Patent Application
20090188419
This invention relates to high performance boat hull structures. In particular, it pertains to an improved hull structure which improves upon the handling characteristics of a V-bottom hull by combining its characteristics with those of a flat bottom planing hull and with the speed and acceleration characteristics of a tunnel hull boat with improved air distribution across the center hull surfaces and enhanced air flow into tunnel hull configurations outboard of the center V-hull zones for optimal performance.
Tunnel hull boats are designed to trap air underneath the boat hull as the boat moves through water, thereby compressing the air and lifting the boat above the water line defined by the boat's natural buoyancy. The effect of lifting the boat decreases the boat's resistance through the water and allows for faster acceleration and greater boat speeds.
Conventional tunnel hull designs have inherently sacrificed handling characteristics for higher speed performance. In particular, the same hull design that has allowed for lifting the hull out of the water has inhibited banking of the boat when turned, and contributes to porpoising (up and down oscillation of the bow) while turning. Moreover, performance of conventional tunnel hull boats is load sensitive and sea state dependent. That is to say, heavy loads detract from the air capturing and speed enhancing ability of tunnel hull boats, and, as compared to the more traditional V-bottom hull boat, tunnel hull boats are less stable in choppy water.
A high performance boat that combined the speed and acceleration advantages of the tunnel hull with the handling characteristics and stability of the traditional V-bottom hull with decreased resistance to travel through water and certain of the ride characteristics of a sled or flat bottomed hull would be a decided advantage. Decreasing the v-hull resistance to travel through the water would enhance efficiency and decreases fuel consumption. Enhancing the air flow in the tunnels would assist in providing lift, as well as possibly generating bubbles in the tunnel.
The improved boat hull in accordance with the present invention incorporating progressive lift, multiple tunnel, multiple reverse deadrise hydrochines, and spray knocker attributes in a modified V-hull wherein the positioning and configuration of the multiple hydrosponsons successfully combines the high performance capabilities of the tunnel hull with the handling and stability characteristics of the traditional V-bottom hull. The hull in accordance with the present invention includes a V-shaped center hull portion having air distribution features to generate bubbles over the surface of the V-hull, and a pair of outer hydrosponsons that depend downwardly from the gunwales to an outer low-speed running surface. Running surfaces on the bottom of each mid-hull sponson and the pair of outer hydrosponsons may be positioned at about a horizontal attitude up to about 10 degrees as desired to modify the ride, a harsher ride being obtained at near horizontal disposition of the running surfaces with a softer ride obtained with a higher angulation of the surfaces. The hydrosponsons together with the adjacent hull define a tunnel into which air is injected, using an air induction system open at the bow of the boat to provide augmented air into the tunnel. The above described positioning of the sponson base lines allows for banking of the boat when turned, yet provides an enhanced air infection into the tunnel for tunnel hull performance. The sponsons' narrow width and the angulation of the running surfaces provides required stability and ride characteristics without unduly increasing the wetted surface area of the overall hull. Chines extending along part of the length of the V-hull gathers and aids in distribution of air to the bubble forming features positioned on the V-hull surfaces.
The hull designed according to the teachings of this invention exhibits increased structural strength, especially due to the continuous extent of the sponsons along most of the length of the boat hull, a wider than conventional hull providing better stability with lowered power requirements to obtain the same speed and performance. Lower speeds provide planing of the hull and a softer ride is achieved due to the multiple tunnel structure with running surfaces designed to provide optimum lift. The wider hull with hydrosponsons along a large portion of the hull less draft for shallow water operation, while having a higher weight capacity as compared to conventional hull designs. At higher speeds the hull of this invention performs with greater stability, exhibiting a flatter, more stable turning ability with higher speeds attainable in turns. The air bubbles created over the V-hull portion of the bottom enhance the operational characteristics by decreasing resistance to travel through the water, thereby increasing efficiency, increasing operational speeds and decreasing fuel consumption. Finally, the hull described herein rides higher in or on the water exhibiting less turbulence and develops less wake than conventional boat hulls.
Referring to the drawings, an improved hull 10 in accordance with the present invention broadly includes center V-hull portion 12, and a pair of opposed, generally parallel outer sponsons 14, 16 positioned to either side of the V-hull portion 12. Positioned adjacent running surfaces 17, 19, the sponsons 14, 16 extend rearwardly from sponson points 23 and 25 aft of the bow 22 and terminate at stem 28.
Referring to the rear elevational drawing shown in
Positioned on the V-hull surfaces 12 are a pair of strakes 160 and 161 extending along part of the length of the hull with the forward ends 162 and 163 thereof positioned so that air is trapped along the keelward side thereof when moving through the water. Bubble generating discontinuities 164 are located along the V-hull surface 12 and are angled toward the keel so that air is drawn from adjacent strakes 160 and 161 onto the V-hull surface where the air is formed into foam or bubbles to cover most of the surface of V-hull 12 as the boat moves through the water. In one example of an aluminum boat, panels of aluminum are formed and welded to the V-hull surface 12 in a shingled or lapped configuration, with the stepped elements formed by the overlapping sheets forming the bubble forming discontinuities. By having the bubble forming discontinuities angled as shown in the drawings, the drawing of the air from adjacent the strakes 160 and 161 is enhanced.
The angular configuration of the bubble forming discontinuities with respect to the keel may be varied somewhat to accommodate different load and ride characteristics. The angle a may vary from perpendicular to the keel to 80°, the preferred range of 20°-75° to the most preferred range of 30-60°. One example of the bubble forming structure has the discontinuity positioned at 45° and operated successfully.
Forming bubbles on the V-hull portion of a boat hull decreases the resistance to progress through the water and thereby improves speed and efficiency.
In compliance with the statute, the invention has been described in language more or less specific as to structural features. It is to be understood, however, that the invention is not limited to the specific features shown, since the means and construction herein disclosed comprises a preferred form of putting the invention into practice. The invention is, therefore, claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims, appropriately interpreted in accordance with the doctrine of equivalents.
