Patent Application
20130068154
This application is based on and claims the priority under 35 USC 119 of German Patent Application 10 2011 114 314.2, filed on Sep. 15, 2011, the entire disclosure of which is incorporated herein by reference.
The present invention relates to a body of a boat or ship including a hull made of metal sheets or plates of an aluminum-based material in the form of planks that provide the outer planking of the hull. The invention relates to watercraft in general, for which the terms boat and ship are used generally and interchangeably, for all sizes, types, applications and configurations of watercraft.
It is generally known to fabricate boat or ship bodies with a length from about 8 meters to about 20 meters using glass fiber reinforced plastic materials of various types by various fabrication techniques, including molding techniques, lay-up techniques, and spray-on application for example, in series mass production. On the other hand, hulls for ships or boats of this size category can also be conventionally fabricated using aluminum-based materials, but such metal boat hulls are typically fabricated one-off, i.e. one at a time, and largely by hand using many individual manual operations for assembling and finishing the metal components. Disadvantageously, the manual operations lead to inconsistencies or deviations, and the generally required welding operations can lead to warping and displacement of the components from the required contours and positions. Also, this manner of construction often requires jigs, clamps or fixtures that are temporarily welded onto the hull components for holding the components in place during fabrication, and that are later removed. These factors all give rise to a relatively high degree of required rework, post-work and finishing work to achieve the required finished contours and smooth fair surfaces. Namely, achieving the required hydrodynamic contour and smooth fair surface of such a boat hull of an aluminum-based material often requires considerable expense and effort in the need for grinding off weld beads, temporary weld locations, deformed contours, and the like, and smoothing such areas through the application, shaping and finishing of putty or mastic. In such cases, the thickness of the applied synthetic putty or mastic may actually even exceed the sheet metal thickness of the aluminum-based material of the hull skin or planking. This disadvantageously increases the weight of the hull by the weight of the applied putty or mastic, and also requires significant additional work. Furthermore the applied non-aluminum putty or mastic materials sharply limit the otherwise advantageous recyclability of the aluminum-based material of the hull. Thus, it is desired to provide a hull construction of aluminum-based material that avoids the need for non-metal putty or mastic and especially also avoids warping or deformation of the metal components during the fabrication.
The published French Patent Application having Publication Number FR 2 408 508 discloses a ship or boat body of the general type mentioned above, which has a hull made of several planks of an aluminum alloy that are welded together. For a boat hull length of approximately 10 to 12 meters, the thickness of the aluminum alloy sheets to be used for manufacturing this hull is at least 12 mm and is particularly selected so that the hull is structurally strong and form-stable without any transverse frame or rib elements, and can be used as such. However, there is a substantial weight disadvantage that results due to the significant thickness that is required of the aluminum alloy planks in such a manner of construction. Furthermore, the fabrication process is complicated because special forms or jigs as well as special welding devices are necessary for holding and clamping or tacking the planks in the required position while the welding is carried out.
Additionally, the published European Patent Application having Publication Number EP 0 049 871 discloses a boat hull that is assembled from plank-like aluminum profiles, which are pre-bent or pre-curved corresponding to the desired hull shape, and then the planks are joined with one another. Particularly, the individual planks have shank-like or flange-like projections that extend in the boat's longitudinal direction along the edges of the planks and that are screwed together with one another in order to connect adjacent planks.
Furthermore, U.S. Pat. No. 4,917,037 discloses a boat or ship body with a hull of metal, particularly aluminum, and an inner or upper structure of fiberglass. The fiberglass inner structure is set into and joined to the aluminum hull structure along an exterior perimeter edge of the hull forming a gunwale. The hull has a typical conventional kinked rib or bent rib cross-section, with a chine-like intermediate portion between the sidewall portion and the bottom portion of the hull. In addition to the outer skin, the hull further includes regularly spaced transverse frames or ribs as well as longitudinally extending stiffening beams or stringers. Particular construction details of the aluminum hull and its assembly are not disclosed.
The internet webpage http: //www.kastenmarine.com/frames_first .htm includes a discussion of various different methods for fabricating boat hulls of aluminum. Particularly, that webpage discloses a fabrication method called the “plate-first” method, which uses a 3D-CAD model, by which the metal plates that form individual plank elements are pre-cut corresponding to their respective desired perimeter configuration or developed plan form, and then so arranged that they are anchored one after another on specialized jigs or holding devices in the respective proper positions, where they are clamped or tacked and finally welded together with one another. According to the method described in this internet webpage, this process can be carried out without the use of a transverse rib framework. Instead, in such a known manner of assembling a boat hull, the transverse rib framework is only later inserted into and welded onto the hull planking or skin that has first been fabricated by itself as discussed above. A significant advantage of such a construction technique is that it can largely avoid the above mentioned undesirable deformations of the aluminum outer skin of the hull, which can otherwise arise when aluminum plank elements are welded to the respective allocated transverse ribs.
Furthermore, the above mentioned internet webpage http://www.kastenmarine.com/frames_first.htm, with regard to so-called single-chine hull shapes, mentions the advantage that the sheet metal plates used as plank elements for constructing such boat hulls do not need to be rolled or otherwise deformed before the assembly or construction of the hull. This article also mentions that it is possible to weld the rib or frame elements onto the plank elements before the assembly thereof.
All of the above discussed known fabrication methods require various auxiliary structures and devices, on the inside and/or on the outside of the hull, in order to carefully and sufficiently hold or tack the planking plates in place for then carrying out the welding. It would be desirable to reduce or eliminate the need for such auxiliary structures, holding devices, jigs, clamps, and other fabrication accessories, so as to simplify the fabrication process and thereby reduce the costs.
In view of the above, it is an object of the present invention to further develop a body construction for a ship or boat of the above mentioned general type, in such a manner that it can be fabricated in a simple and reliable manner using pre-fabricated elements as a building block system. A further object of the invention is to improve the fabrication process so as to minimize or avoid the need for jigs, clamps or other holding fixtures during the fabrication process, while still minimizing or avoiding the undesirable warping or other deformation of the metal hull plating during the welding and other fabrication steps. The invention further aims to avoid or overcome the disadvantages of the prior art, and to achieve additional advantages, as apparent from the present specification. The attainment of these objects is, however, not a required limitation of the claimed invention.
The above objects have been achieved according to the invention, wherein a watercraft body (e.g. a body for a ship or boat) comprises a hull made with aluminum-based material components and a superstructure (e.g. a topside structure or upper structure or any structure above the hull) that is fabricated as a separate unit and is then secured onto the hull by means of adjoining flange plates that are respectively provided both along an upper perimeter edge of the hull and a lower perimeter edge of the superstructure. In a preferred embodiment of the invention, the perimeter junction between the two flange plates extends parallel to the waterline or water plane, and is preferably located at an optimal height above the waterline to simultaneously serve as a structural support and carrier for a lateral fender profile member around the perimeter of the watercraft body. In this manner, the invention makes it possible to produce different watercraft bodies for various different applications, without requiring many special alterations, in that the same standardized hull of aluminum-based material can be combined with any desired one of different superstructures respectively having different forms, layouts, materials, etc. The different superstructures respectively all have the same identical flange plates as a basis, to ensure that any one of the different superstructures can be mounted on the same standardized hull.
According to further aspects of the invention, special structural arrangements and construction techniques of the hull itself are provided, so that the invention is also directed to such aspects of the hull itself, without regard to an optional final fitment with a superstructure.
For example, in an advantageous further embodiment of the invention, the fabrication and resulting structure of the hull is preferably as follows. Upper plank elements that will form side plates of the hull are first provided with rib or frame elements mounted on an inner side thereof, and these upper plank elements are then fixed to the flange plate that gives the plan form to the hull and forms the upper boundary of the hull. Lower plank elements that will form the bottom plates of the hull are provided with frame elements mounted on the inner surface thereof and are then joined to the upper plank elements, preferably by continuous welding to form a continuous longitudinal weld joint along the longitudinal seams between the adjacent upper and lower plank elements. Then the rib or frame elements on the inner surface of the hull plating are connected respectively with one another in the transverse direction, relative to the hull longitudinal axis, by respective allocated gusset plates as well as floor cross beams. The frame elements, gusset plates and floor cross beams are connected with one another by removable fasteners such as screws, bolts, clips or pins. Preferably, the frame elements are spot-welded onto the inner surface of the plank elements, and are further preferably additionally bonded continuously surfacially onto the inner surface of the plank elements by an adhesive that is injected into a purposeful gap between the facing surfaces of the frame elements and the plank elements.
Before they are mounted on the plank elements, the frame elements are initially fabricated each respectively with an individually hat-shaped profile including a spine or base web, two legs or shanks or side webs protruding at an angle from the two opposite edges of the spine or base web, and two contact flanges or mounting flanges respectively protruding at an angle from the distal or free edges of the two legs or shanks. The two contact or mounting flanges preferably include welding tabs that preferably have a slotted opening therein, at which the mounting flanges are spot-welded onto the inner surface of the plank elements. In the initial configuration, the individual hat-shaped profiles do not necessarily have perpendicular angles. Instead, the hat-shaped profiles are individually configured appropriately so that the bending of the respective plank element into the curved hull configuration during the fabrication process will result in the final required configuration, spacing and orientation of the frame elements. Namely, the plank elements are initially flat planar sheets when the frame elements are spot-welded onto the inner surface thereof. In this initial mounted configuration, the longitudinal spacing between successive frame elements may be irregular, and the orientations of the legs or side shanks of the frame elements may also be irregular. But then when the respective plank element is bent or curved to the appropriate hull contour during the fabrication process, thereby the longitudinal spacing between successive frame elements along the longitudinal axis of the hull is made uniform, and the hat-shaped profiles of the frame elements are bent or deformed along with the plank element so that in the final configuration the legs or side shanks of the frame elements are all aligned perpendicular to the longitudinal axis of the hull. To facilitate the proper placement of the frame elements on the plank elements, the frame elements preferably have index holes that can be aligned with corresponding index marks on the plank element or with an indexing fixture for placement of the frame elements. Thereby it is ensured that the respective frame elements forming one transverse frame structure will all lie precisely on the same transverse cross-sectional plane once the plank elements have been bent or formed into the required hull shape and welded together along the longitudinal seams.
The gusset plates and floor beams, which are fastened together by screws or the like to form the transverse frames, thereby give the hull structure the necessary structural strength and rigidity, and also provide mounting points for the attachment or mounting of further elements onto or into the hull. All of the components (e.g. plank elements, frame elements, etc.) have been pre-fabricated (e.g. designed, cut to shape, etc.) according to the requirements of the original design, for example by numerically controlled design, manufacturing and machining methods, such that the prescribed hull shape as designed will necessarily result once the components are assembled and connected together. The screwed or bolted connection of the frame elements, gusset plates and transverse beams avoids the need for weld-tacking and then weld-joining these components, and also allows a range of fitting adjustment of the components, for example especially allowing the longitudinal weld seams between adjacent plank elements to be adjusted appropriately. For example, the plank elements are assembled and bent or curved into the required configuration, and the frame elements, gusset plates and transverse beams are screwed or bolted together while making the necessary fitting adjustments, and then the longitudinal plank seams can be welded from the outside and from the inside. Because the fabrication of the boat hull according to the invention does not need any additional holding fixtures, clamps or the like on the outside or on the inside of the hull, therefore, the exterior longitudinal weld seams can be welded continuously with a single continuous weld bead joint, for example preferably by a welding robot according to a pre-programmed welding path, without hindrance or interference or interruption thereof by any clamps, holding fixtures or the like. This also minimizes or avoids warping or other undesired deformation during the assembly and welding process. Then the gusset plates bridging across the longitudinal plank seams on the inner side can be temporarily removed to allow continuous access to the longitudinal seams, so that the longitudinal seams can also be welded continuously by a continuous weld bead joint along the inner surface of the plank elements as well. Then the gusset plates are again screwed or bolted into the final assembled position.
After the complete assembly of all components and after completion of all welding operations, preferably the fabrication of the hull according of the invention further includes an adhesive bonding by which the rib framework is joined in a force-transmitting manner onto the inner surface of the previously welded outer skin or plating. For this purpose, the frame elements were preferably held at a defined spacing distance away from the inner surface of the plank elements, to form a defined gap for receiving the injected adhesive. By this adhesive, the outer skin or plating is bonded surfacially with the rib framework while avoiding the introduction of additional stresses and visible warping or deformations on the surface of the hull. The adhesive bonding additionally provides a noise damping and a thermal isolation break between the hull plating and the inner rib framework. This adhesive bonding further helps to prevent the occurrence of gap or crevice corrosion, increases the cyclic loading bending strength of the complete hull structure, and ties together the entire hull structure into a self-supporting section.
In order that the invention may be clearly understood, it will now be described in connection with example embodiments thereof, with reference to the drawings, wherein:
As shown in the vertical sectional view of
The structural details and construction of the hull 1 will be explained further with reference to the following figures. As can be seen especially in the perspective view of
The sectional illustration of
Particularly, the perspective view of
It is further apparent in
As can be seen in
A method of fabricating the boat hull 1 according to the invention will now be described, and can be understood in connection with
Next, the chine plates 15 and 16 and then the bottom plates 13 and 14 are assembled successively longitudinally adjoining onto the bottom (now upwardly facing) edge of the side plates 11 and 12. The structure is held together in the appropriate position to form the appropriate outer contour of the hull, in that the gusset plates 32, 33 and 34 as well as the transverse beams 31 are installed and screw-connected in order to tie together the respective adjacent frame elements, for example as represented in
Thereby, a closed water-tight hull skin has been established, which is supported by the framework within. Next, welding and adhesive bonding will be carried out from the inside of the hull, as follows. Because the exterior longitudinal weld joints already adequately hold together the plank elements, it is now possible to again temporarily remove the gusset plates 32, 33 and 34 by simply removing the screw fasteners. This provides a continuous uninterrupted access to the longitudinal seams from the inner side, for example as represented in
In an alternative embodiment, it is possible to produce adequate weld joints along the longitudinal seams without removing the gusset plates as described above. However, when the gusset plates remain in place, the welding is interrupted and it is difficult or impossible to form a continuous weld bead joint from the inside along the longitudinal seam. Therefore, the above described procedure is preferred, so that a continuous weld bead joint (extending continuously across an area of intersection with the transverse frame) can be established both along the outside and along the inside of each longitudinal seam.
Once the final assembled structure has been established as described above, then the gusset plates, transverse beams and frame elements are preferably additionally welded to each other to form a strong, permanently-joined, fixed framework. Additional longitudinal stringers can be provided if necessary, but are preferably omitted as unnecessary.
As another preferred step to further improve the strength and the load capacity of the resulting boat hull, the frame elements 21 to 24 are finally additionally adhesively bonded to the plank elements 11 to 14. As explained above, the slotted weld tabs 28 on the mounting flanges 27 of the frame elements 21 to 24 each include standoff projections 39 so as to form a defined spacing gap 38 between the frame elements and the plank elements, which are connected together by spot welds 41 on the weld tabs 28. The adhesive injection holes 29 provided in the frame elements communicate into this spacing gap 38. Preferably, adhesive channels 42 are additionally milled into the inner surface of the plates or plank elements 11 to 14 in registration under the injection holes 29 of the frame elements. Thus, as shown in
After the aluminum alloy hull 1 has been completely fabricated with the designed hull contour, with smooth and fair outer surfaces with essentially no deformation, as described above, a separately fabricated topside structure or superstructure 5 can be mounted on and connected with the hull 1 via the adjoining flange plates 10 and 50 as represented in
Preferably, the construction of the watercraft body is carried out with the aid of a 3D-CAD system, which numerically represents and specifies all individual components in their respective final installed positions and also as initial sheet metal blanks in a flat planar form. Because each individual component is numerically represented by all of its dimensions and other characteristics and by its initial layout as well as its final installed position and configuration, therefore all of the individual components and any desired variants thereof establish a digital building block system with high precision. The individual components, i.e. the individual building blocks, can then be selected from among available variants, and manipulated or further designed as a modular system for building watercraft bodies. The cutting, shaping and welding can also be numerically computer controlled and carried out via suitable robots. The screw connections can also be fastened and unfastened by robots. Alternatively or additionally, manual work can be performed as needed by fabrication personnel.
Although the invention has been described with reference to specific example embodiments, it will be appreciated that it is intended to cover all modifications and equivalents within the scope of the appended claims. It should also be understood that the present disclosure includes all possible combinations of any individual features recited in any of the appended claims. The abstract of the disclosure does not define or limit the claimed invention, but rather merely abstracts certain features disclosed in the application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 114 314.2 | Sep 2011 | DE | national |
