United States Patent 3841251

This specification discloses a catamaran sailboat including a hull on which a mast having the configuration of an airfoil is pivotally mounted. The hull itself offers minimal drag, comprising an articulated pair of planing floats, each of which has a leeboard associated with it to provide adequate lateral resistance. In use, the hull pivots about the leeward float, which remains substantially parallel to the surface of the water, even though the windward float may elevate sufficiently to clear the water.

Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
114/102.19, 114/102.25, D12/304
International Classes:
B63B1/14; B63H9/04; B63H9/10; (IPC1-7): B63H9/00
Field of Search:
View Patent Images:
US Patent References:
3566819SAILING CRAFT1971-03-02Keddie
3057316Collapsible sailboat1962-10-09Hansen

Primary Examiner:
Blix, Trygve M.
Assistant Examiner:
Goldstein, Stuart M.
What is claimed is

1. In a sailboat,

2. The sailboat of claim 1 in which the floats are planing floats.

3. The sailboat of claim 1 including a leeboard and a rudder on the outer perimeter of each side of said deck.

4. The sailboat of claim 3 in which the aft portion of the deck takes the form of deck extensions and the rudders are mounted on said extensions.

5. In a sailboat,

6. The sailboat of claim 5 including a leeboard and a rudder on the outer perimeter of each side of said deck.

7. The sailboat of claim 6 in which the aft portion of the deck takes the form of deck extensions and the rudders are mounted on said extensions.

The present invention relates to sailboats. It is concerned primarily with a novel construction and mechanism whereby maximum speed is achieved from wind power.

At the present time the principal factors limiting the speed of sailboats are the power obtainable from the sail and the water resistance of the hull. Thus, the wetted surface of the hull has considerable influence on the top speed of such a vessel. The present invention provides a sailboat structure offering minimal hull resistance and deriving maximum driving power from the sail.


With the foregoing conditions in mind the present invention has in view the following objectives:

1. To provide, in a sailboat, a mast, batten and sail assembly which functions as an airfoil.

2. To rpovide, in a sailboat assembly of the type noted, a mast which is pivotally mounted at its lower end on the hull of a sailboat.

3. To provide, in a sailboat of the character aforesaid, a mast having an airfoil cross-section and battens each of which includes a rigid section and a flexible section.

4. To provide, in a sailboat of the kind described, a carriage which is mounted for transverse movement on the rear of the hull and to which lines extending from the ends of the battens are secured.

5. To provide, in a sailboat of the type noted, a tensioning device on the carriage for each of the lines extending to a batten and an electronic control for governing the tension generated by each such device.

6. To provide, in a sailboat of the character aforesaid, a boom having its front end affixed to the mast with the lower edge of the sail secured to the boom and a line extending from the aft end of the boom to a tensioning device on the carriage which is governed by the electronic control.

7. To provide, in a sailboat of the type noted, a hull having an articulated pair of floats; and

8. To provide, in a sailboat of the type noted, a hull having an articulated pair of planing floats, each float having a leeboard associated therewith.

Various other more detailed objects and advantages of the invention, such as arise in connection with carrying out the above ideas in a practical embodiment, will, in part, become apparent and, in part, be hereafter stated as the description of the invention proceeds.


The foregoing objects are achieved by providing a sailboat which includes a hull and a mast.

The hull comprises two articulated planing floats, each having a leeboard and a rudder associated therewith. A deck is pivotally bridged between the floats.

The mast is pivotally mounted on the forward portion of the hull, and has a slight rearward incline or tilt. the mast is of a cross-section which presents a contour in the shape of an airfoil. Connected to this mast and extending rearwardly therefrom are a plurality of battens arranged in spaced parallel relation. Each of these battens has a major aft rigid section and a minor forward flexible section. These battens are sewed into a sail having an aft edge, the contour of which is determined by the length of the battens. A boom is attached to the lower edge of the sail.

A carriage is mounted on the rear portion of the hull for transverse movement relative thereto. Mounted in this carriage are a plurality of individual tensioning devices, one for each batten and one for the boom. A line extends from each tensioning device to the aft end of a batten to which it is secured. Another line extends from a tensioning device to the aft end of the boom. The tensioning devices are governed by an electronic control on the boom which is programmed to cause the devices to provide the tension which maintains the sail substantially flat.

For a full and more complete understanding of the invention, reference may be had to the following description and the accompanyings wherein:

FIG. 1 is a perspective of a catamaran having a structure in accordance with the precepts of this invention.

FIG. 2 is a detailed section on an enlarged scale through the mast and a portion of the sail, being taken on the plane of the line 2--2 of FIG. 1.

FIG. 3 is a detailed view, mostly in elevation of the lower portion of the sail and the carriage, being taken on the plane of the line 3--3 of FIg. 1.

FIG. 4 is a detailed longitudinal section on an enlarged scale through the deck of the catamaran, being taken on the plane of the line 4--4 of FIG. 1.

FIG. 5 is a transverse section through the catamaran depicting the deck in a horizontal position, being taken on the plane of the line 5--5 of FIG. 1; and

FIG. 6 is a section similar to FIG. 5 illustrating the deck as tilted.


Referring now to the drawings wherein like reference characters denote corresponding elements throughout the several views and first more particularly, to FIG. 1, a catamaran is shown as including a hull comprising a pair of planing floats or pontoons 10 and 11 which support a deck 12. The latter is pivotally connected to the floats by pivots 13. The deck 12 is formed with a slot 14 at each side. A leeboard or so-called centerboard 15 is pivotally mounted on a pivot 16 in each slot 14, and a pair of interconnected rudders 50 are disposed aft on each side of the deck 12. It will also be observed from FIGS. 5 and 6 that a stabilizer strut 17 extends between the pivotal connections 13 of each pair of such connections, one at the forward end and one at the aft end. Each end of each stabilizer 17 is connected to a pivot 18. Thus as the deck 12 tilts, the floats 10 and 11 remain horizontal, the float 11 and its associated leeboard 15 and rudder 50 elevate and clear the water, and the float 10 (which engages the water) remains substantially parallel to the surface thereof regardless of the inclination of the deck 12. These actions assure efficient planing and the presentation of minimal wetted hull area.

A mast 19 of airfoil configuration (FIG. 2) may be of any material having the required proportions of strength and rigidity but is shown as being of plastic such as fiberglass. It presents a leading edge 20 and a trailing edge 21. This may be accomplished in any preferred manner such as by a pivot pin 22 which is anchored to the deck 12 and is rotatably received in the mast 19, or by a short pivot pin (not illustrated) which projects from the lower end of the mast 10 received in a bearing such as indicated at 23 (FIG. 1).

Extending forwardly from the deck 12 and centrally thereof, are a pair of diverging arms 24 which, when considered together, constitute a bowsprit. A pair of guy wires 25 have their lower ends secured to the free ends of the arms 24 and their upper ends secured to a fitting 26 carried by the mast 10 adjacent to its upper end.

A boom 27 has its forward end connected to the trailing edge 21 of the mast 10 at a distance spaced above deck 12. A sail 28 has its lower edge attached to the boom 27. The sail 28 has a rear edge 29 which is curved. A plurality of battens 30 are sewed to or embedded in the sail 28. The battens 30 are of different lengths as determined by curved edge 29 of sail 28. Thus each batten has its forward end connected to the mast 10 at its trailing edge 21 and extends to the curved sail edge 29. These battens are arranged in spaced parallel relation.

Each batten 30 comprises a rigid section and a flexible section. As shown in FIG. 2 a batten 30 includes a rigid section 31 which is preferrably of wood and which constitutes the major extent of the batten. A flexible section 32, which preferrably is of a flexible plastic, has its aft end connected to the rigid section 31 by an articulation or joint 33 and its forward end to the trailing edge 21 of the mast 19 by a pin 34.

Referring again to FIG. 1, the deck 12 is formed at its aft end with a recess 35 which presents a pair of deck extensions 36 (from which depend the rudders 50). Upstanding from each of these extensions 36 at the rear thereof is a bracket 37 having an ear 38 at each end of the upper edge thereof. A pair of arcuate rails 39 extend between the brackets 37 with each end portion of each rail being secured to an ear 38 of a bracket.

Referring now to FIG. 3 a carriage is designated generally by the reference numeral 40. It comprises a platform 41 from which depend a pair of hangers 42. Each of the latter has pivotally mounted therein a pair of rollers 43 and 44. Each of these pairs of rollers encompasses a rail 39 whereby the carriage 40 is imported with the capability of moving transversely of the hull on the rails 39.

Mounted in the platform 41 are a plurality of tensioning devices represented diagrammatically at 45. There is one of these devices 45 for each batten 30. There is also another tensioning device 46 for the boom 27. An electronic control shown diagrammatically at 47 governs the operation of the tensioning devices 45 and 46 to determine the tension which is to be applied thereby to a line now to be described.

A line 48 is pivoted for each batten 30 and tensioning device 45. Thus each line 48 extends from a device 45 to the aft end of a batten 30. Another line 49 has one end connected to the tensioning device 46 and its other to the aft end of the boom 27.


In operation, wind pressure on the sail 28 is transmitted through the mast 19 and deck 12 to the leeward leeboard 15. The resulting lateral reaction force on the leeboard causes the deck 12 to tilt, thereby withdrawing the windward float 11 and associated leeboard 15 and rudder 50 from the water, as illustrated in FIG. 6. However, the action of the stabilizer bar 17 on the articulated floats 10 and 11 maintains the float 10 level and facilitates efficient planing on that float with minimal wetted hull area.

Also during operation, the carriage 40 is moved on the rails 39 when it is desired to swing the sail 28 as in "tacking." The boom 27 may be grasped by a person on deck 12 for this purpose. As the mast 19 pivots, such movement is accommodated by the guy wires 25 in a well known manner. Thus one wire will be slightly stretched as the other is relaxed.

The electronic control 47 may be programmed so that the tension provided by the devices 45 will be effective to apply the most effective tension or stress to the outer ends of the battens 30.

This selected, optimized tension on the latter coupled with the fact that the aft sections of each batten is rigid results in the sail 28 remaining substantially flat throughout the major portion of its extent. Thus the mast 19, with its airfoil contour, and the sail 28, the major portion of which is flat, provide an overall airfoil effect which makes available the maximum forward thrust. This, combined with the minimal drag at high speeds exhibited by the instant articulated hull, results in a sailboat having outstanding speed characteristics, and by improved stability and handling characteristics at all speeds.

While a preferred specific embodiment is herein disclosed, it is to be clearly understood that the invention is not to be limited to the exact construction, mateials and mechanisms illustrated and described because the various modifications of these details may be provided in putting the invention into practice.