ARRANGEMENT FOR CHANGING THE SIZE AND SHAPE OF THE BOTTOM SURFACE OF A WIND SURF-BOARD

Abstract: A wind surf-board to the underside of which one or several plate-shaped and rigid exterior bases are replaceably attached. To a wind surf-board belong a number of exterior bases attachable to the underside of the wind surf-board, one or several of which can be selected and attached prior to sailing. This is achieved by the underside of wind surf-board (1) being provided with a recess (2) in which exterior bases (3, 3') can be inserted and secured to the wind surf-board (1) by means of screws (6) etc.

Description: Arrangement for changing the size and shape of the bottom surface of a wind surf-board The wind surf-boards commercially available at the present time are, inter alia, on the one hand special boards and on the other hand so-called all round boards. Special boards are constructed for special conditions and. requirements such as strong or weak wind, large or small waves, good cruising characteristics, rapid turns, high capacity for carrying heavy persons etc. A distinguishing difference between various special boards consists in the size and shape of the bottom surface. With an all round board an attempt has been made to achieve a compromise between several special boards. The aim has been to create a wind surf-board with optimal character¬ istics for a number of conditions and requirements. However, an all round board has a given bottom surface as regards size and shape, which cannot be modified. This fact restricts the possibilities of achieving a wind surf-board with optimal characteristics for various different conditions and requirements. By the present invention as put forward in the characterising sections of the patent claims it is made possible for a wind surf¬ board to be adapted better to different sailing conditions and required characteristics by replacing the bottom surface. Since the bottom surface is in part replaceable it is possible, quickly to attach to the wind surf-board a bottom surface suitable for the prevailing conditions before beginning to sail. One embodiment of the invention is described in detail with reference to the drawings showing in a schematic form this embodiment of the invention. Figure _ shows a wind surf-board seen from the side with an exterior base located on its outside. Figure 2 shows a wind surf-board seen from below with an exterior base with fastening devices and a slot for a centre-board. Figure 3 shows a wind surf-board-seen from below with a recess in the bottom and an exterior base which can be fitted into the recess. Figure 4 shows a wind surf-board seen from the side with two external bases fitted to the outside. Figure 5 shows a wind surf-board seen from below with two exterior bases fitted. Figure 6 shows a wind surf-board seen from the side with an exterior board and fastening devices for the latter. Figure shows a wind surf-board seen from below with an exterior base without a slot for a centre-board. Figure 8 shows a wind surf-board seen from the side with an exterior base inlaid in the wind surf-board along the front edge but not along the rear edge. 1 designates a wind surf-board in the underside of which there is a recess 2 into which a rigid plate 3 ca be inserted and secured to the wind surf-board by- means of screws 6. The surf-board has threaded holes 4 in its underside. The screws 6 pass through holes 5 in plate 3 and into the threaded holes 4- -A- number of plates 3 of different sizes and shapes are available for one wind surf-board. As a result the user can, prior to sailing, select and fit a plate 3 which in his opinion is most suitable for the prevailing conditions. The wind surf-board 1 may be provided with a oentre-board case 7 which is open towards the bottom and partly open towards the top. The plate 5 may be provided with a slot 8 located in silch a way as to be in line with the lower opening of centre-board case 7 when the plate is fitted to the wind surf-board. As a result a centre-board can be inserted through plate 3- Plate 3 may also be without such a slot 8, which is desirable at high speeds when a centre-board is unnecessary. Plate 5 can also be secured to wind surf-board by making use of the fin fastening arrangements 9 on the wind surf-board and of centre-board case 7 * Thereby plate 5 can be provided with projecting parts 10 fitting into' the fin fastening arrangements 9 a d. centre-board case "J. The projecting parts 10 are secured to the wind surf-board by means of screws etc. The invention covers also non-flat plates 3 a d plates of a certain thickness in which non-flat surfaces have been formed. The scope of the invention also covers attachment of more then one plate 5 and fitting of plates 3 to the wind surf-board in another manner than here proposed, e.g. by means of a band surrounding the wind surf-board or by means of through-bolts.

Claims: Patent claims 1. A wind surf-board on the underside of which one or several plate-shaped and rigid exterior bases are secured c h a r a c t e r¬ i s e d in that the exterior bases (3.3*) are considerably shorter than the wind surf-board (1) and in that each and every one of them is in at least one common cross-section of the board and base wider than the wind surf-board (1) and in that to a wind surf-board (1) belongs a number of exterior bases (3.3') of different size and shape among which one or more can be selected and attached to the underside of the wind surf-board (l) prior to sailing, the said selected exterior bases (3.3') being secured to the underside of wind surf¬ board (l) by means of fastening arrangements integrated with wind surf-board (l) as well as fin fastening arrangements (9), a centre¬ board case (7), threaded holes (4) etc. 2. A wind surf-board in accordance with claim 1, c h a r a c t e r i s e d in that the exterior bases (3.3') are fitted to the wind surf-board (1) in such a way that parts projecting beyond the sides of wind surf-board (1) are not touched or intersected by an imaginary plane at right angles to the longitudinal direction of wind surf-board (1) and passing through the rear end of wind surf- board (1). 3- A wind surf-board in accordance with claim 1, c h a r a c t e r i s e d in that the exterior bases (3.3') are inserted in a recess (2) in the underside of wind surf-board (l) so that their respective undersides are flush or nearly flush with the underside of wind surf-board (1). 4. A wind surf-board in accordance with claim 1 , c h a r a c t e r i s e d in that the exterior bases (3>3') have curved surfaces.

Inventors: SILFVERSPARRE BENGT, SILFVERSPARRE, BENGT
Applicants: SILFVERSPARRE BENGT, SILFVERSPARRE, BENGT
Application year: 1985
Main classification: B63B35
IPC codes: B63B35