US3450084A

US3450084A - Boat hull construction with outrigger pontoon assembly

Info

Publication number: US3450084A
Application number: US630629A
Authority: US
Inventors: Fred Gerbracht
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-04-13
Filing date: 1967-04-13
Publication date: 1969-06-17
Anticipated expiration: 1986-06-17

Description

June 17, 1969 F. GERBRACHT 3,450,084

BOAT HULL CONSTRUCTION WITH OUTRIGGER PONTOON ASSEMBLY Filed April 13, 1967 Sheet Z Of 3 Q n 5 w Q o. \1 v -S Q l Q N v N 0o S N a n a al Q 1 n,

0 o| Q I I jl 0 `0| @g N q, sa fr Q Q v t "S v \`7 J .n v 0 Lk (NX 0 om, Fred Gerbrac/:

INVENTOR.

Hlll June 17, 1969` F. GERBRACHT 3,450,084v

BOAT HULL CONSTRUCTION WITH OUTRIGGER PONTOON ASSEMBLY United States Patent O 3,450,084 BOAT HULL CONSTRUCTIN WITH OUTRIGGER PONTOGN ASSEMBLY Fred Gerbracht, 2325 Seidenberg Ave., Key West, Fla. 33040 Filed Apr. 13, 1967, Ser. No. 630,629 Int. Cl. B631) 1/10 U.S. Cl. 114-665 7 Claims ABSTRACT F THE DISCLOSURE The present invention generally relates to improved and novel structure in boat construction generally in the form of a runabout hull having a novel cooperative relation with removable Outrigger pontoons.

As is well known, boating for pleasure, fishing, cruising and when in engagement in various water sports is becoming increasingly popular. Boats generally are constructed in a manner which renders them highly efficient for a specialized purpose while being unacceptable for other purposes. For example, a boat which is adapted especially for fishing or skin diving would be relatively inefficient for use for towing water skiers.

Attention is directed to my prior U.S. Patent No. 3,061,- 845 and other prior art for recitation of the advantages offered by catamaran-type boats. It is therefore, one object of this invention to provide a boat hull construction which may be combined with Outrigger pontoons to provide a catamaran-type of boat or employed without the Outrigger pontoons so that the hull may be used for runabout service. The hull is substantially parallelopiped in form thereby eliminating the single conventional pointed bow that rides high in the air rather than in the water and is primarily for the purpose of maintaining the traditional image of a boat. With my construction and with given over-all dimensions, considerably more usable space is available than would be found in a like-size conventional hull bounded by curved surfaces. The specic construction of the boat hull of this invention provides for substantially minimal but uniform freeboard for a given volume which renders it easy and safe for swimmers to enter the water and return to the boat without requiring the use of a boat ladder and also provides for a level decking, which taken with the floor or sole makes the entire area of the boat useful, or in other words, approximately doubles the useful area in comparison to conventional runabout design.

Another object of the present invention is to provide a boat hull which is strong but simply built and which depends upon two parallel longitudinal trusses positioned vertically in the sides of the hull so as to resist concentrated and reversing stresses that are created by alternatively hogging over a wave and then slamming down on the far side thereof and wallowing in the trough and also will resist similar stresses that occur when launching and retrieving the boat hull and trailing it over rough roads.

A further object of the present invention is to provide a boat hull construction consisting of two parallel longitudinal trusses positioned vertically in the sides of the hull Patented June 17, 1969 ICC which are joined to and interconnected by a plurality of transverse frames with the transverse frames being joined by employing longitudinal stringers with the entire hull being covered with an exterior skin to provide a strong, water-tight structure built from simply shaped and simply joined pieces, more numerous but shorter spanned then are found in a conventional hull and thus requiring less costly materials and less skilled labor in its manufacture.

Still another Object of the present invention is to provide a boat hull having a prismatic stern section with a narrow horizontal planing surface which is quite efficient for lightly loaded high speed operation with the horizontal planing surface being bounded on both sides by upwardly inclined planes which extend to the chines so that with heavier loading, the hull assumes an increasing V-bottom characteristics, namely, an ability to plow through lrough water with a heavy load with quasiplaning dynamics and without excessive pounding. The forward end of the hull is a complexly curved section at least two sharply pointed bows that will cut into low waves and in combination with the Outriggers will breast a higher wave, to disperse the water, generate spray, utilize some of the spray to decrease skin resistance and reduce the impact of the water against the underbody and insure smoother and faster passage of the hull.

Still a further object of the invention is to provide a boat hull having Outrigger pontoons thereon including the provision of support arms to position the Outrigger pontoons in parallel spaced relationship to the center hull. The support arms cooperate with transverse frames or trusses to transmit stresses thereto in which the position of the Outrigger pontoons may be adjusted and also Oriented in an operative position or folded into a vertically extending position to reduce the Over-all width of the boat. The Outrigger pontoons are specifically shaped and Oriented in -relation to the center hull to generate dynamic lift and thrust to counteract the plunging and yawing effect produced on the craft by driving a pontoon into a wave. To reduce the sudden increase in drag when a pontoon is submerging, the cross-section of the bow portion is made triangular with the vertex downward so that buoyant lift increases about twice as fast as f-rictional drag with the bottom surface widening aft to form a horizontal planing surface that terminates in a step slightly forwardly and above the transom chine of the center hull to make auxiliary planing and stabilizing sponsons that become more effective as load increases and the sea gets rougher. By extending the pontoon -rearwardly of the transom and by rounding the stern end of the pontoons upwardly, the pontoon will provide dynamic and buoyant lift when overtaken by a following sea. Basically, the Outriggers add dynamic lift and stability at planing speeds, add buoyancy for heavier loading and serves to initiate a quick, easy roll away from the sea regardless of the direction the wave approaches the craft.

These together with other Objects and advantages which will become subsequently apparent reside in the details Of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective view with decking removed illustrating the boat hull construction and Outrigger pontoons associated therewith;

FIGURE 2 is a perspective View with exterior skin thereof -removed to illustrate the structure thereof;

FIGURE 3 is a `fragmental perspective view taken from under the bow end of the boat hull;

FIGURE 4 is a longitudinal, sectional view taken substantially upon a plane passing along section line 4*4 of 3 FIGURE 1 illustrating further specific structural details of the boat hull;

FIGURE 5 is an end view from the stern illustrating the outrigger pontoons disposed in inoperative relation;

FIGURE 6 is a detailed plan view of the mounting structure for one of the outriger pontoon supporting arms;

FIGURE 7 is a longitudinal, sectional View taken substantially upon a plane passing along section line 7-7 of FIGURE 6 illustrating the further structural details thereof;

FIGURE 8 is a plan view of one of the outrigger pontoons; and

FIGURE 9 is a diagrammatic view showing the transverse configuration of the pontoons at the various stations.

Referring now specifically to the drawings the boat hull construction of the present invention is generally designated by the numeral 10 and a pair of Outrigger pontoons, each being substantially identical in construction, are designated by reference numeral 12 with the pontoons being disposed in substantially horizontal spaced relation to the side surfaces of the boat hull 10.

Referring specifically to FIGURE 2, the boat hull includes basically two parallel longitudinal trusses 14 and 16 which are vertically disposed and longitudinally elongated and may be considered separated into panels with panel points being generally designated in FIGURE 2 at 18, 20, 22, 24 and 26. The composition of the trusses or box beams may vary provided that the materials chosen provide strength adequate to cope with the stresses encountered in use with each truss including a top chord member 28 and a bottom chord 30. The truss may be strengthened by crossed bracing as at 32 which may be provided between some of the panel points or between all of the panel points thus providing strength and rigidity to the longitudinal trusses 14 and 16.

At the tive panel points 18-26, live transverse trusses, frame members or

bulkheads

34, 36, 38, 40 and 42 are xedly attached with knees or gussets 44 provided whereever desired and reinforcement members 46 are provided for sustaining the supporting structure for the Outrigger pontoons 12 in a manner described hereinafter.

The rearmost transverse truss 34 is constructed to provide for mounting an outboard motor (not shown) thereon with a cut-out 48 being provided in the top edge thereof. It is pointed out that other types of propulsion may be employed for the boat as desired. The

transverse trusses

38 and 40 are also provided with

recesses

50 and 52 to provide a passageway along the center line of the hull 10. As illustrated in FIGURE 2, the

trusses

34, 36, 38 and 40 have

bottom chords

54, 56, 58 and 60 and the bridging of the three spans between the bottom chords is accomplished with longitudinal stringers as at 62 with the stringers being disposed in pairs yon opposite sides of the center line of the hull with the skin engaging the bottom of the stringers and the iioor or sole engaging the top surface thereof. A central area of the hull may be left free of stringers to provide for a glass viewing port, a live well or a beverage cooler.

The underside of the hull defined generally by the bottom surface of the stringers 62 and the bottom surfaces of the chords 54, S6, 58 and 60 is substantially planar and is designated by the numeral 64 and an upwardly inclined segment 66 is disposed along one side of the planar surface 64 and a similar upwardly inclined segment 68 is disposed along the other side thereof. The

hull segments

64, 66 and 68 may be fabricated from any readily available planar material such as laminated material including marine plywood or equivalent material.

While a flat bottom hull planes efficiently, its action becomes quite rough in a rising sea so a bow section generally designated by the numeral 70 is provided forwardly of the

planar segments

64, 66 and 68. The bow section 70 is a complexly curved structure which may be constructed of fiber reinforced .plastic or other moldable material and which is iixedly adhered by bolts, rivets, cement or the 'like between the forward portions of the longitudinal trusses 14 and 16 and likewise adhered to transverse truss 40 and the

planar segments

64, 66 and 68. The bow section 70 is provided with a concave central area 72 which extends between a pair of

parallel bows

74 and 76 which bows are relatively sharp and deep and carried forward to a point 78 and then rise sharply to merge with the leading edge 80 of the bow section 70.

Thus, when the hull is making headway there is formed somewhat of a funnel-shaped cavity between the

bows

74 and 76, concavity 72 and the surface of the water. The

bows

74 and 76 form a spray which entrains air and more or less compresses this air and spray mixture as the hull moves forward. While this function is known in socalled gull wing hulls and single hull catamar'ans, this structure provides the Iadditional feature in that the dynamic compression just described is suddenly relieved by a transversely disposed step 82 which allows considerable expansion of the entrapped air under the forward part of planar segments 64. As is well known, in a planing hull, much of the shock originates where a line across the bottom near the forward edge of the planing surface first strikes the water and the upward dynamic force that supports the boat, imparting a downward velocity to that water, instantaneously increases from zero to some finite value. However, in this construction, air is first entrained and compressed, then released into this area where upward thrust is instantaneously applied, and air being a compressible medium, absorbs more of the initial shock in this hull than in any other planing hull configuration thus far proposed. Depending on the characteristics desired

bows

74 and 76 can be made sharper and deeper and can be continued aft by fastening keelsons to the stern sections of the hull if desired.

While the longitudinal trusses in FIGURE 2 are il.

lustrated as open frameworks, in FIGURE 1, the longitudinal trusses are illustrated as solid bodies with it being pointed out that the trusses are either filled with buoyant material such as foam plastic or covered with an impermeable membrane such as plywood or fiber reinforced plastic thus defining side surfaces 84 to complete the hull.

By providing buoyant bodies, a righting moment will be exerted in case of swamping and rolling thus resist- -ing capsize until the hull has been rolled substantially to perpendicular relation to the water surface, Also, as illustrated in FIGURE 4, sole or floor panels 86 have been provided between the

transverse trusses

34, 36, 38, 40 and 42 and in the interest lof safety the space between the sole 86 and the

bottom segments

64, 66 and 68 should be sealed or preferably filled with buoyant material.

As illustrated specifically in FIGURES 6 land 7, mounting structures or sockets 88 are provided for each of the supporting arms or struts 90 for the pontoons 12 and which also form part Iof the joint between the longitudinal trusses 14 and 16 and the

transverse trusses

34 and 42 whereby the resistance to vertical as well as longitudinal flexure that is developed by the framework of the center hull is imparted to the struts or arms 90 to engage similar socket means incorporated in and forming part of the framework of the pontoons 12. The pontoons are light in weight and are filled or covered to insure their buoyancy -so that a stress inflicted by the sea is dissipated through the center hull and both pontoons, fore and aft, which greatly improves the riding qualities of the craft. The stern sockets l88 also strengthen the transverse frame or truss 34 which forms the transom to better withstand either an youtboard motor o1' other propulsion system such as an in-board-outboard drive and with four sockets serving to strengthen and rigidity the hull at both the bow and stern areas.

As illustrated each of the pontoons 12 includes an elongated 'buoyant body 92 having relatively slim -bows 94 which are disposed ahead of and well outboard of the center hull to provide leverage so that when one of them strikes a wave, a quick, easy pitch and roll is started rather than the dead, sudden movement characteristic of a single hull in a heavy sea. Likewise, when a pontoon crosses the crest of a wave, it will start a downward movement soon enough to avoid the rending crash noted in the action of many boats, and will itself receive and -distribute the rst shock of the downward pitch. FIGURE 4 illustrates the relationship of the lengths of the pontoon to the center hull and the stern end 96 of the pontoon body 92 is broad and rather voluminous and the bottom surf-ace of the stern end 96 of the pontoon body 12 is downwardly and forwardly curved as at 98 to impart lift when `overtaken by a following sea. This lift force is leveraged by the distance aft and `outboard from the center of gravity of craft and starts a quick and easy roll and lessens the chance that a wave will break over the transom top edges surface 48 of the hull.

The struts or arms 90 are in the form of hollow or tubular members having edge anges and which are generally rectangular in section and are connected to the inboard surface of the pontoon body 92 by a socket structure 100 similar to sockets `88 but somewhat lighter in construction to cope with the lesser forces encountered by the outboard end.

If desired, the space between the hull and the pontoons 12 be closed with fabric material to reduce spray otherwise -thrown into the center hull or a net may be rigged for the benefit of personnel or gear to prevent such gear or personnel from falling `overboard from the boat hull. Holes or hardware may be provided in the pontoon 12 for ldocking and the at top surface of the pontoon body 92 is useful for boarding the craft or t0 move around the center hull in lieu of the side decks. Also, one pontoon 12 may be removed and the struts or arms 90 may be used to tie up beneath the edge of a pier or the craft may be employed with a single Outrigger thus introducing the useful features and versatility of the pontoon structure.

The

socket structure

88 or 100 is in the form of a boxlike enclosure of plates 104 welded or Votherwise permanently lixed to each other and xed to the reinforcement 46 and to the corresponding

transverse truss

34 or 42. The

sockets

88 and 100 must be sufficiently strong to transmit forces directly and effectively to the transverse trusses in particular and to the hull framework in general.

A transversely extending solid pin 106 extends through the box-like socket 104 and extends through a tubular sleeve 108 that is fixed horizontally through the end of the strut or arm 90 with both of its extremities protruding as illustrated in FIGURE 6.

The strut 90 is restricted in regard to its upward and downward llexure by means of tubular stops 110 which may be cylindrical or any other shape and each stop 110 is provided with an inserted rubber snubber 112 which is exposed through a cutaway or slotted portion 114 of the stop 110.

The rubber snubbers 112 are disposed in opposed facing relation and engage the outer inclined surface of oppositely disposed wedges 116 which are clamped to the top and bottom surfaces of the strut or arm 9'0 by means of a through lbolt 118 extending through the strut or arm 90 and extending through a longitudinal slot 120 in each of the wedges 116. As illustrated, the center part of the wedges has the exterior surface thereof hollowed out as at 122 to enable the head and nut of the bolt 11.8 to engage flat parallel surfaces thus enabling the wedges to slide longitudinally in relation to the strut 90 and -by selectively sliding the wedges 116 and clamping them in position, the range of upward or downward movement of the strut 90 may be adjusted so that the position of the struts 90 may be varied with the rubber snubbers allowing resilient limited movement of the struts even after they have been positioned by selective movement of the wedges 116. If desired, an elastic boot to exclude water, together with a water-tight bottom and a drain hole may be provided to combat corrosion.

By retracting pin 106 and removing it, the strut 90 can be withdrawn completely outwardly and pivoted and when forced back into the socket it will assume its established position. Since the optimum position depends on loading, roughness or water, and desired speed f-or economy, it will be necessary to -be able to duplicate `a previously determined position.

When it is desired to rotate the pontoons 12, for instance to rotate them upward and inward and secure them over the top of the craft :as illustrated in FIGURE 5 in order to trail it on the highway, pin 106- is withdrawn at both ends of the pontoon and the struts 90 are pulled out until the protruding ends of the sleeve 108 are retained by the inturned ears 124 which prevent the structure from falling to pieces after the pins 106 are withdrawn and the operator is manipulating the pontoons into the desired position. The pin 106 is then inserted through the sleeve 108 and the holes 126 to enable the struts 92 to swing upwardly to a vertical position as illustrated in FIGURE 5. The pontoons y12 may swing into overlying and supported relation to a superstructure or cabin generally designated by the numeral 128 or any suitable interconnecting structure may be provided to retain the pontoons in the inoperative position during over-the-road transport. The upper surface of the lips 124 have a notch to enable complete removal of the inner ends of the struts 90 from the sockets 88 when it is desired to completely remove the pontoons as for transport resting directly on the center hull.

FIGURES l, 4, 8 yand 9 illustrate the starboard pontoon and in FIGURES 8 and 9, station numbers are assigned for reference between the vertical and horizontal projections and the cross-section with the structure being approximately a typical configuration for a 26-foot pontoon for use with a 17-foot center hull and is not to be construed as limiting the invention. It is pointed out that the other pontoon or port pontoon is related by bi-planar symmetry, or in other words, in a transverse section is a mirror image of the corresponding section in the other pontoon.

The bow 130 -at station 0 is narrow and sharp to literally cut the water with a minimum of shock but abruptly deepens to provide for an internal structure sufliciently resistant to serve for anchoring, docking or beaching with the keel portionl 132 of the forward end of the pontoon being reinforced to resist abrasion. The keel continues narrow to about station 6 but the top of the pontoon widens to produce a concave flaring section ,as at 134 which has the novel and specific function of lifting and thrusting to the left as it is driven into a wave thus counteracting the tendency to bury itself downward and pull to the right when considering the pontoon in FGURE 8 which is a starboard pontoon. Moreover, this tendency is lessened in this invention by a cross-sectional shape of bow portion, which is a soalene triangle with the vertex downward as most clearly seen at station 6'. This crosssection is one whose buoyancy increases about twice as fast as its skin `friction or drag increases upon being submerged, thus cooperating with the flaring surface just described, both factors acting well -ahead of the center of resistance of the whole craft to minimize yawing and pitching in rough water.

The chine line 136 departs from the inboard butt plane and merges with the widest portion of the pontoon around station 21', or stated differently, the bottom of the pont-oon widens to its maximum ahead of the step 138 to make a planing surface that cooperates with the planing surface of the main hull, thus increasing its load carrying ability and providing increased lift with increased sub- 7 mergence, thereby tending to keep the craft on an even keel.

The stern end surface ,140 is relatively broad and blunt and `forward `from station 26' abruptly deepens in a short radius curve as at 98 to provide dynamic lift and form a buoyant stern section aft of station 21 which will rise quickly when overtaken by a following sea. For clarity, stations 21 and 26' are shown in FIGURE 10 to the left of the inner surface in order to illustrate the step or abrupt change 'at 211'.

What is claimed as new is as follows:

1. A boat hull comprising two longitudinal trusses disposed in parallel spaced relationship with their minor axes vertical, and a plurality of transverse trusses whose minor faxes are vertical being rigidly joined with the longitudinal trusses, and an impermeable covering fixed to the bow, stern, side and bottom surfaces of the trusses to define a Water borne hull thus leaving the top of the hull open throughout its area, said longitudinal trusses having a depth substantially equal to the depth of the hull throughout their length, at least two of the transverse trusses having a depth substantially equal to the depth of the hull throughout their length, said transverse trusses having the lower chords thereof bridged by a plurality of longitudinal stringers, said covering including planar segments and a complexly curved bow section fixedly positioned between the forward ends of the longitudinal trusses and a step extending completely transversely of the hull of the juncture between the bow section and planar segments, said bow section including at least two parallel bows deeper than the planar segments with a concave area between the bows with the concavity diminishing in crosssection aft and terminating at said step, said bows terminating in forward points disposed 'below the surface of the bow section with the forward edge of each bow extending vertically upwardly to merge with the leading edge of the bow section.

2. The structure as defined in claim 1 together With at least one Outrigger pontoon disposed in space parallel relation to the water borne boat hull, a pair of spaced parallel struts interconnecting the pontoon and the boat hull, and means interconnecting the strut and the boat hull to enable adjustment of the struts in a vertical plane to position the pontoons in a desired position to stabilize the hull and to enable the struts to swing vertically to Ian inoperative vertical position for orientation of the pontoons within the confines of the hull and vertically above the side portions thereof.

3. The structure as defined in claim 2 wherein said means connecting the struts to the hull includes resilient means to cushion flexing movement of the struts in relation to the hull.

4. A boat hull comprising two longitudinal trusses disposed in parallel spaced relationship with their minor axes vertical, and a plurality of transverse trusses whose minor axes are vertical being rigidly joined with the longitudinal trusses, and an impermeable covering fixed to the bow, stern, side and bottom surfaces of the trusses to define a hull, at least one Outrigger pontoon disposed in spaced parallel relation to the boat hull, a pair of struts interconnecting the pontoon and the boat hull, and means interconnecting the strut and the boat hull to enable adjustment of the struts in a vertical plane to position the pontoons in a desired position and to enable the struts to swing vertically to an inoperative vertical position for orientation of the pontoons within the confines of the hull and vertically above the side portions thereof, said means connecting the struts to the hull including resilient means to cushion iiexing movement of the struts in relation to the hull, said means connecting the struts to the hull including wedge means for adjusting the position of the struts in relation to the hull.

5. The structure as defined in claim 4 wherein said struts being disposed approximately one-half beam from the hull with the front end of the Outrigger being one-half beam ahead of the hull and the stern end of the Outrigger one-half beam -astern of the hull, said means connecting the struts to the hull being disposed adjacent the transverse trusses.

6. The structure as defined in claim 4 wherein said Outrigger includes an elongated buoyant body having a pointed forward end, the top and inner surface of said body being Substantially planar, the outer surface of said body converging forwardly toward the inner surface, the bottom surface of said body converging forwardly towards the top surface thereof, the rear end of said body being substantially planar and blunt, the forward portion of the outer surface of the body being concave to produce an inward lateral force on the body when entering water to counteract the tendency of the front end of an Outrigger to be forced laterally away from a boat hull when entering water.

7. The structure as defined in claim 61wherein the lower surface of the body curves upwardly to define the lower edge of the concave portion of the outer surface of the body, the top surface of said body aligned with the concave portion of the outer surface being wider than the corresponding bottom surface, said bottom surface of the body being provided with an upwardly offset step in adjacent but spaced relation to the blunt rear end thereof to define a planting surface, the bottom surface of the body curving upwardly from the strut to the blunt rear end to provide a lift from an overtaking following sea.

References Cited UNITED STATES PATENTS 2,392,834 1/ 1946 Clement 9-6 2,855,885 10/1958 Thomas 114-43 3,051,115 8/1962 Canazzi i 114--56 3,075,488 1/1963 Wolfe et al. 114-665 3,148,652 9/ 1964 Canazzi 114-665 3,225,729 12/ 1965 Ewing 114-665 3,316,873 5/ 1967 Dismukes 114-61 FOREIGN PATENTS 550,193 12/1957 Canada.

1,025,312 1/ 1953 France.

529,629 11/ 1940 Great Britain MILTON BUCHLER, Primary Examiner.

RICHARD A. DORNON, Assistant Examiner.

U.S. Cl. X.R. 9-6; 114-5, 6l