US 3093847 A
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June 18, 1963 w. v. sTREcKER REINFORCED FIBER GLASS STRUCTURE Filed Sept. '7, 1961 United States Patent O 3,093,847 REINFRCED BEBER GLASS STRUCTURE William V. Streelrer, lil 7irzirkspur Drive, W est Islip, FLY. Filed Sept. 7, 196i, Ser. No. 136,562 l Claim. (Cl. 9 6) This invention relates to reinforced structure utilizing ber glass, and more particularly to such means and methods for constructing structural surfaces which have compound curves.
More particularly the invention relates to means and methods for constructing contoured surfaces, for instance, for making boats.
The invention generally utilizes long ilexible hollow members for instance, made of extruded plastic. The members have a projection on one side for interlocking into a groove the other side the adjoining member. The grooves formed by the interlocking joints 4are lilled with liber glass reinforced cement. Fiber glass cloth may be laid over and cemented to the outside of the structure with plastic cement when completed.
The present invention has several advantages, for instance, the hollow members have a density of less than one, so that iiotation is built in which is a very desirable feature for boats. Also the members themselves comprise box girders having a high strength in proportion to their Weight. The members have suihcient flexibility so that they may form surfaces having compound curves when laid up on frames or forms of the desired configuration.
Another advantage of the present invention is that it permits the use of the liber glass construction without the necessity for molds.
Accordingly a principal object of the invention is to provide new and improved structure means.
Another object of the invention is to provide new and improved structural members having high strength and density of less than one.
Another object of the invention is to provide new and improved means for forming structural surfaces having compound curves.
Another object of the invention is to provide new .and improved means and methods for making liber glass structures.
Another object of the invention is to provide new and improved means and methods for constructing boats or other structures having compound curves.
Another object of the invention is to provide new and improved structural members comprising a long hollow Flexible member with a cross section having a socket portion at one side and a curved portion .at the other side adapted to snap into the socket portion of an identical adjoining member and hinge therein.
Another object of the invention is to provide a new and improved process for building a boat of fiber glass without molds.
Another object of the invention is to provide new and improved process for building a boat including the steps of forming planking consisting of lengths of hollow plastic having interlocking joints, applying fiber glass roving and plastic cement along the grooves formed by said inten locking joints both inside and outside, and applying at least one layer of fiber glass cloth over said planks.
These and other objects of the invention will be apparent in the following specification and drawings of which:
FIG. 1 is a perspective view of a boat embodying the invention and partially cut away to show details.
FIG. 2 is an enlarged sectional View of the interlocking hollow members of ythe invention and,
FlG. 3 is a further enlarged view of the interlocking hollow members.
Referring to the ligures the basic construction comprises laying up a plurality of interlocking hollow members lil, il, l2, so forth. The hollow members may be formed of a conventional plastic and extruded in the cross sectional form shown, having a socket i3 curvature along one edge and a curved projection lid along lthe other edge. rihe curved projection is adapted to snap into the socket portion which is suiciently iiexible to expand and receive the projection portion so that the socket portion is held with a positive mechanical force. The hollow members are sealed at each end, for instance with plugs or cemented joints.
As illustrated in FlG. 2, this construction permits the construction of a curved surface of any practical desired degree of curvature. The joints formed oy the interlocking connections are filled with fiber glass roving lo and cement i7 FIG. 3. iter the cement is hardened the planks may be sanded down to achieve a smooth surface.
Thereafter, one or more layers of fiber glass cloth 2d, Zi, and 22, 23 may be laid over the basic structure.
In order to lay up the hollow plank members in the proper configuration they must be laid over mold frames for instance, the frames 2d, 25', illustrated in PEG. l. The trames may remain as a permanent part of the structure or may be removed as desired. Permanent bulkheads would also act as mold frames. v
in the embodiment illustrated in PEG. l, the keel l `stem 2 and transom 3 may be constructed in the conventional manner used in making wooden boats. rthen the planks liti, lll, l2 of the present invention are laid up on the frames either from the keel or from the deck side. The ends of the planking are cemented to the transom and the keel which may be notched or otherwise shaped to receive them. All joints are cemented and reinforced with liber glass cloth.
Referring to the illustration in FIG. l, the frames 2d, 25 remain a permanent part of the structure if desired or may be removed since the strength of the planking members is sufficient without the frames.
This method of construction is an improvement of the conventional fiber glass construction which requires the use of elaborate molds. The use of the present system is lespecially `advantageous when custom building where the cost Vof a mold would be prohibitive, or where many boats had to be built at the same time.
The detailed steps in the process are as follows:
(l) Erect keel il, stern 2, and transom 3, as in conventional wood boat construction.
a. Keel and stem `are preferably of laminated wood to lighter scantlings than is customary, the laminations either sawn with joints vertical or steam bent with seams horizontal or a combination of both methods as might yseem to be required by the design being executed. These can also be preformed plastic.
b. Transom 3 can be of laminated wood or can be fabricated of extruded interlocking liberglass strips in two layers, the inner layer vertical, strips normal to the curvature of the transom as is generally the case and then covered with iiberglass both sides. The outer or rearmost surface is then covered, at with the liberglass interlocking strips and bonded to the first this in turn being covered with one or more layers of liberglass. The joints between the strips will be treated in the same way as the joints in the planking in FlG. 3,
(2) Bulkheads or temporary frames 24, 25 are next erected and made fast to the wood keel as required, All items now being squared and properly crossbraced, the hull is ready for the planking.
a. Bulkheads can be built up in the same manner as was the transom and covered with .thin plywood over the iiberglass for esthetic eect being trimmed. out with solid Wood molding etc. in keeping with the wood used in the panel selected. An area along the edges of the bulkhead where it will ljoin the planking and the deck must be kept free to allow the bonding of all these members together.
(3) Planking which consists of strips litt, l1, l2 etc. of ,extruded fiberglass reinforced plastic shaped so as to be interlocking and capable .of hinging one on another, are next `applied to the hull. Planking will start either at the keel and be applied toward the sheer or from the sheer to the keel depending upon the design being executed as the shape will tell best which method to choose. If the design .requires a shelf, clamp and stringers these ought to be applied before the planking especially if planking is to proceed `from the sheerline down. Clamp and shelf can be fabricated 'from the same strips as the planking and assembled the same way. |The p-lanking is bonded to stem, permanent bulkhea'ds and transom with suitable adhesive, and temporarily clamped .to the mold iframes to maintain the hull shape. Planking is applied by laying the bead of one plank onto the groove of the preceeding plank and forcing the bead into the Igroove with light blows of a soft hammer. There is enough spring in the material to allow .this to work without overstressing the plank or doing any damage to it. After a number of planks are in place the grooves between the planks yare filled with a suitable adhesive with ber glass moving embedded and screeded flush with the planking. This bonding will hold the shape of the hull through the operations that will follow. The `grooves inside the hull are filled the same way at the same time Wherever they are free to be gotten at.
When plankup is completed the entire hull is sanded to fair curvatures with coarse paper, care being taken not to remove too much material. The rough sanded surface must be then cleaned of all foreign matter and grease yand is then ready to receive one or more layers 20, Z1 of fiberglass-cloth reinforced plastic. Areas that will be under great stress or are apt to be abraded can be given as many layers `of cloth and resin as required and the edges of these areas feathered into the adjoining areas in such a way as to give a fair hull. Final finish can then be ygiven to the hull. All temporary frames can now be removed and the inside of the hull finished as was the outside, after being sure that :all seams between planks have been properly filled.
(4) Deck and deck beams can now be made and applied. The deck beams may not be required in some hulls and can be eliminated. I a. Beams can be fabricated to sizes and strengths required by t-he design out of the same strips as the planking, using the same methods. By bending a number of strips over a rough form, bonding them together and covering them with one or more layers of fiberglass cloth and resin suitable beams can be built. The beams can be made fast inside the hull in `a number of ways and decking is now possible.
b. Decking is done with the same strips as was the planking and in the same fashion with the choice of either laying the strips fore and aft parallel with the keel or following the curvature of the sheer strake. An alternate method is to erect suitable forms longitudinally and lay the deck athwartships covering it with a number of layers of fiberglass cloth Iand resin, after which the forms will be removed yand the interior or underside of the deck treated in the same -manner as the top side of the deck.
#(5) Interior joiner work and deck house and any other deck structure can now be built onto the hull, .machinery installed and the rest `of the work that goes into the finishing of a boat completed. Tanks for fuel and for water can be built into the hull at this time using .the same fiberglass cloth and resin covered strip method as was used in the hull using sensible design of course. Internal wiring can be built into the hull at this time by drilling through the inside layers of the planking at points of wire ingress and egress and sealing same into planks where they pass through it. A similar arrangement is possible with some of the piping in the smaller sizes, if provision is made for it at the time the planks are laid. In some cases the hollow strip itself could be used to carry water throughout the hull although this practice certainly is not recommended for fuel.
Summary It can be seen by anyone familiar with the manufacture of wooden or conventionally molded fiber-glass reinforced plastic boats that this system of construction offers a number lof advantages. First among these is the fact that 'a custom built fiberglass boat is possible without incurring the expense fof a plug and a female mold While still allowing close control of shape and form which is especially importan-t in a sailing hull. Then too it is possible to build a much stronger hull `of the same weight than a conventionally molded hull by the `simple layup process. The strip construction gives a very stnong longitudinally framed hull and the roving in the seams adds to this strength. The fiberglass cloth covering serves to nish off the hull and performs the same function as conventional frames. Greaterl distance between transverse members is possible because the keel is much stiffer than the same Weight in solid plastic glass laminate, and less tendency to pant accrues. Last but perhaps not least is the fact that this type of hull structure can have a density of less than one and will therefore iioat dispensing with the bulk of foam flotation material generally required with other types of plastic hulls.
lt should be mentioned here that this system is by n0 means limited to the use of fiberglass reinforced plastic extrusions. Strips can be made in the form fof aluminum extrusions. ln the case of 'aluminum extrusion-s the seams between the planks would be filled by welding after planks are in place. The exterior can be ground to fair curvature and given a covering layer of fiberglass for protection from the elements and for appearance. The actual shape of the extrusion would be dictated by the size required for a given class of structure but would retain the important interlocking feature-s already outlined.
The fiberglass roving used in filling the seams between the planks will add quite considerably to the strength of the structure much as reinforcing rods ldo in concrete work. The advantages of heat and sound insulation are real benefits in that the slower transfer of heat will prevent much condensation of moisture inside the hull and add materially to the living comfort as will the sound fdeadening qualities of the material.
Splicing blocks, not shown, may be used in the actual work to make possible the use of random lengths of the material. These too will be extrusions that will lit the rinside shape of the extrusion and will be cemented into place with la suitable adhesive. Random lengths of aluminum may be welded. Little waste of material results with the use of this system.
'the life of a structure made in this fashion will be considerably longer than that of a wooden `one of a sirnilar nature in that it will not be subject :to attack by rot or insects and because it absorbs practically no moisture its weight will remain constant. A Wooden hull can absorb as much as ten time.
Although the present invention is illustrated in connection with the construction of boats, it is not so limited, but may be used for many different types of structural members, for instance, vehicle bodies, truck bodies, and in any application where strength `and light weight are required. lt is especially advantageous in those applications where compound curvature surfaces are required.
Many modifications may be made by those desiring to practice the invention without departing from the scope thereof, which is defined by 'the following cla-im.
percent of its own weight in a short I claim:
A ber glass hull comprising a conventionally constructed keel, stem, and transom, a plurality `of frame members connected to said keel, `said frame members lbeing spaced along said keel, a plurality of continuous elongated exible hollow plastic extruded planks connected to said frames, said hollow planks having interlocking connections along their entire length, said hollow planking members being sealed at their ends to provide flotation for said hull, said planks having a :cross section having a socket portion at one side and a projecting portion at the other side, said projecting pontion being adapted to snap into said socket portion of an adjoining member :and to be held therein with a positive mechanical force developed by physical interference, said sealed hollow planks having a density of less than one, and means to seal and reinforce 6 the surface grooves formed by said connections icompnising a filling `of fiber glass roving `.and plastic cement, said plastic plank construction having negligible water absorption.
References Cited in the le of this patent UNITED STATES PATENTS 2,354,485 Slaughter Iuly 25, 1944 2,700,357 Winter Jan. 25, 1955 2,743,465 Vogel May 1, 1956 2,833,682 Laszlo May 6, 1958 2,941,216 Carlson June 21, 1960 FOREIGN PATENTS 1,016,004 Germany Sept. 10, 1957