Ships – Hull or hull adjunct employing fluid dynamic forces to...
Reexamination Certificate
2000-01-19
2001-02-13
Avila, Stephen (Department: 3617)
Ships
Hull or hull adjunct employing fluid dynamic forces to...
Reexamination Certificate
active
06186086
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a hull for a boat having a centrally located V-shaped keel portion beginning at the bow of the boat and flaring into a flat pad, the keel having strake and chine pairs disposed on either side of the keel portion. A first strake is disposed at an outboard edge of a deadrise adjacent the keel portion. A first chine joins the first strake to a second dead rise. A second strake is disposed at an outboard edge of the second deadrise. A second chine joins the second strake to a third dead rise and a third strake is disposed at an outboard edge of the third deadrise. At least one of the chines is a flat chine, one is a reverse chine and one is also a combination chine which further comprises a flat pad superimposed upon a reverse chine. As used hereinafter, a strake or a strake pair which is commonly used to denote a line of planing in a wooden ship's side denotes a planar surface running lengthwise along the hull bottom providing lift or acting as the planing surface. The chine is the juncture of the side of the hull with the bottom in a V-shaped hull, however, the term “chine” also refers to any juncture between hull portions where a hull portion makes a sharp turn upward at the edge of the strake toward the side of the boat. Herein, a chine refers to a chine pair disposed on both sides of the centerline of hull. The deadrise is the angle that the bottom of the boat makes with an imaginary horizontal line representing the waterline. The dead rise may be a constant angle but usually varies along a given surface from the stem to the stern. A standard V-shaped hull design has one deadrise sloping away from the keel and one chine at the juncture of the deadrise with the side of the boat hull.
2. Prior Art Statement
Small boats, particularly those pleasure craft twelve feet or less in length, are subject to certain additional regulations not required of larger craft. One, in particular, states that the craft must negotiate a one hundred eighty degree turn at fill throttle without backing off the throttle. Negotiating such a turn may cause a craft to side-slip through the water, porpoise fore and aft and/or chine walk by yawing right to left while also rolling from side to side. Any of these reactions may also result in discharge of one or more occupants in the craft. Thus, the design of the hull of a boat is critical in alleviating adverse handling characteristics and achieving ride comfort while complying with all boating regulations including the high speed turn. Though the high speed turn requirement does not exist in craft longer than twelve feet L.O.A, (overall length), turning control of these larger craft has been attempted.
For instance, it is known to provide a design for a larger craft boat hull having chine portions joining an upper hull portion to a lower hull portion wherein the chine portions have a substantially horizontal portion extending outwardly from the edges of the lower hull and a chine lip portion extending downwardly at a reverse direction from 12 to 18 degrees from the horizontal. For instance, see the U.S. Pat. No. 4,193,370 issued on Mar. 18, 1980 to Harry L. Schoell.
Additionally, it is known to provide a V-shaped hull design with improved turning characteristics for a larger boat wherein the hull has a plurality of chine pairs comprising downwardly directed wedges extending fore and aft on opposite sides of a centerline keel portion wherein the keel portion comprises a forward V-section merging with a concave planing pad via an upwardly and rearwardly directed transition area. For instance, see the U.S. Pat. No. 4,233,920 issued on Nov. 18, 1980, to Wood, et al.
It is also known to provide a hull design with improved turning characteristics for deep V-hull larger craft wherein the hull design has a planar central running surface extending fore and aft and a concave outboard running surface extending fore and aft wherein the central running surface is separated from the outboard running surface by downwardly directed wedge shaped chines. For instance, see the U.S. Pat. No. 4,361,102, issued Nov. 30, 1982 on to Wood, et al.
It is known to provide a hull design with improved turning characteristics for a deep V-shaped boat hull wherein the hull has two reflex or reverse chine pairs separated by a second deadrise having an angle greater than a first deadrise between the keel and the first reflex chine pair. For instance, see U.S. Pat. No. 4,813,365 issued Mar. 21, 1989 to Lindstrom, et al.
Finally, it is known to provide a water jet saucer having a low beam to length ratio wherein the jet saucer has a substantially rounded bottom and is devoid of lift strakes, deadrises or chine pairs. For instance, see the U.S. Pat. No. 5,375,551 issued on Dec. 27, 1994 to Lunter, et al.
SUMMARY OF THE INVENTION
As hereinbefore recited, the design of the hull of a boat operated in high speed turns can exhibit significant side-slip where the boat urns but slides along in its generally original path as well, or it can exhibit or aggressive biting into the water surface as the severity of the turn increases depending on how the hull is configured. Significant side-slip typically occurs with boats having either substantially flat bottoms or V-hulls with no means, such as chines, to prevent the side-slip. The prior art has addressed the side slippage of these boats by providing downwardly directed wedge shaped chine pairs on either side of the central keel portion as described in the aforementioned V-shaped hull patents. Boats constructed according to these patents however, are very aggressive in turns producing significant biting into the water and the attendant centripetal side forces causing the operator to experience high g-forces in a tight turn at full-out speed, that is at full throttle. The saucer type boat of U.S. Pat. No. 5,375,551 has the opposite handling in turns wherein the saucer side-slips wildly as it has no chines to dig into the surface of the water. High g-forces are still created though by the high output jet pump driving the boat as these high g-forces occur at the moment when the nozzle direction on the pump is abruptly changed causing the saucer to spin about its vertical axis while continuing to move generally along the original course. Pleasure boaters are not accustomed to, or always prepared for these high g-forces and some boaters have been discharged from a pleasure boat in certain high speed turns. Furthermore, pleasure boaters often want to experience a smooth, stable, predictable ride in straight line boating as well as on turns without high g-forces. Additionally, when towing a skier, the pleasure derived from the high speed skiing is lost. Therefore, when using a boat according to the prior art patents, pleasure boaters are forced to significantly reduce speed in turns to prevent the discomfort of the aggressive maneuvering characteristics or the wild sliding of the saucer craft.
The boats of the prior art V-shaped hull patents are primarily intended for high speed fishing boats driven by an outboard engine mounted on a transom of the boat or by an inboard/outboard gear housing mounted at the base of the transom, where the transom is substantially at the rearmost extension of the boat. These boats may have either a propeller or a jet discharge for propulsion but the prop or discharge is disposed well below the waterline at the bottom of the driving unit. V-shaped hull boats driven by inboard mounted jet pumps have different handling characteristics as the steerage of the boat is directed by moving a nozzle of the discharge port from side to side without the rudder like extension of an outboard or inboard/outboard propeller housing. In an inboard mounted jet pump, the nozzle may be substantially at the rearmost portion of the boat but typically is spaced inboard therefrom along the centerline in a discharge tunnel at the keel line of the boat. Thus, the nozzle exits above the waterline creating the propulsion force substantially at and along the keel centerline at
Mauldin Charles C.
Zender James F.
Avila Stephen
Marsh Richard L.
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