| 摘要 |
The present invention relates to the fabrication of boat hulls and other three-dimensional objects of thermoplastic sheet material. The process comprises heating a sheet of the material along a predetermined pattern of lines to a temperature at which the material is softened, placing the sheet in a jig with the material of the sheet still soft along the heated lines and folding it along the softened lines, and retaining the sheet in its folded state in the jig until the material along the said lines is cool and stiffens. The preferred thermoplastic material is polypropylene, and by reversely folding the sheet along selected fold lines an integral hinge can be induced. In making a foldable boat, the pattern of fold lines is such that the sheet in its folded state has the shape of the hull of a boat. A blank when so prepared can be rolled into extremely compact form for transportation and to erect the hull is merely unrolled and with a little manual assistance put into the required shape and secured. Gunwales, one or more stiffening members and one or more seats can readily be affixed.
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