Blackwood builds its boats using what it calls HPI, which stands for high-pressure injection. It creates an outer hull of fiberglass mat, biaxial fiberglass fabric and DuPont Kevlar over the entire bottom for extreme strength and puncture resistance. Between the outer hull and the equally strong inner liner, Blackwood injects waterproof closed-cell-composite foam. The company claims its exclusive technology creates a strong, durable, flex-free, unitized structure that cuts through waves silently and smoothly to deliver a comfortable and confident sense of security. Additionally, Blackwood feels so strongly about the superiority of its construction technology that it offers a lifetime hull warranty!