RECREATIONAL WATER PROJECTILE AND USES THEREOF

Abstract

There are provided safer hand launched swimming pool projectile toys. One projectile comprising an elongate body having a hemispherical nose and a paraboloid tail portion extending from the hemispherical nose to a flat end, and multiple tail fins extending away from the elongate body and positioned proximate the flat end. The other projectile having the overall body shape and tail fins of the V2 rocket, but having an opening across the length and slits down each side to provide safety due to springiness when it impacts the teeth or face of a person.

Claims

1. A projectile for throwing underwater by hand, the projectile comprising: an elongate body having a hemispherical nose and a paraboloid tail portion extending from the hemispherical nose to a flat end; and multiple tail fins extending away from the elongate body and positioned proximate the flat end.

2. The projectile of claim 1, wherein each of the multiple tail fins extend 20 percent or less than a length of the elongate body, and each of the multiple tail fins is positioned at least 0.5 cm from the flat end.

3. The projectile of claim 2, wherein an outer surface of the paraboloid tail portion tapers from the hemispherical nose.

4. The projectile of claim 3, wherein the outer surface of the paraboloid tail portion tapers generally according to the equation: $Y=5.7X^2+0X-3.2$ wherein Y is a length from a vertex of a parabola defining the paraboloid tail portion, and X is a distance from a midline of the parabola.

5. The projectile of claim 3, wherein the elongate body has a hardness of 69 durometer or less.

6. The projectile of claim 5, wherein the hemispherical nose comprises a channel extending therethrough, orientated perpendicular to a longitudinal axis of the elongate body, the channel creating a bumper between a tip of the hemispherical nose and the channel.

7. The projectile of claim 6, wherein, the channel is positioned 4 millimeters behind the tip of the hemispherical nose, and the channel is about 4 millimeters in height and 15 millimeters long.

8. The projectile of claim 3, wherein the elongate body is hollow and comprises a first section, and a second section releasably securable to the first section, the first section forming at least 15 percent of the elongate body, the first section and the second section collectively forming an interior space within the elongate body when releasably secured together.

9. The projectile of claim 8, wherein the first section comprises a threaded portion and the second section comprises a corresponding threaded portion, wherein when the threaded portions of the first section and the second section are operatively coupled together, the second section is releasably secured to the first section to form the elongate body with the interior space therein.

10. The projectile of claim 8, wherein the first section forms about half of the elongate body and includes the hemispherical nose, and the second section includes the tail fins and the flat end.

11. The projectile of claim 8, wherein the first and second sections are loosely coupled together, such that they break apart upon impact.

12. The projectile of claim 3, wherein the elongate body further comprises: an interior space, and a hole positioned at or proximate the flat end in fluid communication with the interior space.

13. The projectile of claim 12, wherein the hole is positioned in the flat end.

14. The projectile of claim 12, wherein the hole has a diameter from 8 to 16 mm.

15. A method of filling the projectile according to claim 12 with water, the method comprising: holding the projectile under the water with the flat end of the projectile facing a top surface of the water; and shaking the projectile vertically under the water.

16. A projectile for throwing underwater by hand, the projectile comprising: a longitudinal axis; a nose; a tail; a body; and a plurality of fins, wherein: the nose has a peripheral portion and a central portion; the peripheral portion has a bridge and a pair of legs that extend from the bridge to the body to form an arch; the legs have interior surfaces that present towards one another and opposed exterior convex surfaces; the central portion is straddled in spaced relation by the peripheral portion and has opposed major surfaces, an edge wall that extends between the opposed major surfaces and has a pair of side surfaces coupled by a transition portion, the major surfaces of the central portion presenting towards the legs; the body extends from the nose to the tail and has an annular surface; the surface of the body, the side surfaces of the central portion and the convex surfaces of the legs are coincident with a notional fusiform contour that extends from the bridge to the tail and that tapers more steeply adjacent the tail; and the fins are radially spaced about and bridge the body and the tail.

17. The projectile of claim 16, wherein: the bridge has a hemispherical surface that presents away from the body; the opposed major surfaces are convex, each generally having the shape of a half round top headstone; the legs have concave interior surfaces; the convex surfaces of the central portion present towards the concave surfaces of the legs; the transition portion of the edge wall is toroidal; and the tail is generally frustoconical and terminates in a planar surface.

18. The projectile of claim 17 wherein each fin terminates short of the tail, has a leading edge that extends outwardly from the axis and towards the nose at an acute angle to the axis and a trailing edge disposed at an angle to the axis.

19. The projectile of claim 17, wherein the plurality of fins comprises a pair of fins spaced apart in the direction of the legs and a pair of fins spaced apart in the width of the central portion.

20. The projectile of claim 19, having a length of about 25 cm, a mass of about 290 grams, a material hardness of less than about 69 durometers.

21. The projectile of claim 20, having about the following dimensions expressed as a percentage of overall length: TABLE-US-00006 Body Length 53 Maximum diameter 20 Diameter at tail junction 9 Diameter at nose junction 17 Tail Length 13.6 Minimum diameter 2.6 Peripheral Portion Length 33 Leg thickness 1.6 Central portion Maximum thickness 11.5 Length 25.1 Fin Length 26.7 Thickness 1.6 Offset from tail end 2.6

22. The projectile of claim 21, made of solid rubber.

23. The projectile of claim 21. wherein. if the projectile. thrown underwater, hits a person. the peripheral portion absorbs the impact sufficiently to avoid mouth or facial injury.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments of this invention will now be described by way of example only in association with the accompanying drawings in which:

[0017] FIG. 1A is a side view of a recreational water projectile according to a first embodiment.

[0018] FIG. 1B is a cross-sectional view along line A-A of FIG. 1A.

[0019] FIG. 1C is a cross-sectional view along line B-B of FIG. 1A.

[0020] FIG. 2 is a side view of a recreational water projectile according to a second embodiment.

[0021] FIG. 3 is a rear perspective view of the recreational water projectile of FIG. 2.

[0022] FIG. 4 is a cross-sectional view along line C-C of FIG. 2.

[0023] FIG. 5 is a side view of a recreational water projectile according to a third embodiment.

[0024] FIG. 6 is an exploded perspective view of the recreational water projectile of FIG. 5.

[0025] FIGS. 7A to 7D are top views of various examples of 3-dimensional plastic-shell printed prototypes of recreational water projectiles.

[0026] FIG. 8 illustrates an example recreational water projectile with a modified ideal form overlaid over an example recreational water projectile with an ideal form.

[0027] FIG. 9 illustrates an example of a dodge-the-torpedo game being played using any one of the recreational water projectiles of FIGS. 1 to 6.

[0028] FIG. 10 illustrates a multiplayer version of the dodge-the-torpedo game of FIG. 9.

[0029] FIG. 11 illustrates a method of throwing the recreational water projectile of FIG. 7B in a manner that causes the recreational water projectile to leap up over the water.

[0030] FIG. 12 is a perspective view of a projectile according to another example embodiment;

[0031] FIG. 13 is a top view of the projectile of FIG. 12;

[0032] FIG. 14 is a side view of the projectile of FIG. 12;

[0033] FIG. 15 is a front view of the projectile of FIG. 12;

[0034] FIG. 16 is a rear view of the projectile of FIG. 12;

[0035] FIG. 17 is a view similar to FIG. 13;

[0036] FIG. 17A is a view along 17A-17A of FIG. 17;

[0037] FIG. 17B is a view along 17B-17B of FIG. 17;

[0038] FIG. 17C is a view along 17C-17C of FIG. 17;

[0039] FIG. 17D is a view along 17D-17D of FIG. 17;

[0040] FIG. 18 is a view similar to FIG. 14;

[0041] FIG. 18A is a view along 18A-18A of FIG. 18;

[0042] FIG. 18B is a view along 18B-18B of FIG. 18

[0043] FIG. 18C is a view along 18C-18C of FIG. 18;

[0044] FIG. 19 is a view similar to FIG. 13

[0045] FIG. 19A is a view along 19A-19A of FIG. 19

[0046] FIG. 19B is a view along 19B-19B of FIG. 19

[0047] FIG. 19C is a view along 19C-19C of FIG. 19

[0048] FIG. 20 is a perspective view of a projectile according to another example embodiment;

[0049] FIG. 21 is a side view of the projectile of FIG. 20;

[0050] FIG. 22 is a top view of the projectile of FIG. 20;

[0051] FIG. 23 is a front view of the projectile of FIG. 20;

[0052] FIG. 24 is a front view of the projectile of FIG. 20;

[0053] FIG. 25 is a view similar to FIG. 21;

[0054] FIG. 25A is a view along 25A-25A of FIG. 25;

[0055] FIG. 25B is a view along 25B-25B of FIG. 25;

[0056] FIG. 25C is a view along 25C-25C of FIG. 25;

[0057] FIG. 25D is a view along 25D-25D of FIG. 25;

[0058] FIG. 26 is a view similar to FIG. 22;

[0059] FIG. 26A is a view along 26A-26A of FIG. 26;

[0060] FIG. 26B is a view along 26B-26B of FIG. 26;

[0061] FIG. 26C is a view along 26C-26C of FIG. 26;

[0062] FIG. 27 is a view similar to FIG. 21;

[0063] FIG. 27A is a view along 27A-27 of FIG. 27;

[0064] FIG. 27B is a view along 27B-27B of FIG. 27; and

[0065] FIG. 27C is a view along 27C-27C of FIG. 27.

[0066] The novel features which are believed to be characteristic of the present invention, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following discussion and a review of the attached drawings in which presently preferred embodiments of the invention will now be illustrated by way of example only.

[0067] It is expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. Also, unless otherwise specifically noted, all of the features described herein may be combined with any of the above aspects, in any combination. In the drawings, like reference numerals depict like elements.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0068] One aspect of the present disclosure is a recreational water projectile or torpedo that is safe to throw underwater by hand, even when it is thrown with the intent of actually hitting another person. The projectile can be thrown underwater by hand as part of games and/or sport and can move quickly enough to make the game/sport a challenge, and can be controlled for throwing during a competitive play.

[0069] The recreational water projectile 10 generally includes an elongate body 12 and multiple tail fins 14 extending away from the elongate body 12.

[0070] In known toy torpedoes, features for the projectile were optimized hydronamically, which included features such as a pointy nose and pointed tail. However, hard, pointed nosed tend to be dangerous if the object is thrown in a forceful manner and hits another player, particularly in in the face, mouth, or the eye. It was discovered that a projectile with a hemispherical nose and paraboloid body shape offered the best compromise between safety and speed of the projectile for a dodge-the-torpedo type of game. Thus, as best seen in FIGS. 1 to 6, the elongate body 12 has a hemispherical nose 16 with a tip 15 and a paraboloid tail portion 18 that extends from the hemispherical nose 16 to a flat end 20. In some applications, the hemispherical nose 16 may have a diameter from 3.5 to 5.5 cm, and preferably a diameter of about 4.5 cm.

[0071] The paraboloid tail portion 18 may be paraboloid in that an outer surface of the paraboloid tail portion 18 tapers or narrows as it extends from the hemispherical nose 16. In some applications, the outer surface of the paraboloid tail portion 18 tapers generally according to the equation:

[00002]$Y=5.7X^2+0X-3.2$

where Y is a length from a vertex of a parabola defining the paraboloid tail portion, and X is a distance from a midline of the parabola.

[0072] The drag coefficient on a spherical nose structure is generally understood to be six times greater than the drag coefficient on a more pointy, ellipsoidal nose (page 41 of Joubert document) (Joubert 2004). To compensate for the drag of the hemispherical nose, the tail portion was designed to be fully paraboloid, and asymptotic to the hemisphere at the nose. This paraboloid body shape helps to compensate for the initial resistance at the nose by lowering water pressure and flow along the rear section of the torpedo. In effect, this adjusts the flow of water along the body length to helping push the device forward.

[0073] Based on direct measurements of material hardness, as set out in Table 1, existing toy torpedoes manufactured using solid rubber or solid plastic all have a hardness of at least 70 durometer. Indeed, the material hardness has actually trended higher over the years. The newest available toy torpedoes include that produced by the Underwater Torpedo League (UTL) that copies the V2-rocket-shape of the Original Toypedo of Warner 1996, as well as the identically shaped Torpedo STRIKE that are intended for team sport similar to underwater rugby. The UTL torpedo and the Torpedo Strike products are all about 87 durometer in hardness, which is the same hardness as an ice-hockey puck. The official torpedo of the Underwater Torpedo League and the Torpedo Strike product are both exact physical copies of the shape of the discontinued original Toypedo, which measured 79 durometer in hardness. The rationale for using such a hard material for the UTL torpedo league may be to suit that rugby-like sport, in which players battle underwater to rip the torpedo out of each others' hands. Even all of the versions of the Toypedo by Swimways has/had a hardness of 79 to 88 durometers (see Table 1).

[0074] For the present application, the recreational water projectile 10 is intended to be thrown with the intent of actually hitting another person. Thus, the recreational water projectile 10 may have a hardness of 70 durometer or less, preferably a hardness of 65 durometer or less, and more preferably a hardness of 60 durometer.

[0075] To identify the preferred hardness of the recreational water projectile 10, prototype toy torpedoes with hardness values of 49, 55, 60, 65, and 70 durometer were made of rubber and tested (see Table 1). The feel in the hand during game play, and the performance through the water were found to be the same for all hardness values tested. However, the most striking difference between the different rubber-hardness prototypes was observed by bumping the nose of the prototype torpedoes onto a person's forehead by hand. The 49-durometer toy torpedo was tolerable when hitting or tapping it on a person's forehead, and the 49-durometer torpedo was very unlikely to cause a bump on the forehead from underwater play. However, the 70-durometer toy torpedoes were found to be very painful when hitting or tapping on the forehead, and those could certainly cause a bump on the head or break a tooth during underwater play. It was found that toy torpedoes manufactured of solid rubber or solid plastic material with a hardness reading that is less than 60 durometer perform as well as those made of harder materials.

[0076] Further, the recreational water projectile 10 may be solid (see FIGS. 1A to 1C, for example) or hollow (sec FIGS. 3 to 6, for example).

[0077] In applications where the recreational water projectile 10 is solid, a further safety feature is shown in FIGS. 1A to 1C. The depicted recreational water projectile 10 comprises a channel 17 positioned proximate the tip 15 in the hemispherical nose 16 that extends from one side of the recreational water projectile 10 to the other. The channel 17 is shown to extend generally perpendicular relative to the longitudinal axis of the recreational water projectile 10, and is oval-shaped in cross-section. In alternate applications, the channel 17 may be a different shape, such as rectangular in cross-section. The channel 17 may be located 2 to 5 millimeters behind the tip 15 of the hemispherical nose 16, whereby the dimensions of the channel 17 may have a height of about 3 to 5 millimeters and a length of about 10 to 20 millimeters through the hemispherical nose 16. In a preferred embodiment, the channel 17 may be located 4 millimeters behind the tip 15 of the hemispherical nose 16, and the dimensions of the channel 17 may have a height of about 4 millimeters and a length of about 15 millimeters. In other applications, the channel 17 may be positioned at a different distance from the tip 15 and may have different dimensions.

[0078] The channel 17 positioned in the hemispherical nose 16 creates a type of bumper 19 at the tip 15 end of the recreational water projectile 10. With harder materials, a bumper may not be of much use, because the harder material will not flex much. But in application where the recreational water projectile 10 is made from 65-or-lower durometer rubber, the introduction of the channel 17 just behind the tip 15 allows the bumper 19 of the hemispherical nose 16 to compress (such as by a few millimeters) if/when the recreational water projectile 10 hits a person or object underwater. The presence of the flexible bumper 19 helps prevent injury to the tooth, eye, or face when the recreational water projectile 10 is thrown at someone.

[0079] Hollow, water-filled toy torpedoes are known, for example, the Toypedo Hydro by Swimways, is filled with water through an inflation nozzle that seals the water cavity like air in an inflated ball. Another water-filled toy torpedo is the Sharkpedo (), which has openings at the bow and the stern (nose and tail) to let air escape so water fills the device easily. However, those underwater projectiles that are filled with water are heavy, and they weigh more than one kilogram. They are far too cumbersome for use in a one-on-one goal-scoring game, and can cause injury if thrown at another player. The current underwater projectiles that have openings at the front and back may be easy to fill and empty with water. However, they are inefficient for the present purposes, because the sudden throwing force tends to push water out of the hole at the back of the object. The acceleration from throwing the object, like the Sharkpedo, drains water out through the tail end, wasting much of the kinetic energy of momentum that would normally push a solid device forward through the water.

[0080] Thus, FIGS. 2 to 4 illustrate an embodiment of the recreational water projectile 10 with a hollow interior space 22, and with a single aperture or hole 24 positioned within the diameter of the flat end 20 in fluid communication with the interior space 22. In an alternative embodiment, the hole 24 may be positioned between the tail fins 14. Further, the hole may have a diameter from 8 to 16 mm. In the depicted embodiment, the diameter of the hole is about 10 mm.

[0081] FIGS. 5 and 6 illustrate another embodiment of the recreational water projectile 10 with a first section 26 and a second section 28 that is releasably securable to the first section 26. When releasably secured together, the first section 26 and the second section 28 collectively form the interior space 22 within the elongate body 12. In the depicted embodiment, for the sections to be releasably securable together, the first section 26 comprises a threaded portion 30, and the second section 28 comprises a corresponding threaded portion 32. When the threaded portion 30 and the corresponding threaded portion 32 of the first section 26 and the second section 28 are operatively coupled together, the second section 28 is releasably secured to the first section 26 to form the elongate body 12 with the interior space 22 therein. In other applications, the first and second sections 26, 28 may have different coupling structures to releasably secure the first and second sections 26, 28 together. For example, the first and second sections 26, 28 may each have corresponding snap-fit features or may be dimensioned to frictionally engage together. In other applications, the first and second sections 26, 28 may be releasably coupled together with magnets. In cases when the first and second sections 26, 28 have snap-fit features, magnets, or frictionally engage together, the coupling may be configured (or loosely coupled) such that the first and second sections 26, 28 break apart when the recreational water projectile 10 hits another object with sufficient force.

[0082] In the depicted embodiment, a scam 34 between the sections 26, 28 is positioned laterally, approximately halfway, along the elongate body 12. In this manner, the first section 26 forms approximately half of the elongate body 12 and includes the hemispherical nose 16, while the second section 26 forms approximately the other half of the elongate body 12 and includes the flat end 20. In other applications, the first section 26 may form 15 percent or more of the elongate body 12, with the second section 28 forming the remaining portion of the elongate body 12. In that regard, the seam 34 may be positioned laterally at a different place along the elongate body 12, for example, where the hemispherical nose 16 meets the paraboloid tail portion 18. In alternative applications, the seam 34 may be positioned longitudinally along the elongate body 12, or may be positioned at a non-perpendicular or non-parallel angle relative to the longitudinal axis of the elongate body 12.

[0083] With this embodiment, the recreational water projectile 10 may be filled with water by holding the first and second sections 26, 28 under the water and twisting the threaded portion 30 and the corresponding threaded portion 32 together. The recreational water projectile 10 may correspondingly be emptied of water by unscrewing the first and second sections 26, 28 apart.

[0084] In some applications, the first and second sections 26, 28 may be made of the same material with the same or similar hardness level. In other applications, the first and second sections 26, 28 may be made of different materials that may have different hardness levels. For example, for further safety purposes, the first section 26 may be made of a material with a lower hardness level (i.e. is softer) than the second section 28.

[0085] Some of the advantages of the recreational water projectile 10 are that the plastic parts can be manufactured inexpensively, they are light when empty, and are exceptionally easy to fill and empty with water (as will be described further below).

[0086] The embodiments of the recreational water projectile 10 shown in FIGS. 1 to 6 each further have four tail fins 14 that extend away from the elongate body 12 and are positioned proximate the flat end 20. Notably, each of the multiple tail fins extend 20 percent or less than a length of the elongate body 12, and each of the multiple tail fins 14 is positioned at least 0.5 cm from the flat end 20. In the depicted embodiment, the tail fins 14 are positioned straight, or in parallel, with the longitudinal axis of the recreational water projectile 10. In other applications, the recreational water projectile 10 may have a different number of tail fins 14, and the tail fins 14 may be positioned in a spiral formation around the elongate body 12. In yet further other applications, the tail fins 14 may be positioned from 0.25 cm to 0.75 cm from the flat end 20. The flat end 20 may have a circumference of 1 to 2 cm, or preferably about 1.4 cm.

[0087] The recreational water projectile 10 of the present disclosure may range in length from about 10 to 40 cm, and more preferably, between 18 cm and 26 cm, with a length to width ratio of about 4 and 6, and more preferably, between 4.5 and 5.5. They preferably have a mass of between about 50 and 500 grams, and more preferably, between 250 and 350 grams.

Experiments

[0088] To assess the ability of the recreational water projectile 10 to travel through water via manual propulsion, three-dimensional, hollow plastic printings were made. FIGS. 7A-7D show four torpedoes of differing shapes produced for testing. The body of the embodiment of FIG. 7A has an ellipsoid shape, while the body of the embodiments in FIG. 7B, 7C, and 7D have the hemisphere-paraboloid shape. The four torpedoes produced were 25 cm long, hollow, hard-shell plastic, three-dimensional prototypes manufactured by 3D printing.

[0089] The ellipsoid shape of FIG. 7A is also referred to herein as a modified ideal form. A toy torpedo having the ideal form is described in Warner (U.S. Pat. No. 5,514,023) (Warner 1996), and this form was manufactured as a toy torpedo by Swimways Corporation USA, referred to as the original Toypedo. This ideal form was modified to achieve the present modified ideal form by incorporating a planar truncation at the tail end. This planar truncation at the tail end provided a flat surface to place a finger behind the tail fins. Notably, the tip of the nose of the ideal form torpedo was also flattening out. FIG. 8 shows the outline of the prototype described above as modified ideal form, overlaid onto an example toy torpedo with the ideal form for a submarine or torpedo (Joubert 2004). The dimensions of the prototype shown in FIG. 7A is set out below in Table 2.

TABLE-US-00001 TABLE 2 Dimensions of the body of the prototype toy torpedo having the modified ideal form. CENTIMETER CENTIMETER FROM TAIL DIAMETER 0.0 1.47 0.5 1.64 4.6 2.99 7.6 3.74 10.4 4.35 12.7 4.49 16.1 4.40 17.2 4.37 18.5 4.12 19.3 3.97 20.8 3.45 22.1 2.99 23.0 2.30 23.6 1.09 23.7 0.00

[0090] The embodiments depicted in FIGS. 7B-D each have a hemispherical nose with a diameter of 4.4 cm at their widest, and the equation for the silhouette of the shaft parabolas is Y=5.7X.sup.2+0X3.2, where Y is the cm length from the vertex of the parabola, and X is the cm distance from the midline of the parabola. The flat end of the toy torpedo is the plane across 3.2 centimeters above the vertex, and the asymptotic sphere at the nose end is located at Y=23 centimeters from the tail. The embodiment shown in FIG. 7B has five short spiral fins, the embodiment shown in FIG. 7C has four short straight fins, and the embodiment shown in FIG. 7D has four long straight fins.

[0091] The prototypes of FIGS. 7A to 7D were tested along with the original Toypedo having the ideal form, and a solid rubber prototype have the modified ideal form as described above.

[0092] At first, the hollow shell prototypes were tested for underwater performance by injecting them with a semi-solid jell, through a 10 mm hole drilled into the tail. Performance of the gel-filled modified ideal form prototype was suitable, but eventually, the gel broke down, since the three-dimensional printed shell was porous and storage of the device in the water dissolved the gel. Subsequently, it was discovered that performance of the water-filled prototype remained acceptable.

[0093] Generally, it was expected that the less-streamlined, hemisphere-paraboloid design would be less efficient than the more streamlined ellipsoid toy torpedoes. Another expectation was that that the passive travel distance with the hemisphere structure, when thrown by hand underwater, would not be as far as the distance of the modified ideal form described above, or of the original Toypedo, with its shape that matches the ideal form according to Joubert (Joubert 2004) and of Warner (Warner 1996).

[0094] Testing was done by throwing the modified ideal form, the hemisphere-parabola versions, the original Toypedo, of similar size and mass of about 290 grams (but which has the ideal form), and other existing toy torpedoes in a swimming pool with a constant water depth of four feet. See Tables 3 and 4. The toy torpedoes were thrown by hand using about 75% maximal throwing force, releasing them from the hand within one foot (30 cm) of the water surface. Harder throws using 100% effort was found to cause the torpedoes to veer wildly off course. Manual testing was used because the purpose of the experiment was to study torpedo performance using the hands of a person, as that is the method of actual and intended use for the recreational water projectile 10.

[0095] The distance travelled was measured from the wall of the swimming pool, which was the point where the thrower's back foot was planted, to the point where the torpedo settled on the bottom. One throw of each torpedo was done in random order, and the distance recorded. The process was repeated, and the results, the mean distances travelled, and the variability of those distances are presented in Table 3.

TABLE-US-00002 TABLE 3 Distance travelled under the water by hand-thrown toy torpedoes Mean Standard Type of prototype or toy torpedo tested Number of distance deviation of (Image number. Description.) tests (feet)* distance (feet) 1. Ideal form, original Toypedo pool torpedo 22 19.66 2.63 2. Modified ideal form solid rubber 13 20.35 0.69 3. Modified ideal form 3D printed shell 20 20.73 1.46 4. Hemisphere five short spiral fins 3D printed shell 21 20.43 1.61 5. Hemisphere four short straight fins 3D printed shell 18 19.78 1.56 6. Hemisphere four long, straight fins 3D printed shell 19 19.42 1.97 Combined Total 113 20.05 1.84 *Analysis of variance (ANOVA) comparisons of mean distance traveled, among the six types of toy torpedo: Degrees of Freedom: between 5 groups, within 112, F = 1.54, p = 0.184 (indicating no significant differences among mean values). **Levine test assesses whether there are any significant differences in the reproducibility (variance) of distance traveled among the devices. There were substantial differences in reproducibility, p = 0.001. Difference in variance from Toypedo (Labeled as 1. above) versus modified-ideal form in solid rubber (2.), p = 0.0001; Toypedo versus prototype number 3.. p = 0.0125; Toypedo versus prototype 4. p = 0.0322; Toypedo versus prototype 5. p = 0.0328; Toypedo versus long-fin prototype 6, p = 0.220 (i.e. 1 versus 6, no difference).

[0096] It was found that there were no statistically significant differences among the projectiles in terms of the mean distance travelled. The fact that no difference in distance was detected is believed to be attributable to the structures and shapes of these toy torpedoes that were all designed to be efficient in the context of their use. However, the original Toypedo, with its ideal body form and large fins, demonstrated the greatest variability in distance travelled. That variability is believed to be attributable to the difficulty in handling and throwing toy torpedoes that have a pointy tail end, and the large, exaggerated tail fins. This conclusion is confirmed by the results with the toy torpedo that had the second worst reproducibility, namely, the 3D-printed, hemisphere-parabola torpedo (FIG. 7D) with its longer tail fins that stretch along 34 percent of the body length (see Table 4, appended). Based on this study, it was found that recreational water projectiles/toy torpedoes for throwing by hand underwater perform better in terms of their ease of handling and better reproducibility of distance thrown (smaller variance or standard deviation) when they have shorter, smaller tail fins, that extend along less than 20 percent of body length.

[0097] Surprisingly, there was no statistical difference in mean of distance travelled among the devices tested. Moreover, the hemisphere-parabola shaped projectiles/torpedo travelled a conventional, straight, downward-curving path (see Table 4).

[0098] In contrast, the prototypes that were of the modified-ideal form exhibited a consistent, and unusual, upward-pitching behavior. The hollow plastic, or a solid rubber, toy torpedo that has a hemispherical nose has a broader area of impact when it hits another person, and therefore, it is implicitly safer than a conventional toy torpedo nose shape that is ellipsoidal or pointed. Importantly, and surprisingly, that additional safety feature does not come with the cost of impaired performance relative to the original Toypedo, whose body shape is of the ideal form. Based on the empirical data of the experiments summarized in Tables 3 and 4, theoretical differences in terms of distance and speed from optimal hydrodynamics were not statistically evident when used in a pool.

[0099] During the study, it was also unexpectedly discovered that the projectiles 10 with the hole 24 could be filled with water in a short period of time by shaking it up and down underwater, with its tail pointing up. Conversely, the hollow recreational water projectiles 10 with the hole 24 could also be emptied easily of water by shaking it above the water with its tail pointing down.

[0100] Thus, the present disclosure provides a method of filling the recreational water projectile 10 with water, the method comprising holding the recreational water projectile 10 under the water with the flat end 20 facing a top surface of the water, and shaking the recreational water projectile 10 vertically under the water. The shaking may be performed for 35 second or less before the recreational water projectile 10 was filled with water. With more vigorous shaking, the recreational water projectile 10 may be filled with water within 30 seconds.

[0101] In a similar manner, the present disclosure also provides a method of emptying the recreational water projectile 10 of water, the method comprising holding the recreational water projectile 10 out of the water with the flat end 20 facing downwards, and shaking the recreational water projectile 10 vertically. The shaking may be performed for 35 second or less before the recreational water projectile 10 was emptied of water. With more vigorous shaking, the recreational water projectile 10 may be emptied of water within 30 seconds. This case and speed of filling and emptying came as a surprise, because it had been expected that the hole 24 was too small to permit rapid passage of water, due to the single opening and water viscosity. It was only after performing the procedure, as described above, that it was realized that the single opening/hole 24 was practical for emptying and filling, with the shaking producing an energetic pumping action to fill and empty the recreational water projectile 10. Moreover, with a single opening/hole 24, the loss of water due to the acceleration from the throw was prevented. The suitability of a hard shell 3-dimensional (3D) printed prototype with the hole 24 (diameter of 10 mm) at its stern came as a surprise, both in terms of the case of filling and emptying, as well as due to its in-water performance. The present hard plastic hollow recreational water projectile 10 has the commercial advantage that it can be manufactured inexpensively by injection moulding, or blow-moulding, and the hollow recreational water projectile 10 is lighter to ship and carry than the solid version.

[0102] FIGS. 9 to 11 illustrate examples of how the recreational water projectile 10 may be used recreationally, such as in a dodge-the-torpedo game. FIG. 9 shows a thrower 100, the person dodging 102, the recreational water projectile 10, the bottom-weighted straps 104 that mark the zone that the person dodging 102 must stay between, the top weight or fastener 106 that holds down the zone-marking straps 104 onto the deck of the swimming pool 108 and the water level 110. The dotted line 112 represents the path of motion that the recreational water projectile 10 went through. This dodge-the-torpedo game may involve the offence player 100 throwing one or more of the recreational water projectiles 10 at another player 102, who tries to evade or dodge being hit or touched by the recreational water projectiles 10. This dodge-the-torpedo game can be played in shallower water that is 3-4 feet deep (90-120 centimeters) so that one can jump or dodge the recreational water projectiles 10 more readily. In some instances, the thrower 100 must be at least 6 feet (two meters) from the player being aimed at 102 (the dodger). As well, during the game, the dodger 102 must remain between the two vertical markers 104 along the wall of the swimming pool 108 that demarcate the zone for game play. Without a suitable zone for play, the game becomes a less interesting chasing game, like tag. Markers 104 along the wall of the swimming pool 108 make this dodge-the-torpedo a practical game of throwing and dodging. The two vertical markers 104 may each be one-inch (2.5 cm)-wide straps. Affixed at the bottom end of each strap 104 may be a weight 114 of at least two ounces (60 grams). The strap 104 must be long enough such that the other end of each strap 104 extends above the water 110 so that it can be clamped in place, or held with a weight 106 on the deck of the pool 108. The markers 104 may long enough to reach at least 3 feet down below the water surface 110. A particularly enjoyable version of the dodge-the-torpedo game may be for the thrower 100 to start by holding three recreational water projectiles 10, and then throwing them, one after the other, at the dodger 102 inside the area defined by the markers 104 along the wall of the pool 108. Three throws in rapid sequence adds fun and action for the person doing the dodging 102.

[0103] For three or more players, FIG. 10 illustrates a multiplayer version of the dodge-the-torpedo game of FIG. 9, showing the two throwers 100, the goggle-wearing person dodging 102, the recreational water projectile 10, and the surface of the water 110. The weighted straps 104 are placed down the side of the pool deck 108 where the straps 104 indicate the position from which the throwers 100 must stay apart, and the zone within which the person or persons dodging 102 must remain during play. In such an application, the dodger 102 remains in a defined area between throwers 100, who are about 12 feet (4 meters) apart. The recreational water projectiles 10 are thrown by players 100 from one side of the area to players 100 at the other side, each trying to hit the dodger or dodgers 102 in the middle.

[0104] FIG. 11 illustrates a method of throwing the modified ideal form of the recreational water projectile 10 (FIG. 7A, for example), by a person 100 standing in the water of a swimming pool, releasing it from the hand 116 just above the water surface 110, at a slightly downward angle onto the water surface 110. The dashed line 112 shows path of motion caused by this method, that makes the recreational water projectile 10 leap up over the water, similar to the leap of a dolphin.

[0105] Various methods may be employed to throw the recreational water projectile 10. One method is to place a finger at the flat end 20 while gripping the elongate body 12 around the fins 14, and throwing it underwater with a follow-through flick of the finger that propels the recreational water projectile 10 into a unique path through the water, whereby it consistently pitches upward toward the surface, before slowing to settle on the bottom.

[0106] Another method of throwing this modified ideal form of the recreational water projectile 10 is by holding it at its tail end, the way one would hold the handle of a pan, and then smacking the recreational water projectile 10 down onto the water surface at a slightly downward angle. This method propels the recreational water projectile 10 initially downward under the water, and then the recreational water projectile 10 pitches up out of the water like a dolphin's leap over the water. The additional speed from smacking the recreational water projectile 10 into the water amplifies the upward pitch of this device, whereby it initially goes downward into the water, and then jumps up from the water like a dolphin, as shown in FIG. 11. This behaviour offers an enjoyable effect when people are simply playing catch with the toy torpedo in the shallow water of swimming pool.

[0107] There are three ways that might cause this upward-pitching behavior: (i) net buoyancy, that is, it floats; (ii) if overall density is greater than that of water, but if the nose is less dense than the tail, then the recreational water projectile 10 points upward as it moves through the water; (iii) appropriately angled tail fins or a curvature in the body of the recreational water projectile 10 act like a rudder to steer the projectile's forward motion upward. But none of those apply here. For a solid object like a rubber torpedo, the curvature-of-projectile's-body approach was described previously (PCT/CA2021/051021). The approach of using fins or body shape to direct the curvature of the path of motion requires the projectile to be positioned correctly around its long axis so that the fins produce a predictable path during the throw. That directional positioning to ensure that the rudder-fin direction is pointing up, down, left or right is very difficult to achieve for a player during a competitive game.

[0108] The surprising and consistent upward motion, or positive pitch, of the spinning, hollow-shell, as well as the identically shaped solid rubber toy torpedo prototypes, reveals a fourth (iv) method of directing the recreational water projectile 10 upward, and that method is a beneficial feature during the two-person goal-scoring game described by Vieth (Vieth 2022) (PCT/CA2021/051021). That upward pitch of the solid rubber toy torpedo prototype happens regardless of its rotational positioning when it is thrown underwater.

[0109] If the torpedo moves fast, as happens when it is splashed down onto the water surface, the upward pitch is so severe that it makes the toy torpedo jump out of the water like a dolphin. That is, even if the throw initially aims the solid rubber toy torpedo prototype downwards at a slight angle of about 10 degrees below horizontal, the projectile will curve and move upward, before eventually slowing and settling to the bottom of the pool.

[0110] To test whether the upward rising, positive pitch is related to the spiral-inducing fins, or whether the positive pitch is because of an artifact of weight or density distribution along the solid rubber torpedo, other torpedoes were manufactured having five fins that were directed in line with the long axis of the torpedo; i.e. fins that were not angled, and did not cause spiralling (see Table 4). The result of underwater testing using the straight-finned projectile design was a conventional, generally descending path of motion to the toy torpedo. Hence, the upward rising, dolphin-like-leap phenomenon of the solid rubber torpedo with its distinctive combination of its five angled tail-fins, its modified ideal form at the nose, and its flat tail, is not an artifact of weight or density distribution, or a rudder-type effect.

[0111] The dolphin-like leap is a useful feature when playing catch underwater or if standing in a shallow pool, because the leap keeps the recreational water projectile 10 closer to the surface, and in play.

[0112] A further embodiment of the projectile is shown in FIGS. 12-19C and indicated by general reference 200.

[0113] This projectile has a body 202, a nose 204 from which the body extends and four fins 206.

[0114] The body defines a longitudinal axis A-A, has a planar tail 208 that is normal to the axis, extends to the tail from the nose and is a parabloid which tapers from nose to tail according to the equation:

[00003]$Y=5.7X2+0X-3.2$

where [0115] Y is a length in (centimeters) from a vertex of a parabola defining the paraboloid tail portion, and [0116] X is a distance (in centimeters) from a midline of the parabola.

[0117] The nose 204 includes a dome portion 210, a bumper portion 212 and a bridge portion 214.

[0118] The dome portion 210 is a portion of a hemisphere having a diameter equal to the maximum diameter of the body 202 and to which the body 202 extends.

[0119] The bumper portion 212 is an arcuate segment of a hemisphere, this hemisphere having a [0120] diameter X wherein [0121] Y is the distance from the tail to the tip of the dome portion

[00004]$Y=5.7X2+0X-3.2$

[0122] The innermost surface of the bumper portion 212 has a planar surface 216 flanked by two concave portions 218, the concave portions 218 being portions of a cylinder having a diameter of approximately 80% of the diameter of the hemisphere and having a common origin therewith, the planar surface 216 being perpendicular to the longitudinal axis A-A of the body and being spaced from the origin a distance equal to about 75% of the radius of the hemisphere.

[0123] The dome portion 210 is coupled to the bumper portion 212 by the bridge portion 214 which, in combination with the concave portions, defines a pair of troughs 222.

[0124] In this embodiment, the troughs terminate in the body and the bridge portion and each trough, in combination with the dome, has a saddle shape 224.

[0125] The fins 206 are radially equally spaced about the body 202. The outermost edge 226 of each fin defines a line that is substantially coincident with the junction of the body 202 and the nose 204. The fins 206 extend approximately 18% of the length of the projectile and terminate about 50.2 mm short of the tail. The leading edge of each fin is disposed at an angle of about 45% to the axis and the trailing edge is disposed at an angle of about 40.5 to the axis. Each fin is about 40 mm thick.

[0126] The projectile has a mass of about 290 grams and has a stiffness of about 69 durometer.

[0127] The length of the projectile, from tip of bumper to flat end of tail, is about 2512.6 mm.

[0128] A yet further example embodiment is shown in FIGS. 20-27C. The projectile 300 has a longitudinal axis L-L, a nose 302, a tail 304, a body 306 and a plurality of fins 308.

[0129] The nose 302 has a peripheral portion 310 and a central portion 312.

[0130] Peripheral portion 310 has a bridge 314 and a pair of legs 316 that extend from the bridge 314 to the body 306 to form an arch. The legs 316 have interior concave surfaces 318 that present towards one another and opposed exterior convex surfaces 320. The bridge 314 has a planar surface 322 that presents towards the body portion 306 and an opposed hemispherical surface 324.

[0131] The central portion 312 is straddled in spaced relation by the peripheral portion 310 and has opposed major convex surfaces 326 that each generally has the shape of a half round top headstone, an edge wall 328 that extends between the opposed convex surfaces 326 and has a pair of side surfaces 330 coupled by a transition portion 332, the convex surfaces 326 of the central portion 312 presenting towards the concave surfaces 318 of the legs 316 and the transition portion 332 of the edge wall 328 being generally toroidal.

[0132] The tail 304 is generally frustoconical and terminates in a planar surface 334.

[0133] The body 306 extends from the nose 302 to the tail 304 and has an annular surface 336.

[0134] The surface 336 of the body 306, the side surfaces 330 of the edge wall 328 and the convex surfaces 320 of the legs 316 are coincident with a notional fusiform contour 338 that extends from the hemispherical surface 324 to the tail termination 334 and that tapers more steeply adjacent the termination of the tail.

[0135] The fins 308 are radially spaced about and bridge the body 306 and tail 304. Each fin 308 terminates short of the tail end 334, has a leading edge 340 that extends outwardly from the axis and towards the tail at an acute angle a to the axis and a trailing edge 342 disposed at angle to the axis.

[0136] The example projectile 300 has the following characteristics:

TABLE-US-00003 Mass 290 grams Overall length L1 25 cm Stiffness 69 durometer Fins 2 spaced apart in the direction of the legs 316 2 spaced apart in the width of the central portion Angle a of leading edge to axis = 45 Trailing edge, re-entrant, angle to axis 85 Dimensions, expressed as a percentage of overall length Body Length L2 53 Maximum diameter D1 20 Diameter at tail junction D2 9 Diameter at nose junction D3 17 Tail Length L3 13.6 Minimum diameter D4 2.6 Peripheral Portion Length L4 33 Leg thickness T1 1.6 Central portion Maximum thickness T2 11.5 Length L5 25.1 Fin Length L6 26.7 Thickness T3 1.6 Offset from end L7 2.6

[0137] Persons of ordinary skill will readily appreciate that the above structure creates a double-nose structure so that the nose collapses slightly, so as to soften the pressure of impact, if the projectile hits an object.

[0138] Whereas specific embodiments of the double-nose structure are herein shown and described, it will be evident that variations in shape, geometry and construction material are possible.

[0139] Thus, it is apparent that there have been provided, in accordance with the present invention, useful modifications to projectiles suitable for sport, and methods for throwing and playing catch underwater. The present invention provides structures and equipment which fully satisfy the goals, objects, and advantages set forth herein-before. Therefore, having described specific embodiments of the present invention, it will be understood that alternatives, modifications and variations thereof may be suggested to those skilled in the art, and that it is intended that the present specification embrace all such alternatives, modifications and variations as fall within the scope of the appended claims.

[0140] Additionally, for clarity and unless otherwise stated, the word comprise and variations of the word such as comprising and comprises, when used in the description and claims of the present specification, is not intended to exclude other additives, components, integers or steps. Further, the invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.

[0141] Moreover, words such as substantially or essentially, when used with an adjective or adverb is intended to enhance the scope of the particular characteristic; e.g., substantially planar is intended to mean planar, nearly planar and/or exhibiting characteristics associated with a planar element.

[0142] Further, use of the terms he, him, or his, is not intended to be specifically directed to persons of the masculine gender, and could easily be read as she, her, or hers, respectively.

[0143] Also, while this discussion has addressed prior art known to the inventor, it is not an admission that all art discussed is citable against the present application.

TABLE-US-00004 TABLE 1 Features of prior art passive-motion toy and experimental torpedoes*, listed in approximately chronological order. Body Hardness** Body Diameter Ratio Density of at Mid Shaft Length maximum Length/ material Mass of Body Product name Description cm cm Diameter g/cm3 g Durometer Knapp, 1945 Real MK45 408.9 56.9 7.2 Metal Not 100 Torpedo (Knapp Torpedo; Hemisphere given and Levy 1945) nose, tubular body. Knapp, Solid metal for 215.9 47.2 4.4 Metal Not 100 Experimental water-tunnel tests. given (Knapp and Hemisphere nose, Peabody 1944) tubular body. Poolaris Solid Rubber 23.3 4.6 5.1 1.52 389 70 Toypedo (original) Ideal form, Solid 24.8 4.8 5.2 1.05 290 79 Plastic body (PVC) Toypedo (middle) Plastic, solid body 17.8 3.24 5.5 1.1 102 78 Toypedo (mini) Plastic, solid body 12.5 2.1 6.0 1.1 37 88 Toypedo 25.sup.th Non-torpedo-like, 24.7 4.9 5.0 1.05 302 81 Anniversary hourglass shape, edition with finned nose and tail Sharkpedo Waterfilled plastic 46.1 9.5 4.9 1.2 671 96 shell, openings at nose and tail. Torpedo toy Hard plastic shell 31.4 4.8 6.5 1.66 601 100 sand-filled cylinder, rounded-cone front Toypedo Hydro Ideal form, hollow 41 8.47 4.8 1.1 1600 n/a vinyl body Underwater Ideal form, Solid 24.8 4.8 5.2 1.25 320 87 Torpedo League Plastic body (PVC) Modified-ideal Solid Rubber prototype 23.7 4.4 5.4 1.15 287 49 form Modified-ideal Solid Rubber prototype 23.7 4.4 5.4 1.15 287 55, 60, form other variations tested 65, 70 *All pre-existing toy torpedoes have elliptical or pointy, non hemispherical noses. Ideal-form is the body shape shown in and in Warner (Warner 1996) and (Joubert 2004) **Material hardness measured in triplicate at the mid-length using a Shore Type A Durometer. Values are means of triplicate readings, calibrated against air (0 durometer) and steel plate (100 durometer).

TABLE-US-00005 TABLE 4 Motion behavior through water of Prototypes and commercially available toy torpedoes. Wing- body Fin Ratio Fin: span of Path of motion Mass # Angle length Length Body Fins when thrown Product name Body Material g of Fins of fins cm cm length cm underwater* Prototype 3D, plastic shell, 295 5 6 25.0 4.3 0.17 4.72 Straight, but Modified water filled by Consistent upward ideal form shaking. curving, positive (FIG. 7A). pitch, motion path, Protype Solid Solid Rubber. 70 290 5 6 23.7 3.9 0.17 4.59 until it slows and Rubber** durometer. descends Modified ideal form Prototype Solid Solid Rubber 50 290 5 6 23.7 4.0 0.17 4.59 Modified durometer. ideal form Prototype 3D plastic shell, 295 5 6 25.0 4.3 0.17 4.72 Straight, but HemiSphere nose water filled by descending, no to Paraboid body, shaking. upward pitch 5 angled, spiraling fins (FIG. 7B) Prototype 3D plastic shell, 295 5 6 25.0 4.3 0.17 4.72 HemiSphere nose water filled by to Paraboid body, shaking. 4 short, straight fins (FIG. 7C) Prototype 3D plastic shell, 295 5 6 25.0 8.6 0.34 4.72 HemiSphere nose water filled by to Paraboid body, shaking. with long, straight fins (FIG. 7D) Poolaris Solid Rubber, 389 5 6 23.0 6.9 0.30 6.26 the original toy torpedo Toypedo (middle) Solid Plastic 102 4 6 17.3 4.4 0.26 4.24 Toypedo (Bandit) Solid Plastic 37 4 0 13.8 4.0 0.29 3.48 Original Toypedo Solid Plastic; 290 4 0 24.7 6.5 0.26 4.75 polyurethane Toypedo Hydro Vinyl, water- 1477 4 0 41.0 10.8 0.26 10.35 inflated via adapter from hose. Sharkpedo*** Hard plastic body, 1465 4 + 3 0 46.1 10.4 0.23 13.3 Vinyl head, holes at nose + tail *Description of path followed when thrown underwater. Near-straight indicates that the path traveled varies, depending on imperfections in the overall shape of the toy torpedo. **Rubber hardness value of 70 durometer is relatively hard; 50 durometer is softer ***The Sharkpedo has 4 fins at the tail, and 3 fins along the body mimicking a shark Wingspan is distance between outer tips of opposite-side fins; i.e. the diameter around outer tips of the fins