Sailboat keel

Claim 2

A keel structure for a sailboat lying below and affixed to the bottom of the canoe hull thereof, the structure extending downwardly a predetermined distance below the hull load waterline, being disposed between the forward and after ends of said waterline, terminating in a bottom surface convexly curved symmetrically about the longitudinal vertical center plane of the structure, having a minimum transverse width located in a first horizontal plane whose depth below said waterline is equal to 0.110 ± 0.040 times the length of said waterline and a maximum transverse width located in a second horizontal plane above said bottom surface whose depth from said waterline is equal to 0.152 ± 0.038 times the length of said waterline and whose vertical distance above the centerline of said bottom surface is equal to 0.01 ± 0.002 times said second named depth, the transverse width of the structure increasing in concave curvilinear fashion from said minimum width downwardly and outwardly to said maximum width, each pair of opposed curves of intersection with said structure of any horizontal plane, from the plane of minimum transverse width to the plane of maximum width, being oppositely convex, symmetrical and curving toward each other from opposed points of maximum extension from said longitudinal vertical center plane to points of mutual intersection at the forward and after ends of the structure, respectively, whereby said structure presents smooth concave boundaries extending both forward and aft of its maximum width.

Claim 3

The structure as claimed in claim 1 wherein the transverse cross section is constructed in accordance with Table 3 wherein G designates the maximum width of the structure on said second plane, z' designates the vertical distance between said first and second planes, and z" designates the horizontal distance of an arbitrary point along a lateral curve of the transverse cross section at maximum width from the longitudinal vertical center plane of said structure at various vertical distances z upward from said second plane, Table 3 being as follows: ______________________________________ ##STR7## ##STR8## ______________________________________ 0.0 1.00 0.1 0.90 0.2 0.82 0.4 0.69 0.6 0.60 0.8 0.55 1.0 0.52. ______________________________________

Claim 4

The structure as claimed in claim 2 wherein Y 1 designates the forward point of intersection of the opposed curves generated by intersection with said structure of said second plane, Y 2 designates the corresponding after point of intersection thereof, Y designates an arbitrary point along one of said curves, Y 1 Y 2 designates the curvilinear distance between Y 1 and Y 2 , Y 1 Y designates the curvilinear distance between Y 1 and Y, and y designates the horizontal distance of the point Y from the centerplane of the structure, Table 2 being as follows: ______________________________________ ##STR9## ##STR10## ______________________________________ 0.0125 0.064 0.0250 0.18 0.050 0.33 0.10 0.58 0.20 0.81 0.30 0.95 0.40 1.00 0.50 0.96 0.60 0.87 0.70 0.70 0.80 0.49 0.90 0.26 0.95 0.12 1.00 0.00. ______________________________________

Claim 5

The structure as claimed in claim 3 wherein each curve of intersection with said structure generated by said first plane is defined by Table 1 wherein H designates the maximum width of said structure at said plane, X 1 designates the forward point of intersection of said curves, X 2 designates the after point of intersection of said curves, X designates an arbitrary point on one of said curves, X 1 X 2 designates the curvilinear distance from X 1 and X 2 , X 1 X designates the curvilinear distance between X 1 and X and x designates the distance of the point X from the vertical longitudinal centerplane of the structure, Table 1 being as follows: ______________________________________ ##STR11## ##STR12## ______________________________________ 0.0125 0.25 0.0250 0.35 0.0500 0.48 0.1000 0.66 0.20 0.87 0.30 0.97 0.40 1.00 0.50 0.98 0.60 0.90 0.70 0.78 0.80 0.60 0.90 0.35 0.95 0.19 1.00 0.00. ______________________________________

Claim 6

The structure as claimed in claim 4 wherein said structure is of shallow draft, said bottom surface extending below the load waterline to a depth between 0.115 and 0.19 times the length of said waterline.

Claim 7

The structure as claimed in claim 4 wherein said bottom surface is curvilinear and generated by segments of circles.

Claim 8

The structure as claimed in claim 3 wherein said structure is of shallow draft, said bottom surface extending below the load waterline to a depth between 0.115 and 0.19 times the length of said waterline.

Claim 9

The structure as claimed in claim 3 wherein said bottom surface is curvilinear and generated by segments of circles.

Claim 10

The structure as claimed in claim 2 wherein said structure is of shallow draft, said bottom surface extending below the load waterline to a depth between 0.115 and 0.19 times the length of said waterline.

Claim 11

The structure as claimed in claim 1 wherein said structure is of shallow draft, said bottom surface extending below the load waterline to a depth between 0.115 and 0.19 times the length of said waterline.

Claim 12

The structure as claimed in claim 1 wherein said bottom surface is curvilinear and generated by segments of circles.