Patent ID: 7438618

Claim:
A method for manufacturing a flotation device, comprising the steps of selecting a flexible fabric material and cutting the same to minimize fraying, selecting a polymeric sheet having a heat shrinkage coefficient substantially similar to said flexible fabric material and cutting said sheet to a preselected shape, forming an outer covering having a first side composed of said flexible fabric material and a second side formed of said polymeric sheet by substantially continuously joining said first and second sides to an edge portion also formed of flexible fabric material, so that said outer covering defines a partially enclosed void volume having at least one opening, everting said outer covering and closing all remaining openings except for a fill opening, filling a preselected quantity of a heat expandable and curable material sufficient to form foam having a density less than water into said void volume through said fill opening and then closing said fill opening after completion of filling, placing said covering having said heat expandable material sealed therewithin into a molding cavity having a preselected shape conforming to the shape of the finished device, heating said molding cavity to a preselected temperature and pressure for a preselected time to expand and cure said filled material and place said outer covering under tension, and cooling said molding cavity to formed a shaped, substantially rigid device of density less than water.