Title of Invention: FISHING LURE MIMICKING FISH UNDULATING MOTION

Technical Field

[1] The invention relates to artificial fishing lures. An artificial fishing lure is usually attached to an end of a fishing line and moves relatively to water; the purpose of the lure is to attract fish to bite the lure and to be hooked by means of a hook incorporated in the lure. Various methods to attract fish are used: they may include lure movement relatively to water, lure hydrodynamic performance, lure resemblance to a prey fish, lure color, lure scent and others. More specifically, the invention relates to towed through water artificial fishing lures which attract piscivorous fish by resemblance of the lure to a prey fish where the above-mentioned resemblance achieved by the lure hydrodynamic performance.

A reason for necessity to improve existing fishing lures

[2] The present description discloses a fishing lure where the improvement consists in better resemblance or better mimicking of a swimming prey fish. The question whether better mimicking characteristics of the fishing lure do improve the chances of the lure to be bitten should be discussed. In other words, it may be trivial or obvious for humans to think that better mimicking characteristics do improve the chances of the lure to be bitten but the lure is intended for fishes and therefore answering of this question must be approached as a comparison of piscivorous fish reactions to different fishing lures having different mimicking characteristics. A clue for answering this question may be found in biology. Some species of freshwater mussels use striking strategies in their life cycle. Larvae of different mussel species of genus Lampsilis must undergo a parasitic stage in which the larvae are attached to host fish gills. Gravid females of these species have flapping symmetric external parts of mantle which strongly resemble to a human observer a small swimming fish. More specifically, these external parts of mantle are elongated structures strongly resembling a small fish in three dimensions; they have a 'head' with two 'eyespots', a 'trunk' and a 'tail'; moreover, during flapping these structures produce series of pulses which propagate in undulating manner along the structures. A detailed description including pictures illustrating this phenomenon is provided in L.R.Kraemer, The mantle flap in three species of Lampsilis (Pelecypoda: Unionidae). Malacologia, 10, 225-282 (1970). There was a disagreement for decades in science whether these external mantle structures are lures used by mussels to attract and infest attacking piscivorous fish or whether these structures are used by mussels for some another purposes, for example aerating eggs located between the symmetric mantle parts. The results of laboratory encounters between several species of mussels and fishes reported in W.R.Haag and M.L.Warren JR, Mantle displays of freshwater mussels elicit attacks from fish, Freshwater Biology 42, 35-40, (1999) demonstrated clearly that the flapping external mantle parts of these mussels are in fact elaborated lures eliciting attacks from fish and resulting infestations of the attacking fish gills by larval mussels. The results of phylogeny study of DNA of some mussel species reported in D.T. Zanatta, R.W. Murphy, Evolution of active host- attraction strategies in the freshwater mussel tribe Lampsilini (Bivalvia: Unionidae), Molecular Phylogenetics and Evolution 41, 195-208, (2006) presented as evolutionary trees showed that mussel species having at present active mantle flap lures have mussel ancestors which did not have lures at all. Therefore, there is an evidence that these mussels evolved from stage of mussels which did not have lures to stage of mussels having elaborate lures. It can be supposed that at present these lures are so elaborate because of natural selection and that the present stage of mussels having elaborated lures could not evolve by a sudden leap. Rather, the present stage is a result of slow accumulation of mutations which gave the mussels advantage in reproduction: mussels having by mutation external mantle parts resembling a small fish evoked potential piscivorous host fish to attack them more frequently comparatively to mussels which did not have this feature. The greater attack frequency caused greater infestation rate of the host fish by mussel larvae transmitting therefore genes of resembling small fish lure owners to next generations. During evolution this resemblance transformed into even more elaborate form because of aforementioned advantage in reproduction caused by the resemblance: the mantle parts received three dimension form resembling a small fish, the flapping of the mantle parts became undulation-like, decorative eyespots (L.R. Kraemer & CM. Swanson, Functional morphology of 'eyespots' of mantle flaps of Lampsilis (Bivalvia: Unionacea): Evidence for their role as effectors, and basis for hypothesis regarding pigment distribution in bivalve mantle tissues, Malacologia, 26(1-2), 241-251,(1985)) evolved on the lure 'heads'. It can be summarized that the resemblance of a lure to a prey fish does have a significance in aspect of chances of the lure to be bitten by a piscivorous fish: the more the lure resembles a prey fish (at least to the level of three dimensional similarity and mimicking a prey fish undulating behavior), the better is the lure.

Technical problem

An artificial lure prototype: a real prey fish

[3] Features of a typical fish (for example: perch, Percafluviatilis ) self-propulsive

movement, thereinafter fish locomotion, are well known ( excellent photographs illustrating fish locomotion can be found in J.Gray, Studies in Animal Locomotion. I. The Movement of Fish with Special Reference to the Eel, J.Exp Biol 10, 88-104 (1933)). The fish locomotion comprises side-to-side body oscillations; these oscillations are different in phases and amplitudes, so the adjacent to the head trunk portion oscillates first and the caudal fin oscillates last, the amplitude of the adjacent to the head trunk portion is the smallest and the amplitude of the caudal fin is the largest. When seeing the process as a whole, there is a sinusoidal wave propagating along the trunk (the fish body portion beginning at the rearward end of the head and ending at the forward end of the anal fin), caudal region (the next fish body portion beginning at the forward end of the anal fin an ending at the forward end of the caudal fin) and the caudal fin. The aforementioned locomotion mode is called thereinafter undulation. It can be observed and supposed that during undulation diverse physical phenomena are happening. When the sinusoidal wave is propagating from the adjacent to the head forward end of the trunk to the rearward end of the trunk and after that to the caudal fin, each subsequent oscillating body portion of this wave path adds energy to the undulation system by its own muscular contraction and receives energy from the preceding oscillating body portion. It can be modeled as if a first small trunk portion, represented here as a point and located near forward end of the trunk oscillates and therefore produces a first pulse which travels as a wave from the point of oscillation towards the rearward end of the trunk. A second point located on the first pulse path oscillates in phase with the first oscillation producing a second pulse which travels as a wave towards the rearward end of said trunk. It can be seen that during undulation these two pulses or waves are coherent with zero difference in phase. The coherence of the waves with zero difference in phase means that there will be a constructive interference or summation of energies of these waves. Therefore, at a third point located on the second pulse path, these two pulses will form a single wave carrying combined energy of these two pulses. During undulation, this phenomenon happens among typical fish continuously: each part of the body oscillates harmonically starting at forward end of the trunk and ending at the forward end of the caudal fin, the anterior oscillations add energy to the posterior regions and in phase with the posterior oscillations; the combined energy of the whole body oscillations arrives to the caudal fin. At the caudal fin a second phenomenon takes place: the whole muscular mass energy transmitted to the propagating wave with aforementioned combined oscillation energy arrives to stiff but very light weighted caudal fin with relative big lateral surface area. The energy must be conserved, so what is moved side by side and backward by the light caudal fin is relatively big amount of water whose mass and speed correspond to the energy of the whole fish body oscillations. The water is shed backward and the fish moves by reaction forward. That is the way a thrust forward is produced.

Background Art [4] There are existing fishing lures that include some elements of flag flutter. However, it is unknown in the art of fishing lure design that the exact physical explanation of an undulating behavior of some lures is flag flutter. From the other side, the related scientific knowledge on flag flutter does not suggest utilizing the flag flutter phenomenon in fishing lures design. The art of fishing lure design and the scientific knowledge on flag flutter are different spheres which have not been combined prior to the disclosure of the present invention.

Background art; known technical phenomena which are similar to the technical problem

[5] It was discovered and reported in J. Zhang, S. Childress, A. Libchaber& M. Shelley,

Flexible filaments in a flowing soap film as a model for one-dimensional flags in a two-dimensional wind, Nature, vol. 408, 835-839, (2000) that there is an analogy between fish swimming and flapping of a flag. Said discovery is different from the present invention: the flexible filament constituting a flag which is disclosed in the article is not suggested to be utilized as a fishing lure; said filament is fixed using a thin tube introduced normal to the fluid flow plane whereas the present invention is not fixed to a flagpole and constitutes a self-supporting and a self-balancing unit. Said flexible filament does not have external appearance of a fish and does not have a caudal fin whereas the present invention resembles a real fish and has a caudal fin acting as a propulsion blade.

Background art; related knowledge on flag flutter

[6] A simple explanation of an onset of the complex flag flutter phenomenon is given in

M.Argentina and L. Mahadevan, Fluid-flow-induced flutter of a flag, Proceedings of the National Academy of Sciences of the United States of America, (2005). The authors explain the onset of the flutter by a resonance response 'between the mode of oscillation of a rigid pivoted airfoil in a flow and a hinged- free elastic plate vibrating in its lowest mode'. According to this explanation, a flag has two modes of oscillation frequencies: the first one is the oscillation frequency of a flag as a hinged or pivoted airfoil immersed in the flow (the flag has a fixed leading edge and a free trailing edge; assuming that this structure is unbendable or rigid and pivoted or hinged at the leading edge, it will oscillate in a flow in a pendulum-like mode when seen from above; the frequency of these oscillations proportional to the fluid flow speed). The second mode of oscillation frequency of the flag is that of the elastic bending vibrations of the flag (this time the flag assumed as hinged-free but bendable, the second mode is the natural or the lowest frequency of these elastic bending vibrations; these vibrations remain bending oscillations of a beam when seen from above). At a critical fluid flow speed when the aforementioned first mode of oscillation frequency becomes equal to the second mode, the resonance phenomenon arises and the flag starts to flutter. It can be seen therefore, that the more elastic the flag plate is (in other words, the lower bending stiffness is), the lower the critical fluid flow speed at which the flutter arises will be. For example, said first mode of oscillation frequency of a steel flag and of a cloth flag having the steel flag dimensions and being in the same fluid flow is identical.

However, said second mode of oscillation frequency of these two flags is different: the natural or lowest oscillation frequency of a steel plate is very high relatively to the natural oscillation frequency of a cloth plate with same dimensions. This means that at a reasonable speed of a flag towed through a fluid by a human, the cloth flag will flutter whereas the steel flag will not.

[7] A detailed report of experiments with flag flapping in water is provided in

M.Shelley, N.Vandenberghe and J. Zhang, Heavy flags undergo spontaneous oscillations in flowing water, Physical review letters (2005). The experiments described in this work demonstrate clearly that in order to flap (a term equivalent to the flutter) in water instead of air, the flag inertia (mass per unit length) must be sharply increased.

Prior art: existing fishing lures mimicking fish undulating motion

[8] US Patent No. 857,883 issued on June 25, 1907 to John D. Kreisser, titled 'Artificial minnow fishing bait' describes an 'animated fishing lure' made of separate sections pivotally jointed together. The head of the lure is weighted so the lure is balanced in water. The lure sections are made of thin hollow copper. When trolled or pulled through water, the lure imitates a live minnow. The Kreisser's invention represents rich class of presently used lures comprising 2 or more articulated parts (usually from 2 to 4) which pivotally secured (fixed or hinged) one to another. The lateral view of these lures resembles a real fish silhouette. Each of aforementioned parts may be weighted in the bottom. When pulled through water, the aforementioned parts oscillate in different phases producing wave-like motion. The example of lures similar to the Kreisser's invention are US patent No. 2,685,145 issued on Aug.3, 1954 to H.O. Dean, titled 'Sectional Fish Lure' and US patent No. 6,560,914 issued on May 13, 2003 to C.B. Kruger, titled 'Fishing lure with life-like swimming action'. The Kreisser's lure is different from the present invention: the Kreisser's lure divided into 2 or more parts whereas the present invention is a unit constituting a single whole. This is very significant difference because whereas both types of lures mimic prey fish and prey fish undulation, no real fish is divided into parts. The zigzagging wave propagating along Kreisser's lure when drown in water consist only of the oscillations of the finite number of straight parts whereas the body bending wave produced by a real fish during undulation and the body bending wave which arises during towing of the present invention approach mathematically smooth pattern comprising almost infinite number of points of oscillation (comparatively to 2-4 segments, in fish this number depends on number of vertebrae, for example, vertebral count of European Roach is 39-41). The aforementioned pivotal securing elements are instantly move and therefore must produce some hydro acoustic noise while the lure is being pulled through water. This noise is not natural for piscivorous fish and therefore may frighten off the fish. The present invention avoids these noises because it does not have any pivotal securing elements. When seen from above, the Kreisser's lure can be presented as a fluttering in water chain whereas a real prey fish and the present invention can be presented as fluttering in water rope. This difference can be called here as 'smoothness'. It is clear that a momentum conservation which is essential to a propagating wave is more effective in a smoothly oscillating 'rope' comparative to a zigzagging 'chain'. Also, the difference in 'smoothness' produces the following differences in the hydrodynamic performance which, in turn, affect the attractiveness of the lure to the piscivorous fish: the vortices (the wake) shed to water from the present invention body portion resemble better the vortices shed to water by body of a real prey fish during undulation than the vortices shed by the Kreisser's lure. Finally, producing of the Kreisser's lure is relatively complicated because production of different parts and a connection between these parts are needed whereas producing of the present invention is simple because it constitutes a whole unit and therefore may be produced by a single pouring into a mold.

[9] US Patent No. 1,250,189 issued on December 18, 1917 to George Kinsey, titled

'Angling Clip' describes a fishing clip which acts as a fixing device for a pork rind resembling a minnow. The Kinsey's lure is weighted by a sinker attached to the clip. When drown through water, the Kinsey's lure undulates or waves. The Kinsey's lure is different from the present invention: the present invention mimics undulation of a real fish by a combination of undulation of the body portion of the present invention and by transmission of all undulation energy to flapping of the stiff caudal fin constituting a propulsion blade. Moreover, the size and the stiffness of the caudal fin (which are simply chosen approximately as those of an imitated real fish) insure that all undulation energy of lure body portion arriving to the caudal fin is approximately equal to the energy of water which is shed backwards by the flapping caudal fin (see 'detailed description of the invention'). The utilization of the combination of the undulation and the flapping leads to high visual and hydrodynamic resemblance of the present invention to a real prey fish. The Kinsey's lure does not have a stiff caudal fin;

therefore its visual and hydrodynamic performance will be different from those of the present invention. This type of fishing lures is still produced in recent years; sometimes these lures have a caudal fins made of same material as the lure body. One example of these lures is model 'Meat minnow' of Uncle Josh Bait Company

(http://www.unclejosh.com) made of natural pork fat. These lures are different from the present fishing lure for the same reason as the Kinsey's lure: they do not comprise an attached to the trailing end of the lure body propulsion blade (the caudal fins of these lures which are also made of pork fat only mimic visual appearance but do not mimic technical action of a real fish caudal fin; in order to mimic the technical action, the caudal fin-like propulsion blade, as disclosed in the present description, must be stiff like a real fish caudal fin or like swimming fins etc.).

] US Patent No. 1,264,627 issued on April 30, 1918 to William A.Foss, titled 'Artificial bait' describes a fishing lure comprising a rigid weighted body and a flexible tail strip or pork rind attached to said body. During drawing through water said tail strip or pork rind will wiggle or undulate. The Foss' invention is different from the present one: the undulating portion of the Foss' invention is tail portion and the remaining portion of the lure body is rigid whereas the present invention undulates along all length of the lure body (the body portion of the present invention). Also, the directions of undulation oscillations of the tail portion in Foss' invention lie on plane which is perpendicular to the water surface .The directions of undulation oscillations of a real prey fish and of the present invention lie on plane which is parallel to the water surface. Technical solutions of US patents No. 1,582,171, No. 1,535,957 and No. 1,709,010 are close to those of the Foss' No. 1,264,627 patent and these inventions are different from the present one for the same reasons.

] US Patent No 2,229,239 issued on January 21, 1941 to Lester M. Davis, titled

'Fishing plug' describes a fishing plug comprising a body made of single piece of metal tubular material with fin mounted on the body and a flexible tail located behind the body. As the lure is pulled through water, the body and the fin deflect the flow of water causing the tail to wobble in the life-like manner. The Davis's invention is different from the present one: the wobbling action of Davis's invention is caused by an obstruction located before the tail whereas the present invention utilizes different phenomenon of flag flutter which does not need any obstruction located before the fluttering part. More specifically, the obstruction in Davis invention resembles a nozzle which is also used in French patent FR 2,625,867; the comparison of the nozzle solution and technical solution of the present invention is given below in the French patent paragraph.

] US Patent No. 2,503,672 issued on April 11, 1950 to Frederick W. Johnson et al, titled 'Artificial fish bait or lure' discloses an elongated fishing lure comprising flexible strip which wiggles when it pulled through water. The flexible strip disclosed in the Johnson's invention must be inherently curved. The Johnson's lure is different from the present invention: directions of oscillations of Johnson invention cannot be exactly side-to-side like direction of body oscillations of a real prey fish or of the present invention (the directions of side-to-side oscillations of the real prey fish body and of the present invention lie on one plane which is parallel to water surface). Rather, the direction of oscillations of said strip will be a plurality of directions lying on differently sloped planes (the longitudinal axis of said strip lies on each one of these planes and they are sloped relatively to the plane of water surface). Also, the Johnson's lure does not have a caudal fin which acts as a propulsion blade.

[13] French patent No. FR 1,038,291 titled ' Leurre pour la peche' (Fishing lure) invented by Dubrandy Frederic-Felix-Marie, published on Sep. 28, 1953 describes a fishing lure comprising a hook and a flexible strip resembling a fish silhouette. The strip is weighted in its head portion in its lower side and mounted on a hook (the strip is fixed at its leading end and at a second fixation point located approximately at the rearward end of the head portion). The strip is bent between these two fixation points and this bending creates a bulge. On tow through water part of the strip starting at the second fixation point and ending at the rearward end of the strip assumes a wave-like motion. The Dubrandy's invention is different from the present one: the wave propagating along the Dubrandy's lure is caused by said bulge interacting with water flow whereas the fluttering of the present invention is not caused by a drag wake/disturbance created by an obstruction located before the fluttering part. According to the definition of a flag presented in the present invention description, the leading edge of the flag is only fixed and it need not be located behind any obstruction. Therefore, the waving mechanisms of Dubrandy's invention and of the present one are completely different: the Dubrandy's lure receives energy of water flow only at the bulge part whereas the present invention receives energy of the water flow along all the length of the body, the Dubrandy's lure waving is caused by an obstruction whereas the fluttering of the present invention is caused by flag flutter phenomenon.

[14] US Patent No. 3,070,917 issued on Jan. 1, 1963 to David E.Rowe SR, titled 'Fish Lure' describes a fishing lure formed from an elastomeric polymer and having the design and proportions of a live bait fish. The head of Rowe's lure may be weighted; the lure comprises a thin flexible metal or nylon wire extending longitudinally from the head to the tail through the lowermost portion of the lure body with weights positioned on the wire. The Rowe's invention is different from the present one: when pulled through the water, the Rowe's lure will 'oscillate from an upright position describing a half roll, first one way and then the other' (lines 63-68 in the column 2 in Rowe's patent) whereas the present invention performs an undulating motion. It can be summarized that in Rowe's invention oscillations do not propagate along the lure body and therefore the body of Rowe's invention does not produce an undulating wave as it happens during undulation of a real prey fish or during fluttering of the body portion of the present invention.

[15] French patent No.FR 1,315,834 titled 'Fish bait or lure', invented by Mauroy Jean Charles Desire, published on Jan. 25, 1963 and also published as GB 959,974, discloses a fishing lure having a bulged forward portion weighted at its lower part, a thin intermediate portion which is either flexible or hinged and bulged weighted rear portion. On tow through water, said rear portion oscillates from side to side resembling a movement of a fish tail. The Mauroy's invention is different from the present one: the only oscillating part of the Mauroy's lure is the tail whereas the present invention oscillates along the entire body portion length producing a sinusoidal wave. The

Mauroy's invention acts as a hinged hydrofoil oscillating in the water flow in pendulum-like mode whereas the present invention constitutes a fluttering flag with oscillations which arise along all the flag length and propagate along the flag as a sinusoidal wave.

[16] US Patent No. 3,122,853 issued on March 3, 1964 to John C. Koonz et al, titled

'Fishing lure' describes a 'pork strip' type of lure. The lure comprises plastic strip which must be attached to a hook by threading the hook through aperture located at leading edge of the strip. When the lure is trolled, it will assume wavy motion. The Koonz's fishing lure is different from the present invention: keeping in mind the flag definition presented below in the present description, it can be seen that the leading edge of the flag must be fixed in sense that flag mounting means must not allow the flag to rotate round the longitudinal axis of the flag. It can be seen that Koonz provides no means to keep the plastic strip stationary round the plastic strip longitudinal axis (the plastic strip attached to a hook which is attached to a fishing line, therefore, the hook can rotate almost freely round longitudinal axis of its shank). This means that oscillation directions of Koonz's invention cannot be exactly side-to-side like directions of body oscillations of a real prey fish or of the present invention (as mentioned above, the directions of side-to-side oscillations of the real prey fish body and of the present invention lie on one plane which is parallel to water surface). Rather, the directions of oscillations of said plastic strip will lie on a plurality of planes lying round longitudinal axis of said plastic strip. Therefore, the waving, if it happens in spite of rotation round the longitudinal axis or together with the rotation, will be sporadic and will not resemble the regular fluttering of the present invention. Finally, the Koonz's fishing lure does not resemble a prey fish and does not have a head and a caudal fin, whereas the present invention is characterized by these features.

[17] French patent No. FR 2,625,867 titled 'Poisson leurre pour la peche' (Lure fish for fishing), invented by Robert Avias, published on July 21, 1987 discloses a fishing lure comprising a rigid head and a flexible body. During towing through water, water enters the 'mouth' located on front of the head and emerges behind the head causing the body to vibrate and wave. The Avias's invention is different from the present one: the head portion of the Avias's lure acts as a nozzle increasing velocity of water flow as it exits the head. The increased speed of the water flow induces fluttering of thin and light body of the Avias's lure (comparatively to thick and heavy body of the present invention). The present invention does not include a nozzle and the fluttering of the body portion achieved by different means (combination of body portion flexibility and mass per unit length instead of combination of increasing water flow speed and body flexibility in the Avias's lure). The nozzle solution is also used in US Patent No.

2,229,239 described above.

[18] French patent No. FR 2,628,293 titled 'Flexible fish-shaped fishing lure - undulates on holder or hook placed in water flow', invented by Guillois Hubert; Lanchier J M, applied by Ragot Sa (FR), published on Sep. 15, 1989 discloses a fishing lure made of flexible material and consisting of a flexible body mounted on a holder or on a specially designed long hook. The head of the lure is weighted; the holder or the hook passes through two holes in the lure. The lure simulates undulating swimming motion of a fish when the lure moves through water. The Guillois and Lanchier's invention is different from the present one: the flexible body of the Guillois and Lanchier's lure mounted on an external longitudinal holder whereas the present invention is not mounted on any external longitudinal structure. This difference is significant because the presence of the external holder will negatively affect the attractiveness of Guillois and Lanchier's lure to fish compared with the present invention which does not have external carcass. The present invention utilizes flag flutter phenomenon as a main mechanism producing fish-like motion. It is generally known that a flag does not consist of a longitudinal holder and that the only non-fluttering structure presenting in a fluttering flag is a flagpole to which the flag is fixed. Therefore, the flexible body of Guillois and Lanchier's lure may not be regarded as the flag defined in the present description.

[19] US Patent No. 5,134,801 issued on Aug. 4, 1992 to Brian I. Davey, titled 'Fishing aid' discloses a fishing lure comprising a bulbous weighted head, a fishing hook, a skirt and hooks which engage a strip of bait or a dead fish. During towing through water the weighted head holds the lure in upright position, the skirt embraces the strip of bait or the fish and reduces the tearing effect of the water flow and the strip of bait or the fish flutters with lifelike motion. The fishing aid is different from the present invention: the present invention is artificial fishing lure constituting a single whole whereas the fishing aid is a part of a tandem fishing lure comprising an artificial structure - the fishing aid and a natural part (a dead fish or a strip of bait). The Davey's invention and the present one are also different hydro dynamically: the fishing aid embodiments comprising a strip of bait do not have a caudal fin. The technical solution of these embodiments is similar to technical solution of the invention disclosed in described above US Patent No. 1,250,189 issued to George Kinsey; the description of Kinsey's patent above provides also review of difference in technical solutions comparing with the present invention. The difference in hydrodynamic performance comparing with the present invention is also present in fishing aid embodiments comprising a dead fish. It can be seen in figure 11 in Davey's patent that the rearward end of the dead fish head located approximately in the middle of non-tapering portion of the skirt. Said head is non-bendable; therefore, an undulating wave can start only at rearward end of said head. When seeing a fishing lure comprising the fishing aid and the dead fish as a whole and comparing the fishing lure with the present invention using the same terminology and definitions (the weighted head component and the non-tapering part of the skirt in Davey's lure correspond to the head portion 1 and to the anterior body portion 6 of the present invention respectively), it can be seen that the undulation wave can start only at the middle of the anterior body portion of Davey's lure. In present invention and in a real fish the undulation wave starts at rearward end of the head (of the real fish) or at the rearward end of the head portion 1 (of the present invention); this wave propagates along all length of anterior body portions of both the real fish and the present invention.

[20] US Patent No. 6,363,651 issued on Apr. 2, 2002 to Gregory C.Garst, titled 'Fishing lure with undulating fins' describes an artificial fishing lure with undulating fins which imitates swimming motion of fish. The inventor discloses a fishing lure comprising elongated body having thin, flexible fins extending along the body of the lure. On tow through water, the fins undulate in the wave-like motion. The Garst's invention is different from the present one because in Garst's invention the only part that undulates is the fins and the lure body remains stable whereas the present invention imitates the real fish undulating body movement by undulation of the lure body, aggregation of oscillation energy and transmitting all lure oscillating body energy to caudal fin flaps.

[21] US Patent No. 5,678,350 issued on Oct. 21, 1997 to Mark H. Moore, titled 'Fish

Lure' describes a fishing lure made of industrial silicone having a three-dimensional resemblance to a fish, weighted head portion and a hinge. When the lure is drawn through water, the lure aft portion moves laterally from side to side in fish-like movements. The Moore's invention is different from the present one: the aft portion of the Moore's invention oscillates like a pendulum whereas oscillations of the present invention form a sinusoidal wave (the oscillations of the aforementioned embodiment of the Moore's invention are close to oscillations of the lure disclosed in French patent FR 1,315,834 described above). In another embodiment Moore discloses a fishing lure which is similar to the first embodiment but does not have the hinge. The oscillating part of the second embodiment of the Moore's lure is caudal region and caudal fin. The second embodiment of the Moore's lure is different from the present invention: the only part that oscillates in second embodiment of the Moore's invention is caudal region and caudal fin whereas in present invention fluttering occurs along all the length of the body. This is very significant difference because the fluttering of the present invention strongly resembles the undulation of a real fish which occurs along all the length of the fish body. It should be noted that the purpose of a real fish body undulation and of fluttering of the present invention is to accumulate as much oscillation energy as possible and then to transmit the energy to flapping of caudal fin by and through caudal region. In the Moore's invention this similarity between lure and the lure prototype is not present.

[22] US Patent No. 7,356,963, issued on Apr.15, 2008 to Jason E. Scott, titled 'Fish lure' describes an artificial fishing lure including a soft, fish-shaped body. The lure comprises two or more segments connected by an integrally-formed vertical hinge. When drawn through water, the lure segments form alternate zigzag shapes. The Scott's invention is different from the present one because the wave produced by the Scott's invention when drown in water consist essentially of the oscillations of the finite number of straight segments whereas the body wave produced by a real fish during undulation and the body wave which arises during towing of the present invention are smooth. A more detailed comparison between a zigzagging motion and a smooth undulation or fluttering provided in the paragraph describing US Patent No. 857,883 mentioned above. Also, the Scott's invention comprises vertical hinges which produce some hydrodynamic wake. The Scott's lure prototype - a real fish and the present invention do not have aforementioned hinges and wake.

[23] US Patent Application Publication No.US 2012/0055065 Al published on Mar.8, 2012, titled 'Fishing lures', invented by Clayton Camilleri describes a fishing rig for receiving a dead bait fish having a mounting body comprising a weighted support rod, an upper bar and a lower bar for abutting respectively an upper head portion and a lower head portion of the bait fish. During trolling the weight holds the lure in upright position and the body portion of the bait fish assumes undulated motion. The

Camilleri's invention is different from the present one: the Camilleri's lure comprises a dead bait fish whereas the present invention is an artificial fishing lure. The Camilleri's lure comprises significant external metal elements on the bait head whereas the present invention avoids external additions which reduce similarity between the lure and its prototype. These inventions are also different hydro dynamically: the embodiments of the Camilleri's lure disclosed in the patent application publication comprise a deflecting water flow bill. The bill surface plane interacting with the water flow lies perpendicular to the flow direction; the resistance of the bill to the water flow induces a lateral wobble. It can be seen that the technical mechanism of the wobble is completely different from the technical solution of the present invention. Embodiments of the Camilleri's lure comprising a spherical weight attached at gills juncture side instead of the bill are also different from the present invention: a real prey fish and the present invention are streamlined structures with minimal deflection of the water flow around head portion of both structures. The flag defined in the description of the present invention is only fixed at its leading edge and is not located behind any obstruction inducing drag wake. During trolling through water said spherical weight must induce a wake behind the weight. Therefore, the water flow arriving to the body portion of the Camilleri's lure will be distorted by said weight and vortices (the wake) which will be shed from the Camilleri's lure will be different from those of the present invention. Comparing with the Camilleri's lure, the wake which is shed from the present invention during towing will mimic better the wake of a real prey fish because the fluttering part of the present invention will receive an undistorted water flow.

Description Of Drawings

[24] Figure 1 is a top right isometric projection of the present fishing lure illustrating a snapshot taken during towing the lure through water.

[25] Figure 2 is a rotated orthographic projection of the present fishing lure illustrating a snapshot taken during towing the lure through water.

[26] Figure 3 is a showing hidden lines top right isometric projection of the present

fishing lure illustrating the lure as it should be produced or illustrating the lure in non- towed through water state. The figure also illustrates the rotation axis R-R and the longitudinal axis L-L.

[27] Figure 4 is enlarged view of a portion depicted by circular detail view boundary F on figure 3. The scale of figure 4 to figure 3 is 3: 1. Figure 4 illustrates snout part of the lure; more particularly, the figure illustrates relative positions of the rotation axis R-R and the longitudinal axis L-L.

[28] Figure 5 is an enlarged view of a portion depicted by circular detail view boundary E on figure 3. The scale of figure 5 to figure 3 is 3:1.

[29] Figure 6 is an enlarged view of a portion depicted by circular detail view boundary D on figure 3. The scale of figure 6 to figure 3 is 3:1.

[30] Figure 7 is a showing hidden lines right view of the lure illustrated in figure 3.

[31] Figure 8 is a front view of the lure illustrated in figure 3.

[32] Figure 9 is a back view of the lure illustrated in figure 3.

[33] Figure 10 is a top view of the lure illustrated in figure 3.

[34] Figure 11 is a bottom view of the lure illustrated in figure 3.

[35] Figure 12 a showing hidden lines right view of the lure illustrated in figure 3. The figure 12 illustrates the head portion 1, the body portion 2, the anterior body portion 6 and the caudal peduncle 7.

[36] Figure 13 is a section view cut at a plane defined by a cutting line P-P in figure 12 and viewed in direction indicated by arrows located at the ends of the cutting line. [37] Figure 14 is a section view cut at a plane defined by a cutting line K-K in figure 12 and viewed in direction indicated by arrows located at the ends of the cutting line.

[38] Figure 15 is a section view cut at a plane defined by a cutting line J-J in figure 12 and viewed in direction indicated by arrows located at the ends of the cutting line.

[39] Figure 16 is a showing hidden lines top view of the lure illustrated in figure 3.

[40] Figure 17 is a section view cut at a plane defined by a cutting line T-T in figure 16 and viewed in direction indicated by arrows located at the ends of the cutting line.

[41] Figure 18 is a showing hidden lines orthographic projection of caudal fin 3 and

stiffening means 8 illustrating the caudal fin 3 separately from the stiffening means 8.

[42] Figure 19 is a showing hidden lines exploded view of the fishing lure illustrated in figure 3.

[43] Figure 20 is a showing hidden lines exploded view of the fishing lure illustrated in figure 1.

[44] Figure 21 is a series of snapshots illustrating nine consecutive positions of the

present fishing lure during towing through water. The series comprises nine pairs of views; each pair illustrates one position and includes a rotated orthographic projection and a top view of the lure. The top pair illustrates the first position and the bottom pair illustrates the last position. The series illustrates bending wave propagating along body portion of the lure during one complete cycle of the flutter (more precisely, during one period of the flutter), so the top pair of snapshots is identical to the bottom pair.

Disclosure of Invention

Disclosure

[45] During undulation a real prey fish transmits energy of its muscles to water. The prey fish imitation - a fishing lure which is towed through water by an angler receives energy from the water hydrodynamic resistance. If the prey fish and the lure are similar in dimensions, mass, speed and undulating behavior, then the total energy in the water- lure system can be of order of the total energy in the fish- water system. The essential condition for this similarity is the lure behavior: when the lure behaves in fish-like undulating mode, then there is sufficient energy received by the lure from the water flow and the similarity occurs. The same order of energies means that the wakes (vortices) shed to water by both objects will be similar. The resemblance of dimensions, speed, behavior and similarity of hydrodynamic wakes shed into water means that the lure will become extremely attractive to a piscivorous fish.

[46] The present invention utilizes flag flutter phenomenon as the main mechanism

producing fish-like undulating motion. The body portion of the fishing lure constitutes self-supporting heavy flag which flutters and therefore produces a sinusoidal wave along all the flag length while the lure is towed through water. The caudal fin of the present fishing lure constitutes an attached to said flag propulsion blade. Moreover, the mechanism for maximizing lure bending wave speed and the means for producing powerful caudal fin flaps are disclosed.

[47] For the purpose of present description, a definition of a flag and some related terms and concepts must be specified: the flag mentioned in the present invention description is a flag having fluttering ability, the flag can be defined as a structure interacting with a moving fluid which may be in gas or liquid form; the flag has a fixed leading edge and a free trailing edge. The flag is only fixed at its leading edge and is not located behind any obstruction inducing drag wake (for example, thick flagpole). The flag length is greater than the flag thickness, also the flag width is greater than the flag thickness; the flag material must be highly elastic or highly bendable. For the present definition only, the flag length is greater or equal than the flag width. The flag mass per unit length must be heavy relatively to fluid; the term 'heavy' means that the flag mass per unit length (the flag inertia) must be sufficient to overcome the fluid flow stabilizing (straightening) forces (a 'light' flag will not flutter) and be intentionally increased when the density of fluid is increased. More specifically, the mass per unit length of a flag intended for water must be considerably higher than the mass per unit length of a flag intended for air. The fluttering ability of a flag means that that the above mentioned parameters (the combination of the flag length, width, bending stiffness or elasticity and mass per unit length) are chosen in such a way that the flag flutter phenomenon arises. The flag flutter means appearance of side-to-side oscillations of different parts of the flag in different phases; these oscillations form a sinusoidal wave which propagates from the leading edge of the flag towards the trailing edge of the flag. The directions of the flag flutter oscillations may lie on only one plane. The terms 'higher', 'highly elastic or highly bendable' and 'heavy' used in this paragraph are, of course, not strict terms; the interrelations of the corresponding parameters and method to choose them are considered in the next paragraph.

[48] A strict way to define a flag having fluttering ability would be defining it as an interacting with a fluid flow structure having length L, width 1, thickness h, made of material having Young's modulus E and having a density p. The flag must be fixed at its leading edge and free at its trailing edge. Also, density of the fluid with which the flag interacts and the fluid speed relatively to the flag must be specified. Then, in order to define the flag, the relation between the aforementioned parameters should be expressed as a strict formula or set of formulas. The exact explanation of the flag flutter phenomenon is not present in text books; this subject is examined in few advanced scientific articles two of which are presented in the present invention description. According to M.Argentina and L. Mahadevan, Fluid-flow-induced flutter of a flag, Proceedings of the National Academy of Sciences of the United States of America, (2005), and to M.Shelley, N.Vandenberghe and J. Zhang, Heavy flags undergo spontaneous oscillations in flowing water, Physical review letters, (2005) most of these parameters are interrelated and changing of one parameter must be compensated by changing of one or more other parameters in order to keep some desired result, for example a critical fluid flow speed at which the flag flutter phenomenon arises. The flag motion equations presented in these two works are different flag motion models being close approximations of this complex phenomenon. The authors of each work mention differences between the theoretical and experimental results of each flag motion model. Therefore, the strict formula or set of formulas defining the flag motion have not been revealed yet and at the present state of the scientific research on flag flutter phenomenon the flag should be defined by the desired result: the presence of the flag flutter. This means that the aforementioned parameters should be chosen experimentally. More specifically, when the fishing lure prototype-a real prey fish or some general prey fish-like structure are chosen and therefore length, width and thickness of the lure are known, it remains to set by experiment bending stiffness of the material and mass per unit length of the body portion of the fishing lure keeping in mind that the body portion must constitute a flag.

[49] It can be seen so far that the flag is defined by the presence of the flag flutter.

Therefore, the method for measuring properties and testing whether this phenomenon is present must be described. Keeping in mind the definition of flag flutter presented above, the method for testing whether this phenomenon is present should be as follows:

1. The water flow speed relatively to the flag must be in range of imitated prey fish speed relatively to water (fishermen usually know this range intuitively and therefore tow their lures within range of speed of various prey fish; it can be said that it would be sufficient to check the flag within the range of water flow speed which is regular fishing lure towing speed).

2. The sinusoidal wave propagating from the leading edge of the flag towards the trailing edge of the flag must be clearly visible to the naked eye on series of photographs taken from above (corresponding to the figure 21 in the drawings) during towing the flag through water. The wave amplitude and the wavelength may be different; the purpose of the analyzing is to assure that the wave is present.

[50] The second technical concept that should be defined is a 'smooth function' representing flutter of a flag. This definition is needed because there is a necessity to distinguish precisely the existing lures and the present invention. The 'smooth' characteristic of a sinusoidal function representing on a plane a bending wave which propagates along all the flag length means that the function must be smooth in math- ematical sense. Mathematically it means that the function has derivatives of all orders; to an observer the slope of the function appears as constantly changing. There must be done some simplifications in order to present flutter of a three-dimensional flag as a plurality of curves on a plane or as a two dimensional function: when a flag is in non- fluttering state, it has a longitudinal axis defined as central principal axis of inertia passing through center of mass of the flag and lying lengthwise. There are plurality of axial points lying on the longitudinal axis bounded by the forward edge and the trailing edge of the flag (for example, the plurality of axial points can be marked within a flag made of transparent material by a contrast thread). A describing a wave function y(xj assigning at each moment of time t to each real number belonging to the function domain one and only one number on axis y is used commonly as a part of wave equation (a differential equation describing spreading of a disturbance in a medium). The simplest example of a function representing a wave on a plane is y=sin(x+t) where t is time. It can be seen that this simplest example is a smooth function because it has derivatives of all orders. During fluttering of a flag, each point of said plurality of axial points will oscillate in different phase producing a bending wave on single horizontal plane. It can be seen that during fluttering said horizontal plane can be defined by three different arbitrary points belonging to said plurality of axial points. A describing the fluttering wave function will define the precise position of each axial point on the horizontal plane at each moment of time. Another, intuitive explanation of the

'smoothness' is that if a mathematical limit of length of each oscillating portion of a flag during fluttering is zero, this means that a function representing on a plane the bending wave is smooth and vice versa (if the function is smooth than said limit is zero). For example, the fluttering ('flapping') flag shown in Fig.3 in M.Shelley, N.Vandenberghe and J. Zhang, Heavy flags undergo spontaneous oscillations in flowing water, Physical review letters, (2005) cannot be presented by a smooth function - it is clearly visible that there are straight parts (the copper segments of the shown from above flag). The length of each oscillating part in this case is the length of each copper segment. In the same way, the flag-like motion of fishing lures disclosed in US Patent No. 857,883, US Patent No. 2,685,145, US patent No. 6,560,914 and US Patent No. 7,356,963 mentioned above cannot be described by a smooth function. Each of these lures is segmented and length of each oscillating part in each lure is the length of the corresponding segment. On the other hand, the flutter of a simple cloth flag in air is 'smooth': each point along the flag length oscillates and takes part in the flutter (mathematically, the function representing on a plane the flutter of the cloth flag is smooth, also there will be infinite number of points taking part in the flutter along all the flag length, therefore, aforementioned limit will be equal zero). In the same way, the flutter of the present invention which constitutes a single whole (the body portion 2 is unsegmented) can be described by a smooth function (see Fig.21 in the drawings). The method for checking whether a flag flutter can be described by a smooth function should be as follows:

1. If it is clear that mathematical limit of length of each oscillating portion of a flag along all the flag length during fluttering is zero, the function representing on a plane the bending wave is smooth. If it is clear that said limit is greater than zero, said function is not smooth ( for example, a function describing fluttering wave of a cloth flag is smooth, a function describing fluttering wave of a towed dead bait fish is not smooth because there are straight vertebrae constituting an axial skeleton of the fish).

2. If there is no clear answer to examination question described in preceding paragraph, the next check should be as follows: while the flag is in non- fluttering state, the longitudinal axis of the flag must be projected and clearly marked on the flag uppermost edge (hereafter 'projected axial curve'). During fluttering said projected axial curve must appear to the naked eye as smooth wave on a series of snapshots taken from above and presented in scale 1 : 1 to real size of the lure. Appear as smooth means that slope of imaginary tangent line at each point of said curve must constantly change along all length of the flag (the sinusoidal wave propagating from the leading edge of the flag towards the trailing edge of the flag must not include straight segments).

[51] Fig. 21 in the drawings (right column) corresponds to this series of photographs. Distinguishing smooth and zigzag curves is a common practice, for example spreadsheet program Microsoft Excel 2010 includes a simple option called 'Smoothed line' changing a zigzag curve in a graph into a smooth one. It can be summarized that said distinguishing lies in the domain of common art.

[52] The third technical concept that should be defined is a propulsion blade. It was

described above that in real fish caudal fin receives undulation energy of the fish body and generates thrust. Technically, the caudal fin of the fish acts as a propulsion blade: during each tail bit there is pressure difference between two sides of the caudal fin, said pressure difference induces thrust (a reaction force directed along fish trajectory); the necessary conditions for energy effectiveness of the undulating propulsion are the caudal fin shape, the fin stiffness and mass. It can be supposed that caudal fin shape generated by evolution is the most effective solution, so the remaining characteristics are caudal fin stiffness and mass. In order to transmit to water as much undulation energy as possible, the caudal fin must be relatively stiff and have minimal mass.

These characteristics are indeed found in fishes. Accordingly, the caudal fin of the present invention, whose goal is mimicking visual and hydrodynamic appearance of a real fish, constitutes a propulsion blade. The goal of the caudal fin of the present invention is the same as the goal of its real prototype-to transmit fluttering energy of the lure body portion to water (the water shed side-to-side and backward similar to a real prey fish, this visual and hydrodynamic disturbance induced by the lure will attract piscivorous fish). Therefore, the propulsion blade of the present invention should be defined as follows: there must be present a thrust generated by the propulsion blade. In order to generate a thrust, the propulsion blade of the present invention must be relatively stiff. Although the word 'stiff is not a strict term, it is generally known that artificial fin-like propulsion blades must have this feature: for example US patent No. 2,099,973 issued on Nov. 23, 1937 to M.De Corlieu, titled 'Lifesaving and swimming propelling device' discloses a rubber swim-fins comprising steel wares forming a flat armature. Present rubber swim fins also have means to stiffen the blade part; one of the simplest methods is adding ribs lying perpendicular to the blade plane (this solution disclosed in US patent No. 2,321,009 issued on Jun. 8, 1943 to O.P. Churchill, titled 'Swim-fin'; the inventor calls this feature 'reinforcing tapered beads'). Another example is a swimming monofin sometimes made of stiff thin fiberglass sheet owing to the same reason (in order to transmit energy to water and generate thrust, the blade of the monofin must be thin and stiff). It can be summarized that choosing propulsion blade stiffness lies in the domain of existing art.

[53] The fourth technical concept is a 'whole' unit. Literally, the term 'whole' means 'constituting an undivided unit'. Speaking strictly in the scope of the present patent application, the precise technical definition is that the whole flag or whole body portion are not hinged. The precise logical explanation is as follows: if some unit is hinged, then it is divided into segments; hence, if some unit is whole (undivided into segments) then it is not hinged. An equivalent technical definition is that the whole unit does not have pivoted connections dividing the unit into segments. A 'whole body portion' does not have any hinges or pivoted connections dividing said portion into segments and thus making the body portion more flexible at the hinge axes or at the pivoted connections. For example, the body portion of lure disclosed in US Patent No. 7,356,963 presented above comprises hinges dividing lure body portion into segments and therefore is not 'whole' in the scope of the present patent application. Another example is the fluttering ('flapping') flag shown in Fig.3 in M.Shelley, N.Vandenberghe and J. Zhang, Heavy flags undergo spontaneous oscillations in flowing water, Physical review letters, (2005) which is not a whole flag - it is clearly visible that there are hinged segments (the copper segments of the shown from above flag). An example of a whole unit is a cloth part of a simple cloth flag attached to a flagpole and fluttering in a breeze. If there are some non-bendable elements added to a checked unit, the examination whether the unit is whole should be done assuming that the unit does not comprise these elements. An equivalent of the 'whole' characteristic of a flag is a 'hinged-free' feature of a flag. Although the hinged-free characteristic is negative literally, it is one of precise terms available and suitable for characterizing a flag. For this reason the term 'hinged-free' is used in scientific literature (see for example the first paragraph of the article M.Argentina and L. Mahadevan, Fluid-flow-induced flutter of a flag, Proceedings of the National Academy of Sciences of the United States of America, (2005), also the term 'hinged-free' is often used in scientific articles in beam vibration descriptions).

Detailed description of the invention

[54] The present fishing lure resembles a real prey fish in three dimensions and comprises a head portion 1 constituting a flag mounting means, a whole body portion 2 constituting a flag, a caudal fin 3 constituting a propulsion blade and a hook 5. Like a real prey fish, the lure is substantially streamlined (supposing that the straightened lure is rigid and placed in a water flow). The head portion 1 and a body portion 2 made of very soft plastic and the body portion 2 is molded as a whole unit . The head portion 1 comprises a hook 5 and a weight 4. The metal weight 4 is molded along the hook shank. The lure has a longitudinal axis L-L passing through forward tip of the lure snout. Strictly speaking, a longitudinal axis is one of the 3 central principal axes of inertia. In the present description, the longitudinal axis L-L of the lure defined as central principal axis of inertia supposing that the lure density is homogenous. Another axis is a rotation axis R-R (relevant only during towing the lure through water) passing through leading end of the hook 5 eye constituting an eyelet 12; the rotation axis R-R is tangent to a fishing line attached to said leading end at the point of attachment (although in the preferred embodiment the longitudinal axis L-L and the rotation axis R-R lie very close one to another, they must be treated separately because the eyelet 12 and therefore also the rotation axis R-R can be located on the forehead side 13 with the same effect on the lure hydrodynamic performance). Without means to prevent rotation round the rotation axis R-R as described below, the lure will rotate on tow through water. When choosing the position of weight 4 in the head portion 1 the relative position of the eyelet 12 must be taken into account: in order to keep the head portion 1 in the right rolling position and to apply righting torque on the body portion 2, the center of gravity of the weight 4 must lie below the rotation axis R-R relatively to forehead side 13 and to gills juncture side 14. On towing trough water, the lure will at first become straight along the longitudinal axis L-L; the location of the weight 4 below the rotation axis R-R will induce righting torque round the rotation axis. More specifically, because the weight 4 and therefore the center of gravity of the head portion 1 located below the center of buoyancy of the head portion 1 and below the rotation axis R-R there will be strong righting torque applied to the head portion 1 and to the body portion 2. During towing through water this righting torque will keep the head portion 1 in the right stable rolling position-the forehead side 13 will be above the lure longitudinal axis L-L and the gills juncture side 14 will be below the longitudinal axis. The pouring of the head portion 1 and the body portion 2 into a mold consists of two steps: first a ventral portion 16 is poured. The ventral portion 16 starts at the forward end of the head portion 1, ends at the rearward end of the body portion 2 and lies below the longitudinal axis L-L. The second step is pouring of the dorsal portion 15. The dorsal portion 15 starts at the forward end of the head portion 1, ends at the rearward end of the body portion 2 and lies above the lure longitudinal axis L-L.

Before pouring the ventral portion 16, powdered filler must be added to the liquid plastic. The filler must not reduce considerably the elasticity of the molded plastic. The dorsal portion 15 made of the same plastic as the ventral portion 16 but does not contain the powdered filler. The purpose of the filler is increasing the density of the molded plastic of ventral portion 16. Figures 14 and 15 illustrate cross-sections of the lure along the lines K-K and J-J on figure 12. It can be seen that the center of buoyancy is situated around the longitudinal axis L-L. The increased density of plastic of the ventral portion 16 relatively to the density of plastic of the dorsal portion 15 leads to displacement of the center of gravity of the body portion 2 to the ventral portion 16. The displaced center of gravity of the body portion 2 will be located below the center of buoyancy of said body portion, therefore there will be righting torque round the longitudinal axis L-L. The combined aforementioned righting torque of the head portion 1 and the righting torque of the body portion 2 will keep the lure in the right position relatively to water surface: during towing through water the dorsal portion 15 will be above the longitudinal axis L-L and the ventral portion 16 will be below the longitudinal axis L-L. During towing through water, the head portion 1 comprising the relative heavy weight 4 and the hook 5 will be relatively stable and will not oscillate significantly in a pendulum- like mode because this portion is unbendable and because of the oscillations of the adjacent body portion 2 which will apply stabilizing

(straightening) forces on the head portion 1 along the longitudinal axis L-L. Besides the mimicking objective, the first purpose of the head portion 1 is to be a mounting means for the body portion 2 constituting a flag. The second purpose of the head portion 1 is to apply strong righting torque on the body portion 2 in order to prevent it from rotating round the rotation axis R-R. Also, the weight 4 will allow the angler to cast the present lure as far as possible. It can be seen in the figure 1 and in figure 2 that the present fishing lure corresponds to a real prey fish prototype in three dimensions. Therefore, the mass per unit length of the body portion 2 must be considered as 'heavy': if one considers the body portion 2 as a flag which is fixed to the non-rotating head portion 1 and supposes that the flag is made of thin cloth, than at the same speed, maintained by human-hand towing, the flag will flutter in air flow but will not flutter in flow of water. In present invention the body portion 2 made of a very flexible plastic having density which is similar to that of water. Also, the cross sections along the lines K-K and J-J, illustrated in figures 14 and 15 show that the body portion 2 is relatively thick. Therefore, the thick plastic body portion 2 is considerably heavier than the hypothetical thin cloth flag corresponding to the body portion 2. It can be summarized in light of the flag definition in present description that the body portion 2 has a mass per unit length which is 'heavy' relatively to water and that the body portion 2 is suitable for the arising of flag flutter phenomenon. It can be seen that during towing through water the body portion 2 constitutes a thickened heavy flag which is attached to the non-rotating and non-oscillating head portion 1 provided that the plastic body portion 2 is extremely flexible. The flexibility should approximately correspond to a flexibility of a non-contracted fish or animal muscle tissue. One example of this necessary characteristic is the flexibility of ballistic gelatin. An example of suitable sort of plastic will be disclosed in the 'best mode for carrying out the invention' part of the present description. It can be seen that the flag flutter phenomenon will arise on the body portion 2 during towing through water. The appearance of the flag flutter along the body portion 2 means that there will be lateral side-to-side oscillations of different parts of the body portion 2 in different phases; these oscillations will form a sinusoidal wave propagating from the adjacent to the head portion 1 forward end of the body portion 2 towards the rearward end of the body portion 2. Starting from the forward end of the body portion 2 and ending at the rearward end of said body portion, oscillation of each point on this path will add energy to the fluttering body portion 2. Two major components of the flutter must be taken into account: the first is constant presence, interchanging and displacement from the leading end of the body portion 2 towards the rearward end of said body portion of concave and convex side of the travelling along the body portion 2 bending wave (it can be seen in figure 21). The constant presence, interchanging and displacement of the concave and the convex sides means that there will be constant pressure differences along the body portion 2. Said pressure differences will add energy to the undulating body portion 2 along all its length. The second component is conservation of momentum of each oscillation producing travelling along the body portion 2 pulses. More specifically, each subsequent point of this fluttering path will add energy to the body portion 2 and receive energy from preceding point. It can be modeled as if a first small part of body portion 2, represented here as a point and located near forward end of the body portion 2 oscillates and therefore produces a first pulse which travels as a wave from the point of oscillation towards the rearward end of the body portion 2. The second point located on the first pulse path oscillates in phase with the first oscillation producing a second pulse which travels as a wave towards the rearward end of body portion 2. It can be seen that during fluttering these two pulses or waves are coherent with zero difference in phase. The coherence of the waves with zero difference in phase means that there will be a constructive interference or summation of energies of these waves. Therefore, at a third point located on the second pulse path, these two pulses will form a single wave carrying the combined energy of these two pulses. The adjacent to the head portion 1 body portion 2 comprises an anterior body portion 6 and a caudal peduncle 7. The anterior body portion 6 corresponds to same portion of a real fish body-this is a portion starting at rearward end of the head portion and ending at the rearward end of the fish anal fin. The caudal peduncle 7 corresponds to a caudal peduncle of the real fish-this is the part of the fish body starting at the rearward end of the anal fin and ending at rearward end of the body of the fish. The purpose of the anterior body portion 6 is accumulation of as much flutter energy as possible. The purpose of the caudal peduncle 7 is transmitting the flutter energy to the caudal fin 3. The caudal peduncle 7 has a diminishing width and thickness, the cross-sections of the caudal peduncle 7 starting from the line J-J in figure 12 can be presented as a series of ellipses-like cross-sections whose surface area is continuously diminishing. The caudal fin 3 made of transparent stiff and thin plastic and comprises caudal fin fixation means 21 having a hole. In the preferred embodiment of present invention said caudal fin fixation means 21 is significantly lengthened and this plastic strip constitutes a different important component- a stiffening means 8. Before pouring, the caudal fin 3 together with the stiffening means 8 should be placed inside the mold and a flexible and inextensible cord 9 connecting between along the longitudinal axis L-L the weight 4 and the aperture 17 should be firmly attached or tied to said weight 4 and to said aperture. During fluttering, the energy of all oscillations of the anterior body portion 6 arrives to a part of the lure, referred as cutting line J-J on figure 12, then, all this energy must be transmitted to the caudal fin 3 with maximal speed. The means for the speed maximizing are the stiffening means 8 which should be joined to the caudal fin 3. The purpose of the stiffening means 8 is to stiffen the caudal peduncle 7. Because of the stiffening means 8, the caudal peduncle 7 is relatively stiff er than the anterior body portion 6 and the bending wave wavelength and speed are not diminished during propagation along the caudal peduncle 7 (the tapering caudal peduncle 7 is thinner than the anterior body portion 6 - this means that without the stiffening means 8 , the bending stiffness of the caudal peduncle 7 will be less than that of anterior body portion 6 and therefore the bending wave wavelength along the caudal peduncle 7 will be shortened at the expense of the increased amplitude of the bending wave; the shortening of the bending wave wavelength along the caudal peduncle 7 means that without the stiffening means 8 the speed of said wave part along the caudal peduncle 7 will be decreased). Another explanation is that a change in the properties of the medium will cause a change in the wave speed, increasing amplitude of the wave propagating along the caudal peduncle 7 means that the wave energy will be dampen by external water flow drag. Therefore, stiffening the caudal peduncle 7 will allow transmitting the wave energy to the caudal fin more effectively: the amplitude will be lower and the wavelength and the speed of the wave will be greater. Some of the most effective swimmers like Atlantic bluefin tuna or great white shark have an anatomic feature whose goal is to stiffen caudal peduncle-it is so called caudal keel. Another example is an oar- it is obvious that the shaft must be rigid. One in a small boat can propel him/herself just with an oar blade but the blade attached to a shaft is a better technical solution. The physical principle of these examples is the same: once the oscillation energy has been generated, it must be transmitted to a propulsion blade as effective as possible (in order to conserve the energy, the transmitting means must be light- weighted, and rigid or stiff). The stiffening means 8 is defined as follows: it is situated along longitudinal axis L-L, the length of stiffening means 8 is equal to the length of caudal peduncle 7, after adding the stiffening means 8, the body portion 2 must continue to constitute a flag; the stiffness of the caudal peduncle 7 must have been increased. Stiffening different parts of a beam transmitting a momentum along its length is well known: for example a fly-fishing rod designed to cast a fly-line is intentionally stiffened in its butt part in order to distribute equally the load as an angler casts the fly-line (there are more elastic filaments in the butt part than in the tip part of the rod, so the butt is stiffer). These features of a fly-fishing rods described in Spolek, G.A., 'Measurement of Fly Rod Spines,' Proceedings of the SEM Annual Conference on Experimental and Applied Mechanics, Portland, OR. (2005). It can be summarized that stiffening a part constituting a transmitting moment beam lies in a domain of common art. The purpose of the apertures 11 and 17 is to be fixation means for the caudal fin 3 and for the stiffening means 8 within the poured lure; also aperture 17 serves as means for attaching a flexible, inextensible cord 9 whose purpose is maximizing bending wave frequency and speed and thus increasing attractiveness of the lure to piscivorous fish. It can be supposed that a real prey fish maximizes caudal fin flapping frequency in order to propel efficiently; accordingly, the caudal fin flapping frequency of the present invention must be as high as possible. After adding the cord 9, the body portion 2 must continue to constitute a flag. The cord extensibility must be negligible comparatively to extensibility of the body portion 2. The frequency of side-to-side oscillations of different points along body portion 2 will increase because the body portion 2 with the cord 9 inside will be inextensible. The wavelength of the bending wave will increase too. The body portion 2 is made of a very soft plastic, therefore the body portion 2 will be highly extensible. The high extensibility of said body portion means that without means to prevent the extensibility, the bending wave speed along the body portion 2 (which is wavelength times wave frequency) will be diminished. It was described above that the very significant part of a flag flutter is the momentum conservation. Therefore, if the flag material is highly extensible, then it will take more time comparative to a flag made of inextensible material for the propagating pulse to accelerate the subsequent part of the pulse path. The more time taken for the acceleration means that the pulse propagation speed (the bending wave speed) of a flag made of extensible material will be diminished comparatively to a flag made of inextensible material. The inextensible cord 9 prevents the body portion 2 from extension keeping the bending flexibility of said body portion; therefore the wave speed along the body portion 2 will be as high as possible.

[55] During towing through water, the head portion 1 will be in the right position-the forehead side 13 will be above the longitudinal axis L-L and the gills juncture side 14 will be below said axis. The body portion 2 constituting a heavy flag will flutter while the dorsal portion 15 will be above the longitudinal axis L-L and the ventral portion 16 will be below said axis. All the flutter energy of the body portion 2 will arrive to the caudal fin 3 at maximum possible speed. The maximum possible speed will be achieved owing to the means for maximizing the wave speed (the cord 9) and by the means for keeping the wave speed along the caudal peduncle 7 (the stiffening means 8). The mass of the portion of the stiff caudal fin 3 impacting with water is very low, therefore, because of the energy conservation law, all the oscillation energy of the body portion 2 constituting the energy of bending wave will be transformed into the powerful caudal fin 3 flaps which will move side by side and backwards a relatively big amount of water whose mass and backward speed will correspond to the whole body portion 2 fluttering energy. Thus, the caudal fin 3 will act as a propulsion blade transmitting the flag flutter energy to water. It can be seen that the behavior of the present fishing lure will resemble very closely the undulating behavior of a real prey fish.

[56] It should be taken into account that the aforementioned detailed description of the present invention presents the preferred embodiment. The term 'body portion' mentioned in the present description means 'a fish or a fish model body apart of the head and the fins'. The body portion dimensions can be various dimensions corresponding to a real prey fish which is mimicked by the present fishing lure. More specifically, the relationship between the body portion length, height and width must be in the range of relationships starting from proportions of a crucian carp (Carassius carassius L.j and ending by proportions of a garfish ( Belone beloneL.). Ά real prey fish' means any species of prey fish which uses undulating method of propulsion combined with using a caudal fin as a propelling means. The forward end of the caudal fin must start at the rearward end of the real prey fish body portion. In the present de- scription, for example, a perch and a roach considered as 'real prey fish' whereas an eel, a sea horse and a ray do not. The present fishing lure is an artificial one: this means that the lure made of synthetic material and metals and that it does not comprise natural elements (for example bait fish or animal muscle tissue). The material which can be used for the body portion 2 can be plastisol, silicone, rubber, polyurethane or the like. It was noted above that at first the dimensions of the lure must be chosen (the length, the width and the thickness) and after that it is remains to set by experiment bending stiffness of the material and mass per unit length of the body portion 2 keeping in mind that the body portion 2 must constitute a flag. The total bending stiffness of the body portion 2 depends on the Young's modulus of the material of which said body portion 2 is made and it proportional to the thickness of said body portion. Therefore, if the material of which the body portion 2 is made is stiff and the flag flutter phenomenon does not arise at the desired towing speed, the thickness of said body portion 2 must be diminished to decrease the total bending stiffness of said body portion 2. Decreasing the thickness of said body portion 2 means that the mass per unit length of the body portion 2 will be decreased too and the body portion 2 will cease to be a 'heavy' flag. Therefore, in order to keep the fluttering ability of the body portion 2 which must constitute a flag, the mass per unit length must be increased; instead of the powdered filler mentioned in the preferred embodiment which will not be sufficient in this case, there can be used small metal balls or the like incorporated in line parallel to the longitudinal axis L-L in the ventral portion 16. The purpose of these metal balls or the like in this case is to increase the mass per unit length of the body portion 2 applying righting torque round the longitudinal axis L-L. It can be

summarized that the body portion 2 can be made of different flexible materials using different methods to keep the bending stiffness and mass per unit length of the body portion 2 suitable for the arising of the flag flutter phenomenon at the desired towing speed. In the preferred embodiment, the weight 4 is molded along the hook 4 shank, the weight 4 is fully embedded in the head portion 1 and the hook 5 projects from the ventral portion 16. Keeping in mind described in the present description technical purpose of the head portion 1, various technically equivalent embodiments of the head portion 1 can be imaginable. For example, the weight 4 can be partially embedded or be attached externally to the head portion 1, the head portion 1 can be made of metal with the eyelet 12 located on the forehead side 13 and the hook 5 projecting from the gills juncture side 14 or from the forehead side 13 (the external metal head applying righting torque on a lure and attached to a flexible lure body is commonly used and called a ig head'). The presence of the flexible and inextensible cord 9 and the stiffening means 8 is not indispensable; although the present fishing lure will be less attractive for the piscivorous fish without these features, the remaining features charac- terizing the lure-the body portion 2 constituting a flag and the caudal fin 3 constituting a propulsion blade are basic lure features enabling to use the lure and lying beyond the prior art. The presence of the caudal fin fixation means 21 is not indispensable: in less preferred embodiments (without the stiffening means 8) the caudal fin 3 can be attached to the body portion 2 in various other ways. The adding of the powdered filler described above is not indispensable: the weight 4 may be so massive that the righting torque it applies will be sufficient to keep not only the head portion 1 at the right rolling position during towing through water, but also to keep at the right rolling position the whole body portion 2. If the mass of the weight 4 is not sufficient to keep the body portion 2 at the right rolling position during towing through water, left side or right side of the lure will be one above the other during towing (the plane of the blade of caudal fin 3 will be parallel to the plane of the water surface). During towing in this position the lure can be viewed as a wounded prey fish by a piscivorous fish, even if this position makes the lure less attractive than position of the towed lure described in the preferred embodiment (with or without flexible and inextensible cord 9 and the stiffening means 8), the remaining features characterizing the lure-the whole body portion 2 constituting a flag and the caudal fin 3 constituting a propulsion blade are basic lure features enabling to use the lure and lying beyond the prior art.

Best mode for carrying out the invention

[57] The present fishing lure corresponds to a real prey fish (for example, a European roach Rutilus rutilus L.) in three dimensions and comprises a head portion 1, a body portion 2, a caudal fin 3 and a hook 5. Both the head portion 1 and the body portion 2 made of plastisol using the same mold and the resulted molded structure constitutes a whole unit. The non-fluttering head portion 1 made of stiff durable PVC plastisol in order to increase durability of the lure (there is extreme load jump during casting the lure by a fishing rod; increasing durability of the head portion 1 holding the weight 4 connected through durable cord 9 and stiffening means 8 with caudal fin 3 will increase significantly overall robustness of the lure). The length of the lure is 0.1 meters (the combined length of the head portion 1 and the body portion 2). The bending stiffness of the preferred plastic intended for body portion 2 must correspond approximately to bending stiffness of 15% gelatin. The 15% gelatin made from 85% water and 15% pure gelatin (by mass) which can be found in food stores. The water must be about 37 degrees Celsius, after adding the gelatin the mixture needs to be stirred for about 20 minutes until the gelatin fully dissolves. After that the mixture needs to be poured into oiled mold and chilled at about 4 degrees Celsius for 24 hours. The plastisol used to prepare the body portion 2 is PVC plastisol into which a special PVC plastisol softener is added. Before pouring, the softener should be added to the liquid plastisol and the mixture needs to be heated to temperature around 180 degrees Celsius - 200 degrees Celsius. The best way to compare the bending stiffness of the 15% gelatin and of the finished plastisol is to compare both materials poured into same mold. The comparing can be subjective; if the ready plastic appears to be stiffer than the 15% gelatin, more softener must be added and vice versa. In any case the finished lure needs to be checked in water basin by towing the lure through water. The lead weight 4 should be molded along the hook 5 shank. The caudal fin 3 made of thin stiff transparent plastic; this plastic must not be fragile; the best example of necessary bending stiffness is bending stiffness of caudal fin of the lure real prototype (this comparison can be subjective). The stiffening means 8 is made together with the caudal fin 3 of the same stiff plastic. The thickness of the caudal fin 3 and the stiffening means 8 should be about 0.0006 meters. The width of the stiffening means 8 is around 0.0015 meters and its length is equal to the length of the caudal peduncle 7. The cord 9 made of durable 100% polyester thread. The 100% polyester thread is chosen because its shrinkage during pouring of plastisol heated to 180 degrees Celsius -200 degrees Celsius is insignificant. Also, this thread is very durable. The head portion 1 is poured while the mold is positioned in such a way that the longitudinal axis of the mold (which is identical to the longitudinal axis L-L of the lure) lies vertically and the cavity corresponding to the lure snout is positioned below the cavity corresponding to the lure caudal fin. Before pouring the body portion 2, the lure mold should be positioned in such a way that the longitudinal axis of the mold lies horizontally and the cavity corresponding to the ventral portion 16 lies below the longitudinal axis of the mold and the cavity corresponding to the dorsal portion 15 lies above the longitudinal axis of the mold. After that the plastisol is heated and divided into two parts. The first part is plastisol intended for the ventral part of the body portion 2 (ventral portion 16 except part of the head portion 1 which was made separately as described above). After heating a powdered salt must be added to the first part of plastisol in proportion 10 to 4 of plastisol to powdered salt (by mass). The powdered salt is the powdered filler increasing density of the ventral portion 16. The salt must be powdered because otherwise it will not be suspended in the heated plastisol and sink. After that the second part of plastisol should be poured. Each of subsequent poured portions should be poured before full cooling of the precedent portion-in this way each portion will be 'fused' with another and the ready molded lure will constitute a single whole. Ending making of the lure, two decorative eyes 18 should be attached to the head portion 1. After cooling the lure must be checked by towing through water. The best way is a water tunnel where the speed of water flow can be measured. The parameters that must be checked are presence of flag flutter and right rolling position of the lure.

Reference signs 1. Head portion

2. Body portion

3. Caudal fin

4. Weight

5. Hook

6. Anterior body portion

7. Caudal peduncle

8. Stiffening means

9. Cord

10. Aperture

11. Aperture

12. Eyelet

13. Forehead side

14. Gills juncture side

15. Dorsal portion

16. Ventral portion

17. Aperture

18. Eye

19. Tie

20. Tie

21. Caudal fin fixation means