Boat hulls

A method of fabricating a foldable blank for a three dimensional object of sheet material comprising the steps of:

• providing a self-supporting flexible, planar, solid sheet made of a thermoplastic polyolefin material of predetermined shape;
• heating the sheet on one face thereof along a predetermined pattern of lines to a temperature at which said thermoplastic polyolefin material is softened along said lines;
• folding the sheet along the softened lines in the direction of the heated face with the thermoplastic polyolefin material of the sheet still soft along said lines;
• retaining the sheet in its folded state until the thermoplastic polyolefin material along said lines is cool and stiffens;
• and folding the sheet in the opposite direction to the heated face along selected ones of said lines to induce molecular reorientation in the region of such fold and provide integral hinges along such selected lines, thereby obtaining a blank for said object in which said selected lines are hinged and the unselected remainder of said lines have folds that when flattened tend to return to their folded condition, and whereby said folded sheet is capable of being flattened for expediting storage and movement when not in use.

A method of fabricating a blank for the hull of a boat, comprising the steps of:

• providing a self-supporting flexible, planar, solid sheet made of a thermoplastic material capable of forming re-openable folds and integral hinges;
• heating the sheet on one face thereof along a predetermined pattern of lines to a temperature at which said thermoplastic material is softened along said lines, said lines defining fold lines required to form said blank into said hull;
• folding the sheet along said lines in the direction of the heated face;
• retaining said sheet in its folded state until the thermoplastic material along said lines is cool and stiffens;
• and folding said sheet in the opposite direction to the heated face along selected ones of said lines to induce molecular reorientation in the region of such fold and provide integral hinges along said selected lines and thereby forming a blank which can be folded up and when unfolded facilitates erection of the hull by reason of a tendency of the folds of the unselected remainder of said lines to revert to their folded state, and whereby said folded sheet is capable of being flattened for expediting storage and movement when not is use.