| US3711581A | 1973-01-16 | |||
| US3611461A | 1971-10-12 | |||
| US4365580A | 1982-12-28 | |||
| US3435470A | 1969-04-01 | |||
| US3848284A | 1974-11-19 | |||
| US4021874A | 1977-05-10 | |||
| US4161796A | 1979-07-24 | |||
| US4411214A | 1983-10-25 |
| 1. | A boat compris ing : a nonstructural thermoplastic hull which is vacuumformed from a first single sheet; c a nonstructural thermoplastic deck which is vacuumformed from a second single sheet; an elongated frame; said frame being bonded to the bottom side of said deck, and said deck and said hull being bonded at the 10 gunwale to form a watertight cavity therebetween containing said frame; low density plastic foamed in place to fill said cavity, bonding to said hull and deck and locking said frame in place; 15 said foamed plastic forming the structure of the boat with said frame so that loads are carried through said frame and supported by said foamed plastic. |
| 2. | A boat according to Claim 1, wherein said deck is formed with a central recessed portion to form an 20 integral cockpit. |
| 3. | A boat assembly according to Claim 2, further comprising a rolling seat carriage, wherein a track for said carriage is formed in said cockpit. |
| 4. | A boat according to Claim 3, wherein said 25 track is formed on top of the bonded area between the frame and deck, so that the loads from said seat are applied to said frame. |
| 5. | A boat comprising: a nonstructural thermoplastic hull formed from a first single sheet of coextruded acrylic resin and ABS; a nonstructural thermoplastic deck formed from a second single sheet of coextruded acrylic resin and ABS; an elongated frame formed from two members which are angleshaped in crosssection; an integral cockpit formed in a central recessed area of said deck; said members being mounted to said deck along the sides of said cockpit; said hull and said deck being bonded along the gunwale to form a watertight cavity therebetween; low density plastic foamed in place to fill said cavity, bonding to said hull and said deck and locking said frame in place; a rolling seat carriage; a track for receiving said carriage formed on that part of said deck which is bonded to said frame; an outrigger extending to both sides of said boat; oarlocks mounted near both sides of said outrigger; support means for mounting said outrigger to said frame; a footboard mounted on said support means; wherein said frame gives structure, said foamed plastic gives panel stiffness and said hull and deck give shape to said boat; and wherein the forces due to the action of rowing and the weight of the oarsman are carried through said frame and supported through said foamed plastic. |
| 6. | A method of making a marine device comprising the steps of: vacuumforming a thermoplastic hull from a first single sheet; vacuumforming a thermoplastic deck from a second single sheet; bonding an elongated frame to the bottom of said deck; bonding said deck and hull to form a watertight cavity; foaming low density plastic in said cavity to form the structure of the marine device with said frame. |
| 7. | A method of making a marine device according to Claim 6, further comprising the step of forming an integral cockpit in a recessed area of said deck. |
| 8. | A method of making a marine device according to Claim 6, wherein said deck and hull are bonded along the gunwale. |
| 9. | A method of making a marine device comprising the steps of: forming a thermoplastic hull; forming a thermoplastic deck; placing an elongated frame between said hull and said deck; bonding said deck and said hull to form a water¬ tight cavity containing said frame; foaming low density plastic in said cavity to form the structure of the marine device with said frame. |
| 10. | A boat comprising: a thermoplastic hull; a thermoplastic deck; an elongated frame; said frame being bonded to the bottom side of said deck; said deck and said hull being joined to form a nonstructural envelope with defines the shape of said boat and provides impact resistance; low density plastic foamed in place to fill said envelope, bonding to said envelope and locking said frame in place; said foamed plastic forming the structure of the boat with said frame so that loads are carried through said frame and supported by said foamed plastic. |
Rowing Shell
Technical Field:
This invention relates generally to a boat formed from plastic sheets and more specifically to a rowing shell made from plastic sheets and foam using a structural frame to distribute the various loads.
Background Art:
The wide availability of plastic materials in modern times has provided boat manufacturers the possibility of utilizing new construction techniques in the manufacture of boats. Plastic materials are inexpensive, ease to shape, resistant to water damage, bouyant and readily available. Accordingly, many new boat constructions have occurred which utilize these properties.
One such boat constuction is shown in U.S. Patent 3,611,461. This rowing shell is fabricated from sheet and foam plastics and uses a vacuum-formed hull. However, this boat does not have a frame for effectively supporting the forces and loads on the boat.
Other devices, such as shown in U.S. Patent 4,227,272; 4,407,216; and 4,229,850 show boats with structurally supportive frameworks. However, these devices are relatively complex and expensive to make.
Disclosure of the Invention
Accordingly, one object of this invention is to provide a novel boat fabricated from plastic sheets.
Another object of this invention is to provide a light weight rigid and low cost boat.
A further object of this invention is to provide a novel boat formed from plastic sheets with foamed plastic filling the space between the sheets.
A still further object of the invention is to provide a novel boat having a composite frame attached to the body of the boat.
Another object of the invention is to provide a novel boat having a framework to receive the applied forces which utilizes the tensile and compressive strength of the rigid plastic foam to distribute the forces created by rowing.
These and other objects of the invention are achieved by providing a boat formed from, two vacuum- formed plastic sheets joined along their edges and filled with a foamed plastic material. A structural frame attached to the sheets supports the forces on the boat and distributes them through the boat body.
Brief Description of the Drawings
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following Detailed Description when
considered in connection with the accompanying drawings, wherein:
Figure 1 is a top plan view of the boat of the present invention.
Figure 2 is a right side elevation of the boat of the present invention.
Figure 3 is a top view of the boat shown in Figure 1 with the interior structural frame being shown.
Figure 4 is a vertical cross section of the boat shown in Figure 1.
Figure 5 is another vertical cross section of the boat shown in Figure 1.
Figure 6 is a perspective view of the construction of the outrigger and footboard.
Figure 7-10 are cross sectional views of different embodiments of the framework of the present invention.
Figures 11-13 are top side and cross sectional views of the boat of the present invention showing the placement of loads.
Best Mode For Carrying Out the Invention
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to Figure 1 thereof, where a boat 10 is
shown as including a deck 12. The center portion of the deck is recessed to form an integral cockpit 14 in which the oarsman may sit. The cockpit includes a rolling. seat carriage 16 which rides on tracks 18 placed on either side of the cockpit. A footboard 20 is placed for receiving the feet of the oarsman. A V-splash 22 is placed at the front of the cockpit. An outrigger structure 24 is mounted just behind the footboard. The ends of the outrigger extend outwardly and forwardly and include oarlocks 26 at each end of the outrigger.
Figure 2 shows a side view of the same boat. As can be seen in this Figure, deck 12 rests on top of hull 30 to form the body of the boat.
in order to give overall rigidity and strength to the boat, a structural frame 32 is placed inside the boat and parallel to the longitudinal axis thereof as shown in Figures 3 and 4. This frame may be angle- shaped in cross section, as shown in Figure 5. The frame pieces- are formed from fiber reinforced plastics based on a bi-axial orientation fiberglass profile with unidirectional graphite fibers used for the directions of extreme load.
In forming the body of the boat, the hull 30 and deck 12 are each formed from a separate single sheet of thermoplastic polymer which is heated and vacuum formed over a mold. The hull is formed over a male mold while the deck is formed on a female mold. The sheet material used is a co-extruded sheet having an outer layer of acrylic resin and a substrate of ABS(acrylonitrile-butadiene-styrene) .
The structural frame 32 is chemically bonded to the deck 12 along the full length of the sides of the cockpit. The deck may then be joined to the hull by chemical bonding along the gunwale to create a single water tight body. The joint may be trimmed to a 1/4 inch wide flange, and covered with a nylon or other suitable impact edge. The cavity formed between the hull and deck is then filled with a pour-in-place urethane plastic foam having a nominal density of about 1.5 lb/ft3. The foam fills the entire cavity, bonds chemically to the surface of the deck and hull and gives a general panel stiffness to the boat body. Since the foam fills the entire cavity, it also locks the frame into place. Since this foam is also bouyant, it makes the boat unsinkable.
A rolling seat carriage 16 is provided in the cockpit to allow the oarsman to be seated and to move fore and aft as he rows as shown in Figures 4 and 5. The wheels of the carriage rest on a track 18 which is formed on the upper surface of the deck. This part of the deck is in contact with the frame structure so as to support the weight of the carriage and oarsman.
The V-splash 22 is formed by a separate operation and chemically bonded into place after the hull and deck are already assembled.
Outrigger stands 34 are placed on the upper surface of the deck at the end of the seat tracks as shown in Figure 6. As mentioned above, the tracks overlay the frame at this point and thus are fully supported by the frame. The stands are bolted through the deck and frame to a backup plate (not shown). The stand provides support for both the outrigger 24 and
the footboard 20. The footboard is made of thermoplastic material and includes a brace 38 wh extends transversely to the axis of the boat. The footboard may be adjusted along the axis of the boat so that the brace fits into one of several notches available on the notch adjustment tract 40. The top section of the footboard includes an adjustment slot 42 which receives adjustment bolt and nut 44. The nut and bolt may be tightened after the footboard is in the desired position.
The outrigger 24 is also supported by the supports 34. Matching holes 46 are provided in the outrigger and the supports for receiving bolts or other attachment devices for holding the outrigger to the stand. The outrigger is composed of a composite of triaxially oriented glass and graphite fibers bonded to a rigid 5 lb density foam with epoxy resin. A higher density core may be used where the outrigger is attached to the supports. Oarlocks 26 are provided at the ends of the outrigger The oarlocks are directly bolted to the outrigger.
Figure 7 shows a cross sectional view of the frame structure 32 embedded in the foam 36. While this is the generally preferred shape, the angle can be varied away from 90° if desired. Also, a different structural shape may be used, such as the circle shown as 32 ! in Figure 8. The frame can also be a channel-shaped structure standing on its side, such as shown by 32" in Figure 9. The frame could also be a T-shaped structure such as shown by 32'" in Figure 10.
In the normal operation of rowing, various forces are applied to the different parts of the boat body.
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By utilizing the invention as described above, all the forces are supported by the structural frame which in turn distributes the forces through the foam and hull sheet. Figures 11, 12 and 13 show top, side, and cross sectional views of the subject boat with various arrows indicating the direction of application of various forces on the parts of the boat. Arrow 1 indicates the load applied when the oars are pulled to drive the boat forward. Arrow 2 indicates the forces applied during the recovery stage, when the oars are returned to their starting position. Arrow 3 indicates the force applied to the footboard by the legs of the oarsman as the oars drive the boat forward. Arrows 4 and 5 indicate the loads applied to the ends of the outriggers during the catch and finish stages of the rowing cycle respectively. During these stages, the oars are pushed down into the water and lifted back out of the water respectively. Arrow 6 indicates the load carried by the rolling seat carriage, including part of the weight of the oarsman. Arrow 7 indicates the remaining weight of the oarsman carried through the feet. Arrow 8 indicates the front and back forces applied through the carriage.
The various loads indicated by arrows 1-8 are applied to the boat through the structural frame.
Forces 1, 2, 4 and 5 are carried through the outrigger and outrigger supports which are bolted to the frame. Load 3 is carried through the footboard and supports. Forces 1 and 3 occur at the same time and in opposite directions. By applying both of these forces through the supports, less total load is applied to the boat body. Forces 6 and 8 are applied to the frame through the carriage wheels which ride on the track which is immediately supported by the frame. By placing all of
these loads onto the structural frame, the forces which occur in the fore and aft direction are carried by the frame and supported by the shear strength of the foam. Loads placed in the up and down direction are dispersed by the grid and exploit the compressive strength of the foam. Thus, by dispersing these loads through the foam, the hull of the boat may be made of a light weight material and still be structurally sound.
Obviously numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention can be practiced otherwise than as specifically described herein.