US3807333A

US3807333A - Sailboat

Info

Publication number: US3807333A
Application number: US00318015A
Authority: US
Inventors: A Ross
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-12-26
Filing date: 1972-12-26
Publication date: 1974-04-30
Anticipated expiration: 1991-04-30

Abstract

Sailboat comprises propulsion unit which carries all the requisites for propulsion of the sailboat by wind force, and a carrying unit for the carrying of goods and passengers. The units are connected together in a manner such that the carrying unit is not subjected to the heeling angular displacement which results from propulsion by sail.

Description

United States Patent Ross Apr. 30, 1974 [54] SAILBOAT FOREIGN PATENTS oR APPLICATIONS 1 lnvemofl Abrilham ROSS, 1400 Tahiti 1,005,089 12/1951 France .1 114/91 Marina Del Rey, Calif. 93933 [22] Filed: Deg 26, 1972 Primary Examiher-Trygve M. Blix App]. N0.: 318,015

US. Cl 114/39, 114/91, 114/123 Int. Cl B63b 35/00, B63h 9/00 Field of Search 114/39, 91, 123

References Cited UNITED STATES PATENTS 12/1925 Thorburn .1 114/91 3/1928 Ostcn 114/123 Attorney, Agent, or Firm-Allan M. Shapiro [57] ABSTRACT Sailboat comprises propulsion unit which carries all the requisites for propulsion of the sailboat by wind force, and a carrying unit for the carrying of goods and passengers. The units are connected together in a manner such that the carrying unit is not subjected to the heeling angular displacement'which results from propulsion by sail.

3 Claims, 3 Drawing Figures SAILBOAT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is directed to a sailboat, and particularly to a sailboat wherein the unit arranged for the carrying of goods and passengers is not subjected to heeling angles.

2. Description of the Prior Art The sailboat is an ancient development having a long lineage. It has, since earliest times, evolved as a vessel for the carrying of goods and passengers to which is directly attached the requisites for propelling this vessel by wind force. These requisites include a sail, and the wind force upon the sail tends to tilt the vessel hull. Therefore, hulls for sailing vessels have been designed to produce a maximized righting moment. The righting moment is the force which tends to return the hull toward the upright position, when it is tilted away from the upright position by wind or wave force. The maximization of righting force is necessary in a sailboat to prevent the wind force from laying the sailboat over. Another effect of wind force is the sideways drift of the sailing vessel. To overcome this sideways drift, hull design, centerboards, and keels have been employed to maximize sideward resistance. With the use of the keel, the keel can be weighted to produce additional righting moment.

With this structure, when wind force acts laterally upon the sail, the entire structure heels. This heeling is uncomfortable to passengers and is sometimes detrimental to goods carried in the hull of the vessel. As a result of this, attempts have been made to permit the mast to heel farther than the hull so that the hull heels at a lesser angle than the mast. These attempts have not fully recognized the problem or its solution. The righting moment produced by heeling must be equal to the heeling force caused by the wind on the sail. Thus, when the hull supplies the entire righting moment, it cannot ride level, when there is a lateral wind force, because there is no righting moment with level riding. Thus, some heeling of the hull has been required in prior structures.

SUMMARY OF THE INVENTION In order to aid in the understanding of this invention, it can be stated in essentially summary form that it is directed to a sailboat. The sailboat comprises apropulsion unit, the propulsion unit having at least a mast for carrying a sail for propulsion, a flotation structure for providing a righting moment, and a keel for providing lateral resistance and additional righting moment. Pivotally mounted on the propulsion unit on a fore-and aft pivot axis is a carrying unit for carrying goods and/or passengers. The carrying unit provides some flotation, at least to support part of the load of the carrying unit and its contents.

Accordingly, it is an object of this invention to provide a sailboat in which the passengers are separated from the heeling resulting from wind force on the sail. It is another object to separate the propulsion structure of the sailboat from the part that carries passengers. It is yet another object to attach all of the elements necessary for sailboat propulsion to a propulsion unit and pivotally attach thereto a carrying unit for supporting and carrying the useful load of the sailboat. It is yet an other object to provide a propulsion unit which is pivotally attached to a carrying unit upon a longitudinal axis, with first and second floats on opposite sides of the axis and a weighted keel below the axis.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of the sailboat of this invention.

FIG. 2 is an enlarged side elevational view thereof, with the mast broken away.

FIG. 3 is a stern view of the sailboat, as shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The sailboat of this invention is generally indicated at 10 in FIGS. 1, 2 and 3. Sailboat 10 is comprised of two units. Carrying unit 12 is in suitable form for carrying cargo and passengers and for providing at least some of the buoyancy necessary for supporting that load. It preferably resembles the traditional hull, as shown. It has a fore and aft axis defined by shafts l4 and 16. Car rying unit 12 is described in more detail below.

Propulsion unit 18 has three principal members. Mast 20 extends upward and supports one or more conventional sails. The rig of the sails can be of any of the well-known rigs, and, for the mast illustrated, a Marconi rig would be expected. However, the particular rig of the sails is unimportant to the principles of this invention and, thus, the mast 20 can be used to support sails in any conventional rig. For ease and clarity of illustration, the sails are not shown in the drawings. Mast 20 is supported in an upright position by means of

stays

22, 24 and 26, which are secured to the mast at their upper ends and are preferably secured to other portions of the propulsion unit at their lower ends.

The propulsion unit 18 also includes

floats

28 and 30. Furthermore, propulsion unit 18 includes keel 32. The three assemblies of propulsion unit 18, i.e., mast 20 with its sails,

floats

28 and 30, and keel 32, are rigidly secured together by connector 34. Connector 34 is in the shape of a hoop or ring which carries a mast step 36 at its upper point into which mast 20 is seated. Connector 34 passes through and is connected to both of

floats

28 and 30 so that the floats provide a buoyant support for the propulsion unit. Finally, the lower portion of connector 34 passes beneath carrying unit 12 and carries keel 32 thereon.

In sailing, the force of the-wind upon the sail produces a force on mast 20, including a forward component for propulsion of the sailboat and usually includes a lateral component which produces heeling. Two righting moments are provided to counteract the wind force. First of all, keel 32 is a weighted keel, and heeling of the sailboat moves the keel to a position where it is not directly underneath the longitudinal center line or axis, but is to one side thereof. The gravity component which urges the weighted keel 32 to a point where it is below the longitudinal center line is a righting moment which tends to force the mast 20 to the upright position. Another righting moment for the propulsion unit is received from the differential flotation forces of

floats

28 and 30, as the propulsion unit heels. For example, if the wind is coming from the position of the viewer in FIG. 1, float 28 will be forced farther down into the water, and float 30 will rise somewhat farther out of the water as the mast 20 heels to the right, as seen in FIG. 3. The normal at-rest water line is indicated by water level 38 in FIGS. 2 and 3.

As the sailboat moves forward and the leeward float is thrust down (in this case, float 28) and the windward float is lifted, in addition to the differential buoyancy, a differential in forward drag is found. The float farther into the water has more drag than the one lifted. This tends to cause the sailboat to fall off the wind, or to self-steer in a direction which is not as close into the wind. To overcome this, rudders 40 and 42 are respectively secured to the rear of

floats

28 and 30. These rudders preferably are fixed and shaped so that the area of the rudder immersed in the water increases faster than the immersion of the float. This is accomplished by having the rudder longer from front to back at the top than it is at the bottom. Furthermore, the rotary effectiveness is further increased with immersion by having greater camber or twist at the top than at the bottom, with progressive increasing twist from bottom to top.

When the sailboat is viewed from the top, in the level condition of the propulsion unit with both floats equally immersed, there is a balance of moments around a vertical axis due to float drag. With heeling, the skin friction drag on the leeward float increases so that there is a moment tending to turn the sailboat downwind. However, due to these fixed rudders, there is a balancing steering moment due to immersion of the fixed rudders which causes the drag moment around the vertical axis to be neutralized.

As is conventional in sailboat practice, all underwater parts of the propulsion unit are designed to minimize forward drag and maximize lateral drag. For in creased stability, connector 44 can interconnect the floats on keel 32 toward the rear thereof. The flotation provided by the normal immersion of the floats in the water is about equal to the weight of the propulsion unit.

Forward arm 46 extends forward from keel 32 and extends upward to carry bearing 48 thereon. Bearing 48 is on the longitudinal axis of heeling of the propulsion unit 18 and receives shaft 14. Additionally, aft arm 50 extends rearwardly and carries bearing 52 thereon. Bearing 52 is also on the longitudinal axis of the propulsion unit and receives shaft 16.

Carrying unit 12 is of such height and of such shape that it is partially immersed in the water to cause water displacement. It is illustrated as being in conventional boat hull form and has an open top providing cockpit 54. Cockpit 54 has

seats

56 and 58 therein for passengers. The sailboat is illustrated as being a fairly small boat for the carrying of a few passengers or a small cargo with one sailor. However, the size of the sailboat in the drawings is merely illustrative, and principles of this invention can be employed with a sailing vessel of fairly large dimensions. Carrying unit 12 is of such dimensions that it has a righting moment of its own, when it may tilt in the water. Rotation about this righting moment is substantially on the fore and aft axis defined by shafts l4 and 16. Thus, the lateral force of wind or waves against carrying unit 12 and the unbalanced load within the carrying unit will not cause tipover of the carrying unit, as long as they stay within the tolerable limits.

Rudder 60 is mounted at the rear of the sailboat and is selectively movable on a vertical axis, as by manual control of tiller 62. Rudder 60 can be mounted either upon the propulsion unit or the carrying unit but, since the carrying unit rides substantially upright in the water and the sailor will be riding therein, it is more convenient to pivotally mount rudder 60 on the carrying unit, As illustrated, this is accomplished by having it pivotally mounted on the rear of shaft 16. With this mounting of the rudder 60 as substantially upright in the water, it is independent of heeling of the propulsion unit.

From the described structure, it is clear that, when underway, lateral force upon the sail on mast 20 causes a heeling force, while the floats and keel cause a righting moment. This causes the propulsion unit to heel on a longitudinal axis, and this axis is preferably a substantially longitudinal axis through

bearings

48 and 52. Since carrying unit 12 is also pivotally mounted upon its longitudinal axis of rolling, it is independent of heeling of the propulsion unit. While carrying unit 12 is subjected to local forces, such as wave forces, such are minor compared to the heeling due to sail forces and, thus, the carrying unit 12 rides upright. in order to minimize rotary interconnection of the propulsion unit and carrying unit along their common axis, carrying unit 12 has flotation substantially equal to its own weight and the average load it is expected to carry. This minimizes bearing loads to achieve the most satisfactory interrelationship.

While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

l. A sailboat comprising:

a propulsion unit, said propulsion unit having 'a longitudinal axis, said propulsion unit having a mast for carrying a sail, a keel, and flotation means for providing flotation for said propulsion unit, a connector substantially rigidly connecting together said mast, said keel, and said flotation means;

said flotation means of said propulsion unit comprising first and second floats, said first and second floats being laterally separated on opposite sides of said longitudinal axis of said propulsion unit and each of said floats being connected to said connector;

each of said floats having a fixed rudder secured on the after end thereof, each of said fixed rudders being directed rearwardly and toward said axis in a direction to cause a steering torque to overcome increased drag of one of said floats due to heeling and increased immersion in the water, each of said fixed rudders having compound curvature to provide increased torque with increased immersion so that, when lateral force acts on said mast, said propulsion unit heels with rotation being substantially on its longitudinal axis and a righting moment is produced-by increased immersion of one of said floats to limit heeling and a corrective steering torque is produced by increased immersion of said fixed rudder on said one of said floats; carrying unit, said carrying unit being boat-hullshaped to displace water when said sailboat is in water to produce flotation for said carrying unit, said carrying unit being positioned between said floats and over said keel, said carrying unit having the longitudinal axis, a manually-directable rudder movably mounted on said carrying unit for applying torque to said sailboat for controlling the course direction of said sailboat; and pivot means on the longitudinal axis on said propulsion unit and on the longitudinal axis on said carrying unit for pivotally interconnecting said propulsion unit and said carrying unit so that said propulsion unit can heel in response to sail forces and said carrying unit is substantially isolated from rotation of said propulsion unit about said axis.

2. The sailboat of claim 1 wherein:

a forward arm forms a part of said propulsion unit and extends forward of said carrying unit to the axis thereof, and an aft arm forms part of said propulsion unit and extends to the rear of said carrying unit at the axis thereof, there being bearings and shafts on said arms and on said carrying unit for rotary inter-engagement therebetween on said longitudinal axis.

3. The sailboat of claim 2 wherein:

said arms extend from said keel forward and aft to said axis.

Claims

1. A sailboat comprising: a propulsion unit, said propulsion unit having a longitudinal axis, said propulsion unit having a mast for carrying a sail, a keel, and flotation means for providing flotation for said propulsion unit, a connector substantially rigidly connecting together said mast, said keel, and said flotation means; said flotation means of said propulsion unit comprising first and second floats, said first and second floats being laterally separated on opposite sides of said longitudinal axis of said propulsion unit and each of said floats being connected to said connector; each of said floats having a fixed rudder secured on the after end thereof, each of said fixed rudders being directed rearwardly and toward said axis in a direction to cause a steering torque to overcome increased drag of one of said floats due to heeling and increased immersion in the water, each of said fixed rudders having compound curvature to provide increased torque with increased immersion so that, when lateral force acts on said mast, said propulsion unit heels with rotation being substantially on its longitudinal axis and a righting moment is produced by increased immersion of one of said floats to limit heeling and a corrective steering torque is produced by increased immersion of said fixed rudder on said one of said floats; a carrying unit, said carrying unit being boat-hull-shaped to displace water when said sailboat is in water to produce flotation for said carrying unit, said carrying unit being positioned between said floats and over said keel, said carrying unit having the longitudinal axis, a manuallydirectable rudder movably mounted on said carrying unit for applying torque to said sailboat for controlling the course direction of said sailboat; and pivot means on the longitudinal axis on said propulsion unit and on the longitudinal axis on said carrying unit for pivotally interconnecting said propulsion unit and said carrying unit so that said propulsion unit can heel in response to sail forces and said carrying unit is substantially isolated from rotation of said propulsion unit about said axis.

2. The sailboat of claim 1 wherein: a forward arm forms a part of said propulsion unit and extends forward of said carrying unit to the axis thereof, and an aft arm forms part of said propulsion unit and extends to the rear of said carrying unit at the axis thereof, there being bearings and shafts on said arms and on said carrying unit for rotary inter-engagement therebetween on said longitudinal axis.

3. The sailboat of claim 2 wherein: said arms extend from said keel forward and aft to said axis.