Process for producing boat hulls of sandwich construction

Claim 1

A PROCESS FOR PRODUCING A BOAT HULL OF SANDWICH CONSTRUCTION WITH AN OUTER PLASTIC SKIN COVERING AND A LIGHTWEIGHT RIGID CORE OF BEADED EXPANDED THERMOPLASTIC MATERIAL, COMPRISING THE STEPS OF FORMING A LOWER MOLD SECTION WITH AN INNER CURVED SURFACE TO PROVIDE A MOLD FORM FOR THE EXTERIOR SURFACE F A BOAT HULL AND AN UPPER MOLD SECTION WITH AN OUTER CURVED SURFACE TO PROVIDE A MOLD FORM FOR THE INTERIOR SURFACE OF SAID BOAT HULL, EACH OF SAID SECTIONS HAVING MEANS THEREIN FOR RELEASING THE BOAT HULL FROM SAID SECTIONS AFTER MOLDING, AND INLET MEANS FOR CHARGING THE MOLD CAVITY FORMED WHEN THE MOLD SECTIONS ARE PLACED TOGETHER, APPLYING MOLD RELEASE MATERIAL TO SAID INNER AND SAID OUTER CURVED SURFACES RESPECTIVELY, FOLLOWED BY APPLICATION OF A GEL COAT, ALLOWING THE GEL COAT TO BECOME TACKY, APPLYING A REINFORCING MATERIAL OVER THE TACKY GEL COAT, PLACING THE MOLD SECTIONS TOGETHER TO FORM A MOLD CAVITY, CHARGING PREFOAMED EXPANDABLE THERMOPLASTIC BEADS INTO SAID MOLD CAVITY VIA SAID INLET MEANS, THEN INJECTING AN EXOTHERMOUS EPOXY RESIN MIXTURE VIA SAID INLET MEANS INTO THE BEAD CHARGED CAVITY, SAI EXOTHERMOUS RESIN MIXTURE CHEMICALLY INTERACTING WITH EVOLUTION OF HEAT WHICH CAUSES FURTHER EXPANSION AND FINAL SETTING OF THE PREFOAMED BEADS TO PRODUCE A BOAT HULL HAVING A SOLID LIGHTWEIGHT CORE WITH EPOXY IMPREGNATED REINFORCING MATERIAL EMBEDDED ON THE EXTERIOR SURFACES AS A PLASTIC SKIN COVERING, AND REMOVING THE BOAT HULL FROM THE MOLD CAVITY UTILIZING THE RELEASE MEANS IN SAID LOWER AND UPPERMOLD SECTIONS.