# US 5,349,917 A · Unitary aluminum watercraft and method of production of same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,349,917 A - Document ID: US5349917A - Status: Granted - Kind: A - Application number: 08/005,462 - Filed: 1993-01-19 - Granted: 1994-09-27 - Earliest claimed: 1991-11-06 - Assignees: Marine Research and Development, Inc. - Inventors: Billy D. May - Web page: https://patentgrep.com/patent/US5349917A ## CPC - B63B 3/00: Hulls characterised by their structure or component parts (non-metallic hulls B63B5/00; designing, building, maintaining or repairing methods B63B71/00 - B63B83/00) - B63B 34/21: characterised by constructional features - B63B 73/43: Welding, e.g. laser welding - B63B 73/70: characterised by using moulds; Moulds or plugs therefor - B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06) ## Abstract A unitary aluminum watercraft is constructed from a single sheet of deep-formable aluminum by forcing a mold into the sheet to imprint the mold into the sheet and then forcing the perimeter portions around the mold. Excess sheet material is removed and than placed into a replica mold. A deck is installed and bonded to the interior bottom surface of the body by a structural flotation foam, such as urethane, to form a unitized structural beam which eliminates the need for a keel and the accompanying structural ribs and below-waterline rivets usually required. ## Claims ### Claim 1 A method of producing a watercraft for passengers having a unitary body comprising the steps of: A. forming a unitary watercraft body from a single unitary sheet of deep-formable metal; B. providing a mold in a desired shape corresponding substantially to the body of the watercraft; C. forcing the mold into the sheet of metal to cause the mold to imprint the shape of the mold onto the sheet; D. fabricating a rigid floor adaptable for attachment to the watercraft body; and E. attaching the floor to the watercraft body. ### Claim 2 (depends on 1) The method of claim 1 further comprising the step of: F. placing the sheet from step C into a replica female mold prior to step E and wherein step E includes the steps of; G. rigidly holding a floor member above the bottom interior surface of the watercraft body at a predetermined fixed height; H. injecting an expanding foam through openings in the floor member into the space between the interior surface of the watercraft and the lower surface of the floor member that will adhere to the respective surfaces and form a single continuous solid when it cures. ### Claim 3 (depends on 2) The method of claim 2 wherein step H includes the step of: I. injecting urethane foam. ### Claim 4 (depends on 2) The method of claim 2 wherein step F includes the steps of: I. placing the formed body in a mold substantially conforming to the exterior surface of the body for rigidly supporting the body in position; and J. removing excess material from the body perimeter to conform it to substantially the desired dimensions of the watercraft. ### Claim 5 (depends on 2) The method of claim 2 further including the steps of: I. placing the formed body in a first mold substantially conforming to the exterior surface of the body for supporting the body in position therein; J. removing excess material from the body perimeter to substantially conform it to the desired dimensions of the watercraft; K. removing the body from the first mold; and L. placing the trimmed body in a second mold conforming to the replica exterior surface of the body of the watercraft for rigidly supporting the body in position therein. ### Claim 6 (depends on 1) The method of claim 1 wherein step A includes the steps of: F. forcing the perimeter portion of the sheet onto the mold; and G. removing the formed sheet from the mold. ### Claim 7 (depends on 1) The method of claim 1 wherein step C includes the steps of: F. cutting a pair of oppositely disposed notches in the ends of the sheet each of which is aligned with the centerline of the sheet; G. grasping each end of the sheet substantially along the entire length of the end portion adjacent each notch; H. forcibly pivoting each of the grasped ends in an arc about an axis along the centerline of the sheet to force the perimeter portion of the sheet onto the mold; I. releasing the grasped ends of the sheet; and J. removing the sheet from the mold. ### Claim 8 (depends on 7) The method of claim 7 wherein step H includes the step of: K. forcibly pulling outwardly on the grasped ends of the sheet in a direction in line with the sheet centerline to place the sheet under tension for further forcing of the sheet onto the mold. ### Claim 9 (depends on 1) The method of claim 1 further including the steps of: F. cutting a pair of oppositely disposed notches in the ends of the sheet each of which is aligned with the centerline of the sheet; G. grasping each end of the sheet substantially along the entire length of the end portion adjacent each notch; H. forcing the mold into the sheet of metal to cause the sheet to imprint the shape of the mold onto the sheet; I. forcibly pivoting each of the grasped ends in an arc about an axis along the centerline of the sheet to force the perimeter portion of the sheet onto the mold; J. releasing the grasped ends of the sheet; K. removing the sheet from the mold; L. providing a replica female mold; M. rigidly holding a floor member above the bottom interior surface of the watercraft body at a predetermined fixed height; N. injecting an expanding foam through openings in the floor member into the space between the interior surface of the watercraft body and the lower surface of the floor member that will adhere to the respective surfaces when it cures; O. releasing the floor member after the foam injected in step N has cured; P. removing the watercraft from the female mold; and Q. joining together respective notched end portions at each end of the body. ### Claim 10 A passenger watercraft comprising: a unitary unfolded sheet metal body including a lower portion having an interior surface and opposite side portions and opposite end portions, said body being forcibly molded of deep-formable metal without folding thereof, said lower portion of said body having a continuous bottom throughout without welds below a waterline of said watercraft to minimize drag and to maximize resistance to leaks, said body having welds upstanding from said bottom at said opposite end portions; a rigid floor, said floor including a substantially planar floor member having an upper surface and lower surface, said floor member being located adjacent said lower portion and extending between said end portions and said side portions and contacting thereabout said interior surface of said lower portion; and means for attaching said floor member to said lower portion of said body between said interior surface of said lower portion of said body and said lower surface of said floor member, said means including a unitized structural beam engaged throughout said lower surface of said floor member and extending throughout the extent of said body lower portion below said floor member. ### Claim 11 (depends on 10) The watercraft as defined in claim 10 wherein said unitized structural beam consists of material formable into a substantially rigid continuous solid, said interior surface of said body lower portion and said lower surface of said floor member defining a cavity, said cavity being substantially filled by said material, said material adhering to throughout each of said interior and lower surfaces to attached said floor member to said body lower portion to become a rigid solid and provide substantial support throughout said floor member and minimize deflection of said lower portion of said metal body. ### Claim 12 (depends on 11) The watercraft as defined in claim 11 wherein said material is chemically expanded foam. ### Claim 13 (depends on 11) The watercraft as defined in claim 11 wherein said material is structural flotation foam. ### Claim 14 (depends on 10) The watercraft as defined in claim 10 wherein said sheet metal is aluminum. ### Claim 15 (depends on 10) The watercraft as defined in claim 10 wherein said floor member includes a plurality of spaced ports for the injection of said means for attaching therethrough, a plurality of closure members respectively capping each of said ports after injection of said means for attaching has been terminated. ### Claim 16 (depends on 10) The watercraft as defined in claim 10 wherein said body is in the form of a canoe having symmetrical and opposed sides and having asymmetrical end portions. ### Claim 17 (depends on 16) The watercraft as defined in claim 16 wherein said unitized structural beam includes a structural flotation foam material formable into a single continuous solid which adheres to each of said floor member lower surface and said interior surface of said lower portion of said metal body. ### Claim 18 (depends on 10) The watercraft as defined in claim 10 wherein said beam is a structural flotation foam material formable into a single continuous solid which adheres to each of said floor member lower surface and said interior surface of said lower portion of said metal body and occupies the space therebetween to form a single continuous solid. ### Claim 19 (depends on 10) The watercraft as defined in claim 10 wherein said rigid floor is sheet metal. ### Claim 20 (depends on 19) The watercraft as defined in claim 19 wherein said means for attaching includes welding said rigid floor to said interior surface of said lower portion of said body.