Abstract:
A modular kayak including several main parts which are designed and manufactured so that their external form grants the modular kayak superior kayaking performance and enables their assembly into a single compact package, which can fit into the trunk of a regular family car and be easily carried by hand, over the shoulder, or on the back.

Description:
FIELD AND BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to kayaks and, in particular to modular kayaks. 
         [0002]    Kayaks and other small boats that can be assembled from separate sections are well known it the art. 
         [0003]    A foldable kayak is described in U.S. Pat. No. 4,057,865 of Trautwein, filed on Jun. 30, 1976. Trautwein taught a rigid bottom foldable on a central transverse hinge that has a removable tubular skeleton frame at each end supporting the skin. A pneumatic tubular member carried by the bottom sections serves to expand and tightly support the skin in use, thereby retaining the frame in assembled relation to the bottom  FIG. 1   a  is a side view of the kayak  400  according to Trautwein.  FIG. 1   b  is a section taken on line a-a of  FIG. 1   a . The illustration shows a tube  1  that needs to be inflated prior to use of the kayak and be deflated prior to folding the kayak. 
         [0004]    Another foldable boat with light weight hull construction system is described in U.S. Pat. No. 6,615,762 of Scott, filed on Aug. 23, 2001. Scott taught a boat of simple ultra light construction with few numbers of parts that can be easily assembled without tools, and when disassembled provides a compact lightweight package suitable for long range or rough terrain portage or back-packing. A plastic coated nylon waterproof cover or like skin can be conveniently slid onto, and off of the assembled hull and quickly fastened in place to provide waterproofing for the hull. 
         [0005]      FIG. 2  is a perspective view of the monocoque kayak  500  hull according to Scott without the waterproof cover taken from the rear and above. 
         [0006]    A breakdown sit-on and sit-in plastic paddleboat is described in Australian patent application No. AU 2004100379 A4 of Stattery filed on May 20, 2004. Stattery taught a breakdown kayak that has multiple hollow-form sections that can be coupled together in a detachable manner. 
         [0007]      FIG. 3   a  is a perspective illustration of a top view of a prior art rotationally molded, hollow-form, sit-in, one person, marine kayak  300 , having three-sections, the stem section  301 , the center section  302 , and the bow section  303 , according to Stattery. 
         [0008]      FIG. 3   b  is a perspective illustration of a prior art joint  310  between the center section  302  and the stem section  301  of the marine kayak  300  of  FIG. 3   a  after the sections have been separated. 
         [0009]    In spite of years of experience in development of kayaks and additional small folding and collapsing vessels, there is still thus a widely recognized need for, and it would be highly advantageous to have a folding kayak that can be folded or disassembled and reassembled quickly and easily for use, without any need for tools or inflation, that can by carried easily by hand or on the back, while maintaining the performance &amp; strength of the one piece kayaks, and especially for a kayak that can easily be stored in the trunk of a small family car. 
       SUMMARY OF THE INVENTION 
       [0010]    Small boating vessels have been known from the dawn of time. One of the most popular vessels is the kayak, an Eskimo canoe made of a frame of bones covered with skins with an opening in the center enabling the kayaker to enter the kayak and sit inside it. 
         [0011]    The kayak is propelled by a double-bladed paddle. The kayak originally served as a hunting vessel, with the kayaker/hunter equipped with a harpoon. 
         [0012]    Today kayaks are considered a recreational and/or sport vehicle, in various models, usually suitable for one or two kayakers, suitable for boating in rivers, lakes, seas, oceans and whitewater models. 
         [0013]    Kayaks are commonly made of Fiberglass, fiberglass with foam core or from a verity of plastics. There are presently two predominate types of kayaks, the first is the sit-in kayak. In this kayak, the kayaker sits inside the kayak casing, and there is a risk of incoming water sinking the kayak, therefore, in many kayaks, there is a sheet sealing the gap between the kayaker&#39;s body and the casing. 
         [0014]    The second type is the sit-on kayak. In this kayak, the kayaker sits on the kayak, even if there is an indentation in the kayak that can serve as a seat, and draining holes while the kayak is waterproof. The main advantage of this kayak is that there is no place for water to accumulate, thus avoiding the risk of sinking. Its main disadvantage is the usually loose seating of the kayaker on the kayak, if he is not strapped in, resulting in a rather high center of gravity. 
         [0015]    As used herein the specification and in the claims section that follows, the term “kayak” and the like refer to a boating vessel that is substantially moved independently by means of at least one bladed paddle, when the kayaker (or kayakers) is inside or upon it, seated, standing, or in any other position, has a bow (the front end), and a stem (the back end). 
         [0016]    This term also includes vessels known to boaters as: Kayak, Sit-On-Top WaveSki, Dinghy, WaterCraft, and Canoe. 
         [0017]    Typical lengths of kayaks are within the range of 2 to 5 meters, weighing between 8 to 50 kilograms, with the typical dimensions of a wave kayak are approximately 3 meters long, 65 cm wide, and 30 cm high. 
         [0018]    The present invention relates to a modular kayak composed of several main parts, for example two, three, or four main parts. The kayak can be in different configurations suited for specific situations such as: 
         [0019]    a. A unified configuration for storage and carrying, as a single compact package that is efficient in space consumption and has additional qualities that will be described later. 
         [0020]    b. A dismantled configuration, suitable for carrying and storing each part separately. 
         [0021]    c. A unified configuration for kayaking, as a kayaking vessel. 
         [0022]    These configurations determine the forms of the main parts, which are suited to conform to the other parts in structure and external form, so that the form of one part conforms to the form of a second part that is in contact with in kayaking configuration, and also conforms to a third part that is not in contact with in kayaking configuration however is in contact with in unified storage configuration. 
         [0023]    The present invention doesn&#39;t affect the kayaking performance of the kayak, yet greatly improves the transportation, carrying and storage of kayaks, for example, a modular kayak according to the present invention can fit into and be stored in the trunk of a family car, with typical dimensions of approximately 100×65×40 centimeters, with an opening width of 45 centimeters, or for carrying on one&#39;s back in a package whose dimensions are no larger than approximately 130×65×40 centimeters. 
         [0024]    The structure of the kayak according to the present invention is that of a thin shell according to the known principles of constructing aircrafts and boating vessels, a structure known as “hard shell” with structural qualities of strength and elasticity that meet all of the kayak&#39;s structural requirements, without any need for added reinforcements such as partitions and supports. 
         [0025]    The material or materials composing the hard shell can be any material suitable for use in marine sport products providing the necessary structural qualities, such as metals or plastic materials for inexpensive kayaks, or composite materials optionally with foam cored for higher quality kayaks, of light weight and high performance. 
         [0026]    The complete kayak includes two, three, or more main structural parts. For example, in a kayak including three main structural parts, according to the present invention, the bow section (the front unit), of the modular kayak, is connected on one end of the central section, and the stem section, which serves as the back end of the modular kayak, is connected on the other end of the central unit. 
         [0027]    Each of the main structural parts has a geometrical form that conforms to the part to which it is connected to obtain the kayaking configuration, this geometrical form also conforms to one or more main structural parts for the unified package configuration, in a manner that enables assembling all of the kayak&#39;s parts into a compact and efficient package that is suitable for carrying by hand, on one&#39;s back or shoulder, and for storage in a narrow place such as the trunk of a small family vehicle. 
         [0028]    The external forms that are fitted to the main structural parts serve as connectors and are of suitable dimensions to handle the forces and moments exerted on the kayak, and are designed to add structural integrity to the kayak. Latches or other means of attachment can be added to these forms to obtain safer locking of the parts in place. External straps can also be added to tighten the package when the kayak is in package configuration, as well as straps for carrying the package. The straps can be put in a pouch or in a storage compartment on the kayak when in the water, enabling the kayaker to be free of any transportation device. 
         [0029]    Each of the main structural parts can be waterproof and buoyant, or the structure of the kayak can alternatively include gaskets disposed between the main structural parts with interconnecting lips known in the art as flanges for the option of a Sit-In-Kayak. The main structural parts can include openings for draining water that can be sealed with plugs. 
         [0030]    When the kayak is a sit-on modular kayak, the design of its top part can include indentations for comfortable seating, including indentations for the legs. 
         [0031]    When the kayak is a sit-in modular kayak, there is a cockpit, an area where the kayaker sits while in the modular kayak. The number of seating apparatuses conforms to the number of kayakers for which the kayak is designated. A modular configuration, which enables extending the kayak and adapting it to a larger number of kayakers, by adding one or more additional central unit, is also possible. 
         [0032]    The guiding principle in selecting the external form of the main structural parts of the kayak is designing optimal forms to enable the external form of the hull, the bottom side of the modular kayak, is suitable for achieving kayaking performance that meets the kayak&#39;s designation when in kayaking configuration while the external form of the top of each of the main structural parts also conforms to an optimal package configuration, enabling assembly of the main structural part into a stable package with external dimensions that are suitable for storage in small places, or places with a certain limited internal space and opening, such as the internal space and opening of the trunk of a certain make of family car, without detracting from the kayak&#39;s performance in water. 
         [0033]    According to the above guiding principle, the design of the modular kayak, which can be achieved by means of trial and error, includes the following design instructions: 
         [0034]    The hull is designed according to the kayaking performance required of the modular kayak, as in the hull design of a kayak that is built in one piece, including efficient hydrodynamic design as is practiced in kayak design. 
         [0035]    Maintaining a suitable volume to achieve the necessary buoyancy qualities. 
         [0036]    Giving the deck part an external form, namely the outer surface of the deck of each of the main structural parts, which conforms to the forms of the outer surfaces of the other parts that are adjacent to it when assembled in package configuration without compromising the performance of the kayak. The forms of all of the main parts enable assembly as one compact package which makes efficient use of volume and has structural qualities that prevent linear and rotational movement of the main structural parts as much as possible, so that they are separated from each other only when pulled away from each other along imaginary axis Z, in an orthogonal coordinate system fixed to the center section of the modular kayak, with Y axis going forward in the direction of the bow on the symmetry plane of the modular kayak, X axis going right perpendicular to Y axis and Z axis going upward perpendicular to the plane generated by X and Y axes. 
         [0037]    No dimension of any single part of the modular kayak will exceed a predefined maximal value, such as 100 centimeters. 
         [0038]    The connection apparatus of the modular kayak&#39;s parts will not be in any place where they can come into contact with the kayaker&#39;s body, in order to prevent possible injury (such as pinching). 
         [0039]    Aesthetic External Design. 
         [0040]    Granting strength and elasticity to the structure of the modular kayak for kayaking, carrying, and storage configurations. 
         [0041]    The present invention has the following main advantages in comparison to all the foldable and collapsible kayaks of prior art: 
         [0042]    The kayak, depending on the type and the used material weighs like a one piece structure, is suitable to be carried by an adult for long distances under difficult conditions. 
         [0043]    Assembly and dismantling of the kayak are very simple, do not require any expertise or use of any tools, and are performed in short time intervals, which can be less than two minutes. 
         [0044]    The modular kayak has superior strength and performance without competition. 
         [0045]    The kayak is safer and has none of the special restrictions that usually apply to foldable kayaks. 
         [0046]    The kayak as a hard shell doesn&#39;t have the disadvantage of increased hull drag due to soft skin collapsible kayaks. 
         [0047]    The kayak has a more aesthetically pleasing design. 
         [0048]    Carrying and storage of the kayak are optimal: 
         [0049]    Its parts can be assembled into an efficient, conformant, and compact package. 
         [0050]    The kayak can be packed in a simple apparatus that enables carrying on the back or over the shoulder, or in other ways. 
         [0051]    All of the parts of the kayak can fit into the trunk of any family car without any need for special apparatus or trailers. 
         [0052]    Convenient carrying from the vehicle to the kayaking site, and from the site back to the vehicle. 
         [0053]    Enables carrying and moving in small spaces such as elevators, means of public transportation, and when riding a bicycle. 
         [0054]    Convenient and easy to carry as baggage when traveling abroad. 
         [0055]    Efficient storage at home or in a storage space. 
         [0056]    According to the teachings of the present invention there is provided a modular kayak having at least two possible configurations, one a unified carrying and storage compact package configuration, and the other a unified kayaking configuration, the modular kayak including: (a) a bow section having a hull surface and a deck surface; (b) a center section having a hull surface and a deck surface, wherein the center section defines a three-dimensional XYZ Cartesian coordinate system, wherein X axis goes forward, Z axis goes upward, and Y axis goes to the right of the center section, with each axis perpendicular to the plane created by the other two axes; and (c) a stern section having a hull surface and a deck surface. 
         [0057]    According to still further features in the described preferred embodiments the bow section has a partition surface, the center section has a first partition surface, and a second partition surface, and the stem section has a partition surface. 
         [0058]    According to still further features in the described preferred embodiments when the modular kayak is in unified kayaking configuration, the bow section hull surface, the center section hull surface, and the stem section hull surface define a continuous spatial geometrical surface, as in a conventional kayak, which is suitable for granting the modular kayak with superior kayaking performance. 
         [0059]    According to still further features in the described preferred embodiments each of the stem section, the center section, and the bow section, is waterproof and buoyant. 
         [0060]    According to still further features in the described preferred embodiments the center section first partition surface has 3D partition&#39;s conformal surface, wherein the center section second partition surface has 3D partition&#39;s conformal surface, wherein the bow section partition surface has 3D partition&#39;s conformal surface, and, wherein the stem section partition surface has 3D partition&#39;s conformal surface. 
         [0061]    According to still further features in the described preferred embodiments the bow section has a maximum length dimension of no more that one meter, wherein the center section has a maximum length dimension of no more than one meter, and wherein the stem section has a maximum length dimension of no more than one meter. 
         [0062]    According to still further features in the described preferred embodiments when the modular kayak is in unified kayaking configuration, the bow section hull surface, the center section hull surface, and the stern section hull surface define a continuous spatial geometrical surface, as in a conventional kayak, which is suitable for granting the modular kayak with superior kayaking performance, wherein each of the stem section, the center section, and the bow section, is waterproof and buoyant, wherein the center section first partition surface has 3D partition&#39;s conformal surface, wherein the center section second partition surface has 3D partition&#39;s conformal surface, wherein the bow section partition surface has 3D partition&#39;s conformal surface, and, wherein the stem section partition surface has 3D partition&#39;s conformal surface, wherein the bow section has a maximum length dimension of no more that one meter, wherein the center section has a maximum length dimension of no more than one meter, and wherein the stem section has a maximum length dimension of no more than one meter. 
         [0063]    According to still further features in the described preferred embodiments the bow section&#39;s deck surface has a 3D deck conformant surface, wherein the center section deck surface has a 3D deck conformant surface, and wherein the stem surface has a 3D deck conformant surface. 
         [0064]    According to still further features in the described preferred embodiments the bow section has a maximum height dimension and a maximum width dimension, wherein the center section has a maximum height dimension and a maximum width dimension, and wherein the stem section has a maximum height dimension and a maximum width dimension. 
         [0065]    According to still further features in the described preferred embodiments the modular kayak has a total maximum dimension, wherein the total maximum dimension is at most 0.9 multiplied by the sum (of the bow section maximum height dimension plus the center section maximum height dimension plus the stem section maximum height dimension). 
         [0066]    According to still further features in the described preferred embodiments the modular kayak has a total maximum dimension, wherein the total maximum dimension is at most 0.7 multiplied by the sum (of the bow section maximum height dimension plus the center section maximum height dimension plus the stem section maximum height dimension). 
         [0067]    According to still further features in the described preferred embodiments the modular kayak further including: (d) fastening device; and (e) carrying straps. 
         [0068]    According to still further features in the described preferred embodiments the modular kayak further including: (d) fastening device; and (e) carrying straps; wherein the bow section&#39;s deck surface has a 3D deck conformant surface, wherein the center section deck surface has a 3D deck conformant surface, and wherein the stern surface has a 3D deck conformant surface, wherein the bow section has a maximum height dimension and a maximum width dimension, wherein the center section has a maximum height dimension and a maximum width dimension, and wherein the stem section has a maximum height dimension and a maximum width dimension, and wherein the modular kayak has a total maximum dimension, wherein the total maximum dimension is at most 0.9 multiplied by the sum (of the bow section maximum height dimension plus the center section maximum height dimension plus the stem section maximum height dimension). 
         [0069]    According to the present invention there is provided a method for enabling a kayaker to use a modular kayak, the method including the steps of: (a) providing the kayaker with a modular kayak, the modular kayak including: (i) a bow section having a hull surface, a deck surface, and a partition surface; (ii) a center section having a hull surface, a deck surface, a first partition surface, and a second partition surface, wherein the center section defines a three-dimensional XYZ Cartesian coordinate system, wherein X axis goes forward, Z axis goes upward, and Y axis goes to the right of the center section, with each axis perpendicular to the plane created by the other two axes; (iii) a stem section having a hull surface, a deck surface, and a partition surface; (iv) fastening device; and (v) carrying straps; wherein when the modular kayak is in unified kayaking configuration, the bow section hull surface, the center section hull surface, and the stern section hull surface define a continuous spatial geometrical surface, as in a conventional kayak, which is suitable for granting the modular kayak with superior kayaking performance, wherein the center section first partition surface has 3D partition&#39;s conformal surface, wherein the center section second partition surface has 3D partition&#39;s conformal surface, wherein the bow section partition surface has 3D partition&#39;s conformal surface, and, wherein the stem section partition surface has 3D partition&#39;s conformal surface, wherein the bow section has a maximum height dimension and a maximum width dimension, wherein the center section has a maximum height dimension and a maximum width dimension, and wherein the stem section has a maximum height dimension and a maximum width dimension, and wherein the modular kayak has a total maximum dimension, wherein the total maximum dimension is at most 0.9 multiplied by the sum (of the bow section maximum height dimension plus the center section maximum height dimension plus the stem section maximum height dimension); (b) packing the bow section, the center section, and the stem section; (iv) fastening the modular kayak with the fastening device; and (v) putting the modular kayak into a car. 
         [0070]    According to the present invention the method further includes the steps of: (vi) removing the modular kayak from the car; (vii) carrying the modular kayak on the back; (viii) unfastening the fastening device; (viii) connecting the stem section to the center section; and (ix) connecting the bow section to the center section. 
         [0071]    According to the present invention the method further includes the steps of: (x) putting the modular kayak on the water; and (xi) kayaking. 
         [0072]    According to a preferred embodiment of to the present invention the packing includes the steps of: (i) placing the center section on the ground, with the center section&#39;s hull portion facing down; (ii) placing the bow section upon the center section, with the bow section&#39;s hull portion facing up; and (iii) placing the stem section upon the bow section, with the stem section&#39;s hull portion facing up. 
         [0073]    According to another preferred embodiment of to the present invention the packing includes the steps of: (i) placing the stem section on the ground, with the stem section&#39;s hull portion facing up; (ii) placing the bow section upon the stem section, with the bow section&#39;s hull portion facing up; and (iii) placing the center section upon the bow section, with the center section&#39;s hull portion facing down. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0074]    The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: 
           [0075]      FIG. 1  a is a side view of a prior art kayak. 
           [0076]      FIG. 1   b  is a section of the prior art kayak of  FIG. 1   a.    
           [0077]      FIG. 2  is a perspective view of another prior art kayak. 
           [0078]      FIG. 3   a  is a perspective top view from of a prior art sit-in, one person, marine kayak, with three sections. 
           [0079]      FIG. 3   b  is a perspective view of a joint between the center section and the stern section of the prior art marine kayak of  FIG. 3   a , after the sections have been separated. 
           [0080]      FIG. 4   a  is a schematic perspective illustration of a preferred embodiment of a modular kayak of the present invention composed of three main parts. 
           [0081]      FIG. 4   b  is a schematic perspective illustration of the modular kayak of  FIG. 4   a  with its three main parts separated from each other, according to the present invention. 
           [0082]      FIG. 5   a  is a schematic perspective illustration of another preferred embodiment of a modular kayak of the present invention composed of three main parts. 
           [0083]      FIG. 5   b  is a schematic perspective illustration of the modular kayak of  FIG. 5   a  dismantled into three parts, in package configuration, according to the present invention. 
           [0084]      FIG. 6   a  is a schematic perspective illustration of a side view of a preferred embodiment of the modular kayak of the present invention of  FIG. 4   a.    
           [0085]      FIG. 6   b  is a schematic illustration of a top view of a preferred embodiment of the modular kayak of the present invention of  FIG. 4   a.    
           [0086]      FIG. 6   c  is a schematic illustration of a bottom view of a preferred embodiment of the modular kayak of the present invention of  FIG. 4   a.    
           [0087]      FIG. 6   d  is a schematic illustration of b-b section of a preferred embodiment of the modular kayak of the present invention of  FIG. 6   b.    
           [0088]      FIG. 6   e  is a schematic illustration of a preferred embodiment of the modular kayak of the present invention of  FIG. 4   a  in unified package configuration for storage and carrying, marked with six lateral section lines. 
           [0089]      FIG. 6   f  is a schematic illustration of the lateral sections of  FIG. 6   e.    
           [0090]      FIG. 7   a  is a schematic perspective illustration of the modular kayak of the present invention of  FIG. 4   a  dismantled into three parts in package configuration. 
           [0091]      FIG. 7   b  is a schematic perspective illustration of an additional view of the modular kayak of  FIG. 4   a  dismantled into three parts in package configuration according to the present invention. 
           [0092]      FIG. 7   c  is a schematic illustration of a view of one of the bases of the central part of the modular kayak of  FIG. 7   a  dismantled into three parts in unified package configuration for storage and carrying, as a single compact package according to the present invention. 
           [0093]      FIG. 7   d  is a schematic cross section illustration of the modular kayak of  FIG. 7   c  along line a-a with the three main parts distanced from each other in separate parts configuration, suitable for separate carrying of each part according to the present invention. 
           [0094]      FIG. 7   e  is a schematic cross section illustration of the kayak of  FIG. 7   c  along line a-a in package configuration according to the present invention. 
           [0095]      FIG. 8   a  shows a kayaker pulling the kayak parts out of a car trunk according to the present invention. 
           [0096]      FIG. 8   b  shows a kayaker assembling the kayak parts into a unified package according to the present invention. 
           [0097]      FIG. 8   c  shows a kayaker carrying the modular kayak as a package using straps, over his shoulder according to the present invention. 
           [0098]      FIG. 8   d  shows a kayaker carrying a modular kayak as a package using straps, on his back according to the present invention. 
           [0099]      FIG. 9   a  is a schematic illustration of a side view of latch and hook, which can be used to fasten the main parts of the kayak to each other in a unified kayaking configuration, in closed position. 
           [0100]      FIG. 9   b  is a perspective schematic illustration of latch and hook, which can be used to fasten the main parts of the kayak to each other in a unified kayaking configuration, in closed position. 
           [0101]      FIG. 9   c  is a perspective schematic illustration of latch and hook, which can be used to fasten the main parts of the kayak to each other in a unified kayaking configuration, in open position. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0102]    The present invention is a modular kayak. 
         [0103]    The principles and operation of a modular kayak according to the present invention may be better understood with reference to the drawings and the accompanying description. 
         [0104]    Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. 
         [0105]    Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, dimensions, methods, and examples provided herein are illustrative only and are not intended to be limiting. 
         [0106]    The following list is a legend of the numbering of the application illustrations: 
         [0107]      300  kayak according to Stattery 
         [0108]      301  stem section (of Stattery&#39;s Kayak) 
         [0109]      302  center section (of Stattery&#39;s Kayak) 
         [0110]      303  bow section (of Stattery&#39;s Kayak) 
         [0111]      310  joint between the center section and the stem section (of Stattery&#39;s Kayak) 
         [0112]      400  kayak according to Trautwein 
         [0113]      500  kayak according to Scott 
         [0114]      1  tube (of Trautwein&#39;s Kayak) 
         [0115]      11   a  bow section&#39;s hull portion 
         [0116]      11   b  bow deck portion 
         [0117]      11   c  contact area 
         [0118]      12   a  center section&#39;s hull portion 
         [0119]      12   b  center section&#39;s deck portion 
         [0120]      12   c  contact area 
         [0121]      12   d  contact area 
         [0122]      13   a  stem section&#39;s hull portion 
         [0123]      13   b  stem section&#39;s deck portion 
         [0124]      13   c  contact area 
         [0125]      14   a  hook (for latching) 
         [0126]      14   b  latch 
         [0127]      15  seating surface 
         [0128]      16  drain holes 
         [0129]      17  shoulder of the bow deck portion 
         [0130]      18   a  fastening device 
         [0131]      18   b  (back) carrying strap 
         [0132]      18   c  (shoulder) carrying strap 
         [0133]      19  section of the contact line between the bow section and the center section 
         [0134]      20  section of the contact line between the center section and the stem section 
         [0135]      21  peripheral surface 
         [0136]      22  protrusion 
         [0137]      23  protrusion 
         [0138]      24  indentation 
         [0139]      120  kayaker 
         [0140]      130  trunk of a car 
         [0141]      100  modular kayak of the present invention 
         [0142]      101  bow section 
         [0143]      102  center section 
         [0144]      103  stern section 
         [0145]    Referring now to the drawings,  FIG. 1   a  is a side view of a prior art kayak. 
         [0146]      FIG. 1   b  is a section of the prior art kayak of  FIG. 1   a.    
         [0147]      FIG. 2  is a perspective view of the monocoque kayak  500  hull according to Scott without the waterproof cover taken from the rear and above. 
         [0148]      FIG. 3   a  is a perspective illustration of a top view of a prior art sit-in one-person marine kayak with three-sections. 
         [0149]      FIG. 3   b  is a perspective view of a prior art joint between the center section and the stern section of the marine kayak of  FIG. 3   a , after the sections have been separated. 
         [0150]      FIG. 4   a  is a schematic perspective illustration of a preferred embodiment of a modular kayak  100  of the present invention composed of three main parts, the bow section  101 , the center section  102 , and the stern section  103 . The coordinate system shown in the illustration defines axes fixed to center section  102 . X axis goes forward, Z axis goes upward, and Y axis goes right, with each axis perpendicular to the plane created by the other two axes. 
         [0151]      FIG. 4   b  is a schematic perspective illustration of the modular kayak  100 , when its three main parts are separated from each other. The illustration shows bow section&#39;s hull portion  11   a  and deck portion  11   b , center section&#39;s hull portion  12   a  and deck portion  12   b , and stern section&#39;s hull portion  13   a  and deck portion  13   b . Furthermore the illustration shows the areas of the modular kayak&#39;s main parts, which come into contact with each other when assembled to kayaking configuration. Area  11   c  of bow section  101  is suitable for contact with area  12   c  of center section  102 . Area  13   c  of stem section  103  is suitable for contact with area  12   d  of center section  102 . In addition, the illustration shows means for fastening the parts after connection, or releasing the sections, such as latch  14   b  and hook  14   a.    
         [0152]      FIG. 5   a  is a schematic perspective illustration of another preferred embodiment of a modular kayak  200  of the present invention composed of three main parts the bow section  201 , the center section  202 , and the stem section  203 . The illustration shows a coordinate system, similar to that which is shown in  FIG. 4   a.    
         [0153]      FIG. 5   b  is a schematic perspective illustration of modular kayak  200 , dismantled into three parts, which are assembled into package configuration. The bottom part of the package is stem section  203 , on which as shown in the illustration bow section  201  is placed upside-down, and over both center section  202  is also placed upside-down. 
         [0154]      FIG. 6   a  is a schematic illustration of a side view of a preferred embodiment of the modular kayak  100  of  FIG. 4   a.    
         [0155]      FIG. 6   b  is a schematic illustration of a top view of a preferred embodiment of the modular kayak  100 . The illustration shows seating surface  15 , which serves as the kayaker&#39;s seat. 
         [0156]      FIG. 6   c  is a schematic illustration of a bottom view of a preferred embodiment of the modular kayak  100 . The illustration shows several drain holes  16 . The illustration also shows that each of the modular kayak&#39;s main parts has a maximal width dimension, respectively marked as Y 101 , Y 102 , and Y 103 . 
         [0157]      FIG. 6   d  is a schematic illustration of a b-b section of  FIG. 6   b  of a preferred embodiment of the modular kayak  100 . This illustration shows the conformity of the modular kayak&#39;s main parts to each other in their joint contact areas, in kayaking configuration of the modular kayak. The illustration shows a section of contact line  19  between the bow section and the center section and a section of contact line  20  between the center section and the stern section. 
         [0158]      FIG. 6   e  is a schematic illustration of a preferred embodiment of the modular kayak  100  of  FIG. 4   a  in unified package configuration for storage and carrying, with the center section  102  on the bottom, the stem section  103  on top, and the bow section  101  in between, marked with six lateral section lines. 
         [0159]      FIG. 6   f  is a schematic illustration of the six lateral sections of  FIG. 6   e . This illustration shows the conformity of the modular kayak&#39;s main parts to each other in their joint contact areas in unified storage and carrying package configuration. The form of the deck surface of each of the modular kayak&#39;s main parts has qualities that are suitable for achieving a compact package, which consumes little space and prevents linear and rotational movement of these parts with regard to each other. The relevant sections in the illustration define the forms of the deck surfaces. The illustration shows that the form of the deck surface of one of the modular kayak&#39;s main parts need not be identical to the form of the deck surface of another main part to which it is adjacent in package configuration. Several contact point shared by both of the adjacent modular kayak&#39;s main parts are sufficient. 
         [0160]    As used herein the specification and in the claims section that follows, the term “3D deck conformant surface” and the like refer to a deck substantially having the necessary qualities to prevent rotational and linear movement between the modular kayak&#39;s main structural parts in the unified storage and carrying package configuration, and to achieve minimal packing size. 
         [0161]      FIG. 7   a  and  FIG. 7   b  are schematic perspective illustration of two views of the modular kayak  100  of  FIG. 4   a  dismantled into three parts in package configuration. The illustration shows how the modular kayak&#39;s main parts can be assembled together into a single compact package. Center section  102  serves as the base of the package, with the center section&#39;s deck portion  12   b  facing the bow&#39;s deck portion lib and the bow section&#39;s hull portion  11   a  facing the stern section&#39;s deck portion  13   b . Packing the modular kayak&#39;s main parts in package configuration can be performed in the following stages, starting from the kayaking configuration of the modular kayak, resting on the ground:
       a. Opening the latches  14   b  and separating the kayak&#39;s main parts from each other.   b. Lifting the bow section  101 , rotating it in the air by 180 degrees around an imaginary axis parallel to Y axis, and putting it in place upon the center section  102 .   c. Lifting the stern section  103 , rotating it in the air by 180 degrees around an imaginary axis parallel to Y axis, and putting it in place upon the bow section  101 .         
         [0165]    The forms of the modular kayak&#39;s main parts according to the present invention ensure that there will be rigidity regarding each part with regard to the adjacent part or parts on a plane parallel to X-Y plane. In  FIG. 7   b , the marking of the shoulders  17  of the bow deck portion  101  has been emboldened. A description of this is given later in the description of  FIG. 7   c.    
         [0166]      FIG. 7   c  is a schematic illustration of a view of one of the bases of the center section  102  of the modular kayak  100  dismantled into three parts in package configuration. The illustration shows the design, which prevents relative, linear, and rotational movement of the modular kayak&#39;s two main parts the bow section  101  and the center section  102  on a plane perpendicular to Z-axis. This is achieved by means of the shoulders  17  of the bow deck portion  101 . 
         [0167]      FIG. 7   d  is a schematic illustration of a cross section of the modular kayak of  FIG. 7   a  in separate parts configuration, suitable for carrying and storage of each part separately, namely separated from each other, each shown in a section of line a-a as shown in  FIG. 7   c.    
         [0168]    Each of the partition surfaces serving as a contact area between the modular kayak&#39;s main parts, when the modular kayak is in kayaking configuration, has a three dimensional form that ensures stiffness in linear or rotational movement between two of the modular kayak&#39;s adjacent main parts, other than the linear movement of separation along X axis. This quality is achieved by means of protrusions and indentations on the three-dimensional forms, as shown for example in stern section  103  which has a curved partition surface including a segment adjacent to the stern section&#39;s hull portion  13   a , which is connected to surface  23  which has a component in X direction connecting it to protrusion  22 . Center section  102  has a curved partition surface with an indentation  24 , which fits precisely to protrusion  22 . 
         [0169]    As used herein the specification and in the claims section that follows, the term “3D partition conformant surface” and the like refer to a partition substantially having the necessary qualities to prevent rotational and linear movement between the modular kayak&#39;s main structural parts in kayaking configuration. 
         [0170]    As shown in the illustration, each of the modular kayak&#39;s main parts has a maximal height dimension, respectively marked as  101   z , Z 102 , and Z 103 , and a maximal length dimension, respectively marked as X 101 , X 102 , and X 103 . 
         [0171]      FIG. 7   e  is a schematic illustration of a cross section of the modular kayak  100  of  FIG. 7   c  along line a-a in unified storage and carrying package configuration, as a single compact package. As shown in the illustration, the package that is created when the modular kayak is in unified storage and carrying package configuration, there is a general maximal length dimension marked as X 100  and a general maximal height dimension marked as Z 100 . 
         [0172]    Thanks to the structure of the modular kayak&#39;s main parts which are assembled together in package configuration, the general maximal height dimension of the entire package is smaller that the sum of the individual maximal height dimensions of each of the modular kayak&#39;s main parts, namely Z 100 &lt;(Z 101 +Z 102 +Z 103 ). Kayaks built according to the present invention have been proven to achieve at least Z 100 &lt;0.7×(Z 101 +Z 102 +Z 103 ). 
         [0173]    As used herein the specification and in the claims section that follows, the term “total maximum dimension” and the like refer to the substantially maximal height dimension of the modular kayak, when it is in unified storage and carrying package configuration. 
         [0174]      FIG. 8   a  shows a kayaker  20  removing the kayak&#39;s main parts center section  102  and stern section  103  from the trunk  30  of a car. 
         [0175]    The illustration shows one of the options for inserting and removing modular kayak  100  into and from the trunk of a car, in this case, each part separately. An additional possibility is inserting and removing modular kayak  100  in a unified package configuration. 
         [0176]      FIG. 8   b  shows a kayaker  20  assembling the modular kayak&#39;s main parts bow section  101 , center section  102 , and stem section  103  to unified storage and carrying package configuration. 
         [0177]      FIG. 8   c  shows the kayaker  20  carrying the modular kayak  100  in package configuration with carrying straps  18   c  over his shoulder. The modular kayak&#39;s main parts are fastened with fastening device  18   a.    
         [0178]      FIG. 8   d  shows the kayaker  20  carrying the kayak  100  as a package with carrying straps  18   b  on his back. The modular kayak&#39;s main parts are fastened with fastening device  18   a.    
         [0179]      FIG. 9   a ,  FIG. 9   b , and  FIG. 9   c , are schematic illustrations of a latch, which can be used to fasten the kayak&#39;s main parts to each other in kayaking configuration. Latch  14   b  latches onto hook (for latching)  14   a  when they are connected to the kayak&#39;s main parts on fasten them for unified kayaking configuration. 
         [0180]    Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.