Watercraft hull having a constant flow tunnel and corresponding method

Abstract

A watercraft hull includes an opening in the body of the watercraft for defining a platform slot adjacent the stern. A flow tunnel is disposed within a lower hull portion and extends generally along the length of the lower hull portion to adjacent the platform slot. The ratio of the depth of the flow tunnel to the length of the flow tunnel is sufficiently small to permit the watercraft to remain buoyant in relatively shallow water. A directional keel extends along sides of the flow tunnel and outwardly from the lower hull portion for providing directional control to the watercraft.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/671,934 filed Apr. 15, 2005, of which is hereby incorporated herein in its entirety by reference.

FIELD OF THE INVENTION

The present invention relates to the field of watercraft, and more particularly, to a watercraft hull having a constant flow tunnel and accompanying propulsion system.

BACKGROUND OF THE INVENTION

A number of watercraft hull designs for improved water flow have employed flow tunnels, particularly straight tunnels with minimal divergence over their length. Current tunnel hull designs have achieved improvements in certain aspects of performance characteristics. Generally, such straight tunnels extend to the stern of the boat and feature deep tunnels of several feet at the stern to minimize water drag at high speeds. By displacing a substantial portion of the hull, these designs significantly reduce the volume of water contacting the hull. However, when such boats enter shallow water at slow speeds and become stationary, they must sink a substantial depth to allow water to fill the deep tunnel in the hull, thereby severely limiting their minimum stationary depth. The primary limitation of long and deep tunnel hull designs is a significant loss in buoyancy and increase in draft. Additionally, boats having long and deep tunnels lose significant hydrodynamic lift.

Although short and steep tunnel designs do not experience the same minimum depth restrictions as long and deep tunnel designs, the water flow through short and steep tunnels to the engine cooling intakes and propeller lacks the trajectory to permit the engine to be raised as high as desired. Additionally, water tends to bypass short and steep tunnel designs at high speeds, resulting in a loss of cooling water and propeller thrust and nonresponsive steering. U.S. Pat. No. 6,125,781 to White discloses such a tunnel extending a portion of the length of the lower hull.

SUMMARY OF THE INVENTION

In view of the foregoing background, it is therefore an object of the present invention to provide a watercraft with a hull for use in a variety of operating depths.

This and other objects, features, and advantages in accordance with the present invention are provided by a watercraft hull having a constant flow tunnel. The watercraft includes a bow, stern, lower hull, and an upper surface. The watercraft hull may include an opening in the body of the watercraft defining a platform slot aligned with the watercraft longitudinal axis from a first end to a second end adjacent the stern, and extending transverse to the watercraft longitudinal axis from the lower hull to the upper surface. The watercraft hull may further include a constant flow tunnel disposed within the lower hull having a first side, a second side, a first end and a second end adjacent the first end of the platform slot. The length of the tunnel between the first and second end may be substantially equal to the length of the lower hull along the watercraft longitudinal axis. The depth of the tunnel at the second end may be substantially less than the length of the tunnel.

The ratio of the depth of the tunnel to the length of the tunnel may be sufficiently small to permit the watercraft to remain buoyant in relatively shallow water. The depth-to-length ratio of the tunnel may be such that the watercraft may remain buoyant at depths of less than one foot, six inches, and four inches of water. The depth-to-length ratio may vary from 0.01 to 0.1, or further from 0.01 to 0.05.

The tunnel may feature negligible diversion from the first end to the second end.

A directional keel may extend along the first and second sides of the tunnel and outwardly from the lower hull for providing directional control to the watercraft.

The slope of the tunnel (or depth-to-length ratio) from the first end to the second end may approach the constant rising slope of water upon exiting from beneath the hull and beyond the stern. The constant rising slope of water upon exiting the hull, as well known to one of ordinary skill in the art, is approximately one to two inches per foot.

A constant flow tunnel propulsion system for the watercraft hull having the constant flow tunnel may include an adjustable platform positioned within the platform slot for supporting the watercraft engine, the adjustable platform having an adjustable height.

The directional keel may extend along the first and second sides of the tunnel from the first end to within a buffer distance of the second end, the buffer distance substantially less than the length of the tunnel.

The engine propeller and adjustable platform height may be commonly adjusted. The engine propeller may be adjusted such that the tunnel deflects water into the propeller and away from the mid-section of the engine. The engine propeller and adjustable platform height may be commonly adjusted by one of an electronic and hydraulic means. The adjustable platform may include a plate aligned with the engine main axis during normal watercraft propulsion and vertically adjusted within opposing slots within the insert slot. The adjustable platform may further include a locking mechanism for fixing the adjustable platform height.

A method is for making a constant flow tunnel propulsion system in the watercraft hull. The method may include forming an opening in the body of the watercraft defining a platform slot aligned with the watercraft longitudinal axis from a first end to a second end adjacent the stern, and extending transverse to the watercraft longitudinal axis from the lower hull to the upper surface. The method may further include forming a tunnel disposed within the lower hull having a first side, a second side, a first end and a second end adjacent the first end of the platform slot. The length of the tunnel between the first and second end may be substantially equal to the length of the lower hull along the watercraft longitudinal axis. The depth of the tunnel at the second end may be substantially less than the length of the tunnel. The method may further include forming an adjustable platform positioned within the platform slot for supporting the watercraft engine, the adjustable platform having an adjustable height.

Another embodiment may include an adjustable hull for a watercraft. The watercraft includes a bow, stern, bottom surface, upper surface, and an engine having a propeller for propelling the watercraft. The adjustable hull comprises an opening in the body of the watercraft for defining an insert slot aligned with the boat longitudinal axis from a first end to a second end, and extending transverse to the boat longitudinal axis from the bottom surface to the upper surface. The adjustable hull further comprises a hinge for rotatably securing an insert within the insert slot, and an adjustable platform positioned within the insert slot for supporting the watercraft engine, the adjustable platform having an adjustable height.

The hinge may rotatably secure the insert at the first end of the insert slot, and the second end of the insert slot may be coupled to the stern of the watercraft.

The insert may include a slit along a second end of the insert adjacent the second end of the insert slot, the slit adjacent the engine propeller.

The insert may cover a substantial portion of the insert slot, and may further take a triangular shape.

The insert may be rotated from a lower position aligned with the bottom surface of the watercraft to an upper position accommodating water flowing through the insert slot below the insert and out the back end of the watercraft above the bottom surface.

The insert and adjustable platform may be co-adjusted, and the insert and propeller may share a common alignment during adjustment. Such common alignment may include the insert aligned with a top portion of the engine propeller. The insert and adjustable platform height may be varied by one of electric and hydraulic means. The adjustable platform may include a plate adjusted within opposing sidewall slots of the insert slot. The adjustable platform may include a locking mechanism for fixing the adjustable platform height.

A method for making an adjustable hull for a watercraft, the watercraft comprising a bow, stern, bottom surface, upper surface, and an engine having a propeller for propelling the watercraft. The method for making the adjustable hull comprises forming an opening in the body of the watercraft for defining an insert slot aligned with the boat longitudinal axis from a first end to a second end, and extending transverse to the boat longitudinal axis from the bottom surface to the upper surface. The method further comprises forming a hinge for rotatably securing an insert within the insert slot, and forming an adjustable platform positioned within the insert slot for supporting the watercraft engine, the adjustable platform having an adjustable height. The method may further comprise rotatably securing the insert from a lower position aligned with the bottom surface of the watercraft to an upper position accommodating water flowing through the insert slot below the insert and out the back end of the watercraft above the bottom surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bottom perspective view of a watercraft hull having a constant flow tunnel in accordance with the present invention.

FIG. 2 is a bottom plan view of the watercraft with an adjustable hull having a constant flow tunnel shown in FIG. 1.

FIG. 3 is a side perspective view of a constant flow tunnel propulsion system in accordance with the present invention.

FIG. 4 is a side perspective view of the constant flow tunnel propulsion system shown in FIG. 3.

FIG. 5 is a bottom perspective view of a watercraft hull having a constant flow tunnel in accordance with the present invention.

FIG. 6 is a bottom perspective view of a watercraft with an adjustable watercraft hull in accordance with the present invention.

FIG. 7 is a top perspective view of a watercraft with an adjustable hull and the engine removed.

FIG. 8 is a partial rear plan view of the watercraft with an adjustable watercraft hull of FIG. 1.

FIG. 9 is a partial bottom perspective view of the watercraft with an adjustable watercraft hull of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

Referring to FIGS. 1-4, a watercraft hull 10 having a constant flow tunnel 12 is now described. The watercraft 14 includes a bow 16, stern 18, lower hull 20, and an upper surface 22. The watercraft 14 may include a left and right transom 90, 92. The watercraft may be a boat or any other water vehicle known to one of skill in the art having a hull and propelled by an externally mounted engine. The watercraft hull 10 may include an opening in the body of the watercraft defining a platform slot 24 aligned with the watercraft longitudinal axis 26 from a first end 28 to a second end 30 adjacent the stern 18, and extending transverse to the watercraft longitudinal axis from the lower hull 20 to the upper surface 22. The platform slot 24 may include opposing sidewalls 25, 27. In an exemplary embodiment, the width of the platform slot 24 at the second end 30 may be approximately 22¾″.

The watercraft hull 10 may further include a constant flow tunnel 12 disposed within the lower hull 20 having a first side 32, a second side 34, a first end 36 and a second end 38 adjacent the first end 28 of the platform slot 24. The tunnel 12 may include a slight-V bottom. The tunnel 12 may include a flat or smoothed bottom. The second end 38 of the flow tunnel 12 may be continuous with the first end 28 of the platform slot 24, thus permitting water to flow through the flow tunnel and through the platform slot before exiting at the stern.

The length of the tunnel 12 between the first and second end 36, 38 may be substantially equal to the length of the lower hull 20 along the watercraft longitudinal axis 26. The depth of the tunnel 12 at the second end 38 may be substantially less than the length of the tunnel. The tunnel 12 may be extended substantially the length of the lower hull 20 to accommodate water flow at high speeds. The tunnel 12 depth may rise linearly from the first end 36 to the second end 38. The tunnel 12 may rise gradually in depth from the first end 36 to the second end 38. The tunnel 12 depth may rise non-linearly from the first end 36 to the second end 38. The tunnel 12 may form a concave or convex profile from the first end 36 to the second end 38. In an exemplary embodiment, the depth of the second end 38 of the tunnel 12 is approximately 4 inches deep. In a further exemplary embodiment, the depth of the tunnel approximately 12 inches forward from the second end 38 of the tunnel is approximately 2 inches deep. The front end 36 of the tunnel 12 may be flush with the lower hull 16.

The ratio of the depth of the tunnel 12 to the length of the tunnel may be reduced to permit the watercraft 14 to remain buoyant in relatively shallow water. The depth-to-length ratio of the tunnel 12 may be adjusted such that the propeller 56 may be raised sufficiently high to permit the watercraft 14 to operate in shallow water without the propeller 56 hitting the bottom surface. Further, the depth-to-length ratio of the tunnel 12 may be adjusted so to permit the watercraft 14 to run at high speeds in rough water and engage in turning maneuvers during such conditions. The depth-to-length ratio of the tunnel 12 may be minimized so to maximize the watercraft 14 minimum stationary depth, while still maintaining a tunnel profile for directing water over the engine propeller 56, as described below. The depth-to-length ratio of the tunnel 12 may be such that the watercraft 14 may remain buoyant at depths of less than one foot, six inches, and four inches of water. The depth-to-length ratio may vary between 0.01 to 0.1, or further between 0.01 to 0.05. The slope of the tunnel (or depth-to-length ratio) from the first end 36 to the second end 38 may approach the constant rising slope of water upon exiting from beneath the hull 10 and beyond the stern 18. The constant rising slope of water upon exiting the hull 10, as well known to one of ordinary skill in the art, is approximately 1-2 inches per foot.

The tunnel 12 may feature negligible diversion from the first end 36 to the second end 38. The tunnel 12 sides 32, 34 and ends 36, 38 may take a substantially rectangular form. The tunnel 12 sides 32, 34 and ends 36, 38 may take the form of any four-sided shape known to one of skill in the art.

A separate tunnel extension piece 39 may be attached at the second end 38 of the tunnel 12. The tunnel extension piece 39 effectively extends the tunnel 12 to within a predetermined distance 41 of the front of the engine mid-section 60. The tunnel extension 39 may be attached to recessed areas 82, 84, and 86 in the lower hull 16. The tunnel extension piece 39 may be separately molded to the tunnel 12, and may maintain controlled constant water flow to the propeller 56 and cooling water intakes during initial acceleration, high speed operation, and directional maneuvering.

A directional keel 40, 42 may extend along the first and second sides 32, 34 of the tunnel 12 and outwardly from the lower hull 20 for providing directional control to the watercraft 14. The directional keels 40, 42 may effectively increase the depth of the tunnel 12 with minimal effect on the shallow water draft of the hull 10. The directional keel 40, 42 may include an outer rim 44, 46 for providing directional stability when the watercraft 14 is directed by a steering mechanism, as appreciated by one of skill in the art. In an exemplary embodiment, the tunnel depth at a location 80 approximately 12 inches short of the second end 38 may be approximately 2 inches, and location 80 may mark the location where the keel 40, 42 may stop. In an exemplary embodiment, the keel 40, 42 may extend below the lower hull 16 approximately 1½″, and may be approximately 1¼″ wide. In a further exemplary embodiment, the width of the tunnel 12 at the first end 36 between keel 40, 42 may be approximately 17½″. In a further exemplary embodiment, the width of the tunnel 12 at the second end 38 may be approximately 18½″.

The lower hull 20 of the watercraft 14 may include level exterior chines 47, 49 extending from the bow 16 to the stern 18. The entire lower hull 20 may remain below the water surface while fishing to block waves from entering below the hull, causing noise from slapping the hull 10.

A constant flow tunnel propulsion system 50 for the watercraft hull 10 having the constant flow tunnel 12 may include an adjustable platform 52 positioned within the platform slot 24 for supporting the watercraft engine 54, the adjustable platform having an adjustable height.

The directional keel 40, 42 may extend along the first and second sides 32, 34 of the tunnel 12 from the first end 36 to within a buffer distance 58 of the second end 38, the buffer distance substantially less than the length of the tunnel. The buffer distance 58 provides adequate space for the water flowing through the tunnel 12 to spread out upon entering the platform slot 24 and passing through the propeller 56, as discussed below.

The engine propeller 56 and adjustable platform 52 height may be commonly adjusted. The engine propeller 56 may be adjusted such that the tunnel 12 deflects water into the propeller 56 and away from the mid-section 60 of the engine 54. The engine propeller 56 and adjustable platform 52 height may be commonly adjusted by one of an electronic and hydraulic means 62. The tunnel 12 is sized such that the propeller 56 may be raised above the lower hull 20 in shallow water so to maintain a shallow draft, and maintain a constant water flow to the engine propeller and cooling water intake valve during shallow water acceleration. The adjustable platform 52 may include a plate 64 aligned with the engine main axis 66 during normal watercraft propulsion and vertically adjusted within opposing slots within the platform slot 24. The opposing slots may be positioned within opposing mount bars the mount bars secured to the interior sidewalls of the platform slot 24. The adjustable platform 52 may further include a locking mechanism 76 for fixing the adjustable platform height. The engine 54 may be securely coupled to the plate 64 by any method known to one of skill in the art so to facilitate common adjustment of the engine propeller 56 and the adjustment platform 52. For example, a plurality of fasteners may be passed through receiving apertures in the engine 54 and secured to the plate 64, thereby securing the engine to the adjustable platform 52. Although a plate 64 is illustratively disclosed, the adjustable platform 52 may include any structure known to one of skill in the art for facilitating coupling to the engine 54 for common vertical adjustment with the propeller 56 within the platform slot 24.

The lower hull 16 may have a left and right recessed area 91, 93 for the installation mechanically controlled stainless steel trim tabs. The trim tabs may be hinged at the front and can be lowered at the rear to improve initial acceleration. The area of the trim tab mounting is angled down from the front 93 to the rear 95 on the left side and the front 97 to the rear 99 on the right side. The downward angle of the trim tab mounting surface may be designed to control the boat at high speeds. In an exemplary embodiment, the downward slope toward the rear may be approximately ¼″.

A left chine line 71 intersects the left transom 90, the right chine line 73 intersects the right transom 92. In an exemplary embodiment, the left transom and right transom may each extend approximately 23 inches. The chines 71,73 facilitate shallow water fishing in suppressing lateral waves from striking the lower hull 16 and causing unusual sounds when passing through water, as fish are sensitive to water sounds or wave sounds slapping against a boat hull and may leave the area in response.

A method is for making a constant flow tunnel propulsion system 50 in the watercraft hull 10. The method may include forming an opening in the body of the watercraft defining a platform slot 24 aligned with the watercraft longitudinal axis 26 from a first end 28 to a second end 30 adjacent the stern 18, and extending transverse to the watercraft longitudinal axis from the lower hull 20 to the upper surface 22. The method may further include forming a tunnel 12 disposed within the lower hull 20 having a first side 32, a second side 34, a first end 36 and a second end 38 adjacent the first end 28 of the platform slot. The length of the tunnel 12 between the first and second end 36, 38 may be substantially equal to the length of the lower hull 20 along the watercraft longitudinal axis 26. The depth of the tunnel 12 at the second end 38 may be substantially less than the length of the tunnel. The method may further include forming an adjustable platform 52 positioned within the platform slot 24 for supporting the watercraft engine 54, the adjustable platform having an adjustable height.

Referring to FIGS. 5-9, another embodiment may include an adjustable hull 108 for a watercraft 110 is now described. The watercraft 110 includes a bow 112, stern 114, lower hull 116, upper surface 118, and an engine 144 having a propeller 146 for propelling the watercraft. The watercraft 110 may be a boat or any other watercraft having a lower hull and utilizing an externally-mounted engine with a propeller for propulsion.

The adjustable hull 108 includes an opening in the body of the watercraft 110 for defining an insert slot 120 aligned with the watercraft longitudinal axis 121 from a first end 123 to a second end 125 adjacent the stern 114, and extending transverse to the watercraft longitudinal axis from the lower hull 116 to the upper surface 118. The adjustable hull 108 further includes a hinge 124 for rotatably securing an insert 122 within the insert slot 120 at the first end 123, and an adjustable platform 131 positioned within the insert slot 120 for supporting the watercraft engine 144, the adjustable platform 131 having an adjustable height.

Although a hinge 124 may rotatably secure the insert 122 within the insert slot 120, any means known to one of ordinary skill in the art for rotatably securing the insert 122 within the insert 120 may be used.

Throughout its rotational range within the insert slot 120, the insert 122 may cover a substantial portion of the insert slot 120 to prevent water from entering the insert slot 120 above the insert 122. To aid in preventing water passing into the insert slot 120 above the insert 122, either side of the insert 122 along the insert slot 120 may include an outer lip in contact with the interior sidewalls 128, 130 of the insert slot 120. The insert 122 and insert slot 120 may each take a triangular shape.

Although the insert 122 is illustrated as rotatably secured within the insert slot 120 from the first end 123 to adjacent the stern 114, the insert may be rotatably secured between any two positions within the insert slot. Further, the insert 122 may only cover a portion of the insert slot 120.

The insert 122 may include a slit 126 along a second end 127 of the insert adjacent the second end 125 of the insert slot 120, the slit adjacent the engine propeller 146 to facilitate externally mounting the engine 144 within the insert slot 120. The slit 126 may take the form of the engine 144 mid-section cross-section adjacent the slit.

The insert 122 may be rotated from a lower position (FIG. 5) aligned with the lower hull 116 of the watercraft to an upper position (FIG. 9) accommodating water flowing through the insert slot 120 below the insert 122 and past the stern 114 of the watercraft 110 above the lower hull 116.

The insert 122, engine propeller 146 and adjustable platform 131 height within the insert slot 120 may be co-adjusted, and the insert 122 and engine propeller 146 may share a common alignment during such adjustment. Such common alignment may include the insert 122 aligned with a top portion of the engine propeller 146 to deflect water into the propeller and away from the mid-section of the engine to reduce unnecessary drag.

The adjustable platform 131 height within the insert slot 120 may be selectively adjusted. The insert 122 and engine 144 may be interconnected with the adjustable platform 131, causing the insert 122 and engine 144 to displace with the adjustable platform 131 within the insert slot 120. The adjustable platform 131 may include an aluminum plate. 133 aligned with the engine main axis during normal watercraft propulsion and coupled to vertical members the vertical members slidably received within slots of opposing mount bars 132, 134. The opposing mount bars 132, 134 may be secured to the interior sidewalls 128, 130 of the interior slot 120 by any method appreciated by one of skill in the art. A locking mechanism holds the aluminum plate 133 at a fixed height within the mounting bar slots and an electric or hydraulic means may vary the height of the aluminum plate 133 within the opposing mount bars 132, 134 slots. Fasteners 156, 158 may pass through the engine 144 frame and link bars 152, 154 coupled to the insert 122, before the fasteners secure to the aluminum plate 133, thus coupling the engine 144 and insert 122 to the adjustable platform 131. As a result, the insert 122, engine propeller 146 and adjustable platform 131 may be commonly adjusted, as mentioned above.

Each link bar 152, 154 may include an adjustment means for selectively adjusting the fixed distance between the insert 122 and adjustable platform 131, and thus the fixed alignment relationship between the insert and propeller 146. For example, to shift the fixed alignment of the insert 122 to a higher portion of the propeller 146, the adjustment means is adjusted so to shorten the distance between the insert and the adjustable platform 131.

Opposing mounting bars 132, 134 may be secured to the interior sidewalls 128, 130 of the insert slot 120 by any method appreciated by one of skill in the art. The adjustable platform 131 may include an aluminum plate 133, which may be slidably received within slots within the respective opposing mounting bars 132, 134. The adjustable platform may include a locking mechanism for fixing the adjustable platform height.

A method for making an adjustable hull 108 for a watercraft 110, the watercraft comprising a bow 112, stern 114, lower hull 116, upper surface 118, and an engine 144 having a propeller 146 for propelling the watercraft. The method for making the adjustable hull 108 comprises forming an opening in the body of the watercraft for defining an insert slot 120 aligned with the watercraft longitudinal axis 121 from a first end 123 to a second end 125, and extending transverse to the watercraft longitudinal axis from the lower hull 116 to the upper surface 118. The method further comprises forming a hinge 124 for rotatably securing an insert 122 within the insert slot 120, and forming an adjustable platform 131 positioned within the insert slot 120 for supporting the watercraft engine 144, the adjustable platform having an adjustable height. The method may further comprise rotatably securing the insert 122 from a lower position aligned with the lower hull 116 of the watercraft to an upper position accommodating water flowing through the insert slot 120 below the insert and out the stern 114 of the watercraft above the bottom surface 116.

Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions is not limited other specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.

Claims

1. A watercraft hull having a constant flow tunnel, the watercraft comprising a bow, stern, lower hull, upper surface, the watercraft hull comprising:

an opening in the body of the watercraft defining a platform slot aligned with the watercraft longitudinal axis from a first end to a second end adjacent the stern, and extending transverse to the watercraft longitudinal axis from the lower hull to the upper surface;

a constant flow tunnel disposed within the lower hull having a first side, a second side, a first end and a second end adjacent the first end of the platform slot, the length of the tunnel between the first and second end being substantially equal to the length of the lower hull along the watercraft longitudinal axis; and the depth of the tunnel at the second end being substantially less than the length of the tunnel.

2. The constant flow tunnel according to claim 1, wherein the ratio of the depth of the tunnel to the length of the tunnel is sufficiently small to permit the watercraft to remain buoyant in relatively shallow water.

3. The constant flow tunnel according to claim 2, wherein the watercraft remains buoyant at a depth of less than one foot of water.

4. The constant flow tunnel according to claim 2, wherein the watercraft remains buoyant at a depth of less than six inches of water.

5. The constant flow tunnel according to claim 1, wherein the ratio of the tunnel depth to length varies between 0.01 and 0.1.

6. The constant flow tunnel according to claim 1, wherein the ratio of the tunnel depth to length varies between 0.01 and 0.05.

7. The constant flow tunnel according to claim 1, wherein tunnel features negligible diversion from the first end to the second end.

8. The constant flow tunnel according to claim 1 further comprising a directional keel extending along the first and second sides of the tunnel and outwardly from the lower hull for providing directional control to the watercraft.

9. The constant flow tunnel according to claim 1, wherein the slope of the tunnel from the first end to the second end approaches the constant rising slope of water upon exiting from beneath the hull and beyond the stern.

10. The constant flow tunnel according to claim 9, wherein the constant rising slope of water upon exiting from beneath the hull and beyond the stern varies between 1-2 inches per foot.

11. A constant flow tunnel propulsion system in a watercraft hull, the watercraft comprising a bow, stern, lower hull, upper surface, and an engine having a propeller for propelling the watercraft, the constant flow tunnel propulsion system comprising:

an opening in the body of the watercraft defining a platform slot aligned with the watercraft longitudinal axis from a first end to a second end adjacent the stern, and extending transverse to the watercraft longitudinal axis from the lower hull to the upper surface;

a tunnel disposed within the lower hull having a first side, a second side, a first end and a second end adjacent the first end of the platform slot; the length of the tunnel between the first and second end substantially equal to the length of the lower hull along the watercraft longitudinal axis; the depth of the tunnel at the second end substantially less than the length of the tunnel; and

an adjustable platform positioned within the platform slot for supporting the watercraft engine, the adjustable platform having an adjustable height.

12. The constant flow tunnel propulsion system according to claim 11, wherein the ratio of the depth of the tunnel to the length of the tunnel being sufficiently small to permit the watercraft to remain buoyant in relatively shallow water.

13. The constant flow tunnel propulsion system according to claim 12, wherein the watercraft remains buoyant at a depth of less than one foot of water.

14. The constant flow tunnel propulsion system according to claim 12, wherein the watercraft remains buoyant at a depth of less than six inches of water.

15. The constant flow tunnel propulsion system according to claim 11, wherein the ratio of the tunnel depth to length varies between 0.01 and 0.1.

16. The constant flow tunnel propulsion system according to claim 11, wherein the ratio of the tunnel depth to length varies between 0.01 and 0.05.

17. The constant flow tunnel propulsion system according to claim 11 further comprising a directional keel extending along the first and second sides of the tunnel and outwardly from the lower hull for providing directional control to the watercraft.

18. The constant flow tunnel propulsion system according to claim 17 wherein the directional keel extends along the first and second sides of the tunnel from the first end to within a buffer distance of the second end, the buffer distance substantially less than the length of the tunnel.

19. The constant flow tunnel propulsion system according to claim 10, wherein the slope of the tunnel from the first end to the second end approaches the constant rising slope of water upon exiting from beneath the hull and beyond the stern.

20. The constant flow tunnel propulsion system according to claim 19, wherein the constant rising slope of water upon exiting from beneath the hull and beyond the stern varies between 1-2 inches per foot.

21. The constant flow tunnel propulsion system according to claim 10, wherein the engine propeller and adjustable platform height are commonly adjusted.

22. The constant flow tunnel propulsion system according to claim 21, wherein the engine propeller is adjusted such that the tunnel deflects water into the propeller and away from the mid-section of the engine.

23. The constant flow tunnel propulsion system according to claim 21, wherein the engine propeller and adjustable platform height may be commonly adjusted by one of an electronic and hydraulic means.

24. The constant flow tunnel propulsion system according to claim 21, wherein the adjustable platform comprises a plate aligned with the engine main axis platform slot.

25. A method for making a constant flow tunnel propulsion system in a watercraft hull, the watercraft comprising a bow, stern, lower hull, upper surface, and an engine having a propeller for propelling the watercraft, the method comprising:

forming an opening in the body of the watercraft defining a platform slot aligned with the watercraft longitudinal axis from a first end to a second end adjacent the stern, and extending transverse to the watercraft longitudinal axis from the lower hull to the upper surface;

forming a tunnel disposed within the lower hull having a first side, a second side, a first end and a second end adjacent the first end of the platform slot; the length of the tunnel between the first and second end substantially equal to the length of the lower hull along the watercraft longitudinal axis; the depth of the tunnel at the second end substantially less than the length of the tunnel; and

forming an adjustable platform positioned within the platform slot for supporting the watercraft engine, the adjustable platform having an adjustable height.

26. The method according to claim 25, wherein the ratio of the depth of the tunnel to the length of the tunnel being sufficiently small to permit the watercraft to remain buoyant in relatively shallow water.

27. The method according to claim 26, wherein the watercraft remains buoyant at a depth of less than four inches of water.

28. The method according to claim 25, wherein the ratio of the tunnel depth to length varies between C and D.

29. The method according to claim 25, further comprising the step of forming a directional keel extending along the first and second sides of the tunnel and outwardly from the lower hull for providing directional control to the watercraft.

30. The method according to claim 25, wherein the engine propeller and adjustable platform height are commonly adjusted.