VESSEL HULL FOR FORMING WAVEFORMS FOR ATTRACTION OF AQUATIC ANIMALS

Abstract

A vessel for operation on a water surface, having a hull that creates a waveform that attracts aquatic animals such as dolphins when traveling at a speed of 9 to 13 knots. The hull comprises a bow, a rounded stern and a midship section extending from the bow to the stern. The hull has a ratio of a waterline beam to a radius of the stern in a range between 2.0-2.5, and a speed-to-length ratio in a range between 1.5-1.7 to create a soft, curling wake in which dolphins can surf and jump. The hull further has a length-to-beam ratio between 2.5 to 3.0, a flat bottom aft, a high deadrise at the bow, and a full midsection with a longitudinal center of gravity located 52% to 56% aft of a beginning of a waterline to result in a low prismatic coefficient of the hull.

Description

FIELD OF THE INVENTION

The invention relates generally to attracting aquatic animals, and more particularly, to a power boat with a hull designed to create waveforms that attract aquatic animals, and a method for operating such a power boat for attracting aquatic animals using long period waves.

BACKGROUND OF THE INVENTION

Globally, the exploitation of marine mammals, such as dolphins, has shifted from hunting to viewing over the last few decades. Across the diverse spheres of wildlife tourism, whale and dolphin watching has grown more rapidly and globally in popularity than most, and since the first decade of the 21st century, most coastal cetacean populations have been exposed to some form of dolphin-watching.

Marine boat operators have attempted to reproduce underwater sounds in order to attract aquatic animals by means of lures that produce a sound or vibration. A number of rattling or vibrating lures have been produced that attempt to attract aquatic animals by electrically or mechanically generating and transmitting signals that simulate acoustics produced by baitfish. However, aquatic animals generally appear to produce acoustic signals that vary in signal frequency, periodicity, and amplitude. Such complex signals are not readily reproduced by simple buzzers or other devices that generate signals of fixed frequency, duration, and amplitude or that are varied in an arbitrary manner.

Further attempts have been made that involve using a frequency synthesizer to generate signals of varying frequency and broadcasting them underwater in order to influence the behavior of aquatic animals. In addition, underwater acoustical signals produced by actual species of aquatic animals have been recorded. For example, members of a particular species of baitfish may be isolated in a tank or other isolated environment, and signals produced underwater have been recorded by means of an underwater acoustical transducer. A hydrophone has also been used to record the sounds of one or more bass fish actually striking and consuming baitfish, such as a minnow or shad, and reproducing the recorded sounds underwater at a location where it is desired to attract bass.

However, currently existing sound emitting devices used by dolphin watching tour operators are complex, difficult to operate, unreliable and may further fail to emit certain types of sound for the attraction of aquatic animals. The current systems may also lack certain features that limit their usefulness to boat tour operators. Therefore, a need exists for a tour boat and a method for attracting aquatic animals, such as dolphins, toward the tour boat.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a hull of a vessel for operation on a water surface. The hull comprises a bow, a rounded stern, and a midship section extending from the bow to the stern. The hull has a ratio of a waterline beam to a radius of the stern in a range between 2.0-2.5 and a Froude number in a range between 0.44-0.50 or a speed-to-length ratio in a range between 1.5-1.7.

According to a second aspect of the present invention, there is provided a vessel for operation on a water surface. The vessel includes a hull having a shape that creates a big wave when planning at a speed between 9 to 13 knots, preferably 10-11 knots. The hull has a displacement-to-length ratio between 215-250 and a Froude number in a range between 0.44-0.50.

According to a third aspect of the invention, there is provided a method of creating a big waveform that attracts aquatic animals. The method comprises the steps of providing a vessel having the hull, traveling the vessel on a water surface at a speed between 9 to 13 knots, and creating a large waveform. The hull comprises a bow, a rounded stern and a midship section extending from the bow to the stern, and has a ratio of a waterline beam to a radius of the stern in a range between 2.0-2.5, and a Froude number in a range between 0.44-0.50.

Other aspects of the invention, including apparatus, devices, systems, converters, processes, and the like that constitute part of the invention, will become more apparent upon reading the following detailed description of the exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated in and constitute a part of the specification. The drawings, together with the general description given above and the detailed description of the exemplary embodiments and methods given below, serve to explain the principles of the invention. These same numbers are used throughout the figures to reference like figures and components. In such drawings:

FIG. 1 is a front perspective view of a power boat having a hull according to an exemplary embodiment of the invention;

FIG. 2 is a side view of the power boat of FIG. 1;

FIG. 3 is a top view of the power boat of FIG. 1;

FIG. 4 is a side view of the hull of the power boat of FIG. 1;

FIG. 5 is a bottom view of the hull of the power boat of FIG. 1;

FIG. 6 is sectional view of the hull of the power boat according to the exemplary embodiment of the invention along a hull section 10;

FIG. 7 is sectional view of the hull of the power boat according to the exemplary embodiment of the invention along a hull section 6;

FIG. 8 is sectional view of the hull of the power boat according to the exemplary embodiment of the invention along a hull section 0;

FIG. 9 is a front view of the power boat of FIG. 1; and

FIG. 10 is a rear view of the power boat of FIG. 1.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S) AND EMBODIED METHOD(S) OF THE INVENTION

References will now be made in detail to exemplary embodiments and methods of the invention as illustrated in the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the drawings. It should be noted, however, that the invention in its broader aspects is not limited to the specific details, representative devices and methods, and illustrative examples shown and described in connection with the exemplary embodiments and methods.

This description of exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “horizontal”, “vertical”, “front”, “rear”, “upper”, “lower”, “top”, “bottom”, “right” and “left” as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion and to the orientation relative to a vehicle body. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. Additionally, the word “a” as used in the claims means “at least one”.

In the present description, certain terms have been used for brevity, clearness and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatus and methods described herein may be used alone or in combination with other systems and methods.

FIG. 1 shows a marine power tour boat (or ship, or vessel), such as an excursion boat, generally depicted with the reference numeral 10, according to the invention. The power boat 10 is designed for dolphin watching. The power boat 10 is a displacement type of boat having a hull 12 according to an exemplary embodiment of the invention. The hull 12 of the power boat 10 comprises a bow 14, a rounded stern 16, and a midship section 20 extending from the bow 14 to the stern 16. The hull 12 has a design waterline (DWL), a centerline (or longitudinal centerline) (CL), and a longitudinal center of gravity (LCG) (as shown in FIG. 4). The term “centerline” conventionally refers to an imaginary line down the center of a vessel lengthwise. Any structure or anything mounted or carried on a vessel that straddles this line and is equidistant from either side of the vessel is said to be “on the centerline”. The stern 16 is symmetrically shaped around the centerline (CL) as shown in FIG. 5. A keel 22 is arranged on a bottom surface of the midship section 20 providing an outlet position on the hull 12 of the vessel 10 for a propeller shaft 24 as shown in FIG. 2. As used herein, the term “longitudinal” (or “longitudinally”) conventionally refers to a direction from the bow 14 to the stern 16 along the centerline (CL).

As shown in FIGS. 2 and 3, station lines 0-11 show transverse cross-sections at the various stations along a length of the hull 12, where the right half sections depict stations along the bow 14 (ahead of the midship section 20), and the left half sections depict stations along the stern 16 (aft of the midship section 20). The stations 0-11 are disposed between the stations B (bow) and S (stern), which mark longitudinally end (or extreme) points of the hull 12, as shown in FIGS. 2-5. The station 0 marks the beginning of the DWL.

As used herein, the term “bow” conventionally refers to a front portion of the boat 10, from a front-end point (station B), where the hull 12 starts, and the term “stern” conventionally refers to a rear portion of the boat 10, from a rear end point (station S), where the hull 12 terminates. The bow 14 is forward from a station 3 of the hull 12, while the stern 16 is rearward from a station 10 of the hull 12, as illustrated in FIGS. 2 and 3. The term “midship” refers to approximately a middle of the boat's hull 12 as measured from the bow 14 to the stern 16 of the hull 12. Moreover, the longitudinal centerline (CL) is an imaginary line running from the bow 14 to the stern 16 along the middle of the boat 10 down a center of the boat 10 lengthwise.

As shown in FIG. 2, the length overall (L_OA) is the distance between the extreme points forward and aft, i.e., between the stations B and S, measured parallel to the DWL. As used herein, the term “design waterline” (or DWL) conventionally refers to a waterline on a ship when it is floating freely at rest in still water in its normally loaded condition. A waterline length (LWL) is a length of the hull 12 as measured along the design waterline (DWL) when the boat is static. An optimum waterline length according to the exemplary embodiment of the invention is in a range between 40′ to 55′, preferably 46′. However, it is to be understood that the invention is not limited to such a size boat, and expressly includes boats of varying lengths and widths. The description that follows relating to a boat of a particular size is for illustrative purposes only.

A ship's hull form determines many of its main attributes, stability characteristics and resistance, and therefore the power needed for a given speed, seaworthiness, maneuverability, and load-carrying capacity. The hull 12 according to the invention is designed to create waveforms that attract aquatic animals (mammals), such as dolphins, toward the tour boat 10.

The rounded stern 16 of the hull 12 according to the exemplary embodiment of the invention has a stern radius (or radius of the stern 16) R_S (as shown in FIGS. 3 and 5) such that a ratio of a waterline beam (B_WL) (as shown in FIGS. 5) to the stern radius R_S (i.e., waterline beam to stern radius: B_WL/R_S) is between 2.0 and 2.5. As used herein, the waterline beam (B_WL) is a width of the hull 12 at the design waterline (DWL). Preferably, according to the exemplary embodiment, the waterline beam is 16.5′ and the stern radius R_S is 7.5′, thus the waterline beam to stern radius ratio (B_WL/R_S) is 2.2. As used herein, the waterline beam (B_WL) is a width of the hull 12 at the design waterline (DWL). The rounded stern 16 with the waterline beam to stern radius ratio between 2.0 and 2.5 creates a soft, curling wake that attracts dolphins and in which the dolphins can surf and jump.

Moreover, the hull 12 has a deadrise variable along the centerline (CL). The term “deadrise” of the vessel is known in the art as an angle between a horizontal plane and a hull surface 13 (as shown in FIGS. 5-8). In other words, the hull 12 has a flat bottom aft and a high deadrise at the bow 14. Specifically, a stern deadrise D_S of less than 2° (i.e., 2° or less) (best shown in FIG. 6), a midship deadrise D_M between 8° to 16° (preferably 12°) (best shown in FIG. 7), and a bow deadrise D_B between 70° to 80° (preferably 74°) (best shown in FIG. 8).

The hull 12 has a chine flat 18 formed down sides 26 of the hull 12 and around the stern 16 between chines 19, as best shown in FIG. 4-7. In other words, the chine flat 18 extends along both starboard and port sides of the hull 12. The term “chine” in boat design conventionally refers to a sharp change in angle in the cross section of a hull, or a line formed where the sides of a boat meet the bottom. The chine flat 18 has a width of 3% to 4% (preferably 3.5%) of the waterline beam (B_WL) to further increase the wave making ability of the boat 10. As illustrated in FIGS. 4 and 6, the chine flat 18 around the stern 16 is a reverse chine flat having a reverse chine angle G_R of 8-10° (preferably 9°) down the sides 26 on a front portion of the stern 16 (as shown in FIG. 6) and a stern hook angle G_RH of 4-8° (preferably 6°) across the stern 16 approximately between the stations 11 and S (as shown in FIG. 4). The front portion of the stern 16 is defined approximately between the stations 10 and 11 of the hull 12. The reverse chine flat angle G_RH of 4-8° (preferably 6°) across the stern 16 creates a stern hook on a rear portion of the stern 16 defined approximately between the stations 11 and S of the hull 12. Those skilled in the art know that a chine in boat design is a sharp change in angle in the cross section of a hull, while a reverse chine is a chine or spray rail set at a downward angle to deflect spray down and away from the boat. The reverse chine allows for lower planing speeds, as the reverse chines stops the boat pointing its nose skyward and thus transitions to a planing motion at a lower speed.

As seen in FIG. 4, a longitudinal center of gravity (LCG) and a longitudinal center of buoyancy (LCB) are located 52% to 56% (preferably 54%) of the waterline DWL aft of the station 0, which results in a low prismatic coefficient (C_P) of the hull 12. As used herein, the term “prismatic coefficient” (C_P=V_HLWL×Ax) conventionally refers to a ratio of an immersed volume of the hull (V_H) to a volume of a prism with equal length to the waterline length LWL of the ship and a cross-sectional area Ax equal to the largest underwater section of the hull (midship section 20). The prismatic coefficient (C_P) is used to evaluate (or indicate) the longitudinal distribution of the volume of the underbody (i.e., the underwater volume of the hull of the boat). A low or fine C_P indicates a full mid-section and fine ends, a high or full C_P indicates a boat with fuller ends. Planing hulls and other highspeed hulls tend towards a higher C_P. Efficient displacement hulls travelling at a low Froude number will tend to have a low C_P. The prismatic coefficient (C_P) according to the exemplary embodiment of the invention is between 0.48 to 0.54, preferably 0.51. A low prismatic coefficient (C_P) results in a change in direction of waterflow that will slow the water down, which will increase pressure and raise the water in the form of a large wave.

Furthermore, the hull 12 according to the exemplary embodiment of the invention has a block coefficient (C_b) between 0.35 to 0.40 (preferably 0.37), and a midship coefficient (C_m) between 0.68 to 0.74 (preferably 0.71). As used herein, the term “block coefficient” conventionally refers to a ratio of a volume of a displacement of a ship to that of a rectangular block having the same length, breadth, and draft (i.e., the distance from a bottom of the boat to the waterline (DWL)). The C_b gives a sense of how much of the block defined by the LWL, the waterline beam (B_WL) and the draft (T) is filled by the hull. Full forms such as oil tankers will have a high C_b where fine shapes such as sailboats will have a low C_b. As further used herein, the term “midship coefficient” conventionally refers to a cross-sectional area (A_x) of the slice at the midship section (or at the largest section for C_x) divided by the waterline beam (B_WL)×draft (T). It displays the ratio of the largest underwater section of the hull to a rectangle of the same overall width and depth as the underwater section of the hull. This defines the fullness of the underbody. A low C_m indicates a cut-away mid-section, and a high C_m indicates a boxy section shape. Sailboats have a cut-away mid-section with low C_x whereas cargo vessels have a boxy section with high C_x to help increase the C_b.

The hull 12 according to the exemplary embodiment of the invention has a coefficient of waterplane (or waterplane coefficient) (C_w) between 0.74 to 0.78 (preferably 0.76). The C_w is a waterplane area of a ship divided by LWL×B_WL (i.e., the length and breadth of the ship at the waterline). The waterplane coefficient expresses the fullness of the waterplane, or the ratio of the waterplane area to a rectangle of the same length and width. A low C_w figure indicates fine ends and a high C_w figure indicates fuller ends. High C_w improves stability as well as handling behavior in rough conditions. The term “waterplane” conventionally refers to a horizontal plane that passes through a ship on a level with the waterline thereof. Further according to the exemplary embodiment of the invention, a length-to-beam ratio of the waterplane (i.e., LWL/B_WL) is between 2.5 to 3.0 (preferably 2.77).

A displacement-to-length ratio of the boat 10 is between 215 to 250. The displacement of a ship is its weight (conventionally in long tons) based on the amount of water its hull displaces at varying loads. It is measured indirectly using Archimedes' principle by first calculating the volume of water displaced by the ship then converting that value into weight displaced. The length is the waterline length LWL.

Furthermore, a speed-to-length (or speed/length) ratio is preferably in a range between 1.5-1.7, more preferably 1.6. The speed/length ratio is defined as V/√LWL. It is a speed of a ship in knots divided by the square root of the waterline length (LWL) in feet. For example, a boat with the LWL equal to 25′ gives a square root of 5. Therefore, when the boat is moving at 5 knots, the speed/length ratio is exactly 1. At a speed of 10 knots, the speed/length ratio would be 2.

Naval architects also use a dimensionless form of velocity called the “Froude number” (Fn). The speed/length ratio is similar to the Froude number except that the gravity term is omitted. The Fn is defined as F_n=V/29 g×LWL,

where: V=velocity (ft/s);

g=gravitational acceleration (or gravitational constant) (ft/s²); and

LWL=waterline length of ship (or boat) (ft).

According to the exemplary embodiment of the invention, the Fn is in a range between 0.44-0.50, preferably 0.46.

Further according to the exemplary embodiment of the invention, it is determined that dolphins are more likely to interact with a waveform for longer periods of time if the boat 10 making the wave is traveling at 9 to 13 knots, preferably 10-11 knots. The boat 10 operating at the speed-to-length ratio of 1.6 or an Fn of 0.45-0.5 will result in the largest waveform. Using those two variables, a waterline length of 46′ may be chosen.

In operation, the boat 10 having the hull 12 is operated to travel on a water surface at a speed between 9 to 13 knots, preferably 10-11 knots. As a result, the hull 12 of the boat 10 creates a large waveform that attracts aquatic animals (or marine mammals), such as dolphins.

The foregoing description of the exemplary embodiments of the invention has been presented for the purpose of illustration in accordance with the provisions of the Patent Statutes. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments disclosed hereinabove were chosen in order to best illustrate the principles of the invention and its practical application to thereby enable those of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated, as long as the principles described herein are followed. Thus, changes can be made in the above-described invention without departing from the intent and scope thereof. It is also intended that the scope of the invention be defined by the claims appended thereto.

Claims

1. A hull of a vessel for operation on a water surface, the hull comprising: a bow;a rounded stern; anda midship section extending from the bow to the stern;wherein the hull has a ratio of a waterline beam to a radius of the stern in a range between 2.0-2.5 and a Froude number in a range between 0.44-0.50.

2. The hull as defined in claim 1, wherein a stern deadrise angle is less than 2°.

3. The hull as defined in claim 2, wherein a midship deadrise is in a range between 8° to 16°.

4. The hull as defined in claim 3, wherein a bow deadrise angle is in a range between 70°-75°.

5. The hull as defined in claim 1, further comprising a chine flat extending along both starboard and port sides of the hull, wherein the chine flat has a width in a range between 3% to 4% of a waterline beam.

6. The hull as defined in claim 5, wherein the chine flat is a reverse chine flat comprising a reverse chine angle in a range between 8°-10° down sides of the stern on a front portion of the stern.

7. The hull as defined in claim 5, wherein the chine flat is a stern hook comprising a stern hook angle in a range between 4°-8° on a rear portion of the stern.

8. The hull as defined in claim 1, comprising a length-to-beam ratio of a waterplane in a range between 2.5 to 3.0.

9. The hull as defined in claim 1, comprising a block coefficient in a range between 0.35 to 0.40.

10. The hull as defined in claim 1, comprising a midship coefficient in a range between 0.68 to 0.74.

11. The hull as defined in claim 1, comprising a prismatic coefficient in a range between 0.48 to 0.54.

12. The hull as defined in claim 1, comprising a coefficient of waterplane in a range between 0.74 to 0.78.

13. The hull as defined in claim 1, comprising an optimum waterline length in a range between 40′ to 55′.

14. The hull as defined in claim 1, comprising a displacement-to-length ratio in a range between 215 to 250.

15. The hull as defined in claim 1, comprising a longitudinal center of gravity and a longitudinal center of buoyancy located 52% to 56% aft of a station 0 marking a beginning of a waterline.

16. A vessel for operation on a water surface, the vessel including a hull comprising a shape that creates a big wave when planning at a speed between 9 to 13 knots; wherein the hull comprises a displacement-to-length ratio between 215-250 and a Froude number in a range between 0.44-0.50 or a speed-to-length ratio in a range between 1.5-1.7.

17. The vessel as defined in claim 16, wherein the hull further comprises a rounded stern, wherein the hull has a waterline length in a range between 40′ to 55′ and a ratio of a waterline beam to a radius of the stern in a range between 2.0-2.5.

18. The vessel as defined in claim 17, further comprising a chine flat extending along both starboard and port sides of the hull, wherein the chine flat has a width in a range between 3% to 4% of a waterline beam.

19. The vessel as defined in claim 18, wherein the chine flat around the stern is a reverse chine flat comprising a reverse chine angle in a range between 8°-10° on a front portion of the stern and a stern hook angle in a range between 4°-8° on a rear portion of the stern.

20. The vessel as defined in claim 16, wherein the hull further comprises a flat bottom aft, a high deadrise at the bow, a midship section with a longitudinal center of gravity located 52% to 56% aft of a station 0 marking a beginning of a waterline to result in a low prismatic coefficient of the hull.

21. A method of creating a big waveform that attracts aquatic animals, the method comprising the steps of: providing a vessel comprising the hull as defined in claim 1;traveling the vessel on a water surface at a speed between 9 to 13 knots; andcreating a large waveform.

22. The method as defined in claim 21, wherein the aquatic animals are dolphins.