US3812805A

US3812805A - Inflatable pontoon boat

Info

Publication number: US3812805A
Application number: US00296784A
Authority: US
Inventors: D Forssell; H Folson
Original assignee: Vector Co
Current assignee: Vector Co
Priority date: 1972-10-12
Filing date: 1972-10-12
Publication date: 1974-05-28
Anticipated expiration: 1991-05-28
Also published as: DE2350762A1

Abstract

There is described a boat having two rubberized fabric inflatable pontoons and two separate open box-like hulls. The hull sections are joined to the pontoons by a beading on the pontoons which engages slots on either side of the hull sections. The pontoons are locked into position when they are inflated.

Description

United States atet Forssell et a1.

INFLATABLE PONTOON BOAT US. Cl. 114/61, 9/2 A, 9/2 S Int. Cl 8631) 1/12, B63b 7/08 Field of Search 9/1 R, 2 AU, 11 A; 114/61,

References Cited UNITED STATES PATENTS 8/1956 Potts et al 114/61 'nlllll 1111 3,812,805 1451 May 28, 1974 3,391,883 7/1968 Curtis 244/31 3,531,809 10/1970 Hegg...

3,608,112 9/1971 lrgens 9/2 A FOREIGN PATENTS OR APPLICATIONS 1,222,813 8/1966 Germany 9 2 A Primary ExaminerGeorge E. A. Halvosa Assistant Examiner-Sherman D. Basinger Attorney, Agent, or FirmChristie, Parker & Hale [5 7 ABSTRACT There is described a boat having two rubberized fabric inflatable pontoons and two separate open box-like hulls. The hull sections are joined to the pontoons by a beading on the pontoons which engages slots on either side of the hull sections. The pontoons are locked into position when they are inflated.

12 Claims, 7 Drawing Figures SATENTEBHAY 28 1974 SHEEY 1 [if 4 PAT VIA I ENTED Y W? 3,812,805

sumanra INFLATABLE PONTOON BOAT FIELD OF THE INVENTION This invention relates to inflatable boats, and more specifically to a boat of catamaran design which can be readily assembled and disassembled.

BACKGROUND OF THE INVENTION The development of inflatable rafts and boats has received increasing attention because of the inherent advantages of this type of craft and proven safety, lightness and compactness, portability, load capacity and ruggedness under severe operating conditions. However, prior designs of inflatable boats have suffered from one or more of the following limitations. The allinflatable boats, in which an air tube extends completely around the boat, lacks good performance and movement through the water. Their flat, flexible bot tom and shallow draft make them difficult to handle, provide poor passenger comfort in regard to standing or sitting, and the internal flexibility makes it difficult to drive them under power since the distribution of the loads becomes difficult. At the same time they are hard to row because of their ungainly shape and do not adapt themselves to accepting a sailing rig.

For this reason, attempts have been made to combine the features of rigid construction with an inflatable hull design in order to gain portability and compactness when not in use and at the same time achieve some of the performance characteristics of an entirely rigid boat. Attempts have been made to combine rigid transoms and rigid superstructure, adding a floor to the hull to add stiffness. The inflatable portion of such boats may be in the form ofa single V- or U-shaped inflatable tube or may be in the form of two separate inflatable tubes in the form of pontoons. Known designs of this type have not proved readily portable or have proved difficult to assemble and disassemble, have lacked adaptability to use either as a power boat or as a sail boat, or not provided the passengers with adequate comfort and safety.

SUMMARY OF THE INVENTION The present invention is directed to an improved inflatable boat which combines a rigid hull structure with inflatable pontoons having the characteristics of a catamaran design. The boat design makes it extremely simple to assemble and disassemble, to store the boat in a small space when disassembled, and yet when assembled to provide good performance when used either as a rowboat, a powerboat or a sailboat. The boat has a high safety factor in that it remains afloat even if air is lost from the inflated pontoons.

These and other advantages of the present invention are achieved by a boat which utilizes a pair ofinflatable pontoons which are joined when in assembled condition by a pair of box-like rigid hull sections. These hull sections, when disassembled, are arranged to nest one inside of the other for compact storage. The hull sections are secured to and supported between the pontoons by means of beading secured along the side of the pontoons which are pulled into slots extending along either side of the hull sections before the pontoons are inflated. After the pontoons are inflated, the pontoons wedge against the side of the hull sections, placing the beading under tension and securely locking the pontoons to the hull sections.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the invention reference should be made to the accompanying drawings wherein:

FIG. I is a top view of the boat when fully assembled;

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings in detail, the numeral 10 indicates generally the hull of the boat and in the preferred embodiment includes two separate sections, the front section being indicated at 12 and the rear section being indicated at 14. Each section is in the form of a substantially rectangular open box. However, as seen in the drawings, the two

sections

12 and 14 are not identical, but identical sections could be used if preferred. The front hull section 12 includes a substantially flat bottom 16, a front wall 18, rear wall 20, and

side walls

22 and 24. The rear section 14 similarly has a flat bottom wall 26, a front wall 28, rear wall 30 and

side walls

32 and 34. It should be noted that the front wall 18 of the front section and the

side walls

22 and 24 of the front section, and also

side walls

32 and 34 of the rear section may be curved slightly to enhance the overall appearance of the boat. The side walls of both sections are constructed with a step offset including a substantially horizontal inwardly directed portion and a downwardly extending portion 42 which joins the bottom wall, as best seen in FIG. 3. The top edges of the front and side walls are stiffened by an overhanging lip which extends around the full perimeter of the front section, but which in the back wall of the rear section is interrupted by a wooden transom 44 that can be used for either mounting a small outboard engine (not shown) or a rudder. See FIG. 7.

As best seen in FIG. 4, each of the hull sections is preferably constructed from a pair of vacuum molded inner and outer

plastic shells

43 and 45 which are joined together by a lap joint around the outer periphery, as indicated at 46. The space between the inner and outer shell is filled with a rigid or a semi-rigid foam plastic to add strength and rigidity shown in FIG. 4. In addition, wood or plastic reinforcing stringers may be inserted between the two shells around the top, as indicated at 47, to give added rigidity and strength to the hull sections. The rear hull section 14 is shaped so as to nest inside the front hull section when the boat is disassembled to provide compact storage. As further seen in FIG. 4, the inner shell of the rear section is further shaped to provide a raised seating area, as indicated at The two

hull sections

12 and 14 are supported by and at the same time provide a rigid connection between a pair of inflatable pontoons and 52, which are shown 3 in their assembled and inflated condition in FIGS. 1, 2, and 3. Each pontoon is constructed from four longitudinal strips of rubberized fabric. The four strips are shown in FIG. 6 after they are cut and laid out in a single plane. The two strips forming the top two quarters of the pontoon are indicated at 54 and 56. The strips forming the bottom two quarters of the pontoon are indicated at 58 and 60. As best seen in FIG. 6, the

top strips

54 and 56 have a pair of straight edges and a pair of edges which are curved at either end to intersect the straight edges. The bottom two strips are similarly formed with a straight edge and an edge which is curved at either end to intercept this straight edge. The pontoon is formed by joining the straight edges of the top two

strips

54 and 56 together, the straight edge of the strip 6 is joined to the curved edge of the strip 56 and the straight edge of the strip 58 is joined to the curved edge of the strip 54. Finally, the curved edges of the strip 60 and 58 are joined to each other to provide. when inflated, a substantially cylindrical shaped pontoon which terminates at a point at either end. As best seen in FIG. 2, the top of the pontoon lies in a common horizontal tangential plane out to the ends of the pontoon while the bottom of the pontoon curves upwardly at either end. The rear end may be rounded off more than the front end of the pontoon to provide an improved appearance. The edges of the strips may be joined together by conventional techniques preferably utilizing reinforcing tape, such as indicated at 62, to overlap the seams. While the pontoon can end in conventional conical tips closed by plugs or end caps, an improved construction is realized when, as best shown at the rear in FIGS. 1 and 2, substantially spherical end shapes are formed by modifying the shapes of the tips of the four panels. The ends can then be covered by flat sealing patches, or the reinforcing tape 62 may be continued across the ends, thus eliminating the complexity and potential structural weakness and leakage around end caps or plugs. This system permits a pontoon shape which is both visually graceful and efficient in the water.

Each pontoon is preferably divided into two separate airtight compartments by a conical shaped diaphragm 64 made of rubberized fabric and which is adjoined to the interior surface of the strips forming the pontoon around the periphery of the base of the conical dia phragm. Suitable valves 66 and 68 are provided in each pontoon on either side of the conical diaphragm 64 through which air can be pumped into the pontoon to inflate it or through which air can be released from the pontoon to deflate it.

The manner in which the pontoons are joined to the hull sections is best seen by referring to FIG. 4. Each of the hull sections has its outer shell molded around an extruded aluminum or plastic tube 70, the tube 70 being provided with a longitudinal slit 72. The tube 70 preferably runs the full fore and aft length of the hull section and is positioned at the juncture between the horizontal portion 40 and downwardly projecting portion 42 of the step offset. Each pontoon in turn is provided with a beading 74 running along a substantial length of the pontoon. The beading is preferably formed by a rope or solid plastic material which is joined to the pontoon by a webbing 76. The webbing is sewn or molded directly to the fabric of the pontoon.

When assembling the boat, the deflated pontoon is fastened to the hull sections by drawing the beading 74 through the tube 70, with the web 76 extending through the slit 72. Index markings may be provided on the pontoon for correctly positioning the hull sections longitudinally of each of the pontoons. When the pen toons are then inflated, they assume a substantially circular cross-sectional shape. However, the beading distorts the shape of the pontoon so that, as the air pressure is increased, the tension on the webbing 76 increases, thus firmly holding the pontoon against the horizontal and downwardly projecting

portions

40 and 42 of the hull section. This stressed connection between the pontoons and bull section prevents the pontoons from flexing sideways in normal use, giving the boat almost the same feel of rigidity and solidity of a boat of conventional rigid non-inflatable design.

The pontoons can be inflated from any suitable pump or other source of air. Preferably the pump should be one of high volume low pressure design, such as a bellows-type pump, since the inflated pressure need only be about a pound per square inch.

The embodiment shown in FIGS. 1-3 shows the two hull sections positioned in abutting relationship. An I- beam member 80 may be inserted between the two hull sections and pins, four of which are indicated at 82, may be inserted through the flanges and the projecting lips at the top of the hull sections. The lips of the two hull sections are arranged to fit snugly into the space between the flanges of the I-beam. This secures the two hull sections together in a semi-rigid configuration in which twisting of the two hull sections is resisted but a hinging motion is permitted to reduce stress as the boat rides over small waves. While the preferred embodiment is to have two hull sections joined together as indicated, the boat can be assembled using only one hull section, if desired, or may be arranged with the hull sections spaced apart. The space between the two hull sections can be bridged, for example, by a flat board that can be held in place by the pins 82. This board (not shown) can be used as a seat to increase the seating capacity of the boat.

When the boat is not in use, as heretofore indicated, the pontoons are deflated and folded by letting the air out of the pontoons and withdrawing the beading 74 from the tubes 70. The two hull sections are nested one inside the other and the deflated pontoons are folded and stored within the hull sections. The entire assembly can be easily mounted on top of an automobile roof in the manner shown in FIG. 5. After the pontoons and other paraphernalia are stored in the nested hull sections, a fabric cover 86 is used to hold the stored materials in place. The fabric cover is locked in position by snaps or other conventional means. The nested hull sections can then be mounted on the roof of an automobile using conventional suction cups 88 and straps 90 which clamp on the rain gutter of the automobile. Suitable holes may be provided through the reinforced rim or lip of the hull sections to permit anchor pins 92 on which are mounted the suction cups 88 to engage the hull sections and to hold the hull sections in place.

In addition to mounting a small outboard motor on the transom 44, the boat may be propelled by conventional oars. Holes 94 (see FIG. 1) are provided in the rim of each hull section for receiving conventional oarlocks.

In addition, as shown by FIG. 7, the boat may be operated as a sailboat. To this end a rudder 98 may be hingedly supported from the transom 44 and operated by a tiller 1%. A mast step and centerboard assembly is provided using welded steel-type sections as torque tubes. The centerboard and mast step assembly includes a first torque section 102 which is welded or otherwise secured to the l-beam 80. Additional crossbracing between the l-beam and the downwardly projecting torque section 102 may be provided to give lateral strength to the assembly. At the lower end of section 102 is welded a flat vertical plate 104 to which a centerboard 106 is pivotally secured by pin H08. A horizontal torque tube section 110 extends beneath the hull section l2 and is joined to a vertical tube section 112 which is adapted to receive a mast 114. The upper end of the tube 112 is provided with an integral plate 116 which is bolted to the reinforcing lip at the front of the hull section 12.

What is claimed is:

1. An inflatable boat comprising a pair of inflatable substantially cylindrical shaped pontoons of flexible material, rigid hull means including at least one unitary hull member having parallel sides extending in a fore and aft direction a distance substantially greater than the diameter of the pontoons, each side having an indented step extending the full length of the side, each forming an elongated aligning groove for receiving one of the pontoons, the two aligning grooves being parallel, radially extending webbing means secured to each of the pontoons along a substantial length thereof, and means releasably securing the webbing means to the hull means within the grooves, the radial extent of the webbing being sufficiently short to be put in tension by the inflation of the pontoons, wedging the inflated pontoons securely in the respective aligning grooves center of each of the indented steps, the beading sliding into the slots when the pontoons are deflated, the beading securing the webbing under tension by the inflation of the pontoons to hold the pontoons wedged in place in the grooves formed by the indented steps when the pontoons are inflated.

7. Apparatus of claim 6 wherein each pontoon when inflated is substantially cylindrical in cross-section over a substantial portion of its length, the inflated pontoons being deformed from the cylindrical shape by the tension of the beading and the wedging action of the indented steps.

8. A boat comprising a rigid unitary hull member formed with a pair of elongated V-shaped parallel steps extending the length of the hull on either side, each step having a narrow open-ended slit at the bottom of the V, a pair of elongated substantially cylindrical inflatable pontoons made of air-tight fabric, the V- shaped steps and associated slits extending longitudinally a distance substantially greater than the diameter of the pontoons, each pontoon including a longitudinal flexible webbing secured to the pontoon and extending radially thereof, the outer edge of the webbing having a beading, the webbing extending through said slits when the pontoons are in assembled position with the pontoons extending along the respective steps, the webbing being placed in tension between the beading and the pontoons when the associated pontoon is inflated within the confines of the V-shaped step.

9. The apparatus of claim 8 wherein said hull includes a plurality of separate sections positioned one behind the other, each section having steps which are formed by the indented steps to lock the pontoons in spaced apart parallel relationship.

2. Apparatus of claim 1 wherein the hull means includes two separate hull members positioned one behind the other in a fore and aft direction, each member having equally spaced parallel sides with the grooves of the two sections being aligned in a fore and aft direction.

3. Apparatus of claim 2 wherein the hull members are shaped such that one member can be nested inside the other section when the boat is disassembled.

4. Apparatus of claim 2 further including removable means for connecting the two hull members together, said means connecting the aft portion of the forward hull member to the forward portion of the aft hull member at a position substantially the horizontal plane above the tangent to the top of the two pontoons.

5. Apparatus of claim 2 wherein each hull member includes an inner and outer molded shell forming a double-walled structure, and plastic foam material filling the space between the shells, each hull member being buoyant in water when fully loaded independently of the pontoons.

6. Apparatus of claim 1 wherein said means for securing the webbing to the hull means includes a beading attached to each pontoon and extending lengthwise of the pontoon, the hull means having a longitudinal slot positioned on the outside of the hull means at the aligned with the steps of the adjacent section, whereby the sections are held in alignment by the pontoons engaging the aligned steps.

10. A boat comprising a rigid frame, a pair of inflatable substantially cylindrical pontoons made of fabric, and means detachably connecting the pontoons to the frame in spaced apart parallel relationship, said means including a radially extending webbing secured to and extending longitudinally of each pontoon, the frame including means on either side of the frame forming a pair of surfaces extending in a fore and aft direction of the boat and engaging an inflated pontoon tangentially at accurately spaced positions on either side of the associated webbing, and means attached to the frame for holding the webbing in tension when the associated pontoon is inflated to urge the pontoon against said pair of tangential surfaces.

11. Apparatus of claim 10 wherein said means for means securing the webbing against being withdrawn from the slot in a transverse direction while permitting movement of the webbing longitudinally of the passage.

l2. Apparatus of claim 10 wherein the frame includes an open box-shaped hull that is floatable independently of the pontoons, thepontoons when inflated supporting said hull above the water.

Claims

1. An inflatable boat comprising a pair of inflatable substantially cylindrical shaped pontoons of flexible material, rigid hull means including at least one unitary hull member having parallel sides extending in a fore and aft direction a distance substantially greater than the diameter of the pontoons, each side having an indented step extending the full length of the side, each forming an elongated aligning groove for receiving one of the pontoons, the two aligning grooves being parallel, radially extending webbing means secured to each of the pontoons along a substantial length thereof, and means releasably securing the webbing means to the hull meaNs within the grooves, the radial extent of the webbing being sufficiently short to be put in tension by the inflation of the pontoons, wedging the inflated pontoons securely in the respective aligning grooves formed by the indented steps to lock the pontoons in spaced apart parallel relationship.

6. Apparatus of claim 1 wherein said means for securing the webbing to the hull means includes a beading attached to each pontoon and extending lengthwise of the pontoon, the hull means having a longitudinal slot positioned on the outside of the hull means at the center of each of the indented steps, the beading sliding into the slots when the pontoons are deflated, the beading securing the webbing under tension by the inflation of the pontoons to hold the pontoons wedged in place in the grooves formed by the indented steps when the pontoons are inflated.

8. A boat comprising a rigid unitary hull member formed with a pair of elongated V-shaped parallel steps extending the length of the hull on either side, each step having a narrow open-ended slit at the bottom of the V, a pair of elongated substantially cylindrical inflatable pontoons made of air-tight fabric, the V-shaped steps and associated slits extending longitudinally a distance substantially greater than the diameter of the pontoons, each pontoon including a longitudinal flexible webbing secured to the pontoon and extending radially thereof, the outer edge of the webbing having a beading, the webbing extending through said slits when the pontoons are in assembled position with the pontoons extending along the respective steps, the webbing being placed in tension between the beading and the pontoons when the associated pontoon is inflated within the confines of the V-shaped step.

9. The apparatus of claim 8 wherein said hull includes a plurality of separate sections positioned one behind the other, each section having steps which are aligned with the steps of the adjacent section, whereby the sections are held in alignment by the pontoons engaging the aligned steps.

11. Apparatus of claim 10 wherein said means for holding the webbing includes means on either side of the frame forming a pair of tubular passages extending in a fore and aft direction a distance substantially greater than the diameter of the pontoons, each of the passages having a slot for receiving the webbing, and means securing the webbing against being withdrawn from the slot in a transverse direction while permitting movement of the webbing longitudinally of the passage.

12. Apparatus of claim 10 wherein the frame includes an open box-shaped hull that is floatable independently of the pontoons, the pontoons when inflated supporting said hull above the water.