BOAT HULL
United States Patent 3800725
A boat hull having a forward axis, a bow, a stern, two sidewalls, a transom wall, and a bottom wall. The bottom wall is formed in three segments: a scoop segment, a dihedral segment, and a planar segment in that order from the bow. The segments merge into one another. The scoop segment provides a scoop of decreasing cross-section area extending downwardly and rearwardly toward the dihedral segment, which dihedral segment has a central dihedral angle opening toward the bottom. The segments are defined by two pairs of runner faces that form dihedral angles which open upwardly, and the scoop segment is additionally defined by a scoop face which interconnects the innermost members of the pairs of runner faces.
US Patent References:
High-speed watercraft
Vinten - March 1965 - 3175528
Four point planing type of speed boat hull
Canazzi - August 1962 - 3051115
Hull for speed boats
Royer - May 1929 - 1712281
High-speed watercraft
Vinten - March 1965 - 3175528
Four point planing type of speed boat hull
Canazzi - August 1962 - 3051115
Hull for speed boats
Royer - May 1929 - 1712281
Application Number:
05/346276
Publication Date:
04/02/1974
Filing Date:
03/30/1973
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
114/62, 114/288, 114/355
International Classes:
B63B1/04; B63B1/00; B63B1/06
Field of Search:
114/66.5R,66.5P,66.5S,61,56,65R,62 9/6,1R
Primary Examiner:
Reger, Duane A.
Assistant Examiner:
Reese, Randolph A.
Attorney, Agent or Firm:
Mon, Donald D.
Claims:
I claim
1. A boat hull having a longitudinal, forwardly-extending central axis, a vertical plane of symmetry in which the central axis lies, and theoretical base plane below the hull and normal to the plane of symmetry, said hull having a bow and stern, said hull comprising a pair of laterally spaced-apart sidewalls, a transom wall at the stern and a bottom wall, said walls being interconnected to form a fluid-tight construction, said bottom wall including a scoop segment, a dihedral segment, and a planar segment in that order from the bow, said segments merging into one another, and being defined by two paris of generally axially-extending runner faces, defining said segments, a scoop face additionally defining the scoop segment, each pair of runner faces meeting at a respective runner edge and forming a respective upwardly-opening dihedral angle between themselves, the outermost member of each pair of runner faces intersecting a respective sidewall and the innermost member of each pair intersecting the other innermost member in the planar segment and dihedral segment, the innermost members being interconnected by the scoop face in the scoop segment, the said dihedral angles at the runner edges increasing in size in the scoop segment and dihedral segment as the runner edges extend from the bow toward the stern, whereby in the scoop segment a tapering scoop is formed between the scoop face and the innermost of the runner faces, the cross-section area of the scoop between the edges, the innermost members and the scoop face decreasing as the scoop extends from the bow toward the stern, the innermost runner faces intersecting to form a central dihedral angle in the dihedral segment, which central dihedral angle opens downwardly and has a central edge on the plane of symmetry, and the innermost runner faces being substantially co-planar in the planar segment, the runner edges extending from an upper elevation near the bow to a lower elevation in the dihedral segment.
2. A boat hull according to claim 1 in which the scoop face extends from an upper elevation near the bow to a lower elevation adjacent to the dihedral segment, where it intersects the central edge of the central dihedral angle.
3. A boat hull according to claim 2 in which the scoop face is curved and faces convexly downward in the scoop segment.
4. A boat hull according to claim 2 in which the size of the central dihedral angle in the dihedral segment increases as it extends from the scoop segment to the planar segment.
5. A boat hull according to claim 4 in which the scoop face is curved and faces convexly downward in the scoop segment.
6. A boat hull according to claim 1 in which the base plane and the innermost of the runner faces are substantially coincident in the planar section, and in which the runner edges lie substantially in the base plane in the planar dihedral segments.
7. A boat hull according to claim 6 in which the scoop face extends from an upper elevation toward the bow to a lower elevation adjacent to the dihedral segment, where it intersects the central edge of the central dihedral angle.
8. A boat hull according to claim 7 in which the scoop face is curved and faces convexly downward in the scoop segment.
9. A boat hull according to claim 8 in which the size of the central dihedral angle in the dihedral segment increases as it extends from the scoop segment to the planar segment.
10. A boat hull according to claim 1 in which the intersection of the scoop face with a plane that is normal both to the base plane and to the plane of symmetry is a straight line.
11. A boat hull according to claim 10 in which the scoop face is curved and faces convexly downward in the scoop segment.
12. A boat hull according to claim 11 in which the outermost ones of the runner faces merge smoothly with their respective sidewalls at the bow.
13. A boat hull according to claim 12 in which the scoop segment terminates at a forwardly-projecting lip.
14. A boat hull according to claim 10 in which the scoop face extends from an upper elevation near the bow to a lower elevation adjacent to the dihedral segment, where it intersects the central edge of the central dihedral angle.
15. A boat hull according to claim 14 in which the size of the central dihedral angle in the dihedral segment increases as it extends from the scoop segment to the planar segment.
1. A boat hull having a longitudinal, forwardly-extending central axis, a vertical plane of symmetry in which the central axis lies, and theoretical base plane below the hull and normal to the plane of symmetry, said hull having a bow and stern, said hull comprising a pair of laterally spaced-apart sidewalls, a transom wall at the stern and a bottom wall, said walls being interconnected to form a fluid-tight construction, said bottom wall including a scoop segment, a dihedral segment, and a planar segment in that order from the bow, said segments merging into one another, and being defined by two paris of generally axially-extending runner faces, defining said segments, a scoop face additionally defining the scoop segment, each pair of runner faces meeting at a respective runner edge and forming a respective upwardly-opening dihedral angle between themselves, the outermost member of each pair of runner faces intersecting a respective sidewall and the innermost member of each pair intersecting the other innermost member in the planar segment and dihedral segment, the innermost members being interconnected by the scoop face in the scoop segment, the said dihedral angles at the runner edges increasing in size in the scoop segment and dihedral segment as the runner edges extend from the bow toward the stern, whereby in the scoop segment a tapering scoop is formed between the scoop face and the innermost of the runner faces, the cross-section area of the scoop between the edges, the innermost members and the scoop face decreasing as the scoop extends from the bow toward the stern, the innermost runner faces intersecting to form a central dihedral angle in the dihedral segment, which central dihedral angle opens downwardly and has a central edge on the plane of symmetry, and the innermost runner faces being substantially co-planar in the planar segment, the runner edges extending from an upper elevation near the bow to a lower elevation in the dihedral segment.
2. A boat hull according to claim 1 in which the scoop face extends from an upper elevation near the bow to a lower elevation adjacent to the dihedral segment, where it intersects the central edge of the central dihedral angle.
3. A boat hull according to claim 2 in which the scoop face is curved and faces convexly downward in the scoop segment.
4. A boat hull according to claim 2 in which the size of the central dihedral angle in the dihedral segment increases as it extends from the scoop segment to the planar segment.
5. A boat hull according to claim 4 in which the scoop face is curved and faces convexly downward in the scoop segment.
6. A boat hull according to claim 1 in which the base plane and the innermost of the runner faces are substantially coincident in the planar section, and in which the runner edges lie substantially in the base plane in the planar dihedral segments.
7. A boat hull according to claim 6 in which the scoop face extends from an upper elevation toward the bow to a lower elevation adjacent to the dihedral segment, where it intersects the central edge of the central dihedral angle.
8. A boat hull according to claim 7 in which the scoop face is curved and faces convexly downward in the scoop segment.
9. A boat hull according to claim 8 in which the size of the central dihedral angle in the dihedral segment increases as it extends from the scoop segment to the planar segment.
10. A boat hull according to claim 1 in which the intersection of the scoop face with a plane that is normal both to the base plane and to the plane of symmetry is a straight line.
11. A boat hull according to claim 10 in which the scoop face is curved and faces convexly downward in the scoop segment.
12. A boat hull according to claim 11 in which the outermost ones of the runner faces merge smoothly with their respective sidewalls at the bow.
13. A boat hull according to claim 12 in which the scoop segment terminates at a forwardly-projecting lip.
14. A boat hull according to claim 10 in which the scoop face extends from an upper elevation near the bow to a lower elevation adjacent to the dihedral segment, where it intersects the central edge of the central dihedral angle.
15. A boat hull according to claim 14 in which the size of the central dihedral angle in the dihedral segment increases as it extends from the scoop segment to the planar segment.
Description:
This invention relates to a boat hull.
It is an objective in most boat hulls to provide as much capacity for forward speed as possible within the envelope prescribed by the general objectives of the boat. It is obvious that very high speed boats can be built but which have no substantial family utility, while boats can be built which can accommodate many persons and supplies but which are quite slow. It is an object of this invention to provide a boat which can be occupied by many persons, and which has an outer envelope which is appreciably larger than conventional boats capable of attaining like speeds. For example, a boat according to this invention has been made with an overall length of approximately 23 feet, a beam of 8 feet, a deck height above water approximately 11/2 feet and a cabin having a height above water of about 7 feet which can attain velocities as high as about 60 miles per hour with an inboard engine having a rated output of 400 horsepower. This is a significantly higher speed than can be attained with other boats utilizing the same power plant and with other boats having such a commodious envelope.
A boat hull according to this invention has a forward axis, a bow, a stern, sidewalls, a transom wall and a bottom wall. The bottom wall is formed in three segments: a scoop segment, a dihedral segment and a planar segment in that order from the bow, which segments merge into one another. The scoop segment provides a scoop of decreasing cross-section area extending rearwardly toward the dihedral segment, which dihedral segment has a central dihedral angle opening toward the bottom. The dihedral segment and scoop segment are defined by two pairs of runner faces which form two dihedral angles which open upwardly, and the scoop segment is additionally defined by a downwardly and rearwardly extending scoop face which interconnects the innermost members of the pairs of runner faces.
According to a preferred but optional feature of the invention, the scoop face is curved and faces convexly downward in the scoop segment as it extends downwardly and rearwardly.
According to another preferred but optional feature of the invention, the innermost of the runner faces are substantially coincident and coplanar in the planar section.
The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings in which:
FIG. 1 is a bottom view of the presently preferred embodiment of a hull according to the invention;
FIG. 2 is a side elevation taken at the bottom of FIG. 1;
FIG. 3 is a front elevation of the hull in FIG. 1;
FIGS. 4, 5, 6, 7, 8 and 9 are cross-sections taken at lines 4--4, 5--5, 6--6, 7--7, 8--8 and 9--9 respectively of FIG. 1, all except FIG. 5 being simplified to eliminate structure and to show only the outside envelope of the hull structure;
FIG. 10 is a rear elevation of the boat taken at line 10--10 of FIG. 1;
FIG. 11 is an axial vertical cross-section taken at line 11--11 in FIGS. 1 and 12; and
FIG. 12 is a top view of the envelope construction of FIG. 1 with all structure except the ribs and stringers removed for purposes of illustration.
The boat hull 20 is shown in FIG. 1. Because the invention essentially resides in the "skin" or "envelope" configuration of the hull, the details of construction such as reinforcers, strengtheners, stringers, cabin structure and the like have been largely eliminated from the drawings. Because the shape of the hull is derived entirely from the shape of the ribs, and the hull shape is shown for various stations in the Figs., the other details of construction are omitted. Persons skilled in the art will recognize that internal bracing and reinforcement must be provided to withstand the forces encountered by boats such as this when buffeted from the front or side or when operating at expected velocities, and that additional structure such as cabins will be provided for the user's convenience. Suffice it to say that the boat whose basic dimensions were given above and which will further be described below has been successfully made of 1/4 inch wall thickness marine grade plywood brought against and attached to ribs stationed at sections 4--4, 5--5, 6--6, 7--7, 8--8 and 9--9. The drawings show the outer skin configuration, which is greater than the corresponding rib dimension by 1/4 inch. For convenience, the rib dimensions are given in the drawings and tables. Because an actual boat has been successfully built from these rib dimensions, the accompanying specification of dimensions will constitute an adequate disclosure for a person skilled in the art to make the boat. The dimensions can be scaled up or down to give a boat of a different size, and the principles of the invention can be applied to boats of different proportions, still having the segments and other features defined herein, and being within the scope of the invention.
The boat hull 20 has a bow 21, a stern 22 and longitudinal forwardly extending central axis 23. A vertical plane of symmetry 24 constitutes the plane of FIG. 11 and is exemplified by section line 11--11 in FIG. 12. This plane of symmetry includes the central axis 23 and is normal to a theoretical base plane 25. The base plane lies in the plane of FIG. 1. The intersection of the plane of symmetry and the base plane show in FIGS. 3 and 11. Certain dimensions will be referred to this base plane.
The hull has a lip 26 which projects forwardly of a datum point at the bow, and has a transom wall 27 at the stern. The transom wall may slope upwardly and rearwardly and be substantially planar. The hull also includes a pair of laterally spaced apart sidewalls 28, 29 which slope upwardly and outwardly relative to the water line. An exemplary water line 30 is shown for a normally weighted completed and occupied boat according to this invention. In a boat built according to the example herein, the water line is approximately 12 inches above the base plane when the boat is floating motionless and lightly loaded in the water, with the engine and all propulsion equipment installed.
The hull also has a bottom wall 31. The bottom wall is divided functionally into three segments: a scoop 32, a dihedral segment 33 and a planar segment 34 in that order from the bow, which segments merge into one another as shown. These segments are defined by two pairs of runner faces: a first pair of runner faces 35, 36 and a second pair of runner faces 37, 38. Runner faces 35 and 38 are sometimes called the outermost members of the pairs of runner faces, and runner faces 36 and 37 are sometimes called the innermost members of these pairs. The first and second pairs of runner faces form respective upwardly opening dihedral angles 40, 41. These meet at respective runner edges 42, 43 (see FIGS. 3 and 5) which runner edges extend from near the bow to near the stern, descending in elevation from near the bow to the elevation of the base plane slightly forward of the intersection of the scope segment and dihedral segment. They lie substantially in the base plane in the dihedral segment and planar segment. The runner edges extend substantially parallel to the central plane of symmetry 24 and to each other. The walls are interconnected to form a fluid-tight construction.
The outermost ones of the runner faces form an angle with the vertical which increases as they extend from near the bow to near the stern. The sidewalls and respective outermost runner faces merge into a relatively smooth continuous structure at about the point denoted 44 in FIG. 1. This gives a graceful appearance to the craft, as does the parallelism of the runner edges.
The innermost ones of the runner faces 37 and 38 also form respective angles with the vertical which angles increase as they extend toward the rear from the bow so that the upwardly facing dihedral angles 40 and 41 increase in size as the dihedral angles progress rearwardly. The size continues to increase until near the junction of the dihedral and planar segments, at which location runner faces 37 and 36 are substantially coplanar and coincident to form the substantially planar segment.
In the dihedral segment, the innermost ones of the runner faces 36 and 37 form a central dihedral angle 45 with a central edge 46. The central dihedral angle 45 opens and faces downwardly. Edge 46 slopes downwardly and rearwardly to the planar segment (see FIG. 11).
The planar segment and the dihedral segment are fully defined by the runner faces. The scoop segment is partially defined by the runner faces and additionally by the scoop face. The scoop face exists to provide a tapering scoop 50 which has an open cross-section (see FIG. 4) defined as the area enclosed by a line extending horizontally between runner edges 42 and 43 and defined by the innermost runner faces 36 and 37 and by the scoop face 51. The cross-section area of the scoop decreases as it extends from the bow toward the stern. Its width measured along the horizontal line does not change. The scoop face extends rearwardly and downwardly and preferably but not necessarily forms a convex face that faces convexly downward into the scoop.
The general curvature of the scoop face is shown in FIG. 11. Instead of being convex it could be concave, straight or of curvature compounded of concave, convex or straight, or any combination of these. However the illustrated scoop face with the substantially greater angle of incident facing fowardly at the front than at the rear appears to give the hull better lift when passing through the water. The central edge 46 is substantially a continuation of the scoop face in the cross-section location of FIG. 1 (see FIG. 11). The scoop face extends from an upper elevation toward the bow to a lower elevation adjacent to the dihedral segment, where it intersects the central edge of the central dihedral angle. Its intersection with a plane that is normal to both the base plane and the plane of symmetry is a straight line. This plane is the plane of FIGS. 4 and 5, and of planes parallel to the planes of these Figs. The said straight line is best shown in FIGS. 4 and 5.
In FIG. 5 there are shown some schematic details of the actual construction of the hull. At each of the sections, a rib 55 (bulkhead) is formed with an outer boundary 56 having a shape which differs from the desired outer skin construction of the hull by the thickness of the material of which the skin is built. For example if the material is 1/4 inch plywood the dimension will be 1/4 inch less. Such ribs might be 1 inch thick wood to which the skin is attached by screws or other means. For longitudinal strength, stringers 57, 58, 59, 60, 61, 62, 63 and 64 pass through cut-outs in the ribs and are attached to the ribs. The skin material is fastened to the stringers as well as to the ribs. This is a conventional method of constructing a boat, and will be understood by persons skilled in the art. Other structures such as cabins, engine supports and the like will be built onto the resulting construction. The particular details of internal bracing and the like are not pertinent to this invention.
The bottom wall may be modified to provide a shaft tunnel 65, and an engine 66 may be mounted on an engine support 67 mounted to the hull for turning a propeller 68 mounted to a shaft 69 that passes through the tunnel, all in accordance with known techniques. Steering means such as a rudder 70 will of course be supplied.
It has been found desirable to direct the shaft tunnel downwardly at an angle of approximately 20° relative to the base plane.
In operation it appears that the scoop laterally stabilizes the boat by compressing air into it from both sides by virtue of its pressure against runner faces 36 and 37. The scoop face itself reacts with the air stream and drives the bow upwardly. The scoop directs a substantial body of air into the central dihedral angle, this dihedral segment serving both to stabilize the boat laterally and to trap the air beneath the hull to cause the boat to plane out of the water. Its shape tends to trap the air and to feed it directly and symmetrically to the planar segment, where further planing of the hull occurs. It has been found that this boat substantially raises to its planing position at about 10 miles per hour and is very stable in its operation.
The following is a set of dimensions which was utilized in constructing this boat the reference being had to the various ones of the figures to locate the dimensions.
These dimensions are in feet and inches. They are the rib dimensions, except where overall hull dimensions are given. To obtain hull dimensions, the thickness of the skin material must be added. Similar letters used at various rib stations relate to the same dimension of the respective stations.
TABLE OF DIMENSIONS
END VIEW AT LINE 3--3 IN FIG. 1 (SEE FIG. 3) 4" FORWARD OF DATUM POINT CC: 3'6" N: 11/2" R: 3'10" AT SECTION 4--4 (RIB 1), 4'6" ASTERN OF DATUM POINT R: 1'101/2" Q: 7'21/2" S: 1'11" EE: 9" CC: 1'6" DD: 3'9" V: 1'101/2" GG: 1'8" W: 3'71/2" AT SECTION 5--5 (RIB 2), 7'6" ASTERN OF DATUM POINT R: 1' W: 4' S: 2' Q: 7'10" CC: 6" EE: 9" DD: 3'9" V: 1' AT SECTION 6--6 (RIB 3), 10'6" ASTERN OF DATUM POINT R: 7' W: 4' S: 2' Q: 7'6" DD: 3'9" EE: 9" V: 7" GG: 1' AT SECTION 7--7 (RIB 4), 13'6" ASTERN OF DATUM POINT R: 31/2" W: 4' 8--8 (RIB 5), 16'6" ASTERN OF DATUM POINT DD: 3'9" Q: 7' V: 6" EE: 9" W: 3'10" GG: 1' AT SECTION 9--9 (RIB 6), 19' ASTERN OF DATUM POINT DD: 3'9" Q: 6'9" V: 6" EE: 9" W: 3'8" GG: 1' END VIEW AT LINE 10--10 IN FIG. 1 (SEE FIG. 10), 21' ASTERN OF DATUM POINT Q: 6'6" FF: 3'71/2" W: 3'9" MISCELLANEOUS DIMENSIONS HH: 4" D: 3' J: 6' JJ: 6' E: 3' K: 4'6" A: 4'6" F: 2'6" B: 3' G: 2' C: 3' H: 10'6"
this invention provides a very fast and stable boat which corners well. In fact in cornering it scarcely tips but remains quite flat and is able to achieve much greater velocities with the same power plant than more conventional boats constructed according to other designs.
This invention is not to be limited by the embodiment shown in the drawings and described in the description which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.
It is an objective in most boat hulls to provide as much capacity for forward speed as possible within the envelope prescribed by the general objectives of the boat. It is obvious that very high speed boats can be built but which have no substantial family utility, while boats can be built which can accommodate many persons and supplies but which are quite slow. It is an object of this invention to provide a boat which can be occupied by many persons, and which has an outer envelope which is appreciably larger than conventional boats capable of attaining like speeds. For example, a boat according to this invention has been made with an overall length of approximately 23 feet, a beam of 8 feet, a deck height above water approximately 11/2 feet and a cabin having a height above water of about 7 feet which can attain velocities as high as about 60 miles per hour with an inboard engine having a rated output of 400 horsepower. This is a significantly higher speed than can be attained with other boats utilizing the same power plant and with other boats having such a commodious envelope.
A boat hull according to this invention has a forward axis, a bow, a stern, sidewalls, a transom wall and a bottom wall. The bottom wall is formed in three segments: a scoop segment, a dihedral segment and a planar segment in that order from the bow, which segments merge into one another. The scoop segment provides a scoop of decreasing cross-section area extending rearwardly toward the dihedral segment, which dihedral segment has a central dihedral angle opening toward the bottom. The dihedral segment and scoop segment are defined by two pairs of runner faces which form two dihedral angles which open upwardly, and the scoop segment is additionally defined by a downwardly and rearwardly extending scoop face which interconnects the innermost members of the pairs of runner faces.
According to a preferred but optional feature of the invention, the scoop face is curved and faces convexly downward in the scoop segment as it extends downwardly and rearwardly.
According to another preferred but optional feature of the invention, the innermost of the runner faces are substantially coincident and coplanar in the planar section.
The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings in which:
FIG. 1 is a bottom view of the presently preferred embodiment of a hull according to the invention;
FIG. 2 is a side elevation taken at the bottom of FIG. 1;
FIG. 3 is a front elevation of the hull in FIG. 1;
FIGS. 4, 5, 6, 7, 8 and 9 are cross-sections taken at lines 4--4, 5--5, 6--6, 7--7, 8--8 and 9--9 respectively of FIG. 1, all except FIG. 5 being simplified to eliminate structure and to show only the outside envelope of the hull structure;
FIG. 10 is a rear elevation of the boat taken at line 10--10 of FIG. 1;
FIG. 11 is an axial vertical cross-section taken at line 11--11 in FIGS. 1 and 12; and
FIG. 12 is a top view of the envelope construction of FIG. 1 with all structure except the ribs and stringers removed for purposes of illustration.
The boat hull 20 is shown in FIG. 1. Because the invention essentially resides in the "skin" or "envelope" configuration of the hull, the details of construction such as reinforcers, strengtheners, stringers, cabin structure and the like have been largely eliminated from the drawings. Because the shape of the hull is derived entirely from the shape of the ribs, and the hull shape is shown for various stations in the Figs., the other details of construction are omitted. Persons skilled in the art will recognize that internal bracing and reinforcement must be provided to withstand the forces encountered by boats such as this when buffeted from the front or side or when operating at expected velocities, and that additional structure such as cabins will be provided for the user's convenience. Suffice it to say that the boat whose basic dimensions were given above and which will further be described below has been successfully made of 1/4 inch wall thickness marine grade plywood brought against and attached to ribs stationed at sections 4--4, 5--5, 6--6, 7--7, 8--8 and 9--9. The drawings show the outer skin configuration, which is greater than the corresponding rib dimension by 1/4 inch. For convenience, the rib dimensions are given in the drawings and tables. Because an actual boat has been successfully built from these rib dimensions, the accompanying specification of dimensions will constitute an adequate disclosure for a person skilled in the art to make the boat. The dimensions can be scaled up or down to give a boat of a different size, and the principles of the invention can be applied to boats of different proportions, still having the segments and other features defined herein, and being within the scope of the invention.
The boat hull 20 has a bow 21, a stern 22 and longitudinal forwardly extending central axis 23. A vertical plane of symmetry 24 constitutes the plane of FIG. 11 and is exemplified by section line 11--11 in FIG. 12. This plane of symmetry includes the central axis 23 and is normal to a theoretical base plane 25. The base plane lies in the plane of FIG. 1. The intersection of the plane of symmetry and the base plane show in FIGS. 3 and 11. Certain dimensions will be referred to this base plane.
The hull has a lip 26 which projects forwardly of a datum point at the bow, and has a transom wall 27 at the stern. The transom wall may slope upwardly and rearwardly and be substantially planar. The hull also includes a pair of laterally spaced apart sidewalls 28, 29 which slope upwardly and outwardly relative to the water line. An exemplary water line 30 is shown for a normally weighted completed and occupied boat according to this invention. In a boat built according to the example herein, the water line is approximately 12 inches above the base plane when the boat is floating motionless and lightly loaded in the water, with the engine and all propulsion equipment installed.
The hull also has a bottom wall 31. The bottom wall is divided functionally into three segments: a scoop 32, a dihedral segment 33 and a planar segment 34 in that order from the bow, which segments merge into one another as shown. These segments are defined by two pairs of runner faces: a first pair of runner faces 35, 36 and a second pair of runner faces 37, 38. Runner faces 35 and 38 are sometimes called the outermost members of the pairs of runner faces, and runner faces 36 and 37 are sometimes called the innermost members of these pairs. The first and second pairs of runner faces form respective upwardly opening dihedral angles 40, 41. These meet at respective runner edges 42, 43 (see FIGS. 3 and 5) which runner edges extend from near the bow to near the stern, descending in elevation from near the bow to the elevation of the base plane slightly forward of the intersection of the scope segment and dihedral segment. They lie substantially in the base plane in the dihedral segment and planar segment. The runner edges extend substantially parallel to the central plane of symmetry 24 and to each other. The walls are interconnected to form a fluid-tight construction.
The outermost ones of the runner faces form an angle with the vertical which increases as they extend from near the bow to near the stern. The sidewalls and respective outermost runner faces merge into a relatively smooth continuous structure at about the point denoted 44 in FIG. 1. This gives a graceful appearance to the craft, as does the parallelism of the runner edges.
The innermost ones of the runner faces 37 and 38 also form respective angles with the vertical which angles increase as they extend toward the rear from the bow so that the upwardly facing dihedral angles 40 and 41 increase in size as the dihedral angles progress rearwardly. The size continues to increase until near the junction of the dihedral and planar segments, at which location runner faces 37 and 36 are substantially coplanar and coincident to form the substantially planar segment.
In the dihedral segment, the innermost ones of the runner faces 36 and 37 form a central dihedral angle 45 with a central edge 46. The central dihedral angle 45 opens and faces downwardly. Edge 46 slopes downwardly and rearwardly to the planar segment (see FIG. 11).
The planar segment and the dihedral segment are fully defined by the runner faces. The scoop segment is partially defined by the runner faces and additionally by the scoop face. The scoop face exists to provide a tapering scoop 50 which has an open cross-section (see FIG. 4) defined as the area enclosed by a line extending horizontally between runner edges 42 and 43 and defined by the innermost runner faces 36 and 37 and by the scoop face 51. The cross-section area of the scoop decreases as it extends from the bow toward the stern. Its width measured along the horizontal line does not change. The scoop face extends rearwardly and downwardly and preferably but not necessarily forms a convex face that faces convexly downward into the scoop.
The general curvature of the scoop face is shown in FIG. 11. Instead of being convex it could be concave, straight or of curvature compounded of concave, convex or straight, or any combination of these. However the illustrated scoop face with the substantially greater angle of incident facing fowardly at the front than at the rear appears to give the hull better lift when passing through the water. The central edge 46 is substantially a continuation of the scoop face in the cross-section location of FIG. 1 (see FIG. 11). The scoop face extends from an upper elevation toward the bow to a lower elevation adjacent to the dihedral segment, where it intersects the central edge of the central dihedral angle. Its intersection with a plane that is normal to both the base plane and the plane of symmetry is a straight line. This plane is the plane of FIGS. 4 and 5, and of planes parallel to the planes of these Figs. The said straight line is best shown in FIGS. 4 and 5.
In FIG. 5 there are shown some schematic details of the actual construction of the hull. At each of the sections, a rib 55 (bulkhead) is formed with an outer boundary 56 having a shape which differs from the desired outer skin construction of the hull by the thickness of the material of which the skin is built. For example if the material is 1/4 inch plywood the dimension will be 1/4 inch less. Such ribs might be 1 inch thick wood to which the skin is attached by screws or other means. For longitudinal strength, stringers 57, 58, 59, 60, 61, 62, 63 and 64 pass through cut-outs in the ribs and are attached to the ribs. The skin material is fastened to the stringers as well as to the ribs. This is a conventional method of constructing a boat, and will be understood by persons skilled in the art. Other structures such as cabins, engine supports and the like will be built onto the resulting construction. The particular details of internal bracing and the like are not pertinent to this invention.
The bottom wall may be modified to provide a shaft tunnel 65, and an engine 66 may be mounted on an engine support 67 mounted to the hull for turning a propeller 68 mounted to a shaft 69 that passes through the tunnel, all in accordance with known techniques. Steering means such as a rudder 70 will of course be supplied.
It has been found desirable to direct the shaft tunnel downwardly at an angle of approximately 20° relative to the base plane.
In operation it appears that the scoop laterally stabilizes the boat by compressing air into it from both sides by virtue of its pressure against runner faces 36 and 37. The scoop face itself reacts with the air stream and drives the bow upwardly. The scoop directs a substantial body of air into the central dihedral angle, this dihedral segment serving both to stabilize the boat laterally and to trap the air beneath the hull to cause the boat to plane out of the water. Its shape tends to trap the air and to feed it directly and symmetrically to the planar segment, where further planing of the hull occurs. It has been found that this boat substantially raises to its planing position at about 10 miles per hour and is very stable in its operation.
The following is a set of dimensions which was utilized in constructing this boat the reference being had to the various ones of the figures to locate the dimensions.
These dimensions are in feet and inches. They are the rib dimensions, except where overall hull dimensions are given. To obtain hull dimensions, the thickness of the skin material must be added. Similar letters used at various rib stations relate to the same dimension of the respective stations.
TABLE OF DIMENSIONS
END VIEW AT LINE 3--3 IN FIG. 1 (SEE FIG. 3) 4" FORWARD OF DATUM POINT CC: 3'6" N: 11/2" R: 3'10" AT SECTION 4--4 (RIB 1), 4'6" ASTERN OF DATUM POINT R: 1'101/2" Q: 7'21/2" S: 1'11" EE: 9" CC: 1'6" DD: 3'9" V: 1'101/2" GG: 1'8" W: 3'71/2" AT SECTION 5--5 (RIB 2), 7'6" ASTERN OF DATUM POINT R: 1' W: 4' S: 2' Q: 7'10" CC: 6" EE: 9" DD: 3'9" V: 1' AT SECTION 6--6 (RIB 3), 10'6" ASTERN OF DATUM POINT R: 7' W: 4' S: 2' Q: 7'6" DD: 3'9" EE: 9" V: 7" GG: 1' AT SECTION 7--7 (RIB 4), 13'6" ASTERN OF DATUM POINT R: 31/2" W: 4' 8--8 (RIB 5), 16'6" ASTERN OF DATUM POINT DD: 3'9" Q: 7' V: 6" EE: 9" W: 3'10" GG: 1' AT SECTION 9--9 (RIB 6), 19' ASTERN OF DATUM POINT DD: 3'9" Q: 6'9" V: 6" EE: 9" W: 3'8" GG: 1' END VIEW AT LINE 10--10 IN FIG. 1 (SEE FIG. 10), 21' ASTERN OF DATUM POINT Q: 6'6" FF: 3'71/2" W: 3'9" MISCELLANEOUS DIMENSIONS HH: 4" D: 3' J: 6' JJ: 6' E: 3' K: 4'6" A: 4'6" F: 2'6" B: 3' G: 2' C: 3' H: 10'6"
this invention provides a very fast and stable boat which corners well. In fact in cornering it scarcely tips but remains quite flat and is able to achieve much greater velocities with the same power plant than more conventional boats constructed according to other designs.
This invention is not to be limited by the embodiment shown in the drawings and described in the description which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.