The present invention relates to a form for the production of containers, such as boat hulls, and parts connected to the same, such as. decks, superstructure, etc. The form is to be coated with pla.stic material, such as glass fibre reinforced plastic, to constitute the container.

Different ways of holding down the cost in the production of ^" boat hulls have been sought by both do-it-yourself builders and manu acturers on an industrial scale. Thanks to production and sale of boats in different stages of construction, the boat builder can buy more or less complete hulls and by his own means provide the interior and motor, etc., thus reducing the cost somewhat. Forms for the production of boat hulls are also hired out to boat builders, but these forms- are clumsy and often heavy and therefore must be braced in a suitable manner when used. It is true that the cost for the production of the hull itself is held down, but the clumsine.ss cf the forms make them difficult to move, for which reason the boat builder must travel to the form in question and not the contrary. Cwinc- to this, costs arise for, among other things, transport of materials, personnel and the completed hull, as well as food and lodging for personnel. In addition, there arise costs for hiring a mobile crane for the removal of the completed hull.

It is the purpose of the present invention to provide a simple and inexpensive form for the production of boat hulls, whereby the above-mentioned problems are solved. This is practically achieved by making the form of a thin shell. The material of the shell is to be preferably plastic, such as hard plastic or foamed plastic. The material thickness cf the shell depends on the quality of the plastic as well as on the shell's shape and size. Preferably, the shell's thickness is to be 0.1-5 -on when it is made of hard plastic and 5-50 mm when-it is made

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of foamed plastic. The shell is to be spray-coated with plastic material-—for example, glass fibre reinforced plastic— or it may be coated with glass fibre fabric and plastic with the help of a roller, for the formation of the hull. The shell can, in some cases, remain; that is to say, constitute part of ^" - the completed construction. If the plastic is applied to the inside of the shell, the need for sanding and puttying is reduced. Nevertheless, the plastic may be applied equally as well on the outside, or on both the outside and the inside. In the latter case, a so-called "sandwich construction," best effected on a shell of foamed plastic, is obtained. The plastic coating can preferably be made on the shell when it is placed upside down or mounted on a base. Since the form is a thin shell, handling is easier and less expensive. Further simpli- fication of handling is obtained when the shell is produced in parts which can be .assembled at the time of use. Assembly is accomplished with self—locking parts, glue, tape or flanges or loose T-joints which are to be glued or which are provided with quick-coupling, in which case the flanges or T-joints can be shaped as housing, or in some other suitable manner, A large number of shells or shell parts can be transported and/or stored one within another. For example, 10 shells can, accord¬ ing to the present invention, be contained in the same amount of space as a completed hull. The shell is in itself an inde- pendent entity without need of braces, but it can, if it is appropriate, be provided with reinforcements in connection with mounting prior to use. The thin shell should be designed as a non-reusable form which can be mass-produced.

According to the present invention, the shell has been con- ceived in order to solve the problem of heavy, clumsy forms for the production of boat hulls. Those advantages gained by the use of said shell can even be utilized in the production of containers other than boat hulls. Examples of this are swimming

pools and silos for solid and liquid products. Assembly and mounting of the shell as well as its coating correspond in this case to the mode of procedure in the production of boat hulls _•

The present invention will be described in greater detail in connection with the three enclosed drawings, where

FIG. 1 shows schematically a thin shell according to the present invention, where

FIG. 2 shows a thin shell in parts, where F FIIGG.. 3 3 shows the shell according to FIG. 2 stacked together, where

FIGS. 4A

— 4F show surfaces of joints of the shell parts, where

FIG. 5 shows shell parts provided with flanges, where F FIIGG.. 6 6 shows T- oint arranged alongside a joint, where

FIG. 7 shows flange or T-joint shaped as housing, where

FIGS. 8A and 8B show external coating with plastic material forming the boat ^' hull, where

FIGS. 9A and B show internal coating with plastic material forming the boat hull and where

FIGS. 10A and 10B show external and internal coating with plastic material forming the boat hull.

In the figures, 1 is a thin plastic shell according to the invention. In FIG. 2 is shown schematically a division of the shell 1 into parts 2-5, which can be stacked in each other such as is shown in FIG. ^~ . In FIGS. 4A-4F are shown examples of shapes of self-locking joints 6 in the shell parts 2-5. According to FIG. 5 the two adjacent shell parts ^~ and 4

are provided at the joining point with flanges 9 and 10. The- flanges are in principal arranged perpendicularly to the respec¬ tive shell parts and are put together in a suitable manner} for example, by gluing or quick coupling. Two or more shell parts can in such a manner be provided with flanges. Flanges 9 and 10 can be so designed that these, after the shell parts aro joined ^■ form a supporting unit 12 according to FIG. 7. FIG. 6 shows an alternative junction of the two adjacent shell parts 3 and 4, where a loose T- oint 11 is arranged in a suitable manner at the joint. Such a T-joint 11 can be arranged at one or more of the joints of the shell's parts. Even in this alternative, the T-joints can be so designed that they form a supporting unit 12 for the mounting of the shell, such as is shown in FIG. 7» The boat hull is formed by the application to the shell 1 of the plastic material 8, which is applied by- means of a spray nozzle 7 to the outside, inside or both out¬ side and inside of the shell 1 such as is shown in FIGS. 8-10 _•

The shell, which should be coated preferably with glass fibre reinforced plastic for the formation of the boat hull, consists, according to the given example, of a thin, rigid plastic or of foamed plastic divided into stackable parts 2-5. 3y this means is obtained an inexpensive and easily handled form which is lightweight and not very bulky, whereby necessary transports can be made easier and cheaper. The shell parts 2-5, which ^a ^e furnished with self-locking joints 6, are eaεilj ^r assembled at the working site. The assembled shell 1 is to be coated by means of a spray nozzle 7 externally, internally or both externally and internally with glass fibre reinforced plastic 8. The coating is to be continued until the desired strength and rigidity is obtained in the hull. After hardening, the shell 1 can be removed oar can remain in the constituted hull. When the shell 1 is coated both externally and internally with glass fibre reinforced plastic 8, this can be accomplished either

simultaneously on both sides or first on one side and then on the other. A so-called "sandwich construction" is obtained through coating on both sides.

The shell according to the present invention has with reference- to the drawings been described for the production of boat forms; but, of course, the present invention is even applicable in the production of other containers and the like. Examples of this are swimming pools or silos for solid and liquid products.