Airboat and production method for airboat

Abstract

An airboat 10 according to one embodiment comprises a boat body 13 that is to be filled with gas, a bilge sheet 30 that is provided at a bilge part of the boat body 13 and has, in the width direction, a center part 30c and, as sheet regions, a right side sheet region 30s and a left side sheet region 30p, an air floor 31 that is opposite the bilge sheet 30, and a keel part 35 that is provided between the bilge sheet 30 and the air floor 31 and, when filled with gas, makes a portion of the bilge sheet 30 at the center part 30c of the bilge sheet 30 protrude toward the bottom of the water along the bow-stern direction. The keel part 35 has a first keel member 351 that is attached to the surface of the bilge sheet 30 that is opposite the air floor 31 at the center part 30c along the bow-stern direction and, when filled with gas, protrudes further toward the bottom of the water and the air floor 31 than the right side sheet region 30s and the left side sheet region 30p.

Description

Airboat and method for manufacturing airboat

[0001] The present invention relates to an airboat and a method for manufacturing an airboat.

[0002] Inflatable boats (airboats) are small boats used for leisure activities and the like. The airboat disclosed in Patent Document 1 has a keel member, which is filled with air, attached to the bottom of the boat to improve the boat's sailing performance. By using such a keel member to protrude a portion of the bottom, the airboat's straight-line running performance and wave-riding performance can be improved.

[0003] Japanese Patent Application Laid-Open No. 2002-96792

[0004] However, depending on the shape of the protruding part of the bottom of the ship, there is a risk that the water flow around the bottom of the ship will be disturbed, resulting in a decrease in sailing performance.

[0005] In one embodiment, the airboat comprises a boat body that is filled with gas, a bottom sheet that is provided on the bottom of the boat body and has a widthwise center and a seat area different from the center, a floor member that is disposed opposite the bottom sheet, and a keel portion that is provided between the bottom sheet and the floor member and that, when filled with gas, causes a portion of the bottom sheet to protrude toward the bottom of the water along a fore-and-aft direction at the center of the bottom sheet. The keel portion has a first keel member that is attached to the surface of the bottom sheet that faces the floor member along the fore-and-aft direction at the center, and that, when filled with gas, protrudes toward the bottom of the water and toward the floor member beyond the seat area.

[0006] In one embodiment, a method for manufacturing an airboat includes a boat body filled with gas, a bottom sheet provided on the bottom of the boat body, a floor member arranged opposite the bottom sheet, and a keel portion provided between the bottom sheet and the floor member, which, when filled with gas, causes a portion of the bottom sheet to protrude toward the bottom of the water along the bow-and-stern direction at the center of the width of the bottom sheet, and the keel portion, which is not filled with air, is attached to the surface of the bottom sheet facing the floor member.

[0007] According to the present invention, the navigation performance of an airboat can be improved.

[0008] 1 is a perspective view showing an airboat of an embodiment; FIG. 2 is a cross-sectional view of the airboat taken along line A-A in FIG. 1; FIG. 3 is a cross-sectional view of the airboat taken along line B-B in FIG. 2; FIG. 4 is a cross-sectional view of the airboat taken along line CC in FIG. 2; FIG. 5 is a plan view showing the airboat from above; FIG. 6 is a cross-sectional view showing the shape of the first keel member and its vicinity; FIG. 7 is a cross-sectional view showing the shape of the first keel member and its vicinity in an airboat in a comparative example; FIG. 8 is a cross-sectional view showing the shape of the first keel member and its vicinity in an airboat in a comparative example;

[0009] An airboat according to an embodiment of the present invention will now be described in detail with reference to the drawings. Fig. 1 is a perspective view of an airboat 10 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the airboat 10 taken along line A-A in Fig. 1.

[0010] <Overall Structure> The airboat 10 includes a boat body 13, a bottom sheet 30, an air floor 31, and a keel 35. The boat body 13 has a starboard tube 11, a port tube 12, and a bow tube 14. The boat body 13 has a bow 13a in which the starboard tube 11 and the port tube 12 are connected via the bow tube 14. A seat board 17 for a crew member to sit on is stretched across the starboard tube 11 and the port tube 12.

[0011] At the stern 13b of the boat body 13, the starboard tube 11 and the port tube 12 are connected via a transom board 15. An outboard motor 16 equipped with a screw 47 is attached to the transom board 15. The transom board 15 is made of, for example, wood, glass fiber reinforced resin, metal, etc.

[0012] <Boat main body 13> The starboard tube 11, port tube 12, and bow tube 14 that make up the boat main body 13 are formed using boat cloth, which is made of a base material such as polyester or nylon sandwiched between polymer layers. The hull shape of the airboat 10, which is used when filled with air (gas), is determined by the rigidity of the tubes when filled with air. For this reason, the boat main body 13 is formed using boat cloth that is resistant to stretching even when subjected to high filling pressure.

[0013] Additionally, multiple bulkheads (not shown) are provided inside the starboard tube 11 and the port tube 12. This prevents all air from being expelled from the boat body 13, even if the boat cross is damaged. When the boat body 13 is used, air is filled into the boat body 13 at a predetermined filling pressure (for example, 200 to 250 hPa).

[0014] <Bottom Sheet 30> The bottom sheet 30 is adhered to the starboard tube 11, the port tube 12, the bow tube 14, and the transom plate 15, and closes the bottom portion 13c of the boat main body 13. In other words, the bottom sheet 30 is provided on the bottom portion 13c of the boat main body 13. A first keel member 351 that constitutes the keel portion 35, which will be described in detail later, is attached by adhesion to the upper surface of the bottom sheet 30, i.e., the surface of the side of the bottom sheet 30 that does not face the bottom of the water. The bottom sheet 30 is formed using the above-mentioned boat cloth or the like.

[0015] <Air Floor 31> Figure 3 is a cross-sectional view of the airboat 10 taken along line BB in Figure 2. Figure 4 is a cross-sectional view of the airboat 10 taken along line CC in Figure 2.

[0016] The air floor 31 is a floor member of the airboat 10, and is provided on the upper surface side of the bottom sheet 30. In other words, the air floor 31 is disposed opposite the bottom sheet 30. A second keel member 352 constituting the keel portion 35, which will be described in detail later, is attached by adhesive to the underside of the air floor 31, i.e., the surface facing the bottom sheet 30.

[0017] 3 and 4, the air floor 31 comprises top sheets 32 and 33 that face each other in the vertical direction at a predetermined distance. A large number of connecting threads 34 are provided within the air floor 31, with one end of each connecting thread 34 connected to the top sheet 32 ​​and the other end connected to the top sheet 33. The distance between the facing top sheets 32 and 33 is regulated by the large number of connecting threads 34, allowing the air floor 31 to expand into a plate shape when filled with air.

[0018] The top sheets 32, 33 are made of the above-mentioned boat cloth or the like, and the connecting threads 34 are made of, for example, polyester or nylon. When the air floor 31 is used, the air floor 31 is filled with air at a predetermined filling pressure (for example, 500 to 800 hPa).

[0019] <Keel portion 35> Figure 5 is a plan view showing the airboat 10 from above. Note that the air floor 31 is omitted from Figure 5.

[0020] As shown in Figure 5, the keel 35 is provided between the bottom sheet 30 and the air floor 31. The keel 35 is located in the center of the boat body 13 in the width direction (starboard direction) and along the bow-stern direction of the airboat 10. The keel 35 is composed of a first keel member 351 located on the stern side and a second keel member 352 located on the bow side. Specifically, the second keel member 352 is located closer to the bow than the first keel member 351.

[0021] Air can be filled inside the first keel member 351 and the second keel member 352. When air is filled into the first keel member 351 and the second keel member 352, the keel portion 35 causes a part of the bottom sheet 30 to protrude toward the bottom of the water in the width direction of the airboat 10, i.e., in the fore-and-aft direction at the central portion 30c of the bottom sheet 30.

[0022] <Second Keel Member 352> The second keel member 352 is attached to the underside of the air floor 31. In other words, the second keel member 352 is attached to the surface of the air floor 31 facing the bottom sheet 30, and extends along the fore-aft direction at the center portion 30c of the width of the bottom sheet 30. As shown in FIG. 5, the second keel member 352 has a first tapered portion 36 that gradually expands from the bow side to the stern side, and a second tapered portion 37 that is connected to the first tapered portion 36 and gradually narrows toward the stern side. By filling the second keel member 352 with air, the bottom sheet 30 can be caused to protrude downward toward the bottom of the water. More specifically, as shown in FIG. 2, the downward protrusion of the bottom sheet 30 is increased near the position where the first tapered portion 36 and the second tapered portion 37 are connected. As a result, the sailing performance of the airboat 10 can be improved.

[0023] The second keel member 352 is formed using the above-mentioned boat cloth, etc. When the second keel member 352 is used, air is filled into the second keel member 352 at a predetermined filling pressure (for example, 350 hPa).

[0024] <First keel member 351> The first keel member 351 is attached to the upper surface of the bottom sheet 30. In other words, the first keel member 351 is attached to the surface of the bottom sheet 30 on the side facing the air floor 31. More specifically, the first keel member 351 is attached to the bottom sheet 30 by adhesive in the center portion 30c in the width direction of the bottom sheet 30 along the fore-aft direction. In addition, the first keel member 351 is provided with a supply port 353 for supplying air to be filled inside.

[0025] Fig. 6A is a cross-sectional view of the first keel member 351 when air is filled through the supply port 353. Specifically, Fig. 6A is a partial cross-sectional view showing an enlarged view of the area indicated by region R in Fig. 3. Fig. 6B is a cross-sectional view of the first keel member 351 when air is not filled. As shown in Fig. 6A, the first keel member 351 filled with air has a thickness in the vertical direction compared to when it is not filled with air.

[0026] 3, 5, 6A, and 6B, a reinforcing cloth 50 is provided on the upper surface of the first keel member 351. The reinforcing cloth 50 is attached to the upper surface of the first keel member 351 and to parts of the right seat area 30s and the left seat area 30p, which are seat areas adjacent in the left-right direction to the central portion 30c of the bottom sheet 30. In other words, the first keel member 351 is attached to the bottom sheet 30 from above by the reinforcing cloth 50. The reinforcing cloth 50 is formed using, for example, the above-mentioned boat cloth or the like.

[0027] The first keel member 351 has the same structure as the air floor 31 described above. That is, the first keel member 351 comprises a first top sheet 44 and a second top sheet 45 that face each other with a predetermined gap between them. The first top sheet 44 faces the air floor 31, and the second top sheet 45 faces the bottom sheet 30. The reinforcing fabric 50 described above is attached to the upper surface of the first top sheet 44, and the lower surface of the second top sheet 45 is attached to the upper surface of the bottom sheet 30. Specifically, as shown in Figure 6B, the first keel member 351 is attached to the bottom sheet 30 in an unfilled state, i.e., when the first keel member 351 is not filled with air.

[0028] Furthermore, a large number of connecting threads (threads) 46 are provided within the first keel member 351. One end of the connecting thread 46 is connected to the first topsheet 44, and the other end of the connecting thread 46 is connected to the second topsheet 45. In other words, the distance between the opposing first topsheet 44 and second topsheet 45 is regulated by the large number of connecting threads 46. Therefore, as shown in Figure 3, the first keel member 351 filled with air is inflated into a plate-like shape with a rectangular cross section. The first topsheet 44 and second topsheet 45 are made of the above-mentioned boat cloth or the like, and the connecting threads 46 are made of, for example, polyester or nylon.

[0029] When the first keel member 351 is used, air is filled into the first keel member 351 at a predetermined filling pressure. This filling pressure is higher than the filling pressure (350 hPa) for the second keel member 352, and is, for example, 600 hPa to 700 hPa, with a maximum of approximately 1000 hPa. As described above, the first keel member 351 is attached to the bottom sheet 30 so as to be pressed down from above by the reinforcing cloth 50, and therefore the strength of the upper part of the first keel member 351 is increased by the first surface sheet 44 and the reinforcing cloth 50. This makes it possible to fill the first keel member 351 with air at a high filling pressure.

[0030] Because the first keel member 351 is filled with air at a higher filling pressure than the second keel member 352, the first keel member 351 is harder than the second keel member 352. This suppresses the action of water pressure on the stern end of the keel portion 35, and suppresses deformation of the keel portion 35. In other words, the deformation of the first keel member 351 can be suppressed and the bottom shape can be maintained, thereby improving the sailing performance of the airboat 10. Furthermore, because deformation of the first keel member 351 is suppressed, the water flow can be smoothly guided toward the propeller 47, allowing the propeller 47 to reliably capture water and stabilize propulsion.

[0031] As described above, the air-filled first keel member 351 has a rectangular cross section. Specifically, as shown in Figures 5 and 6A, the air-filled first keel member 351 is formed by an upper surface 51 on the air floor 31 side, a lower surface 52 on the bottom sheet 30 side, a right surface 53, a left surface 54, a bow surface 55, and an aft surface 56. The right surface 53 connects the upper surface 51 and the lower surface 52 on the starboard side. The left surface 54 connects the upper surface 51 and the lower surface 52 on the port side. The bow surface 55 connects the upper surface 51 and the lower surface 52 on the bow side. The aft surface 56 connects the upper surface 51 and the lower surface 52 on the bow side.

[0032] As described above, because the reinforcing fabric 50 is attached to the upper surface of the first top sheet 44, the upper surface 51 is formed by the region of the first top sheet 44 that includes the center of the boat body 13 in the width direction. Furthermore, because the lower surface of the second top sheet 45 is attached to the bottom sheet 30, the lower surface 52 is formed by the region of the second top sheet 45 that includes the center of the boat body 13 in the width direction. The right surface 53 is formed by the starboard-side end regions of the first top sheet 44 and the second top sheet 45. The left surface 54 is formed by the port-side end regions of the first top sheet 44 and the second top sheet 45.

[0033] As a result, the upper surface 51 of the air-filled first keel member 351 protrudes upward (i.e., toward the air floor 31) beyond the right seat area 30s and the left seat area 30p of the bottom sheet 30. Also, the lower surface 52 of the first keel member 351 protrudes downward (i.e., toward the bottom of the water) beyond the right seat area 30s and the left seat area 30p. In this case, the ratio of the amount of upward protrusion of the upper surface 51 to the amount of downward protrusion of the lower surface 52 is approximately 1:1. However, the ratio of the amount of protrusion of the upper surface 51 to the lower surface 52 is not limited to 1:1.

[0034] The right surface 53 is formed by a part of the first top sheet 44 and a part of the second top sheet 45, and the left surface 54 is formed by a part of the first top sheet 44 and a part of the second top sheet 45. In other words, the lower parts of the right surface 53 and the lower parts of the left surface 54 of the first keel member 351 filled with air are attached to the bottom sheet 30. Therefore, when the first keel member 351 is filled with air, the side surfaces 30A, 30B of the bottom sheet 30 that protrude toward the bottom of the water are shaped to fit the right surface 53 and left surface 54 of the first keel member 351.

[0035] 6A, the side surfaces 30A, 30B of the bottom sheet 30 are shaped to conform to the right surface 53 and the left surface 54, so the side surfaces 30A, 30B are connected to the right seat area 30s and the left seat area 30p without forming any recesses or protrusions. As a result, the areas where the side surfaces 30A and the right seat area 30s are connected and the areas where the side surfaces 30B and the left seat area 30p are connected are sharp and extend along the fore-aft direction.

[0036] 7A and 7B are enlarged partial cross-sectional views of an airboat 10r according to a comparative example, in which the same or substantially the same components as those in the airboat 10 of the embodiment described above are denoted by the same reference numerals.

[0037] 7A, the first keel member 351 is attached to the bottom surface (bottom surface) of the bottom sheet 30. In this case, the first top sheet 44 of the first keel member 351 is attached to the bottom surface of the bottom sheet 30, and is attached to the bottom surface of the bottom sheet 30 from below the second top sheet 45 by a reinforcing cloth 50r. In other words, the reinforcing cloth 50r is provided across the second top sheet 45 and the bottom surface of the bottom sheet 30.

[0038] To prevent the reinforcing fabric 50r from peeling off due to the influence of water currents while the airboat 10r is sailing, the reinforcing fabric 50r is attached along the outer contour of the first keel member 351, i.e., along the lower surface 52, right surface 53, and left surface 54. As a result, as shown in Figure 7, recesses 30q, which are spaces, are formed between the upper right and left ends of the first keel member 351 and the reinforcing fabric 50r and the bottom surface of the bottom sheet 30. When the airboat 10r is sailing, the water currents are disturbed in these recesses 30q, reducing the straight-line sailing ability of the airboat 10r.

[0039] 7B, the first keel member 351 is attached to the underside of the air floor 31 (the side facing the bottom sheet 30). In this case, when the first keel member 351 is filled with air, the first keel member 351 and the bottom sheet 30 are not bonded together, and therefore the side surfaces 30A, 30B of the bottom sheet 30 do not conform to the right and left surfaces 53, 54 of the first keel member 351. Because the shapes of the side surfaces 30A and 30B are sharp and do not extend in the bow-stern direction, the sailing performance of the airboat 10r is reduced due to resistance received from underwater, etc.

[0040] In contrast, in the airboat 10 of this embodiment, as shown in Fig. 6A, the side surfaces 30A, 30B are not formed with recesses or protrusions, but rather have a sharp shape extending along the bow-stern direction. This reduces the occurrence of water turbulence and underwater resistance, as occurs with the airboat 10r of the comparative example, during sailing of the airboat 10, thereby improving the sailing performance of the airboat 10. In particular, airboats are generally lightweight and prone to skidding when moving forward or backward due to water turbulence. However, the improved sailing performance of the airboat 10 of this embodiment reduces skidding.

[0041] <Method of Manufacturing the Airboat 10> Figure 8 is a flowchart illustrating the steps of the method of manufacturing the airboat 10 described above. In step S1, the boat body 13 is prepared. In step S2, the first keel member 351 is prepared. At this time, the first keel member 351 is not filled with air. In step S3, the unfilled first keel member 351 is attached to the upper surface of the bottom sheet 30 of the boat body 13, i.e., the surface that faces the air floor 31 when the air floor 31 is attached. At this time, because the first keel member 351 is not filled with air, it is not inflated into a plate shape and is in a flat state. Therefore, the first keel member 351 attached to the bottom sheet 30 is in the state shown in Figure 6B.

[0042] In step S4, the reinforcing fabric 50 is attached to the upper surface of the first keel member 351, i.e., the first top sheet 44 and a portion of the right seat region 30s and a portion of the left seat region 30p of the bottom sheet 30. In step S5, the air floor 31, to which the second keel member 352 is attached, is placed from above the bottom sheet 30 to which the first keel member 351 is attached. The airboat 10 is manufactured through the above steps.

[0043] By filling the first keel member 351 of the airboat 10 manufactured as described above with air, the first keel member 351 expands to have a rectangular cross section, as shown in Fig. 6A. The first keel member 351 then protrudes downward (i.e., toward the bottom of the water) and upward (toward the air floor 31) from the right seat area 30s and the left seat area 30p. In other words, by using the manufacturing method described above, it is possible to easily manufacture an airboat 10 in which the first keel member 351 protrudes downward and upward from the right seat area 30s and the left seat area 30p.

[0044] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments that are conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0045] In the embodiment, the first keel member 351 has a rectangular cross section, but it may have a circular or elliptical cross section. However, even in this case, the second top sheet 45 of the first keel member 351 is attached to the surface of the bottom sheet 30 facing the air floor 31, and the reinforcing fabric 50 is attached from above so as to straddle the first top sheet 44 and the bottom sheet 30.

[0046] In the embodiment, the second keel member 352 is provided on the air floor 31. However, this is not limited to this, and the second keel member 352 may be provided on the bottom sheet 30. Alternatively, the keel portion 35 does not have to have the second keel member 352. In this case, it is preferable that the first keel member 351 extends further toward the bow than shown in Figures 2, 5, etc.

[0047] The length of the first keel member 351 extending from the stern side toward the bow side of the boat body 13 may be adjusted as appropriate depending on the size of the airboat 10. In this case, the first keel member 351 may have a length from the stern 13b (transom plate 15) toward the bow 13a that is approximately 30% of the fore-aft length of the airboat 10, or may have a length that is approximately 50% or less of the fore-aft length, or may have a length that is approximately 90% or less of the fore-aft length. In other words, it is sufficient that the first keel member 351 is provided at least on the stern side.

[0048] In the above description, the air filling pressures for the boat body 13, the air floor 31, the first keel member 351, and the second keel member are exemplified, but the filling pressures are not limited to the exemplified values. The filling pressures may be adjusted as appropriate depending on the type of boat cross, etc. Furthermore, the gas to be filled is not limited to air, but may be nitrogen, etc.

[0049] 10 Airboat, 11 Starboard tube, 12 Port tube, 13 Boat body, 14 Bow tube, 30 Bottom sheet, 30c Center portion, 30p Left side seat area, 30q Recess, 30s Right side seat area, 31 Air floor, 35 Keel portion, 44 First surface sheet, 45 Second surface sheet, 46 Connecting thread (thread), 50 Reinforcing fabric, 51 Upper surface, 52 Lower surface, 53 Right surface, 54 Left surface, 351 First keel member, 352 Second keel member

Claims

1. An airboat comprising: a boat body that is filled with gas; a bottom sheet that is provided on the bottom of the boat body and has a widthwise center and a seat area different from the center; a floor member that is arranged opposite the bottom sheet; and a keel portion that is provided between the bottom sheet and the floor member and that, when filled with gas, causes a part of the bottom sheet to protrude toward the bottom of the water along the fore-and-aft direction at the center of the bottom sheet, wherein the keel portion is attached to the surface of the bottom sheet that faces the floor member along the fore-and-aft direction at the center, and has a first keel member that, when filled with gas, protrudes toward the bottom of the water and toward the floor member beyond the seat area.

2. An airboat according to claim 1, wherein the first keel member has a first surface sheet facing the floor member and a second surface sheet attached to the bottom sheet, and a reinforcing material attached across a portion of the sheet area of the first surface sheet and the bottom sheet.

3. An airboat according to claim 2, wherein said first keel member has a rectangular cross section when filled with gas.

4. An airboat according to claim 3, wherein the first surface sheet and the second surface sheet are connected by a large number of threads.

5. An airboat according to claim 4, wherein the first keel member is provided at least on the stern side of the boat body.

6. An airboat according to claim 5, wherein the keel portion is provided on the bow side of the first keel member and is provided with a second keel member extending along the bow-stern direction at the center in the width direction.

7. An airboat according to claim 6, wherein the second keel member is provided on a surface of the floor member that faces the bottom sheet.

8. An airboat according to claim 7, wherein the filling pressure of the air filled in the first keel member is higher than the filling pressure of the air filled in the second keel member.

9. A method for manufacturing an airboat comprising a boat body filled with gas, a bottom sheet attached to the bottom of the boat body, a floor member arranged opposite the bottom sheet, and a keel portion provided between the bottom sheet and the floor member, which, when filled with gas, causes a part of the bottom sheet to protrude toward the bottom of the water along the bow-and-stern direction at the center of the width of the bottom sheet, wherein the keel portion, which is not filled with air, is attached to the surface of the bottom sheet facing the floor member.

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