US3024478A

US3024478A - Hard-chine boat

Info

Publication number: US3024478A
Application number: US753850A
Authority: US
Inventors: Plum John
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-08-07
Filing date: 1958-08-07
Publication date: 1962-03-13
Anticipated expiration: 1979-03-13

Description

March 13, 1962 6 Sheets-Sheet 1 Filed Aug. 7, 1958 INVENTOR JOHN PLUM A3 1. QM MW ATTORNEY March 13, 1962 J. PLUM 3,024,478

HARD-CHINE BOAT Filed Aug. 7, 1958 6 Sheets-Sheet 2 INVENTOR r 14 w JOHN PLUM:

BY 1 ATTORNEY March 13, 1962 J. PLUM HARD-CHINE BOAT 6 Sheets-Sheet 3 Filed Aug. 7, 1958 INVENTOR JOHN PLUM ATTORNEY March 13, 1962 J. PLUM 3,024,478

HARD-CHINE BOAT Filed Aug. 7, 1958 6 Sheets-Sheet 4 I\\ 12' 92 IX 72 1 82) f go W 72 I i l J60 6O I 1 l 5 l i 90 so 82 as 80 I l i w! 63 1 1 Q x 4 I I s 8 s2 58 32 92 4 m 30 INVENTOR JOHN PLUM ATTORNEY March 13, 1962 J. PLUM HARD-CHINE BOAT 6 Sheets-Sheet 5 Filed Aug. '7, 1958 INVENTOR' JOHN PLUM B A zk m/ ATTORNEY March 13, 1962 J. PLUM HARD-CHINE BOAT 6 Sheets-Sheet 6 Filed Aug. 7, 1958 INVENTOR JOHN PLUM ATTORNEY 3,024,478 HARD-CHINE BOAT John Plum, 1611 Connecticut Ave. NW., Washington, D.C. Filed Aug. 7, 1958, Ser. No. 753,859 18 Claims. (Cl. 9-6) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to a high-speed, hard-chine boat, and more particularly to the combination of a metal framework in a wooden hull of the hard-chine type.

The choice of a hard-chine planing hull, over a roundbottom boat of like size and power, is dictated where it is desired to increase both the speed of the hull and its load carrying ability inasmuch as a hard-chine hull possesses the quality of producing dynamic lift which at high speeds results in a considerable reduction in resistance. In fact, a change from round-bottom hull lines to hard-chine lines may increase the obtainable speed of a given hull from 30 knots to 38 knots. Unfortunately, the ability of a hard-chine boat to produced dynamic lift, which is necessary for speeds higher than, say 30 knots, may also produce violent hull accelerations in rough Weather. Since the dynamic lift increases with the square of the speed, and since the bottom of the hard-chine boat is specifically designed to produce dynamic lift, the impact loads will increase many fold, while the transverse strength obtained from the round-bottom skin has been practically eliminated by the change to a hard-chine hull. The planking in a round-bottom boat makes a large contribution to the transverse strength of the arch-shaped sections of a round-bottom boat. However, the shape of the sections of a hard-chine boat is such that the skin contributes little to the transverse strength, and therefore attention must be focused to a greater extent on the frames, which is one of the objects of this invention.

In accordance with conventional practice, a wooden hull, hard-chine boat is constructed with a wooden skin, the sides and bottom of which are screwed and/or glued together at their points of juncture. A chine strip is generally aflixed to the interior of the hull to the sides and bottom along the line of connection between the respective sides and the bottom, each of said strips being glued and bolted to the respective sides and bottom. The chine strip serves as one of the primary members to resisting flexing between the side and bottom panels.

In addition, the prior art practice has generally been to use wooden frames and a wooden center-line girder extending longitudinally of the hull. The respective frame members are glued and bolted to the sides and bottom of the boat as well as to the longitudinal center line girder, said connections of the frame members to the sides, bottom and the center line girder being relatively flexible in spite of diligent and skilled labor used, due to the inherent flexible nature of wood frame members and glued and bolted joints.

Since the high pressure area for the impact of a wave on the bottom of a hard-chine boat is comparatively small, the mass of the hull is suddenly lifted by a force applied on an area which extnds over only a limited number of frames. Inasmuch as the hull weight cannot safe- 1y be accelerated by these few frames, it is important that the dynamic lift from the wave impact be transmitted fore and aft to as many frames as possible. In the prior art structure described above it has been found that the wave impact is transmitted to at best a very limited number of frames and it is an object of this in- 3,024,478 Patented Mar. 13, 1962 mln Where f is the hydrodynamic force on the hull bottom w is the weight that is accelerated a is the resulting acceleration in feet per second squared g is the acceleration due to gravity (32.2 feet per second The significance of this relationship can be illustrated by example. Assume that a 20 ton boat strikes a partic-\ ular wave at a speed and attitude that produce a hydrodynamic impact force of 30 tons. If the entire mass of the hull is effectively accelerated, as is the case with the instant invention, the resulting acceleration will be:

If we assume however, as a simplified case, that this same hull has such a degree of longitudinal and transverse flexibility, as is the case with the prior art construction,

that the 30 ton impact force initially accelerated only one fourth of the mass of the hull, the acceleration of the affected portion would be:

Accordingly, the acceleration experienced by an occupant carried above the impact area of a flexible prior art hull structure would be four times that experienced in the rigid structure of the instant invention.

The hull structure should therefore, transmit the whole mass of the hull weight rigidly onto the planing surface so that the entire hull weight contributes to the mass which must be accelerated by the impact force. It is obvious that if only that part of the hull adjacent to the impact area is initially accelerated, the movement of the skin during the bending of the hull will put a great strain on all the joints, especially along the hard chine which is reluctant to participate in any longitudinal flexibility.

One of the prime disadvantages of the prior art flexible hard-chine boat construction is that the flexing of the hull brings about loosening of the connections between the frame members and the hull, and center line girders respectively, thereby materially weakening the hull structure and ultimately causing hull failure.

In the prior art boat structure the greater part of the stiffness of the hull is provided by high sides, rather than by the structure along the center line of the hull. Because the chine structure is more reluctant to flex than the structure along the center of the hull, almost all of the hull weight is, at least at the very beginning of a hull acceleration, transmitted to the ends of the frames, while the high pressure caused by a. wave impact will usually be near the center of the hull. In other words, the downward reaction force is transmitted to the ends of the frames, while the upward acceleration force is near the center. These forces combine to push the center of the bottom upward in respect to the sides, that is, they tend to flatten out the dead-rise angle of the planing surface. In a conventional boat a change of dead-rise, or panting" produces an extreme strain on all joints between the hull skin and wooden frame members, and is particularly the arch enemy of all hard chine structures inasmuch as it results in a tendency for the bottom of a hard chine boat to flex relative to the sides thereof, thereby causing substantial bending motion at the chine with a resultant weakening of the fastenings at the chine and ultimate fracture thereat. A further disadvantage of the prior art boats is that the Wooden center line girders generally used are not only lacking in longitudinal strength but are also lacking in lateral stiffness and therefore fail to distribute unbalanced wave impact loads fore and aft to neighboring frame members.

A further shortcoming of an all-wooden boat construction is the difficulty involved in joining wooden frames to a wooden girder. Each of these many joints should, of course, be as strong as the frame itself. However, the fitting of a good glue joint requires skill and patience which is not always available, while the Working area of a bolt in single shear is very small. Also the permanent set of wooden beams, as a result of unidirectional loads applied for an extended period, should be considered; this factor alone makes an all-wooden structure undesirable for high speed planing boats. From the day they are launched the hull lines of such boats are constantly changing, meaning that buttock slopes, dead-rise angle, shaft alignment and many other important parameters vary from their designed conditions. The effects of these changes on the performance of a conventional boat are undesirable to say the least; but in hulls designed, for instance, for hydrofoils, their effect may be most damaging to the boats performance. It is known that the interrelationship between the angles of the forward and aft foils is very critical and either a longitudinal flexibility or a permanent set of the whole structure will greatly influence the relative angles of the foils.

It is accordingly desirable that the frame structure of a boat be made of metal and the skin of wood, particularly since the skin of the hull requires a material that combines the characteristics of elasticity and great local strength, with the absence of galvanic action with shafts and propellers. Wood is therefore an acceptable material for the skin, especially since watertightness, elimination of water absorption, protection of fastenings, and cheapness of maintenance can be secured by an outside layer of fiberglass.

Insofar as prior art attempts to combine a metal framework with a wood hull structure are concerned, it is pointed out that such attempts have met with only slight success due to a failure to provide a satisfactory form of connection between the center line girder of the boat and the transverse frame members associated therewith. Furthermore, such prior art attempts have been complicated by failure to provide a satisfactory means for simplifying the frame construction so that the frame members may be satisfactorily fabricated at some point distant from the boat and then quickly and easily assembled Within the boat hull.

It is an object of this invention to overcome the aforementioned disadvantages inherent in the prior art.

Another object of the invention is to distribute the hull acceleration effect, of a wave impact force, over substantially the entire hull of a planing, hard chine boat.

A further object of the invention is to provide a hull structure in which impact forces are not transmitted through the chine.

An additional object of the invention is to eliminate the need for a longitudinal chine piece conventionally found on the interior of a hard chine boat.

An added object of the invention is to provide a novel and rigid framework and components thereof for a boat.

Still an added object of the invention is to provide a wooden hull, hard chine boat with a metal framework wherein the frame members and center line girder may be prefabricated outside of said hull.

Still a further object of the invention is to produce a metal framework for a wooden hull, hard chine boat wherein bottom frame members, side frame elements, and a center line girder are respectively connected to one another by means of fixed aligning or universal joints.

An additional object of the invention is to produce a wooden hull, hard-chine boat that is substantially free of change in dead-rise angle caused by a wave-impact force on the bottom thereof.

In accordance with the instant invention, a hard-chine boat is produced comprising a wooden-hull preferably made of plywood, and having a heat treated aluminum framework on the interior thereof and rigidly connected thereto. The hull comprises a pair of side panels and bottom panels, the respective sides being connected to the side edges of the bottom panels at the chine by means of layers of resin bonded fiber glass that overlap the joints between said respective sides and the bottom, and which are resin bonded to said wooden sides and bottom members thereby connecting said sides to said bottom panels. The two bottom panels are likewise joined together along the centerline of the boat in the same bonding manner. It is pointed out that the aforementioned fiberglass bonding technique eliminates the need for the conventional gluing and/ or bolting together of the parts of a boat hull; the instant technique also eliminates the need for the conventional chine-strip generally used on the interior of a hard-chine boat at the point of juncture between the respective sides and the bottom of said boat. In further pursuance of the objectives of this invention, the instant boat is provided with a heat treated aluminum framework mounted on the interior thereof and suitably bolted to the wooden skin of the hull. The frame Work comprises, a center-line-girder extending the length of the boat and attached to the bottom thereof, a plurality of transversely extending, parallel bottom-frame members extending from said girder toward the respective sides of the boat, and attached to said girder by means of a pair of universal joints hereinafter described in detail; in addition each bottom frame member is bolted to the bottom of the boat. The framework further comprises a plurality of vertical side-frame members bolted to the respective side panels of the boat, each of said side-frame members having its lowermost end attached to the outboard end of a bottom-frame member by a universal joint of the same type as that used to connect the respective bottom-frame members to the center-line girder.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood, by reference to the following detailed description when considered in connection with the accompanying drawings wherein;

FIG. 1 is a plan view of the hard-chine boat, produced in accordance with this invention, with the deck portion thereof removed;

FIG. 2 is a plan view, partially in section, and partially broken away showing side and bottom frame members, at a plurality of longitudinal stations along the length of the boat;

FIG. 3 is an elevational view, partially broken away, of the instant invention, showing the centerline girder thereof;

FIG. 4 is a transverse sectional view of the boat produced in accordance with the instant invention;

FIG. 5 is an enlarged transverse sectional view of a portion of the hull and framework showing the latter attached ot the hull;

FIG. 6 is a top plan view of the structure shown in FIG. 5;

FIG. 7 is an enlarged, transverse sectional view, partially broken away, of the centerline girder showing the connection between the girder and a pair of bottom frame members;

FIG. 8 is an elevational view partially in section taken on line VIII-VIII of FIG. 7;

FIG. 9 is a sectional view taken on line IX-IX of FIG. 7;

FIG. 10 is a transverse sectional view, partially broken away of a side frame member attached to the instant boat hull;

FIG. 11 is a sectional view, partially broken away, taken on line XI-XI of FIG. 10; and

FIG. 12 is an enlarged, sectional view of a portion of the structure shown in FIG. 10.

Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 in accordance with the invention, a plan view of a hard-chine boat 20, comprising a wooden hull 22 and a metal framework 24 fixedly mounted therein. 1

The wooden hull 22 comprises a pair of

side panels

26 and 28 joined to a pair of

bottom panels

30 and 32, all of said panels in turn being joined, at their respective rearmost edges to a transom member 34. The line of jointure between the side panels and the bottom panels forms the chine of the boat.

The

side panels

26 and 28 are connected to the respective

bottom panels

30 and 32 by one or more elongated strips of fiberglass cloth 36 extending the length of the line of jointure between said panels both inside and outside the hull, as can be seen in FIG. for example. Each fiberglass strip 36 is bonded to both the side panel and the abutting bottom panel by means of a plastic resin, such as either a polyester resin or an epoxy resin.

The respective

bottom panels

30 and 32 are connected together along the centerline of the hull in much the same manner that the side members are connected to the respective bottom members, that is, by resin bonding elongated strips of fiberglass cloth 38 to the respective bottom members in overlapping relation therewith on the inside and outside of the hull.

In FIG. 12 there is shown a modified structure for joining the

side panels

26 and 28 to the respective

bottom panels

30 and 32, wherein a plurality of laminated, resin bonded strips of fiberglass 36 are used, instead of the single layer 36 described above. In addition a quantity of fiberglass rovings 37 are inserted in a space between the adjoining side and

bottom panels

26 and 30, being resin bonded to one another and to said panels. The approach shown in FIG. 12 may of course be used in joining the

bottom panels

30 and 32 to one another. It has been found that the above described bond between wood and fiber-glass provides a substantially indestructible chine connection and also serves to eliminate the need for conventional cumbersome and diliicult to produce wooden chine strip generally used in connecting the side and bottom members of a hard-chine boat. The application of one or more resin bonded strips of fiberglass to the wooden side and bottom members to produce the instant chine structure is a considerably simpler and faster operation than that involving the production and connection of a conventional chine strip to a wooden hull. It has been found that the instant chine construction is substantially as strong as the aforementioned conventional chine structure yet it is far simpler, and less expensive to produce.

Following the connection of the

side panels

26 and 28 to the respective

bottom panels

30 and 32, and the connection of said bottom panels to one another, the entire hull, is covered with a resin bonded layer of fiberglass cloth 40 that extends from gunwale to gunwale, as shown in FIG. 4 for example.

Prior to the assembly of the framework 24 within the hull 22, the interior of the hull is provided with a plurality of longitudinal side-stringers 42 that extend the length of the boat and are connected to the

sides

26 and 28 by means of a suitable adhesive and/or screws (not shown). The respective bottom panels likewise are provided with a plurality of longitudinal stringers 44 extending the length of the hull and attached thereto by a suitable adhesive and/or screws. It is pointed out that the longitudinal stringers aflixed to the respective bottom panels of the boat may each be composed of a plurality of layers of wood in the manner shown in 'FIG. 5. In addition a plurality of transversely extending strips of wood 46 are affixed to the bottom, longitudinal stringers 44, at intervals of space corresponding to the space between successive bottom frame members hereinafter described in detail. Each of the wooden blocks or transverse strips 46 has a resilient rubber pad or other resilient means 48 of shock absorbing qualities covering its upper surface. The elasticity of the wooden blocks 46 with their pads 48, through which the impact load is transmitted to the frames, will not only be instrumental in distributing the load more evenly to the neighboring frames, but they will also absorb at least part of the initial shock of the impact. The side stringers 42 also have transverse wooden blocks 49 similar tothe blocks 46.

The aluminum framework 24 comprises a. rigid centerline girder 50, a plurality of longitudinally spaced transversely extending bottom frame members 52 attached to said girder, and a plurality of side frame members 54 affixed to the

respective side panels

26 and 28, and attached to the respective outer ends of said bottom frame members.

The center line girder 50 is connected to the bottom of the hull along the line where the respective bottom panels or skins 3t) and 32 meet and extends substantially the length of said hull, substantially as shown in FIG. 3.

As shown in FIGS. 3, 5 and 8, the center line girder 50 comprises an upper elongated T-shaped aluminum beam 56 extending the length of the hull and a coextensive lower plate-strip member 58. At a plurality of points along their lengths, the beam 56 and plate 58 are connected by means of a vertical brace 60. The braces 6% have a triangular bar 61 welded to each end through which the braces are bolted to the beam 56 and member 58. Each of the braces 60 also has a lug 63 welded thereto at its respective ends which extends transversely outwardly therefrom; each of said lugs 63 having a suitable bolt receiving hole extending therethrough. The center line girder 50 is further braced by means of diagonally extending bars 64 having their opposite ends affixed to the T-shaped beam 56 and the lowermost longitudinal plate member 58 by bolts 67. The diagonal bars 64 are also bolted to the vertical angle members 66 by bolts 66, as shown in PEG. 8.

The longitudinal plate 58 is attached to the hull bottom by means of a pair of elongated fiberglass cloth strips 68, each of which has a portion thereof resin bonded to the inner fiberglass strip 38 connecting together the two

bottom panels

30 and 32, while the remainder thereof is bonded to said plate 58. That portion of the respective longitudinal strips 68 connected to the center line girder is held thereto, in addition to aforementioned bonding means, by elongated, bolted strips of aluminum 70, as shown in FIGS. 5, 7 and 8. Although the bond between aluminum and fiberglass is not indestructible, the aforementioned linkage is as strong as if the bottom of the hull were attached to the girder 5t with mild steel angles fitted to both sides of the plate 58, as is conventional practice. It is pointed out that, since any force from an impact load tending to separate the two

bottom panels

30 and 32 bypasses the fiberglass angle connection, for reasons hereinafter set forth, and, since the greatest part of the impact load accelerates the hull through stringers and frames in a manner hereinafter described, there is only a small stress on the fastenings between the center line girder 5t and the hull bottom. In fact, the instant attachment technique of bottom to girder is stronger than any wooden linkage heretofore used, although the latter may have been made by the most skilled and conscientious craftsman.

As previously pointed out, the frame structure of the boat consists of a plurality of bottom frame members 52 and side frame members 54 located at longitudinally spaced intervals along the interior of the hull 22. Each of the bottom frame members 52 varies in length and in its dead-rise angle, depending upon the longitudinal station at which it is located; therefore suitable measurements can be made, and, by virtue of the nature of the invention, the various bottom frame members 52 may be assembled outside the hull and then connected to the center line girder within the hull, as hereinafter described. Each of the bottom frame members 52 comprises an upper, aluminum structural member 72 of any desired shape, but is preferably an angle member 72, said member being welded to a similar slanting angle member 74, said

angle members

72 and 74 being braced relative to one another by a plurality of bracing members '76 extending therebetween and having their respective ends welded to the respective angle members in the manner shown in FIG. 5. After each of the bottom frame assemblies 52 has been completed outside the boat, it can be heat-treated in any desired manner to restore the full strength of the aluminum alloy used. As a matter of fact, all of the aluminum sub-assemblies may be heattreated for similar purposes.

Each of the side frame members 54 is formed of an elongated aluminum section, preferably an angle member that is cut to a suitable predetermined length at some location outside the boat, and then heat-treated in the same manner as the bottom frame assemblies 52.

Referring to FIGS. 5, 7 and 9, it is pointed out that each of the bottom frame members 52 is connected to the centerline girder 50 and to the side frame members 54, respectively, by means of a plurality of aligning or universal joints. Identical universal joints are used to connect the various frame members 52 to the centerline girder 50 and the respective side frame members throughout the length of the boat, and, therefore, can be massproduced at some point and time prior to assembly of the frame members into the boat. In a high speed planing boat the angle between the hull bottom and the horizontal, that is the dead-rise angle, usually varies throughout the length of the boat. Metal frame construction in the past has therefore required a slightly different joint configuration for each frame member. The purpose of the instant universal joint is to make the joint between the frame and centerline girder identical at each frame location and, accordingly, to reduce the design and construction costs. The instant universal joint adapts itself to the particular angle of the hull bottom at each frame location. Furthermore, the universal joint connection adapts itself to the inevitable small errors that arise in the manufacture of the parts of the boat. It, for example, the lug members 63 on the centerline girder are situated at a slight upward or downward angle instead of being horizontal, the universal joint connection adapts itself to this angle and makes it possible to obtain the desired tight-fitting connection between frame and the centerline girder. Each of the universal joints connecting a bottom frame member to the centerline girder includes a pair of spaced lugs 80 on the inboard end of the upper and

lower angle members

72 and 74, respectively, said lugs being laterally spaced from one another in the manner shown in FIG. 9, and each has a bolt hole extending through it, the axis of each of said holes extending at right angles to the axis of the hole in the respective lug 63 on the vertical brackets 60 attached to the center line girder 50. It is pointed out that the lugs 80 on the bottom frame members 52 may be formed in any desired manner. Each universal joint further comprises a U-shaped yoke member 82 having a bolt receiving hole 84 extending through the bight portion thereof, said bight portion being located between the lugs 80 on each of the bottom frame members 52 and having the hole therein in alignment with the holes in the respective lug elements 80. Suitably sized bolts 86 extend through the holes in the yoke 82 and the yoke straddling lugs and are held in place by a nut 87 affixed to the threaded end thereof, whereby said yoke member is adapted to pivot relative to each of the

angle members

72 and 74. Each of the spaced legs of the yoke member 82 is provided with a bolt receiving hole of the same size as the hole in each of the lugs 63 on the center-line girder, said spaced legs being arranged in lug straddling relation with the respective lugs on the center-line girder 50. A bolt 90 is inserted through the holes in the yoke arms and each lug 63 respectively and bolted down with a suitable nut 92 on the threaded end thereof. Thus it can be seen that each of the elements of the bottom frame member 52 is adapted to pivot relative to the center-line girder in a universal manner, whereby it is possible to make slight adjustments for minor variations in size and shape which may result during manufacture of the various elements of the frame work.

It is pointed out that the upper lug members 63 on the center-line girder 50 are thinner than the lower lugs 63 thereby providing a slight gap between said upper lugs and the respective legs 88 of the yoke member 82 in order to compensate for slight discrepancies in manufacture. The slack space between each upper lug 63 and the respective legs of each of the yoke members is taken up by inserting suitably sized U-shaped shims 94 between the respective surfaces of the lug member and the inner surfaces of the respective legs of the yoke element.

During fabrication, each of the side frame members 54 is provided at its lower end with an inwardly extending lug 96 having a bolt hole extending therethrough, said lug member being the same in size and shape as the lowermost lug 63 on the centerline girder. Each lug 96 extends inward of the side frame member substantially at right angles to the surface to which it is welded before the frame member is heat-treated as previously described. The outermost end of the lower angle element 74 of the bottom frame member 52 is provided with a pair of spaced lugs 98 welded thereto in the same manner as the inboard lugs 80 are welded to its opposite end, said lugs being spaced apart the same distance as said first-mentioned pair of lugs 80 and having the same sized bolt holes provided in each thereof. Another yoke member 82 of the same size and shape as the yoke members used on the inboard universal connection between the bottom frame member and the centerline girder is provided for connecting the outboard end of each bottom frame member with the respective side frame members and is connected to each of said frame members by means of

suitable bolts

100 and 102 extending at right angles to one another in substantially the same manner as the connection between the inboard ends of each bottom frame member and the centerline girder, all as shown in FIGS. 5 and 6.

Thus it is emphasized that, by virtue of the universal joint connection described above, the applicant has provided a simple and rigid connection means between the respective bottom frame members 52 and the centerline girder 50 and also with each of the side frame members 54,- each of said connections being substantially identical and being capable of connecting together the respective bottom frame members with the centerline girder regardless of the particular dead-rise angle at the point where the respective bottom frame members are located, and also regardless of the angular relationship between the respective side frame members and the associated bottom frame members; the latter feature being shown in FIG. 2.

Each of the bottom frame members 52 is firmly connected to the respective bottom panels of the hull by means of a plurality of suitably sized bolts 104, each of which has one end anchored in the respective bottom panels and extends through suitably sized holes in the longitudinal stringers 44, the strip 46, the resilient pad 48 and a portion of the lower angle member 74, each of said bolts being anchored with a nut 106 threaded onto the free end of said bolt that extends through the angle member 74.

Each of the side frame members 54 is, in turn, anchored to the respective side panels by means of suitable bolts 108, each of which has one end anchored in the side panel, and extends through the respective stringers 42 and a portion of said side frame member, all in much the same manner that each of the bottom frame members 52 is anchored to the bottom of the hull.

It is emphasized that the aforementioned connections between the various framework elements, and between the framework and the hull serves to provide an exceptionally rigid connection between the respective bottom frame members 52 and the centerline girder 50. Thus any impact load applied to the bottom of the hull is transmitted through the vertical plate member 58 on the centerline girder, to the centerline girder, thence through the universal connections to the respective bottom frame members 52 immediately adjacent to the area of impact application.

Furthermore, since the overall framework is extremely rigid, the force of an impact load is transmitted along the centerline girder 50 to adjacent bottom frame members, and thence through said bot-tom frame members to the side frame members 54 to the side of the hull, thereby substantially bypassing the chine of said hull, thus eliminating excessive strain on said chine. This is accomplished by letting the chine float on the side and bottom panels which are both free to flex at the chine, while the impact load is transmitted directly from the bottom panel or skin to the side panel or skin. For example, in FIG. 10, an impact load on the bottom panel 30 passes through stringers 44 into the metal framework and back to the side panels through side stringers 42, thereby bypassing the chine. Flexibility rather than rigidity is provided in the chine.

The chine is not called upon to transmit the full forces on the hull but is made flexible but waterproof so as to accommodate itself to the applied forces.

The instant invention also provides a rigid metal framework for use within a wooden hull,..which framework is so constructed and arranged as to distribute over substantially the entire hull any impact load which may be applied to the bottom of the hull, thereby materially reducing acceleration loads on the hull brought about by impact with waves. In addition to the framework being extremely rigid, it is also quite simple to manufacture and, by its very nature, need not be assembled piece by piece Within the boat, but rather can be manufactured in the form of sub-assemblies at some remote point.

The instant invention also provides a simple connection between a centerline girder of a boat and the bottom frame elements that extend laterally therefrom by utilizing a universal connection, all the elements of which are substantially identical throughout the boat construction, thereby materially reducing the cost of construction and the time required therefor.

Obviously many modifications and variations of the present invention are possible in light of the above tea-chings. It is therefor to be understood within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A boat construction comprising a hard-chine hull, a metal framework within said hull and rigidly fastened thereto at selected points, said framework comprising a center-line girder attached to the bottom of the hull along the center-line thereof, a plurality of transverse bottom frame members attached to said center-line girder and extending laterally therefrom toward the sides of said hull, a plurality of side frame members equal in number to said bottom frame members, each of said side frame members being fastened to a bottom frame member at the outboard end thereof, said framework being free of attachment to said hull along the respective chines thereof;

2. A boat construction as setforth in claim 1, wherein each of said bottom frame members is located in a vertical plane and is substantially V-shaped having the apexthereof connected to a said side frame member, the spaced ends of said V-shaped member being connected to said center-line girder.

3. A boat construction as set forth in claim 2, wherein each of said bottom frame members is connected to the center-line girder and the side frame member with universal joints.

4. A boat construction as set forth in claim 3, wherein each of said universal joints comprises a U-shaped yoke member having the bight portion thereof pivotly connected to one of said interconnected frame members and the legs thereof pivotly connected to the other of said interconnected frame members, the axis of the respective pivots extending at right angles to one another.

5. A hard chine boat construction comprising a hull having a pair of side panels, a pair of bottom panels, said side panels each being connected to respective bottom panels by a layer of fiber glass resin bonded to both said side panels and an immediately adjacent bottom panel, said bottom panels being connected to one another along the centerline of said hull by a layer of fiber glass resin bonded to both bottom panels, a metal framework within said hull that includes a centerline girder, a fiber glass member resin bonded respectively to said centerline girder and the layer of fiber glass connecting together the bottom panels, whereby said centerline girder is con nected to said hull; said framework further including a plurality of bottom frame members each of which is connected to said centerline girder and extends transversely thereto toward the respective sides of the hull, a tightenable universal joint connecting each of said bottom frame members to said centerline girder.

6. A hard-chine boat construction as set forth in claim 5, wherein said framework includes a plurality of substantially vertical side frame members connected to the respective side panels of said hull, and universal joint means connecting said side frame members to said bottom frame members, said framework being free of connection to said hull along the respective chines thereof.

7. A boat construction as set forth in claim 6, wherein each of said universal joints comp-rises a U-shaped yoke member having the bight portion thereof pivotly connected to frame members and the legs thereof pivotly connected to the other of said interconnected frame members, the axis of the respective pivots extending at right angles to one another.

8. A boat of a type described comprising a hull having a bottom skin, a side skin and a longitudinal joint joining said bottom and side skins along a chine line, a plurality of spaced longitudinal wooden bottom stringers along said bottom skin, a plurality of spaced transverse wooden blocks across said stringers, a plurality of transverse metal bottom frames along said wooden blocks, means securing said bottom skin, bottom stringers, transverse blocks and bottom frames together and a resilient pad sandwiched between each of said transverse blocks and the bottom frame resting on said block being in contact with both, whereby impact forces applied to the bottom of said hull are transmitted by said bottom stringers longitudinally of said hull to a plurality of adjacent transverse metal bottom frames; a plurality of spaced longitudinal wooden side stringers along said side skin, a plurality of spaced transverse metal side frames, means securing said side skin, side stringers, and side frames together, said bottom frames and side frames being arranged in substantially aligned transverse pairs, and means securing an end of a side frame to the adjacent end of a bottom frame of each said pair.

9. A boat as defined in claim 8 but further characterized 1 l by the last said means comprising a lockable universal joint.

10. A boat as defined in claim 8 but further characterized by a centerline girder, and a lockable universal joint securing the neighboring ends of said bottom frames to said girder, and by the last said means comprising a lockable universal joint.

11. A boat of a type described comprising a hull having a bottom skin and a side skin, a transverse metal frame along said bottom skin, a transverse frame member along said side skin, and a lockable universal joint interconnecting said frame and frame member.

12. A boat construction comprising a hard chine hull, a metal framework within said hull and rigidly fastened thereto at selected points, said framework comprising a center line girder attached to the bottom of the hull along the center line thereof, a plurality of transverse bottom frame members a tightenable universal joint connecting each of said bottom frame members to said centerline girder, and said transverse bottom frame members extending laterally from the centerline girder toward the sides of said hull, a plurality of side frame members, each of said side frame members being fastened to a bottom frame member at the outboard end thereof, said framework being free of attachment to said hull along the respective chines thereof.

13. A boat construction as set forth in claim 12, wherein each of said universal joints comprises a U-shaped yoke member having a bight portion thereof pivotally connected to one of said interconnected frame members and the legs thereof pivotally connected to the other of said interconnected frame members, the axis of the respective pivots extending at right angles to another.

14. A boat construction as set forth in claim 12, wherein each of said bottom frame members is connected to a side frame member with a universal joint.

15. A boat construction as set forth in claim 14, wherein each of said last named universal joints comprises a U- shaped yoke member having a bight portion thereof pivotally connected to one of said interconnected frame members and the legs thereof pivotally connected to the other of said interconnected frame members, the axis of the respective pivots extending at right angles to one another.

16. A boat construction comprising a hull having interconnected bottom and sides, a plurality of stringers extending lengthwise along said hull, a metal framework within said hull resting on said stringers and fastened therethrough to said hull, said framework comprising bottom and side frame sections and means joining said sections in a relatively adjustable manner, said means comprising a plurality of lockable aligning joints interconnecting said bottom and side frame sections, whereby to lock said sections together during assembly, although they may be slightly out of line.

17. A boat comprising a bottom and sides, a plurality of spaced stringers extending lengthwise of the bottom, a framework resting on said stringers, said framework comprising a center line girder along said bottom, and a plurality of pairs of frame members spaced lengthwise, each of said pairs of frame members comprising a frame member disposed transversely on each side of said center line girder, and lockable aligning joints fixedly connecting each of said frame members to said center line girder, each of said joints having parts that are relatively movable when the joint is unlocked to provide for alignment of said frame members to said center line girder when the joint is locked.

18. A boat construction comprising a hard chine hull having a bottom and sides interconnected with said bottom at its lateral edges thereby forming a plurality of chines, a plurality of stringers extending in a direction substantially parallel to said chines, a metal framework within said hull resting on said stringers and fastened therethrough to said hull, said framework comprising bottom and side frame sections and means joining said sections in a relatively adjustable manner, said means comprising a plurality of lockable aligning joints interconnecting said bottom and side frame sections in a region substantially juxtaposed to said chines, said region of interconnection being spaced from and free of attachment to said hull along the chines thereof, whereby said bottom and side panels are capable of movement relative to each other in said region of interconnection.

References Cited in the file of this patent UNITED STATES PATENTS 1,067,659 Kankkonen July 15, 1913 1,114,996 Lawson Oct. 27, 1914 1,333,248 Di Carlo Mar. 9, 1920 1,636,076 Ruthenburg July 19, 1927 1,679,630 Roys Aug. 7, 1928 2,412,455 Hall Dec. 10, 1946 2,547,146 Anthony Apr. 3, 1951 2,612,129 Burch Sept. 30, 1952 2,746,891 Doane May 22, 1956 FOREIGN PATENTS 328,458 Great Britain May 1, 1930 541,178 Great Britain Nov. 17, 1941