embodiments of the present invention will now be described with reference to the accompanying drawings . the present invention relates to a propulsion apparatus to which an oscillating foil mechanism is applied to an ‘ l - shaped oar ’ and a boat that obtains propulsion force by using the same . the l - shaped oar means an oar having a ‘ loom that is bent in an l shape ’ in the whole outer appearance in a top plan view . this l - shaped oar may convert rider &# 39 ; s forward and backward arm movement that is inputted to one end of the oar into a left and right motion of the other end when setting the boat &# 39 ; s sailing direction forward . fig2 a is a schematic top plan view illustrating a human - powered propulsion apparatus and a geometry and mechanism of a human - powered boat using the same according to the present invention . a human - powered boat 100 , according to the present invention , has a structure in which two l - shaped propulsion apparatuses 35 are mounted bilaterally symmetric to each other with respect to a longitudinal axis 99 of a boat body 79 having a predetermined length and width and moving forward ( m ). in the present invention , a human - powered boat 100 may be a boat in a dictionary definition that is a small ship designed to be able to float while moving on water as well as a board concept including an inflatable float having various shapes in which a person rides thereon on water . in addition , it is preferable that the boat body 79 constituting the human - powered boat 100 of the present invention includes an inflatable float on at least one side of both sides thereof or the boat body is an inflatable float in itself but is not limited thereto . in detailed descriptions with respect to the position and configuration of the propulsion apparatus 35 , a first pivot 11 is positioned away by a predetermined distance outward from a longitudinal axis 99 of the boat body 79 , and the propulsion apparatus 35 oscillates about the first pivot 11 . here , a potion at which a handle crank 31 and an oscillating crank 32 , which serve as an oar &# 39 ; s loom in the propulsion apparatus 35 , meet approximately perpendicular to each other and then coupled to each other is fixed to the boat body 79 by the first pivot 11 . as illustrated in the drawings , the handle crank 31 has a predetermined length and is placed in a width direction of the boat body 79 so that an outer end 33 thereof is coupled to the first pivot 11 , and the oscillating crank 32 has a predetermined length and is placed in a longitudinal direction of the boat body 79 so that a front end thereof is coupled to the first pivot 11 . here , it is preferable that the handle crank 31 and the oscillating crank 32 are coupled to each other at an angle that is approximately perpendicular to each other , but the angle may be adjusted according to a position of the rider or a structure of the boat body 79 . in addition , a plate - shaped foil 12 having a length and height is coupled to a rear end 34 of the oscillating crank 32 in a longitudinal direction of the boat body 79 . when the rider seats behind the handle crank 31 and grips it by hand and then alternately move the handle crank 31 forward and backward , the foil 12 may oscillate in a left and right direction about the first pivot 11 to generate propulsion force . this operation may correspond to forward - facing rowing in which the rider faces an advancing direction of the boat body 79 and moves the boat . here , the propulsion apparatus 35 is illustrated in a state in which the oscillation is stopped at an angle at which propulsion resistance with respect to a flow of the water in a longitudinal direction of the boat body 79 is smallest and this state may be defined as an idle state in the present invention . to improve efficiency of the propulsion apparatus 35 according to the oscillating foil mechanism that is described above under the title of background , it is preferable that a second pivot 13 is added to a portion at which the oscillating crank 32 and the foil are coupled to each other . here , the second pivot 13 may allow the propulsion apparatus 35 to have a specific pitch in generating the propulsion force , like a propeller , and the foil 12 may complexly oscillate about the first pivot 11 and the second pivot 13 . in the present invention , when a maximal oscillation is performed having the same left and right angle with respect to the idle state of the oscillating crank 32 to generate the propulsion force , an area on which the foil 12 is swept on a virtual plane that is parallel to the water surface and cuts a center of the foil 12 may be defined as a maximum motion range 21 . in the drawing , the area is expressed on portions of the propulsion apparatus 35 , which are symmetrically opposed to each other , due to spatial restraint . fig2 b is a schematic front view of the human - powered boat 100 illustrated in fig2 a . fig2 b illustrates a left side of the boat body 79 . since the outer end 33 of the handle crank 31 is positioned in a higher portion of the boat body 79 , and the rear end 34 of the oscillating crank 32 is positioned in a lower portion of the boat body 79 , it is confirmed that a height difference h 1 is clearly generated between the outer end 33 and the rear end 34 . further , the rear end 34 of the oscillating crank 32 is positioned higher than the lowest portion of the boat body 79 . a reason in which a distance 6 from a first rotation axis 55 provided by the first pivot 11 to a second rotation axis 66 provided by the second pivot 13 is greater than a straight - line distance l 1 from the first rotation axis 55 to the rear end 34 of the oscillating crank 32 in a longitudinal direction of the boat body 79 is for representing the technical knowledge in which the propulsion efficiency of the oscillating foil is improved when the second pivot 13 ( or the second rotation axis 66 ) is positioned backward from a front portion of the foil 12 with somewhat space . furthermore , it is preferable that the foil 12 has a height greater than a length thereof to form a shape that is elongated downward on the whole . this shape may improve the propulsion efficiency by quickly performing a flapping motion of the foil 12 together with the second rotation axis 66 moved backward . the above - described human - powered boat and human - powered propulsion apparatus may have three functional limitations in operation thereof . first , since the oscillating crank 32 oscillates about only the first rotation axis 55 , it is impossible to tilt the oscillating crank 32 through the vertical movement of the rider &# 39 ; s arm during movement . thus , it is difficult to adjust a depth , to which the foil is submerged in the water , by the rider as if a general oar is used . second , since a range in which the oscillating crank moves without contacting the boat body 79 , is limited under a configuration that the first pivot 11 providing a center about which the propulsion apparatus oscillates is positioned on a side of the boat body 79 , it is difficult to allow the foil 12 to pass through the longitudinal axis of the boat body 79 . accordingly , it is not effective to turn the angle of the foil 12 and use it as a rudder . third , there is a limitation in moving the foil 12 under the submerged portion of the boat body 79 since the rear end of the oscillating crank 32 is positioned higher than the lowest portion of the boat body 79 . it is impossible to turn the foil 12 under the boat body 79 so as to convert the propulsion direction . in the human - powered boat 101 illustrated in fig2 c , the propulsion apparatus 36 having an improved structure in which the oscillating crank 32 is spread outward to increase the motion range 21 of the foil 12 is mounted . this improvement may provide an economical effect , in which the motion range 21 is expanded , by locating the foil 12 of the propulsion apparatus farther away outward from the longitudinal axis 99 of the boat body 79 , without moving the fixed position of the first pivot 11 outward by adding an outrigger on the boat body 79 . here , it is preferable that a ratio of a straight - line distance w 1 in a width direction of the boat body 79 to a straight - line distance l 2 in a longitudinal direction of the boat body 79 from the first pivot 11 to the end 34 of the oscillating crank has an arc tangent of 5 degrees or more . fig2 d is a photograph of a state in which a working demonstrator of the human - powered boat is prepared to give a demonstration according to a first embodiment of the present invention in which various functions are added and embodied while maintaining the geometry and mechanism of the human - powered boat 101 in the top plan view illustrated in fig2 c . according to results of a performance test , the human - powered boat may move at a speed that is greater than a walking speed despite the rider is a child having weak physical strength and the boat causes large propulsion resistance . it is also confirmed that previous education or practice is unnecessary when the propulsion apparatus 36 is initially used , and a reverse propulsion function is unnecessary because the boat is easily changed in direction . this may be impossible or very difficult in case where a child rows a general oar . the results of the performance test confirm that various functional limitations do not have significant effect on product value due to maximally simplified structure . therefore , the human - powered boat and the human - powered propulsion apparatus according to the present invention may take the above - described embodied functional limitations as technical features of the present invention . the functional limitations of the human - powered boat and the human - powered propulsion apparatus according to the present invention will be described in detail as follows with reference to fig2 a to 2c . first , it is impossible to tilt the oscillating crank 32 through the vertical movement of the rider &# 39 ; s arm without tilting the first rotation axis 55 . this may limit a motion form of the oscillating crank 32 during movement , and thus , the allowable motion may only be the oscillation about the first rotation axis 55 . thus , since an erroneous operation of the rider ( erroneous arm operation ) during movement does not cause a tilting of the oscillating crank 32 ( about a center line in a longitudinal direction of the boat body 79 or a center line in a width direction of the boat body 79 ), the propulsion force of the foil 12 may be generated in the uniform direction to improve the propulsion efficiency . at the same time , the rider may move freely without having a concern of the mistake thereof . second , the maximum motion range 21 of the foil 12 does not cross the longitudinal axis 99 of the boat body 79 . thus , the function of each of the propulsion apparatuses 35 and 36 as a static rudder may be limited . however , since the propulsion apparatus according to the present invention generates the propulsion force on the side of the boat body 79 , the direction change may be enabled by causing a difference in left and right propulsion forces of the boat body 79 . as a result , a dynamic rudder function is maintained as ever . third , when the maximum motion range 21 of the foil 12 and ‘ the area of the boat body submerged in the water ( a plane of draft )’ are vertically projected onto the same virtual horizontal plane , the portion overlapped by each other may be less than 30 % of the total area of the maximum motion range 21 . thus , the range in which the propulsion force is generated may be limited in size . here , a smaller overlapping portion is preferable , but the size percentage of overlapped portion is set under consideration of a change in draft according to loaded weight . in the second and third functions , each of the propulsion apparatuses is limited in size and capacity . if the propulsion apparatus mounted on the side of the boat body 79 operates to cross the longitudinal axis 99 of the boat body 79 , the oscillating crank 32 may be elongated , or a power transmission device may be added thereby increasing a size of the propulsion apparatus . therefore , this functional limitation may be necessary to simplify the propulsion apparatus . since it has a clear limitation to improve the propulsion efficiency by increasing the maximum motion range of the foil 12 under the condition in which the limited human power is used as input power , this limitation may be preferable in consideration of the ‘ scale efficiency ’. also , if the propulsion apparatus widely operates under the area of the boat body 79 that is submerged in the water , the portion of the oscillating crank 32 , which is submerged in the water increases ( because the depth of the boat body 79 generally increases in cross - section toward a middle portion thereof ) thereby causing unnecessary propulsion resistance . thus , this limitation may act as a direct pulse effect in improving of the propulsion efficiency . as described above , the present invention adopts the three functional limitations to maximize the simplicity of the apparatus while maintaining the propulsion efficiency and obtain the reflective improvement in performance from each of the limitations . at a word , removing unnecessary ideas may improve the values of products . the human - powered boat according to the first embodiment 101 of the present invention will be described in detail with reference to fig3 a to 3c . referring to the perspective view of fig3 a and the top plan view of fig3 b , the human - powered boat 101 according to the present invention has a structure in which two l - shaped propulsion apparatuses 36 and 36 ′ are mounted on an inflatable boat body 179 having a predetermined length and width and moving forward , and bilaterally symmetrical to each other with respect to the longitudinal axis 99 of the boat body 179 . each of the propulsion apparatuses 36 and 36 ′ illustrated in fig3 b is in an idle state . in detailed description of position and configuration of the propulsion apparatuses 36 and 36 ′, mounting means 37 and 37 ′ may be coupled to positions that are away by a predetermined distance outward from the longitudinal axis 99 to left and right sides of the boat body 179 , and the propulsion apparatuses 36 and 36 ′ each of which has an l - shaped oar are respectively coupled to the mounting means 37 and 37 ′. here , the mounting means 37 and 37 ′ may provide first pivots 11 and 11 ′ to the propulsion apparatuses 36 and 36 ′ coupled thereto , respectively . thus , the propulsion apparatuses 36 and 36 ′ may overall oscillate about the first pivots 11 and 11 ′, respectively . oars &# 39 ; looms , which determine the whole shapes of the propulsion apparatuses in fig3 b , may be formed by coupling handle cranks 31 and 31 ′ to oscillating cranks 32 and 32 ′. it is seen that the first pivots 11 and 11 ′ are positioned on places at which the handle cranks 31 and 31 ′ and the oscillating cranks 32 and 32 ′ meet to be coupled to each other . each of the handle cranks 31 and 31 ′ has a predetermined length and is placed in a width direction of the boat body 179 so that an outer end thereof is coupled to each of the first pivots 11 and 11 ′. also , each of the oscillating cranks 32 and 32 ′ has a predetermined length and is placed in a longitudinal direction of the boat body 179 so that a front end thereof is coupled to each of the first pivots 11 and 11 ′. here , it is preferable that each of the handle cranks 31 and 31 ′ and each of the oscillating cranks 32 and 32 ′ are coupled to each other at an angle that is approximately perpendicular to each other . however , the angle may be adjusted according to a position of the rider or a structure of the boat body 179 . also , each of plate - shaped foils 12 and 12 ′, each of which has a length and height , is coupled to a rear end of each of the oscillating cranks 32 and 32 ′ in a longitudinal direction of the boat body 179 . when the rider seats behind the handle cranks 31 and 31 ′ and grips them by hands and then alternately move the handle cranks 31 and 31 ′ forward and backward , the foils 12 and 12 ′ may oscillate in a left and right direction about each of the first pivots 11 and 11 ′ to generate propulsion force . this operation may correspond to forward - facing rowing in which the rider faces an advancing direction of the boat body 179 and moves the boat . fig3 c illustrates a right side view of the human - powered boat according to the first embodiment of the present invention . here , the handle crank 31 is positioned above the mounting means 37 , and the oscillating crank 32 is positioned below the mounting means 37 . as shown in the drawing , it is preferable that the oscillating crank 32 is positioned above the water surface and thus does not contact the water surface during the operation , and the whole of the foil 12 may be submerged under the water surface if possible . the human - powered propulsion apparatus according to the present invention may represent a combination of the mounting means and the propulsion apparatus . fig4 a to 4c are views of the human - powered propulsion apparatus of fig3 a according to the first embodiment of the present invention . only the propulsion apparatus 36 mounted on the left side of the boat body 179 and operated by a left hand of the rider and the mounting means 37 fixing the propulsion apparatus 36 to the boat body 179 are illustrated . the mounting means 37 positioned on the side of the boat body 179 provides a first rotation axis 55 in a vertical direction to the propulsion apparatus 36 paired therewith . the propulsion apparatus 36 includes a rotational post 30 fixed in position by the mounting means 37 to rotate about the first rotation axis 55 , a handle crank 31 having a predetermined length and placed in a width direction of the boat body 179 so that an outer end thereof is coupled to an upper portion of the rotational post 30 , an oscillating crank 32 having a predetermined length and placed in a longitudinal direction of the boat body 179 so that a front end thereof is coupled to the rotational post 30 , and a plate - shaped foil 12 having a predetermined length and width and coupled to a rear end of the oscillating crank 32 in a longitudinal direction of the boat body 179 . when the rider grasps the handle crank 31 and alternately move forward and backward , the foil 12 oscillates about the first rotation axis 55 to generate propulsion force . referring to the plan view of fig4 b , when the position of the first rotation axis 55 is expressed as the first pivot 11 , a ratio w 1 / l 2 of a straight - line distance w 1 from the first pivot 11 to an end of the oscillating crank 32 in a width direction of the boat body 179 to a straight - line distance l 2 from the first pivot 11 to an end 34 of the oscillating crank 32 in a longitudinal direction of the boat body 179 may has an arc tangent value of 5 degrees or more . according to the geometry , a sufficient motion range 221 in which the foil 12 oscillates in the left and right directions may be secured although the mounting means 37 is closely coupled to the side of the inflatable boat body 179 . also , if the mounting means 37 is modified in shape like an outrigger so that the first pivot 11 is positioned more away from the boat body 179 , the motion range of the foil 12 may increase without spreading a rear portion of the oscillating crank to the outside of the boat body 179 . referring to the right side view of fig4 c , a rear end 34 of the oscillating crank 32 has a height less by a predetermined height h 1 than that of an outer end 33 of the handle crank 31 . this is done because the height at which the rider easily moves an arm is higher than the water surface . also , the rear end 34 of the oscillating crank 32 may be positioned higher than the lowest portion of the boat body 179 . this is intended to reduce the propulsion resistance during the operation by minimizing the portion of the oscillating crank 32 , which is submerged under the water surface . in addition , in the structure in which the oscillating crank 32 and the foil 12 are coupled to each other , a flapping hinge 67 having a rotation axis 66 in a vertical direction is coupled to the rear end of the oscillating crank 32 , and then , the foil 12 is coupled to the flapping hinge 67 in a longitudinal direction of the boat body 179 . thus , since the foil 12 horizontally rotates at a predetermined angle θ about the rotation axis 66 provided by the flapping hinge 67 , the foil 12 has a specific pitch in generating propulsion force , like a propeller . here , the rotation axis 66 provided by the flapping hinge 67 may be the same as the rotation axis provided by the second pivot 13 , which is illustrated in fig1 a , 2c , and 4b . according to the above - described technical knowledge of the oscillating foil , as illustrated in fig4 c , it is preferable that the foil 12 has a shape that is vertically elongated on the whole , so that the foil 12 has a height greater than a length thereof , also , it is preferable that a rear portion of the foil 12 is more flexible than a front portion of the foil 12 when a side surface of the foil 12 is divided into two front and rear portions by using a virtual vertical center line 88 . the human - powered propulsion apparatus according to the first embodiment of the present invention will be more particularly described with reference to exploded views and operations illustrated in fig5 a to 5g . referring to the exploded view of fig5 a , in the propulsion apparatus 36 having the structure in which the rotational post 30 and the handle crank 31 are coupled to each other , a motion hinge 77 having a rotation axis 771 in a longitudinal direction of the boat body 179 is coupled to an upper portion of the rotational post 30 , and an outer end of the handle crank 31 is coupled to the motion hinge 77 in a width direction of the boat body 179 . thus , as illustrated in the front view of fig5 b , the handle crank 31 may oscillate at a predetermined angle about the rotation axis provided by the motion hinge 77 . as a result , when the rider grasps and rows the handle crank 31 , an upward and downward motion may be added to a forward and backward motion to allow the rider &# 39 ; s hand moves along an oval path at if the rider rows a general oar . however , although the rider &# 39 ; s arm movement is free as described above , the motion transmitted to the oscillating crank 32 in fig5 a may be only the oscillation about the first rotation axis 55 . particularly , the motion hinge 77 may be provided by coupling a first coupling element 774 coupled to the handle crank 31 to a second coupling element 773 coupled to the rotational post 30 by inserting a hinge pin 772 having a rotation axis 771 in a longitudinal direction of the boat body 179 . as illustrated in fig5 b , it is preferable that the vertical oscillating motion range of the handle crank 31 is limited from a horizontal line to a vertical line . this may be easily realized by forming an l - shaped hooking portion 775 in the second coupling element 773 . referring to the exploded view of fig5 c , in the propulsion apparatus 36 having the structure in which the oscillating crank 32 and the foil 12 are coupled to each other , a retracting hinge 78 having a rotation axis 781 in a width direction of the boat body 179 is coupled to the rear portion of the oscillating crank 32 , and the foil 12 is coupled to the retracting hinge 78 in a longitudinal direction of the boat body 179 . thus , as the right side view illustrated in fig5 d , when the foil 12 collides with an underwater obstacle 789 , the foil 12 may rotate at a predetermined angle about the rotation axis provided by the retracting hinge 78 and be lifted upward to reduce the risk of damage . here , it is preferable that the vertical oscillating motion range of the foil 12 is limited from a vertical line to horizontal line . this may be easily realized by forming an l - shaped hooking portion 783 in a third coupling element . as described above , it is seen that two hinges such as the flapping hinge 67 and the retracting hinge 78 may be added when the oscillating crank 32 and the foil 12 of the human - powered propulsion apparatus are coupled to each other . explaining a specific configuration , in which the two hinges are added at once , with reference to fig5 c , a third coupling element 783 is coupled to the rear end of the oscillating crank 32 , and then , a fourth coupling element 784 is coupled by using a horizontal hinge pin 782 to constitute the retracting hinge 78 . subsequently , a fifth coupling element 674 is coupled to a rear portion of the fourth coupling element 784 by using a vertical hinge pin 672 to constitute the flapping hinge 67 . the foil 12 is coupled to a rear portion of the fifth coupling element 674 in a longitudinal direction of the boat body 179 . here , the fourth coupling element 784 includes at least one or more rings 785 that are spaced away at a predetermined distance from each other along the second rotation axis 66 provided by the vertical hinge pin 672 , and the fifth coupling element 674 includes at least one or more rings 675 that are disposed to miss the rings of the fourth coupling element . thus , when the fourth coupling element 784 and the fifth coupling element 674 are coupled to each other , the rings 786 and 675 respectively provided at the elements may be engaged with each other like gears and then strung downward from top to bottom in a line by using the vertical hinge pin 672 and fixed in position . in the coupling structure as described above , two hinge &# 39 ; s function may be realized at the same time with small number of components . also , since it is impossible to disassemble the flapping hinge 67 without withdrawing the hinge pin 782 constituting the retracting hinge 78 , the flapping hinge 67 that has to endure vibrations may be improved in durability . here , at least one stopping protrusion 786 is disposed on each of left and right sides of the fourth coupling element 784 , and at least one stopping protrusion 676 is disposed on each of left and right sides of the fifth coupling element 674 . since the stopping protrusions 786 and 676 are positioned at the same height when being coupled , if the foil 12 starts to rotate in one direction from the idle state illustrated in fig5 e ( a rear view ) with respect to the oscillating crank 32 , the rotation stops when the stopping protrusions 786 and 676 meet together , so that the maximum rotation range of the fin is defined . the oscillation of the foil 12 with respect to the oscillating crank 32 is illustrated in the top plan view of fig5 g . here , the second rotation axis 66 provided by the flapping hinge 67 may be the same as the second pivot 13 on the drawing . angles β and β ′ at which the foil rotates in a left or right direction with respect to the idle state may be different from each other . in this case , it is preferable that the internal angle positioned closer to the boat body 179 is greater than another angle ( β & gt ; β ′). in the human - powered propulsion apparatus according to the first embodiment of the present invention , since the oscillating crank 32 is coupled to a lower portion of the rotational post 30 , it is difficult to detach or mount the propulsion apparatus 36 from or to the mounting means 37 . however , in case of that the boat body 179 is inflatable as described in the human - powered boat according to the first embodiment of the present invention , or a potion of the boat body 179 , on which the mounting means is fixed , is provided as an inflatable float , if the mounting means 37 may be divided into at least two components 371 and 372 by using at least one vertical cross - section as illustrated in the perspective view of fig6 a , contact surfaces of at least two components constituting the mounting means 37 may be spread to easily detach the propulsion apparatus 36 from the mounting means 37 in a state in which air within the boat body 179 may be discharged to reduce an internal pressure as illustrated in fig6 b . as described above , the vertically divided mounting means 37 may be manufactured through injection molding by using a simple mold and thus reduced in manufacturing costs . in the human - powered boat according to the first embodiment of the present invention , the boat body is for a one - seater boat and two propulsion apparatuses 36 and 36 ′ positioned bilaterally symmetrical to each other are mounted on the boat body . in case of a two or more - seater boat on which two or more persons may ride side by side at left and right sides , each of the propulsion apparatuses may be asymmetrically disposed on left and right sides one another . thus , regarding the mounting of the propulsion apparatuses , the symmetrical feature of the propulsion apparatuses may be flexibly applicable . in some cases , the present invention may include a structure in which only one propulsion apparatus is mounted on one side of the boat body 179 , and the general oar is rowed at an opposite side . fig7 a to 7e are views of a human - powered propulsion apparatus according to a second embodiment of the present invention . referring to fig7 a , in a human - powered propulsion apparatus 336 according to a second embodiment of the present invention , it is confirmed that an oscillating crank 322 is coupled to an upper portion of a rotational post 30 , unlike the propulsion apparatus 36 according to the foregoing first embodiment . referring to fig7 b , the oscillating crank 322 gradually decreases in height from a portion thereof coupled to the rotational post 30 to a rear of a boat body 179 and then is coupled to a foil 12 . a shape in which the oscillating crank 322 is inclined backward and downward may provide an effect in which energy loss is less because a portion of the oscillating crank 322 , which is submerged under the water , is reduced even though the boat body 179 is deeply submerged under the water surface due to the large loadage . also , the largest advantage of the propulsion apparatus 336 having the geometry is that the propulsion apparatus 336 may be easily lifted and detached from the boat body 179 as illustrated in fig7 c . of course , even when being mounted again , the rotational post 30 may be simply inserted into the mounting means 37 to mount the propulsion apparatus 336 on the boat body 179 . furthermore , in the propulsion apparatus 336 having the structure in which the rotational post 30 and the oscillating crank 322 are coupled to each other , a folding hinge 56 having a rotation axis 561 in a width direction of the boat body 179 is added to the coupled portion between the rotational post 30 and the oscillating crank 322 . referring to fig7 d , the folding hinge 56 includes a sixth coupling element 562 coupled to the rotational post 30 , and a seventh coupling element 563 inserted into the folding hinge 56 to rotate at a fixed angle about the rotation axis 561 in a width direction of the boat body 179 and coupled to a front end of the oscillating crank 322 . the sixth coupling element 562 and the seventh coupling element 563 do not have to be separated from each other during the operation of the propulsion apparatus 336 and have to provide a function that restricts the oscillating crank 322 so that the oscillating crank 322 stops to rotate downward at a specific angle . since this is capable of being secured through a simple design change of the folding hinge 56 , such as adding of a predetermined locking means operable by a rider &# 39 ; s hand and a modification of contact surfaces of the two coupling elements 562 and 563 into uneven surfaces , its detailed description will be omitted in the present invention . due to the effect through the adding of the folding hinge 56 , the propulsion apparatus 336 may be reduced in overall volume because the oscillating crank 322 rotates upward at a predetermined angle about the rotation axis 561 provided by the folding hinge 56 and then is lifted . referring to fig7 e , the propulsion apparatus 336 is detached from the boat body 179 , and then , a handle crank 31 is folded upward with respect to a motion hinge 77 . then , the oscillating crank 322 is folded upward with respect to the folding hinge 56 , and then , a foil 12 is folded upward with respect to a retracting hinge 78 to reduce the overall volume . therefore , the propulsion apparatus 336 may be easily carried and stored . of cause , the folding hinge 56 provides the same effect when the folding hinge 56 is applied to the human - powered propulsion apparatus 36 according to the first embodiment . the handle cranks 31 and 31 ′ and the oscillating cranks 32 , 32 ,′ and 322 of the human - powered propulsion apparatus according to the present invention have to be changed in length according to the boat body 179 or a body size of the rider . for example , when the boat body 179 increases in width thereby increasing a distance from the rider &# 39 ; s position to the mounting means , it is necessary to increase a length of each of the handle cranks 31 and 31 ′. also , the increase in length of each of the oscillating cranks 32 , 32 ′ and 322 may be effective as a method for expanding the motion range of each of the foils 12 and 12 ′. thus , in the human - powered propulsion apparatus according to a third embodiment of the present invention , each of the handle cranks 31 and 31 ′ or the oscillating cranks 32 , 32 ′ and 322 may have a telescopic tube structure that is adjustable in length . since this structure is commonly found from an umbrella to a smartphone antenna , the structure will be omitted in the drawings . however , the telescope tube structure may include a stopping means for fixing the telescopic tube such after a length of the telescope tube is adjusted as a screw . or , a constituent for remotely adjusting a length of each of the oscillating cranks 32 , 32 ′ and 322 by using a string may be added . since these constituents are commonly adopted to operate a sail or rudder in the small - sized boat technical fields , their detailed descriptions will be omitted . the human - powered boat according to the second embodiment of the present invention may represent a human - powered boat in which the human - powered propulsion apparatus according to the second embodiment is mounted on the boat body 179 of the human - powered boat according to the first embodiment . similarly , the human - powered boat according to the third embodiment of the present invention may represent a human - powered boat in which the human - powered propulsion apparatus according to the third embodiment is mounted on the boat body 179 of the human - powered boat according to the first embodiment . thus , drawings with respect to the human - powered boats according to the second and third embodiments will be omitted . various features according to each of the embodiments of the present invention may be mutually applied to each other . for example , the telescope tube structure of the human - powered propulsion apparatus according to the third embodiment may be applied to the handle crank of the human - powered propulsion apparatus according to the second embodiment , and the folding hinge of the human - powered propulsion apparatus according to the second embodiment may be applied to the human - powered boat according to the first embodiment . also , the structure in which the mounting means of the human - powered boat according to the first embodiment is divided into at least two components may be applied to the human - powered boat according to the second or third embodiment . the present invention relates to the non - motorized movable human - powered boat and the human - powered propulsion apparatus thereof . particularly , the present invention may be applied to the structure in which the rider rows the oar through the forward and backward movement of the rider &# 39 ; s arm while facing the advancing direction of the boat .