the other row.
Claim 22
Dependent Claim
24 words
The mast defined in claim 17 wherein said projections extend from the surface of the mast a distance of approximately one and one-half millimeters.
Claim 23
Dependent Claim
36 words
The mast defined in claim 14 wherein the front end of the mast has a generally elliptical surface shape and wherein the opposite sides of the mast are surface shaped as opposed arcs of a circle.
Claim 24
Dependent Claim
78 words
The mast defined in claim 19 wherein the rear end of the mast has an elongated generally V-shaped recess through which the luff edge of the associated sail is connected to the mast, The V-shaped recess having a sufficiently large width greater than 45* for permitting the sail to move to extreme positions on opposite sides of the mast to increase unattached flow of the air between the mast and the sail when the mast is in use.
Claim 25
Independent Claim
103 words
A method of increasing attached air flow between a mast and a sail for a sailing yacht or similar wind propelled craft to reduce the resistance offered by the mast and to increase the sail efficiency, the step comprising providing projections along the surface of the mast at the leeward side thereof to cause air flowing about the mast to undergo turbulence and to detach from the mast as a turbulent boundary layer, and wherein said projections are provided by attaching an elongated tape-like sheet along the leeward side of the mast, the sheet having a plurality of projections distributed along its length.
Claim 26
Independent Claim
103 words
A method of increasing attached air flow between a mast and a sail for a sailing yacht or similar wind propelled craft to reduce the resistance offered by the mast and to increase the sail efficiency, the step comprising providing projections along the surface of the mast at the leeward side thereof to cause air flowing about the mast to undergo turbulence and to detach from the mast as a turbulent boundary layer, and wherein said projections are provided by attaching an elongated tape-like sheet along the leeward side of the mast, the sheet having a plurality of projections distributed along its length.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |