WO2007000394A1

WO2007000394A1 - Swim fin

Info

Publication number: WO2007000394A1
Application number: PCT/EP2006/063277
Authority: WO
Inventors: Stig Kristensson
Original assignee: Stig Kristensson
Priority date: 2005-06-27
Filing date: 2006-06-16
Publication date: 2007-01-04
Also published as: SE0501512L

Abstract

A swim fin (10) for swimming, diving and/or snorkeling. The swim fin (10) comprises a foot-pocket portion (20) and a fin portion (30). The fin portion (30) is attached to the foot-pocket portion (20) for forming an extension of the foot-pocket portion (20). The swim fin (10) allows for leg movements in directions which may be different from the traditional flutter-like aquatic kicking sequence, where the legs of a swimmer normally move in substantially opposite directions and alternately through upwards and downwards strokes.

Description

Title of the Invention

SWIM FIN

Technical Field of the Invention The present invention relates to the field of swim fins for swimming, diving and/or snorkeling.

Description of Related Art

The use of swim fins to aid in propelling a swimmer through water has been in existence for several years. Generally, a conventional swim fin may comprise a foot- pocket portion having a generally hollow interior for receiving at least a portion of the swimmer's foot therein. A relatively broad and generally flat, fin-like or blade- like member is attached to the foot-pocket portion. The fin-like member generally extends out forwardly from a front end of the foot-pocket portion such that it forms an extension of the swimmer's foot.

When utilizing such pair of swim fins, the swimmer normally executes a flutter-like aquatic kicking sequence, where the legs of the swimmer move in substantially opposite directions and alternately through both upwards strokes and downwards strokes. This traditional kicking sequence is at least partially effective to aid the swimmer in propelling through water. Therefore, conventional swim fins are so widely used that their advantages are rarely questioned. However, it has turned out that there are a number of deficiencies or disadvantages with these swim fins. For example, these swim fins may be disadvantageous when swimming in ground water or when swimming near the surface of the water. The French publication FR-A-2, 805, 470 discloses another swim fin, which is intended for aquatic muscular exercises. This swim fin consists of a shoe for receiving a foot of a swimmer and a fin attached to the shoe. The fin is positioned under the sole of the shoe and thereby forms an extension of the swimmer's leg. This swim fin involves a number of deficiencies or disadvantages. For example, a swimmer wearing a pair of such swim fins on the feet cannot walk on land or on a sea bottom. It therefore seems that there is a need for an improved swim fin that seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies or disadvantages in the art, singly or in combination. It is with respect to these considerations and others that the present invention has been made.

Summary of the Invention

It is an object of the present invention to provide an improved swim fin, which allows for alternative leg kicking movement patterns.

This is accomplished by a swim fin, which allows for leg movements in directions which may be different from the traditional flutter-like aquatic kicking sequence, where the legs of a swimmer normally move in substantially opposite directions and alternately through both upwards and downwards strokes .

According to an embodiment of the invention, a swim fin is provided. The swim fin comprises a foot-pocket portion and a fin portion. The foot-pocket portion comprises a bottom surface and a front end intended for receiving a toe portion of a foot. The fin portion comprises at least one web portion attached to the foot- pocket portion. The at least one web portion is configured to extend out forwardly in a longitudinal direction from the front end of the foot-pocket portion. A plane of the bottom surface and a plane of the at least one web portion are configured to cross each other in a line extending in the longitudinal direction.

The at least one web portion may, for example, be attached to the foot-pocket portion at the front end of the foot-pocket portion.

The bottom surface and the at least one web portion may be arranged along a joint axis given by the line extending in the longitudinal direction. Furthermore, the plane of the bottom surface and the plane of the web portion may be arranged to one another by an angle α in relation to one another. The angle α may be approximately 45° or more, e.g. about 90°.

The web portion may take a variety of different structural configurations . The web portion may be relatively soft and flexible. The web portion may be made of a composition of natural rubber and plastic. The web portion may alternatively be made of a Thermoplastic Elastomer (TPE) .

The web portion may comprise first and second rim members. Furthermore, the web portion may be positioned in between the first and the second rim members . The first rim member may be attached to the bottom surface of the foot- pocket portion, whereas the second rim member may be attached to an upper surface of the foot-pocket portion. According to another embodiment of the invention, a swim fin is provided. The swim fin comprises a foot-pocket portion and a fin portion. The foot-pocket portion comprises a bottom surface and a front end intended for receiving a toe portion of a foot. The fin portion comprises four web portions attached to the foot-pocket portion. Furthermore, the web portions are configured to extend out forwardly in a longitudinal direction from the front end of foot-pocket portion. A plane of the bottom surface and the different planes of the four web portions are configured to cross each other in a line extending in the longitudinal direction.

The four web portions may, for example, be attached to the foot-pocket portion at the front end of the foot- pocket portion.

The bottom surface and the four web portions may be arranged along a joint axis given by the line extending in the longitudinal direction. The plane of the bottom surface and the plane of a first web portion, of said four web portions, may be arranged to one another by an angle α in relation to one another. This angle α may e.g. be approximately 45°. Furthermore, the planes of the different web portions may be arranged to one another by an angle β in relation to one another. For example, the angle β may be approximately 90°.

The four web portions may take a variety of different structural configurations. The web portions may be made of a relatively soft and flexible material. The web portion may be made of a composition of natural rubber and plastic. The web portion may be made of a Thermoplastic Elastomer (TPE) . Each of the web portions may comprise a respective rim member. Furthermore, the rim member of the first web portion and the rim member of the second web portion may be attached to the bottom surface of the foot-pocket portion, whereas the rim member of the third web portion and the rim member of the fourth web portion may be attached to an upper surface of the foot-pocket portion.

Further embodiments of the invention are defined in the dependent claims .

It should be emphasized that the term "comprises/comprising" when used throughout this specification and claims is taken to specify the presence of stated features, integers, or components but does not preclude the presence or addition of one or more other features, integers, components or groups thereof.

It should also be emphasized that the term "swimmer" when used throughout this specification and claims is taken to specify swimmers as well as snorkelors and divers. Accordingly, the term "swimmer" should not be construed restrictively, but rather as an example of a contemplated user of the swim fin.

Brief Description of the Drawings

Further objects, features and advantages of the present invention will appear from the following detailed description of embodiments of the invention, reference being made to the accompanying drawings, in which:

Fig. IA is a side perspective view of a swim fin according to an embodiment of the invention attached to the foot of a swimmer;

Fig. IB illustrates the swim fin of Fig. IA in a swim position; Fig. 1C is a front perspective view of the swim fin of Fig. IA;

Fig. ID illustrates, in front perspective view, an alternative shape of the swim fin of Fig. IA. Fig. 2A is a perspective view of a swim fin according to another embodiment of the invention;

Fig. 2B is a front perspective view of the swim fin of Fig. 2A.

Detailed Description of Embodiments

Figs. 1A-1C illustrate a swim fin, generally denoted 10, according to an embodiment of the present invention. The swim fin 10 is generally intended to be used in pairs, such that two swim fins 10 are removably attached to two feet of a swimmer. For simplicity of presentation, both the structural and operative features of each swim fin 10, of a pair of such swim fins, will however be described with reference to a single swim fin. The dimension, configuration and structural features of each swim fin 10, of the pair of swim fins, may substantially correspond to one another. Thus, the two swim fins in a pair of swim fins may be identical, or be mirror images of each other.

The swim fin 10 comprises a foot-pocket portion, generally denoted 20, which is configured to be removably attached to or mounted on a foot of a swimmer. The foot- pocket portion 20 may comprise a substantially hollow interior 21. The interior 21 may be dimensioned and configured to receive and at least partly surround a portion of the swimmer's foot or the entire foot. Alternatively, the hollow interior 21 may be dimensioned and configured to receive and at least partly surround a swimmer' s foot as well as a portion of the swimmer' s lower leg.

A body 22 of the foot-pocket portion 20 may be formed into a shoe-like, boot-like or slipper-like foot pocket such that the swimmer may pass his/her foot through an opening 23 into the hollow interior 21 of the foot- pocket portion 20. As is illustrated in Figs. 1A-1C, the body 22 may have a bottom surface 24, e.g. a sole, and an upper surface 25. Furthermore, the body 22 may be made of a composition of natural rubber and plastic, for example

Thermoplastic Elastomers (TPE) . The proportion between the natural rubber and the plastic, respectively, in the composition may be chosen in dependence of the desired rigidity of the body 22. Furthermore, the proportion between the natural rubber and the plastic may vary at different sections of the body 22, so as to obtain different degrees of rigidity at different sections of the body 22. Yet further, the composition may comprise different types of rubber and plastic, respectively. Optionally, silicon may also be included into the composition. It should however be emphasized that the material selection and rigidity of the foot-pocket portion 20 is e.g. dependent on the intended use of the swim fin 10 and the specific needs of the swimmer. For example, some swimmers may prefer a relatively soft body 22 so as to obtain e.g. foot comfort. On the other hand, others may prefer a rigid body 22 so as to obtain additional support to the foot of the swimmer. Thus, considerations regarding material selection and rigidity of the body 22 must be tested and evaluated in each specific case. However, it has turned out that it may be advantageous to provide a relatively rigid body 22.

It should be noted that the foot-pocket portion 20 may take a variety of alternative structural configurations other than the shoe-like or slipper-like foot pocket as shown in Figs. lA-lC. For example, the interior 21 may be shaped to only engage the frontal portion of the swimmer' s foot and comprise an at least partially detachable or moveable retaining strap located as at 26 and being disposed in overlying relation to a heel of the swimmer's foot. The primary objective of such retaining strap would be to secure the foot-pocket portion 20 operatively on the swimmer's foot for the use of the swim fin 10. The swim fin 10 further comprises a fin portion, generally denoted 30. In general, the fin portion 30 comprises a web portion 31, which may be relatively broad and generally flat. As can be seen from Figs. IA and IB the transversal dimension of the web portion 31 may increase as the distance D from the foot-pocket portion 20 increases.

The length L of the web portion 31 may e.g. be 10-70 cm. It may be advantageous to provide the web portion 31 with a length L, which is substantially equal to the length 1 of the foot-pocket portion 20. Furthermore, the width W of the web portion 31 at the substantially outermost end of the web portion 31 may e.g. be 5-70 cm. In this regard, it should be noted that it may be advantageous to provide a web portion 31 with a width W, which is approximately 80 percent of the length 1 of the foot-pocket portion 20. Accordingly, if the swim fin 10 is provided with a foot- pocket portion 20 having a length 1 of approximately 25cm (substantially corresponding to a shoe size of EUR 42), it may be advantageous to provide the web portion 31 with a length L of approximately 25cm and a width W of approximately 20cm. Moreover, the web portion may e.g. have a thickness t of approximately 1-5 mm.

However, it should be noted that the fin portion 30 may take a variety of alternative structural configurations other than that of Figs. lA-lC. One possible alternative is shown in Fig ID. The web portion 31 may be made of a relatively soft and flexible material. For example, the web portion 31 may be made of a composition of natural rubber and plastic, e.g. Thermoplastic Elastomers (TPE). The proportion between natural rubber and plastic, respectively, in the composition may be chosen e.g. in dependence of the desired flexibility characteristics of the web portion 31. Furthermore, the proportion between natural rubber and plastic may vary at different sections of the web portion 31, so as to obtain different degrees of softness and/or flexibility at different sections of the web portion. Yet further, the composition may comprise different types of rubber and plastic, respectively. Optionally, silicon may also be included into the composition. It should however be emphasized that the material selection, softness and/or flexibility of the web portion 31 is e.g. dependent on the intended use of the swim fin 10 and the specific needs of the swimmer. These considerations should therefore be tested and evaluated in each specific case.

The web portion 31 of the fin portion 30 may e.g. be attached to the foot-pocket portion 20 at a front end 27 of the foot-pocket portion 20. The front end 27 of the foot-pocket portion 20 is intended for receiving at least a portion of a toe portion of the swimmer's foot. A longitudinal direction is given by a longitudinal axis of the bottom surface 24, the longitudinal axis being defined by the distance d from a rear end 28 to the front end 27 of the bottom surface 24. The web portion 31 is configured to extend out forwardly in the longitudinal direction from the front end 27 of foot-pocket portion 20. Thus, the web portion 31 may serve as a longitudinal extension of the foot-pocket portion 20.

As is illustrated in the figures, the plane of the bottom surface 24, i.e. the sole of the foot-pocket portion 20, and the plane of the web portion 31 are configured to cross each other in a line extending in the longitudinal direction. Thus, the bottom surface 24 and the web portion may be arranged along a joint longitudinal axis A given by the line extending in the longitudinal direction. The plane of the bottom surface 24 and the plane of the web portion 31 may thus be arranged to one another by an angle α in relation to one another. Accordingly, the web portion 31 may be configured to extend in a plane, which is different from the plane given by the bottom surface 24 of the foot- pocket portion 20. The configuration and orientation of the web portion 31 is consequently such that it extends in a plane, which does not correspond with the plane given by the sole of the foot-pocket portion 20.

The angle α may be 45° or more. In Figs. 1A-1C, the angle α is approximately 90°. In other words, the web portion 31 is attached to the foot-pocket portion 20 such that the plane of the web portion 31 is substantially perpendicular to the plane given by the bottom surface 24 of the foot-pocket portion 20. The web portion 31 is thus rotated by approximately 90° about the longitudinal axis A. However, it should be noted that angles other than 90° are equally possible. The angle is e.g. dependent on the intended use of the swim fin and should therefore be evaluated and tested in each specific case. Nevertheless, for the purpose of swimming in ground water, known as snorkeling, it has turned out that an angle of substantially 60° - 90° may be advantageous. A swim fin 10, as illustrated in Figs. 1A-1C, may e.g. be advantageously used when swimming in ground water. When utilizing a pair of swim fins with this configuration and orientation, it is possible for the swimmer to accomplish or execute generally lateral or horizontal leg movements. These lateral leg movements may be accomplished or executed in generally the same plane. For example, by performing breaststroke like leg kick movements, the legs may be moved in a generally horizontal plane, rather than in a vertical traditional kicking movement, during a complete aquatic kicking sequence. This movement sequence has certain advantages. For instance, this may aid the swimmer in propelling through the water, in particular in ground water or the like where there is little or no room for performing or executing a complete traditional upwards/downwards kicking sequence. Furthermore, it has turned out that a pair of such swim fins 10 allows for the swimmer to accomplish somewhat of a "gliding" effect, thus resulting in a smooth propulsion performance. This in turn may give the swimmer better control and smoother performance. Also, this may effectively aid the swimmer in propelling through the water. The swimmer may then also efficiently utilize his/her energy when swimming.

Furthermore, the swimmer normally wishes to have a comfortable and stable swimming position when swimming near the water surface, commonly known as snorkeling. When snorkeling in ground water the water may be rapid-flowing. Under such conditions it has turned out that it may be advantageous to utilize a pair of swim fins 10 and performing a breaststroke like leg kicking movement sequence. This way, it is generally easy for the swimmer to find a comfortable and stable swimming position without making use of excessive energy for e.g. compensating for the rapid-flowing water and/or for obtaining sufficient propulsion force along an intended travel path. Moreover, as appears from Fig. IB, the configuration and orientation of the swim fin 10 is such that, when the swimmer is swimming near the surface of the water, the fin portion 30 may have a position where an imaginary rim member, denoted 41, is substantially parallel with the surface of the water. It is possible to keep the swim fins 10 below the surface of the water during a complete lateral breaststroke like kicking sequence. Since no or at least only a few fluttering movements will then occur above the water surface, no or little excessive power is wasted. This may also help the swimmer to keep his/her buttocks substantially at the water surface. This in turn may allow for good floating capability of the body of the swimmer, which is normally desirable e.g. when snorkeling. With a pair of swim fins 10 it is also possible to aid the swimmer to obtain sufficient propulsion force along an intended travel path, because there is normally sufficient room for complete lateral leg kicking movements . This is true even in ground water where there may be a short distance between the water surface and the sea bottom. Accordingly, it is possible to effectively aid the swimmer in propelling through the water without wasting energy.

Moreover, in ground water it is generally easier to utilize a pair of swim fins 10 and moving the legs in a generally horizontal plane as compared to performing a traditional upwards and downwards fluttering movement with conventional swim fins. In addition, when swimming in ground water where there is a relatively short distance between e.g. coral reefs and the water surface the swimmer may run the risk of injuring himself/herself against the reefs when fluttering with the legs during the kicking.

This is especially true when the sea runs high and/or when the waves may lift the swimmer up and down. However, by utilizing the swim fins 10 and performing generally lateral leg movements, in contrast to traditional upwards/downwards leg movements, it has turned out that this injury risk may be reduced.

As is at least partially illustrated in Fig. IA, another advantage of the swim fin 10 in Figs 1A-1C is that the configuration and orientation of the swim fin is such that a pair of such swim fins enables the swimmer to walk e.g. on land or on a sea bottom. This is because the web portion 31 may be made of a relatively soft and flexible material. This allows the web portion 31 to at least partially fold itself along a folding line along the surface when a swimmer is walking. Furthermore, the configuration and orientation of a pair of swim fins 10 is such that it may enable the swimmer to keep the balance when walking. Thus, even if the fin portion 31 would be made of a comparatively more rigid material, the swimmer may still be able to walk on a relatively plain surface with a pair of swim fins 10, for example, by performing small lifted steps.

The web portion 31 may comprise two rim members, as at 41 and 42, wherein the web portion 31 is positioned there between. The rim members 41, 42 may e.g. be made of a more rigid material, compared to the web portion 31, in order to support the web portion 31. The first rim member 41 may be attached to the bottom surface 24 of the foot- pocket portion 20 whereas the second rim member 42 may be attached to the upper surface 25 of the foot-pocket portion 20. In order to enable the swimmer to walk on land or on a generally plain surface with swim fins 10 it may be advantageous to attach the first rim member 41 substantially at the front end 27 of the foot-pocket portion 20. Figs. 2A-2B disclose another embodiment of the swim fin 10. Features or components corresponding to those of the embodiment of Figs. 1A-1C are denoted by the same reference numerals. The fin portion 30 of the swim fin 10 comprises at least four web portions 31, 32, 33 and 34, respectively. The web portions 31, 32, 33, 34 are attached to the foot-pocket portion 20. In this regard, it should be noted that it may be advantageous to provide a swim fin 10, where the web portions 31, 32, 33, 34 are attached to the foot-pocket portion 20 substantially at the front end 27 of the foot-pocket portion 20. Furthermore, the web portions 31, 32, 33, 34 are configured to extend out forwardly in the longitudinal direction from the front end 27 of the foot-pocket portion 20, thereby serving as an extension of the foot-pocket portion 20. As is illustrated in Figs. 2A-2B, the web portions 31, 32, 33, 34 are also configured to cross each other in a line extending in the longitudinal direction.

As is illustrated in the figures, the configuration and orientation of the swim fin 10 is such that the bottom surface 24 and the web portions 31, 32, 33, and 34 are arranged along a joint axis A, which is given by the line extending in the longitudinal direction. The plane of the bottom surface 24, i.e. the sole of the foot-pocket portion 20, and the plane of the first web portion 31 may be arranged by an angle α in relation to one another. In the embodiment shown in Figs. 2A-2B this angle α may be approximately 45°. Furthermore, the different planes of the different web portions 31, 32, 33, and 34, respectively, may be arranged to one another by an angle β in relation to one another. In the embodiment shown in Figs. 2A-2B, the angle β is approximately 90°. Thus, each of the web portions 31, 32, 33, and 34 may be positioned at substantially 90° in relation to each other and cross each other along the joint axis. Consequently, this configuration and orientation of the web portions 31, 32, 33, 34 forms an "X"-like cross-section of the fin portion 30, as illustrated in Fig. 2B.

Regarding the dimensions of the four web portions 31, 32, 33 and 34, these web portions may e.g. have corresponding dimensions as the web portion 31 described in connection with the embodiment shown in Figs. lA-lC. Therefore, dimensions corresponding to those of the embodiment of Figs. 1A-1C are denoted by the same references in Figs. 2A and 2B. In this regard, it is however to be noted that the fin portion 30 may take a variety of alternative structural configurations other than that of Figs. 2A-2B.

The web portions 31, 32, 33 and 34 may be made of a relatively soft and flexible material. For example, the web portions may be made of a composition of natural rubber and plastic, e.g. Thermoplastic Elastomers (TPE) . The proportion between natural rubber and plastic, respectively, in the composition may be chosen e.g. in dependence of the desired flexibility characteristics of the fin portion 30. Furthermore, the proportion between natural rubber and plastic may vary at different sections of the fin portion 30, so as to obtain different degrees of softness and/or flexibility at different sections of the fin portion. Yet further, the composition may comprise different types of rubber and plastic, respectively. Optionally, silicon may also be included into the composition. It should however be emphasized that the material selection, softness and/or flexibility of the web portions is e.g. dependent on the intended use of the swim fin 10 and the specific needs of the swimmer. Thus, these considerations should be tested and evaluated in each specific case.

Additionally, the web portions 31, 32, 33, and 34 may comprise a respective rim member 43, 44, 45 and 46. The rim member 43 of the first web portion 31 and the rim member 44 of the second web portion 32 may be attached to the bottom surface 24 of the foot-pocket portion 20.

Furthermore, the rim member 45 of the third web portion 33 and the rim member 46 of the fourth web portion 34 may be attached to an upper surface 25 of the foot-pocket portion 20.

This embodiment of the invention has certain advantages. Similar to the embodiment described in connection with Figs. 1A-1C, this swim fin 10 may allow for the swimmer to accomplish or execute generally lateral leg movements in substantially the same plane, for example, by performing or executing breaststroke like leg kicking movements. Thus, the legs may be moved in a generally horizontal plane during a complete aquatic kicking sequence. This implies that this swim fin may obtain generally similar effects as the swim fin according to the embodiment described with reference to Figs. lA-lC. Accordingly, the swim fin 10 according to this embodiment of the invention may also be used when swimming in e.g. ground water.

In addition, the swim fin 10 in Figs. 2A-2B may enable the swimmer to perform or execute aquatic leg movements in more than one plane. For example, when utilizing a pair of swim fins with the configuration and orientation shown in Figs. 2A-2B it is possible for the swimmer to perform a traditional upwards and downwards fluttering kicking sequence (e.g. in a vertical plane) as well as a breast stroke like kicking sequence where the legs are moved laterally (e.g. in a horizontal plane) . Since the legs of the swimmer may be moved in various different directions and in various different planes, the swimmer may experience a better comfort. Furthermore, it is possible to obtain an effective propulsion force without making use of excessive power. For example, the swimmer may perform a traditional flutter-like kicking sequence when diving. However, when the swimmer is swimming in ground water or in narrow passages, where a traditional kicking sequence may be inappropriate, the swimmer may easily shift to a breaststroke like leg kicking sequence. This way the swimmer will be able to use his/her energy efficiently for obtaining good propulsion force along the intended travel path. Since the swimmer may consequently avoid using excessive energy, a reduction of stresses on the foot or ankle area of the swimmer may also be obtained. A further advantage is that, when turning under water, e.g. in a diving position, the swimmer may perform a kicking sequence in any direction, thereby enabling the swimmer to accomplish turns with less possible effort and twist of his/her body.

To sum up, the present invention may involve various advantages. For example, it may enable a swimmer to utilize alternative leg kicking movement patterns. This in turn may aid the swimmer to effectively propel through water. Furthermore, since various muscles may be used in dependence of the used leg kicking movement pattern the swimmer may also reduce the stress on certain muscles e.g. by varying between different leg kicking movement patterns. The present invention may also aid the swimmer in obtaining more efficiency when swimming.

The present invention has been described hereinabove with reference to specific embodiments. However, other embodiments than those described are equally possible within the scope of the invention. For example, the swim fin may be manufactured such that the foot-pocket portion is integrated with the fin portion, thereby forming a swim fin in the form of a single piece. Furthermore, the material selection of the swim fin may be chosen in dependence of the intended use of the swim fins and/or in dependence of the specific needs of a swimmer. Furthermore, the size, thickness and rigidity of the fin portion may vary. Also the shape of the web portion (s) may take a plurality of different forms. For example, the web portion may additionally comprise one or more ridges on its surface. The different features and components of the invention may be combined in other combinations than those described hereinabove. The scope of the invention is only limited by the appended patent claims .

Claims

1. A swim fin (10) comprising: a foot-pocket portion (20) comprising a bottom surface (24) and a front end (27) intended for receiving a toe portion of a foot; and a fin portion (30) comprising at least one web portion (31) attached to the foot-pocket portion (20) and configured to extend out forwardly in a longitudinal direction from the front end (27) of the foot-pocket portion (20) ; wherein a plane of the bottom surface (24) and a plane of the at least one web portion (31) are configured to cross each other in a line extending in the longitudinal direction.

2. A swim fin according to claim 1, wherein the at least one web portion (31) is attached to the foot- pocket portion (20) at the front end (27) of the foot- pocket portion (20) .

3. A swim fin according to claim 1 or 2, wherein the bottom surface (24) and the at least one web portion (31) are arranged along a joint axis given by the line extending in the longitudinal direction, and wherein the plane of the bottom surface (24) and the plane of the at least one web portion (31) are arranged to one another by an angle α in relation to one another.

4. A swim fin according to claim 3, wherein the angle α is approximately 45° or more.

5. A swim fin according to claim 4, wherein the angle α is substantially 90°.

6. A swim fin according to any of the claims 1-5, wherein said web portion (31) is made of a composition of natural rubber and plastic.

7. A swim fin according to any of the claims 1-5, wherein said web portion (31) is made of a Thermoplastic

Elastomer (TPE) .

8. A swim fin according to any of the preceding a claims, wherein the web portion (31) comprises first and second rim members (41, 42) and said web portion (31) is positioned in between said first and second rim members (32,33), wherein the first rim member (41) is attached to the bottom surface (24) of the foot-pocket portion (20) and the second rim member (42) is attached to an upper surface (25) of the foot-pocket portion (20) .

9. A swim fin according to claim 1 or 2, wherein the fin portion (30) comprises four web portions (31, 32, 33, 34), and wherein the bottom surface (24) and the web portions (31, 32, 33, 34) are arranged along a joint axis given by the line extending in the longitudinal direction, wherein the plane of the bottom surface (24) and the plane of a first web portion (31) of said four web portions (31, 32, 33, 34) are arranged to one another by an angle α in relation to one another, and wherein different planes of the different web portions (31, 32, 33, 34) are arranged to one another by an angle β in relation to one another.

10. A swim fin according to claim 9, wherein the angle α is substantially 45° and the angle β is substantially 90°.

11. A swim fin according to claim 9 or 10, wherein said web portion (31) is made of a composition of natural rubber and plastic.

12. A swim fin according to claims 9 or 10, wherein said web portion (31) is made of a Thermoplastic Elastomer (TPE) .

13. A swim fin according to any of the claims 9-12, wherein the each of the web portions (31, 32, 33, 34) comprises a respective rim member (43, 44, 45, 46); wherein the rim member (43) of the first web portion (31) and the rim member (44) of the second web portion (32) are attached to the bottom surface (24) of the foot-pocket portion (20) ; and the rim member (45) of the third web portion (33) and the rim member (46) of the fourth web portion (34) are attached to an upper surface (25) of the foot-pocket portion (20) .

14. A swim fin according to any of the preceding claims, wherein the foot-pocket portion (20) is configured to receive and at least partly surround a portion of a foot or the entire foot or receive and at least partly surround the foot as well as at least a portion of a lower leg.

15. A swim fin according claim 14, wherein a body (22) of said foot-pocket portion (20) is made of a composition of natural rubber and plastic.

16. A swim fin according to claim 14, wherein a body (22) of said foot-pocket portion (20) is made of a Thermoplastic Elastomer (TPE) .